Help finding 12" or 15" underhung drivers
Hi everyone,
I'm currently looking for bass or mid-bass drivers for a precise Hi-Fi application. This drivers will have to meet the following requirements (from more to less important) :
Main requirements :
- Size : 12" or 15" (not less, not more)
- Underhung motor
Secondary requirements :
- High BL
- Rigid membrane (but still light - we're not looking for real SUBs here !)
- Low Rms
- High Cms
- Xmax not too big
- High BL/Mms
Can you please help ? If we could only list the major 12" and 15" driver manufacturers that use underhung motors, that would be a good start.
Thanks in advance,
Jose
Hi everyone,
I'm currently looking for bass or mid-bass drivers for a precise Hi-Fi application. This drivers will have to meet the following requirements (from more to less important) :
Main requirements :
- Size : 12" or 15" (not less, not more)
- Underhung motor
Secondary requirements :
- High BL
- Rigid membrane (but still light - we're not looking for real SUBs here !)
- Low Rms
- High Cms
- Xmax not too big
- High BL/Mms
Can you please help ? If we could only list the major 12" and 15" driver manufacturers that use underhung motors, that would be a good start.
Thanks in advance,
Jose
Hi MJL21193, thanks. Aurasound drivers are beautiful, but their membranes are WAY too heavy, and their BLs are too low. These are real SUBs (low Fs, heavy membranes to lower Fs, low VAS to keep them "WAF compliant", very high Xmax...), and that's not what we want here.
Maybe I should explain just a bit : I'm a part of a small team working on a High-end, Home-Hifi, 3/4-way active, speaker project (max SPL about 105dB, not more, everything software-EQ'ed with IZotope Ozone). We are aiming to find some of the best modern drivers the technology has to offer today, regardless of their cost (well, *almost* regardless of course, lol - let's say about $4-5K for all the drivers, that's our budget). For example, for the mid we will probably work with the Accuton C90-T6, which seems to be just one of the best modern mids out there. Now we are aiming to find a bass or mid-bass driver that will go up to 200-250 Hz and catch up very nicely with the Accuton.
For this, our choices are as follows :
- 12" or 15" : not more than 15" because most 18" drivers will have trouble going up to 200-250 Hz. And not less because subjectively we do not want less than 12".
- Electromechanical specs close to Accuton's ones (this includes a rigid membrane, a high BL but also a quite low Mms, a low Rms, a underhung motor, etc.). Yeah, too bad Accuton doesn't make 12" drivers yet. ;-)
- The frequencies below 50Hz aren't really a problem, because either the driver can make them while going up to 200-250Hz, or else we will go 4-way with a real sub below (and that's probably what we'll end up doing). The priority is up, not down.
The aim of this topic will not be to question these choices (although you can ask questions if you want of course), but rather to see if there really are some High-End 12" or 15" drivers out there that will meet our requirements. They might be Hi-Fi drivers or Pro sound/Studio drivers / etc., we don't care because we are quite cartesian people and we mainly believe in the technical specs (physics are physics, no miracles), in the optimization process and in the final results.
Of course we're not professional people and we can make mistakes. But hey, that's just part of the fun of it don't you think ? ;-)
Thanks in advance.
Maybe I should explain just a bit : I'm a part of a small team working on a High-end, Home-Hifi, 3/4-way active, speaker project (max SPL about 105dB, not more, everything software-EQ'ed with IZotope Ozone). We are aiming to find some of the best modern drivers the technology has to offer today, regardless of their cost (well, *almost* regardless of course, lol - let's say about $4-5K for all the drivers, that's our budget). For example, for the mid we will probably work with the Accuton C90-T6, which seems to be just one of the best modern mids out there. Now we are aiming to find a bass or mid-bass driver that will go up to 200-250 Hz and catch up very nicely with the Accuton.
For this, our choices are as follows :
- 12" or 15" : not more than 15" because most 18" drivers will have trouble going up to 200-250 Hz. And not less because subjectively we do not want less than 12".
- Electromechanical specs close to Accuton's ones (this includes a rigid membrane, a high BL but also a quite low Mms, a low Rms, a underhung motor, etc.). Yeah, too bad Accuton doesn't make 12" drivers yet. ;-)
- The frequencies below 50Hz aren't really a problem, because either the driver can make them while going up to 200-250Hz, or else we will go 4-way with a real sub below (and that's probably what we'll end up doing). The priority is up, not down.
