TT & subs = Rumble/woofer pumping?

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Gordon

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On a whim this weekend, I purchased my first TT in 30 years. It is a Pro Ject 1-Xpression III with an Ortofon 2m Red cart. I gave $400 for the kit. IF this small experiment pans out, a higher level table is in the cards. I did not want to invest more funds until I figured out some of the ins and outs of spinning vinyl.

The first major issue I'm experiencing is woofer pumping. At low volume level, up to about 40 on my pre, the sound is fine. Once I exceed 40, both subs are going into convulsions! There is a physical and audible fast pumping which forces me lower the volume. If I turn the subs off, the pumping disappears and I am not volume limited.

The table is on my rack, top shelf centered between the speakers/subs. There is about 4.5ft from table to each sub. The front plane of the subs is about 6 inches in front of the table. I'm using some AudioQuest Viper ICs I had on hand and the TT is grounded to the pre. The ground has no impact on the pumping as I've tried both configurations.

Searching the web has given me a few ideas.
1. Isolate the table. Wall mount and or sand box
2. Use of a rumble filter. KAB RF-1 is the most noted
3. Move table.

I understand the first two. But what I could not nail down is how long of an IC can be used between TT and pre?

If any of you guys can give me some other suggestions, I'm all ears!
 
Searching the web has given me a few ideas.
1. Isolate the table. Wall mount and or sand box
2. Use of a rumble filter. KAB RF-1 is the most noted
3. Move table.

I understand the first two. But what I could not nail down is how long of an IC can be used between TT and pre?

If any of you guys can give me some other suggestions, I'm all ears!
Keep the I/C as short as you possibly can. Do not exceed 2m (1m is preferable).

A lot of guys here use subs only for HT. You should listen for a while to determine if you really need the subs for 2-channel.

Using a rumble filter and subs sounds counter-productive. I think your best bet would be to try the wall mount first; I'm assuming you have a sprung wooden floor.
 
how long of an IC can be used between TT and pre?

Gordon, sounds as if your subs are creating quite a 'rumble' and driving your cartridge into an orgasim !

tt to phono-pre IC length should be kept to a minimum, IMO. Limiting factors (because of such low voltage) are RFI, EMI, which is to say it depends on your enviroment.

As a general rule (that I follow) the lower the voltage / signal that passes through the cable the shorter that length of cable should be, so my shortest is TT to phono-pre, phono-pre to pre-amp, pre-amp to amp(s) in that order.
 
I think there is some debate whether or not there is any encoded information in a record which a subwoofer is supposed to reproduce.

I use a subwoofer for HT only.

However on my old set up for 2-channel the sub seemed to slow down the music and destroyed the stereo signal by splitting it (via piggy back wires). The sub sometimes picked up my footsteps, and you could forget about tapping on the turntable base - it would go crazy.

Maybe if you isolated the table better or spent + $10,000 on a turntable you could have rumble free subwoofer use.
 
I never had a problem with my Thorens 126. I guess it has such a good suspension that it is essentially acoustic feedback free. I would say it´s the feedback from the subs causing the trouble. You can check by using headphones and play it loud headphones only. If you hear the same problem then it is rumble, otherwise feedback.
If it is feedback you can try putting the turntable on a surface (I would use marble) with some suspension beneath - I had good success with tennis balls for example. Might be cheap enough to give it a try. Then you could look for a more decent looking solutions.
 
Maybe if you isolated the table better .

hey Len I think george is trying to scare you as Bernard says....:eek:

Isolation is a BIG key in your case.

FWIW, I utilize my sub in my set-up 100% of the time, no problem-o........why not, you payed for the damn thing !
 
Bingo Dave! I have the subs well integrated and want to use them. Looks like I'll have to dig deeper into the isolation aspect.

This is why I bought an inexpensive table to start!

Gordon
 
Gordon, I totally agree. Don't use subs with your new TT .

You know those 2 fantastic new Fathom subs you just finished integrating into your system? You should probably send them to one of us that has no vinyl set up for safe keeping.
 
Bingo Dave! I have the subs well integrated and want to use them. Looks like I'll have to dig deeper into the isolation aspect.

This is why I bought an inexpensive table to start!

Gordon

Absolutely. With a TT, mechanical isolation is very important. Some TTs are also better at dissipating airborne vibrations too, and that also helps. With a well-isolated TT, there's no reason why you shouldn't be able to use your subs and your TT without problems. Good luck!
 
You will always get a bit of woofer pumping unless you have a perfectly flat record (which is rare).

The feedback thing is always going to be tough with a budget turntable. If you aren't already doing it, try taking the dust cover off when listening to records that may help a little.

