Turntable low freq. rumble

[daxhobo]

Based on my setup I cannot move my sub-woofer any further away from my turntable than it already is. I am experiencing a low freq. rumble through my sub-woofer at higher volumes due to the turntable picking up vibrations...I was wondering if there was any advice on utilizing a turntable platform like the Auralex Acoustics ISOTONE ISO-Tone Turntable Isolation Platform or if there are alternatives. The also have a sub-woofer platform similar to this...any opinions on that as well? Thank you for the help!

 

[rojo]

Based on my setup I cannot move my sub-woofer any further away from my turntable than it already is. I am experiencing a low freq. rumble through my sub-woofer at higher volumes due to the turntable picking up vibrations...I was wondering if there was any advice on utilizing a turntable platform like the Auralex Acoustics ISOTONE ISO-Tone Turntable Isolation Platform or if there are alternatives. The also have a sub-woofer platform similar to this...any opinions on that as well? Thank you for the help!

If you're looking for an isolation pad, yoga knee pads or similar would be cheaper and functionally identical. Auralex products are expensive for chunks of EVA foam. I think putting a pad under your turntable would be a good idea. Putting one under your sub might reduce your visceral experience, but could be worth experimenting for a cleaner audible experience.

Does the amp or AVR you're using offer an infrasonic filter on its phono input? If not, you could try a preamp that does (plugged into Aux rather than Phono). (I started to recommend FMODs but customer reviews claim they don't work for cutting infrasonic phono rumble.)

If your turntable and amp or sub are plugged into different electrical circuits, you could be experiencing a ground loop. If that's the case, then try creatively employing an extension cord and plugging them all into the same circuit to see whether the rumble goes away. If that's impractical for your equipment placement, then I've had some luck in the past using one of these Radio Shack ground loop isolators.

 

[daxhobo]

If you're looking for an isolation pad, yoga knee pads or similar would be cheaper and functionally identical. Auralex products are expensive for chunks of EVA foam. I think putting a pad under your turntable would be a good idea. Putting one under your sub might reduce your visceral experience, but could be worth experimenting for a cleaner audible experience.

Does the amp or AVR you're using offer an infrasonic filter on its phono input? If not, you could try a preamp that does (plugged into Aux rather than Phono). (I started to recommend FMODs but customer reviews claim they don't work for cutting infrasonic phono rumble.)

If your turntable and amp or sub are plugged into different electrical circuits, you could be experiencing a ground loop. If that's the case, then try creatively employing an extension cord and plugging them all into the same circuit to see whether the rumble goes away. If that's impractical for your equipment placement, then I've had some luck in the past using one of these Radio Shack ground loop isolators.

Thanks for the advice..I have a Parks Audio Budgie Hybrid preamp, I do not believe it has a infrasonic filter. My turntable and sub are both connected to the same electrical circuit. I will look into the pads you suggested. Thank you

 

[slipperybidness]

Thanks for the advice..I have a Parks Audio Budgie Hybrid preamp, I do not believe it has a infrasonic filter. My turntable and sub are both connected to the same electrical circuit. I will look into the pads you suggested. Thank you

Are you certain that it is sub audio that is feeding back to the stylus? Are you certain that you don't have turntable motor rumble that is getting amplified instead? If it is motor rumble, an iso-pad won't fix it, only a filter will fix it.

My sub-woofer actually has a "rumble filter" built into the amp exactly to filter out TT motor rumble.

 

[daxhobo]

Are you certain that it is sub audio that is feeding back to the stylus? Are you certain that you don't have turntable motor rumble that is getting amplified instead? If it is motor rumble, an iso-pad won't fix it, only a filter will fix it.

My sub-woofer actually has a "rumble filter" built into the amp exactly to filter out TT motor rumble.

When I pick up my TT while it is playing the rumble goes away...so I am assuming it is due to the vibration of the stand from the sub

 

[slipperybidness]

When I pick up my TT while it is playing the rumble goes away...so I am assuming it is due to the vibration of the stand from the sub

Yeah, that seems reasonable, and in this case physical/mechanical TT isolation looks like it would solve your problem.

 

[TLS Guy]

I think you have a bad turntable. What is it? With low frequency feedback between turntable and sub, it manifests itself as a continuous hum. If the volume is then advanced even a fraction the hum becomes immediately very loud and unbearable. If you are experiencing a very low pitched rumble that gradually increases as you advance the volume, it is new turntable time for you or possibly repair time depending on cause and what the turntable is.

Unfortunately with turntables, they are not like digital devices and quality increases as the price is increased usually to a highly significant degree.

 

[Ampdog]

Daxhobo,

It must firstly be determined whether the problem is hum, loudspeaker feedback or (real) rumble.

Both loudspeaker (sub-woofer) and turntable rumble can usually be fixed by an effective hi-pass filter. In fact I consider this an essential feature of good RIAA correction citcuits, whether achieved by NFB or a passive RIAA correction. (Especially the latter is often left to happily go on amplifying sub-audible frequencies after the RIAA correction, though there is very little signal on an LP below some 30Hz. If you have a commercial pre-amp it can still be built-in as part of the circuitry.

A separate unit will be more cumbersome and expensive. (D.I.Y: Such a filter is easily designed into a NFB type RIAA circuit by shaping existing component values to give a sharp cut below some 25 Hz.)

 

[sterling shoote]

A possible cause that's so obvious that it is not obvious is the subwoofer volume is turned up to high. Remember, although there can certainly be very low bass from vinyl some vinyl has no low bass at all. Attempting to get bass from such, by turning up subwoofer volume is not a remedy, instead, it just amplifies low level noise from motor, feedback, all sorts of undesirable things. My subs amp is set at half volume, and my mains are set to crossover at 60hz with sub bass management set to -8.5 db. This gets me realistic bass from albums with bass violin, guitar, and drums sounding just right. I used a Diana Krall album to get the desired setting. The setting works well. I am not getting the feeling I am listening to the sub and it works without me having to get up from my sofa to tweek the sub for every recording. i only have one LP Steely Dan's Gaucho which has noticeable rumble and its only noticeable on lead-in groove. I therefore usually keep the volume down until the performance begins, which covers the rumble pretty well.