[matcartier]

I know this may be straying away from true DIY but I figured it'd be the best place to start... I recently came upon some of these subs in a state lot. I currently have three sets of them. I figure ill use two in my ht and keep one for parts. The unit itself is 3 x 12" in a vented trapezoidal box. The cabinet itself is 1/2" baltic birch "extensively braced" and the literature that i've seen on it says that each driver is in a separate vented sub-enclosure. The specs for the system (most of these numbers are gibberish to me) are as follows:

Freq. Resp (1W @ 1m): +- 3db 50hz to 1.6kHz, -10 db 40 Hz

Axial sensitivity (db spl, 1 watt @ 1 m): LF 100

Impedance: LF 3 x 8 ohms

Power handling, AES Standard: LF 1500 w

Calculated Max output (db spl): LF peak - 137.8, LF long term - 131.8

Nominal coverage angle/ -6dbs: Horiz 160*, Vert 60*

Recommended high pass: 24 db/octave 40hz


The dimensions of the unit are 40" tall, 21" deep, 24" wide frontside 12 3/4 wide in back.


I'm trying to find a way to integrate this into my HT, I'm thinking if I buy an iNUke 12000dsp I could power two of these. My concern is that the output really starts to roll of at 50Hz. Am i wrong or is this awfully high for a sub? Am i just expecting too much out of three 12's? Should i find a way to seal the box? Should i gut all three and make one big frankenstein sub? I really don't know what i'm doing but feel like it would be a huge waste to not at least try to do something bada** with them. Also the guy i got them from insisted that they have been tested and "work".


Thanks in advance

Mat

 

[dmadesign]

I don't believe those are subs. It looks like they are just woofers.

 

[LTD02]

 http://eaw.com/docs/2_Legacy_Products/Loudspeakers/MQ/MQ1312/MQ1312_SPECS_rev1.pdf


its just three 12" woofers in a ported cab. probably tuned to around 50hz or so. that could be used as a "sub" in a pro audio setting in days gone past, but even today, most pro subs would be tuned a little lower. it is also designed to be played up to 1600hz or so.


it should cover the 50-150hz region very well if you wanted to make a "mid bass module" out of it.

 

[matcartier]

Is there any other way to salvage them? can i yank out the drivers and make a subwoofer with them or does a 12 (looks like it doesn’t have much excursion...) just not move enough air. I’m not against building a new cabinet for the drivers or modifying the existing one... I’m also not against buying different drivers to use in this cabinet (or a modified version of it). Are these things possible? Can i find a way to tune these cabinets to go lower? These things came free to me and I’d really like to find a use for them that doesn’t go away when I add a legitimate sub to the system.

 

[LTD02]

the drivers probably only have a very limited excursion, which is fine for the cab that they are in. re-tuning the cab or building a new cab lower is possible, but the maximum spl before the drivers run out of excursion will drop quite a bit. that's the tradeoff.

 

[LTD02]

for an illustrative example: here is the eminence kappalite 12" lf low frequency pro audio driver, x3 in a 5 cubic footer tuned to 45hz.


that "dip" is where the drivers are running out of excursion.




reconfiguring for a 22hz tuning in an 8 cubic footer, which would be decent for home theater gives this max spl:




so it can be seen that by going with the lower tuning, much lower frequencies can by played at high level. however, the tradeoff is that the middle of the bass will not have as much output potential as the cab with the higher tuning. that is not unique to those drivers. that is how it works for all ported cabs.


with those drivers, if you want high spl low end bass, sealed is pretty much out of the question. max spl would be about 10db or so lower than the ported design around the tuning frequency.


I have no idea what driver that sub uses, but it is likely quite similar to the driver modeled.


note: these are not "frequency response" plots. these are "maximum spl" plots to show at what spl and frequency the drivers will be hitting xmax.

 

[matcartier]

Well i guess i didn't strike gold with this find... If i keep it the way that it is am wrong in thinking that using a single amp channel to power a single 3 driver cabinet will give me a 2 ohm load? And if that is the case the iNuke 6000 isn't rated for that, but the iNuke 3000 is (2x 1500w @ 2 ohms). I don't know what AES standard is but I saw 1500 watts somewhere on that spec sheet. Is that amp (3000) capable of properly powering a pair of those units? I've heard elsewhere on this forum that a 2 ohm load is bad. Sorry if these questions are dumb but... well... I'm pretty dumb when it comes to this stuff.

Thanks

Mat

 

[LTD02]

"Well i guess i didn't strike gold with this find..."


115db is full reference...in the right cab, i bet you would be surprised.


that plot also doesn't consider room gain or the second sub, which will add another 6db or so.


if the drivers are 8 ohm, 3 in parallel will give 2.67 ohms.


if you set the limiter to 1500 watts into 2.67 ohms (63 volts), the 6000 should be fine with one group of three on each channel, as that draws the same 24 amps as 2200 watts into 4 ohms.

 

[matcartier]

Thats what I'll do then... Thanks for the help... also big fan of the avatar.