ScottG said:
Much better.
Treble:
http://www.raalribbon.com/products_flatfoil_140-15.htm
Midrange (4 drivers per loudspeaker):
http://www.partsexpress.com/pe/showdetl.cfm?Partnumber=264-848
Bass driver (large vented enclosure 6 cu-ft 25 Hz tunning w/ 6 inch vent):
http://www.supravox.fr/anglais/haut_parleurs/285_GMF.htm
(top-down):MMMMTW
Two-box system. One box for the midbass. A smaller adjustable box for the mid-and-tweeter.
Avg. eff. 91 db 8 ohms.
Scott, your idea is indeed very interesting but also very special and non-standard ... strigtly "by the book" it seems flawed in several areas, so as long as it havent been tried and carefully tested I wouldnt be so persistent about it ... but ok inspiration
Personally I keep coming back to AE TD15S, and I am more and more convinced that it may be THE ideal 15" woofer fore closed box or most optimal with very little tradeoffs... Fs 22.8 / vas 467 / Qts 0.37 / Xmax 14mm / 93.4db ... and built like a pro driver, well maybe "S" stands fore "studio"
But pjpoes want it smaller ...
A smaller design ?
Could be B&C 6NDL38
http://www.bcspeakers.com/index.php...izione=44&prodotto=194&id_descrizione_prod=51
It has nice Xmax, should work in about 7liter, lows rolls off nicely by itself with -6db around 90hz(limited excursion)
Tweeter could be anything
Well, woofers may have to be placed on the sides, driven by plateamp
http://www.mach5audio.com/zen/index.php?main_page=product_info&cPath=65&products_id=187
One on each side, dont need much volume to go low, 10-15 liter each driver
Should take som "beating" without distortion
Could be B&C 6NDL38
http://www.bcspeakers.com/index.php...izione=44&prodotto=194&id_descrizione_prod=51
It has nice Xmax, should work in about 7liter, lows rolls off nicely by itself with -6db around 90hz(limited excursion)
Tweeter could be anything
Well, woofers may have to be placed on the sides, driven by plateamp
http://www.mach5audio.com/zen/index.php?main_page=product_info&cPath=65&products_id=187
One on each side, dont need much volume to go low, 10-15 liter each driver
Should take som "beating" without distortion
Attachments
I thought that I read where Bill Woods was using the little B&C 6 in a horn of his for a nice 2 way combo. He said that it was a pretty darned nice driver. That in a half horn and a good compression driver with a good waveguide/horn on top, and you would be set with a smallish high efficiency setup.
ScottG said:
I think PJ baulked at the 600 liter box volume not at the price.
tinitus said:But pjpoes want it smaller ...
tinitus said:
Lets give PJ a chance to contribute and inform us what his idea of a comfortbale box size. Based on his understandable objection to the 600 liter sub I would asume (only assume) that PJ would be expecting somthing on the lines of a "traditional" floor standing 3 ways speaker.
A box that would occupy about 1.3-1.5 sq. ft of floor space and be about 3.5-4 feet tall.
tinitus said:
what about this 10" woofer? 7db down at 20Hz when combined with a PR in 35 liters. 2 woofer and 2 PRs in 70 liters might be "just the ticket".
from http://ldsg.snippets.org/vendors/peerless.php quote...
The 830452 10" XLS woofer. With a very low Qts value (0.17), it's only suited for use in small vented or PR enclosures. Most who've used it have had success using its matching 830481 10", 400 gram PR in a 35 liter (1.24 cu.ft.) box. This yields an EBS alignment (see discussion of enclosure types in the Introduction above) with F3=78 Hz, but which is only 7 dB down at 20 Hz.
tinitus said:
Actually that wasn't really the intent of my last posts.. at all.
The one with your quote was to address questions you had. The next one with pjpoe's quote was to address some of his concerns - in relation to his original requirements.
The latest was to further "flesh-out" pjpoe's requirements - to a degree. More importantly however it was to address the trend of recommendations that seemed NOT oriented on what pjpoe's wanted, but rather on what *others* wanted.
If it seemed that I was persistent with the design I recommended, well .. that wasn't the intention (..rather it was used for continuity in my posting). Really, the only thing that would make me happy with regard to this thread is that pjpoes gets what he wants (..not necessarily what I or anyone else would want).
tinitus said:Seems I just got it wrong then, my appology
What does pjpoe want? I dont know, do you ? does he ?
