Speaker Rumble With Turntable

scubalab

Calling all TT experts! I'm close to being where I want to be with my 2-channel setup. I have the following:

- Speakers - Polk Monitor 11 RTA
- Amplifier - B&K 125.2
- Pre-Amplifier - Dared SL-2000a
- Turntable - MCS 6500 (or Rega RP1 or Audio Technica AT-120)
- Phono Pre-Amplifier - Cambridge Audio Azur 651P
- Second Source - Chromecast Audio
- Speaker Cables - Zu Audio Libtec
- Interconnects - Nothing to write home about
- Power Cords - Whatever came with the component!

Currently, I'm using the MCS TT and here's the issue. It sounds pretty good, but I noticed when I took the grills off the speakers, that the drivers were going CRAZY. They were excessively moving (I'm talking like upwards of 1/2" to 1" excursion). Again, no noticeable rumble that I could hear. What was surprising was that even at relatively low volumes, with no music playing (just the needle on the record and whatever static it was projecting), the speaker drivers were dancing excessively.

I tried the same exact song, at about the same volume streamed from Spotify through the Chromecast Audio. Sounded great and the speakers were performing normally (no crazy speaker driver movement).

So, I instinctively thought subsonic rumble. I haven't tried another turntable yet, and was only able to move one speaker further away from the rack. I'll try another TT when I have some time, but I thought I'd reach out to the forum and see if anyone had some quick/easy troubleshooting tips to try in the meantime.

About a year or two ago, I had a similar issue with my daughter's 2-channel setup with her old (AT LP-60) turntable. However, with that setup, along with the excessive driver movement, there was a horrible distortion to the music, and it only reared its ugly head at moderate to higher volumes. It was obviously subsonic rumble. She has since upgraded her TT (Kenwood KD-5070) and the problem no longer exists.

Thoughts? Advice? Subsonic filter? Isolation pads for the TT?

Thanks - Al

pitdogg2

I seen the same thing on several rooms speakers using TT's. They did not seemed too worried about it.
Me personally i wondered how the speaker would of sound without all that excessive movement.

EndersShadow

Can you shoot some pics of the TT? From what I'm seeing the TT manual is not anywhere to be found so I'm wondering if there is a rumble/subsonic filter on the TT or not.

I know there is on the phono pre-amp so maybe turn that on (its called subsonic filter), and see if that changes things.



Also can you confirm which setting you are using MM/MC on the phono pre-amp.

Mikey081057

https://www.stereo.net.au/forums/topic/79277-how-to-stop-my-speakers-from-fluttering/

mhardy6647

Sounds like acoustic feedback, although it could also be a result of record warp.
It's a pretty bad thing, as it is sucking up large amounts of your amplifier's power and contributing to substantial heating of the woofers' voice coils.

Steep rolloff infrasonic filter may help -- may even cure.

Cause is physical coupling (through the air or through surfaces) but the magnitude of the problem can be exacerbated by, shall we say, unfortunate juxtaposition of tonearm mass and cartridge/stylus compliance.

mhardy6647

Testing for acoustic feedback is easy if somewhat inelegant (and sometimes kind of traumatic)

Put a rekkid on the tt (with the tt turned off, but with the amp and phono preamp on, volume to zero).
Cue down the stylus onto the rekkid.
Slowly and carefully turn up the volume.
If you have feedback issues, you'll find out.

Mikey081057

Do you play vinyl with the dustcover open or closed?

gmcman

Had the same issue when my turntable was on a glass rack right next to my right speaker. This happened with or without the dust over installed, but more pronounced with the lid open.

To remedy this, I moved the turntable but then with it being on the right wall, in direct line of the right speaker, by using a 1" thick granite table top, spiking the table, the "woofer pumping" I believe its referred to went away.

I have since moved the turntable next to my right speaker again but still on the same table with granite top, no issues.

halo

I’ve only experienced this issue with some warped records. Very unfortunate. My copy of Pink Floyd’s WYWH is warped

gmcman

Here's the thread with a vid of my 2B's when I had your same issue.