The aim of this topic will not be to question these choices (although you can ask questions if you want of course), but rather to see if there really are some High-End 12" or 15" drivers out there that will meet our requirements. They might be Hi-Fi drivers or Pro sound/Studio drivers / etc., we don't care because we are quite cartesian people and we mainly believe in the technical specs (physics are physics, no miracles), in the optimization process and in the final results.
Of course we're not professional people and we can make mistakes. But hey, that's just part of the fun of it don't you think ? ;-)
Thanks in advance.
I don't have any off-the-shelf recommendations, but Morel, a large manufacturer, makes Supremo car components with an underhung voice coil up to 8"
http://www.morelhifi.com/products/mob_2way_supremo.html
Since Morel also makes 12" drivers and is generally regarded as a very respected hi-fi manufacturer generally, you might want to give them a call and see what they can offer in a very short production run of a few woofers.
Who knows, maybe they might get enthusiastic about the project and work with you on this. No guarantees, but they certainly seem to have the capabilities you would need for this, if you can't find suitable production models.
http://www.morelhifi.com/products/mob_2way_supremo.html
Since Morel also makes 12" drivers and is generally regarded as a very respected hi-fi manufacturer generally, you might want to give them a call and see what they can offer in a very short production run of a few woofers.
Who knows, maybe they might get enthusiastic about the project and work with you on this. No guarantees, but they certainly seem to have the capabilities you would need for this, if you can't find suitable production models.
I had not seen that the BD-bass is underhung, nice but designed to give high SPL with high Fs
These 38EX and 46EX will be be very expencive
http://www.jlbcreations.com/Fertin/produits_hp.asp
And this one might be interesting
http://www.aer-loudspeakers.com/eng/sc12-e.htm
These 38EX and 46EX will be be very expencive
http://www.jlbcreations.com/Fertin/produits_hp.asp
And this one might be interesting
http://www.aer-loudspeakers.com/eng/sc12-e.htm
Thanks for your answers.
@kelticwizard : Morel doesn't seem to make drivers bigger than 10" (see http://www.morelhifi.com/products/raw_woofers.html ).
@Peter M. : YES, the BD15 could be a good choice.
I had already seen its specs, and I think we're going to take a very close look at it. It could be a winner !!
@tinitus : what problem do you see with the BD15 ? We don't need a low Fs because there will probably be a subwoofer below. And we only need 105dB. Again, we are looking for a bass or mid-bass driver that will go up to 200-250 Hz and catch up very nicely with the Accuton. And for that, the BD15 is looking good, don't you think ?
Yes, the Fertin are very renowned here in France... but you're right, they're very expensive (about €920 each, that's $1250 each !). Let's say they're too expensive for us.
As for the AER... it really is a SUBwoofer, probably with a heavy membrane, and besides it has a small Vas (WAF-oriented driver ? ) which also means a small Cms. I don't think it will do.
@everyone : now that we see that the BD-Design BD15 can be a potential winner, do you see any other similar drivers ? What about the JBL 1500AL for example ? Looks very nice but... it just seems impossible to find one anywhere ! (if you have any URLs...).
Thanks.
@kelticwizard : Morel doesn't seem to make drivers bigger than 10" (see http://www.morelhifi.com/products/raw_woofers.html ).
@Peter M. : YES, the BD15 could be a good choice.
I had already seen its specs, and I think we're going to take a very close look at it. It could be a winner !!@tinitus : what problem do you see with the BD15 ? We don't need a low Fs because there will probably be a subwoofer below. And we only need 105dB. Again, we are looking for a bass or mid-bass driver that will go up to 200-250 Hz and catch up very nicely with the Accuton. And for that, the BD15 is looking good, don't you think ?
Yes, the Fertin are very renowned here in France... but you're right, they're very expensive (about €920 each, that's $1250 each !). Let's say they're too expensive for us.
As for the AER... it really is a SUBwoofer, probably with a heavy membrane, and besides it has a small Vas (WAF-oriented driver ?
) which also means a small Cms. I don't think it will do.@everyone : now that we see that the BD-Design BD15 can be a potential winner, do you see any other similar drivers ? What about the JBL 1500AL for example ? Looks very nice but... it just seems impossible to find one anywhere ! (if you have any URLs...).
Thanks.
I assume you believe that relatively high Mms means... poorer performance? In what way?