Hell, I am going to build one fore myself but I have so many ideas in my head that I cant decide on anything, it all takes different directions and I dont know which one to choose
So'kay.
Really what you need to do is start your own thread on the subject - (in that I'm sure your needs will be different).
I do think (finally) that pjpoe has expressed rather well *most* of what he wants. (..so I think that if anyone reads his participation in the thread fully they will in fact have a good idea of what he is looking for.) The real "move forward" then is trying to apply that expression to a suggestion that actually complies with it.
The foundation for that suggestion is the midrange - specifically a HiFi driver mid. That is what *he* wants. The best suggestion I could make is a 4 driver line of the Tangband titanium foil drivers.. but there are LOTS of others. Certainly Skanning comes to mind, as does the Accuton C173N-T6-96.
For woofers there are any number of drivers worthy of mention, BUT they require an efficiency to match the rest of the system's design, so for the most part their consideration is subservient.
The tweeter (in particular) is often the most "subjective" driver in the grouping, but its also the most "pliable" (in that you can tailor its response far more than the other drivers in a passive crossover). It then too is a driver to be considered latter in the process.
So I guess the question is:
- which *HiFi* mid(s) would you recommend for him, in what design context, and why?
ScottG said:
The Tangband mid looks nice especially since it is cheap enough to be used in arrays of 4 (or even in a 2x2 push-push array). How does the Tangband compare to the FR125/WR125? They are proiced about the same.
beyond that I think PJ should consider either 2 x ScanSpeak/Seas/Focal 15-16cm mids in a push-push/MTM
or go wide range and consider a 18-20cm Supravox 215/Veravox7/Fostex207/etc..
As far as the bass is concerned we know that PJ found 600 liters to be a bit too big so we need to first fix what size PJ finds acceptable.
navin said:
From what I've gathered from other sources the Tangband foils, excepting limitations in power/excursion and efficiency, are as good as any driver used for the midrange (sound-wise, not measurement-wise though they measure very well in several respects), and better than all but a *very* few. Pjpoes himself could give you a better idea though (since he actually has them). Of course you could also use the driver in a MM combination (MTM or otherwise) in *parallel* and provided the amplifiers will double its output with a halved impedance you'll still be up at around 91-92 db with base impedance slightly higher than 4 ohms (instead of 8). You would have to be a bit more concerned with excursion at that point.. so its likely you would be looking at a 3-way crossover then.
I probably wouldn't recommend focals for the midrange - to me the latest "glass" drivers sound compressed (..but their tweeters by contrast sound better to me). Dido for the Magnesium Seas that I've heard (..but I haven't heard the Nextel versions). The Scan Speak 15W8530K00 could work - but its pricey. There is also the Peerless 830882, but it has some linear "hash" at the top of its range.
The fullrange fostex's, Veravoxes, Supravoxes, ects. don't really comply with the HiFi driver sound in the midrange.
The VISATON AL130 M is also a possibility (..I discount the TI 100 and the Jordan 5 inch because they are comparable to the Tangband at a higher price).
Hi guys, sorry I haven't responded in a little bit. Ok so maybe we could talk about what drivers I have. I could even post some idea's I have crossover wise.
As for dimensions, I have a 4.5 cubic foot ported subwoofer I built using a TC Sounds 3000 12" woofer. Yes its only one, and it was really designed for the .5 channel of the surround system. However, given the bass limits of my main speakers, it does also serve as the bass speaker for the whole system. However, I wouldn't mind having full extension in the main speakers as well, so that the single sub doesn't have to do both. Some may disagree, but what I'm finding so far is that Bass management in both my Boston Acoustics AVP-1 processor (A sherwood clone of sorts) and in my Meridian is pretty poor. Poor in that I don't think its particularly intelligent in how it chooses to send bass to the sub.
Ok as for what I would accept, no more 4.5 cubic foot enclosures, I don't want two more of those. Tall towers are ok, but less than 60 inches would be nice. As for width, well less than 12 inches for sure, but less than 10 would be better if I could. This will of course be partly dictated by driver choice.
Some have suggested a separately powered bass speaker, subwoofer, whatever you want to call it, located in the lower section of the tower, a near by second enclosure, or side mounted. I actually kind of like the side mounted idea. That would take care of bass, however, I'm then wondering about how high to run these. Most suggestions are to use an actual purpose built subwoofer driver. For the sake of argument, lets say I did something like the GR Research SW-12 (Which gives the option of servo control and thus lower distortion), it was recommended that I don't run it much above 150hz or so.
