Problem with surround combo (1 Viewer)

[RichardMA]

I have a Sony TA-E9000ES DD/DTS processor. I recently

added a Parasound CSE 6.1 surround "expander." THis is

essentially "Circle Surround's" processor for extracting

the matrixed centre surround channel plus 2 ceiling

channels and some other refinements not on the Circle

Surround box. Basically, the two outputs from the

Sony rear channels (L-R) are inputted to the Parasound,

which then outputs them plus the additional matrixed surround channels to my power amps.

The problem is this; When I used my Sony alone, the rear

channel residual noise level is near dead silent. Even with the volume set beyond "THX" levels, the channels

(all of them) are silent except when signals hit them.

When the Parasound is engaged(it has a bypass control)

there is a noticeable, white noise hiss that eminates from

the surround speakers. The hiss is multi-frequency, akin

to white noise. This occurs no matter which surround mode

Pro-Logic, DD, Sony proprietary modes I use. I is NOT volume dependent, either from

the Parasound volume control for the centre surround channel or from the Sony master volume control. While

this sound is not heard during surround sound signal inputs,

it is noticeable during periods when the surrounds are not

fed information. The unit's S.N. ratio is claimed 70db which is (IMO) high compared to the Sony's in any mode, but not so high that the hiss would be as noticeable as it is.

So, I was wondering if anyone else has experienced with with "add on" 6th/7th channel boxes like the Circle Surround/Parasound unit? Or, if someone knows how I might

attenuate the white noise either at line level or speaker

level?

Oh, in case anyone is wondering, the unit does indeed present "different" sound information through the centre surround speaker than either the left or right surround so it does work in that sense. I have not tried the "ceiling"

channels yet.

Thanks!

 

[Wyatt_Y]

A S/N of 70db....I would have almost guessed that to be a typo.....since most components are >100db. I have two equalizers that I have swapped between, one has a S/N of 106db, the other is 93db. I can clearly hear some hiss with the 93db unit (albeit fairly close to the speaker).

There are some variations to the S/N measurement - whether its referenced to full output or an intermediate level.... In any case, 70db is a pretty low (poor) S/N (IMHO) so it wouldn't seem surprising that you are hearing some noise.....

Wyatt

 

[RichardMA]

No, the 70db is unlikely a typo. Some old Pro-Logic

gear had this kind of noise ratio.

-Rich