[Slingshotx]

I've been more than happy with my SP1.7 for a year or so, however I recently moved some components around and I'm now finding that the sound is very sibilant and harsh and the mid range seems almost distorted on vocals and guitar.

I've checked all connections a couple of times, my first thought was I'd connected something up wrong, I've used different sources, different power amps and different speakers all with the same issue. I haven't yet put everything back to how it was before (a weekend job involving swapping stands etc !).

So my question is before I spend a weekend swapping back again does this sound like something that can happen on a pre-amp i.e. can a component fail that just affects the mid-range, am I imagining things or has swapping a few componets around and changing stands (from glass shelf to wood!) really changed the sound that much?

Any comments welcome

Slingshot

[Mag]

I suppose there can be more than one reason for sibilance. I however think it is from having a speaker that reveal too much detail in the tweeters. I noticed this when auditioning speakers by the same manufacture that the better of the two had this sibilance. It is also caused by mp3s, I notice that one of my speakers which has a very good tweeter that I can hear artifacts in the high freq.. Usually I can just ignore it, but if I concentrate on the sound I can pick it out and its quite irritating.
   I think acoustic treatments can help reduce sibilance, it focuses the sound.
Just my .02 cents.

[Slingshotx]

Thanks Mag, I agree with what you're saying it's just that in my case none of the hardware has changed, it just been repositioned and placed on a new stand.

My girlfriend has noticed it too, so it probably isn't just me. I already have some room treatments (bought and DIY) (1 bass trap has been moved in the shuffle around so another possibility).

For information the speakers are PMC OB1's TB2 centre and DB1 rears. I get the same issue if I get the sound coming from the TB2 centre or the OB1's.

Interestingly it doesn't appear that the sibilance is from the centre since if I disconnect the tweeter on the centre I still here it, so I'd guess it's maybe down in 6-7KHz range (going by definition of sibilance on wikepedia anyway).

Slingshot

My girlfriend has an interesting theory that it's because the old glass shelf's were open whereas the wooden unit is enclosed so there's a larger area for reflections etc, so I guess the only way to prove this is to replace the shelving units.

[brucek]

Have you tried in both digital and analog bypass. They don't really share much circuitry, so it might give you a clue if both sound about the same or drastically different...

[ec]

Slingshot - if it makes you feel better, I had the same problem on my SP 1.7 a while back but it only appeared to happen on the 2 ch bypass mode.  In any case, I sent the unit into Bryston for this and to get a firmware update for the processor side and when it returned - no more "hashing" problem.

[Slingshotx]

Thanks for the replies, it seemed to be the same in bypass and digital, I tried a different pre-amp and while maybe not quite as bad it still seemed to have a problem so it looks like the room changes have caused it, looks like further investigation is required.

Thanks CA I think I have the latest firmware since according to the web site I can only see the docs for 44a which gives the digital force option.

Slingshot

[James Tanner]

Hi Slingshot,

Early refections (within 5 feet) around the speaker will cause 'bright-mess' as well.

james

[chip1]

hey! slingshot

i also have a sp-1.7 although i have not experienced the sibilant that you mention, but just to let you know that bryston does have a new software upgrade which is version 44-f for the sp1.7 i installed this software my self with the bryston upgrade kit, also with a bryston technician that guided me over the phone so that i could install it properly you should inquire about it they have the best customer service department that i ever experienced.

wish all the best with your situation.

regards, chip1

[Slingshotx]

Pretty much I've improved the sound out by shifting some of the acoustic pads around and moving some furniture

Thanks Chip, anyone know what's in the upgrade, the one real problem I have is with my Xbox360, the SP1.7 doesn't seem to correctly lock on to the Digital signal correctly if it switches from DD5.1 to PCM.

I guess in the UK this would be a return to PMC for them to do it?

Slingshot

[James Tanner]

Software will not do anything for sibilance.

james

[Slingshotx]

Thanks James, I was just wondering if it would sort my issue when using an xbox360 when it switches from DD5.1 to 2ch PCM on the optical connection.

I posted about this a few months ago I get round it by setting reselecting the input mode when it happens but if it can be fixed by a firmware upgrade it would be worth it for me.

Cheers

Slingshot

[James Tanner]

Hi Slingshot - what version of software do you have now?

james

[Slingshotx]

Thanks James it states v44D1 on startup.

Cheers

Slingshot

[James Tanner]

Yes the newer software may help with that.
Contact Andy at PMC.

james

[Slingshotx]

James as you know I've been in touch with Andy@PMC, thanks for all your help, excellent service as usual.

Regards

Kevin