8675309 said:
If you use metal cones you will almost invariably have to use steepish passive or an active crossover. This is because of the break-up peaks in the response of the driver itself.
If you want to use a simpler low order crossover, then you have to choose your drivers very carefully.
Now, assuming you have the Fountek you mention, then it can be used low order at around 4.5k. This is cool with the Peerless 4", but what I would do is get another 2 of the Peerless 4" while they are going cheap, and arrange them in an MTM formation. This would help with any excursion problems it might have, and maybe allow you to cross a bit lower to your woofer (say 400). Look to do something on the line of "Blackwood", maybe with the Peerless 4"s operating open back. http://members.optusnet.com.au/~gradds55/ARGOS/blackwood.html
I would then try to find an 8" or 10" with a nice smooth rolloff eg Vifa P21WO (I haven't really got time to go hunting for you, but there are bound to be other good smooth roll-off bass drivers out there)
For low order x-o you basically HAVE to avoid metal cones, there really is nothing you can do about it.
For x-o, I have used the format in the link below with great effect. Its simple, and so long as the drivers suit, it sounds great and is easy to work with.
http://members.optusnet.com.au/~gradds55/SeriesXO/series_cross-overs8b.htm
Other have also found that this approach sounds very nice 😉
http://www.diyaudio.com/forums/showthread.php?s=&threadid=88567&perpage=25&pagenumber=30
8675309 said:
There is nothing wrong with using *that* ribbon with a poly midrange. It is structurally highly dampened (plastic reinforced design), and will give a similar yet cleaner sound (which should blend well using a 1st order because it will span a greater freq. range).
You will have to pad down the tweeter though to match efficiency at crossover.. quite a bit actually (..and frankly this just adds to the similarity with the poly cone). (Note that I specifically would *not* utilize an MTM (or any dual mid) configuration with a 1st order and a fairly high crossover freq. - or you will run into problems.)
You will likely need a fairly high crossover for the tweeter though (say 6-7 kHz - and who knows, 5 kHz may be just as good or better), for modest power handling. Fortunately though the midrange is fairly extended and benign (with out serious break-up problems).
At a crossover of 500 Hz you'll have problems finding a suitable woofer that doesn't need some form of electrical compensation (eq) for baffle step loss. My suggestion is a crossover around 120 Hz (depending on baffle size) with a woofer that is about 3-4db more efficient at this freq. than the midrange. The midrange with an fs around 80 Hz and 3 mm's of linear excursion should have no problem with this low crossover. Alternatively you could go with a "2.5" way crossover - i.e. no highpass filter for the midrange and a slightly less efficient woofer (depending on amplification and wiring configuration).
I'd choose this woofer for several reasons:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-485
1. Its inexpensive
2. Its *about* the right efficiency for one 8 ohm coil. (I'd go the 2.5 route (..depending on how close the woofer is to the floor), which is cheaper for the crossover parts).
3. Its has another 8 ohm coil to allow you to use a sub plate amp with to boost the freq. response to tailor to your room (..if you want to now or latter).
4. Tonally it shouldn't interfere with the basic character of the rest of the system (its a plastic coated paper driver and will sound similar to the poly driver near the crossover).
5. Its fs (and other parameters) are suitable for the application.
Negatives: its a fairly cheap driver and probably has higher non-linear distortion than more expensive offerings. It will also need a notch filter around 2.3 kHz to filter-out the break-up region.
Considering room gain I'd be looking at about a 3.9 cubic foot volume with a vent freq. of 19 Hz. (..a 4 inch interior diameter tube with a length of about 21 inches.) That should give reasonably flat in-room extension to 20 Hz with one 8 ohm coil. It should also give keep the port resonance out of the fundamental passband. *If* there doesn't seem to be enough bass for you then you can always add the plate amp to the other 8 ohm coil. *If* you want a smaller enclosure you can always increase the vent freq. (but try to keep it below 28 Hz), OR you can simply add the plate amp to the other 8 ohm coil and boost away (with a modest increase in non-linear distortion). In fact you don't have to have a vented box at all - you could (more easily) go with a sealed enclosure and again boost the lower freq.s with the second 8 ohm coil (..non-linear distortion would be significantly increased however, BUT that may not be a big deal to you).
