How to choose 15" drivers for QSC 2450 amp?

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Total newb here (but furiously trying to learn!),

Looking to build some 2-way 15" cabinets to be powered by my QSC 2450 amp.

It's rated at 500w RMS x 2 into 8 ohms.

My biggest question is: what power rating should I be looking for in the woofer?

Is there a general rule of thumb for matching drivers to amps? I know there are a gajillion other factors, just looking for a starting point.

Wanna keep the woofers under $100 each if possible.

I will be using 1" compression drivers, and cheating with a pre-built Dayton 2-way crossover with an L-Pad tweeter gain (maybe some day I'll start building my own crossovers, but at the moment I'm clueless).

Just built my own active 10" monitor (Parts express plate amp, Eminence Alpha 10", B&C 1" compression driver), and it came out really well, so I'm pumped to build some bigger cabinets.

thanks for helping out a humble newb
 
hey there

Lunchmoney,are you talking about a 2x15+horn or just a 15+tweet?
In the case of the latter it should be pretty straight forward.
The eminance kappa or even better kappa pro looks exelent.They are however a tad over you 100 mark.
there is a eminence oem 15 with a cast basket for less on the madisound web site.Its around 70 bucks and seems to be a good deal.(check the "pro sound "pdf on their site).
I think they sell it for cheap because its not a eminence stock item.They also make suggestions about box and vent sizes but winISD could sort that out for you in a jiffy anyway.
Use a driver rated at 300-600 w.Obviously the higher rating will make it more tolerable for abuse.
Make sure it have 4 inch voicecoil,and preferably a cast frame.Do not get anything that says extended low frequency or "suitable for subwoofer" rather look for extended HF range.
15 inchers are notorious for breaking up in the upper midrange,but hey that never stopped anyone from using them with a tweeter alone.If you have the money get a larger tweeter that can be crossed lower.maybe a 1.4 or 2 inch.
If not you will still get away with decent PA sound with a regular 1 inch. If you plan on using this inside for disco rather then long throw outside,get a wide dispersion horn for the tweeter.
Making your own crossovers is easier than you might think.
The stock ones from PE are usually super generic and the components are often cheap(ie bad).But it is quick and easy.
Sort out what drivers you have in mind and Im sure we can start a new thread for you....
 
The Kappa 15LF is definitely not a good runner for combination with a 1" (it is a bass and not a midrange driver) and the non-LF has a very small Xmax. The Kappa 12 (one of the better Eminence drivers) would be better than the straight Kappa 15 in all likelyhood if you plan on running the cab fullrange.

For something cheap and simple the Speakerplans X15 works quite well for a first build (www.speakerplans.com) with the www.proaudioparts.co.uk VX-1 passive crossover which is tailored to the combination. I have a couple of measurements of the combo posted on the board.

Dunno what the P.Audio SN-15MB and BM-D450 cost in the States, but for a first project this is very efficient and can be used fullrange with a little EQ if needed. I wouldn't use a generic crossover.

For something more fullrange (and definitely old-school) check out http://www.lautsprechershop.de/pa/paudio38s.htm
 
Originally posted by lunchmoney
Looking to build some 2-way 15" cabinets to be powered by my QSC 2450 amp.

It's rated at 500w RMS x 2 into 8 ohms.

My biggest question is: what power rating should I be looking for in the woofer?

Is there a general rule of thumb for matching drivers to amps? I know there are a gajillion other factors, just looking for a starting point.


One of the least important things is power rating... for home-hifi use it is close to meaningless.

dave
 
holger honda said:
are you talking about a 2x15+horn or just a 15+tweet?

Just one 15 + tweet with a large horn lens...I've never quite understood how and why you would use two woofers and only one driver. Clearly it makes sense, I see it all the time, I just don't understand it.

These speakers would definitely not be for home stereo use, they would be my main PA system for mobile dj'ing. Right now I'm using two 12" passive Mackies (one 12 + tweet) powered by the QSC 2450, and an active 15" sub.

The setup has great low lows, mids and highs, but seems a bit weak in the mid bass...it just sounds like the main speakers want bigger drivers... so I'm considering simplifying the setup to two 15+tweet cabinets and no sub.

I did notice that the response curves for the woofer and tweeter barely overlap, so maybe stepping up to a larger tweeter would be better.

Thanks for all the help guys
 
Re: hey there

holger honda said:
Make sure it have 4 inch voicecoil...If you have the money get a larger tweeter that can be crossed lower.maybe a 1.4 or 2 inch

Any of the woofers with 4" or higher voice coil diameter are a bit out of my price range. How important is this?

And all of the compression drivers larger than 1" are WAY out of my price range.

Should I consider a 3-way? If so, what size mid driver?
 
Whaddya guys think of this driver?

SELENIUM 15PW5-SLF 15" 350W PA DRIVER

*Power handling: 350 watts RMS/700 watts max *VCdia: 3" *Le: 1.30 mH *Nominal impedance: 8 ohms *Re: 5.5 ohms *Frequency response: 40-3,000 Hz *Magnet weight: 86 oz. *Fs: 40 Hz *SPL: 97 dB 1W/1m *Vas: 6.71 cu. ft. *Qms: 16.82 *Qes: .41 *Qts: .40 *Xmax: 5.7 mm *Dimensions: Overall Diameter: 15", Cutout Diameter: 13-7/8", Mounting Depth: 5-15/16".

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=264-375
 
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