As far as the gap type goes, underhung/SGLC is merely a method to attain a flatter BL(x) function. Overhung configurations can also achieve a fairly flat BL(x) WITHIN a certain excursion. If you calculate the required excursion for your max SPL, you will find the necessary limit within which the BL(x) must be flat.
Or, since nonlinear BL(x) mostly (only?) affects nonlinear distortion, just look for a driver with minimal low-end distortion. Mid- and high-end distortion is less affected by nonlinear BL(x) because excursion lowers as frequency increases, and BL(x) tends to be flatter as you restrict the excursion.
A rigid membrane is not necessary. Again, just look at the numbers.
High BL is nice, and so is a high BL/Mms ratio, but instead of looking for those figures, you could just look for high sensitivity.
Even if you ignore everything I mentioned above, I would strongly advise that you consider well the good PA drivers, like from JBL, 18Sound, etc. The JBL 2242H, in particular, looks like an excellent driver, with predominantly (and still very low) 2nd-order HD throughout most of the midrange, at 80W, even.
As far as the gap type goes, underhung/SGLC is merely a method to attain a flatter BL(x) function. Overhung configurations can also achieve a fairly flat BL(x) WITHIN a certain excursion. If you calculate the required excursion for your max SPL, you will find the necessary limit within which the BL(x) must be flat.
Or, since nonlinear BL(x) mostly (only?) affects nonlinear distortion, just look for a driver with minimal low-end distortion. Mid- and high-end distortion is less affected by nonlinear BL(x) because excursion lowers as frequency increases, and BL(x) tends to be flatter as you restrict the excursion.
A rigid membrane is not necessary. Again, just look at the numbers.
High BL is nice, and so is a high BL/Mms ratio, but instead of looking for those figures, you could just look for high sensitivity.
Even if you ignore everything I mentioned above, I would strongly advise that you consider well the good PA drivers, like from JBL, 18Sound, etc. The JBL 2242H, in particular, looks like an excellent driver, with predominantly (and still very low) 2nd-order HD throughout most of the midrange, at 80W, even.
I see no problem with the BD15, and believe it to be a very nice driver at a fair price .... but you didnt mention anything about using subs
JBL 1500AL will probably cost almost like the Fertins
AER, I dont think that SPL of 97db with a 12" points in direction of a subdriver or heavy membrane, at all .... but low Fs of 25hz is more likely achieved by soft surround/spider
I dont know about your design ideas, but the moderate VAS would be very helpfull in a multi way system, especially if its a 4way, otherwise your cabinet will become unrealistic big and drivers too wide apart, or wrong listening height etc.
JBL 1500AL will probably cost almost like the Fertins
AER, I dont think that SPL of 97db with a 12" points in direction of a subdriver or heavy membrane, at all .... but low Fs of 25hz is more likely achieved by soft surround/spider
I dont know about your design ideas, but the moderate VAS would be very helpfull in a multi way system, especially if its a 4way, otherwise your cabinet will become unrealistic big and drivers too wide apart, or wrong listening height etc.
BTW... PrecissionDevices has made a new 18BN40 (or something like that), especially made fore studio sound with smooth and well controlled high end, and I think theres a similar 15" too
But its a question how such big drivers will mate with a "small" Thiel with ceramic cone
You seem to think that picking drivers with the most advanced technology and best specs will give you the best sound - if only speaker design were that simple
But its a question how such big drivers will mate with a "small" Thiel with ceramic cone
You seem to think that picking drivers with the most advanced technology and best specs will give you the best sound - if only speaker design were that simple
Some positive considerations...
You want subs .... and a midbass up to 200hz ??
I take it the subs should roll off above 40 ...or else I dont think it makes sense to have the midbass ?
Point is that any 12-15" PA drivers will roll of before that ... too high Fs
thats why I recommended one of the AER drivers with low Fs ..... and they are really NOT sub drivers .... look at the sensitivity
With a PrecissionDevices 18BR40 (?), or the AER 12" car woofer.... it could even work with out subs
Now, you might think that Fertin drivers are expencive, and indeed they are ....but try and calculate the cost of 2 high quality 12-15" and 2 additional and expencive sub drivers with amps .... my guess is that it will cost just as much
Remember that good sound often comes from very simple designs
You want subs .... and a midbass up to 200hz ??
I take it the subs should roll off above 40 ...or else I dont think it makes sense to have the midbass ?
