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Annoying Sibilance Problem

Ok so here's the scoop.

I've got a Grado Gold mounted on my Technics SL1200 and everything sounds wonderful, except on some recordings I get some pretty nasty distortion on hard T sounds and S sounds in vocals. It's not on every record but when it's there it's very apparent. I can't imagine the records are the problem as some of them are new, but I do not have another table/cart to test that right now.

The funny thing is if I swap the preamp over to mono the distortion is pretty much gone. Any ideas why it's doing this? Any help would be greatly appreciated.
silvergsx

Showing 3 responses by axelwahl

axelwahl
788 posts
 
Hells Bells, great stuff!

Doug, now you mentioned one that I actually have, and I know EXACTLY what you say.

+++ Another tough challenge in a similar way is the 'La Boheme' on Decca/London with Renata Tebaldi. On any 'La Boheme' Mimi's first big solo comes near the end of side 1, where tight inner groove modulations make the problem we're discussing more challenging. +++

I have the 'wide silver band', -- so much the better. I have made some progress in getting that 'improved' but not perfect for sure. That groove made me send a re-tipped Dorian two times back to the re-tipper. It got better, but also never really 'right'. That Tebaldi soprano could crack glasses, I say.

Thank you for your most helpful detail,
Axel
axelwahl
788 posts
 
Hi,
so let's share a bit here...

A new recording by Mobile Fidelity... pressing by Classic?: Alison Kraus & Union Station "so long so wrong" side two 'It Doesn't Matter', and even worse 'Find My Way Back To My Heart' are close to unbearably sibilant in my system.

I have tried to track this issue down, and had some expert opinion that: "sibilants are caused by frequencies out of the '[soundssssss] envelope'... (as close I can recall that statement)
I'm not a recording engineer and do not exactly get the full meaning of it, BUT it seems it has to do with a 'phasing' problem in the 3kHz - 7kHz frequency band (during recording, BUT also during playback)

Having said that, I now have checked my cartridge with the 'Ultimate Analog Test LP' by Analog Productions and an oscilloscope according to their instructions.
The result? NOT AT ALL ENCOURAGING!
Two cart parameters are out of spec. by some margin and then some: cross-talk and channel balance (I spare you the details, if interested have a look at the thread: http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1242643525 )

So, it COULD well be, that your cart has an issue, which is mostly unnoticeable, ONLY with sibilants, AND in my case orchestra tutti, and massed instruments, i.e. if things get loud and busy. The sounds then get 'smeared' by the phase-incoherence L/R as I currently understand it.

If you can, try another cart and see if it reacts differently. And oh, I assume that your arm set-up is OK, and that you have already tried various alignment-tweaks without any noticeable improvement...

Greetings,
Axel
axelwahl
788 posts
 
Hi Doug,
you say:
>>> ... there's nothing wrong with that Allison Kraus LP. <<<
Thank you for sharing that. I had a suspicion this COULD be the case. Certainly my system is not up to it (last track on side 2) in the current state.
Now it looks like I have found my 'Test-record' for this problem ---. Other than these two tracks I'd mentioned all sounds very nice otherwise.
Would you please share the other two 'tricky' LPs mentioned, it might me a good challenge to tackle those.

Hi Silvergsx,
you state:
MC - 125mV for 0.5V output from source unit
MM - 125mV for 0.5V output from source unit

That spec sounds impossible for the MC...

that 125mV looks like the overload spec. for MM and even high at that, see below.

An example could look like this:

Gain: 40 or 60dB @ 1kHz (i.e. MM or MC)

Input Overload: >100mV @ 1kHz, 40dB gain
>10mV @ 1kHz, 60DB gain

Greetings,
Axel
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