A good cheap sub plate amp can be found here:
http://www.mcminone.com/product.asp...ucts&category_name=3831187&product_id=50-6272
Anyway, good luck!😉
ScottG said:
I have done it many times. There is not any audible problem.
I hadn't looked at the sensitivity, but if heavy padding is required it, would mean they could be crossed lower anyway.
tinitus said:My my, that was not well received
Damn, and I felt so good about it ... I will not suggest anything then
Good luck with your project
🙂
tinitus said:
You couldn't resist... Hi again.
Andy Graddon said:
I've tried this myself.. and have found serious audible problems, and modest measurable problems (with smaller mids like here). I've also had problems with commercial loudspeakers that do this (i.e. Dunlavey and Duntech). It could be a listener thing though - some people (like myself) may well be more sensitive to vertical polar radiation. Note that combing will occur and alter the freq. response and will be far less likely to match well with a 1st order crossover - it may however match well with a different order that just happens to be electrically first order, and/or it may pad down an rising freq. response from the MM drivers. A good example of this is the commercial Zu MTM designs - which happens to *substantially* comb where the MM driver's whizers have substantial "peaking", additionally the tweeter does not extend flat for 2 and a half octaves below its crossover (i.e. its not a 1st order design).
In any event - it *IS* complex and it could very well produce an unexpected and unwanted result.
ScottG said:
Well sit down and listen, instead of jumping up and down 😀
The linked series x-o I was talking about generally starts at 6dB roll-off on the tweeter then changes to around 12dB.
I am just trying to come up with something tha might work with the drivers he says he has, ie the Peerless 4" and the Fountek. He also says he wants to use a low order x-o. If low order, he has to stear clear of metal drivers.
With the MRM arrangement, I agree that the lower he can cross with his low order x-o the better. It just comes down to how much the ribbon can take. With padding, he may be able to go as low as say 3k.
One of those Peerless 4"s by itself isn't going to work really well unless crossed pretty high from the bass unit though, which leads to using a pair of each, so the logical arrangement is MRM.
I guess it comes down to what compromises he wants to accept.
What about this combo. I am game to change the mid.
What about 2 of these MRM arrangement. My software tells me that with 2 of these I can get a sensitivity of around 94 db
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-370
If I implemented 2 of these It tells me I would get around 94 db also
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-370
So the layout would be MRMWW
This will get my sens a little closer to the ribbon and solve pad problem. Now on the down side the 5 incher states that they are usable up to 4500hz. I am not sure if this is true or not. If I did a simple 1st order at 400 and 4000 would the design be usable?
What about 2 of these MRM arrangement. My software tells me that with 2 of these I can get a sensitivity of around 94 db
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-370
If I implemented 2 of these It tells me I would get around 94 db also
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-370
So the layout would be MRMWW
This will get my sens a little closer to the ribbon and solve pad problem. Now on the down side the 5 incher states that they are usable up to 4500hz. I am not sure if this is true or not. If I did a simple 1st order at 400 and 4000 would the design be usable?
What about something simple like this?
http://www.madisound.com/catalog/product_info.php?cPath=45_241_308&products_id=275
and the Fountek ribbon?
I already have the ribbon so I dont want to can it.
I am not looking for huge sound I just want a good sound.
Maybee even use this enclosure?
http://www.madisound.com/catalog/PDF/fostexdrivers/fe208ez.pdf
http://www.madisound.com/catalog/product_info.php?cPath=45_241_308&products_id=275
and the Fountek ribbon?
I already have the ribbon so I dont want to can it.
I am not looking for huge sound I just want a good sound.
