Loudspeakers AC15 Amplifier
- Thread starter0HZ
- Start date
bishopthomas
Well-Known Member
The general rule is give the speaker twice the RMS rating and you'll be more than good. We use XTI 4000's on our AC15's and AC16's, only because that's what we have. The only time we used anything different was an iTech 5000. Blew ever driver when used on an outdoor festival rock show for front fills.
Here's an excellent document about power handling and selecting amplifiers:
(PDF Warning) http://www.electrovoice.com/downloadfile.php?i=2320
(PDF Warning) http://www.electrovoice.com/downloadfile.php?i=2320
16 ohm speakers require a larger voltage swing to drive than 8 ohm speakers. Neither the XTI2002 or 4004 list a 16 ohm spec, so we're guessing about the maximum voltage they can produce. Based on extrapolating from the 8 ohm numbers and assuming that's the maximum voltage the amps can produce:
The XTI2002 can do at least 232 watts at 16 ohms stereo
The XTI4002 can do at least 324 watts at 16 ohms stereo.
Based on this, I'd rather have the 4002.
One other option for you - if you don't need stereo, you can parallel two speakers for an 8 ohm load. If you bridge even the XTI2002 into this 8 ohm load, you will have plenty of power - 1600 watts. Bridging is usually frowned upon due to extra stress on the amp, but this is usually because people are trying to suck every last watt out of the thing and run with very low impedances. In this particular case, you're bridging to take advantage of the extra voltage swing of using both channels, and an 8 ohm bridged load is equivalent to a 4 ohm stereo load, so the amp won't be working very hard.
The XTI2002 can do at least 232 watts at 16 ohms stereo
The XTI4002 can do at least 324 watts at 16 ohms stereo.
Based on this, I'd rather have the 4002.
One other option for you - if you don't need stereo, you can parallel two speakers for an 8 ohm load. If you bridge even the XTI2002 into this 8 ohm load, you will have plenty of power - 1600 watts. Bridging is usually frowned upon due to extra stress on the amp, but this is usually because people are trying to suck every last watt out of the thing and run with very low impedances. In this particular case, you're bridging to take advantage of the extra voltage swing of using both channels, and an 8 ohm bridged load is equivalent to a 4 ohm stereo load, so the amp won't be working very hard.
TJ touched on a critical factor which is the application. Do you need to get everything you can from the speakers? Do you have just two speakers and are you only running one speaker per channel? Who is running the system and can you assume they will not try to push it too hard? Is there a reason you are looking specifically at the XTi amps?
FWIW, the difference between 232 Watts per channel and 324 Watts per channel is 1.45dB so very few people would be able to hear the difference. So unless you really need to get every last bit out of the speakers or want that extra little bit of headroom before someone would be into clipping then that might make it difficult to justify any additional investment.
bishopthomas
Well-Known Member
bishopthomas
Well-Known Member
Never had any problems getting enough volume out of them. But we're not trying to use them in situations where they would not be adequate. Our primary use is balcony/front fills, background music in tents, etc. As I mentioned, the only problem we ever had was actually from OVER powering them during an outdoor festival.
Any amp that isn't garbage will produce good sound quality within it's linear range - i.e. up to the point of clipping. This is no sound quality penalty for an amp that is "too small", assuming you are happy with the volume that can be produced without the amp being driven into clipping.
The larger XTI will sound the same as the smaller one within its limits.
As Brad pointed out, it takes a large difference in available power to make a comparatively small difference in output, so don't sweat this too much.
Similar threads
