Rumble

halo

Hello everyone!

I was listening to some records last night and I noticed that there is extreme cone excursion on the Ushers while playing records. This happens even when the needle is playing the "blank" section of the record before getting to the music section. So, even if no sound is audible, the cones on the speakers are moving quite a bit.

I have only seen rumble on this setup before when playing a warped record. Every time the needle went over the warped part of the record, there would be cone excursion on the speakers. Now, it's happening on all of my records.

The only change that I made was to further isolate the turntable from vibrations by adding a set of Isolate It!: Sorbothane Vibration Isolation Circular Disc Pad .5" (1.27cm) Thick x 2.5" (6.35cm) Dia. 50 Duro - 4 Pack to work in conjunction (stacked) on the Vibrapods I was using before. The Vibrapods did a decent job of isolating the table but if my wife stepped too heavily too close to the table, it could skip. After adding the Isolate it! on top of the vibrapods, it no longer skips but now I have rumble.

Would a different table still produce rumble or is it a case by case, table by table, kind of thing?

Is the cone excursion damaging the speakers? I haven't played anything on the table since I noticed the issue. Other than the cones movement, the sound is not altered.

Thanks for any and all input/advice/suggestions!

pitdogg2

99.99% sure it will not damage the speakers. What you have is subsonic rumble. Some phone pre's have a subsonic rumble switch to engage.( I don't know how much it helps) Several times I noticed what I thought was extreme cone movement on highly expensive speakers at Axpona yet the folks showing them didn't seem too concerned at all.

halo

Thanks Ivan.

When seeing the cone movement, I was concerned. The Bottlehead Reduction has no subsonic filter but my Art DJ II pre does. Maybe I'll connect it and see what happens.

treitz3

Hey bud, they also make inline RCA subsonic filters for this if you prefer the sound of the Bottlehead. Keep in mind, it's (to me) like adding another component into the loop and may alter the sound a bit, depending on the level and resolution of the system you want to put it in. Good thing is, they are relatively pretty cheap.

It may not hurt the speakers but if the cone is all of the way out and you have the volume up at a good clip....and then they hit a kickdrum, there is nowhere for the cone to exert too in order to produce the sound. Therefore, no sound (or very little sound) will be produced.

Tom

joecoulson

So I have a question, Ivan you said you could see this subsonic excursion on set ups at AXPONA
Where these high end tables? I can only assume they were. Am I wrong in assuming that the more expensive a table is the less chance of rumble?

halo

treitz3 wrote: »

Hey bud, they also make inline RCA subsonic filters for this if you prefer the sound of the Bottlehead. Keep in mind, it's (to me) like adding another component into the loop and may alter the sound a bit, depending on the level and resolution of the system you want to put it in. Good thing is, they are relatively pretty cheap.

It may not hurt the speakers but if the cone is all of the way out and you have the volume up at a good clip....and then they hit a kickdrum, there is nowhere for the cone to exert too in order to produce the sound. Therefore, no sound (or very little sound) will be produced.

Tom

Thanks Tom! I will look into those if the subsonic filter on the Art DJ II pre works.

halo

joecoulson wrote: »

So I have a question, Ivan you said you could see this subsonic excursion on set ups at AXPONA
Where these high end tables? I can only assume they were. Am I wrong in assuming that the more expensive a table is the less chance of rumble?

Check the Axpona 2018 thread Joe. IIRC, yes, these were high-end tables.

pitdogg2

joecoulson wrote: »

So I have a question, Ivan you said you could see this subsonic excursion on set ups at AXPONA
Where these high end tables? I can only assume they were. Am I wrong in assuming that the more expensive a table is the less chance of rumble?