Ok for the next part there is a wide range of choices. We are talking a midbass driver that just has to go from 150hz to either a midrange driver, or...the tweeter. This gets back to the original post really, how many drivers and crossover points do I want here. I like scan-speak drivers a lot, but it was suggested that I might find Usher Audio's drivers a nice cheaper alternative. So one idea I have had is to use two Usher Audio 8945P midbass drivers crossed over around 1.6-1.8khz to my Focal TC120TDx tweeters. implemented right I love that tweeter, wrong, and it does rip your head off.
Then you have the idea of having multiple drivers cover the range from 150hz up to 1.6khz or so, in a sort of cascading fashion. Increase the amount of driver displacement as you go down through the octaves (i.e. 2.5 way, 3.5 way, etc.). I then started considering 3 or 4 of the Usher midbass drivers. Then I was thinking, if I'm doing this, does it really make such a good midrange driver, maybe something with a cleaner midrange and even lower distortion between 300hz and 1.6khz would be better. So now again things get more complicated. Scan-speak has a good revelator series midrange, but its quite expensive, I'm not sure I want to spend that much on that driver. Dayton has the reference midrange which isn't bad, but I've been told to avoid crossover points between 400hz and 600hz, and also to avoid crossover points in the 3-5khz range (Though that seems to be a very popular crossover point). The TB Titanium cone full range has an impressively flat response and low distortion where it matters. I hadn't thought of using it as a midrange, but its not such a bad idea. It also might be an interesting combination with the Focal tweeter, but where to cross it over.
Now I also have a pair of Focal W-cone midbass drivers. These are the 6W 4254 midbass drivers. They are similar in specs to the 4311B, but with a larger vas and lower FS, but also lower xmax. I am currently using these in a two way tower of 1.85 cubic feet, crossed at around 1.8khz, and 4db's of baffle step compensation applied. These sound quite good, but have an efficiency of 1 watt at 1 meter around 82db's or so. I can't get any more of these drivers but I can of course buy the 4311B's, and I was just informed by Eliot at Zalytron that he got some odd buyout drivers that he is having measured at Orca. They will be 100 dollars each and we are both expecting them to be similar to the 4311B. I also have a pair of Focal 4311B's in my center channel, crossed to a TC90td5. I could switch these drivers (The crossover is in need of rework anyway) and use them as midranges, then use something else as midbass drivers.
Anyway, I think its quite clear, I don't know what I want. I know what I want in Theory, I know what speakers I have heard and like, but I just am not sure what I want to build. It just makes sense that more drivers, while more complex, is going to sound better from the standpoint of lower distortion at a given output. It also makes sense that using drivers in their optimal range, and limiting that range, will allow them to perform their best with the least amount of distortion.
GR OB-7
This is the OB-7 from GR-Research. This could be an example of a design similar to what I am picturing in my head. While he isn't using a 3.5 way design, as I had originally thought, he is still using more displacement as you go down in frequency, with a separate dedicated subwoofer driver for the low bass. I had even thought about just doing this kit, but Zaph's measurements of the drivers used in it did not impress me. I can't help but think that better drivers using a similar topology might offer me something better, and for the same kind of money.
Now to really throw a monkey wrench in the works, there is of course the idea of going with high efficiency drivers. I mean, something like the Everest from JBL could be DIYed, its really just a 3.5 way design. I could purchase two 12" or 15" woofers and run them up to 1-1.2khz or so. Directivity isn't often a huge issue with even a 15" at this frequency. Yes at 45 degrees off-axis it becomes very directional above 400hz, but the measured listening axis for me is generally less, so maybe I need to toe them in a little more. Then a horn tweeter could be used for the highs. A ribbon tweeter or even BG planar tweeter array could be used as well, all giving decent sound and high efficiency, with relatively low distortion. My biggest problem here is that two 15" JBL drivers (For example) will require what, like 6 cubic feet, will be huge, and will still suffer from off-axis response problems, narrowing the listening window to maybe 15 degree or so.
I know I know, I think too much. Ok well I can also post some ideas along with crossover schematics that I have been playing around with.
