Hi Dan,
It is nice to see you out here soliciting ideas from your potential customers, the DIY community.
I would like to add my 2 cents to the list of driver request.
My request mirrors a few that you already have. But, I would like to add a 16 ohm impedance driver.
An 8 inch 16 ohm wideband driver that is 97 db efficient that could be used in unison with a quality ribbon tweeter like the Fountek neo 5.0 on an OB in a MTM configuration. An 8 inch driver that could work down to a -3db at 100Hz and up to 10kHz on a narrow OB. I think the vintage Stephens Tru-Sonic 80FR is a good comparison driver.
An MTM speaker configuration that would yeild close to 100db and not need a crossover on the wideband driver to cloud the critical mid-band.
Of course the OB baffle would need to be less than 24" on the front section for WAF. But, wings would be needed, extending the baffle width to realistically support the desired 100Hz to 10kHz frequency response.
This hypothetical speaker driver and configuration could allow the flea powered tube amplifiers of 2 watts or less to apply.
And a good sub-bass woofer with plenty of excersion capabilities that will yeild 30Hz to 250Hz -3db on an OB would be nice too.
The sound quality from a OB compared to a box speaker is like night and day IMHO, no box colorations allowed.
Thanks
Norris Wilson
It is nice to see you out here soliciting ideas from your potential customers, the DIY community.
I would like to add my 2 cents to the list of driver request.
My request mirrors a few that you already have. But, I would like to add a 16 ohm impedance driver.
An 8 inch 16 ohm wideband driver that is 97 db efficient that could be used in unison with a quality ribbon tweeter like the Fountek neo 5.0 on an OB in a MTM configuration. An 8 inch driver that could work down to a -3db at 100Hz and up to 10kHz on a narrow OB. I think the vintage Stephens Tru-Sonic 80FR is a good comparison driver.
An MTM speaker configuration that would yeild close to 100db and not need a crossover on the wideband driver to cloud the critical mid-band.
Of course the OB baffle would need to be less than 24" on the front section for WAF. But, wings would be needed, extending the baffle width to realistically support the desired 100Hz to 10kHz frequency response.
This hypothetical speaker driver and configuration could allow the flea powered tube amplifiers of 2 watts or less to apply.
And a good sub-bass woofer with plenty of excersion capabilities that will yeild 30Hz to 250Hz -3db on an OB would be nice too.
The sound quality from a OB compared to a box speaker is like night and day IMHO, no box colorations allowed.
Thanks
Norris Wilson
>>> To do full range, we'd need to look at lowering the efficiency into the 90 dB range. That would allow extension to the 40-45 Hz range. A lot better for most music!
I could live with that as an alternative to some of the Fostex gear.
I’m intrigued by the Hemp… and want to buy the Hemp… based on feedback it seems they sound really good. We all love that crossoverless midrange but Fostex, Lowther, etc have their characteristic forward sound. This is where you can capitalize on their shortcoming. Please design and build an efficient enough full or wide range driver to be used with SE or the great little SI digital amp (and similar upcoming amps using this technology) so I can get my full range fix!
If you can make it 91 – 94db eff… more laid back/less forward sounding than the Fostex/Lowther… and place the Qts in the .3 to .4 range I think several interesting cabinets will crop up.
I would replace my fantastic value Pioneer B20 with a Hemp driver if it will work in a similarly sized cabinet. Would love to have better sound in a cabinet anywhere from .25 to 1.75 cubic feet. Whatever you build it will be interesting how you blend the two technologies.
Peace,
Godzilla
I could live with that as an alternative to some of the Fostex gear.
I’m intrigued by the Hemp… and want to buy the Hemp… based on feedback it seems they sound really good. We all love that crossoverless midrange but Fostex, Lowther, etc have their characteristic forward sound. This is where you can capitalize on their shortcoming. Please design and build an efficient enough full or wide range driver to be used with SE or the great little SI digital amp (and similar upcoming amps using this technology) so I can get my full range fix!
