Need help with speaker problem... (1 Viewer)

[DerekF]

Something is wrong with my center channel, but I’m having a hard time reproducing and explaining it to the dealer. My question: are there any common tests anyone can recommend to highlight the problem?

Here are the symptoms of my PSB 9C:
Lots of sibilance, appearing in greater or lesser levels in all media types (TV/CD/DVD/analog/digital)
Sibilance seems worse on digital sources, but exists on all.
Using VE pink noise, I get shhhhhh from all other channels (matching PSB stuff), but from the CC I get couhhhhhhhhh

What I’ve tried:
Hooking CC to a different speaker-out on the receiver=no improvement in CC
Hooking a main to the CC-out on the receiver=perfect sound
Listening to all CC drivers=all are producing sound
Changing wire from Kimber to Monster to 12AWG zip=no change

Relevant equipment:
Yamaha RX-V2200, Kimber Kable, Panasonic A120 DVD player

My dealer already had a listen, and said “sounds alright to me”…but it sounds wrong to me, so I would like to get it fixed while still under warranty…so any thoughts, recommendations or test ideas would be appreciated!

Thanks!

 

[RussKon]

derek,

something is wrong in your amplifier section of your center channel amp. ask your dealer to have the output power tested. my guess is that your center channel amp has at least one bad power transitor...

russ

 

[DerekF]

Hi Russ!
DOH! I was hoping it wouldn't be the receiver! :frowning:
But when I hooked one of my 5Ts (mains) to the center-channel-out on my receiver, it sounded good...wouldn't it take on the same weird tonal characteristics when hooked to a bad amp? I'll give it a closer listen...(here's hoping!)...

 

[RussKon]

derek,

it is possible that the load presented to the center channel amp is different for your center channel speaker..

it's also possible that there is a loose connection/cold solder joint that is not passing all of the signal all of the time...

i'm not exactly sure of the cause of your problem, but i have a feeling that it's in your receiver...

russ

 

[Neil Joseph]

Derek, you seem to have done a fair bit of problem analysis already. Is this a matching centre for the mains? You mention all are PSB but reply with the model #'s of the PSB mains. Also, you need to always "aim" the tweeters at ear level while seating or else even matching or identical speakers will sound different from each other the more "off-axis" you are from the speaker. Just in case this does not fix, most receivers I know have EQ's where you can adjust the treble, mid, bass to each channel thereby bringing the timbre of each of the channels more into sync (this is especially useful when you have mains that do not match the centre or the surround speakers). It almost sounds as if you need to start by boosting the treble to that centre speaker for starters to get a closer timbre match to the mains (but this may be accomplished by the placement/aiming of the speakers as I mentioned). If moving the main to the CC hookup of the amp produces a good sounding main, then that in effect rules out the amp as the problem.

 

[DerekF]

Hi Neil,

My mains are PSB Image 5ts. I believe they share the midrange and tweeter with the 9C center.

The the setup is around a 32" TV that is mounted fairly high in a built-in wall unit, so the center is at the same height as the tower's tweeters.

I tried it again, and the 5T hooked up to the CC output on the receiver sounds very, very good. Clear dialogue, with very little sibilance.

I found that watching the "Inklings" on the National Geographics DVD that came with the LOTR box set is good for assessing sibilance....the dialogue is very "bright" to begin with...This same DVD sounds very different through a 5T as center as it does my 9C.

I've tried the EQ as well, but when I get rid of the sibilance, I get "boxy" sound instead...I can't find a middle ground--and it's making me crazy!