Dual 12" sub enclosure.

[BrickBait]

Goodday in here.

Happy to have joined this site after being on the sidelines for some time.

I have been thinking about trying to make a dual 12“ bassreflex enclosure with a very low profile, for PA use.
Sound quality is the primary objective, with good SPL and LF extension on a close second.

I am thinking of 38-40hz/-3dB.

Have heard BMS drivers and what they are capable of, So at this moment this will be my weapon of choice. But which model to go for is still undecided.

What do you All think? Is it doable?

 

[BrickBait]

Thank you for your reply, but that driver simpelt wont cut it. Powerhandling and sensitivity .

 

[kipman725]

Well there are two BMS 12" sub drivers and this one seems the best choice (larger voice coil):
http://www.bmsspeakers.com/fileadmin/bms-data/product_data_2012/bms_12n804_t_data_2012-01.pdf

B&C has this:
B&C Speakers

and there is always the LAB12 which has less power handling but more excursion. Best idea would be to simulate a variety of different drivers in your box design. You may find that the port is a significant portion of the box volume when sizing it appropriately to avoid excessive air speed at tuning.

Here is a commercial cab similar to what your going for:
dB v2

 

[Brian Steele]

Here is a commercial cab similar to what your going for:
dB v2

The drivers pictured on that page (particularly the side-view picture) suggests that those are Eminence Kappalite drivers (or a derivative) used in that sub.

I used the Kappalite 3012LF driver to update my POC #3. It's a nice driver, but I haven't had a chance to compare it to BMS or B&C equivalents. In any case, it's not often that you see a 12" pro audio driver designed for subwoofer duty.

 

[Brian Steele]

More info about the Kappalite 3012LF driver here - Eminence Kappalite 3012LF Neo 12" Speaker Driver

Resonant Frequency (Fs)37 Hz
DC Resistance (Re)5.60 ohms
Voice Coil Inductance (Le)0.98 mH
Mechanical Q (Qms)6.94
Electromagnetic Q (Qes)0.34
Total Q (Qts)0.32
Compliance Equivalent Volume (Vas)3.77 ft.³
Mechanical Compliance of Suspension (Cms)0.26 mm/N
BL Product (BL)16.7 Tm
Diaphragm Mass Inc. Airload (Mms)72g
Maximum Linear Excursion (Xmax)9.10 mm
Surface Area of Cone (Sd)545.4 cm²

Fs is low (37 Hz) and the Qts of 0.32 suggests that an EBS alignment or offset TL with a large vent might work well with this driver.

 

[kipman725]

The drivers pictured on that page (particularly the side-view picture) suggests that those are Eminence Kappalite drivers (or a derivative) used in that sub.

I used the Kappalite 3012LF driver to update my POC #3. It's a nice driver, but I haven't had a chance to compare it to BMS or B&C equivalents. In any case, it's not often that you see a 12" pro audio driver designed for subwoofer duty.

Assuming that the application isn't xmax limited and unlimited amplifier power is available I would expect about 3dB more from the BMS/B&C due to the greater power handling capability.

 

[Brian Steele]

I suspect that a pro audio subwoofer based on 12" drivers is likely to be Xmax-limited .

 

[BrickBait]

Regarding amplifier muscle, thats not an issue at all

I have started making a list of drivers i will try to sim and compare. But as allready stated, there is not many choices.
Not many drivers with good effiency, powerhandling, and xmax. Not to mention the abbility to low.

The JTR enclosure is a fine example of what i want to do, but with even lower profil really really low profile.

 

[kipman725]

Regarding amplifier muscle, thats not an issue at all

I have started making a list of drivers i will try to sim and compare. But as allready stated, there is not many choices.
Not many drivers with good effiency, powerhandling, and xmax. Not to mention the abbility to low.

The JTR enclosure is a fine example of what i want to do, but with even lower profil really really low profile.

could you fit a single 15" in your form factor? it could be more cost effective and give more output:
B&C Speakers
The suspension is very stiff so the driver could be mounted cone down.

 

[Brian Steele]

could you fit a single 15" in your form factor? it could be more cost effective and give more output:
B&C Speakers
The suspension is very stiff so the driver could be mounted cone down.

Qts on that driver is very low. Looks like it might be more suitable for higher-order designs.

 

[BrickBait]

15“ drivers just take up to much space for what i want to end up with. But you are right about that driver. It might give more output and cost less than a dual BMS solution.

My maximum height of the enclosure will not be more than 340mm. So even with 12“ units, its a tight fit.

 

[kipman725]

Qts on that driver is very low. Looks like it might be more suitable for higher-order designs.

it won't give a flat response in a ported box but efficiency (huge impedance peak) and maximum output will be very high for the size, the response is equalized in afterwards. Main downside is a lot of voltage swing is needed on the amp to get to max output (also its an expensive driver).

 

[BrickBait]

I am 100% comitted to dual 12“ bass reflex.
And i have just installed WinISD pro, so time to learn a bit about it.

But first i have a question.. what tuning frequency should i am for with the BMS 12n804? I want to have the best possible sound quality and flat response.
I Will be playing All kinds of music thrue them. Playback and live.

Keep in mind that i have never designed a enclosure before. So very much a newbie here

 

[kipman725]

I am 100% comitted to dual 12“ bass reflex.
And i have just installed WinISD pro, so time to learn a bit about it.

But first i have a question.. what tuning frequency should i am for with the BMS 12n804? I want to have the best possible sound quality and flat response.
I Will be playing All kinds of music thrue them. Playback and live.

Keep in mind that i have never designed a enclosure before. So very much a newbie here

Use hornresp, traditional maximum output box is tuned to Fs.