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Distortion on piano recordings? Advice appreciated

I'm not sure exactly where to put this, but I guess amplification is as good a place as any.

For several months now I've been occasionally noticing distortion (fuzz) in my system, only on some piano recordings. It seems to happen when they get loudest, or when the note attacks seem most intense even if not that loud. It's only at mid-high frequencies (not lows or extreme highs). Seems to be the front channels only-- I plugged my surround speakers into the front channels and heard it then too.

In that time I've changed all my components (amp, processor, CD) except the speakers, and I have tested other pairs of speakers and interconnects with the same result, though it's perhaps less obvious with RCA ICs than with XLRs.

I'm pretty sure I've also swapped out speaker cables too, though not lately. I'll try different speaker cables again this weekend, but assuming it isn't them, could it be a room node? I don't know that much about nodes, but I thought they were usually problems at much lower frequencies. Can this be this severe in the higher ranges too?

Is there anything else I'm forgetting?

System:
Halcro MC-70 Amp
Classe SSP-600 Pro
Hyperion HPS938 speakers
Aurum Cantus Leisure for surrounds
NAD M5/ Parasound players
Audioquest ICs and cables
apspr
ghostrider45
449 posts
 
The Halcro outputs over 300 watts into 4 ohms. Your speakers are rated 90 db sensitive with a 6 ohm nominal and 3.8 ohm minimum impedance. Things look pretty good on the power amp/speaker side of things.

You might be overdriving the input to your Classe processor. Your statement that "perhaps less obvious with RCA ICs than with XLRs" supports this, since the balanced connections are 6db louder than the unbalanced. I note that the NAD has a maximum output of 4.2 volts balanced while the Classe maximum input rating is 3.6 volts.

Food for thought.
ryder
1,689 posts
 
I also experience this with Fourplay's CD "Heartfelt" track no. 6. I often listen to music at moderate to high volume levels and got panicked when a few notes on the piano at a given passage got out of tune and distorted. I thought the speakers' drivers were blown or something but knew it was the recording as the defect remained when the the tune was played at low volume levels.

I would be glad if anybody who has this Fourplay "Heartfelt" CD can confirm on this. I suspect the recording engineer has screwed up on that particular part.
istanbulu
291 posts
 
.

imho you have a broken or a couple of broken speaker drivers... I'd be curious to know what you find out eventually.

As members have noted, the piano is very dynamic and demanding and the problem will only reveal itself at particular frequences and intensities.

:) listening,

Ed
shiva
181 posts
 
Another test which I have done under similar situations, is listen to the passage using my headphones only, and take the amps and speakers out of the mix. The times I did that, I still heard it and new it was the recording.
apspr OP
3 posts
 
Thanks for all the food for thought, gang.

I should have mentioned I did listen some through headphones with my previous processor (Anthem AVM-20) and got the fuzz clearly then too, so since then I have been assuming that the speakers and their cables are unlikely to be the culprits. As I mentioned, the amp has been changed (and someone noted, the Halcro has lots of power in reserve) so it never seemed like that was the issue.

To (partially) summarize your other suggestions:

1. the recordings themselves. Piano does seem to be the toughest thing to get without distortion, and the increases I've made in fidelity with upgraded gear may bring it out more. If so, then c'est la vie, I guess :)

2. a voltage mismatch/overload between the NAD (maximum output of 4.2 volts balanced) and the processors-- although the Anthem is rated at 5.3 Max input.... This is a new area to me-- Is there anything to be done about something like that, short of getting a new player?

It's not a big enough drag to kill the pleasure I'm taking in this system-- just trying to learn more about the many mysteries of audio...

Thanks again--
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