If you can make it 91 – 94db eff… more laid back/less forward sounding than the Fostex/Lowther… and place the Qts in the .3 to .4 range I think several interesting cabinets will crop up.
I would replace my fantastic value Pioneer B20 with a Hemp driver if it will work in a similarly sized cabinet. Would love to have better sound in a cabinet anywhere from .25 to 1.75 cubic feet. Whatever you build it will be interesting how you blend the two technologies.
Peace,
Godzilla
What I'm looking for, not that I imagine it's worth much as I'm looking for something, shall we say, specialized, is ...
- mid 90's eff.
- less than 6" diameter
- suitable to cover 150 hz and up in an OB
Alternatively, I'd consider a small diameter (say, 8") coaxial.
I'm attempting to design a high eff. OB with simple crossover requirements and minimized beaming. I will cross over to a tweeter, but I'd like to do so as high a frequency as I can without objectional (to me) beaming.
At this moment, two pairs of FE126Es or FE127Es in MTM configuration seem like the best candidates. But, I am concerned about the limited xmax for those. BTW, does anyone know if the xmax for the FE127E is 0.35 or 0.67?
Perhaps I should have picked up two pairs of FE108EZs when they were going cheap...
If Hemp Acoustics came out with something suitable (and I could afford them), I'd buy a pair.
Paul Ebert
- mid 90's eff.
- less than 6" diameter
- suitable to cover 150 hz and up in an OB
Alternatively, I'd consider a small diameter (say, 8") coaxial.
I'm attempting to design a high eff. OB with simple crossover requirements and minimized beaming. I will cross over to a tweeter, but I'd like to do so as high a frequency as I can without objectional (to me) beaming.
At this moment, two pairs of FE126Es or FE127Es in MTM configuration seem like the best candidates. But, I am concerned about the limited xmax for those. BTW, does anyone know if the xmax for the FE127E is 0.35 or 0.67?
Perhaps I should have picked up two pairs of FE108EZs when they were going cheap...
If Hemp Acoustics came out with something suitable (and I could afford them), I'd buy a pair.
Paul Ebert
Thanks all! To just start summarizing, it looks like a 6" driver would be preferred to an 8" (some have asked for 4s, some for 8s, some for 6s, so perhaps the middle size - 6 - is where to start?). And for most, you want the efficiency in the 95 dB range - mid 90s.
Boxes seems to be universally sealed and big; there's no fear of a 3-4 cubic foot box, which is what's required to get a 6" woofer with 94-95 dB efficiency and an F3 in the 70-80 Hz range.
Open baffles are also requested, so we should use a small motor structure (neo based), and a very open basket. I don't think I can get the flux with ceramic, and AlNiCo just isn't as good as neo (contrary to what some pine for from the past, AlNiCo really isn't a good magnetic material - it's not as strong as neo, doesn't hold up as strongly in a magnetic field as neo, and is more expensive).
Of course, the OB guys will have to use some EQ/crossovers to burn efficiency if they want to keep the extension down to the 100 Hz range; for a 24" wide baffle, you'll have to look at burning 8-10 dB SPL to get it flat down to 100 Hz or so.
Does it look like I'm summarizing things properly?
One other thing - video shielded, I assume?
Dan Wiggins
Adire Audio®
Boxes seems to be universally sealed and big; there's no fear of a 3-4 cubic foot box, which is what's required to get a 6" woofer with 94-95 dB efficiency and an F3 in the 70-80 Hz range.
Open baffles are also requested, so we should use a small motor structure (neo based), and a very open basket. I don't think I can get the flux with ceramic, and AlNiCo just isn't as good as neo (contrary to what some pine for from the past, AlNiCo really isn't a good magnetic material - it's not as strong as neo, doesn't hold up as strongly in a magnetic field as neo, and is more expensive).
Of course, the OB guys will have to use some EQ/crossovers to burn efficiency if they want to keep the extension down to the 100 Hz range; for a 24" wide baffle, you'll have to look at burning 8-10 dB SPL to get it flat down to 100 Hz or so.
