I build music studios, and I build speakers, when I can't afford to buy commercially available studio monitors. I know very little about the subject, but have had some success at implementing other people's designs.
The external dimensions of the subwoofer are more or less fixed at 30"h x 25"w x 27"d (about 11.7 cu. ft.)... This is because it serves as the stand for the mains (satellites). The whole setup will will be placed flush with the front wall at an equilateral triangle terminating just behind the engineer's head. This is for a music studio being built according to ITU recommendations.
The LAB12 is available locally at a reasonable price... There is only a small percentage of manufacturers represented here in India, and shipping and customs will become prohibitively expensive, if we were to import drivers. In my search so far, this Eminence has turned out to be the most promising candidate.
The attached images are self explanatory.
I want to achieve 110 dB, ~25 Hz - 100 Hz, as clean and tight as possible.
I'm mildly familiar with WinISD but it is refusing to validate the T/S parameters supplied by Eminence - and anyway, I reach the threshold of my understanding quite quickly.
So - given the space and driver I have available, what would be the best way to accomplish my goal? I would like to go sealed (with a little equalization, if necessary) - but with my extremely limited knowledge, I'm guessing it is going to quite difficult.
Class D amps of whatever required wattage and any reasonable amount of digital equalization will be made available.
How do I get to where I want to go?
The external dimensions of the subwoofer are more or less fixed at 30"h x 25"w x 27"d (about 11.7 cu. ft.)... This is because it serves as the stand for the mains (satellites). The whole setup will will be placed flush with the front wall at an equilateral triangle terminating just behind the engineer's head. This is for a music studio being built according to ITU recommendations.
The LAB12 is available locally at a reasonable price... There is only a small percentage of manufacturers represented here in India, and shipping and customs will become prohibitively expensive, if we were to import drivers. In my search so far, this Eminence has turned out to be the most promising candidate.
The attached images are self explanatory.
I want to achieve 110 dB, ~25 Hz - 100 Hz, as clean and tight as possible.
I'm mildly familiar with WinISD but it is refusing to validate the T/S parameters supplied by Eminence - and anyway, I reach the threshold of my understanding quite quickly.
So - given the space and driver I have available, what would be the best way to accomplish my goal? I would like to go sealed (with a little equalization, if necessary) - but with my extremely limited knowledge, I'm guessing it is going to quite difficult.
Class D amps of whatever required wattage and any reasonable amount of digital equalization will be made available.
How do I get to where I want to go?
Attachments
For starters, there's a 'sticky' thread devoted to stored WinISD Pro or v0.7 driver files as well as a good tutorial, so download the .wdr file to its 'driver' folder and play with it a bit.
Downloadable WinISD Pro Files - Home Theater Forum and Systems - HomeTheaterShack.com
WinISD Pro Tutorial and Download (A detailed guide on how to use WinISD Pro) - Home Theater Forum and Systems - HomeTheaterShack.com
http://www.hometheatershack.com/for...loadable-winisd-pro-files-eminence-lab-12.wdr
GM
You can use published specs for simulation. If it looks acceptable then measure the real drivers parameters and work it out again before making a box. I have a Lab12 in a cube about 15x15x15 and measured OK if I remember right. I'm out of town and cannot give more accurate info now.
I can give you the measured parameters of the driver I have and that has been run in about 24 hours with a LF test signal. Only after 5th Jan.
I can give you the measured parameters of the driver I have and that has been run in about 24 hours with a LF test signal. Only after 5th Jan.
Hi audiothings,
Using WinISD Pro and WinISD 0.7 with the build in T/S parameters for the LAB 12, and alignment: "0.707 Max flat amplitude response" I get an recommended V_net_internal=53.15L.
This driver is very forgiving to the volume in a sealed enclosure. Your indicated box dimensions will give you about V_net_int=280L(?), so you have more than enough volume for two drivers. I would recommend you build your box w/ an internal volume of about Vnet=70L/per driver; Vnet means the gross internal volume minus the volume displaced by the driver, bracing, amplifier or whatever else may be inside the box.
As an additional note: do yourself a favor, and learn to use Hornresp in addition to your other favorite simulation programs:
Hornresp
It will simulate open baffles as well as closed and vented boxes in addition to horns and quarter-wave enclosures.
