2 Manufacturer Sugested Enclosure Sizes

[bruhthakuga]

I have a Cerwin Vega XL-12S Sub which the manufactur sugested two enclosur sizes, 2.21 cubic feet for a tuning frequency if 33 Hz which is Fs in the TS Parameters and 2.20 cubic feet for a tuning frequency of 35 Hz.

I don't have enough information to know which to choose.

The following information was emailed to me from Cerwin Vega

XL-12S Specifications

POWER HANDLING: 250 Watts RMS
SENSITIVITY: 96 db
IMPEDANCE: 4 Ohms
VOICE~COIL 2" Diameter

T5 Parameters
Fs: 33Hz
Qes: 0.261
Qms: 4.5
Qts 0.247
Vas: 4.9 Cu ft
Xmax: 0.314”
Power Handling: 250 Watts RMS

XL series subwoofers are designed for use in bass reflex enclosures
(ported).
Enclosure options:

33 Hz tuning
2.21 cubic feet (total internal volume) with round port that is 4" (diameter)
X 12.5" (length).

35 Hz tuning
2.20 cubic feet (total internal volume) with round port that is 4" (diameter)
X 10.8" (length).

[Pete Schumacher ®]

> I have a Cerwin Vega XL-12S Sub which the
> manufactur sugested two enclosur sizes, 2.21
> cubic feet for a tuning frequency if 33 Hz
> which is Fs in the TS Parameters and 2.20
> cubic feet for a tuning frequency of 35 Hz.

> I don't have enough information to know
> which to choose.

> The following information was emailed to me
> from Cerwin Vega

> XL-12S Specifications

> POWER HANDLING: 250 Watts RMS
> SENSITIVITY: 96 db
> IMPEDANCE: 4 Ohms
> VOICE~COIL 2" Diameter

> T5 Parameters
> Fs: 33Hz
> Qes: 0.261
> Qms: 4.5
> Qts 0.247
> Vas: 4.9 Cu ft
> Xmax: 0.314”
> Power Handling: 250 Watts RMS

> XL series subwoofers are designed for use in
> bass reflex enclosures
> (ported).
> Enclosure options:

> 33 Hz tuning
> 2.21 cubic feet (total internal volume) with
> round port that is 4" (diameter)
> X 12.5" (length).

> 35 Hz tuning
> 2.20 cubic feet (total internal volume) with
> round port that is 4" (diameter)
> X 10.8" (length).

Don't worry about it. Build it to 2.2 cubic feet and tune till satisfaction ensues!!!

[bruhthakuga]

Thank you very much, your response was quick. You know, I never was able to find out if I was an optimis or pest with the half empty half full glass thing for I always wanted to know how did the glass get to that volume level, did someone fill that far and stopped or was it full but had some removed.

How did you choose that volume? I want to come to an understanding so that I can choose also.

[bruhthakuga]

I also meant to include the specs to the Plate amp that I will be using, if it maters:

Specifications:
Measured power output: 180 watts RMS into 8 ohms @ .1% THD, 272 watts into 4 ohms @ 0.2% THD. Signal to noise ratio: 101dB (A-weighted). Dimensions: 10-3/8" W x 10-7/16" H x 3-1/4" D. Enclosure cut out: 9" W x 9-1/4" H. Voltage: Selectable, 115/230V, 50-60 Hz, 450W. Net weight: 12 lbs.
High power Class AB amplifier
Variable phase adjustment
Rumble Filter
Bass Boost
High pass filter for satellite speakers
Auto On/Off
Gold plated connectors

[bruhthakuga]

Sorry I got blonde for a second there 2.2 = 2.20
but still why 2.2 over 2.1?

[Pete Schumacher ®]

> Sorry I got blonde for a second there 2.2 =
> 2.20
> but still why 2.2 over 2.1?

It's such a small difference . . . you'd be hard pressed to notice it really. The best thing to do is build a little larger than you think you'll need. You can always add more braces and such to take up the volume. Then of course, there's the port, the length of which you can change to arrive at the sound you want.

Just keep in mind that there's no "perfect" vented enclosure. The variety and malleability of the box/vent/driver combo is unlimited. If you tune lower, you'll usually get better sounding music, especially for subs that reach into the 30Hz range where room effects can add to a diminishing output.

[Paul O]

I'd suggest you plug the TS specs into a modeling program first(WinISD, BasBox, etc) before the sawdust flies. That way you have an idea what to expect.

[wg_ski]

> It's such a small difference . . . you'd be
> hard pressed to notice it really. The best
> thing to do is build a little larger than
> you think you'll need. You can always add
> more braces and such to take up the volume.
> Then of course, there's the port, the length
> of which you can change to arrive at the
> sound you want.

Differences between two woofers will be as significant as the difference is those two tuning options. I'm surprised they didn't suggest two tuning options with a factor of two difference in box size (with the bigger one going deeper, of course).

[bruhthakuga]

Pete,

Thank you, that was most informative. This is my test SUBject that will end up in the car, the driver is actually made for cars but I am going to use it in the house for now. I will take the tax money to make a real set of 5.1 speakers

[Paul O]

Just be aware an enclosure design that works well at HT will be less than optimal in a car, and vise versa. So even though a driver can work well for both, the tuning requirements are very different.

[bruhthakuga]

It's all moot anyway, seconds before I got your response I found out that the subs surround that looks firm is crumbling, It is worth fixing but I am just going to order another 250 watt 12" sub for now and fix it latter for the car.

> Just be aware an enclosure design that works
> well at HT will be less than optimal in a
> car, and vise versa. So even though a driver
> can work well for both, the tuning
> requirements are very different.