As for dimensions, I have a 4.5 cubic foot ported subwoofer I built using a TC Sounds 3000 12" woofer. Yes its only one, and it was really designed for the .5 channel of the surround system. However, given the bass limits of my main speakers, it does also serve as the bass speaker for the whole system. However, I wouldn't mind having full extension in the main speakers as well, so that the single sub doesn't have to do both. Some may disagree, but what I'm finding so far is that Bass management in both my Boston Acoustics AVP-1 processor (A sherwood clone of sorts) and in my Meridian is pretty poor. Poor in that I don't think its particularly intelligent in how it chooses to send bass to the sub.
Ok as for what I would accept, no more 4.5 cubic foot enclosures, I don't want two more of those. Tall towers are ok, but less than 60 inches would be nice. As for width, well less than 12 inches for sure, but less than 10 would be better if I could. This will of course be partly dictated by driver choice.
Some have suggested a separately powered bass speaker, subwoofer, whatever you want to call it, located in the lower section of the tower, a near by second enclosure, or side mounted. I actually kind of like the side mounted idea. That would take care of bass, however, I'm then wondering about how high to run these. Most suggestions are to use an actual purpose built subwoofer driver. For the sake of argument, lets say I did something like the GR Research SW-12 (Which gives the option of servo control and thus lower distortion), it was recommended that I don't run it much above 150hz or so.
Ok for the next part there is a wide range of choices. We are talking a midbass driver that just has to go from 150hz to either a midrange driver, or...the tweeter. This gets back to the original post really, how many drivers and crossover points do I want here. I like scan-speak drivers a lot, but it was suggested that I might find Usher Audio's drivers a nice cheaper alternative. So one idea I have had is to use two Usher Audio 8945P midbass drivers crossed over around 1.6-1.8khz to my Focal TC120TDx tweeters. implemented right I love that tweeter, wrong, and it does rip your head off.
Then you have the idea of having multiple drivers cover the range from 150hz up to 1.6khz or so, in a sort of cascading fashion. Increase the amount of driver displacement as you go down through the octaves (i.e. 2.5 way, 3.5 way, etc.). I then started considering 3 or 4 of the Usher midbass drivers. Then I was thinking, if I'm doing this, does it really make such a good midrange driver, maybe something with a cleaner midrange and even lower distortion between 300hz and 1.6khz would be better. So now again things get more complicated. Scan-speak has a good revelator series midrange, but its quite expensive, I'm not sure I want to spend that much on that driver. Dayton has the reference midrange which isn't bad, but I've been told to avoid crossover points between 400hz and 600hz, and also to avoid crossover points in the 3-5khz range (Though that seems to be a very popular crossover point). The TB Titanium cone full range has an impressively flat response and low distortion where it matters. I hadn't thought of using it as a midrange, but its not such a bad idea. It also might be an interesting combination with the Focal tweeter, but where to cross it over.
Now I also have a pair of Focal W-cone midbass drivers. These are the 6W 4254 midbass drivers. They are similar in specs to the 4311B, but with a larger vas and lower FS, but also lower xmax. I am currently using these in a two way tower of 1.85 cubic feet, crossed at around 1.8khz, and 4db's of baffle step compensation applied. These sound quite good, but have an efficiency of 1 watt at 1 meter around 82db's or so. I can't get any more of these drivers but I can of course buy the 4311B's, and I was just informed by Eliot at Zalytron that he got some odd buyout drivers that he is having measured at Orca. They will be 100 dollars each and we are both expecting them to be similar to the 4311B. I also have a pair of Focal 4311B's in my center channel, crossed to a TC90td5. I could switch these drivers (The crossover is in need of rework anyway) and use them as midranges, then use something else as midbass drivers.
Anyway, I think its quite clear, I don't know what I want. I know what I want in Theory, I know what speakers I have heard and like, but I just am not sure what I want to build. It just makes sense that more drivers, while more complex, is going to sound better from the standpoint of lower distortion at a given output. It also makes sense that using drivers in their optimal range, and limiting that range, will allow them to perform their best with the least amount of distortion.
GR OB-7
This is the OB-7 from GR-Research. This could be an example of a design similar to what I am picturing in my head. While he isn't using a 3.5 way design, as I had originally thought, he is still using more displacement as you go down in frequency, with a separate dedicated subwoofer driver for the low bass. I had even thought about just doing this kit, but Zaph's measurements of the drivers used in it did not impress me. I can't help but think that better drivers using a similar topology might offer me something better, and for the same kind of money.
