Axiom Home Page Forums General Discussion Home Theater Clipping?

I have recently ugpraded to the world of Axiom Loudspeakers with a pair of M80's, VP150, and Qs8's, all powered with a Denon AVR-3803. I have calibrated my setup via the Rat Shack SPL and Avia at 85db with the sub +1 (SVS 20-39PC+) and I have been going through my collection of CD's, DVD's and what not.

My situation is the following, listening to various kinds of music and watching different movies I am hearing what can be described as crackling and or static during certain frequencies (not through out the entire song or movie). This 'distortion', occurs regardless of volume, ie if its loud I can hear it from my listening position, if its quiet and I move closer I can still hear it. (I should mentioned that this is primarly coming from the M80's, and as I am typing this I realize that I should probably see if any of the other speakers are doing the same, I believe the Qs8's are exhibiting the same behaviour offhand as I have caught myself looking at them during movies)

Is this what is referred to as clipping? Have I damaged my speakers with the Denon AVR-3803? Denon's specs state that the receiver can do 8ohm's@110w and 6ohm's@150w but the support page also states that they should be able to handle 4ohm speakers without any issues, nor have I had any issues with the receiver going into any kind of 'protection' mode.

I thought it was maybe the chain at first, ie the CD player and or DVD player, swapping them out with different devices, and then just sitting down with some headphones to discover that the problem didnt exist via any chain combination into the 3803 listening with headphones. Which scares me as that leaves the powered receiver and or speakers.

I would be grateful for any thoughts/ideas on the matter.

-pd

Oh yeah, I should probably also mention that with the M80's I narrowed down the 'distortion' to the tweeter's, and not the drivers (will double check again tomorrow to verify), just in case that makes any difference to anyone.

If you hear it regardless of volume level (i.e., even at lower volume levels), then it cannot be a clipping. A clipping occurs when an amplifier is overdriven and hits the ceiling of its available voltage swing. Most of the time, a clipping first occurs at the output stage of the power amp, resulting in distinct "hard" distortions at very high volume levels only. Badly "clipped" high-power signals can damage the speaker driver.

Do you hear this "distortion" in every recording you have tested?

Not every recording and or movie I listen to. It is only a handful of CD's and DVD's that I have tested from so far, and it did strike me as odd that it was occuring at all volume levels and only when it seems to hit certain frequencies. Is this just the result of the speakers just reproducing poorly mastered material to audible levels? If so, I guess I have to say wow, and doh at the same time.

-pd

see my post in the comments and questions forum... it sounds like your speaker might have a bad tweeter. if you have another speaker to compare to or some headphones especially, it would be fairly easy to tell if the recording has crackling in it. the axiom speakers are more revealing than many other speakers, but that doesnt mean theres crackling in recordings that you never noticed.

Yeah I had a similar issue with my Qs8's, and Joe convinced me to narrow it down further and I did and it was a single Qs8's bottom driver which had an offending piece of masking tape on the inside that had a corner touching the driver (which I removed and all was well). However when trying to do the same with the M80's, I swapped left for right with no difference - thus the reason I thought perhaps I damaged them with my amp somehow (unless both are bad? what are the chances, then again, with my streak...).

Tomorrow I plan on sitting down with a couple CD's that I have and see if I can narrow it down to upper or lower tweeter and pop it out and see what I can find.

-pd

Hi pdermody,

Does the 3803 have a headphone output? If so, turn off the M80s and listen there. Usually, the headphone drive is simply padded down from the stereo amp output, so if the distortion was present there, the M80s would not be at fault.

There's an outside chance that the CD/DVD player line-level output might be overdriving and overloading the preamp input section of the 3803. Although the fixed output level of CD players is supposed to be standardized at about 2 volts, some deliver a lot more, which can overload the input sections and cause distortion. If you also have a variable output on the CD player, try reducing it to see if the audio anomalies disappear.

Regards,

Hi Alan,

Yes the 3803's have a headphone out. However, I could not here the distortion via some older Koss headphones. *BUT* out of curiosity I went out and picked up some Sennheiser headphones and was able to hear the distortion I was speaking of. So that immediately ruled out the speakers (thank god for that).

So where was the noise coming from you some of you may ask? Well after swapping different devices in my chain and still hearing the distortion via the new phones I decided to pull out the SO's POS 'boombox' and pop in the disc I was testing with and yet could still hear the distortion via the headphones!

So,

1) My old Koss headphones suck
2) Speakers and Receiver are both OK
3) I revert back to my statement above of both WOW and DOH at the same time

Thanks All, guess I just needed a little reassurance. Now to see if the distortion exists on vinyl of the misc albums I was testing with.

Paul Dermody

Hi Paul,

"I decided to pull out the SO's POS 'boombox' "

Sorry, can you translate? I don't know what you are referring to. But it's all interesting, nonetheless.

Regards,

Heh, SO = Significant Other, POS being Piece Of Sh*!. Some old Boombox radio from her old college dorm days.

Paul Dermody

This story (and many other similar ones) so strikingly reminds me that so many recordings are so "bad," and so many people completely miss the defects till they get a highly capable pair of speakers like the Axioms.

Cheers