Regards,
Using WinISD Pro and WinISD 0.7 with the build in T/S parameters for the LAB 12, and alignment: "0.707 Max flat amplitude response" I get an recommended V_net_internal=53.15L.
This driver is very forgiving to the volume in a sealed enclosure. Your indicated box dimensions will give you about V_net_int=280L(?), so you have more than enough volume for two drivers. I would recommend you build your box w/ an internal volume of about Vnet=70L/per driver; Vnet means the gross internal volume minus the volume displaced by the driver, bracing, amplifier or whatever else may be inside the box.
As an additional note: do yourself a favor, and learn to use Hornresp in addition to your other favorite simulation programs:
Hornresp
It will simulate open baffles as well as closed and vented boxes in addition to horns and quarter-wave enclosures.
Regards,
Attachments
Ashok,
I'll be glad to have access to your measurements. I don't mean to be racist, but are you also in India?
tb46,
Thank you. I have simulated it in WinISD - it is looking good fromm where I'm at, but there are so many things I don't understand...
Since I have ~280L available and you are suggesting the usage of 70L per driver, I'm picking up that there is an optimal size for a sealed cabinet and anything more will be detrimental. Is this true?
GM,
I do, over time intend to get into loudspeaker design sincerely. But these speakers will likely get built in the next three months and I'm not going to kid myself into thinking that I would have figured it all out by then. I'm struggling to wrap my head around the multiple things I have already taken on - and the futility of trying to to understand everything about something is weighing me down...
I'm hoping that there is somebody out there for whom this is easy... Somebody who'll say "What? 2 Lab 12's in a 11 cu. ft. sealed cab? No problem, just add X dB filter at Y frequency and feed it with an amp that puts out Z watts. You'll get your 110 dB, ~25 Hz - 100 Hz, clean and tight."
I know its not going to be as easy as this, but a man can hope
I'll be glad to have access to your measurements. I don't mean to be racist, but are you also in India?
tb46,
Thank you. I have simulated it in WinISD - it is looking good fromm where I'm at, but there are so many things I don't understand...
Since I have ~280L available and you are suggesting the usage of 70L per driver, I'm picking up that there is an optimal size for a sealed cabinet and anything more will be detrimental. Is this true?
GM,
I do, over time intend to get into loudspeaker design sincerely. But these speakers will likely get built in the next three months and I'm not going to kid myself into thinking that I would have figured it all out by then. I'm struggling to wrap my head around the multiple things I have already taken on - and the futility of trying to to understand everything about something is weighing me down...
I'm hoping that there is somebody out there for whom this is easy... Somebody who'll say "What? 2 Lab 12's in a 11 cu. ft. sealed cab? No problem, just add X dB filter at Y frequency and feed it with an amp that puts out Z watts. You'll get your 110 dB, ~25 Hz - 100 Hz, clean and tight."
I know its not going to be as easy as this, but a man can hope
Here is something you can do with a Lab12 and about 2.1cu ft.
http://www.diyaudio.com/forums/subwoofers/259509-new-sub-design-constricted-transflex-simple-build-series-tuned-6th-order-80.html#post4178367
http://www.diyaudio.com/forums/subwoofers/259509-new-sub-design-constricted-transflex-simple-build-series-tuned-6th-order-80.html#post4178367
Lab 12 measured parameters
Fs = 22.64 Hz
Qms = 15.28
Vas = 113.3 liters
Cms = 0.34 mm/N
Mms = 146.8 g
Rms = 1.353 kg/s
P-Dia = 248.3 mm ( eff)
Sd = 484.3 sq.cm ( eff)
Qes = 0.38
Re = 4.7 ohms
Le = 0.97 mH
Z = 5.64 ohms
BL = 16.07 Tm
Qts = 0.371
no = 0.334 %
1-W SPL = 87.38 dB
2.83-V SPL = 89.69 dB
I have only one driver !
Fs = 22.64 Hz
Qms = 15.28
Vas = 113.3 liters
Cms = 0.34 mm/N
Mms = 146.8 g
Rms = 1.353 kg/s
P-Dia = 248.3 mm ( eff)
Sd = 484.3 sq.cm ( eff)
Qes = 0.38
Re = 4.7 ohms
Le = 0.97 mH
Z = 5.64 ohms
BL = 16.07 Tm
Qts = 0.371
no = 0.334 %
1-W SPL = 87.38 dB
2.83-V SPL = 89.69 dB
I have only one driver !
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