Box size correct??

[erikpeterson]

Guys: I have a Peerless sub # 830500 but am struggling with the 0.6 cu ft vented volume enclosure size shown in PE Speakers Building Guide when the similar Dayton 12" shows a volume of 2.7 cu ft vented. I tried using PE box 1.1 free download but the Peerless is not in the database. Anyone with BassBox Pro can tell me if 0.6 cu ft shown is correct vented volume? Also what is port diameter and length recommended for 0.6 enclosure??---Erik

[killerkowalczyk]

0.6 cuft is to small for sure. Im no pro but ive noticed that for a driver to perform properly in a vented enclosure the enclosure size should be about 75% of the secified VAS. Anything smaller than that and it starts to perform worse and worse. Therefore in your case a volume of 3.5cuft would probably be good. however you may want to listen to other peoples advise on this situation aswell.

[madrok]

0.6 ft3 is fine. You could make it bigger, 0.75ft3-1.2ft3. It's hard to fit a wide vent into a smaller box.

I don't know which Dayton you mean. The appropriate box size depends on the woofer parameters, and what type of response you want. The reason for the small box for the Peerless is the low Q. ALso, it has a low Fs, so you don't need to extend that by increasing box size. The small box has an unastounding F3 of 48Hz. Not very good. It would be awesome in a car though.

Do yourself a favor, forget the Boxpro crap and and write this down. It's a simple equation that determines a decent vented box size:

Vb = QTS^2.87 * 15 * Vas.

So, the bigger the Vas, and the bigger the Qts, the bigger the box.

[killerkowalczyk]

Is the fomula

vb=QTS^2.87*15*vas

or is it vb=QTS^(2.87*15*vas) ???

[madrok]

> vb= QTS^2.87 * 15 * vas

Yes.

> or is it vb=QTS^(2.87*15*vas) ???

No. That will give a tiny number!

[Chris Roemer]

> Yes.

> No. That will give a tiny number!

WinISD (free at <A HREF="http://www.linearteam.org">www.linearteam.org</A>) agrees with your small box, but see how you'd like about 1.3 cf with a 3" dia x 13.75" long port. I'd highly recommend rounding over the inside of both ends of the port.

AFAIK Dayton doesn't have ANY woofers similar to this Peerless, in that your Peerless has a very low Qts (0.20) and in most cases you'll find that Dayton's are in the range of 0.30 to 0.42 which makes them work sealed, but also seem to be optimum for ported boxes. The lower the Qts (below 0.40) the smaller the box gets, and the higher the F3 rises (compared to a driver's Fs).

Chris