Now to really throw a monkey wrench in the works, there is of course the idea of going with high efficiency drivers. I mean, something like the Everest from JBL could be DIYed, its really just a 3.5 way design. I could purchase two 12" or 15" woofers and run them up to 1-1.2khz or so. Directivity isn't often a huge issue with even a 15" at this frequency. Yes at 45 degrees off-axis it becomes very directional above 400hz, but the measured listening axis for me is generally less, so maybe I need to toe them in a little more. Then a horn tweeter could be used for the highs. A ribbon tweeter or even BG planar tweeter array could be used as well, all giving decent sound and high efficiency, with relatively low distortion. My biggest problem here is that two 15" JBL drivers (For example) will require what, like 6 cubic feet, will be huge, and will still suffer from off-axis response problems, narrowing the listening window to maybe 15 degree or so.
I know I know, I think too much. Ok well I can also post some ideas along with crossover schematics that I have been playing around with.
pjpoes said:
PJ, you got a budget for the drivers? per channel?
Why do you want to cross the T120Tdx so low. It really should be XOed a bit higher.
Given your SPL needs let's assume you'd need 4 x 5" or 2 x 6" woofers to cover 150Hz-3kHz something like this but with 2 more 5" woofers in the rear. The 130F1 tested by Zaph is probably the smoothest of the Aurum Cantus midbasses.
http://www.aurumcantus.com/aurumcantus-download/gallery/index_gallery_SUPREME_pic01.htm
Use the same 10" woofer in the Supreme, mated to 4 5" woofers, and XO above 3kHz at 24db/oct so you can use a ribbon tweeter like the RAAL or LCY 130.
If your budget permits another alternate is an all Eton system using their 11" woofer (similar to the Aurum woofer), 5" midbass (which is capable to 4kHz) and Heil tweeter.
woofer:
2 x http://www.aurumcantus.com/aurumcantus-midwoofer/index_midwoofer_ac250_75c2c.html
or
2 x http://www.eton-gmbh.de/dlstream.php?FileId=63
midbass:
4 x http://www.aurumcantus.com/aurumcantus-midwoofer/index_midwoofer_ac130_f1.html
or
4 x http://www.eton-gmbh.de/dlstream.php?FileId=57
Tweeter
1x http://www.solen.ca/v1/pics/raal/70-10.jpg
or
1 x http://www.eton-gmbh.de/ShowPage.php?PId=19&LangId=2&PHPSESSID=778286d478d6cd970429d11a957ac0b5
ScottG said:On the other hand he seemed to balk at the price of the Supravox.. Not its cost, but rather its value. To that, all I can add is that there are few if any alternatives to the driver; the 285 is exceedingly *unique*. If you can find a similar driver for less, let me know!
Hello Scott!
The answer comes a bit late, but the old WIGO 12" drivers (sometimes sold as "Bauer"´) have been used successfully in BR. As far as I know you don´t get the Supravox in the US, so there would be shipping cost in both cases. The price difference is not high, however.
First, as for why I'm crossing the tweeter over so low. I like it that low, having experimented with different crossover points, I find that sounds best. The tweeter just does a better job handling the frequencies between 1.5khz and 3khz. A lot of people who were attempting to clone JmLabs Utopia speakers found that their clones sounded much better if they didn't clone them crossover wise and used different crossover points. A very common trend has been crossing the tweeter over at below 2khz. Also, the crossover point has to be lower the the frequency of the distance of the midpoint between the two mid bass drivers and the tweeter. That means for a 3khz crossover point the midpoint of the tweeter and the mid-point of the midbass have to be less than 4" apart from each other for good integration. Thats a lot harder to do than it would seem as the flange of the tweeter and dimensions of the midbass driver prohibit that. Mine are currently mounted almost as close as is physically possible and they are 6.5" apart center to center. Another advantage of the low xo point is that the tweeter will not be directional at 2khz or 3khz, but most midbass drivers are. This means that the response won't change over a much wider listening axis.
I'm not a fan of push pull or isobaric midrange loading. It adds no additional output, at least in theory it should not. It's debatable if it lowers distortion at all. It creates a more diffused and IMO less accurate sound stage when it's working in the midrange. For those reasons, I just don't understand the point of adding them, it just increases cost with no appreciable benefits.