Does it look like I'm summarizing things properly?
One other thing - video shielded, I assume?
Dan Wiggins
Adire Audio®
I think a 6" sounds great, especially one that might work will in a BassZilla type OB (like Paul Ebert was hinting at, right?).
I'd like to see something very similar to the current 8", but with greater excursion. It appears to me that if the 8.0DIY had >5mm of excursion, it would be difficult to exceed Xmax in a 40L sealed enclosure.
I would also like to see either an 8" or a 6" that worked well in some sort of transmission line. I'd like to build a Hemp BIB, but the diminsions the current 8" needs are out of the question for me. I also really like the proportions of MLTL's. If a hemp were optimized for one or both, I'd be thrilled. Either way, it seems that lower compliance is needed here.
Video sheilding would be nice, but it isn't esential. I don't like enclosures over 2 or so cu. ft. unless they are tall and skinny (a TL variation). I'd rather have a large sub that can sit out of the way and can really handle the bottom octave. A 6" driver in a 4 cu. ft. box that really needs a sub is not my cup of tea. A whizzer-less driver would be great, as long as the hf dispersion doesn't get narrower or distortion higher. Finally, a Hemp Coax would be really cool as well.
Paul
I'd like to see something very similar to the current 8", but with greater excursion. It appears to me that if the 8.0DIY had >5mm of excursion, it would be difficult to exceed Xmax in a 40L sealed enclosure.
I would also like to see either an 8" or a 6" that worked well in some sort of transmission line. I'd like to build a Hemp BIB, but the diminsions the current 8" needs are out of the question for me. I also really like the proportions of MLTL's. If a hemp were optimized for one or both, I'd be thrilled. Either way, it seems that lower compliance is needed here.
Video sheilding would be nice, but it isn't esential. I don't like enclosures over 2 or so cu. ft. unless they are tall and skinny (a TL variation). I'd rather have a large sub that can sit out of the way and can really handle the bottom octave. A 6" driver in a 4 cu. ft. box that really needs a sub is not my cup of tea. A whizzer-less driver would be great, as long as the hf dispersion doesn't get narrower or distortion higher. Finally, a Hemp Coax would be really cool as well.
Paul
thanks for your attention, Dan.
To distill abit, early on, it looks like 6 inch, non-whiz, with a mid Q .4-ish, and higher Q OB-able .8-.9 driver would I think be gangbusters. I also agree with Paul about the idea of an FR 8 with some healthy Xmax. 40L sealed. MMMMmmm
The Cult of the Openly Baffled is enjoying a rapidly growing congregation. Most people are hooked just by listening to a well implemented system. What it needs is one GREAT alternative choice, where there are soooooo few, really.
Based on my fantastically positive experience with the tonality of the OEM Hemp 8 of Omega SuperHemp, the idea of a non wiz, high Q, 6 inch for open baffle, is to me, almost too good to be true. A unique offering.
No. 1 Choice: 6 inch, mid and high Q, non whiz. Good SPL.
To distill abit, early on, it looks like 6 inch, non-whiz, with a mid Q .4-ish, and higher Q OB-able .8-.9 driver would I think be gangbusters. I also agree with Paul about the idea of an FR 8 with some healthy Xmax. 40L sealed. MMMMmmm
The Cult of the Openly Baffled is enjoying a rapidly growing congregation. Most people are hooked just by listening to a well implemented system. What it needs is one GREAT alternative choice, where there are soooooo few, really.
Based on my fantastically positive experience with the tonality of the OEM Hemp 8 of Omega SuperHemp, the idea of a non wiz, high Q, 6 inch for open baffle, is to me, almost too good to be true. A unique offering.
No. 1 Choice: 6 inch, mid and high Q, non whiz. Good SPL.
Definitely need more drivers that will work well on OB. Personally, if you're trying to go full range with a driver, I don't mind them large, I don't mind whizzers, and I like phase plugs.
