>>> However I do wonder if I can achieve something more with (imho) these wonderfull bamboo drivers by matching them in a suitable enclosure and a suitable sub.
I have those Bamboo's and really like them too! I use them without sub and they fill my small room with HT sound. They are really great for music and efficient enough to use with a cheap T-amp. A few friends prefer the Bamboo's to any of the Fostex speakers i've had in my office... large and small. Tweeter is optional with Bamboo but i prefer with. One day i will bring them downstairs and sit them on top of my 15" H-frames. I have no doubt they will perform beautifully!
http://www.zillaaudio.com/tb-1320-bamboo.htm
Looking at the box designed years ago i may have done something differently with them now. I'm sure there are better boxes than mine but mine suffice for their current application.
>>> One item coming to mind is a woofer in a H-frame (prefer to keep it relative small, can I get away with a 12"?).
I think a 12" H-frame will sound very good. One thing i learned from MJK's 15 and 18" H-frames is that you do not need an expensive driver, rather one with suitable specs. Tho not perfect, i wonder how the Alpha 12 would sound and noticed an inexpensive Jamo that looks like it might work too. If you are powering these with a sub amp i see no reason they can't be used. My only concern is how deep the bass will go and if sealed or powered subs are better sonically compared to 12" H-frames. The 15" have lots of grunt and power and produce tuneful, detailed bass that's never bloated (on OB alone, the Alpha 15's had a bit of bloat that's gone when in H-frames... in my room anyway). I'd consider one of these drivers. If i have time later i will plug the numbers in and produce a chart. But i think H-frames really provide audiophile quality bass. They are an interesting alternative to powered hi excursion subwoofers in boxes.
Eminence Alpha-12A 12" Guitar/PA Driver | Parts-Express.com
JAMO 20325 12" Paper Cone Woofer 4 Ohm | Parts-Express.com
I have those Bamboo's and really like them too! I use them without sub and they fill my small room with HT sound. They are really great for music and efficient enough to use with a cheap T-amp. A few friends prefer the Bamboo's to any of the Fostex speakers i've had in my office... large and small. Tweeter is optional with Bamboo but i prefer with. One day i will bring them downstairs and sit them on top of my 15" H-frames. I have no doubt they will perform beautifully!
http://www.zillaaudio.com/tb-1320-bamboo.htm
Looking at the box designed years ago i may have done something differently with them now. I'm sure there are better boxes than mine but mine suffice for their current application.
>>> One item coming to mind is a woofer in a H-frame (prefer to keep it relative small, can I get away with a 12"?).
I think a 12" H-frame will sound very good. One thing i learned from MJK's 15 and 18" H-frames is that you do not need an expensive driver, rather one with suitable specs. Tho not perfect, i wonder how the Alpha 12 would sound and noticed an inexpensive Jamo that looks like it might work too. If you are powering these with a sub amp i see no reason they can't be used. My only concern is how deep the bass will go and if sealed or powered subs are better sonically compared to 12" H-frames. The 15" have lots of grunt and power and produce tuneful, detailed bass that's never bloated (on OB alone, the Alpha 15's had a bit of bloat that's gone when in H-frames... in my room anyway). I'd consider one of these drivers. If i have time later i will plug the numbers in and produce a chart. But i think H-frames really provide audiophile quality bass. They are an interesting alternative to powered hi excursion subwoofers in boxes.
Eminence Alpha-12A 12" Guitar/PA Driver | Parts-Express.com
JAMO 20325 12" Paper Cone Woofer 4 Ohm | Parts-Express.com
I see that at one stage you had the Fostex BK101 which (hybrid?) hron fits a number of different drivers. Did you ever give thought to putting the Tang Band W4-1320SJ in one of those?
AM
I cut up wood to make a BIB for the Bamboos but all of the pine planks remain leaning against the basement wall. Maybe one day i will put it together. I never heard it in anything but the ported box i made for it.
The bk101 is still playing at uncle eli's. He told me a painter did some work at his house and he left the stereo on for him. The guy told him the speakers sounded great. They have the radio shack 1197 in them. I think i paid $1 for each driver when they were being discontinued.
For some reason, the way i feel is that the TBs are better suited for ported and sealed boxes while the more efficient Fostex type drivers work better in back horns of some kind to bump up and balance out the bass response.