Lets see, as for budget, I guess I don't have one for the moment. That doesn't mean unlimited, it just means, lets see how cheaply we can get this Statement design together. I mean, I keep looking at those 4" titanium midrange drivers from Visaton. They measure great, look great, but....they are really expensive for what they are. Still, they aren't really that much more than other things I have looked at, and they seem to be a really great driver. None the less, the TB W4 titanium full range driver looks like a great alternative for considerably less. In fact, so much less that I could go with two instead of one, and then have lower distortion. Two of these in a MTM with the focal tweeter at the center and one or two decent bass drivers for down low could make a nice combination. For good bass drivers there is a whole range of possibilities. The Dayton Reference 8" or 10", the Eton 8", even a GR SW-12 servo driven could have the output, and really low distortion.
The more I measure the Focal 6W midbass drivers I have, the more I think there just isn't anything that great about them. I'm thinking more and more that I don't want to use them as a midrange. Alternative drivers will have lower distortion I think, and probably a smoother response.
Ok one last thing, now I have heard ribbon tweeters that I liked, so I don't want to make a big blanket statement about them. However, here is my thing, they don't measure well, the frequency response is all over the place, and the distortion is much higher than a dome unit. On top of that, they are expensive. I was looking at Raven the other day, but you know what, even those don't measure that great, at least not for the very high price. As for an alternative to a dome, I've been told to seriously consider the BG Neo 3 tweeter. I haven't heard one yet, but was told that it is a superior tweeter to the Focal I'm currently using. Given its low price, I wouldn't mind finding that out. Also, the Neo-8 could be used as a sort of upper midrange. They could only be taken down to say 700hz or so, but still, might be another option. Again though, how many ways is enough to achieve my goal.
I'm not a fan of push pull or isobaric midrange loading. It adds no additional output, at least in theory it should not. It's debatable if it lowers distortion at all. It creates a more diffused and IMO less accurate sound stage when it's working in the midrange. For those reasons, I just don't understand the point of adding them, it just increases cost with no appreciable benefits.
Lets see, as for budget, I guess I don't have one for the moment. That doesn't mean unlimited, it just means, lets see how cheaply we can get this Statement design together. I mean, I keep looking at those 4" titanium midrange drivers from Visaton. They measure great, look great, but....they are really expensive for what they are. Still, they aren't really that much more than other things I have looked at, and they seem to be a really great driver. None the less, the TB W4 titanium full range driver looks like a great alternative for considerably less. In fact, so much less that I could go with two instead of one, and then have lower distortion. Two of these in a MTM with the focal tweeter at the center and one or two decent bass drivers for down low could make a nice combination. For good bass drivers there is a whole range of possibilities. The Dayton Reference 8" or 10", the Eton 8", even a GR SW-12 servo driven could have the output, and really low distortion.
The more I measure the Focal 6W midbass drivers I have, the more I think there just isn't anything that great about them. I'm thinking more and more that I don't want to use them as a midrange. Alternative drivers will have lower distortion I think, and probably a smoother response.
Ok one last thing, now I have heard ribbon tweeters that I liked, so I don't want to make a big blanket statement about them. However, here is my thing, they don't measure well, the frequency response is all over the place, and the distortion is much higher than a dome unit. On top of that, they are expensive. I was looking at Raven the other day, but you know what, even those don't measure that great, at least not for the very high price. As for an alternative to a dome, I've been told to seriously consider the BG Neo 3 tweeter. I haven't heard one yet, but was told that it is a superior tweeter to the Focal I'm currently using. Given its low price, I wouldn't mind finding that out. Also, the Neo-8 could be used as a sort of upper midrange. They could only be taken down to say 700hz or so, but still, might be another option. Again though, how many ways is enough to achieve my goal.
pjpoes said:
I have seen nothing to prove that 2 mids would have lower distortion than 1 mid, when keeping within the power range of 1 mid ... sure thing, 2 drivers can take more power than 1
Raven may not measure well, or better than other ribbons, but from a reliable and critical source I trust who tested a number of famous ribbons, Raven simply sounds fantastic but like other ribbons it dont like to reproduce too much mids, nor do they take much power either ... VERY thin foil
Wow, after looking at the OB design of that GR-OB7 that gave me an idea. I had wanted to use an OB design for the AV mains that I am building but because of necessity they will have to be placed next to the back wall I thought that back reflections would be a problem. THe GR OB7 seems to use an approach that might solve this problem to a great degree.
