Distortion with Rti8's (especially on vocals)

mschakowski

Hi,
I have recently purchased a new home threatre system comprising of the following components:

Onkyo 601E Receiver
Polk Rti8 Floorstanding Speakers
Polk Csi3 Fronts
Polk Rti4 Surrounds
Polk PSW404 Sub

When I listened to the speakers in the dealer's show room, I did comment on the fact that they did sound a little "harsh", especially in the high frequencies. The dealer assured me that this would pass as the speakers were run-in (apparently the demo-speakers had only been set up a few days earlier).

Anyhow, I've now owned the system for just over a month and the harshness on the front-speakers is still there, plus I have noticed an annoying hiss on vocals especially on "th" and "s" sounds. For example: "sure", would sound a little like "ssssure".

My questions:
1) Since I have probably put less than 20 hours through the speakers, should I give them more time to run in (assuming that that will cure the problem)
2) Could there be other reasons for the distortion and, if so, how can I fix it?

Thanks,

Marcus

PS. I live in South Africa, so calling customer support in the US will be a little expensive

[Deleted User]

Hello Marcus,
Thanks for posting on the Forum. I'll try and offer some useful information. Did you purchase the speakers off of display or were they new from the store's inventory? Do you notice the problem with all sources or only on a few CDs? Does the problem change if the playing volume is reduced?
Once I have some additional information I can give some opinions on what might be the cause.
Regards, Ken, Polk

mschakowski

Hi Kenneth,

Thanks for your quick response.

In answer to your questions:

1) All of the speaker's were brand-new out-the-box.

2) The problem is especially apparent with music CD's and digital satellite TV programs (which are generally broadcast in stereo and 32 kHz, 44.1 kHz or 48 kHz). DVD's are a lot better, but still a little harsh at the upper end.

3) Changing Volume does not have a significant effect on the distortion. If I turn it down and step close to the speaker, I can still hear it.

Regards,

Marcus

PolkThug

I got a dumb question for you. You don't have your treble cranked up do you? Most people around here have it set to zero. I used to have my treble turned up, til I learned otherwise.

Regards,
PolkThug

mschakowski

Hi PolkThug,

I've got the Treble turned down to -4dB (I can got as low as -12dB, but I'm not sure if that's a good idea :-)

Regards,

Marcus

F1nut

Marcus,

Welcome to the forum.

The annoying hiss on vocals that you are refering to is called sibilance. It's cause can be wide ranging from the speakers, the CD player, the receiver, the wires or a combination of all of the above. It could also be that your ears like mine are sensitive to it.

What make/model CD player are you using? What speakers did you have before? Can you try swapping the CD player and receiver with someone else? What about swapping speakers?

Jesse

mschakowski

Hi,

Thanks for your input, very much appreciated...

I'm using a Sony DVP-585 DVD player for CD playback, with a Transparent interconnect. However, the sibilance is especially noticeable when I play the Digital Satellite audio through the receiver (via cheapo RCA cables).
Unfortunately this is my first foray into the world of "serious" home cinema, so I don't have anything to compare to. Nor do I know any people with a similar setup (even a modest system like mine is rather expensive here in South Africa).

Regards,

Marcus

F1nut

Have you spoken with your dealer about this issue? Also, you have mail.

Dr. Spec

The annoying hiss on vocals that you are refering to is called sibilance. It's cause can be wide ranging from the speakers, the CD player, the receiver, the wires or a combination of all of the above. It could also be that your ears like mine are sensitive to it.

Jesse speaks the truth!

I'll throw in the source signal as another possible culprit. You say sat radio is the worst, so clearly the source affects sibilance too.

I found the combination of the Outlaw M200 and the tri-lams in the 800's to be more sibilant than any other combination I had yet tried in my system.

The tri-lam has always been regarded as a bright tweeter (with some tendency to sibilance), and the M200's are quite simply a very detailed, forward, and bright sounding amp. Combine the two and bingo - noticeable sibilance.

OTOH, the M200's and the LSi7's mate beautifully with no sibilance at all. It's all about matching the gear and the speaker.

fireshoes

You might try putting the Transparents on the satellite for a bit to see if it goes away.