Sub Sonic Filter for Turntable

[kap'n krunch]

Sorry G, but my solution would be : a sturdier TT...not putting yours down as bad but I mean STURDIER...I could recommend mine but... you never know if it'd lt me down!!!

EDIT: maybe that would be why your awesome TT is feeding back and my humble Technics from 1981 doesn't..the standard tonearm!!! The one in mine is really short and light...

 

[GOS]

Oh, I totally know my TT is a very modest TT. Kap - not gonna hurt my feelings. I've debated getting a more substantial TT, just haven't found the money and justification yet.

So - I have a Project Debut Carbon. I'll have to dig out the paperwork to see about the tonearm, etc. I did upgrade the stylus, will have to get paperwork on that too. I initially chose this one due to my desire to rip my vinyl. Yes, I know the story about how these medium to low grade TT that rip are inferior. Still, it was a financial decision, among other things.

So, for now, lets just figure out what I can do to improve the one I have. No, putting it in a box and buying a new one isn't gonna help me...lmao

 

[MidiMagic]

As a former service tech, I have dealt with such rumble many times.

Check the following:

- Is the vibration transmitted through the air, or through the structure?

- Is the vibration shaking the pickup or the record?

- Check the design of the RIAA phono stage. The RIAA specifies a sharp cutoff at 15 Hz. But many phono preamps omit this filter because records are also subject to this limit. I had to add it to mine.

- Try playing a different sound source through the speakers while listening to the phono through headphones. This breaks the feedback loop while still finding the point of picking it up.

- Try this again with the turntable not rotating.

- Concrete blocks do not help if the floor under them is vibrating.

- Shelves do not help if the wall is vibrating.

- Often I could damp out such vibrations by placing foam rubber between the sprung turntable plinth and the base underneath it.

- I built a sub-base of two slabs of plywood with foam rubber in between and rubber feet. But the rubber feet are spaced away from where the turntable feet are.

- Try putting the turntable inside a cabinet.

- Does it go away if your turn off the sub?

- Put the system into Dolby Surround or Pro Logic and try to determine the direction the sound comes from. From the front is horizontal shaking of the turntable. From the back, the shaking is vertical.

- There are sound levels above which nothing can stop this.

 

[J. PUPSTER]

- There are sound levels above which nothing can stop this.

That would be GOS turned up to 11 on his amp! But what’s changed from before?

 

[DennisMabry]

One quick question, have you tried removing the dust cover? They can act like sound boards on a guitar and pick up all of the room vibration.

I have had the same trouble when turned up loud. I never thought of the dust cover. I have covered my turntable with a heavy blanket. That helps, but possibly because it is damping the vibration of the cover. Will have to try that.

 

[markshan]

So - I have a Project Debut Carbon. I'll have to dig out the paperwork to see about the tonearm, etc. I did upgrade the stylus, will have to get paperwork on that too.

That table shouldn't have those issues. It ships with a carbon fiber arm, so don't worry about that part. Did you have the same problem with the stock cartridge? If so, it's not a compliance issue and there doesn't seem to be a dust cover, so that's not it.

 

[markshan]

I have had the same trouble when turned up loud. I never thought of the dust cover. I have covered my turntable with a heavy blanket. That helps, but possibly because it is damping the vibration of the cover. Will have to try that.

Let me know if it helps.

 

[GOS]

That table shouldn't have those issues. It ships with a carbon fiber arm, so don't worry about that part. Did you have the same problem with the stock cartridge? If so, it's not a compliance issue and there doesn't seem to be a dust cover, so that's not it.

No, it came with a dust cover...which I've never taken off. That's the easiest change I can try next.

 

[GOS]

Did you have the same problem with the stock cartridge

The stock cartridge was a lower grade Ortofon (don't remember which number) and I replaced it with a considerably higher quality Ortofon. Regardless, I certainly had the problem before the switch. When I had the TT on my rack, the rumble was impossibly terrible. Once I relocated to my current concrete blocks, with several hockey pucks under the blocks, and another pair under the TT, the rumble got WAY better.

But, I'm a picky fuQer, so any rumble totally seems unacceptable to me.

 

[markshan]

BTW, none of my suggestions are to say don't use a subsonic filter. They are just to say you may not need to. From my days doing live sound we had a saying... an ounce of signal is worth a pound of processing. In other words, do everything you can to clean up the signal path first. Then, if you still can't remedy the situation, add processing (the filter). Even if you end up needing the filter, you will still benefit from optimizing everything else first.

