| nrgy |
Just curious, what are the disadvantages to using a full range driver, rather than a tweeter/woofer combonation? For example, if I used a 3" speaker with a frequency range of 100-20,000 Hz for full range, would sound quality/output be that much different that a typical bookshelf, say 5" woofer/ 1" tweter? (other than the obvious lower freq. range). However, if used in tandem with a powered sub, than this perhaps would be a moot point?
Just asking because I am looking to build a full range speaker using the Tang Band W3-881S 3" driver.
Thanks,
Jeff |
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| li_gangyi |
yoz...I;m not answering your question, as you will see below, but rather I,m also interested in the same project. but with a slightly different driver...check this page out
http://home.new.rr.com/zaph/audio/audio-speaker11.html
I assume it has got to do with reduced power handling...but I suppose it wouldn;t really affect in my application (which is a good pair of speakers for my PC...). I;m having some trouble sourcing such drivers in Singapore too...so if you do know of a good one that does worldwide shipping...lemmi know... |
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| Geek |
| The phase cancellation problems of a multi-speaker system tend to color sound by creating a "comb filter" effect at the frequencies near the cross. However, the single driver plan is to let one driver handle the mid/high frequencies to eliminate this and a narrow-range LF driver (banpass boxed sub for example) for the bass. Since hearing is pretty much non-directional below 100Hz, the phase cancellations should be neglible and the comb effect at the crossover should be minimized. |
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| CeramicMan |
High frequencies would definitely be smoother and more natural with a dedicated tweeter. However, taking into account a price of around ~US$17, that "fullrange" speaker could indeed perform better than a midrange+tweeter+crossover combo costing the same amount.
At higher prices though, I doubt that fullrange speakers can keep up with speakers that are separated into narrower frequency ranges. Otherwise, people would have by now widely given up on using separate tweeters and midranges. |
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| Geek |
| Ahhhh, but what if the fullrange is a $90 USD jobbie? :bigeyes: |
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| 7V |
I'm a big fan of the full-range driver approach.
Apart from the phase problems at the crossover point, there are problems with dramatic changes in the dispersion characteristics of the different drivers. There are also significant differences in timbre between the cone bass units and dome or ribbon tweeters, often made of a different material.
To make matters worse, the crossover point is generally in the mid-band where our hearing is most sensitive. As Geek has pointed out, these issues are less significant in the bass where wavelengths are longer, hearing is less sensitive and room modes cause large fluctuations in amplitude anyway.
I believe that the main reasons that full-range drivers are not more widely used are:-
1. It's not so easy to manufacture full-range drivers of high quality.
2. The consumer is used to the boom and tizz of conventional speakers and consider that sound to be 'hi-fi'.
3. Most manufacturers are like sheep. Just look at the pictures in any hi-fi magazine.
Good luck with your Tangband speaker, Jeff. One thing though - is the power handling of a single TB adequate for your needs? If not you could use two drivers mounted vertically but as close together as is physically possible. |
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| CeramicMan |
| quote: | Originally posted by Geek
Ahhhh, but what if the fullrange is a $90 USD jobbie? :bigeyes: |
Likewise, people can buy $90 tweeters. Most tweeters work on the same principle as wide-range speakers - ie: they have soft domes, and all of the vibrations are actually partial oscillations which means there are usually lots of underdamped resonances in even the flattest parts of the FR curve. I'm a fan of hard cones and domes so that speaker vibrations are as pistonic as possible. Even if it means that multiple sound sources are needed and that they will interfere with each other. Comb filtering is non-resonant, and is IMO relatively benign in the context of speakers, otherwise nobody would like the sound of line-array loudspeakers. |
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| Nuuk |
The answer to the question depends much on the full-range driver used and particularly it's size.
If you are lucky will will be able to cover from 90 Hz to around 10K without any crossover and the associated problems described in the previous posts.
In short, I would say that I can't hear any disadvantages but I can see them, if you don't like large sized speakers. ;) |
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| 7V |
| quote: | Originally posted by CeramicMan
... Most tweeters work on the same principle as wide-range speakers - ie: they have soft domes...
... Comb filtering is non-resonant, and is IMO relatively benign in the context of speakers, otherwise nobody would like the sound of line-array loudspeakers. |
The full-range speakers that I have seen or used are cones not domes. Many of them, such as Bandors or Jordans, are anodized aluminium, not soft. I believe that the Tangbands are also cones.
I'm not sure what you mean when you say that comb filtering is relatively benign. It manifests as a large drop in output at certain frequencies and line-arrays are generally designed to keep it to a minimum. I suggested that, if two TBs were used, they should be mounted as close together as possible because this would minimize comb filtering.
Incidentally, Nuuk, you can do much better than 10kHz with a small full-range driver. I didn't understand your remark about large speakers. Why should they be large? |
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| CeramicMan |
| quote: | Originally posted by 7V
The full-range speakers that I have seen or used are cones not domes. |
What I meant was that they tend to be soft and flexible eg: paper Tang Bands, paper is soft and flexible - in the context of frequencies like 5kHz that is; and the Jordan philosophy is to use aluminium that's so thin that their cones are flexible too.
Though I agree in that if I were to go for a full-range speaker, I'd look for something with a hard cone. Eg: the AuraSound NS3-193-8A, from Madisound and it's priced similarly to the Tang Band one. |
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| 7V |
| quote: | Originally posted by CeramicMan
What I meant was that they tend to be soft and flexible eg: paper Tang Bands, paper is soft and flexible - in the context of frequencies like 5kHz that is; and the Jordan philosophy is to use aluminium that's so thin that their cones are flexible too. |
Good points, CeramicMan. Personally, I think that the Jordans are too thin and they suffer nasty break-ups as a result. The Bandors though are not as thin and, at the 5kHz frequency quoted, are rigid as anything. The cone contour also contributes to stiffness.
Incidentally, as the Bandor drivers are a little thicker than the Jordans, I choose the 4 ohm versions because they have the lowest moving mass. I'm probably over fussy. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by nrgy
Just curious, what are the disadvantages to using a full range driver, rather than a tweeter/woofer combonation? |
Everything is a comromise. Yes, using a fullrange driver instead of a same diameter woofer plus tweeter carries a penalty in some areas and gains in others.
| quote: | Originally posted by nrgy
For example, if I used a 3" speaker with a frequency range of 100-20,000 Hz for full range, would sound quality/output be that much different that a typical bookshelf, say 5" woofer/ 1" tweter? (other than the obvious lower freq. range). |
The Fullrange Driver would likely have a much lower maximum SPL (smaller diameter) at low fequencies, less extended and detailed upper treble and I think the point in SPL for complex music (eg large scale classical) where the sound would start to "congest" would be lower than for your postulated Tweeter/Woofer combo.
On the plus side, there is usually a coherence, togetherness and reality to a fullrange system that is highly appealing.
One way around the limitations is of course the kind of system often called "FAST" in Germany, probably best rendered as "Fullrange Assisted". You could use the 3" Fullrange and combine this with a 5" or even 6.5" Woofer (or larger) using a very low crossover point, like 250Hz. If you wanted a higher sensitivity and powerhandling you could use a short line source made out of several of the 3" Drivers (2 - 4 pcs) and combine that with a "serious" woofer.
Both drivers will at least within the crossover region around 250Hz and over a few octaves up and down have a pretty flat frequency and inpedance response, making ths system easily ameanable to a 1st order series crossover with textbook values.
The resulting speaker should have all the positive attributes of a fullrange system but offer the bandwidth and power handling of a classic multiway speaker.
