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Need isolation from a nearby speaker...

drjohnnyfeva said:
I know others must have run into this problem. Seeking some potential solutions from the collective wisdom of AK.

I recently moved a speaker to create a wider field in my office. I usually listen to music from the PC, so the new configuration is better for most of my listening. However, the speaker is now on the same counter where my TT has always lived. They are separated by about 3 feet. I can't move the TT and I don't want to move the speaker back, but, when playing records, the receiver picks up a hum that grows into total distortion playing the TT at even low volume.

I need to isolate both the speaker and the TT. I have the old pitched foam pads under the speaker and the TT has the original feet with just a couple pieces of neoprene mouse pad cut to sit under them. Evidently, this is not enough given the new speaker placement. Somehow these two pieces need to live in harmony.

I don't want to spend a fortune. $150 seems steep for a isolation platform compared to $30 for some other alternative like rubber and cork or other isolation feet. Just wondering if there has been success out there that would save me the time of trial and error and returning Amazon stuff.

Thanks in advance.
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Go to a granite store and ask if they can make you a block from scrap remnants
The extra mass will change the resonant frequency of the whole system.
 
Different solutions work in different situations.
I've used: Tennis balls, squash balls, (diy) Isonoe style replacement feet and in more extreme conditions Earthquake turntable stabilizers.
And sometimes a massive slab of a heavy material below that (and in the case of the Earthquake a tile is inserted 'in' the freely moving base).

Replacement feet (or ones that you can put below) look more stylish at home, that's where i'd start.
 
drjohnnyfeva said:
Thanks for that info, @Fishead . The TT is all original, head shell and all. I've only replaced the stylus. I had it opened once when the return wasn't working and may have over tightened the springs on the table, so I'll check that too. It was super "bouncy" within the plinth, so maybe I created the problem myself. That was years ago before moving the speaker. It's Pioneer PL-115D. Not the best, but very worthy for midline tables. I'm going to look up "woofer flutter."

@dankik the TT is the Pioneer listed above and the speakers are Polks. They're about 20 years old. I don't know the model off hand.
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Pioneer turntables perform poorly with speakers 3 feet away from them. PL-115D also is not resistant to footfall, either. I know this well from experience having owned one. You likely need either extreme measures for isolation, or a turntable upgrade (neither cheap).
 
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drjohnnyfeva said:
I know others must have run into this problem. Seeking some potential solutions from the collective wisdom of AK.

I recently moved a speaker to create a wider field in my office. I usually listen to music from the PC, so the new configuration is better for most of my listening. However, the speaker is now on the same counter where my TT has always lived. They are separated by about 3 feet. I can't move the TT and I don't want to move the speaker back, but, when playing records, the receiver picks up a hum that grows into total distortion playing the TT at even low volume.

I need to isolate both the speaker and the TT. I have the old pitched foam pads under the speaker and the TT has the original feet with just a couple pieces of neoprene mouse pad cut to sit under them. Evidently, this is not enough given the new speaker placement. Somehow these two pieces need to live in harmony.

I don't want to spend a fortune. $150 seems steep for a isolation platform compared to $30 for some other alternative like rubber and cork or other isolation feet. Just wondering if there has been success out there that would save me the time of trial and error and returning Amazon stuff.

Thanks in advance.
Click to expand...
I have in the past used a piece of plate glass ( cut to fit) and some large bubble wrap underneath it. To sit the turntable on.
 
drjohnnyfeva said:
Does it more when it's closed, but when opened too. It just grows until I have to turn the receiver off.
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This is acoustic feedback. You need to decouple the turntable from the speakers. Both the physical connection (through the shelf surface) and the acoustic waves in the air.

If the speakers are facing the turntable, move the table so it is not in their direct line of sight.

I have lead-shot-filled platforms under my turntables. This helps absorb the low frequencies. I also have 2-inch-thick acrylic blocks under both. All to absorb vibrational energy. They seem to work, as the tables are ~20 to 24 inches from each speaker.

Also, good speaker cabinets should not vibrate much, even at loud volumes. You should not feel much when you place your hand on the cabinet surfaces. The audio energy should project forward from the speakers, not sideways or backward.

I have played the system over 100dBA/(meter from the speakers), no problems.


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I have two JBL L300s, two L166s, and two subwoofers (out of view of this photo).

There's a guy on eBay who makes lead-shot-filled turntable platforms.
 
Prolly recorded around 94dBA/meter.

You Sexy Thing.
Hot Chocolate. Big Tree Records. BT 89512. Monarch pressing. 1975.
Run-out: ST-BT-753459-BB (MR) AT △20155-X (2) PR
 
Took a chance on these. Not very expensive at all at $23.99. Thought they might work well with something else if they didn't work here or maybe a combination of the inner tubes or shelf. Thanks to the collective wisdom of AKers, the problem is sorted! Many thanks. Records back to normal. I was skeptical, but pleased that the first line of defense and avenue of least resistance seems to have worked. Thanks again, all. ;)


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Hey @drjohnnyfeva thanks for reporting back! I have a set of those under each subwoofer and under the 50lb slab of quartzite that my turntable sits on. Between the wall shelf and these my problems were gone as well.....nice that you didn't have to do more and got everything working as it should. It's always nice when folks follow up and tell us what worked for them so the knowledge gets passed along.....carry on amigos!
 
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