PS. LOL AM, i just looked at another thread and saw your attachment of the bk101 i used.
The bk101 is still playing at uncle eli's. He told me a painter did some work at his house and he left the stereo on for him. The guy told him the speakers sounded great. They have the radio shack 1197 in them. I think i paid $1 for each driver when they were being discontinued.
For some reason, the way i feel is that the TBs are better suited for ported and sealed boxes while the more efficient Fostex type drivers work better in back horns of some kind to bump up and balance out the bass response.
PS. LOL AM, i just looked at another thread and saw your attachment of the bk101 i used.
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Here's a sim on open baffle. I don't have much experience interpreting sims on ob but did this to see how the curves looked to compare. If we can assume the Alpha 15 is a 'good choice' in an H-frame based on the curves i would estimate both Jamo's follow it's curve whereas the Alpha 12 does not, especially in the deepest bass that it can reproduce. This is just a guess as to whether the Jamo's or the Alpha 12 might work well in H-frames.
Based on what i see, either Jamo would work if using a dedicated amp to power them. This way their lower sensitivity would not be an issue. The Alpha 12 does not look like a good choice to me because its response continues to dip.
This chart must look funny but understanding that the H-frame response will be cut out around 200hz and equalization circuits are applied (my amp has a variable crossover which i think is set to around 60hz) the response balances out from around 30hz thru 200hz.
Maybe someone could shed more light on this?
Zilla
Based on what i see, either Jamo would work if using a dedicated amp to power them. This way their lower sensitivity would not be an issue. The Alpha 12 does not look like a good choice to me because its response continues to dip.
This chart must look funny but understanding that the H-frame response will be cut out around 200hz and equalization circuits are applied (my amp has a variable crossover which i think is set to around 60hz) the response balances out from around 30hz thru 200hz.
Maybe someone could shed more light on this?
Zilla
Attachments
Godzilla, those Jamo woofers are super affordable, so why not use 2 of them per side? IMO maybe even a 4 woofer H-frame tower per side? 🙂
Zaph|Audio
different size, nevertheless, if John Krutke likes it, you may too.
P.E. sells it. I thinks it's $11
different size, nevertheless, if John Krutke likes it, you may too.
P.E. sells it. I thinks it's $11
Zilla
I do not know if you have seen this very interesting thread which is using a rather elegant and reasonable priced solution in which the w4-1320sj is used as a mid without any baffle.....
http://www.diyaudio.com/forums/multi-way/161768-violet-dsp-evolution-open-baffle-project.html
regards, AM
>>> Godzilla, those Jamo woofers are super affordable, so why not use 2 of them per side? IMO maybe even a 4 woofer H-frame tower per side? 🙂
Don't buy them all up... i may grab a few this week. I was thinking of making 4 smaller H-frames and stacking them... two per side. But four per side should be really great and just stand something beside them for an amazing system! Maybe a small stand mount? I don't need them but for $10 i might not mind them sitting in storage (with their larger 15" brothers also sitting in storage lol)... I really need to clean up my inventory of drivers!
Thanks AM, i will read thru that thread. I did not see it but would like to know how it turned out. Funny to me how we buy these 'full range' drivers then add expensive tweeters and woofer systems to them.
Zilla
Don't buy them all up... i may grab a few this week. I was thinking of making 4 smaller H-frames and stacking them... two per side. But four per side should be really great and just stand something beside them for an amazing system! Maybe a small stand mount? I don't need them but for $10 i might not mind them sitting in storage (with their larger 15" brothers also sitting in storage lol)... I really need to clean up my inventory of drivers!
Thanks AM, i will read thru that thread. I did not see it but would like to know how it turned out. Funny to me how we buy these 'full range' drivers then add expensive tweeters and woofer systems to them.
Zilla
It's kind of funny that I'm actually quite pleased with the performance of the Aurasound Ns3-193-8A in a 1.5L loosely built cardboard box! With a 6dB bass boost I thought I was having a subwoofer! Of course this happens in a tiny room, maybe bedroom, only, but the effect's quite fascinating.
In fact, is anyone trying absorbing foam baffle? I think it's gonna be quite interesting. Felt ring around tweeter's been around for decades, I think it's LS3/5A, and what if felt ring/foam rings around all the drivers?
