Under cabinet sub help for a newbie

Hello all,
I just found the drivers below on clearance on parts-express:

4" x 6" High Excursion Poly Cone Woofer with Neodymium Magnet

....and thought given the cost that I might be able to use them to build a slim but long sub to fit under a cupboard (big piece of furniture, photo attached...I think).

My thought is to build an enclosure which is trapezoidal in cross section, sort of a wedge, so that the woofers are firing at an angle downward toward the floor and into the room, so the whole thing will be more or less unseen.

The space I have to work with is 13" deep, 4.5" tall, and 59" wide.

Would these woofers be worth a shot? Sealed/ported? Firing together or push/pull? All for music - chamber music, jazz, orchestral, folk mostly, so I'd like it nimble and clean-sounding.

I don't know anything about building yet but I learn quickly - point me in the right direction!

Many thanks for your expertise and advice!
 

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GM

Member
Joined 2003
Yes, you'll need to, what with the abysmal efficiency. This one requires a little thought, so will have to get back to you as time permits. Got some storm damage to deal with first.

Do you have, or got the budget for DSP to EQ, time delay [TD] this 'sub'?

GM
 
Small drivers suitable for bass will all have abysmal efficiency, but doesn't hurt to look around as it may save me or others some time.

Not per se, but in recent years have had enough damage that I can't recover before I'm hit again, undoing some of the partially repaired and forced to have a very high insurance deductible, so no help there.

GM
 
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I think you just combine enough of them to get the efficiency up to where it matches? Or live with the lower limited one and gain down the higher.

I happen to have been window shopping those drivers and modelling them in winISD. I just got a dayton dspK+KE for dsp so I'm dreaming of future budget projects. It's 30 bucks plus 25 one time for a programmer board. I'm a complete noob so take it all with a grain of salt!

A sealed box extending 24" back from the driver faceplace (6x4x24 internally; it was a convenient dimension to imagine) has only a mild peak at 70 hz to eq out, and can be flattened to ~32hz with 6.5 db of boost at 30 hz, q of 2. If I got the power calculations right, that takes 4.5x the power, so I entered 25w/4.5=5.5w signal in winISD. (Insert picture of dog at desk, because I don't know what I'm doing here. But I figured I had to compensate for the boost EQ somewhere, and this is it?)

It gets an f3 of about 32hz, 83db at power limits, and is nowhere close to excursion limited at any frequency, so no high pass needed. 2 in parallel with (2x volume) gives a reasonable 3ohm-ish load if your amp is 2ohm stable; and should gain 6db?

6 per side in series-parallel for either 4 or 8 ohms at your preference, could be interesting at the price. Also you could use 6 in isobaric with 3/2=1.5x the box volume of a single (though only the output of 3 in full size boxes). I don't know how much louder those options would be.

Etc section:
Ported/passive radiator was basically terrible at any tuning, imo.

I can't remember how big it had to be to flatten out naturally. It would be easy to find out. I also modeled some even smaller boxes which were decent to ~40hz, but they seemed to lose a lot of dbs going much smaller than the above, and the peak gets nasty. Happy to share details.

These seems like they would be naturally weather resistant if faced down to keep sun away and water from building up, given the poly cone and rubber surround.

I'd love to know if I created my driver file correctly. (attached, renamed to .txt)

I have no idea how high these might play, as winISD doesn't model anything except the bottom of the bandwidth, as I recall.

The power handling seemed to indicate these wouldn't do real subbass at a nice level with any reasonable number of drivers even with all dat excursion.
 

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Isobaric sounds like an interesting idea, thanks. Should help since I have space restrictions.

Speakers I'm mating to are nothing special at all, JBL 500 bookshelf speakers. Think I'll build a pair of simple single driver speakers in a BR enclosure soon. Any suggestions for drivers are welcome, Fostex, Diatone clone, Dayton, etc. Could use 2 drivers per box here as well; imaging isn't critical, and they'd still be right next to each other.

It should be obvious by now that regarding this subject I'm more of an ignoramus than newbie. Need to start reading!

I use good single ended low power amplifiers.
 
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