 

[markshan]

The stock cartridge was a lower grade Ortofon (don't remember which number) and I replaced it with a considerably higher quality Ortofon. Regardless, I certainly had the problem before the switch.

Then it is not a compliance issue. You can move on to the wall shelf if the dustcover trick doesn't satisfy. I can post all of the little do's and dont's of constructing one. If you need that info, just let me know.

 

[markshan]

- Concrete blocks do not help if the floor under them is vibrating.

- Shelves do not help if the wall is vibrating.

I think it would be more accurate to say they are less helpful if the surface under them is vibrating. Just like crumple zones in car building, there are ways to use a mixture of inert and dormant substances to minimize that transfer.

 

[GOS]

Just to say this....and I may be misunderstanding what is really happening...but consider this.

I have ripped my vinyl, with subwoofer engaged....and the rumble in the finished product is there. (Flac via Foobar)
I then (just recently) decided to re-rip the same vinyl, with the sub turned off. I still hear the rumble, when I turn it up. So, there is that.

Does that mean that the rumble is coming from the TT somewhere? Or not necessarily?

 

[atrocity]

Does that mean that the rumble is coming from the TT somewhere? Or not necessarily?

I don't have a straight answer for you, but if you're playing for the sake of digitizing, you might want to turn the speakers off completely and monitor using headphones. I always do that just out of (probably misplaced!) fear that I'm going to miss something. In your case, seeing what changes (or doesn't) with no speakers might be a useful data point.

Another thing to try is DeNoiseLF from the same guy who wrote ClickRepair. I've recently gotten in the habit of using it to eliminate rumble and hum from my captures and it works well. Though I only do it Because I Can, in my situation I haven't found the rumble to be obvious during normal listening. I can really hear it when I set DeNoiseLF to just output what it's removing, though!

I was going to link to the download, but the store is apparently currently being rebuilt. If you're interested but can't find it I can make it available. It has to be registered eventually, but there's a free trial period.

 

[J. PUPSTER]

Just to say this....and I may be misunderstanding what is really happening...but consider this.

I have ripped my vinyl, with subwoofer engaged....and the rumble in the finished product is there. (Flac via Foobar)
I then (just recently) decided to re-rip the same vinyl, with the sub turned off. I still hear the rumble, when I turn it up. So, there is that.

Does that mean that the rumble is coming from the TT somewhere? Or not necessarily?

Sounds like you need to adjust (finely align) your cart!

https://www.discogs.com/Hi-Fi-News-Analogue-Test-LP/release/3212139

 

[GOS]

Sounds like you need to adjust (finely align) your cart!

That could be! I find the adjustment process, fairly difficult. Yes, I know. It shouldn't be. I sort of get confused sometimes.....the wording. Turn counter clock-wise (or whatever)....I'm thinking.....counter clockwise is different depending on where you are looking at your TT. Anywho, yeah...I could look into that as well.

 

[J. PUPSTER]

That could be! I find the adjustment process, fairly difficult. Yes, I know. It shouldn't be. I sort of get confused sometimes.....the wording. Turn counter clock-wise (or whatever)....I'm thinking.....counter clockwise is different depending on where you are looking at your TT. Anywho, yeah...I could look into that as well.

One of the tests on that Test LP I linked to has certain freq. ranges that will make your cart. wobble and actually jump out of the groove if not properly aligned.

 

[GOS]

One of the tests on that Test LP I linked to has certain freq. ranges that will make your cart. wobble and actually jump out of the groove if not properly aligned.

Ooh. I didn't see that......I'll look for the link.

 

[J. PUPSTER]

Ooh. I didn't see that......I'll look for the link.

One big problem I have though with these kind of test LPs is- it may reveal what's not aligned properly, causing issues, but it doesn't address how to adjust to solve the problem; so yeah "tinker tinker PITA"
But if it works; credit goes to Freddie for passing that gassy idea to me

 

[LuvMyQuad]

Rip an LP with sub on, with sub off, and with all speakers off. Compare the rips. If the rumble is there with no speakers on its a TT issue. If it gets progressively worse as more bass is played in the room, its airborne or structural. A wall shelf will do wonders for the last condition.