Many, many Years ago I build a similar speaker back in East Germany. This was originally based conceptually on a replica of a commercial speaker then widely sold in East Germany which used a closed basket 6"X4" oval full range driver as "tweeter" and an 8" Woofer in a 20 liter sealed box with a crossover at around 600Hz. These originals did not sound too bad at all, often outperforming expensive imported 2/3/4 Way speakers.
At the time I got the open basked full range version of the same oval driver first from some speakers given to em and started building boxes and picked up cheaply some nice 10" Woofers from russia while on holiday there (the 10" Radiotechnica).
I ended up with a crossover around 300Hz IIRC and a 40 Liter sealed box with a chamber for the "Fullrange" driver and this sounded great for a first DIY Speaker and in fact better than anything what was available commercially then in East Germany.
I went the usual path of HiFi after that alternating between multi-way systems (the most extreme a pair of Coral 5-Way Speakers which however at their core where 3-Way speakers with a wideband midrange and horn supertweeters), Studio Coaxials and Fullrangers.
These days I'm back on Fullrangers for the time being, right now custom made versions of the Supravox Fieldcoil Driver targeted at open baffle operation, supplemented by Subwoofers (REL Quake X 2) and Supertweeters (Visaton TL-16H).
Sayonara |
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| Nuuk |
| quote: | | Incidentally, Nuuk, you can do much better than 10kHz with a small full-range driver. I didn't understand your remark about large speakers. Why should they be large? |
I wouldn't expect to go as low as 70 Hz with a 3 inch full-range driver Steve! ;) By using the large diameter FR's (10 inch plus) they can run right through the frequency range that contains 95% of the music without having a crossover.
Of course I am basing this on using an OB arrangement although I apperciate things change with a box (for the worse ;) ) |
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| 7V |
| quote: | Originally posted by Nuuk
I wouldn't expect to go as low as 70 Hz with a 3 inch full-range driver Steve! ;) By using the large diameter FR's (10 inch plus) they can run right through the frequency range that contains 95% of the music without having a crossover. |
When I was at Paul Messenger's getting the speakers reviewed, we noticed that his pen recorder was recording significant output at 20Hz with the Little Awesome bass speakers turned off. This was just with 2" Bandor drivers, although I use four of them each side.
I see what you mean with the 10" full-rangers. If you visit EAR's factory, you will hear Tim de Paravicini's large box speakers with large full-range drivers. If you're lucky, he'll turn the volume up and take you out of the factory and across the car park to demonstrate how realistic they sound, even at a distance! They had the old drivers with Alnico magnets.
I'd say that large full-rangers are a good way to go. |
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| Timn8ter |
| John K's plans for the TB W3-871S does indeed produce a very smooth sounding system. I've tested it with and without the notch filter and the difference is noticeable. He recommends the sealed designs for increased power handling over vented and in fact doesn't offer a vented design like the Creative Sound Solutions Elf designs. The CSS designs offer a little more bottom end. While John's design does offer better power handling it is still somewhat limited in the single driver configuration. However, if you mate the sealed design with a 5" woofer such as the W5-704S and put in an even order XO at ~500Hz power handling goes way up. I've just started on this particular approach so it'll be a while before I come to any exact conclusions. For a PC speaker it's hard to find anything better than the single W3-871S design. When considering price, performance, size and versatility for use in a low power/near-field application I've not found anything that can touch it. |
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| li_gangyi |
| hehx...I sure am glad to hear that~!...wooo imagine a fews hrs infront of the PC watching anime and listening to music...mwhahahaha I rock~!!! I;m planning to supplement it with a smallish subwoofer..probably at the 200 or 150Hz point...any comments?? |
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| Timn8ter |
Combining the John K. W3-871S 0.1ft^3 design with notch filter and a small "subwoofer" creates a PC speaker system without rival in it's price range. John offers a description of a small inexpensive "sub" but there are many to choose from for this application.
Disclaimer: Using the term "subwoofer" in this way is not really accurate but it's become the common venacular. :D |
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| sek |
Sorry to go a little off topic here...
| quote: | KYW:
Many, many Years ago I build a similar speaker back in East Germany. |
So You are from East Germany?
I still got some lovely speakers working at home.
RFT standard chassis, though, but nice. They were constructed at home in the mid-80s ;)
Sebastian. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by sek
Sorry to go a little off topic here...
So You are from East Germany? |
Yes, in those old days of the last millenium when the Great Wall of Berlin was the pride and joy of every citizen (NOT).
| quote: | Originally posted by sek
I still got some lovely speakers working at home.
RFT standard chassis, though, but nice. They were constructed at home in the mid-80s ;) |
A lot of the RFT stuff was actually rather good. We used to joke "RFT = Reicht Fuenf Tage" (lasts 5 days) but there is a lot of classic RFT out there that is more than a few cuts above the average. With some TLC any of the old Heli KG Sensit Series stuff can sound great (especially their valve Kit). The K-20 "Kugellautsprecher" may have had it's problesm but in many ways it too was rather outstanding.
Go RFT Hunting would be my suggestion, especially the better Pro and Semi Pro stuff and a few select generic "HiFi" Models (BR-25/50 I hope I don;t have to mention specifically).
Sayonara |
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| Nelson Pass |
| quote: | Originally posted by 7V
When I was at Paul Messenger's getting the speakers reviewed, we noticed that his pen recorder was recording significant output at 20Hz with the Little Awesome bass speakers turned off. This was just with 2" Bandor drivers, although I use four of them each side. |
When I see that, I turn off the air conditioning. :cool: |
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| 7V |
| quote: | Originally posted by Nelson Pass
When I see that, I turn off the air conditioning. :cool: |
This is England, Nelson. Most of us have only just got fridges. :D |
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| PeteMcK |
My only full range effort is a pair of old 5" Sharp drivers,
I put them in a K slotted pipe for extended bass,
They're pretty good, but the soft paper cones tend to break up with higher vols/ complex music.
I bought a bottle of Damar varnish last week, I want to see if stiffening up the cone improves them
Pete McK |
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| dvdwmth |
| quote: | Originally posted by li_gangyi
hehx...I sure am glad to hear that~!...wooo imagine a fews hrs infront of the PC watching anime and listening to music...mwhahahaha I rock~!!! I;m planning to supplement it with a smallish subwoofer..probably at the 200 or 150Hz point...any comments?? |
I'm using Johns smallest tangband speaker without the notch filter (ill try the filters later but I was impatient to here these drivers) and a 12" that runs a little bit higher than the usual sub rolloff point. I'm quite floored by the sound quality. Im using these for my main music system, not on the computer, and I highly recommend giving them a try. In combination with the lm3876 gainclone amp they're amazing. I promise you you will be happy if you build these. Try the amp too if you dont already have really good amplification. Its worth every bit of effort. |
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| li_gangyi |
| I do have an amp...based on a LM3875, and not 6 as I was lazy to include the mute resistor. They sound pretty good for their price (no botique parts though) with metal films and mylar input caps...I guess I'm gonna use them again for my PC speakers that I'm building... |
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| navin |
ways to use a fullrange:
1. fullrange (single, 1.5way or line source)
2. small fullrange (2-3") with woofer support below 300Hz (approx)
3. large fullrage (6-10") with tweeter support above 6k (approx).
4. as a wide range with support below 300Hz and 6k (approx).
option 2 and 3 are essentially 2 ways and 4 is a 3 way.
I dont think anyone can qualify that one option is better than the others or that any of these is better than a "regular" 2 or 3 way.
to do this one needs a budget. Now lets say we got a budget of $120 per side ($250 for a stereo pair, $600 for 5 channels).
At this budget u can either use
a JX92 or 4 x Fostex 107E ...OR
a Fostex 85k with a woofer such as the SEAS H333 or Vifa M21,... OR
a Fostex 206/207 with a FT17H or other tweeter...OR
a Fostex 127 with a $70 10" woofer (SEAS H372 or Vifa M26) and a FT27D or other tweeter...