Point is that any 12-15" PA drivers will roll of before that ... too high Fs
thats why I recommended one of the AER drivers with low Fs ..... and they are really NOT sub drivers .... look at the sensitivity
With a PrecissionDevices 18BR40 (?), or the AER 12" car woofer.... it could even work with out subs
Now, you might think that Fertin drivers are expencive, and indeed they are ....but try and calculate the cost of 2 high quality 12-15" and 2 additional and expencive sub drivers with amps .... my guess is that it will cost just as much
Remember that good sound often comes from very simple designs
@Michail Bulgaria : thanks, I'll take a look at audiotechnology. However, their price list seems quite expensive (700€ for a single 15F102, that's $930 - add VAT and we are at 840€ / $1120 each !). Maybe a 12", who knows.
@454Casull : I agree with your explanations on the underhung motors. For me underhung is more like the icing on the cake. But I have decided to put it as a main requirement in this topic, just because underhung drivers are quite difficult to find and we needed ideas. Of course there are more important things than the underhung motor.
We can also look for drivers with minimal low-end distortion. However, accurate distorsion information is not always easy to find (unfortunately). A lot of manufacturers just don't give the information. Does that mean that they make bad drivers ? Not necessarily.
But well, like I said we are not going to open a wide discussion on acoustics fundamentals here. Please understand that our current choices are the result of a very long team work in another forum (about 50 pages). So, just to quickly answer your questions :
- We don't believe that a high Mms means poorer performance : a high Mms can help lower Fs and make the membrane even more rigid, so that's good. However, in our particular application, we don't want a too high Mms because of our choice to have electromechanical specs close to those of the Accuton mid in order to smooth the transition. That's all.
- As for the BL/Mms, well, it really is like the Loch Ness monster : some believe in it, and some don't. IMHO the BL is more important than the BL/Mms itself. Some quite serious guys like the ones at Precision Devices even use the BL alone as a marketing argument ! (e.g. "A B/L in excess of 27 T/m for fast acurate lows" : precisiondevices site, /showdetails.asp?id=73 ).
Of course we could discuss endlessly on this subject, but we do believe that a rigid AND quite light membrane is better in our case, even for a bass driver (that's also Accuton's approach, just take a look at their bass drivers). That really is our choice.
Remember, we're not looking for the ultimate SUBwoofer here. We're looking for the best bass drivers up to 200-250Hz. And sound quality at 200-250Hz is more important to us than sound quality below 50Hz.
Of course we haven't forgotten tha good PA drivers, you are totally right. But as for the JBL 2242H, it's a 18" and we're looking for a 15" or 12". There are however other JBL models that could be more appropriate IMHO : 2220J, 2220B, 1500AL... if only I knew where to find them !! (any help appreciated)
@tinitus & MJL21193 : of course it's not that simple. There's a lot of work in the measuring / optimization process, and we have not forgotten that. Thank you.
@tinitus : we are looking for a bass/midbass up to 200-250, and down to 50-40. A real sub (JBL W15GTi, Adire Tumult, Beyma 18LX60...) will take care of the low frequencies. These subs can go up to 50-60 without problems, so the active crossover won't be too difficult. But that's another story.
Oh, BTW there will be only one mono sub. There is no interest in having two subs because there's no real stereo under 40-50 Hz. So don't worry, it won't cost as much as two Fertin's. And as for the amps, we already have all of them.
@454Casull : I agree with your explanations on the underhung motors. For me underhung is more like the icing on the cake. But I have decided to put it as a main requirement in this topic, just because underhung drivers are quite difficult to find and we needed ideas. Of course there are more important things than the underhung motor.
We can also look for drivers with minimal low-end distortion. However, accurate distorsion information is not always easy to find (unfortunately). A lot of manufacturers just don't give the information. Does that mean that they make bad drivers ? Not necessarily.
But well, like I said we are not going to open a wide discussion on acoustics fundamentals here. Please understand that our current choices are the result of a very long team work in another forum (about 50 pages). So, just to quickly answer your questions :
- We don't believe that a high Mms means poorer performance : a high Mms can help lower Fs and make the membrane even more rigid, so that's good. However, in our particular application, we don't want a too high Mms because of our choice to have electromechanical specs close to those of the Accuton mid in order to smooth the transition. That's all.
