Build cabinet for Peavey 18" Low Rider Subwoofer

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If I were only using a 40 watt amp (or even 140), I would look for a woofer with even higher SPL 1W/1m. You only need about 4mm of x-max, so that will open up a lot of choices that we wouldn't normally consider for typical pro sub application. Of course this means a larger ported box.

If you were planning on upping the power (10X) later, long-ish throw drivers like the PV, or some of the mid-priced B&Cs are appropriate.
 
Thanks much for the replies. Yes I have seen many trade offs, and it seems that finding a speaker with high SPL, high Xmas, and low Fs don't seem I all come in the same package (at least not at the price point I'm looking at). Being very novice myself it's hard to know which parameters are most relevant to my goals. I'll try to think of a way to shorten my thousand questions into a brief intelligible post, here goes:

I do have a question, regarding the above models from above post. I see that the parameters for box volume and vent size are the same for all 3 models. Would those examples really be the ideal box for all three drivers? I'm assuming it's ideal for one of the drivers, and the box perameters we're not changed in order to make a clearer distinction between the three drivers.

I'm not positive that I'm even using WinISD correctly, and so I have another question. On page 3 or 4 of this PDF, http://assets.peavey.com/literature/specs/117174_13678.pdf published by Peavey, there are recommended box sizes and response curves for each. Would one of those be a good plan to follow, or are manufactures not often good at these suggestions? Also, of the 4 different boxes, which one would be the most musical with the tightest transient response? Obviously I want to go as low in frequency as possible, but not at the cost of creating a boomy one note wonder. I'm sure I'd be very happy with ~35Hz ish if that's possible.

I've been reading A LOT, and there's still a disconnect in the logic for me. So I appreciate you all helping me sort this out.
 
Obviously I want to go as low in frequency as possible, but not at the cost of creating a boomy one note wonder. I'm sure I'd be very happy with ~35Hz ish if that's possible.

That's not what happens. You get a boomy one note wonder by trying to make the box too small. "Tighter" happens by using a larger, lower tuned box which results in no low end peak and a slow roll off.
 
Okay, I had it backwards. I thought the low end peak was bad, and caused he boomieness. So I think this means larger is better for me, and I don't mind building big. Is it reasonable that I can hope that a being in a small room and if I play with speaker placement that I could gain a few dB from room resonance that would effectively give back the low end hump you refer to. ( I now assume I could equate this to "punch",... Sorry subjective words are difficult)

As a side note, another reason I like this driver, is because when I divide Fs/Qes I get 0.6 something. Being closer to .5 than 1.0,... Does this mean I could try for sealed enclosure if I don't like the sound, and am willing to add more amplifier to make it work? I'm feeling near the point of simply making sawdust; as I'm sure that will answer all my questions -it's just that it would be a waste if I'm wrong about "everything"

Alex
 
That's not what happens. You get a boomy one note wonder by trying to make the box too small. "Tighter" happens by using a larger, lower tuned box which results in no low end peak and a slow roll off.

Well, either too big or too small, can result in peaky response.

Too small, and you get a peak in the upper bass (boomy).

Too large, and you start to get a recessed upper bass, and a peak near the port resonance frequency (low bass). This can make things sound "muddy", if extreme enough.

Dan Wiggins of Adire Audio published some data, regarding vented alignments and transient response- his finding, was a slightly-smaller-than-normal box (smaller than that which would give ultimately low f3), with low port tuning (tuned low enough to get rid of any peak, in the smaller-than-normal box), can give very good transient response (i.e, perceived bass quality). To that idea, I simmed the woofer in 10 cubic feet (which, incidentally, is about exactly what you get, if you create a 2 foot by 2 foot by 3 foot external-dimension box from 3/4" wood), tuned to 27 Hz (three 4 inch diameter vents, each 10.75 inches long, per each box). Looks like only .1dB ripple, and an f3 of 28.2 Hz!

Lowering the tuning to 25 Hz (three 4" vents, 13" long each, per woofer/box), makes the group delay (transient) response even better. F3 is 29.5 Hz, with NO ripple.

Power handling is also pretty decent, due to the box not being astronomically big... though, the higher frequency port tuning will handle slightly more power than the lower frequency port tuning.

I've built enclosures with similar tuning, for various drivers- I've been happy with many of them...

Regards,
Gordon.
 
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One other point- if you build a 10 cubic foot enclosure- blocking the ports (making it a sealed enclosure) results in a Qtc of about .61. That's not bad, either. Almost a Bessel response... very good for transient response. F3 is 48 Hz, which is not bad for a sealed enclosure (many times, with 'room gain', that can work in smaller rooms well).

Regards,
Gordon.
 
THAM18 Oh Yeah bigger is always better in a cab , I will try this

I thought that with a 4 by 12 inch cab I built.
There were two problems, weight and size.
It was too heavy to lift and wouldn't fit in the car for gigs.

I now run a 2 by 12 inch full range with a 1 by 15 inch sub.
The sub fits on the passenger seat and the 2 by 12 inch goes in the back of the car.
 
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