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crazy speaker pulsating with turntable

Thomas_AA said:
The values may seem a bit high, but those are measured values from different sources. A mismatch cause excess movement of the arm/cartridge due to record warps in the 4-6 Hz region. You don't need a mismatch to get feedback problems, the feedback can happen at any frequency in the bass region.
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Thank you for the cu numbers on the Nagoaka, very interesting that they measure that high. I've never had this cartridge, but I know it is often recommended for arms with much higher effective mass such as the Thorens TP-16.

I've also experienced woofer pumping similar to the OP-- just having the cart on a record not even turning, I had woofer pumping just from footfalls in the room. I eventually tracked this down to a compliance mismatch, or it least it was mostly fixed by trying different cartridges.

OP, have you looked closely at the cartridge when it is playing? Take a close look at it, especially when you first set it down on the outer groove lead-in. Look to see if you can see it "wobbling" or oscillating, both the cantilever and the cart itself. Maybe even post a clip like you did for your speakers.
 
brightpav said:
Figured it was a cheaper solution to even see if it worked before investing in the KAB. Then again, if rolling off the bass on my receiver worked maybe I already have the answer of whether it works or not.
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Have you confirmed if the phono board on the receiver is functioning ok? This sounds similar to an issue I had with a Sansui integrated. Turned out it was a bad transistor on the phono board. Can you swap out some components? Different turntable or different amplification? I tried different turntable/cartridge combos and some were more sensitive to the bad transistor. My issue had nothing to do with feedback. Just a thought.
 
brightpav said:
Anyone have any insight on these? Obviously, it's a much less expensive option for filtering but I'm sure that comes with a price to the sound of course. Just curious.

https://store.acousticsounds.com/d/60042/DB_Systems-DB_Systems_Subsonic_Filter-Turntable_Accessories
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The DB Systems subsonic filter effect would be quite basic, as it only provides a 6dB roll-off per octave, and is -3dB @ 25Hz, so it’ll only be -9dB @ 12.5Hz. Whether that’s enough, I don’t know, but it’s quite similar to the IEC’s suggested modification for the RIAA curve, which was never officially taken up, but which some manufacturers have used, and which some electronics designers have used on their phono stages. The price is certainly OK, so they would be something to try, but whether they have enough low frequency roll-off to get rid of your problem, I don’t know – possibly not, since I’ve experienced feedback on phono stages which have the IEC RIAA modification (i.e. the same roll-off as the DB Systems Subsonic Filter).

So to sum up, you’d be hard-pressed to notice any difference in audio with the DB Systems filter, since most of its action occurs below the lowest audible frequency (20Hz) but it might not work that well, since it’s not a very good filter, so may not eliminate your problem. So it might be better to save your money, and try another solution.

brightpav said:
@ETI_5000 I finally did the most simplistic thing I could, which you suggested, and turned the bass all the way down on my receiver. I then jacked the volume all the way up with the needle on the groove as before and low and behold ... no speaker rumble! So I guess that's my answer eh? Some sort of subsonic feedback that will need a rumble filter to fix.

I wonder if more isolation would even matter or if I require a rumble filter?
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Probably the cheapest effective solution would be to improve the isolation of your turntable, or move it away from your speakers – the amplifier or phono preamp doesn’t need to be close to the speakers.

Better rumble or subsonic filters, with a steeper slope roll-off, or ones starting at a higher frequency of 50Hz or so with the same roll-off slope (not my choice, but quite common in many amps with ‘rumble’ filters) would also be more effective than the DB Systems filter. The IEC roll-off (and the DB Systems Subsonic Filter) should make little difference to sound, given that they start at a relatively low frequency below which little musical content exists (except for pipe organs), but the ones starting roll-off at a higher frequency will be more audible, as well as being more effective in reducing feedback and turntable rumble.

So rumble filters which have greater rates of roll-off, such as 12dB per octave or (preferably) more are the best solution, but sadly not always easy to find given the lack of info which many manufacturers release about their products.But it'll cost more to buy a rumble filter or a preamp with one, than it (usually*) does to improve isolation of your turntable.

* There are some very expensive isolation shelves, but a DIY isolation solution doesn't have to cost a lot.
 
Hifiler said:
Thank you for the cu numbers on the Nagoaka, very interesting that they measure that high. I've never had this cartridge, but I know it is often recommended for arms with much higher effective mass such as the Thorens TP-16.

I've also experienced woofer pumping similar to the OP-- just having the cart on a record not even turning, I had woofer pumping just from footfalls in the room. I eventually tracked this down to a compliance mismatch, or it least it was mostly fixed by trying different cartridges.