OR
replace the Fostex fullrange above with a dedicated midrange like the Vifa M10 or Seas H143
note i refer to fosex/seas and vifa but these can be replaced by other drivers.
so within a budget u have 5 choices of topology atleast more if you iconsider different manufacturers.
confused? so am i! :) |
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| Nuuk |
OK guys, who is 'talking the talk' and who is 'walking the walk'?
A rare chance to get one of the best full-range drivers.
See here .
(I have no connection with the seller). ;) |
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| li_gangyi |
| oh ****...I just found out that shipping for these drivers I mean the TB ones...are at 44USD...compared to a unit price of each driver, which is 8USD...it simply...what can I say...sucky...wonder if there's a solution... |
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| 7V |
| quote: | Originally posted by Nuuk
OK guys, who is 'talking the talk' and who is 'walking the walk'?
A rare chance to get one of the best full-range drivers. |
The Goodmans Axiom drivers were (I'm almost certain) designed by Ted Jordan (of Jordan). Doreen Bance (Bandor) was in charge of production.
Navin, nice summary btw. |
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| navin |
7V,
actually i was being rather simplistic. amplifier wattage, max SPLs required, WAF, music listened to, application are other factors.
I find that once one applies all factors to a speaker selection you are normally left with only 1 or at best 2 choices.
of the choices i listed earlier for example if my amp was a 10W SE tube I'd have little choice but to sue the Fostex 206 with the FT17H to achieve decent SPLs or if WAF was a big concern I'd might have to use the JX92 in small 12-15 liter boxes, etc...hence once you starts applying other factors the choices you really have are quite narrow. |
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| 7V |
| quote: | Originally posted by navin
actually i was being rather simplistic. amplifier wattage, max SPLs required, WAF, music listened to, application are other factors.
I find that once one applies all factors to a speaker selection you are normally left with only 1 or at best 2 choices. |
True, but still it gives a 'beginner' something to think about other than the conventional 2-way design. |
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| navin |
after going thru about 10 conventional 2,3,4 way designs over the past 25 years or so (I built my first 3 way speaker in 1976) and not yet finding the holy grail I am ready to try fullrange/widerange.
my speakers included drivers from philips, focal, dynaudio, jbl, morel, audax, scanspeak and vifa and maybe others. |
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| Timn8ter |
I'm wondering if the answer for me will be found with a 3 way that uses an extremely wide range mid say from 500 to 10k then augment with a woofer and super-tweeter. Either that or a two way 500 (or lower) to 20k and augment the LF. Or, it could be that's it's just a matter of money and the answer is the Exact full range from Japan that sells for ~$5000.
:cannotbe: |
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| 7V |
I remain convinced that the crucial thing is to
a) keep the crossover point(s) WELL away from the mid-band.
b) WORSHIP the mid-band with cabinet design or open baffle.
Then you can use whatever type of bass loading and room interaction that you prefer. |
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| CeramicMan |
| quote: | Originally posted by 7V
I remain convinced that the crucial thing is to
a) keep the crossover point(s) WELL away from the mid-band.
b) WORSHIP the mid-band with cabinet design or open baffle.... |
Amen to that.
I think the real problem is a severe shortage of true midrange units that are available to the loudspeaker market. Most midrange units seem to compete on bass performance, while sacrificing the performance of their primary function. There are plenty of midbass speakers between 100mm to 210mm that manufacturers falsely claim are good up to 3, 4, or even 5kHz. In reality many such speakers suffer from poorly controlled partial oscillations from frequencies as low as 700Hz - well before the sound starts becoming directional. They often have excessively long voice-coils and large rubber surrounds for good bass, but this can make midrange resonances worse due to the increased mass.
For top "wide-range" midrange speakers I'd look at some of the offerings from manufacturers such as Seas, Accuton, Visaton, Eton and a few others. |
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| Ken L |
| quote: | Originally posted by Kuei Yang Wang
Everything is a comromise. Yes, using a fullrange driver instead of a same diameter woofer plus tweeter carries a penalty in some areas and gains in others.
|
Which is why I personally prefer Gordon Rankins suggested nomenclature of " Wide Band Augmented" drivers, because there is no true "full range driver" that covers the "full range " of the normal audio spectrum
| quote: | Originally posted by 7V
I remain convinced that the crucial thing is to ....
a) keep the crossover point(s) WELL away from the mid-band.
b) WORSHIP the mid-band with cabinet design or open baffle.
. |
You left off "horns" here _grin_
as you make your compromises and particular choice of preference - one rule of thumb is give a driver/horn/cabinet combo a primary decade to handle and go from there - In that normally, to achieve "flat" response you are limited by driver/horn combination to a decade or so
Soooo, if you can stretch your decade a bit and/or place it carefully in regards to crossover points - you then may be on the road to maximizing a wide band setup -
I'll be trying a number of crossover points and slopes later and will post my results.
Will try fo ensure that this coincides with a listening session with some others listening also. _grin_
REgards
Ken L
Regards
Ken L |
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| nonamekid |
| Bi-amp Jordan JS92xs, active crossover in the 100s, stereo subs. Simple, clean, fat. |
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| Robh3606 |
Heres my take on this
There is no one driver that can handle the whole spectrum. Plain and simple. You will be using a crossover be it the roll off of a sealed box a cap,caps and coils or natural roll off the driver. You just can't avoid it. Keeping the crossovers out of the midrange is a good idea providing you can get a driver that can give you reasonable response from about 100 hz and up and not turn into a laser beam at 10K. That is no easy task so the whole exercise is a balance of trade offs just like a multidriver design. Question is which set of trade offs are you more likely to live with?? For me I like 4 ways with steep crossovers 24db L/R. Phase just doesn't seem to bug me all that much. I would rather have the a more constant directivity, power handling, lower power compression and lower harmonic distortion that a multidriver system offers.
Rob:) |
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| nrgy |
Wow, thank you for all the responses! Throughly anserwed my questions and then some. I went ahead and bought a couple TB w3-881s drivers. They are fairly inexpensive, and I figured this should be a great beginner project seeing I don't have to use a crossover, and a cabinet/box should be fairly easy make. Plus, I can easily play with different box sizes and such.
Another question I have is how to properly read the power handling figure. For example, the w3-881s says 15w rms/30w max. If I hook them to a receiver that puts out say 100w per channel, this exceed the power handling rating by quite a bit. I know I'm misinterpreting this rating, just not sure how. |
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| navin |
| quote: | Originally posted by Timn8ter
I'm wondering if the answer for me will be found with a 3 way that uses an extremely wide range mid say from 500 to 10k then augment with a woofer and super-tweeter. Either that or a two way 500 (or lower) to 20k and augment the LF. |
if you are looking at this might i suggest a fostex FF85K with a good paper woofer. I am also looking at this but most woofers i find need a bigger box (<25l) than I can get away with.
| quote: | Originally posted by CeramicMan
For top "wide-range" midrange speakers I'd look at some of the offerings from manufacturers such as Seas, Accuton, Visaton, Eton and a few others. |
in the midrange (250hz-5000Hz) what do you think of Audax's aerogel drivers?
| quote: | Originally posted by nonamekid
Bi-amp Jordan JS92xs, active crossover in the 100s, stereo subs. Simple, clean, fat. |
one solution. great waf too. only i wonder if it has the slam to handle rock. |
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| CeramicMan |
| quote: | Originally posted by navin
...in the midrange (250hz-5000Hz) what do you think of Audax's aerogel drivers?... |
Can't say I've heard them, at least not that I know. To me they seem similar to Vifa speakers. The non-resonant plastic chassis seems like a good idea, though it looks like Audax is doing the same as all manufacturers of soft cones: trying to control partial resonances as nicely as possible. |
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| Vix |
Full Range Drivers- Yes!