I have got several 3D concept models worked up but I think that I want to stay simple and use some drivers that I already have in a three way design with about 1 db of BSC. So I've got this design which I really like the looks of. A hybrid OB with 8 inch mid/bass and 12 inch woofer in a vented or aperiodic alignment.
This is picture of the idea without many of the bass module parts finished. I have a limitation of 40 inches tall due to my movie screen. But I wonder what something like this scaled up a bit and using pro drivers for higher sensitivity would do for PJ.
I think the open top cabinet makes the thing look like it is not so big and massive. This particular design has about 2.5-3 cubic foot bass module depending on wall thickness.
Finally I think I have a design which if implimented with state of the art drivers and cabinet construction could out Watt the Puppy.
I have got several 3D concept models worked up but I think that I want to stay simple and use some drivers that I already have in a three way design with about 1 db of BSC. So I've got this design which I really like the looks of. A hybrid OB with 8 inch mid/bass and 12 inch woofer in a vented or aperiodic alignment.
This is picture of the idea without many of the bass module parts finished. I have a limitation of 40 inches tall due to my movie screen. But I wonder what something like this scaled up a bit and using pro drivers for higher sensitivity would do for PJ.
I think the open top cabinet makes the thing look like it is not so big and massive. This particular design has about 2.5-3 cubic foot bass module depending on wall thickness.
Finally I think I have a design which if implimented with state of the art drivers and cabinet construction could out Watt the Puppy.
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tinitus said:
The idea of two mids having lower distortion than one has to do with using the two mids within their lowest distortion range for a larger volume. Less compression distortion is one example of this, but actually, I have measured distortion enough to see that it rises with level before the onset of what most people would call compression distortion. I mean, if THD is lets say less than .3% from 70db's to 100db's, then rises from 100-105db into the .5 or even 1% range, that isn't really enough to be caused by compression, compression distortion typically, as I understand it, is the exponential rise which would be like 10-20-30% and rising very quickly, lets say after 105 dbs. Also, as I understand it, it should be the point where output doesn't increase much or at all with increased amplifier power, but distortion does rise. So when I said lower distortion, I meant that you would have a broader range where distortion was at its lowest. I wasn't expecting to have this mid go from .3% to .1%, just stay below .3% over a broader range.
I'm not saying I will never use a Ribbon tweeter, its just that I want to hear one before I commit to buying. They are very expensive and don't measure well. While I will be the first to say I don't believe we can measure everything we can hear, that doesn't mean that measurements of things we can hear are wrong. Now the Raven has the smoothest frequency response to around 10-15K I have seen, but its still not on par with the dome units. The LCY units are terrible, I mean, I haven't heard one yet to know what this would sound like, but the measurements are all over the place. If you tame its frequency response problems it also becomes very inefficient, which would defeat one of the reasons I would want to use one.
Anyone explain to me why when I parallel two of the TB Ti drivers together (Efficiency is rated at around 87db's I believe), I get 97db's efficiency used as a midrange. It should be 90 right, maybe a few more, 92-93 at the most given the response shaping, but 97 seems way too high. I put together a design using two Peerless HDS 8" midbass drivers, two TB Ti 4" midrange drivers, and one of the Focal TC120 tweeters. I fully expected that I could run the tweeter full range and would have a total system efficiency of around 91-92db's at most, probably less when you take into account the losses due to inductors. However, what I end up with is a 97db efficiency from the midrange drivers. It's higher than the tweeter, of course, and higher than the midbass drivers, though even those were higher than expected. Does Speaker workshop work off voltage sensitivity when calculating efficiency? If so that would better explain the difference I see vs what I predicted.
Here is the design concept I have been playing with recently. After reading a few diy designs that used this TB full range as a midrange, and seeing some test measurements, I started thinking more about using it. It's pretty cheap, so I feel like I can't go wrong. This design is a very rough design mockup that doesn't even fully work, but it was more to see how a 3 way of this sort would work. It uses two TB 4" ti drivers as midranges, two Peerless 8" HDS nomex cone midbass drivers for the bass, and a Focal Tc120Tdx for the tweeter. The problem I ran into, as I mentioned earlier, is that the response ended up being more efficient than I expected. If this really is how efficient its going to be, I think I need to play around with some other more efficient tweeters. I suppose I could add a super tweeter above 10k. I could also have a system whose response is down 5db's at 10K on up, and just not worry about it. Anyway, from a design concept, I'd appreciate comments.
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