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Center channel distortion


ScottL

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I just purchased a set of Klipsch speakers (SF-1, SC-1, SS-1) and I'm having trouble with the sound quality on the center. The other speakers sound great but the center has some real harsh sounding distortion that's primarily noticable on voices. "S" and "T" sounds are especially bad, they come out sounding static-like. I thought the speaker was busted so I exchanged for another but the same problem occured. I've double checked the wiring and connections and everything looks good. Treble adjustment doesn't seem to matter either. I have also noticed that the louder the person is speaking, the less I hear distortion. I tested this in surround mode and with radio, same results. The only thing that I can think of it that my receiver is too weak (I think it's rated at something like 40W/channel). Does anyone have any other thought or suggestions?

Thanks

-Scott

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Have you calibrated the channels with a sound meter to be sure they are all set to the same relative volume? It's possible you have the center set too low/high which is causing it to be out of balance with the rest of the system and possibly distorting as you raise the volume in the system. Also, be sure the center channel is set to small in your receiver's setup menu.

DD

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scott, we've had a few discussions here where many like me too are getting the same thing on like certain movies & where somebody yells or screams.

i've come to the conclusion its in the material itself & klipsch are so revealing. i think its either microphone distortion, the mixing/sound editing quality or both.

but i'd follow doug's suggestions to get the system set-up right.

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You should try swapping the center channel speaker with one of your side speakers. This is just to see if the problem is the electronics, or with the speaker.

The power of the amp should not be a problem. You might find that there is a problem with the center channel amplifier.

Gil

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Excellent Troubleshooting advice WGM !

As a working tech ,(Computers,Printers,Networking etc.). It always pleases me to see someone who understands the basics of troubleshooting . Good troubleshooting whether in computing or audio requires the ability to analyse a problem and to determine the most appropriate

starting point for investigation,the ability to bypass utterly unlikely starting points and the ability to recognise less likely entry points and "archive" them for further investigation should the need arise

Good Troubleshooters also have the ability to rationally explore the unlikely but only after having examined the likely and less likely I don't know how you make your living but I suspect that you would make a damned good tech.

In relation to the above:

I recently got a call about a plotter that was not accepting print jobs. I determined that the plotter was OK. I further determined that it had a bad JetDirect card,( The printer equivalent of a network interface card) - VERY UNUSUAL - but not unheard of. Typically if those cards work on install they work indefinitely. In any event I replaced the JetDirect with a new one straight from the box and Voila - Same Problem ! I then tried every other possible fix/explanation and NO JOY!!

In desparation I opened up another JetDirect package and plugged the card into the plotter and while thinking longingly about a Bourbon and soda waited for this unit to also fail to hold the IP address I had set it to.

At this point folks I had exhausted all other possibilities and I knew that installing a second new JetDirect was an exercise in futility but the drilling department supervisor was alternately threatening my life or suicide - (small exaggeration here but I was under some considerable pressure) !

TADAA !! Plots began streaming from the plotter!!

I would have predicted better odds on winning the lottery than consecutive defective JetDirect cards but if you are a good tech you just don't give up without a fight !

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i've heard the same staticy sound at times also in my fronts on 5.1 movies where some of the center channel material also came out in the 2 front channels. also it was always w/ movies - music dvd or cd have always been clear as a belle. this leads me to believe its inherent in certain movie soundtracks/mixes.

for the technicals one may want to explore "compression" & "dialogue normalization" & the problem sound engineers go through w/ the various dynamic ranges, frequencies & volume levels in formatting movie sound to get optimal signal/noise ratios. or something like that. 2.gif

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Thanks for the kind words.

It will be good to hear from Scott about what happens.

BTW, Scott, is the receiver new to you too? E.g. did it work with an earlier speaker system?

- - - - - -

I recall hearing a story from long ago about New York Telephone having difficulty with their mobile radio telephone service 440 mHz transmitters. It seemed very much like the final output tubes were going bad. Opening up the sets and replacing the tube would solve the problem.

But then they found the old tubes tested good. Put the old tube back in the set and it works.

The problem was said to be dust in the tube compartment which was disturbed or cleaned out during the change.

This makes me want to ask, Lynnm whether the defective cards also failed to work in other printers. Excuse me if this is being a bit of a wisenheimer. Smile.

Gil

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" This makes me want to ask, Lynnm whether the defective cards also failed to work in other printers. Excuse me if this is being a bit of a wisenheimer. Smile."

I have no idea because after I sorted the plotter out I found that the JetDirects wouldn't fit into any other printers. HP's durability is questionable. A JetDirect should be able to withstand being stomped at least twice!!!

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Thanks for all of the quick replies to my problem. It turns out that the receiver is definitely the problem. Gils suggestion nailed it. The center sounds great when I attach it to anything BUT the center output. Unfortunately, during my monkeying around the right front output has stopped working completely. This receiver is a couple years old but I've only used it with fronts... this is my first surround sound setup. The receiver is a very low-end JVC that's turned out to be a real POS. I guess I'll be in the market for a replacement now. Thanks again for all of the suggestions!

-Scott

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Maybe the problem was that the low end HT receiver and it's amps didn't like the impedence of the speaker. I have to be careful here because I don't know the actual impedance curve of the speakers (do they dip to 4 ohms?) and I don't know how tolerant the amp is of suspected low impedance speakers.

I've had good luck driving Klipsch and home made speakers with 'classic' (read, 'old') Japanese amps. Specifically JVC and Sony. The Forte II sound very good with a new Sony mini-system. The latter came with shoe box 4 ohm speakers, which was my reason for the choice.

Maybe the receiver was challenged by the load. The center channel output distorted. Moving it to a side channel blew out the amp.

The notion that the speakers distroyed the amp is bothersome. You could blame me, blame Klipsch, or blame JVC. My recall is that we've never had such a report here. If anything, the amp protection circuit usually shuts down. Or something like this only happens with a lot of drive.

Let me suggest that when you buy a new HT receiver, you check to see whether it will drive a 4 ohm speaker.

BTW, were these speakers reviewed by Sound and Vision, or elsewhere, and was there an impedance curve? Anyone out there know?

Gil

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scott, did you ever test the center w/ dif material like a music cd? you said tuner but they're well known to have pretty low quality sound w/ mic distortion & such. still haven't ruled out the source material as the problem from what i've seen.

except now sounds like something is wrong w/ the receiver, maybe after changing things around.

gil, the sc-1 is an 8 ohm speaker & i highly doubt it gets down anywhere near 8 ohms. my guess is its much higher imped than the heresy.

you can go get a new receiver scott but don't be suprised if you still hear that staticy like distortion in some movie soundtracks. especially now that you have an ear for it. 2.gif

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Yes, I've tested the receiver with DVD, radio and CD... all produce the same distortion. I don't think I emphasized in my earlier post exactly how bad the distortion is. I'm confident that this is not how the speaker should sound. I understand that you sometimes get some static on voices with horn speakers and I sometimes catch that on my floor standing units but this is much, much worse.

Prior to purchasing the set of speakers I listened to it on a couple different receivers, all similar to what I have now, and they sounded fine. I immediately noticed the distortion when I hooked them up so I don't think it's something I developed an ear for. My fiance also noticed it right away and I don't think she could distinguish the difference in sound quality between a $200 setup and a $5000 setup.

Also, I didn't mean to imply that the speakers were causing the receiver to malfunction. It's my fiances receiver and she's moved it from apartment to apartment several times without repackaging it well so it could be something lose inside for all I know.

-Scott

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