Man, hard to believe that was 6 years ago.

http://forum.polkaudio.com/discussion/130654/sda-2b-distortion#latest

scubalab

Thanks for all the responses!

Dan... well, now I feel sorta like an idiot! I'm fairly sure the phono pre is still set correctly to an MM cart, but I completely forgot it had a built-in subsonic filter. D'Oh! I think it was/is set to 'off'. So, that seems to be the easiest thing to check later tonight.

Mikey - thanks for the link... good info! Also, IIRC, the record was playing with the dustcover up/open.

Doc H - for the 'inelegant/traumatic' testing... I'll give it a shot. I'm assuming do this with the TT unplugged (since just moving the tone-arm over the record powers it up), and spin the record manually or just sit the stylus on the record while it's not spinning?

Victor - Ironically, I was spinning a Pink Floyd album as well (but it was the Wall). The record is fairly decent, but could use a good cleaning.

Gmcman - I was wondering if proximity of the speakers to the TT on the glass shelf of the rack was the issue. I can try better isolating and moving the speakers further away.

scubalab

gmcman wrote: »

Here's the thread with a vid of my 2B's when I had your same issue.

Man, hard to believe that was 6 years ago.

http://forum.polkaudio.com/discussion/130654/sda-2b-distortion#latest

That's very similar to what mine are doing. Mine seem a lot worse though... I'll see if I can get a video tonight and post it.

mhardy6647

scubalab wrote: »

...
Doc H - for the 'inelegant/traumatic' testing... I'll give it a shot. I'm assuming do this with the TT unplugged (since just moving the tone-arm over the record powers it up), and spin the record manually or just sit the stylus on the record while it's not spinning?
...

Yes, forgot that little point. It won't work if there were some sort of muting circuit that requires the tt to be energized, but I think on a component like the MCS, that's pretty unlikely. Shoulda mentioned that, sorry.

You want the stylus in contact with a record but you want the record not spinning.

You're essentially eliminating playing the record as a variable. I.e., any warp or offcenter pressing effects or drivetrain rumble are not a factor, only the physical coupling of whatever's going on in the room and the cartridge/stylus/arm/record system is being tested.

Good scientific method Well, if one controls proper controls.

EDIT: You could actually not even use a record, but just put the stylus on the platter mat... but 1) this weirds some folks out to do and it's not quite the perfect model for the test.

scubalab

The MCS does not have a muting circuit, so I'll give it a shot. My daughter's Kenwood does have a VERY nice muting feature that keeps it muted until AFTER the stylus is on the record for a second or so. It eliminates that loud pop/static when the needle makes first contact.

So, last question... spin the platter manually?

mhardy6647

scubalab wrote: »

...
Gmcman - I was wondering if proximity of the speakers to the TT on the glass shelf of the rack was the issue. I can try better isolating and moving the speakers further away.

Generally speaking, yes, distance is your friend -- but the coupling can be through the air so moving things may or may not cure the problem, although it may ameliorate the problem.

pitdogg2

pitdogg2 wrote: »

I seen the same thing on several rooms speakers using TT's. They did not seemed too worried about it.
Me personally i wondered how the speaker would of sound without all that excessive movement.

Guess I should clarify. This was at Axpona, got a little sidetracked on the phone.

scubalab

OK, I checked the Cambridge phono pre and it was set to MM (correctly) and the subsonic filter was set to “ON”. Switching it on and off doesn’t really change anything. Tonight, the flutter did not seem as bad as I remembered. I took some videos but can’t figure out how to upload using the mobile site...

gmcman

scubalab wrote: »

Gmcman - I was wondering if proximity of the speakers to the TT on the glass shelf of the rack was the issue. I can try better isolating and moving the speakers further away.

When I first had this issue, the 5-shelf Bell'O stand was directly next to the right speaker, the TT was on one of the glass shelves.

When I added the wooden stand I also found a 1" thick granite square coincidentally the same size as the table. I placed this stand along the right wall about 3' from the speaker directly in-line with the right speaker's first reflection point.

Once I found a sturdy stand, the issue stopped. Could have been the fact I moved the TT but I have since moved the rig to the long wall and the TT is back alongside my right speaker...no issues at all.

