Peerless XLS10 Subwoofer with Passive Radiator

This design uses a single 10" sub and a single passive radiator in a compact enclosure. I selected the drivers based on cost and required enclosure volume, which took me quite quickly to the well regarded Peerless 10" XLS range.

On arrival, the subwoofer packaging is less than inspiring. Off course it does its job perfectly as you would expect, but it does look budget, and there's nothing in there but the driver (no leaflet, T/S spec, plastic wrapping).

The drivers however are a nice weight and apart from minor imperfections in the aesthetics (I really am picky about these things), they are ruggedly built and look like they are ready to pound to their stated excursions.

Both the actual driver and the passive radiator are identical except that the PR has no magnet structure (hence passive). These tiny 10" drivers look, simply put, cute. Even though their enormous innertube-like surrounds give a hint that they mean business, their overall size makes them look like a cute puppy with a loud bark.

Peerless XLS 10" (830452)

I wanted to see how T/S specs change before and after being run in so I measured the driver three times: at zero hours run-in, after 30 hours run-in and after 50 hours run-in.

Here's a log of the running-in details:

Tone Power Start End Duration
Log sweep 5Hz - 20Hz 1/2 xmax 00:00 11:00 11
15Hz 3/4 xmax 11:00 19:30 8.5
25Hz 1/2 xmax 01:00 11:30 10.5
15Hz xmax 20:30 00:00 3.5
15Hz 1/2 xmax 00:00 10:30 10.5
15Hz xmax 10:30 16:30 6.0

Here's a clip of the 830452 being run-in (1.08Mb).

To measure the driver, it is fixed to my dedicated measuring clamp and the impedance plot is taken with the aid of Speaker Workshop (SW) and the Wallin Jig II.

To calculate VAS, eight 2 pence coins are stuck to the driver dustcap using blu-tac. A 2p coin weighs 7.13g, and I used a further ~7.13g of blu-tac (by using a crude balance scale and a 2p coin). So in total, 64.17g is used to calculate VAS.

The added mass method is not the best way to measure a subwoofer's VAS, but it is much quicker to implement than the sealed box method. For SW to give acceptable results with my hardware combo, I found that using a calculation bandwidth starting above 12.5 Hz is sufficient to avoid spurious impedance spikes affecting the measurements. This was enough to convince me that the added mass method will suffice for this particular sub.

The following parameters are provided:

Parameter Value Source
Re 3.4 ohms DMM
Sd 352 cm2 Peerless
Sens. 88.4 db W/M Peerless
Pe 300 W Peerless
BL 17.5 Tm Peerless
xmax 12.5 mm Peerless

The following shows the T/S parameters calculated after 0, 30 and 50 hours, and compared to the specs provided by Peerless.

Run-in Period Fs Vas Qms Qes Qts Le L1 R1
0 hours 21.2 69.52 3.90 0.22 0.21 0.82 1.06 11.8
30 hours 19.8 84.98 3.58 0.21 0.20 0.81 1.07 11.5
50 hours 18.5 89.25 3.27 0.18 0.17 0.79 1.10 12.1
Peerless 18.9 89.70 2.63 0.18 0.17 4.30
Difference * 2.0% 0.5% 19.5% 1.1% 1.7% 81.6%

* between break-in results and manufacturer specs. Note figures are rounded.

The results show that the T/S parameters after 50 hours of run-in are remarkably similar to the Peerless published specs, with the exception of Le (which is not critical for modeling enclosures).

Peerless XLS 10" Passive Radiator (830481)

Because a PR can't be measured using SW in the regular way, the Peerless specs are assumed:

Parameter Value
Fs 13.7 Hz
Qms 11.4
Vas 80 l
Rms 2 Kg/s
Mms 265g
Cms 0.508 mm/N
Sd 333 cm2
xmax 22 mm

Copyright © 2006 Vikash Chauhan. All rights reserved.