Maybee even use this enclosure?
http://www.madisound.com/catalog/PDF/fostexdrivers/fe208ez.pdf
tinitus said:Well, that was a bit grumpy
When you want 6db, you will have to select drivers very carefully ... and to me it is furthermore an indication that you dont know much about xo filter
I would take a different approach
Get a pair of those very nice 12" Fostex FW305, they are on sale now
Fore mids you could use the Fostex FF125K, cost very little
And the Fountec should be ok with this
Low xo point should be more like 500hz or more, and upper xo point well above 3khz, and you should be able to manage a "6db" filter
And think of the nice efficiency 😎
Make life easy on yourself.. ditch your current plans but keep your tweeters and use them in this design:
http://www.htguide.com/forum/showthread.php4?t=25932
It should be a design you can live with for the rest of your life - and be every bit the HiFi speaker, yet not cost a fortune. (..those mids in particular while more expensive - should be extraordinary.. FAR beyond the quality of most drivers anywhere near their price - especially in that "open back" config..)
Just a suggestion (but its my last).🙂
http://www.htguide.com/forum/showthread.php4?t=25932
It should be a design you can live with for the rest of your life - and be every bit the HiFi speaker, yet not cost a fortune. (..those mids in particular while more expensive - should be extraordinary.. FAR beyond the quality of most drivers anywhere near their price - especially in that "open back" config..)
Just a suggestion (but its my last).🙂
ScottG said:
I have to agree with Scott. Trying to use the Fountek ribbon with the 4" AND using a low order x-o is always going to cause issues because the low order x-o forces you to cross the ribbon high. The speaker is compromised right from the start !!
With being intending to be rude (am I ever 😉 ), it seems to me that you haven't done much, if any x-o design, and that you really aren't sure how to proceed in even choosing drivers that will work together. If this is actually the case, then would do FAR better to go with an established design.
His suggested speaker is definitely one to consider.
8675309 said:
So you want to make a party with $300 in you pocket. Good to know w/ what we are dealing with. But you don't say much about the woofer size.
tinitus said:
Sure the Fostexs are nice. Did you think about it 8675309? They are paper but sure is a good driver. The same with the 10" SEAS-Dynaco's (SEAS A26RE4-H1411 Dynaco-A25)/(25-Fs/89dB) .
Maybe they are over priced for you? Some feedback is needed here... or for the size?, I just don't know your opinion.
http://www.madisound.com/catalog/product_info.php?manufacturers_id=131&products_id=302
and (fw305.pdf here)
Andy Graddon said:
Andy Graddon said:
Andy Graddon said:
to chech this driver go here,
http://www.seas.co.uk/pdf/h1316.pdf
Other polycones that I would definitely consider would be for a 8" woofer w/ very good Fs or SPL, maybe using them in push-pull mode, for good cabinet makers, and having like this a very strong bass line:
P21WO20 8" woofer (28-Fs/91dB)
http://www.madisound.com/catalog/product_info.php?manufacturers_id=153&products_id=1111
http://www.madisound.com/catalog/PDF/p21wo20-08.pdf
P21WO39 8" Polypropylene (26-Fs/88dB)
http://www.madisound.com/catalog/product_info.php?manufacturers_id=153&products_id=1112
http://www.madisound.com/catalog/PDF/p21wo-39-08e.pdf
these two would be a good match for your 3 way, what do you think about what I said, so others can also have their mind set.
Ps: The problem I see with the Daytons is if there are specs for it with frequency response curves, they don't show.
Andy Graddon said:
what I meant to type, and thought I had when I read it through, was...
""Without intending to be rude""
http://www.madisound.com/catalog/pr...products_id=302
and (fw305.pdf here)
One of the designs recommended had s 4th order slope of 2000 with the ribbon.
This design
http://www.troelsgravesen.dk/W15_Neo3.htm
The Fostex 12 looks flat out to 2000 on axis. Could I keep the Neo tweeter design from the W15_Neo3 and focus on a 4th order for the fostex 12? And have a decent 2 way?
This is where I am getting confused. In car audio I run active setups so I really don’t have to mess with the xover designs. If I want to use the ribbon in a 3 way or 2 way, I should focus on using metal drivers with higher xover slopes? The sens needs to match up or be as close as possible? It is possible to use the ribbon with poly woofers but I need to use steep slopes? It is ok to use a 1st order slope with paper drivers like the fostex?
Sorry for all of the questions but many of the post contradict each other.