Morgan Jones has written an article on the Arpeggio loudspeaker and is using a felt baffle. Look up the thread and article on this forum.
Cheers
I've lived with my 9 NS3 knockoff towers for several weeks now, and feel satisfied enough with their performance to go ahead and build 8 more of them using the PVC pipe.
I suspect one reason that they sound as satisfactory as they do considering floor bounce and the driver size is due to their arrangement and enclosure. It seems likely that the ~30" vertical distribution of the drivers smooths out floor and ceiling bounce response anomalies enough that they don't seriously detract from the overall apparent response at the listening seat (~12 feet away).
With 9 of these drivers per speaker, the total cone area (and excursion) are comparable to that of a 10" woofer which should allow reasonable SPL. Plus, with a ~350uF series input capacitor, simulation shows that the driver's Xmax won't be exceeded except above 100Wrms in at about 50-60hz. I should mention that I also 'treate' the spider for these speakers to achieve free air resonance in the 60hz range - not too shabby for a 3.5" driver. In my final version, I plan to use activated carbon in the enclosure for 'compliance enhancement' which should increase the apparent enclosure volume by up to double which should also materially help the LF response and allow xover to the SW around 50hz.
My xover includes 4.5db of BSC correction by running the outer six drivers only below about 3khz (the approx baffle step transition frequency of the 3.75" wide 'flat' that the speakers are mounted on). Then between 3-6 khz, only the center three speakers are active. Finally, I have arranged a HF circuit to give up to 10db boost to just the center speaker of the 9 to maintain the overall response out to above 15khz at the reference efficiency of 86-87 db/w/m. This seems to keep the important advantages of a full range driver that everything seems to come from a single acoustical center, but dispersion is significantly better than a single driver with equivalent cone area, and with all 9 drivers being the same having a symmetrical arrangement, there is no sense of discontinuity over a xover region.
Finally, being floor standing speakers yet occupying less than an 8" x 8" area and having the drivers all more than 2' from the floor, they can be placed almost anywhere in a room where there is a little space.
I suspect one reason that they sound as satisfactory as they do considering floor bounce and the driver size is due to their arrangement and enclosure. It seems likely that the ~30" vertical distribution of the drivers smooths out floor and ceiling bounce response anomalies enough that they don't seriously detract from the overall apparent response at the listening seat (~12 feet away).
With 9 of these drivers per speaker, the total cone area (and excursion) are comparable to that of a 10" woofer which should allow reasonable SPL. Plus, with a ~350uF series input capacitor, simulation shows that the driver's Xmax won't be exceeded except above 100Wrms in at about 50-60hz. I should mention that I also 'treate' the spider for these speakers to achieve free air resonance in the 60hz range - not too shabby for a 3.5" driver. In my final version, I plan to use activated carbon in the enclosure for 'compliance enhancement' which should increase the apparent enclosure volume by up to double which should also materially help the LF response and allow xover to the SW around 50hz.
My xover includes 4.5db of BSC correction by running the outer six drivers only below about 3khz (the approx baffle step transition frequency of the 3.75" wide 'flat' that the speakers are mounted on). Then between 3-6 khz, only the center three speakers are active. Finally, I have arranged a HF circuit to give up to 10db boost to just the center speaker of the 9 to maintain the overall response out to above 15khz at the reference efficiency of 86-87 db/w/m. This seems to keep the important advantages of a full range driver that everything seems to come from a single acoustical center, but dispersion is significantly better than a single driver with equivalent cone area, and with all 9 drivers being the same having a symmetrical arrangement, there is no sense of discontinuity over a xover region.
Finally, being floor standing speakers yet occupying less than an 8" x 8" area and having the drivers all more than 2' from the floor, they can be placed almost anywhere in a room where there is a little space.
I calculated how far a response null due to floor bounce would be spread with a vertical array of speakers from 25" to 57" from the floor at a listening distance of 12 feet with the listener's ear ~42" from the floor. The spread in null frequencies was a little more than an octave (from about 170-400hz) which should be enough to change it to a broad dip of a db or two rather than a sharp near total cancellation at a single frequency. I suspect that in the case of this particular speaker, having a little reduction in this region may actually contribute to the overall impression of midbass flatness and bass extension.
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