The Technics 1200 has a decent set of vibration absorbing feet which may help my case. Not the greatest but I assume they are somewhat effective.

I would try a good, solid stand and if you have a lid installed, try removing it if possible. I believe a closed lid may work better than a lid that's open when playing....experiment

motorstereo

Are your speakers spiked? I had this same problem years ago and spiking both my sub and main speakers stopped the excessive movement you mentioned earlier.

Montoya

Simple solution that usually works buy a butcher block 1”-2” thk. minimum. Buy some vibrapods place buther block on vibrapods and turntable on butcher block. You can also buy a fancy block from mapleshades.

motorhead43026

Or buy a pack of these @ $6.00. Black them out with magic marker.

https://www.amazon.com/DiversiTech-MP2-V-Anti-Vibration-Pack/dp/B01KAFG8EG/ref=sr_1_1?ie=UTF8&qid=1532608630&sr=8-1&keywords=vibration+pads+2x2

motorstereo

Another option if you need more than 4 https://www.supplyhouse.com/DiversiTech-MP-2E-EVA-Anti-Vibration-Pad-2-x-2-x-7-8?gclid=EAIaIQobChMI4tS2i-G83AIVg8DACh0AdwbyEAQYAiABEgKiLvD_BwE

mhardy6647

Those pads are 'the real deal' (as some would say).
I know folks who can afford the best imaginable -- everything -- who use 'em.

The same pads are also sold with slightly different cosmetics and under a different name as audiophile accessories for higher prices, if one has misgivings about using a high-value product.

motorhead43026

^^they really are that good, I use them under all my equipment.

scubalab

Craig - Thanks for the suggestion. I'm gonna order some!

mlistens03

I might grab some of those, as preventative work, in case I run into trouble in the future. Then I can also not have to tip toe around my room in order to keep the record from skipping.

miner

$.60/pad or $600/Stillpoint - that is an easy choice. People who push Stillpoints are ones who have deep pockets and disposable income.

EndersShadow

mhardy6647 wrote: »

Those pads are 'the real deal' (as some would say).
I know folks who can afford the best imaginable -- everything -- who use 'em.

The same pads are also sold with slightly different cosmetics and under a different name as audiophile accessories for higher prices, if one has misgivings about using a high-value product.

Hey @mhardy6647 Here is one I'm surprised YOU havent done, given your access to these....

My dad (as a organic chemist) has access to stoppers for beakers and the like.... guess who snagged quite a few over the past few years to use as isolators...


^This guy^

@scubalab while waiting for those other ones to come in, I've heard of folks using hockey pucks before as isolation..... never tried it myself, but bet you can snag some of those locally super easy.

motorstereo

miner wrote: »

$.60/pad or $600/Stillpoint - that is an easy choice. People who push Stillpoints are ones who have deep pockets and disposable income.

It would be interesting to see a non biased graph comparing stock feet to stillpoints, pads, and spikes.

mhardy6647

EndersShadow wrote: »

mhardy6647 wrote: »

Those pads are 'the real deal' (as some would say).
I know folks who can afford the best imaginable -- everything -- who use 'em.

The same pads are also sold with slightly different cosmetics and under a different name as audiophile accessories for higher prices, if one has misgivings about using a high-value product.

Hey @mhardy6647 Here is one I'm surprised YOU havent done, given your access to these....

My dad (as a organic chemist) has access to stoppers for beakers and the like.... guess who snagged quite a few over the past few years to use as isolators...


^This guy^

@scubalab while waiting for those other ones to come in, I've heard of folks using hockey pucks before as isolation..... never tried it myself, but bet you can snag some of those locally super easy.

Good point -- I haven't.
I do use hockey pucks -- mostly because I once found a box full of them on the swap pile at the ol' Harvard, MA town dump, quite a few years ago now.

miner

Hard rubber will isolate but won't dissipate energy. Rubber is well known as a problematic agent when used in a direct mechanical ground path. I replaced the inserts in my VPI Aries footer (was similar to an engine mount design - hard rubber) with the Symposium inserts. The difference is not subtle - tighter bass, better soundstage and midrange bloom.