- As for the BL/Mms, well, it really is like the Loch Ness monster : some believe in it, and some don't. IMHO the BL is more important than the BL/Mms itself. Some quite serious guys like the ones at Precision Devices even use the BL alone as a marketing argument ! (e.g. "A B/L in excess of 27 T/m for fast acurate lows" : precisiondevices site, /showdetails.asp?id=73 ).
Of course we could discuss endlessly on this subject, but we do believe that a rigid AND quite light membrane is better in our case, even for a bass driver (that's also Accuton's approach, just take a look at their bass drivers). That really is our choice.
Remember, we're not looking for the ultimate SUBwoofer here. We're looking for the best bass drivers up to 200-250Hz. And sound quality at 200-250Hz is more important to us than sound quality below 50Hz.
Of course we haven't forgotten tha good PA drivers, you are totally right. But as for the JBL 2242H, it's a 18" and we're looking for a 15" or 12". There are however other JBL models that could be more appropriate IMHO : 2220J, 2220B, 1500AL... if only I knew where to find them !! (any help appreciated)
@tinitus & MJL21193 : of course it's not that simple. There's a lot of work in the measuring / optimization process, and we have not forgotten that. Thank you.
@tinitus : we are looking for a bass/midbass up to 200-250, and down to 50-40. A real sub (JBL W15GTi, Adire Tumult, Beyma 18LX60...) will take care of the low frequencies. These subs can go up to 50-60 without problems, so the active crossover won't be too difficult. But that's another story.
Oh, BTW there will be only one mono sub. There is no interest in having two subs because there's no real stereo under 40-50 Hz. So don't worry, it won't cost as much as two Fertin's. And as for the amps, we already have all of them.
Lower cost Aura might work:
http://www.madisound.com/cgi-bin/index.cgi?cart_id=7318462.7990&pid=2096
Don't know your requirements but pairs of this 12" or the similar 10" might fit your application.
Pete B.
http://www.madisound.com/cgi-bin/index.cgi?cart_id=7318462.7990&pid=2096
Don't know your requirements but pairs of this 12" or the similar 10" might fit your application.
Pete B.
Your looking at Bl which combined with moving mass and radiating area determine the driver pass band sensitivity.
What are your voltage sensitivity and impedance requirements?
This will help you determine the actual required parameters and not just more is better.
What type of loading are you using and what is the maximum
enclosure volume you can provide?
Pete B.
What are your voltage sensitivity and impedance requirements?
This will help you determine the actual required parameters and not just more is better.
What type of loading are you using and what is the maximum
enclosure volume you can provide?
Pete B.
Hi everyone. I have just received an answer from a friend of mine, Agnostic1er, who is also a part of the project. Agnostic1er has a lot (and I mean a LOT) more knowledge than myself in acoustic matters. So here's his answer (bold) to Casull454 :
Again, let's remember that the purpose of this topic is NOT for us to justify all of our choices. I have posted this answer for information purposes only. Thanks for your understanding.
@P2B : we'll chose the type of loading after the driver. And we do not have any particular volume limitations because the bass enclosures will be totally independant from the mid-tweeter enclosures. All right, let's say 300L max per bass enclosure, just to give an idea.
Again, let's remember that the purpose of this topic is NOT for us to justify all of our choices. I have posted this answer for information purposes only. Thanks for your understanding.
@P2B : we'll chose the type of loading after the driver. And we do not have any particular volume limitations because the bass enclosures will be totally independant from the mid-tweeter enclosures. All right, let's say 300L max per bass enclosure, just to give an idea.
http://www.iconicspkrs.com/downloads/165series.pdf
The above are made from the original Altec 515G tooling by former Altec employees. I'm using a pair of the orignal Altec 515-16G and I have to say they are the best 15" drivers I have heard in the mids.
I have them in 160 litre boxes tuned to 45Hz at the moment. This is obviously not ideal, but the boxes were free. Not much bass below 50Hz, but they have a lot of kick and speed.
The above are made from the original Altec 515G tooling by former Altec employees. I'm using a pair of the orignal Altec 515-16G and I have to say they are the best 15" drivers I have heard in the mids.
I have them in 160 litre boxes tuned to 45Hz at the moment. This is obviously not ideal, but the boxes were free. Not much bass below 50Hz, but they have a lot of kick and speed.
i am using a phl in a bass guitar cabinet. the phl 5200. its over hung but the inductance isn't too bad and it has fantastic clean output. 97db efficient. there are probably other 15 inch drivers or 12's that would better suite your application from phl. www.phlaudio.com
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