From my Mcintosh MC352 I am running speaker cables to my PD80's then jumping to the high level inputs of the built in sub amps. If, for example, the MC352 is pushing 200watts per channel, is half or that power being used to signal the sub amps? Am I wasting power just to send a signal or do the sub amps somehow filter out a line level signal? I hope this makes sense.
The A weighting measures frequencies from 500-10000Hz and the C weighting measures from 32-10000Hz. (specs from Radio Shack's spl meter)Obviously we would go with the C which came in at 120.4 db. I took the measurements with the EQ on and I do have a dip in the mids. If I were to retest with the EQ bypassed the readings would be higher. As for the Behringer reading peaks of only 99.1db, I'm stumped. It could very well be an error on my part.
Thanks everyone for your replies and that's a great hat Bignerd, did you find it while shopping for a new summer wardrobe?:)
I actually had the red peak lights flash on the MC when I did the test. Both meters were running with the peak hold activated. The MCs needles were almost stuck at the high end of the scale. If the meters on the MC are accurate I would have been pushing the 350 watt per channel envelope. I know it doesn't seem right but that's what I am reading. Maybe I am doing something wrong. You would think using pink noise would be more stable and give you a more accurate reading, but I dont really want to hear 120db of it.
My room may play a role in all of this as well, you'd have to see it. Custom built home with a WIDE open floorplan.
OK. I used my RTA mic on the behringer and a Extech digital meter. Both the mic and the Extech were placed on the back of the couch approx 14 feet from the speakers. I let the dog out put on some AC/DC and cranked it just shy of peaking out the meters on the Mcintosh. The behringer recorder a peak level of 99.1db. The Extech has an A&C weighting. I'm not sure what that means so I took measurements for both. A came in around 106db and C came in at 120.4db. Why the difference in readings? I have no clue, but it's got me wondering.
Tvad, I am serious. I do know the formula for calculating db and I have a meter. I gotta run out now and check on a job. I'll be back in an 2 hours max, take a reading or two and get back to you. My room is VERY strange I'd be glad to email you a pic as well. In fact I would appreciate any other advice you may have.
Tvad , I just wanted to clarify. I completely agree with what you are saying. I had the amp before I bought the speakers and I knew it was loads of power for the PDs. I do like the sound of the Mc and I got a great deal on it, so there it sits. I did want a system that was capable of great sound at high SPLs and the funny thing is, since I got it I normally always listen at very low levels.
Usually when listening the meters hover around 0.35 watts, but every once in a while the headbanger in me comes out and I need a quick fix.
Just to answer your basic question: If, for example, the MC352 is pushing 200watts per channel, is half or that power being used to signal the sub amps? Am I wasting power just to send a signal or do the sub amps somehow filter out a line level signal? Answer: No. The sub ams are not drawing any current from your McIntosh, they only take in the "info" from it (i.e, high level signal) and then amplify it to the woffers.
The PD80s are rated at 101db/1w/1m and 4 ohms. That means you need only 1 watt to produce 101db at 1 meter (104 db at 2 watts, 107 db at 4 watts, and 110 db at 8 watts, etc...). Do you ever listen this loud?
Rarely but yes. When I'm in the mood I'll run a couple hundred WPC.
Tvad, with all due respect the PD80s are rated from 1-600 watts per channel, I run 350. I could be wrong but it seemed wrong to run a low powered amp when each speaker houses a 1000 watt sub amp pushing 2-15s.
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