Peerless Dual PR 12" XLS Sub

[HTRookie]

Hello,

I would be very grateful for some input on my peerless dual pr/12" XLS sub project. I have modelled it in Unibox, and have attached a graph showing the sub with 200 watts, 790 gram mass on the each pr, 50 litre enclosure. My questions are:

1). What is a prudent or "optimum" tuning compromise between low end response, and power handling?

2). How much of a concern is the fact that the maximum cone excursion may be exceeded at the chosen power level?

The sub will be used in a medium size room, home theatre only-and I do not listen at ear bleed volume levels..

Thanks for your help :>)

[HTRookie]

Any chance someone can please help me out a little here ? :<(

[sreten]

Originally posted by HTRookie
Hello,

I would be very grateful for some input on my peerless dual pr/12" XLS sub project. I have modelled it in Unibox, and have attached a graph showing the sub with 200 watts, 790 gram mass on the each pr, 50 litre enclosure. My questions are:

1). What is a prudent or "optimum" tuning compromise between low end response, and power handling?

2). How much of a concern is the fact that the maximum cone excursion may be exceeded at the chosen power level?

The sub will be used in a medium size room, home theatre only-and I do not listen at ear bleed volume levels..

Thanks for your help :>)

Hi,

Nothing looks wrong with your modelling, though its
more like a music subwoofer than a ht thumpbox.

The excursion is not exceeded except at very low frequencies so
I wouldn't worry, probably could take more power in typical use.

With lots more power you'd probably need to filter very low bass
and increase the tuning frequency of the PR's to reduce cone
excursion higher up in frequency and give more max SPL.

Basically the less maximum volume you need and the less maximum
power you feed in the lower you can tune the the PRs and the less
you will need to filter very low bass, same with reflexed subwoofers.

Maximum thump at 50Hz your design is not .......

/sreten.

[HTRookie]

Thanks for the feedback sreten-you are the only one that replied.

If I am missing the boat with the tuning for an HT subwoofer, could you point me in the right direction? What response curve should I strive for? It is simple enough to move the mass on the pr's around, along with the box volume in Unibox, but I dddo not know what is a good combination...

Thanks again.

[geoffs]

I am intending to make a similar subwoofer using the dimensions from the peerless site http://www.tymphany.com/papers/appxls12b.htm
The application notes use a 35 litre cabinet which is the same as the Thunder cabinet used by North Creek.
The amp I was going to use is the jaycar AA0508 which is readily available here. Have you heard of this amp being used for this speaker? How's your project going?

Cheers

Geoff

[badman]

HTRookie:

I'd leave your tuning alone- looks good, should look better with room gain. That's my style, preferring 'music' bass of very good quality to 'home theater' bass..... if there are such things. I find that once you adjust to 'tight' bass, there's no going back- 'rumble' should be a function of program content, not a proclivity of the sub.

But that's me. Either method of tuning it should provide an excellent subwoofer for most purposes. 100dB @ 20Hz is quite a bit

[infinia]

Hi
Your Unibox plot shows you have not reached the linear excursion limits with 200W. Remember total response is sum of both PR and active drive. Looking at the individual active driver only, yet shows some margin. I believe it's OK (for most subs) to go beyond Xmax peak for the drive motor, but obviously not the mechanical limit which is close to double 2*12 mm for the driver and passives.
Ideally an opt. tuning on a PR design, for freg vs excursion would be placing the active driver and passive radiator/s max excursions (12 & 24 mm resp.) at the same power level. With most designs, the PR reaches lower in freq and hits the limit first. But since you've doubled up the PR surface area you might be golden.

[HTRookie]

Thanks for the replies gentleman, I do appreciate them. As I have never had a subwoofer before-music or home theatre, I have no prior experience to know what design approach is best for either application. I don't think I want a "boom box"-but again, since this is my first sub, I'm not sure what people that want a high soudn quality HT sub build. 50 Litres is not a very big box-I can certainly accomodate more in my room. If am very open to, and would appreciate any suggestions you have to change the box volume/pr tuning to improve the SQ of this sub.

So far, I have just bought my MDF and am waiting to finalize the design. The amp was chosen on someone elses suggestion for a good quality plate amp (O Audio BASH amplifier). I am looking forward to cutting some wood this weekend- I just need confidence that my very first sub design is not a mistake :<(

Thanks,

HT