Best enclosure type for high-diameter low-XMax Driver

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So I'm looking at one of these guys:

Amazon.com: PYLE-PRO PDW21250 - 21'' Performance Optimized High Power Subwoofer: Car Electronics

And at building my own enclosure for it. Planning on using as a subwoofer in the 35-80hz range. Sounds like it will handle 500-750W RMS pretty well. Looking to get a LOT of volume out of this thing, without too much of a hit to quality.

And YES, I know it's a low-quality driver. It will not be the same as spending $500-1000. And its RMS is probably exaggerated.

Anyways, it has a rated Xmax of 9mm, a high (almost certainly exaggerated) sensitivity of 107db, and it's 21" in diameter. I'm wondering what type of enclosure will work best for this driver, given its lower Xmax but higher diameter. Or if that would have no effect on what type of enclosure to use.

Two possible uses would be both outdoors in the open, and inside of a "smallish"(can hold around 100 people) garage/shed. which types would be ideal for each, and what would be a decent compromise? I'm definitely looking more for that mid-bass punch than low-bass rumble.

Currently I'm thinking of:
1)Standard sealed enclosure (probably something around 6'x4'x2', don't remember off the top of my head) would be alright indoors, placed in a corner.
2)Ported Enclosure, probably something tuned around 30hz, looking around 5-10 cubic feet. Better for outdoors, still good inside, loss of some quality and gain of some air noise.
3)Folded Horn, (probably a rear chamber for the back end of the driver) long enough for (1/4, if I remember correctly) of a 30hz wave to get the full benefit of the horn. Faced into a corner indoors should get more volume at lower frequencies, and should still be good when faced at a small crowd outdoors. Cons of being more directional, and some issues with harmonics and distortion at some points?
4)Rear-Loaded Horn, Similar to the folded horn, no chamber over the front of the driver (duh), similar to what is being called a "scoop" but probably with a longer length for the sound to travel. Don't know much about this vs a standard folded horn.
5)Tapped Horn Heard some interesting things about these. Possible issues with distortion, phase and harmonics? Thoughts/suggestions on this one?

Any other suggestion just let me know. Also correct any errors in my thoughts :)


In recap:
Indoor suggestions
Outdoor suggestions
Compromise suggestions
Any info I missed/mad mistakes with about any of the above enclosures.


Thanks guys!
 
file:///C:/Users/cex/Downloads/PDW21250.pdf

Hi,

According to the above any use above 200Hz doesn't look promising.
It looks more like a sub than a mid bass punch driver.

Classic sealed is 7 cuft. Classic vented 13cuft tuned to 28Hz.
5 cuft sealed and 10cuft vented tuned to 30Hz are workable.

rgds, sreten.
 
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What are these "real parameters" ...

The real values of VAS, fs, and Qts. Yeah, they lie about these too - all the time. If you have those three, and reasonable estimates for Sd and Re, you can derive SPL 1M/1W. As well as determine how big the box needs to be.

Usually, the only thing "wrong" with these drivers is a relatively weak motor. You can get bass out of it if you make the box big enough - and it will be "a lot" comapred to what you're probably used to getting out of home stereo speakers. It will likely stuggle to hit 125dB at 40 Hz running full tilt, and that may take 15 cubic feet to do it. Professionals are used to getting 10dB more out of less space. That's what they get out fo their more expensive toys.
 
Hi ProbablyABadIdea,

The T/S parameters for this driver have been all over the place over the years. From the same thread that freddi linked in Post #6: http://www.diyaudio.com/forums/subwoofers/152853-pyle-21-driver-surely-cannot-11.html - djk recommends a BP4 in Post #103, and that general box type looks like a good solution. BP1Fanatic took another stab at it in Post #108. I'll attach one more Hornresp simulation, to be used w/ a 35Hz 2nd order HP. But, you'll have to measure the T/S parameters:

Measuring Loudspeaker Driver Parameters

The Subwoofer DIY Page - Measurements

Regards,
 

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Hi All,

FYI:

b:)
 

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