However....I have a problem with what is supposed to be a fairly good fulrange driver- Fostex FE 206 e. Since I couldn't wait for horn enclosures, I temporary mounted Fostex in a sealed enclosure. The result-horrible:bigeyes: It sounded thin and harsh, with peaking midrange and beamy highs. I felt as If I was listening to a cheap PA speaker:bawling:
Then I added a BSC circuit: 3 mH inductor-10ohm 10 w resistor and a zobel. Much better- the midrange peak was gone. Unfortunately, it still sounded thin and harsh. Then I tried another thing: I connected a 33 ohm 15 W resistor in series with the driver. WOW! The result was much better-at a cost of a greatly reduced efficiency. So I could listen to a low volume only...
I also borrowed a pair of B&W DM 601 from a friend. Actually, they sounded much better than Fostex....
I don't want to get rid of Fostex, nor I like them as they are now. Is there any solution? Will horn enclosure cure these flaws? Any comment? Nelson? Kuei?
p.s. The amp is ZEN V3 |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by Vix
However....I have a problem with what is supposed to be a fairly good fulrange driver- Fostex FE 206 e. Since I couldn't wait for horn enclosures, I temporary mounted Fostex in a sealed enclosure. The result-horrible:bigeyes: It sounded thin and harsh, with peaking midrange and beamy highs. |
Predictably. One part is the severely tipped up frequency response (whch can be equalised), the other are fundamental problems with drivers like the Fostex.
Lets start with the first set of problems. Fostex's published response looks like this:
As you can see, the response in the range from 250Hz to around 1.5KHz is pretty flat at around 95db/2.83V/1m. Above that the response is shelved up on axis by around 5 - 6db with the worst on axis peaks being nearly 10db above the mean response.
The off axis response is flatter, I cannot tell at which angles this is taken but it may very well be 30/60 Degrees, which suggests that most of all the drivers should be listened to far off axis or you need to shelve the range above 1KHz down by around 6db across the range with an attenuation of around 10db at 10KHz.
One way to equalise this response is to do this acoustically by using a suitable front horn, which will boost the output below around 1KHz, such as the Oris 150 or Azurra Horn. In fact, ONLY EVER in such an Horn (and NOT in a rear only horn) can the range between 250Hz-10KHz ever be balanced using this driver and avoiding equalisation.
At low frequencies another problem makes itself known. If we place the driver ino a 30 Liter sealed box with 30cm baffle width and place it optimally near a corner for LF boost (that means using the golden ratio for hight above floor, distance to rear wall and distance to sidewall) we get an LF response looking likely a lot like this:
You need to "splice" the LF response from directly above to the HF response above 1KHz from the Fostex Datasheet to get a goo idea what is going on.
So, at 10KHz our SPL will be around 105db and at 100Hz our SPL will be around 85db. In other words, from 100Hz onwards the frequency response is boosted with 10db per decade so that at 10KHz there is 20db more SPL than at 100Hz!!!!!
There is simply no way to equalise that completely and thus an LF horn MUST be employed if any LF reproduction is desired.
The use of current drive BTW may very well bring the LF output in line. For fun here is what happens if the source has an internal impedance of around 33 Ohm:
(note, I scaled Re to "fudge" the effect of a High Z source with 2.83V applied, not easy to do in the spreadsheet without programing Re' - that is any source impedance in to be included but compensated)
We now have a balanced LF response and if we deliberatly roll off the treble a little, either with a parallel network or with an active EQ we should have a balanced sound.
| quote: | Originally posted by Vix
Will horn enclosure cure these flaws? |
As you can tell from the above, the answer is:
Not completely! You can use a rear horn to get the low frequencies balanced but you will still have problems with the upper midrange and treble.
I guess you have to buy a "FirstWatt" amp from Nelson or build something similar or combine a rear horn and RLC EQ.
Sayonara |
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| Nelson Pass |
The FE206E anf FE166E are my favorites of the Fostex product,
but they do require some work.
I recommend that you look at the article at www.firstwatt.com
in reference to the kind of network that will do the job. Note
that it is not essential to run a current source amp, rather you
want to have an amp with a finite impedance whose value is
optimized around the type of enclosure, it's location in the
room, and your taste. You also want to try a parallel RC network
whose value depends on the source impedance and your
taste.
:cool: |
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| eric180db |
| Here is the biggest problem with single driver. Dopler distortion. If you have a 3" speaker that has to modulate 3mm just to produce audible bass (due to its limited surface area) the midrange and treble will now be prduced from a moving source. even worse, the smaller the driver has to be to accuratly produce treble the more excursion there is to produce, say ,50hz. therefore the only way around this problem is to use many drivers to increase surface area. but if not done carefully you get the same comb filtering. but now its at all frequencies above the wavelength of the array. That is why its generally better to take your chances whith phase cancelation at one frequency like in a 2 or 3 way system. |
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| navin |
wow. this means a drivers like the jx92 and 167e require some serious cabinet design.
maybe one can avoid doppler as well as phase by using bending wave transduces like Audio Physiks DDD driver or Manger or maybe even using 2 widerange drivers (one choice I am considering is the Fostex FF85K with a yet unchosen 6-10" woofer) with a 1st oder XO.
What if one were to take a 166/167/206/207 type driver load it with a ML-TL like Bob Brines, GM, Abpea and co do and place the tower against the rear wall to further boost the bass? |
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| ScottG |
doppler distortion? I think not.
phase shifting with resulting time-domain alterations, yup! but this is an area where the average fullrange driver is better than other traditional solutions (i.e. vs. your typical 2-way).
you can get around the time domain problem by utilizing the high excursion driver axially pointing upward or downward (and have a polar response for the driver that is very close to being omni).
oh and since the 206E has come up.. check out this design:
http://www.audio.co.jp/speaker/sou.htm |
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| serenechaos |
On the topic of a good cabinet for the FE206E... :smash:
Are you familiar with the Decware HDT? (High Definition Tower)
http://www.decware.com/HDT/hdt.htm
TL with 2 passive radiators each, ~ 35 Hz to 18 kHz, 96 dB efficient, recommend 1.8 ~ 30 watt amp. The cabinet design has deep, tight, accurate bass from “below 40 Hz”, “flat out to 18KHz.” Plans, pre-cut panels and empty enclosures are available. |
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| Vix |
Thank you!
I appreciate the detailed and comprehensive reply
:)
Even though my ZEN V3 is recently built, I already started thinking about building a current source amp:cool: (but I'll have to wait a year or two till Nelson publishes the schematics for F1:D )
In the meantime, I will have to play with ZEN and correction circuits...
BTW, the upward-firing Fostex looks interesting, but I don't understand any Japanese:(
ScottG, can you possibly find that in English?
regards
Vix |
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| 7V |
| quote: | Originally posted by eric180db
Here is the biggest problem with single driver. Dopler distortion. |
I assume that this is something you've read somewhere because I've never found anyone (on forums or in 'real life') who has actually experienced Doppler distortion.
If you have though, please report back and let us know precisely how it sounds. Doppler distortion is an interesting-sounding, mythical creature. I doubt if it actually exists. |
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| navin |
maybe the effects are so subtle that we cant hear it...
maybe we are so used to this we dont recognise it...
maybe our ear-brain actually hears it but corrects for it...
i do believe that we at present are not able to measure enough parameters in the audio domain to allow the measurements to determine if a product sounds good or not. this means we do not understand the educated ear-brain enough. maybe doppler (if it exists) is one of those missing parameters. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by eric180db
Here is the biggest problem with single driver. Dopler distortion. |
I wish that was the biggest problem with single drivers. Sadly, it is not the biggest problem.
