Need upgraded 15" driver for PA cab - which one...

[jakeb]

I am planning on building a 3-way pa cab similar to the qsc hpr 153i, in a non-powered format.

http://pro-audio.musiciansfriend.com...ELAID=41760020

I have the horn/mid taken care of, but I need the 15" woofer yet. The 15" used in the QSC is a celestion model at the link below

http://professional.celestion.com/pr...tail.asp?ID=17

You can buy these units at musiciansfriend, or from QSC for about 120 each, shipped.

I don't like the 2 mm Xmax. However, I do want the sensitivity of 99db. I would also prefer a 4 ohm load to maximize amplifier performance.

I can't find many 4 ohm units with similar performance. I really like the eminence 3015LF both for high sensitivity and great xmax in a smallish box, however eminence says they don't make the 4 ohm model unless I make a custom purchase of 50+ units.

So, what are my other options...bigger Xmax, 99db sens, Vas of about 5-6 cubes and 4 ohm sensitivity......? anybody.

[wg_ski]

So, what are my other options...bigger Xmax, 99db sens, Vas of about 5-6 cubes and 4 ohm sensitivity......? anybody.

You cannot change the laws of physics - or the MOQ's. Maybe consider two 12's instead of a 15.

[billfitzmaurice]

There's no benefit to going 4 ohms. The Celestion sensitivity is moot, because it only tells you what the driver is doing in the midbass, and not below 100 Hz where it counts. I can't imagine why QSC used a driver with only 2mm xmax, it's a third what I'd consider the minimum acceptable.
You should be modeling various woofers in a good box program like WinISD Alpha Pro to see what they will do in terms of low end response and maximum SPL.

[Paul O]

Yep.. amplifier power is cheap these days, so use the driver best suited to the application. If these are to be used fullrange without subs then you'll want a driver with generous excursion capability, but that will also mean larger boxes and lower sensitivity in most cases. If highest sensitivity and smallest size are the most important goals then use a more efficient driver, tune the box higher, and put subs under them.

[billfitzmaurice]

If highest sensitivity and smallest size are the most important goals then use a more efficient driver, tune the box higher, and put subs under them.

And if you're using subs don't use fifteens in the tops, that only makes them larger and heavier than tops loaded with tens or twelves that work better above 100 Hz than fifteens do.