Let me set one thing straight. The last time I had a table it was 1985 and by no means hi end. Yes they were pretty pricey tables. That being said i think this can be a combination of things, from recording to cartridge and so forth. Yes I agree with Tom and that was my thought with the cone movement as well.
I'm no platter guy so take my thoughts with a grain of salt.
I like the Sorbothan stuff as well Victor. I can't see it being anything more than the rumble was always there it just dissipated to the floor before and now the Sorbothan has stopped that and us feeding it back to the arm

My .02

mhardy6647

So, the kind of 'rumble' you describe is as bad as it gets in terms of potential damage to a hifi system, I would opine. The extremely low frequency and large amplitude signal that your loudspeakers are trying to reproduce is probably (almost certainly) one at which the woofers are essentially unloaded (I am assuming your loudspeakers are ported?). Worse, the amount of amplifier power being drawn is likely quite large and being turned mostly into heat in the voice coil (along with, of course, the motion you're observing).

My guess -- and it is a guess -- is that you are observing acoustic feedback and not any sort of rumble.

The traditional test for acoustic feedback (assuming one's tt allows this) is to cue the stylus down onto a record with the platter not turning. Start at zero or low volume and slowly turn up the system volume. If acoustic feedback is the culprit, at some point the cones will start to vibrate and/or a howl will become audible.

halo

mhardy6647 wrote: »

So, the kind of 'rumble' you describe is as bad as it gets in terms of potential damage to a hifi system, I would opine. The extremely low frequency and large amplitude signal that your loudspeakers are trying to reproduce is probably (almost certainly) one at which the woofers are essentially unloaded (I am assuming your loudspeakers are ported?). Worse, the amount of amplifier power being drawn is likely quite large and being turned mostly into heat in the voice coil (along with, of course, the motion you're observing).

My guess -- and it is a guess -- is that you are observing acoustic feedback and not any sort of rumble.

The traditional test for acoustic feedback (assuming one's tt allows this) is to cue the stylus down onto a record with the platter not turning. Start at zero or low volume and slowly turn up the system volume. If acoustic feedback is the culprit, at some point the cones will start to vibrate and/or a howl will become audible.

Hi Mark,

So, I can place the needle on the record if the turntable is powered off. But, if I move the tone arm over the record while it’s powered on, the platter will begin to spin. I will still get the audio from the needle touching the grove with the Bottlehead powered on.

If this is the issue, it’s come up out of the blue. What would be the fix for this?

halo

@mhardy6647

With the needle in the grove and the platter not spinning, there is no sound or movement from the cones as I gradually increased the volume level.

If the TV is on, which it isn’t when I’m listening to music, there is an increased buzzing sound coming from the speakers (my wife had the TV on before I did the test initially and I didn’t shut it off). After shutting off the TV and repeating the test, no noise of any kind and no cone movement from the speakers.

And to answer your question about my speakers, yes, they are ported.

joecoulson

Solved!

halo

joecoulson wrote: »

Solved!

How so?

joecoulson

I thought you said the TV was creating a noise that was not present when off? Did I misunderstand? Or is that another additional issue

halo

joecoulson wrote: »

I thought you said the TV was creating a noise that was not present when off? Did I misunderstand? Or is that another additional issue

The noise from the TV is a separate issue as I never have the TV on when I’m listening to music, especially vinyl. The cone excursion still takes place when I play a record but not when the needle is sitting on the record while it is stationary.

joecoulson

Ah. Sorry was thinking you isolated the issue to the TV.

So I upgraded the sub platter on my Rega and when I did it replaced the bearing (which was stainless steel) to a Ceramic one. I noticed less “rumble” although some records are worse than others. But I figured I never had a turntable at the highest level which would eliminate rumble. Or at least greatly reduce it.
One like this :

halo

I’m confused as to why I’m having this issue now since I’ve never had it in the past unless I was playing a warped record and the cone excursion was present ever time the needle passed over the warped part of the record.

joecoulson

Every record does it?

maxward

You might have eliminated acoustic feedback as a cause. I’d try to find a way to insert a subsonic filter into the phono preamp or in-line with it, as was suggested earlier. Probably worth a try.

halo

joecoulson wrote: »

Every record does it?

