Sub Sonic Filter for Turntable

[GOS]

Hey gang - so, I have quite a bit of trouble with playing vinyl and getting that woofer rumble at higher volumes. Yes, I have done everything known to man (except turn it down). Moved TT here and there. I have the TT pretty securely isolated, IMO. It is NOT near any speakers.

Should I try a SS filter, and how are they installed, etc. Yes, I looked online, but didn't immediately understand.

Comments are very welcome please!!

 

[fredblue]

Hey gang - so, I have quite a bit of trouble with playing vinyl and getting that woofer rumble at higher volumes. Yes, I have done everything known to man (except turn it down). Moved TT here and there. I have the TT pretty securely isolated, IMO. It is NOT near any speakers.

Should I try a SS filter, and how are they installed, etc. Yes, I looked online, but didn't immediately understand.

Comments are very welcome please!!

some preamps have it built in, maybe yours does at the flick of a switch?

 

[kap'n krunch]

I remember my Technics SL-Q2, which was a VERY STURDY TT (mfg in 1980!)...Curiously enough, my SL-QL1 from 1981 does NOT suffer the same fate. The only difference was that in my first TT i had a "cheap" (and way bigger mass than normal) Audio Technica stylus, but now I have a pretty upscale Ortofon OM30 which is also MUCH smaller...

 

[GOS]

I'm using the OM30 as well.

 

[GOS]

some preamps have it built in, maybe yours does at the flick of a switch?

No flicking for me. My Project has a built in preamp, nothing of the sort I'm afraid.

 

[DuncanS]

Sometimes the most rigid of 'structures' even with good damping lead to feedback from the speakers to the turntable, if its loud enough! I have a Rega Planar III with a Project Phono Box S2 Ultra pre-amp (connected to my SM2) which sits on top of my hi-fi rack (on wheels) which is right next to the right front floorstander. The preamp has a sub-20Hz filter, but I've never had to switch it in. What TT and pre-amp do you have?

 

[DuncanS]

No flicking for me. My Project has a built in preamp, nothing of the sort I'm afraid.

Have you rubber mounts under the TT feet?

 

[GOS]

Have you rubber mounts under the TT feet?

Yes. And underneath that, 2 layers of solid concrete blocks.......under that, another layer of rubber feet. (hockey pucks to be honest)

 

[DuncanS]

Yes. And underneath that, 2 layers of solid concrete blocks.......under that, another layer of rubber feet. (hockey pucks to be honest)

The only other thing I can think of is to try placing that thick foam rubber you sometimes get for seating (so not that squashable) directly under the TT feet. That might absorb low frequencies better. Another option is to get a TT shelf and mount on wall.

 

[GOS]

The only other thing I can think of is to try placing that thick foam rubber you sometimes get for seating (so not that squashable) directly under the TT feet. That might absorb low frequencies better. Another option is to get a TT shelf and mount on wall.

Yes, my next resort is a wall mount. To be honest, I'm not sure that will help. I'm willing to absorb $300 to try it though.

 

[aludra]

If you very carefully place your tonearm on a un-important record while the platter is still....then slowly turn up the volume to just below feedback....carefully tap around the turntable to find out where the resonances are the loudest and at what frequency....sometimes moving the turntable a few inches can reduce lowend feedback......Also if you can find a piece of granite or marble or equivalent to set your table on sometimes can help by changing the resonate feedback frequency....

It also wouldn't hurt to isolate your speakers so they transmit as little as possible thru floors/walls

Or use headphones ....just kidding..

Happy Holidays!

 

[Don C]

It's OK to use a rumble filter, I use a Radial J33 phono preamp that has one. You may be able to study the trouble a bit and see if there is something you can do with arm mass. Watch the woofers and watch the tonearm at the same time. Turn up the volume. Do you see visible motion of the woofers? Pretty common and not always bad. Is the woofer moving in time with a bass note or bass drum hit from the record? Hearing tubby, exaggerated bass? The resonant frequency of the arm and cartridge is too high. That can be corrected by adding mass at the cartridge and then re-adjusting the tracking force.
Is the woofer moving more in time with the warps or ripples on the surface of the record? Seeing lots of woofer motion but not really hearing it? Resonant frequency too low. It's harder to fix, maybe try lighter attaching hardware or a lighter headshell. Or try a different cartridge.
Or are you really hearing more of a constant rumbling sound? I'd guess a bad platter motor, maybe dried out bearings. Good luck with it.