Maybe something like the big 10"ers Zu uses (which I think are just phase plug modified versions of this: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=290-495 ). They have too low Qts to be useful on OB, but maybe with the smaller, neo motor structure and a more optimized basket . . .
I think I'm mainly looking for something that'll go 40-16000 on OB, maybe like 92dB efficiency (I'm not as greedy, though I like to power things with a T-Amp when I can). I can cope with a supertweeter (might not actually be necessary because all I can really hear when playing freqs beyond 16khz seem to be lower harmonics), and though I can localize bass below 80hz, I can't below 40hz, so I can just build some form of sub for that if it becomes necessary.
Totally looking forward to what comes out.
Kensai
Maybe something like the big 10"ers Zu uses (which I think are just phase plug modified versions of this: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=290-495 ). They have too low Qts to be useful on OB, but maybe with the smaller, neo motor structure and a more optimized basket . . .
I think I'm mainly looking for something that'll go 40-16000 on OB, maybe like 92dB efficiency (I'm not as greedy, though I like to power things with a T-Amp when I can). I can cope with a supertweeter (might not actually be necessary because all I can really hear when playing freqs beyond 16khz seem to be lower harmonics), and though I can localize bass below 80hz, I can't below 40hz, so I can just build some form of sub for that if it becomes necessary.
Totally looking forward to what comes out.
Kensai
Kensai,
Have you considered the Hawthorne Silver Iris? It sounds like it would be perfect for you. My only concerns with mine are beaming and some muddiness in the midrange (which may very well be my implementation). No phase plug, of course (being coaxial).
I believe you are correct about the Zu driver. It was the Druids that got me going in the high efficiency direction. Nice speaker.
Paul Ebert
Have you considered the Hawthorne Silver Iris? It sounds like it would be perfect for you. My only concerns with mine are beaming and some muddiness in the midrange (which may very well be my implementation). No phase plug, of course (being coaxial).
I believe you are correct about the Zu driver. It was the Druids that got me going in the high efficiency direction. Nice speaker.
Paul Ebert
DanWiggins said:
Yes, an open basket and narrow motor would be very nice. Though I wonder how vital that would be above 100 hz.
Can you elaborate, for the benefit of this newbie, why I should expect to burn 8 to 10 db? Is it lost in the crossover itself or is it just the baffle cancellation? One thing I've considered is to have the baffle cancellation be the high-pass for the 'full-range' driver. Is that even conceivable? I suppose I might need to deal with bottoming out the driver. Thoughts?
Thanks!
Paul Ebert
Paul,
It is from the baffle cancellation. If you have a 24" wide baffle, and you're centered on the baffle, you have a 24" path length from the center of the front to the center of the rear. This means at frequencies equal to or LONGER than 24", it will start cancelling. And that is ~500 Hz.
Now, you roll off at 6 dB per octave below your cancellation point, as a good "rule of thumb". So from 500 Hz to 250 Hz, you lose 6 dB. From 250 Hz to 125 Hz, you lose another 6 dB. So theoretically you lose 12-13 dB at 100 Hz from your dipole. In reality, it will be closer to 8-10 dB, because there isn't an instantaneous roll-off to the response.
So, assuming your woofer is 95 dB efficient at 500+ Hz, in a 24" wide panel it will have 85 dB output down around 100 Hz. To get the response back to flat - relative to the 100 Hz level - you need to cut the overall efficiency of the driver down to 85 dB. So now you need a 100W amp to get where a 10W amp would do if the driver was really 95 dB over the full range.
Someone will invariably shout "use EQ to pump up the bass!" I would point out that such a requirement would result in the same thing; you need that 10W, but then add 10dB of gain to the lower end, meaning you need 100W down low.
Whatever way you slice it, bandwidth and open baffles do not give you high efficiency. For midranges, sure an open baffle makes sense if you want to keep efficiency; for lower frequencies, the required panel width gets big REALLY fast, and that forces you to either burn efficiency, or crank up the gain. Either way, you end up needing a lot of power. You have to "give the devil his due" in either case...
