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Posted By: da-drifter Safe Audio Volume? - 09/18/11 02:06 PM
I have 4QS8's and have blown the woffers recently so I need advice on the max safe volume I should not exceed (in absolute NOT dB's.) Currently my QS8's are at -5dB and my volume is set to absolute. I like to watch my movies at about 85 absolute volume but when serious surround kicks in I'm afraid it's to much. My receiver outputs 125W/channel.
Thanks.
Posted By: J. B. Re: Safe Audio Volume? - 09/18/11 02:56 PM
those QS8 can take much more power than your receiver puts out.
first guess is you overdrove (to clipping) the amps feeding the QS8's.

if your system is well setup with no bass/treble boost, and if you listen to music or movies at realistic levels, then you should not be overdriving the amps/speakers.
when you overdrive an amp, the output power can be much more than what the specs say, but this overdriving produces distortion in the sound, and it can blow up speakers very easily.
As soon as you hear some distortion, that indicates you're overdriving the amp; you should then lower the volume enough that there is no distortion at all.
If you hear speaker bottoming, that's even worse.

What's the size of your AV room? If it's a very large room, then maybe you don't have enough power to get realistic levels without clipping the amps.

I've never used "absolute", so i can't comment on that.
Posted By: Adrian Re: Safe Audio Volume? - 09/18/11 03:24 PM
I agree with JB. It's likely your amp has been driven into clipping as the QS8s can handle considerably more power than you are giving them.
Posted By: BlueJays1 Re: Safe Audio Volume? - 09/18/11 03:33 PM
My first thought is to check your bass management setting, specifically the large/small settings on your QS8's. If you have them set to large, set them to small with a 80hz or 90hz crossover point. Having them set to large could surely stress the woofers and perhaps blow them if you are watching movies at close to reference level. You are also wasting a bit of amp power as any content sent to the surrounds below 80hz could be amplified by the subwoofer.

If it's the receiver that is clipping badly, it's the tweeters that will generally get fried.
Posted By: J. B. Re: Safe Audio Volume? - 09/19/11 11:35 AM
if you would like to know exactly when your amp is clipping, without having to guess, get amps that have LED clipping lights; for me, it's the surest way i know of.
another way is to hookup your amp output with an oscilloscope in parallel with one of the front speakers. then you can see very clearly when clipping happens.
Posted By: Argon Re: Safe Audio Volume? - 09/19/11 03:57 PM
You DO have an oscilloscope?
Posted By: J. B. Re: Safe Audio Volume? - 09/19/11 05:01 PM
i used to have one, since the 70s up to a few years ago;
it was always connected to my audio system.
this is how i discovered that my Hafler 500 amp had an instantaneous
power output on music peaks of 735 Watts/ch.; pretty good dynamic headroom. Rated continuous power was around 250W/ch/8 Ohms.

sometimes, as a show to some people, i used to connect the LF and the RF each to an oscilloscope input; that would show phasing between the 2 channels, and it made for an interesting visual rendition of the music that was playing
Posted By: da-drifter Re: Safe Audio Volume? - 09/20/11 02:55 PM
My AV room (living room) is about 25' x 18' but opens up into an office and kitchen. I think I need an amplifier but the Axiom A1400-8 is to expensive for me. Any suggestions on a cheaper amplifier? I'm thinking half the price of the A1400-8. Also, I'm not trying to make my ears bleed, just want my surrounds with more safe overhead.

I have left the surrounds at -5 dB because that is where the auto calibration set them. I have set the M80's at -12dB (the lowest channel volume) and then raised the overall volume to see if the surrounds would have more effect but the M80's still seem to over power them. Is there a way to lower the channel levels on the m80's even further?

Thanks
Posted By: SBrown Re: Safe Audio Volume? - 09/20/11 04:25 PM
Raise the QS levels until you like it! Experiment
Posted By: Brent Re: Safe Audio Volume? - 09/20/11 06:31 PM
You would be best to re-calibrate your system manually. Start from the intial set up, select small or large for the mains, small for the center and small for the surrounds. Depending on your main selection, chose the appropriate setting for your subwoofer; I would suggest using 80Hz as your default crossover point. Adjust the distance levels of each speaker to the listening position. Using the test tone, set the system manually to the listening position. Using 0db as your reference, adjust the output of each speaker so that each speaker presents the same output to the listening position. On playing a movie you may find that you might want to increase or decrease the output of your speakers to your preference.
Posted By: SirQuack Re: Safe Audio Volume? - 09/20/11 10:47 PM
da-drifter, your really confusing me. The surrounds are for "surround" affects in movies. You need to calibrate your speakers to the same levels and leave them there, don't mess with turning the 80's to -12dB to compensate for the Q's. I don't think your understanding. Either use Audyssey and trust the results, make sure to make speakers to a "small" setting after running setup. Or, use and SPL meter and run the test tones in the receiver manually, setting everything to about 75dB's.

Are you cranking up music in 7-channel stereo mode or what with the Q's. You keep mentioning getting them up to the same levels, for what?
Posted By: JohnK Re: Safe Audio Volume? - 09/21/11 02:20 AM
Drifter, despite previous discussions on this point, you still appear to have an unrealistic outlook on how loud surrounds should be. As Randy also just pointed out, you should rely on the auto-calibration done by Audyssey or others(or even a carefully done manual calibration)to have set the relative loudness between the mains and surrounds where it should be. No "tweaking" of this is necessary, and your present setting for your M80s is too low and unbalances the calibration. The mains are supposed to be prominent most of the time(this isn't "overpowering" the surrounds)and this is the result when the calibration is correct.
Posted By: da-drifter Re: Safe Audio Volume? - 09/22/11 12:01 AM
I get what your saying now, I just wasn't umderstanding how decent surround speakers sound.
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