I am not looking for a party speaker; the Dayton recommendation I made was a quick design or feeler for your opinions. I focused only on the sens of the drivers to get them close to a match with the tweeters.
and (fw305.pdf here)
One of the designs recommended had s 4th order slope of 2000 with the ribbon.
This design
http://www.troelsgravesen.dk/W15_Neo3.htm
The Fostex 12 looks flat out to 2000 on axis. Could I keep the Neo tweeter design from the W15_Neo3 and focus on a 4th order for the fostex 12? And have a decent 2 way?
This is where I am getting confused. In car audio I run active setups so I really don’t have to mess with the xover designs. If I want to use the ribbon in a 3 way or 2 way, I should focus on using metal drivers with higher xover slopes? The sens needs to match up or be as close as possible? It is possible to use the ribbon with poly woofers but I need to use steep slopes? It is ok to use a 1st order slope with paper drivers like the fostex?
Sorry for all of the questions but many of the post contradict each other.
I am not looking for a party speaker; the Dayton recommendation I made was a quick design or feeler for your opinions. I focused only on the sens of the drivers to get them close to a match with the tweeters.
Cost is really not the problem. My budget for this set of speakers is $1000. This is only because I have too many other projects going on. I would like to use the Ribbons I have if possible. I really like the idea of a single driver like the fostex 12 and the ribbon.
As far as the woofer question. I am not biased to woofer size. I like good clean bass regardless of size. This is a temp set of speakers, until I get my new house built, which will house 2 or 4 IB 15’s in the ceiling and consist of smaller 2 ways. The set I am building now will eventually go to my hunting camp.
As far as the woofer question. I am not biased to woofer size. I like good clean bass regardless of size. This is a temp set of speakers, until I get my new house built, which will house 2 or 4 IB 15’s in the ceiling and consist of smaller 2 ways. The set I am building now will eventually go to my hunting camp.
8675309 said:
Do you like the fostex better? It will play in a very decent configuration for a 2-way or a 3-way with your very nice mids you already have, you to choose.
For a 2 way you can have like a 1.order on the woofer and a 3.order on the tweeter and reverse one of them for phase alignement. Some people say a 12" will beam (highest recommended frequency is 1.73KHz), I don't know from experience. If that's an obstacle you always have the 3-way waiting for you, or since you have them (mids) you can go the other way around.
Note: Also it's possible to simulate the tweeter in another configuration.
True, but we should point out that those SA Tweeters are famously tough- and expensive! A regular ribbon the size being discussed won't cross at 1000hz for long..
As I recomended the 12" Fostex I better speak now
I have thought about the same, to make it a 2way with your Fountec
From a technical point of view it may not be THE perfect solution
BUT it may very well give the best end result, given the situation
The Fostex seems to be a very well behaved 12" ... you know, there are people using a 12" much higher
Further more it will have the SPL to match your Fountek, almost
I bet that with a 12db filter on the woofer around 2khz, the 12" Fostex will roll off with 24db acoustical slopes, or close to at least
This means that you may be able to copy the Fountec 24db filter from TroelsGravesen, which I suppose is also acoustical 24db
Offcourse you will have to retune the padding, or maybe even leave it out
The 12db woofer filter should be fairly "easy" to tune to match the tweeter filter
Yeah, I think its worth a try ... and you may have something special that you will never part from
It may not be perfect for the most delicate classical music, but might be quite perfect for jazz, rock and blues
😎
I have thought about the same, to make it a 2way with your Fountec
From a technical point of view it may not be THE perfect solution
BUT it may very well give the best end result, given the situation
The Fostex seems to be a very well behaved 12" ... you know, there are people using a 12" much higher
Further more it will have the SPL to match your Fountek, almost
I bet that with a 12db filter on the woofer around 2khz, the 12" Fostex will roll off with 24db acoustical slopes, or close to at least
This means that you may be able to copy the Fountec 24db filter from TroelsGravesen, which I suppose is also acoustical 24db
Offcourse you will have to retune the padding, or maybe even leave it out
The 12db woofer filter should be fairly "easy" to tune to match the tweeter filter
Yeah, I think its worth a try ... and you may have something special that you will never part from
It may not be perfect for the most delicate classical music, but might be quite perfect for jazz, rock and blues
😎
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