Dan Wiggins
Adire Audio®
It is from the baffle cancellation. If you have a 24" wide baffle, and you're centered on the baffle, you have a 24" path length from the center of the front to the center of the rear. This means at frequencies equal to or LONGER than 24", it will start cancelling. And that is ~500 Hz.
Now, you roll off at 6 dB per octave below your cancellation point, as a good "rule of thumb". So from 500 Hz to 250 Hz, you lose 6 dB. From 250 Hz to 125 Hz, you lose another 6 dB. So theoretically you lose 12-13 dB at 100 Hz from your dipole. In reality, it will be closer to 8-10 dB, because there isn't an instantaneous roll-off to the response.
So, assuming your woofer is 95 dB efficient at 500+ Hz, in a 24" wide panel it will have 85 dB output down around 100 Hz. To get the response back to flat - relative to the 100 Hz level - you need to cut the overall efficiency of the driver down to 85 dB. So now you need a 100W amp to get where a 10W amp would do if the driver was really 95 dB over the full range.
Someone will invariably shout "use EQ to pump up the bass!" I would point out that such a requirement would result in the same thing; you need that 10W, but then add 10dB of gain to the lower end, meaning you need 100W down low.
Whatever way you slice it, bandwidth and open baffles do not give you high efficiency. For midranges, sure an open baffle makes sense if you want to keep efficiency; for lower frequencies, the required panel width gets big REALLY fast, and that forces you to either burn efficiency, or crank up the gain. Either way, you end up needing a lot of power. You have to "give the devil his due" in either case...
Dan Wiggins
Adire Audio®
Kensai,
Unfortunately, high efficiency and high Q are quite incompatible; it's the way drivers are built that force this relationship.
For a high Q design, we need to have a relatively weak motor; the weaker the motor (the lower the BL) for a given mass, we will raise the Q of the speaker (I'm assuming we don't want to raise the Q via a stiff suspension, since that will raise the Fs of the driver).
Now, how do we get efficiency out of a speaker? Low moving mass and high BL. That's it. Cut the Mms, or raise the BL, and you'll increase efficiency.
Combine those two paragraphs; to do a high Q design, we know we need a low BL. And to get high efficiency, we know we must lower the Mms (since we have to keep the BL low for the higher Q).
However, there's a limit in how low we can go in Mms! A low Mms for a 6.5" woofer would be 8 grams; that would be REALLY light! That's kind of the bottom for what you can realistically get with a 6.5" driver.
Now that we've pegged the Mms as low as we can, we know we can raise the BL as little as possible to get us the required efficiency. Problem is, to get back to the 95-96 dB SPL range, we'll need to raise the BL into the 9 N/A range. This would give us the required efficiency; however, it will also give us a Q around 0.25...
There is always stiffening the suspension; that will raise the Qts quite a bit! However, it will also raise the Fs, prohibitively so. Cranking the Q up via stiffer suspension would push your Fs into the 100+ Hz range, meaning bye bye lower extension...
So, in essence, looking for a high efficiency, high Q driver is kind of like looking for a 12 passenger van that out-hustles a Carrera 4 around the track. You can get one or the other, but not both.
This should also indicate why the average high efficiency driver is always low Q; you simply can't run the Mms down to where you'd need it to be to get the solution, unless we can come up with negative-mass materials.
Dan Wiggins
Adire Audio®
Unfortunately, high efficiency and high Q are quite incompatible; it's the way drivers are built that force this relationship.
For a high Q design, we need to have a relatively weak motor; the weaker the motor (the lower the BL) for a given mass, we will raise the Q of the speaker (I'm assuming we don't want to raise the Q via a stiff suspension, since that will raise the Fs of the driver).
Now, how do we get efficiency out of a speaker? Low moving mass and high BL. That's it. Cut the Mms, or raise the BL, and you'll increase efficiency.