The main thing will be to get the table isolated from your system. If set up properly, you should be able to use your sub with LP playback. But it will take a little bit of work.
 
You will always get a bit of woofer pumping unless you have a perfectly flat record (which is rare).

The feedback thing is always going to be tough with a budget turntable. If you aren't already doing it, try taking the dust cover off when listening to records that may help a little.

The main thing will be to get the table isolated from your system. If set up properly, you should be able to use your sub with LP playback. But it will take a little bit of work.

So, would I be correct in assuming that a budget TT is more susceptable to this than say a 2k table?

Gordon
 
I would be very surprised if it was the other way around.
 
So, would I be correct in assuming that a budget TT is more susceptable to this than say a 2k table?

Gordon

I think that would be a fair rule of thumb. The extra cash pays for more than just good looks! :)
 
I have troubles with my Project tt as it is WITHOUT a sub!
I'm going to build a shallow box, filled with sand, with the tt sitting on a granite tile, with a 1/2" gap between the box and the tile. And I'll have Euro-style underslung drawer slides underneath to be able to play with positioning a little. That should help with your feedback issue. Another way to isolate the tt would be to take the box & tile idea already mentioned, but place springs in between, instead of the sand. Dampen the springs with pieces of urethane foam between the coils of the springs. Those ideas are, um, on the table for me to try out!:rolleyes:
 
The first major issue I'm experiencing is woofer pumping.

You mentioned you bought this combo as an experiment, but I can tell you that the results you are going to get from this combo aren't going to tell you anything about what better turntables, arms, cartridges and phono sections can do.

Speed stability and isolation from all kinds of noises is what turntables are primarily all about. I use a VPI Aries 3 with a REL Stadium III for music and there is barely any sub pumping even at max volume. I have the table sitting on a custom made granite shelf - barely 6 ft away from the tt, and the the only other isolation is whatever the rack offers. I get pumping when I tap the turntable at very high volume levels, but it dissipates quite quickly - that's what a high end turntable does well, among other things.

Someone else mentioned the Thorens 126 they have, which offers pretty good isolation too. I can attest to this as well, having been a 126 owner decades ago.

Peter
 
I have troubles with my Project tt as it is WITHOUT a sub!
I'm going to build a shallow box, filled with sand, with the tt sitting on a granite tile, with a 1/2" gap between the box and the tile. And I'll have Euro-style underslung drawer slides underneath to be able to play with positioning a little. That should help with your feedback issue. Another way to isolate the tt would be to take the box & tile idea already mentioned, but place springs in between, instead of the sand. Dampen the springs with pieces of urethane foam between the coils of the springs. Those ideas are, um, on the table for me to try out!:rolleyes:

I did something similar under each speaker and under my subwoofer too.

When I placed one of the sand boxes under the table it seemed to suck all the life and energy out of it so I removed it. I did the same with the speakers, but I put a steel plate under the speakers instead of tile and it extended the highs and helped the rhythm.

FYI; Prettier than most other turntable wall shelves is the Quadraspire. They sell them at my local Linn dealer.

http://www.quadraspire.com/

Q4 Wall Bracket
http://www.divineaudio.co.uk/furniture/brackets/quadraspire-q4-wall-bracket-ex-shelf-/prod_853.html
quadraspire_q4wall.jpg
 
I think there is some debate whether or not there is any encoded information in a record which a subwoofer is supposed to reproduce..

Really? Though very few instruments go down to subwoofer levels, the ambience of the hall and the dynamics of orchestral music require the low frequencies that are on an album to be reproduced. Very few speakers will do this w/o a sub. I actually have an album (Organ Works of Bach and Franck, Chalfont SDGX 306/307) with bass below 16Hz, not that I can reproduce it, but I have heard it on systems that can.

I use a subwoofer for HT only.

What about digital?

However on my old set up for 2-channel the sub seemed to slow down the music and destroyed the stereo signal by splitting it (via piggy back wires). The sub sometimes picked up my footsteps, and you could forget about tapping on the turntable base - it would go crazy.

Your TT was poorly isolated and the feedback, even if it wasn't running away and howling, was ruining your PRaT and stereo signal. Acoustical feedback, both through the floor and acoustically was the problem, not the sub per se.

Maybe if you isolated the table better or spent + $10,000 on a turntable you could have rumble free subwoofer use.

I haven't spent anywhere near $10K and my table is totally? free of any feedback artifacts. I can jump up and down right in front of it ( as my daughters love to do, especially the 4 yo.) and no problem. Tapping on the plinth causes no sound whatsoever through the speakers, even with the volume set at levels at which I would never listen.

Suspended tables have a large advantage in this aspect of analog reproduction. Non-suspended tables require much more careful set-up in this regard IME.
 

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