Originally Posted by climberpm
Had an outdoor party last weekend in teh backyard and was very disappointed with the output from my system. At about -15db to -10db on the Harmon Kardon volume scale my Polk (main outdoor speakers and at least 2 of my "rock" speakers, started distorting to the point that I had to turn it down to between -15 - -20db. Not nearly enough to satisfy 30 drunken dancers!
Here's my setup, hopefully someone can advise as to whether I need more or less power or what?
Harmon Kardon AVR230 Receiver, 65watts/chnl
HTD MA-1235 12 Channel Amp, 35watts/chnl
2xPolk Atrium5 speakers 100watts, using 4 bridged chnls on the HTD amp delivering 100watts each in my understanding
4xoutdoor "rock" speakers 80watts, also using 4 bridged chnls on the HTD amp via a speaker selector switch.
All speakers run through impedance matching volume controls
I also have 2 "old school" BIG JBL loudspeakers inside, connected to the speaker A output on the Harmon Kardon. They are also on a vol. control but were turned all the way down as we didn't need the music on inside. I understand having them just turned down was probably draining some of my power, I perhaps should have disconnected them completely however that was power from the receiver and not the amp which isn't really related...is it?
We have one big party a year and it seems we always want it louder but this year seemed to be the first where the disortion was this bad. Maybe I'm just getting older and more sensitive to it but it was bad. I think it's the first time I had the amp channels bridged for a party but that should have given me more volume I thought. I think Polk are ok speakers so am I overdriving them or underpowering them? For the record I can drive the big JBL speakers on their own into the +db range before I get distortion so it seems the source is clean? Is my HTD amp crap?
Thanks in advance!
Everybody blames the amps when there is distortion, when speakers have 10-100 times more distortion unless the amp is clipping badly.
I'd move the old-school JBLs to where the dancers are. You didn't say which JBLs they are, but I'm thinking something larger and more efficient.
Let's talk frankly about these Polk Atrium 5 speakers. I looked at their spec sheet and my intuition screams "BS!" Speakers this size (11 x 7 x 8) just don't have true 90 dB/W broadband sensitivity and 60 Hz (- 3dB) response.
Throwing power at speakers is a last-ditch effort. If you want loud dance music, first you get speakers with size, bass extension, and efficiency. Those three things always come together. If you sacrifice one of them, it takes the others away with it. Those are just the immutable laws of physics doing their job.
Here are some "small" speakers that I can throw a lot of power at and make work in your application:http://www.electrovoice.com/product.php?id=250
They are 18" x 11" x 10". IOW the box volume is about 8
times that of the Atrium 5s. They are rated for about the same frequency range as the Atrium 5s, and twice the efficiency. BTW, I think they don't have the claimed bass extension, but with a lot of power and a good parametric equalizer I can take care of that. By lots of power, I mean 2 kilowatts (!!!! ;-) Yes, 2000 watts). BTW, their cost seems to be in the same range at the Atrium 5s. Do you see where I'm headed here?
It is all about having the right tool for the job...