15" sub advice.

[Boscoe]

I want to build a couple new subs but can't find the drivers i want to use soo I was wondering if theres a database of drivers available and i can search it on specific parameters I want. Or alternatively if someone could suggest something? I want a 15" PA driver and would want to buy it from Blue Aran for under £150 per driver. These are the parameters I'm, after;

Fs: 25 - 30Hz
Vas: <100l
Qes: 0.3 - 0.5
Qts: 0.3 - 0.5
Qms: low as possible

So basically I want a driver basically for a vented sub 150l box target f3 of 25Hz f0 30Hz.

I don't want to use a hifi driver to ridiculous cost and almost no choice compared to PA.

Thanks
Boscoe

[Boscoe]

Found one thanks LAB-15.

[sreten]

Hi,

You want Qms as high as possible not as low as possible.

Subs are about excursion not just driver size, PA drivers in large boxes
simply require less driving power and have poor bass extension for the
box size.

No good PA bass driver I've ever seen works in a box bigger than Vas.

Driver choice in the UK is very poor and expensive, but PA drivers
don't fix that IMO, you'd might be better off IMO upping your budget
a little to Eminence LAB15's, they are £175 each for 2 to 3 from Blue Aran.
They are not typical PA drivers at all, lower sensitivity and more excursion.

Rough modelling indicates around 75L tuned to 22 to 25Hz should work well.
"classic" alignment is 65L tune to 32Hz, but IMO does not suit rooms as well.

rgds, sreten.

[chris661]

When Qes is the dominating factor, I don't see the relevance of Qms.

I've seen a lot of emphasis on Qms on here before - but I'm at a loss as to why.

[sreten]

Originally Posted by chris661

When Qes is the dominating factor, I don't see the relevance of Qms.

I've seen a lot of emphasis on Qms on here before - but I'm at a loss as to why.

Hi,

Allegedly low Qms can have effects similar to hysteresis, and AudioPhysics
used to say they wanted drivers with as high a Qms as possible, YMMV.

I've certainly seen cheap drivers where a significant part of Qts
is from low Qms, any negative issues are very hard to say.

rgds, sreten.

FWIW two Eminence LAB 12's IMO would work better domestically
than two LAB15's, somewhat bigger box sizes but go lower, but
of course not as loud. £130 each from Blue Aran, also see :
Monolith-DF

[carshateme]

To be totally honest. I'm a 10-12" fan. 15" are just too much =X.

Unless you have your mind sent on 15", check out some 10-12" subs.

[454Casull]

Originally Posted by carshateme

To be totally honest. I'm a 10-12" fan. 15" are just too much =X.

Too much for you? Or in general?

[carshateme]

Originally Posted by 454Casull

Too much for you? Or in general?

No, actually, I cannot fit 15's in my vehicle but I am told by a lot of people that 12s are better...due to something..I can't remember what.. =S

[chris661]

Originally Posted by carshateme

No, actually, I cannot fit 15's in my vehicle but I am told by a lot of people that 12s are better...due to something..I can't remember what.. =S

The usual one people quote is that the cones are much lighter, so the bass sounds "fast". This is rubbish.

A 50Hz wave can neither be fast nor slow. The thing that makes people think the bass is "fast" and "tight" is a lack of low frequency extension, usually associated with sealed cabinets.

Chris

[sharpi31]

Not specifically meeting all parameters you detailed, but I use one of these in a 150L sealed sub and get down to 20Hz no problem (small amount of eq only). Excellent value too.

Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm 295-468