In fact, it's not even a big problem. It's not even a small problem. It's problem that actually is a VERY, VERY small one. It's so small, for all intents and purposes, it can be safely ignored.
So, please ignore the little man behind the curtain.
BTW, reproducing the midrange through a driver that has it's cone moving significantly still causes problems, but they are down to magnet design and other such electrical and electromechanical non-linearities, not down to "doppler distrtion".
Sayonara |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by Geek
Try this :) |
Well, an enclosure like this will not solve many of the problems (there will remain a 10db tilt upwards at high frequencies) but it will now introduce at least one major one.
Namely a severe LF power handling problem, making the use of a Highpass at around 80...100Hz mandatory. The highpass needs to be probably at least 2nd order, so now we have the 6th order Highpass function around 80Hz. That is most definitly NOT GOOD.
If you wher eto use a small sealed enclosure and a 2nd order Highpass with some boost at the corner frequency you would have a much better result while keeping the rolloff order at a sensible point.
I would still think that using a larger sealed enclosure (say 40 Liter floor standing column) together with Nelsons suggested principle of a high output impedance amplifier makes a lot more sense, as it will actually turn the system into a true fullrange system with pretty good overall response.
While obviously reviled among the Pass Labs Boards contributors, the kind of Chipamp often known as "Gainclone" can be used to make a transconductance amplifier (current output) on a shoestring and there it is also possible to incorporate the EQ networks into the feedback loop, making the whole excercise quite inexensive to try.
Sayonara |
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| stefanobilliani |
| quote: | Originally posted by Kuei Yang Wang
Konnichiwa,
While obviously reviled among the Pass Labs Boards contributors, the kind of Chipamp often known as "Gainclone" can be used to make a transconductance amplifier (current output) on a shoestring and there it is also possible to incorporate the EQ networks into the feedback loop, making the whole excercise quite inexensive to try.
Sayonara |
At Elliot Sound Products page there is an interesting example of
variable impedance amplifier |
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| Geek |
| quote: | Originally posted by Kuei Yang Wang
While obviously reviled among the Pass Labs Boards contributors, the kind of Chipamp often known as "Gainclone" can be used to make a transconductance amplifier (current output) on a shoestring and there it is also possible to incorporate the EQ networks into the feedback loop, making the whole excercise quite inexensive to try. |
Have you tried actually using the speaker as part of the FB loop? Similar to an op-amp mechanical reverb driver stage. Tried this once with an LM-12 Wonderfully smooth highs!
<<edit>>
Bah, simulposters :rolleyes:
Yeah, his diagram :D |
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| Vix |
Thanks, but I would rather prefer a sealed than ported...
In fact, as neither of them are suitable for FE 206E, and a horn can be quite difficult to build, I am wondering if the transmission line will work? Some folks have built Martin J. King's "Virtual Fostex FE-206E and FE-207E ML TL Design" and they seem to be satisfied with the result...
I did not mention it in the first post: I am also using two DIY sealed subwoofers, each using 12" driver, whith the active, equalized crossover at about 65 Hz. In fact, it is controlled by Rod Eliott's "Subwoofer Processor-P.48". So it seems that in this arrangement Fostex can work in a big sealed enclosure...
Regards
Vix |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by Vix
Thanks, but I would rather prefer a sealed than ported...
In fact, as neither of them are suitable for FE 206E, and a horn can be quite difficult to build, I am wondering if the transmission line will work? |
Not much better. The problem is the Driver.
That particular design, if driven from a Voltage source will be balanced ONLY EVER on a Front horn or with severe EQ.
The TL can offer a little more bass than a sealed box by virtu of adding resonant reinforcement of the sound, but it can only do so much.
| quote: | Originally posted by Vix
I did not mention it in the first post: I am also using two DIY sealed subwoofers, each using 12" driver, whith the active, equalized crossover at about 65 Hz. In fact, it is controlled by Rod Eliott's "Subwoofer Processor-P.48". So it seems that in this arrangement Fostex can work in a big sealed enclosure... |
No, the Fostex cannot work in a big sealed enclosure as there will remain a 20db difference between the level at 100Hz and at 10KHz. Once you have taken measures (whatever they may be) to equalise the response between 100Hz & 10KHz you can think of extending the LF with a subwoofer. But the main task remains to address a 20db level increase between 100Hz and 10KHz!
Sayonara |
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| ScottG |
"but I don't understand any Japanese"
I don't either.. it was more of a visual representation to what I was suggesting.
But just from the look of it - it appears to be a TQWT design because of the "pyramid expansion". In fact if your NOT shooting for a low freq. response then a TQWT should be able to lift the lower-end of the baffle loss region similarly to a back-horn because the bandwidth of the TQWT's resonance is broader than something like a pipe or a passive radiator. Additionally there should be a freq. balance shift just by firing the driver upward that would decrease the driver's spl as freq. increases - assuming your listening at close to 180 deg.s off axis then I would suspect that "shift" occurs near the baffle-loss region. Of course this is all speculation, BUT if you have a 206E then you can always load the thing in a cheap sealed box, aim it upward and measure it to see how it affects the freq. balance. (..of course without the reflector the high freq.s will be significantly reduced above 1kHz.) |
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| JinMTVT |
what about using an ELS in a hybrid system has many commerical units ?
the crossover point can be made really low ( sub 200hz )
and the esl makes for a "full range" driver from 200hz to supersonic freq. ??
i also guess that an esl doesn't suffer from much of the cone drivers problems ? aside from dipole wich can be work around with a semi closed box ( wings? )
hope i'm not too off subject here :p |
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| eric180db |
| its not just easy to test for doppler distortion, its also easy to hear. Build a good single driver system and if you had 2 sin sources you can play 1 khz and 40 hz simultaneously and at a reasonable listening level you will definitly hear a warble sound in the 1khz now do the same with a normal 2 or 3 way system you will notice that its far less or none at all depending on the crossover points. Most people dont have 2 signal generators so you pick out music that has alot of low bass and clean vocals. The louder it is played the more of this effect you will hear and it is inversly proportional to the surface area of the cone. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by eric180db
its not just easy to test for doppler distortion, its also easy to hear. Build a good single driver system and if you had 2 sin sources you can play 1 khz and 40 hz simultaneously and at a reasonable listening level you will definitly hear a warble sound in the 1khz now do the same with a normal 2 or 3 way system you will notice that its far less or none at all depending on the crossover points. Most people dont have 2 signal generators so you pick out music that has alot of low bass and clean vocals. The louder it is played the more of this effect you will hear and it is inversly proportional to the surface area of the cone. |
But how do you know that you are hearing/measuring doppler distortion, not just simple intermodulation aused by the magent field non-linearity (or more preciesly the mudulation of BL and thus sensitivity with cone travel)?
So, no doppler distortion, just a not so well designed magnet field.
Sayonara |
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| 454Casull |
| quote: | Originally posted by Kuei Yang Wang
Konnichiwa,
But how do you know that you are hearing/measuring doppler distortion, not just simple intermodulation aused by the magent field non-linearity (or more preciesly the mudulation of BL and thus sensitivity with cone travel)?
So, no doppler distortion, just a not so well designed magnet field.
Sayonara |
Hypothesis directly to conclusion?