Yes. Every record. Even in the outer track with no recorded sound but only when the platter is in motion.

mikeyb128

Is it possible it has always done this and you only noticed it now? After you put these cones under your table did you re-level? And check all other adjustments? Main cause of woofer pumping on records that aren’t warped is cartridge arm mismatch. I know this because I’ve been there. Some amount of woofer pumping is normal. Most high end phono stages don’t have subsonic filters due to sound degradation, and from what I’ve heard they aren’t always effective.

halo

mikeyb128 wrote: »

Is it possible it has always done this and you only noticed it now? After you put these cones under your table did you re-level? And check all other adjustments? Main cause of woofer pumping on records that aren’t warped is cartridge arm mismatch. I know this because I’ve been there. Some amount of woofer pumping is normal. Most high end phono stages don’t have subsonic filters due to sound degradation, and from what I’ve heard they aren’t always effective.

Yes, everything was reset and leveled again after installing the isolate it! feet.

I have tried 5 different cartridges and they all do it so I don't think it's the cart/tonearm mismatch.

I worked backward from all changes I've ever made.

I removed the isolate it! feet and used just the Vibrapods - same issue.

I removed the Way Excellent Mat II and reinstalled the OE mat - same issue.

I swapped out my interconnect cables to the ones I was using before to see if there's any difference - same issue.

The only other variable is the Usher speakers. I wasn't listening with the grills off until recently and that's when I saw the cone excursion.

I know, for a fact, that the Polk S60 speakers and the Polk LSiM 705 speakers didn't have cone movement like this when listening to vinyl records.

@mhardy6647 - Is it possible that the Technic's direct drive motor is causing the issue?

mhardy6647

based on @halo's signature, he has a moderately low compliance cartridge and a medium-ish mass arm; should be OK in terms of system resonant frequency.

halo wrote: »

mikeyb128 wrote: »

@mhardy6647 - Is it possible that the Technic's direct drive motor is causing the issue?

Short answer, I dunno -- although I doubt it. I suppose that it could (????)be bearing related -- perhaps main bearing lubrication (although I have no idea how to lubricate the bearing in an SL-Q2).

I would argue that, although some occasional infrasonic cone movement is common in the real world playing records, it's never a good thing. Some phono preamps have infrasonic filters built in for just that reason, in fact. It's not just for aesthetics!

halo

mhardy6647 wrote: »

based on @halo's signature, he has a moderately low compliance cartridge and a medium-ish mass arm; should be OK in terms of system resonant frequency.

Thanks Mark. Any thoughts on the direct drive motor?

I did try my Grado Red & AT120eb with no difference in the cone movement.

Clipdat

halo wrote: »

Thanks Tom! I will look into those if the subsonic filter on the Art DJ II pre works.

Results of trying the different preamp w/ the subsonic filter?

halo

Clipdat wrote: »

Results of trying the different preamp w/ the subsonic filter?

The Art DJ Pre II with the subsonic filter engaged has eliminated the rumble/excessive cone movement.

Clipdat

halo

Clipdat wrote: »

lol Drew but not exactly how I'm feeling. I'd rather be using the Bottlehead phono pre vs the Art DJ Pre II.

mhardy6647

halo wrote: »

Clipdat wrote: »

lol Drew but not exactly how I'm feeling. I'd rather be using the Bottlehead phono pre vs the Art DJ Pre II.

Speaking of which -- wonder if the Bottlehead preamp might be oscillating? I don't think it's likely, but it's not impossible. Maybe swap in another set of tubes? Is it a Seduction or Reduction (i.e., two 6DJ8s)?

halo

mhardy6647 wrote: »

halo wrote: »

Clipdat wrote: »

lol Drew but not exactly how I'm feeling. I'd rather be using the Bottlehead phono pre vs the Art DJ Pre II.

Speaking of which -- wonder if the Bottlehead preamp might be oscillating? I don't think it's likely, but it's not impossible. Maybe swap in another set of tubes? Is it a Seduction or Reduction (i.e., two 6DJ8s)?

It’s a reduction with the integration upgrade. It uses two 6922 tubes.

mhardy6647

6922 = 6DJ8
If you've got another pair, try 'em. Can't hurt.