Newby question Peerless XLS12 designs

[Glen1]

Hi Guys,
I'm after some help with box designs for a Peerless XLS12, the ...500 model. Although I've had alot of hifi gear over a long time it's all been brand names and I've decided it's time to have a go at something myself.

Peerless drivers are readily available in Australia and after doing alot of research the XLS 12 inch looks like a good choice.
I'm looking at a relatively small box of about 50 or so litres ported design.

I'm going to use a plate amp of at least 180 wrms into 8 ohms. One of my choices is a 350 watt with 6dB of bass boost at 35Hz, any opinions on bass boost for the XLS ported?

I was considering a PR system but was advised against it on extra cost alone. I want it for HT only in a room 14' x 14' x 9' ceilings for use with a HK AVR635. I did have a Velodyne SPL1200 Mk2 which I thought was very good and would like to get at least that performance expecially in the lower octaves.

I've had a go at WinISD and must admit I don't think I have either the computer or design skills to successfully design a suitable box.

I've read just about every thread and site I can on the subject and have suffered a bit of information overload.

I'm looking for some help with a design for a ported box for my project preferably with all measurements and port dimensions.
It may seem the easy way out but I'd really like to get a good result straight up with my project. Any help would be greatly appreciated.

Regards,
Glen.

[Dave Jones]

The XLS drivers are designed to be used with passive radiators. A port would have to be enormous. The XXLS line has a version designed to be used in a ported system.

[sml_nail]

If you haven't bought the sub or amp yet this is a great offer:

http://www.rzaudio.com/RZ_diyaudio_nov_offer.htm

[ashok]

Hi Glen,
This is what you are probably looking for

http://www.d-s-t.com/link/main/tech/appxls12b.htm

Cheers,
Ashok.

[paulspencer]

The XLS is a good driver, but bass boost included in most plate amps is rarely a good idea. You can remove the boost, but my prefence is to start with a power amp and add on filters. Being in Melbourne, you can easily get hold of a Jaycar subwoofer processor kit. IMO the Jaycar kit is better than the controls included in most plate amps.

I suggest have a look at the wiki
http://www.diyaudio.com/wiki/index.php?page=Loudspeaker

A lot of these questions are answered there

It's a bit tricky to design a ported box as small as 50L. The XLS will handle it but fitting in a port that won't chuff is the challenge. A guess says 60 or 70L may be required to actually get a vent that works.

Yes the original XLS was designed to go with a PR, but this does not mean that you can't make it to work in other ways. Linkwitz uses it in sealed and dipole designs - both breaking with some conventional "rules" which say that the Qts is too low for both.

[GM]

Greets!

A way around the need for using PRs and/or getting sufficient volume (Vb) while maintaining some semblance of SAF is by putting the driver in a long straight pipe, whether vented or sealed, blended into a corner or along the sound wall/floor junction. The latter is a particularly good place if the room is box shaped since it drives it in a very predictable fashion across the entire listening position without the need for tedious measurements to determine the dominant mode positions.

For example, a corner loaded 94.5" i.d. long x 9.63" i.d. square pipe with the driver mounted at floor level and a 5" dia. (or equivalent area if other than round) x 16" long vent pointed at the ceiling corner junction is ~aneochoically flat from 20 Hz to the XO point. To make it more SAF, convert it a triangular cross section of ~13.63" i.d. sides and ~19.27" i.d. across the baffle. Ideally it would go all the way to the ceiling corner, further reducing the vent's length, but the minimal extra gain isn't worth the effort IMO.

If done along the wall /floor junction, this much extra length will create a notch in the sub's passband, so the driver's position will need to be positioned ~1/4WL of the notch away from the corner.

LF BW limited high aspect ratio pipes don't need much in the way of bracing if made from at least 19 mm no -void plywood other than to support the driver, so only a few hardwood dowels randomly positioned along its length is required, but the two end caps take a pounding, so either doubling up or using marble, slate, or similar is a good plan.

Combined with its high Xmax, the XLS should have no problem peaking out around 115 dB/m/20 Hz at rated power with so-so room gain assuming the published specs are fairly close. Not enough to make DD/DTS reference, but not too shabby for a single vented 12". I'm not familiar with the Velodyne, so don't know how they compare.

WRT to amp power, any sub driver worth buying can handle at least 2x its rated power for transient bursts, so I recommend at least 600 W to ~ ensure minimal clipping. This would also up the transient peak limiting to at least 118 dB/m, putting it near/at reference if the listening position isn't in a room null.

GM