:confused; |
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| rcavictim |
Youre both right! It's a desert topping and a floor polish! :D
This is a Saturday Night Live quote that shows my age. |
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| eric180db |
| True there will be these components too but not to the extent of the doppler distortion and if you wanted to find out which is which you just look at the measured 1khz fundimental on an "o"-scope or even better on a 1/3 octave spectrum analyzer. The scope will show the wavelength changing with the low frequency component (an effect that will not happen with IMD or HD) the spectrum analyzer will actually show a flickering around the 1khz mark causing the next octave up and down to modulate. Before arguing try the experement for yourself and see if you can explain the results. |
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| navin |
I am considering using a fullrange for HT. the fullrange will be supported by the LF out (subwoofer signal).
does the fullrange have to operate in the bass (below 100Hz) or is it ok to use a fullrange that is bandwidth limited. The reasons I ask this is that I am hoping to get by with a small box (10-12 liters) and that means a small driver (max 5"). and a small driver will not produce much below 100hz at any thing close to HT levels.
reasons for using fullrange
1. no need for XO design or XO losses
2. the box can be oriented verticaly or horizontally without worrying about polar response changes like one would in a MT.
right now I am leaning towards the JX92. Only I wonder if it's LF and HF response would be adequate for HT. How would one compate the sound of a small fullrange (so far I have only heard the Manger with 8" Vifa woofer, a large Fostex and the Lowther and that too only in audio mode not HT) to say that of a small 5" 2 way monitor?
another option is to use a wide range with a small woofer. like a Fostex FF85K with a Vifa PL 11WH, Seas CA11RCY, Audax HM100G0 and XO at about 400-600Hz. However most of these small woofers have response that is very good upto 3000Hz+. In that case does it make sense to use such a woofer with a small format tweeter like the Seas CT25AF or Vifa D26NC or Audax TM010?
lastly if one were to use a small wide range like the FF85K in a 1.5 way with a small 4" woofer (no XO on the woofer) there will be considerable overlap between say 500Hz and 5k. How would this affect the sound? The reaons for this is that a passive 1st order LP XO at 500hz would require a large cap that would be detrimental or expensive or both. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by eric180db
True there will be these components too but not to the extent of the doppler distortion |
You are right, they will be not to the extent of the doppler distortion, they will many times as high.
| quote: | Originally posted by eric180db
and if you wanted to find out which is which you just look at the measured 1khz fundimental on an "o"-scope or even better on a 1/3 octave spectrum analyzer. The scope will show the wavelength changing with the low frequency component |
Will it? Sure?
Why don't you just stop repeating the same old fairytales?
http://sound.westhost.com/doppler.htm
Sayonara |
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| john k... |
| quote: | Originally posted by eric180db
...or even better on a 1/3 octave spectrum analyzer. The scope will show the wavelength changing with the low frequency component (an effect that will not happen with IMD or HD) the spectrum analyzer will actually show a flickering around the 1khz mark causing the next octave up and down to modulate. Before arguing try the experement for yourself and see if you can explain the results. |
(JPK) Doppler distortion IS IM distortion. See my analysis at http://www.geocities.com/kreskovs/Doppler1.html and check some measured results at http://www.geocities.com/kreskovs/Doppler2.html
It is true that you can seperate motor induced IM and cone motion induced doppler (IM) but the analysis clears shows that Doppler distortion (cone motion generated) is identical to, and there fore is IM distortion. You won't see flickering on a spectrum analizer, just the fundamentals and the IM side bands. On a scope you will see the higher frequency "riding the wave" of the low frequnecy like a cork bobbing over ripples in a pond. The peaks in the high frequency will ride up and down and back and fourth as the low frequency modulates it. |
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| catapult |
John is, of course quite correct that Doppler distortion is real. We are all just so used to hearing it that we don't recognize it for what it is. SL also did an analysis along with measurements to confirm its accuracy.
http://www.linkwitzlab.com/frontiers.htm#J
http://www.linkwitzlab.com/images/graphics/doppler1.gif
Short formula for the magnitude (I originally derived this from John's stuff and SL's formulas agree.)
Doppler distortion % = 0.91 * (max 1-way excursion in mm) * (highest freq in kilohertz)
An example, since we're talking full range drivers, say the max excursion is 1 mm and the highest F is 10kHz. The amplitude of the sidebands will be about 9% of the 10kHz tone or a bit over 20dB down. That's a pretty high distortion number and, in addition, you aren't going to get much bass out of a small driver only moving 1 mm. |
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| RHosch |
Disadvantages of full-range drivers?
(1) Large IM and other non-linear distortions (there are many mechanicms for this in full-range drivers)
(2) Low SPL capability as frequency drops
(3) Poorly controlled dispersion
(4) Poor frequency response
There are of course advantages as well. |
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| Jennice |
OK... we now know that there are problems associated with full-range drivers. We also know that they have advantages, primarily because there is no (or limited) need for additional components.
Then what is the problem with the following:
Use a full-range driver for the frequency range, say, 300 Hz to 6kHz
Use a 6" woofer below this, and a tweeter for the highs, wach with simple 1. order filters.
Funny phases from complex filters would be avoided, costs are reasonable, and there are no XO frequencies where it really hurts (where the ear is most sensitive).
I haven't build such one (haven't built ANY speakers yet, actually).
However, I would like to give it a try some day, and have found tons of information in this forum. Thus, I would like to have comments on this approach, hoping it's not too far off topic.
Jennice |
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| 7V |
| quote: | Originally posted by Jennice
Then what is the problem with the following:
Use a full-range driver for the frequency range, say, 300 Hz to 6kHz
Use a 6" woofer below this, and a tweeter for the highs, wach with simple 1. order filters. |
Jennice, I don't think that there's anything at all wrong with proceeding as you've suggested and it could make an excellent construction project for you.
I would tend to go a little higher than 6kHz, say 9kHz, particularly with 1st order crossovers, and perhaps take the lower crossover down a little for the same reason.
I would recommend either an open baffle approach or an 'egg' type enclosure for your main driver (but that's me). ;)
I believe that you could end up with something way better than most of the commercial products out there. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by Jennice
OK... we now know that there are problems associated with full-range drivers. |
Problems have solutions....
| quote: | Originally posted by Jennice
Then what is the problem with the following:
Use a full-range driver for the frequency range, say, 300 Hz to 6kHz |
The problem is that your first X-over is smack bang in the Formant Range of many instruments and your second in the middle of the upper harmonics.
Consider dropping the first X-Over as close to 100Hz (or lower) as power handling of the Fullrange Driver allows. Secondly, leave the Fullrange driver running "open top", with no lowpass. Select a Fullrange that rolls of nicely and supplement the top using a suitable high overtone reproducer (Supertweeter in Neo-Audio English).
| quote: | Originally posted by Jennice
I haven't build such one (haven't built ANY speakers yet, actually).
However, I would like to give it a try some day, and have found tons of information in this forum. Thus, I would like to have comments on this approach, hoping it's not too far off topic. |
I did that sort of thing back in the mid 1980's. I had a long going active speaker project that started like this:
Dual 8" Sealed Woofer Section
Singe 5" Fullrange (no Whizzer)
Single 1" Supronyl Dome tweeter
Starting point where Low Order X-Overs (active) at 250Hz/5KHz. Later versions left the Fullrange running without lowpass and with a suitable highpass and current feed on the Fullrange. Tweeter changed to Piezo (motorola) at around 10 - 12KHz with a steep Highpass slope. Woofers eventually went the Servo Way.
You know what? Afer a few years of incermental work on that system it was very good and in all "HiFi" terms whooped the butt of my "normal" speaker. But when it came to making music sound such that I wanted MORE I preferred my other speaker.
That had 2psc of Schulze KSP215 (8" Fullrange Drivers, with Whizzer) in a rather classically aligned vented box, a simple choke on one of the drivers cutting it out at higher frequencies (maybe 500Hz or so).
I also regulary find myself coming back to systems where the main "wideband" or "fullrange" driver is run completely open (no HP, no LP). Even the EPOS ES14 and ES12 I liked, despite having a rather low rolloff point on the main driver, but that rolloff is purely mechanical.