Combine those two paragraphs; to do a high Q design, we know we need a low BL. And to get high efficiency, we know we must lower the Mms (since we have to keep the BL low for the higher Q).
However, there's a limit in how low we can go in Mms! A low Mms for a 6.5" woofer would be 8 grams; that would be REALLY light! That's kind of the bottom for what you can realistically get with a 6.5" driver.
Now that we've pegged the Mms as low as we can, we know we can raise the BL as little as possible to get us the required efficiency. Problem is, to get back to the 95-96 dB SPL range, we'll need to raise the BL into the 9 N/A range. This would give us the required efficiency; however, it will also give us a Q around 0.25...
There is always stiffening the suspension; that will raise the Qts quite a bit! However, it will also raise the Fs, prohibitively so. Cranking the Q up via stiffer suspension would push your Fs into the 100+ Hz range, meaning bye bye lower extension...
So, in essence, looking for a high efficiency, high Q driver is kind of like looking for a 12 passenger van that out-hustles a Carrera 4 around the track. You can get one or the other, but not both.
This should also indicate why the average high efficiency driver is always low Q; you simply can't run the Mms down to where you'd need it to be to get the solution, unless we can come up with negative-mass materials.
Dan Wiggins
Adire Audio®
Hi Dan,
In reference to the open baffle width of 24" and the loss of frequency extention and efficiency.
Could this loss and extention be corrected somewhat by increasing the baffle width in the form of wings? A width of 38" could easy be obtainable.
When using my hypothetical MTM example given above as the criteria of a desired 16 ohm 8" wideband driver for OB use.
Wouldn't the doubling up of these drivers help with this loss of efficiency and frequency extention as well?
Also, would the slight combing effect of the MTM configuration help in reducing high frequency beaming?
Or, is the designing of a 16 ohm wideband driver taylored for OB use, impractical for commercial considerations?
Norris Wilson
In reference to the open baffle width of 24" and the loss of frequency extention and efficiency.
Could this loss and extention be corrected somewhat by increasing the baffle width in the form of wings? A width of 38" could easy be obtainable.
When using my hypothetical MTM example given above as the criteria of a desired 16 ohm 8" wideband driver for OB use.
Wouldn't the doubling up of these drivers help with this loss of efficiency and frequency extention as well?
Also, would the slight combing effect of the MTM configuration help in reducing high frequency beaming?
Or, is the designing of a 16 ohm wideband driver taylored for OB use, impractical for commercial considerations?
Norris Wilson
Norris,
Wider helps, but to keep all the efficiency you need to go REALLY wide; 38" wide would give you ~350 Hz for a cutoff point, so you'll be ~6 dB down at 175 Hz, and realistically 6-8 dB down at 100 Hz.
I know you want to do an OB, but trying to do a high efficiency OB is really chasing your tail; the things required to keep the efficiency up in the lower frequencies drive you more and more to an infinite baffle, or psuedo-huge-closed-box type design, no longer a dipole OB. Or you burn efficiency and accept the EQ required to get response to the lower midrange.
Perhaps an OB for the midrange above 500 Hz, and conventional sealed boxes for below that point?
Dan Wiggins
Adire Audio®
Wider helps, but to keep all the efficiency you need to go REALLY wide; 38" wide would give you ~350 Hz for a cutoff point, so you'll be ~6 dB down at 175 Hz, and realistically 6-8 dB down at 100 Hz.
I know you want to do an OB, but trying to do a high efficiency OB is really chasing your tail; the things required to keep the efficiency up in the lower frequencies drive you more and more to an infinite baffle, or psuedo-huge-closed-box type design, no longer a dipole OB. Or you burn efficiency and accept the EQ required to get response to the lower midrange.
Perhaps an OB for the midrange above 500 Hz, and conventional sealed boxes for below that point?
Dan Wiggins
Adire Audio®
Dan,
Thanks for giving us diyers the opportunity to voice our wants.