OP, have you looked closely at the cartridge when it is playing? Take a close look at it, especially when you first set it down on the outer groove lead-in. Look to see if you can see it "wobbling" or oscillating, both the cantilever and the cart itself. Maybe even post a clip like you did for your speakers.
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Will check. Thanks!
 
lissenup said:
Have you confirmed if the phono board on the receiver is functioning ok? This sounds similar to an issue I had with a Sansui integrated. Turned out it was a bad transistor on the phono board. Can you swap out some components? Different turntable or different amplification? I tried different turntable/cartridge combos and some were more sensitive to the bad transistor. My issue had nothing to do with feedback. Just a thought.
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I was able to confirm the issue with another receiver prior to this.
 
Other than turning the tone control, I don't think the OP has explored any of the free or cheap ideas suggested in this thread, now into a week and dozens of posts.

Most people don't have or need subsonic filters to address issues like this. Admittedly I've never really had a significant problem, or it's been so long I can't remember when, but feedback was always remediated without spending anything.
 
Two more “tests” just now:

  • Per @FONSguy suggestion I put a bath towel under the TT, put the needle down on a non-spinning record and got the speaker pulsation/feedback.
  • Turned the bass all the way down on the receiver, put the needle down on a non-spinning record and got the speaker pulsation/feedback, although I was able to turn the volume up a bit higher this time before the feedback started to occur.
I gotta believe this is the subsonic feedback etc. being picked up (and the cartridge is essentially a pickup, right?) than a vibration/isolation thing. Thoughts?

Many have mentioned how things are spaced. If I could change that up to experiment, I would but alas, this is the room I have so I gotta make it work. It’s worth noting components are not stacked nor are the speakers super close to the TT.

Thanks again for this continued chat everyone!
 
Montycat said:
Other than turning the tone control, I don't think the OP has explored any of the free or cheap ideas suggested in this thread, now into a week and dozens of posts.

Most people don't have or need subsonic filters to address issues like this. Admittedly I've never really had a significant problem, or it's been so long I can't remember when, but feedback was always remediated without spending anything.
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Hi @Montycat. I’ve tried all the suggestions made here that were functional without having to make any additional purchases. Once those are exhausted (and it seems like we’re there) I’ll look into fixes as I can afford them.

I’m sincerely grateful for all the feedback everyone has given and I’ve tried to be gracious.

If this feels like a waste of your time, that’s not my intention, but you can always unfollow the thread.
 
Not a big deal. I just sometimes see threads where we offer solutions, or potential ones, with little to no specific feedback from the the person with the problem as they cast about for that one magic formula that they think is "guaranteed" to work. However simple answers are often the best.

We also get ourselves further and further away from the real question too sometimes as we debate with each other. :)
 
Montycat said:
Not a big deal. I just sometimes see threads where we offer solutions, or potential ones, with little to no specific feedback from the the person with the problem as they cast about for that one magic formula that they think is "guaranteed" to work. However simple answers are often the best.

We also get ourselves further and further away from the real question too sometimes as we debate with each other. :)
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Got it. I know very well there ain’t no magic formula, especially when it comes to records and the anomalies that come with them!

I gotta get my hands on a new stylus for my Tracker/Goldring cartridge to see if it’s the Nagaoka that’s particularly sensitive. But my gut tells me it’s just “something in the air” suing feedback and that the rumble filter might be my next best course of action.
 
Anyway, where are you? As mentioned earlier you can get a cheap low filter in the Art Dj Pre. If you were local, I could even lend you one, but it's also only about $40 to buy.
 
A decent rumble filter does amazing things. I had a woofer pumping issue with my setup and adding a relatively inexpensive pro-ject phono box S solved it completely.

I should note that mine pumped due to warps (even tiny ones) in records and not acoustic feedback, but the rumble filter was the answer. Before everyone screams "compliance mismatch"!!, It was on a Dual 1229 with various Shure, Grado and pickering cartridges tried. Same result. The phono box also sounds better than the phono pre in my Marantz 2240. The rumble filter is at 20hz and makes no audible difference aside from the sound tightening up a tiny bit due to the woofers no longer flailing away. No reduction in bass output .
 
An update:

After emailing with Kevin at KAB and showing him my initial post here, he's confident the RF-1 can eliminate the issue.

Order placed and will report back once it's hooked up!
 
Alright one more update to those following along still:

The KAB RF-1 has arrived and all signs point to that as the solution. I have it hooked up via the tape loop so it’s switchable. When it’s engaged there is little to no speaker vibration. When it’s disengaged, the vibration is present.

Another thing of note since cartridge/tone arm compliance was brought up several times.

I swapped the Nagaoka for a Ortofon OM5E I had from a previous table. After using the tools to check compliance it appeared that it was compatible with my tone arm. That swap however doesn’t make any difference in the speaker pulsating, however it does somehow seem to be a better tracker than the Nagaoka. Too bad I can’t stand how it sounds!

Looks like you nutters were right! ;) Feedback it is!

Thank you all so much for your help. I really do appreciate it.

:beerchug:
 
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