Not sure what the lesson is, except that of "Suck & See".
Sayonara |
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| Jennice |
| quote: | Originally posted by Kuei Yang Wang
[The problem is that your first X-over is smack bang in the Formant Range of many instruments and your second in the middle of the upper harmonics.
|
1) What's the formant range (first XO)?
2) The middle of ther upper harmonics... you mean that there's lot's of mucic information there, so I should select a different frequency?
| quote: |
...Singe 5" Fullrange (no Whizzer)...
|
What's a whizzer?
| quote: |
...But when it came to making music sound such that I wanted MORE I preferred my other speaker. |
You mean that it was technically good, but almost boringly neutral?
The wide-band would probably be the Vifa TG9WD10-04, one of the few fullrange drivers I know where I can buy. What do you think of it? (data sheet link:
http://www.d-s-t.com/vifa/data/tg9wd-10-04c.htm )
It sounds temptingly simple to rrun a full-range without HP filter, and letting it mechanically roll offf at the low end, but I fear it will seriously be limiting the power handling of the final speaker. After all, it will have to play loud at times, and my concern is that the membrane will be shot across the room :D
As an alternative, I think I know where to purchase Visaton drivers. Does anyone know about these?
Jennice |
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| Jennice |
I've found a Visaton FRS8 full range driver, which costs about 1/3 of the vifa driver. However, I don't know if it's worth going for. any comments?
Jennice |
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| navin |
| quote: | Originally posted by Kuei Yang Wang
Problems have solutions....Consider dropping the first X-Over as close to 100Hz (or lower) as power handling of the Fullrange Driver allows. Secondly, leave the Fullrange driver running "open top", with no lowpass. Select a Fullrange that rolls of nicely and supplement the top using a suitable high overtone reproducer (Supertweeter in Neo-Audio English) |
I was looking to do this for a HT-cum-audio system but ran into one more suspicion.
say we use a fullrange like the Jordan JX92 which can be XOed below 100hz and still handle 20W (13dbW) to produce about 100db/1m/100Hz.
put a TL/MLTL/Dipole woofer below 100hz.
so far so good...
if one is to add a tweeter about 8/10k (I was recomended the Hiquphon or Fountek) for the "final octave" and run the fulrange with a LP wont there be some polar interference?
another option is to use a widerange that does not HF help (like the Fostex FF85K) but usually such fullranges cant go much below 300hz which means that one has XO to a small woofer (4-6") and then to a larger woofer below 100hz. I dont like 2 passive XO points so close. I suspect they would interfere unless the system was biamped or triamped. of course one can sacrifice HT requirements of LF and use a pair of 8" instead. |
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| Kuei Yang Wang |
Honnichiwa,
| quote: | Originally posted by Jennice
1) What's the formant range (first XO)? |
The range where the FORMANTS (that is the first few overtones of the fundamental notes) reside. They are called formant as they "form" the tone. Maybe you wish to study some theory of musical insytrument sound prior to building speakers?
| quote: | Originally posted by Jennice
2) The middle of ther upper harmonics... you mean that there's lot's of mucic information there, so I should select a different frequency? |
Not quite. What I am saying is that either X-Over you suggested is in the middle of ranges critical to the percieved tone. Change the diaphragm material, mess with the phase and the like and life gets interesting.
As said, all this is basic musical/acoustial theory.
| quote: | Originally posted by Jennice
What's a whizzer? |
A small second inner cone used on some fullrange speaker sto extend the high requrncy range and to give wider diepsersion oat high frequecies. Please goole for more.
| quote: | Originally posted by Jennice
You mean that it was technically good, but almost boringly neutral? |
Yes, but also lacking coherence.
| quote: | Originally posted by Jennice
It sounds temptingly simple to rrun a full-range without HP filter, and letting it mechanically roll offf at the low end, but I fear it will seriously be limiting the power handling of the final speaker. |
That would mean you have chosen a unacceptable fullrange driver. :-)
Sayonara |
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| m@ |
I've been experimenting with a Fostex FF85K crossed over to two 15's circa 300 hz w/ 4th order slopes.
I'm running the whole thing OB, hence the two 15s per side. I have the 15s EQd flat to close to 20 and they're still barely moving. God bless big pro drivers.
I've spent a lot of time trying different crossover points and slopes. I've ended up with 4th order since I'm running the Fostex only an octave above Fs. It's moving within a small fraction of its available xmax (they really move in and out running them full range, fun to watch).
I'm not set on 300, but in terms of being nonobtrusive it's a good choice. If you run the speaker with the top turned off, you can tell there's not a whole lot detail below 300. I was really worried about cutting the male voice roughly in half, but our lack of sensitivity below 300 predominates. Yes, the fundamentals are shifting between the Fostex and the big drivers, but it's not distracting. It's only noticeable, to me, because I'm specifically looking for it.
I've tested any type of music you can imagine - and there is some IM/breakup with complex music. Interestingly, higher crossover points (300 - 1000) don't seem to alleviate it. But it's at quite high levels (and in mono, which means one driver doing double duty).
Higher crossover points are intrusive tonally in comparison. It's immediately obvious and the sound is worse for it. Of course, all of my favorite manufactured speakers are crossed over in points I wouldn't - but in this speaker there's no comparison. Keep it out of that critical band.
I've also swapped in a Vifa Midbass/Tweeter combo (but not their highest quality stuff) and that lack of coherence is immediately noticeable as well.
The bass? Man, that's a whole other story. Anyone who complains about dipole power needs to use bigger drivers. Are dipoles modal? Yes, not nearly as much as omnis - but we alreay knew that. Do they shake and rattle things if you want them to? Yes, no problem. I know the net pressure change in the room is 0, but everything shakes anyway.
That Fostex is a charmer. It's not a very small full range. It's a very natural sounding tweeter that goes really, really low. Don't underestimate it.
:) :) |
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| navin |
| quote: | Originally posted by m@
That Fostex is a charmer. It's not a very small full range. It's a very natural sounding tweeter that goes really, really low. Don't underestimate it.
:) :) [/B] |
How does it compare to others (Tangband W3xxx, Jordan JX6, Veravox 3, etc...) fullranges? I would suspect that the Veravox might be closest to it. |
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| m@ |
No idea actually. When I first had the idea I stumbled across the Fostex. I haven't tried anything else.
For me, the criteria is that its top end is comparable to a dome tweeter (full extension, good off axis) and it can reach down comfortably sub 500 hz. I would guess all of those drivers qualify, but I haven't looked into them.
It seems that there has to be some form of decoupling between the center 'tweeter' section and the larger cone. The Fostex seems to do a good job of this with some type of lossy material connecting the 'dome' dust cap and the cone. They've also done a lot of work on the surround, apparently to give it a large xmax while keeping everything as linear as possible. The frame is stamped, but everything else seems to have been given a lot of thought. It's a lot of driver for 30$.
The only question lingering is whether or not there is a lack of dynamics in the lower midrange (compared to the incredible dynamics in the bass). That's the only area where the design is pushing its limits, so I'm wondering if it could be improved. I have yet to do adequate testing to set the EQ and crossover flat, so I'll hold judgement until then.
I have tried filling in the midbass with a different, larger driver, but there is a lack of coherence as the upper XO point then has to be 500 - 600 or higher. |
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| navin |
The FF85K needs 24db/octave to be used at 300Hz? It cant do with a shallower slope?
I agree the FF85 is a lot of driver for $30. The Jordan costs 4 times as much. I have not seen the Veravox 3 (also $30) to compare; wonder if it can go lower than the FF85K.
With the intention of using one driver from the lower midrange 200Hz+ I am also investigating the larger Jordan (JX92), Veravox (5s), and Supravox (135). The Jordan might be the best bet as it's is very flexible for the kind of boxes it can be used with.