 

[GOS]

So far, I have heard some super comments. I truly appreciate it. I will play around with it tomorrow and see what I find.

 

[par4ken]

This is not a solution unless you are an electronics hobbyist. Years ago I built a rumble filter from an article in Popular Electronics (Bass Summing Amp). That circuit simply blended the bass together below a set frequency. Switching it in and out of the circuit no difference was noticeable at all. Watching high compliance woofers moving in and with record warps/rumble you would switch it in and that movement would completely stop but all the bass remained. I don't notice any rumble problem at all with my Ariston turntable/Decca Arm, so I haven't needed to use the filter for years. Many/most modern turntables don't seem to have much in the way of suspension, sometimes just feet. The old Gerrard's and BSR's always had coil springs under them, they seemed to be less susceptible to feedback from room vibrations. I don't know if the filter would help with low frequency feedback like you are getting but it sure was the cat's ass for record warps!

 

[Bonzodog]

Ahh,

This subject brings back memories.



There was an article in Electronics Magazine (Electronics (magazine) - Wikipedia about subsonic audio and music reproduction. (late 1970’s) In it was a schematic for a steep subsonic filter. Sounded interesting to me, so I built one.



It was amazing! On some vinyl albums, turning on the filter was like removing mud from the music. On others, not so much, or not at all.



So the only thing I could deduce was that the sub-sonic problem was on the vinyl album itself, not my turntable.



Then stereo television was introduced, so I built a stereo multiplex decoder (from my design, based on a design from the same magazine). KTLA (owned by TV cowboy Gene Autry) was the first stereo TV station in Los Angeles. Some of their spots were out of phase, so I called their engineering department. They said “Impossible”. So I sent them pictures from my phase scope, (yes, I am that kind of weirdo who had a phase scope on my TV) 2 days later it was fixed.

Then our local PBS affiliate KCET went stereo. With it came wide band audio.



Not always an improvement. On network programs, everything sounded great. On local programs, I could watch my subwoofer cone bounce in and out, and sometimes the audio so muddy it was hard to understand.



Luckily my friend G.Z. was the second engineer for the station. I sent him some measurements from the station’s audio. He installed subsonic filters. The change was amazing!



Clarity improved dramatically. And the sub-woofer just sat there doing nothing on our local news shows.



So that’s my opinion of sub-sonics for music.



Get rid of it.

 

[markshan]

Yes, my next resort is a wall mount. To be honest, I'm not sure that will help. I'm willing to absorb $300 to try it though.

$300 for a wall mount? You can do it for a tenth of that. I didn't have rumble, but foot falls were a real problem for me. I bought two L brackets at Lowes and an 18" piece of butcher block at a local lumber yard and everything is right as rain now.

I can give you more details if you are interested.

 

[markshan]

One quick question, have you tried removing the dust cover? They can act like sound boards on a guitar and pick up all of the room vibration.

BTW, what kind of table is it? Some plinths can really benefit from adding putty to certain hollow spots.

 

[markshan]

It's OK to use a rumble filter, I use a Radial J33 phono preamp that has one. You may be able to study the trouble a bit and see if there is something you can do with arm mass. Watch the woofers and watch the tonearm at the same time. Turn up the volume. Do you see visible motion of the woofers? Pretty common and not always bad. Is the woofer moving in time with a bass note or bass drum hit from the record? Hearing tubby, exaggerated bass? The resonant frequency of the arm and cartridge is too high. That can be corrected by adding mass at the cartridge and then re-adjusting the tracking force.
Is the woofer moving more in time with the warps or ripples on the surface of the record? Seeing lots of woofer motion but not really hearing it? Resonant frequency too low. It's harder to fix, maybe try lighter attaching hardware or a lighter headshell. Or try a different cartridge.
Or are you really hearing more of a constant rumbling sound? I'd guess a bad platter motor, maybe dried out bearings. Good luck with it.

Great stuff. It could also be as simple as a compliance mis match between arm and cartridge. Above I asked what kind of table. I should have asked what kind of table and cart?

 

[GOS]

I’ll try to answer all these questions tomorrow am.

 

[fredblue]

No flicking for me. My Project has a built in preamp, nothing of the sort I'm afraid.

what model is your TT, GG?