High efficient speaker is one where the efficiency region is usable/sounds good. I don't consider a 98db 8" high efficiency where the "efficiency" is created by a whizzer and sputters, spits and quacks from/between 1kHz to 10kHz.
An 8" full range is a bad compromise of high end extension and bass. An 8" simply cannot perform well beyond 2kHz. And there is nothing you can do about it short of adding a tweeter or perhaps some type of complicated phase plug horn load contraption. And on top if this it still may need a $$$ super tweeter(!).
6" drivers are somewhat better sounding a tad quicker in mids, but suffers the same high end shortcoming of the 8".
4"-4.5" offers the best compromise of treble and bass of all wide range drivers. Some of the better drivers can make it to 10kHz and beyond and sound good. The weakness is the bass, however there is something that can done about it. Sub or big horn cab (like BIB). Somehow "adding" bass to a 4" is better than adding a whizzer to an 8".
And it is no wonder that one of the best wider range drivers is the JX92s.
I would simply say to make something similar, but use Hemp and your XBL motor techonology. Make high and low QTS versions with the corresponding rise in the treble for the latter. It is up to the diyer to select the proper driver and cab for their particular bass requirements.
Thanks for giving us diyers the opportunity to voice our wants.
High efficient speaker is one where the efficiency region is usable/sounds good. I don't consider a 98db 8" high efficiency where the "efficiency" is created by a whizzer and sputters, spits and quacks from/between 1kHz to 10kHz.
An 8" full range is a bad compromise of high end extension and bass. An 8" simply cannot perform well beyond 2kHz. And there is nothing you can do about it short of adding a tweeter or perhaps some type of complicated phase plug horn load contraption. And on top if this it still may need a $$$ super tweeter(!).
6" drivers are somewhat better sounding a tad quicker in mids, but suffers the same high end shortcoming of the 8".
4"-4.5" offers the best compromise of treble and bass of all wide range drivers. Some of the better drivers can make it to 10kHz and beyond and sound good. The weakness is the bass, however there is something that can done about it. Sub or big horn cab (like BIB). Somehow "adding" bass to a 4" is better than adding a whizzer to an 8".
And it is no wonder that one of the best wider range drivers is the JX92s.
I would simply say to make something similar, but use Hemp and your XBL motor techonology. Make high and low QTS versions with the corresponding rise in the treble for the latter. It is up to the diyer to select the proper driver and cab for their particular bass requirements.
I hate to contradict someone who knows so much more than I, but the OB's below are 96db/1w/1m in a small size, except the one on the left which uses a Fostex 108ESigma (so I had to pad the Iris woofer down). The pair in the center are Visiton B200's and the 15's are both the Silver Iris's. The larger U-baffles are 16" deep and you'd need a comparable flat baffle over 60" wide in terms of bass extension. The B200 baffles are 13" deep and are the equivalent of over a 50" wide flat baffle. The bases of each are Helmholtz loaded RLH's to increase extension making the B200's have a -3db of about 40hz and the big ones don't drop off until 27hz. None use any filter or EQ, except the 2 way with the 108, which has only an inductor on the woofer, and the Iris which has a built in XO since it's a coax.
The bottom line is that highish Q and efficiency are not mutually exclusive, and neither is OB with bass, without EQ, in a domestically acceptable size.
I'd like to see a high efficiency, high Q, 12" coax with a good quality dome tweet that can keep up mounted in the middle instead of the pro compression tweeters that have to be padded down, to obtain the same point source sound as a true full ranger, but can make real bass in OB without needing a sub.
The bottom line is that highish Q and efficiency are not mutually exclusive, and neither is OB with bass, without EQ, in a domestically acceptable size.
I'd like to see a high efficiency, high Q, 12" coax with a good quality dome tweet that can keep up mounted in the middle instead of the pro compression tweeters that have to be padded down, to obtain the same point source sound as a true full ranger, but can make real bass in OB without needing a sub.
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