rumble issues - see old thread update


I originally posted this under amps
as I thought I might be experiencing clipping

looks like it's definitely turntable related and rumble from subtle record warpage is the main culprit

see my last comment on this thread

http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1273520086

may check out with my outboard ZYX Artisian phono pre when I get it back from a friend

Tom
audiotomb
thanks everyone

I'll go through this thread with Richard

I do have multi weights for the triplaner and Richard and I are going to try this first- I also have the sb with the shim under the cartridge

Richard was over and said I definitely don't have an amp clipping issue - although some of the amps power is being robbed when feeding the low freq outbursts

there are some minor warped records that cleary set off pumping in the speakers, and some other's that it's so minor (but stil probably mucking up the low end) but probably still there

I want to get all the clarity out of my setup and maybe this is the limiting factor

as for suspension - I have the Silent Running Audio platforms and stand - and a very heavy platter - floor concrete - about as isolated as I can make it

it could be a room mode - I have a 14 by 27 room
long wall setup - at listening area - null against wall and reinforced 2 feet in. I've tamed slap echo with echo busters but no low freq suppression. CD's sound fine.
Table slightly forward of speaker ports which are 3' from back wall.

Perhaps if I placed the table closer to the wall on my seperate Billy Bags stand.

I'll try covering the speaker ports as well. Ports 2 2" at bottom of speaker. Jim Salk has not encountered this before with his speakers, then again, few owners with analog

Richard set this table up with a scope and the results are stunning other than the 'pumping' problem - which is there but only strong on high voumes and minutely warped records.

If this is truly a port / room issue then I'll have to look at placement of either the table or speakers. I'm a bit concerned that a subsonic filter might just mask a problem rather than correct.

Thanks

Tom
HI Tom,

I just noticed your BAT SS amp. Yeah, I doubt you're having clipping issues if that is the amp you are using. That is the worst possible problem that can occur, but it most often doesn't. Better safe that sorry though. It seems that you're woofer dance may be no different than most. Did Jim Salk think this could be detrimental to the sound of his speakers?
Tom,

If the pumping varies with volume, surely room mode interactions must be a prime suspect. My guess is that tweaking the eff. mass of the arm/cartridge may vary but will not eliminate it.

A concrete floor may dampen but it does not isolate, unless the concrete hasn't fully set and can slop around a bit. ;-) Owners of very substantial rigs on high mass stands, SRA platforms and solid concrete floors have still heard substantial improvements from adding true isolation with something like a Minus K. Not saying that would necessarily help with woofer pumping, just noting that concrete is not an isolator.
thanks guys

I'd hate to have to go to a another speaker, my friend has ported Salk's smaller

Dan_Ed - my Bat is on loan to a friend more than a few states away

Moscode 401 HR - I don't think it's clipping anymore but analog related

yes Doug volume is a culprit - increase it and more and slight warps in records.

never noticed this before, but I'm sure if things are not quite right even at lower volumes - the lower freq vail is affecting the sound.

45 rpm 180 gram blu note recordings sound fabulous
so maybe that has an effect

Room modes could be contributing. It does sound very resolving and no real flaws on cd, perhaps it sets up tone arm resonance issues. I'll try my Rives freq test and SPL if I can find them

ported speaker issue -
possibly - I'd hate to have to go to a another speaker, my friend has ported Salk's (a smaller model) and they pump all the time - he has a wood floor, not as well isolated and his speakers are close in to the back wall
sorry - floor carpet, thick pad, foundation is concrete

known as "sea meant" to the locals down here in Louisiana