Rumble down below

[PS Audio]

<!-- #thumb --> <p>Turntables are now cool. *The in*thing to have. *This nouveau*movement sees a lot of first timers. *How many Nubies know about rumble and record warp?</p>
<p>I suspect many inductees into the world of vinyl have high expectations that the new turntables and electronics that support them are somewhat plug and play. *In some cases that’s true, but I’ve seen too many times users get poor results if they don’t have at least a minimal knowledge about some of the problems. *Certainly rumble and warp are among those hidden down deep in the grooves of this revived medium.</p>
<p>Rumble is a very low frequency sound that typically is generated from the movement of the turntable platter spinning the record. *Record warp can be a result of disc damage or poor handling of that disc in the stamping process. *In both cases, any speaker with a decent woofer will show signs of both. *In some cases, particularly record warp, the results can be severe enough to shut down the power amp or really wreak havoc on the woofer. *Think of my Infinity IRS system on a disc that is even slightly warped. *Those woofers can move in a gut wrenching amount of subsonics.</p>
<p>Most modern and well designed turntables really haven’t much in the way of rumble. *In the good old days, many tables had a great deal of this low frequency noise, but that’s been reduced to acceptable levels in decent designs. *Record warp, on the other hand, is fairly common and many discs suffer from heat damage by warping slightly.</p>
<p>What can one do about these problems? *Older electronics used to have a switchable rumble filter that could remove most of these low frequency issues, but these dramatic filters also seemed to remove much of the bass as well. *You don’t see switchable rumble filters on electronics much anymore, so now you have to look at the specs or ask the manufacturer how they’ve dealt with this issue.</p>
<p>In the case of our phono product, the NuWave Phono Converter, for example, we place a very steep high pass filter starting at a very low 5Hz and dropping the sound off below that rapidly. *This has no effect on even the lowest notes possible on a vinyl recording, but effectively eliminates turntable rumble and dramatically reduces record warp.</p>
<p>So if you’re just getting into the fun of LP’s, make sure your electronics has a built in rumble filter that isn’t intrusive to the sound. *It makes this a lot more enjoyable.</p>
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[Source: http://www.pstracks.com/power/rumble/12125/]

 

[BobM]

I replaced my totally functioning Dynavector 20X-H with an XX-1 some years ago to check out LOMC's. It was used, but in fine shape, and it was also noticeably heavier than the 20X-H and lower in output. I needed a step-up for it. The detail and music coming out of it was wonderful, and sold me on the benefits of LOMC's, but I definitely heard a rumble.

Well after trying so many types of mechanical and electrical isolation to track it down and alleviate the low level noise, with no improvement, I finally decided to replace the cartridge. I got a Transfiguration Temper and the rumble was gone. I concluded that the problem was a mismatch in compliance between the arm and cartridge, which makes sense.

 

[MusicDirector]

I'm beginning to believe that "rumble" is a myth. I've had and have several very inexpensive TTs and not a single one produced any rumble at any time, at least not detectable to the human ear of even a most discerning listener. As for warp effects, I don't find a warped record of any degree to produce rumble. Most severely warped records will skip or not play at all depending on tone arm and cart. I have about 3 obviously warped records ranging from "will that one actually play?" to "well, it looks slightly warped when sitting on the platter" in my collection and one TT tracks them with no problem (I'll never understand how it does that). On another TT they won't play, the cart and tone arm fly all over the place in the attempt. Perhaps by dumb luck I have matched carts and tone arms? I don't know. Perhaps it really is just luck and nothing more?