Another option might be the Fostex 103/108. Although all of these options will come at the cost of an extended treble. |
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| badman |
I'll be trying the Fostex FF225K in a "Rethm the second" cabinet: the idea for it was that it was fairly similar in behavior to the preferred lowther DX4, but with somewhat lower Qts, Xmax (but in an underhung coil, Xmax means less than with overhung), and much smoother response, giving up the top octave. A Raven R1 rolled in first order at 10k ought to add just the sort of sparkle the unit needs.
Funny thing, the initial plan is to drive this speaker with the Motorola DCP501 tripath receiver: too many speakers in the house hahahahaha :) $90 receiver driving some pretty fancy cabinets/drivers :)
You know your speaker building has gone to excess when you're about to ask your boss if you can warehouse a couple pallets worth at work :) |
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| m@ |
For me it was the balance between a low xo point and power handling / IM. A 4th order slope let me maximize that.
I've also tried it with 1st, 2nd and 8th order slopes. To me the 4th order sounds the best. I originally thought 2nd order would be better since it could give a better 'blend' between the Fostex and the 15s - but the 4th order seems to make the most seamless transition.
Yeah, I've looked a lot into 4 inch or larger drivers. But most of them seem to have a compromised high end. One of the reasons I find this current design so appealing is that it puts the XO into wavelengths that are very forgiving, in a sense. Based on my sims, and some feedback from a career designer, putting the XO at 300 eliminates lobing errors at the XO point.
The thought of having to roll in a supertweeter - and the impossibility of getting them aligned - puts me immediately off. A three inch driver in my mind is the best compromise for getting around the critical hearing (and design) band.
I'd like to try out some jordans. I'm not willing to spend the money on them until I've extracted every ounce of quality out of these lower priced drivers. I'm also not thrilled about the idea of an aluminum cone, although I've heard good things about the jordans.
But to answer your question, you can technically run the FF85K full range. It has a lot of xmax for a little driver (can't remember the number), so can handle just about any bass waveform (non-EQd of course) you can throw at it. It gives audible distortion on tracks that most other, larger speakers distort on.
I was originally going to use it full range with a sub rolled in, which is very possible, but I think this design is better overall.
If you're thinking about taking a full range driver down to circa 200 - I can't recommend it enough. After just a couple of weeks of testing, I think there is a lot of potential in that type of design. If you look at most graphs of excursion vs frequency, the 'take off' point is right around there - which means your bass drivers is going to still handle the lion's share of the heavy excursions. Crossed over at 300, I can't see the fostex moving. |
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| planet10 |
| quote: | Originally posted by Jennice
Use a full-range driver for the frequency range, say, 300 Hz to 6kHz
Use a 6" woofer below this, and a tweeter for the highs, wach with simple 1. order filters. |
Something similar is falling into place here... FE108eS, Jordan JX150, AC 2si... i figure active XOs in the 200/8k range....
dave |
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| navin |
| quote: | Originally posted by m@
Yeah, I've looked a lot into 4 inch or larger drivers....Based on my sims, and some feedback from a career designer, putting the XO at 300 eliminates lobing errors at the XO point.
The thought of having to roll in a supertweeter - and the impossibility of getting them aligned - puts me immediately off.
I'd like to try out some jordans. I'm not willing to spend the money on them until I've extracted every ounce of quality out of these lower priced drivers.
But to answer your question, you can technically run the FF85K full range...I was originally going to use it full range with a sub rolled in, which is very possible, but I think this design is better overall.
If you're thinking about taking a full range driver down to circa 200... the 'take off' point is right around there - which means your bass drivers is going to still handle the lion's share of the heavy excursions. Crossed over at 300, I can't see the fostex moving. |
How come 300hz? I find it a little high. My requirement comes from the fact that I intend to use the same speakers for 2 ch. audio as well as 4.1 or 5.1 ch. HT/AV.
The speaker system would be centered around a fullrange that can be used for wall mounted center and rear channels without ANY bass augmentation.
The front channels would have a 12" woofer and if nesscary a helper tweeter like has been done with so many JX92 designs. It would a biamped 4 box system with 2 woofer boxes and 2 HF boxes. The HF boxes have a size limit of about 9 liters and will be wall mounted flanking a LCD TV.
My 2 choices for the fullrange was either a single 4" (the JX92) or a multiple smaller speakers (to improve power handling) like the 85K array shown in te PDF below http://www.fostexinternational.com/..._fw85k_tboy.pdf
The 0.1 channel would be 2 12" woofers similar to the woofer used in the front channels.
All Amps would be solid state given size constraints.
| quote: | Originally posted by planet10
Something similar is falling into place here... FE108eS, Jordan JX150, AC 2si... i figure active XOs in the 200/8k range....
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where are the details of such a system? Is the JX150 still in production? |
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| planet10 |
A strange attractor is bringing all these together here on the mountain....
FE108eS is my favorite midrange (and an ideal candidate for help on the bottom), and a pair that needed some TLC came my way... they now have phase plugs (fixed the problem with the dustcaps) and will be guinea pigs for some C37 that also found its way here. The ribbons were a bribe for some work i did, and the JX150s a payment towards some work i haven't done yet.
dave |
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| planet10 |
| quote: |
where are the details of such a system? Is the JX150 still in production? |
No JX150 -- they are made of unobtainium these days. Due to being cash poor, i had to sell the pair i had bought so long ago... but 3 more -- all with some small problem to fix (making then not worth selling) -- just came into my possession... it is like i'm destined to use a pair.
The system isn't so much being designed as it is coming together organically.
JX150s will either be in a sealed box -- or more likely a TL -- i have a triangulated design on the books already. Something that drags as much bass out as possible but with close to critical Q. The FE108 are crying out for some sort of low resistance box... because the other elements are mono-pole something that reduces rear output so think cross between an OB and an aperiodic TL. XO at the bottom of FE108eS will be determined by where it starts to roll off, i'm guessing that will be 200 Hz or so. I'll add a 1st order pole in the amp (likely an SE tube amp so this is achieved with a smaller than usual coupling cap). Placement of a single pole on the top of the mid amp determined by how low i figure i can safely XO the ribbon 2nd order (1 pole in a EL84 SE in the same manner as the mid amp -- i have a lovely set of tweeter amp OPTs + a blocking cap in series with the tweeter). XO on the Jordans will be determined by what it takes to get them to blend with the Fostex... with response to 8-10k it should be doable.
At the moment a shape something like the Sonus Faber Stradivaria -- a wide baffle fading back from the middle so that the baffle step loss on the FE108eS is at or below its cutoff. The reverse effect on the upper part of the JX150s response will have to be dealt with in the XO.
This may all also be augmented by a (real) subwoofer utilizing the unused space near the ceiling of my lab downstairs which just happens to have a common wall with the listening room -- 4 or 8 12s or 15s could provide an effortless bottom octave or so.
The best amp we have done so far for bass is a 4W PP tube amp... we'll need a bit more power than that, so further development along those lines is currently indicated, but we do keep trying to find a SS amp with similar finesse.
I'm in no hurry to get this together... and it seems to be coming together on its own and will likely evolve furthr from the current visualization.
dave |
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| m@ |
| quote: | | How come 300hz? I find it a little high. My requirement comes from the fact that I intend to use the same speakers for 2 ch. audio as well as 4.1 or 5.1 ch. HT/AV. |
Because my OB starts to roll of around there. I wanted my big drivers to handle all EQ duty. If the FF85k could handle EQ, I'd probably shoot for 200.
If you're not using them OB, you can go to 200, I would guess. 200 for surround speakers, no problem.
You ever go up to Darjeeling? Man, that's a beautiful place. |
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