Why do bass drivers go nuts when playing vinyl

[markw]

whereas with exactly the same piece of music on CD, they hardly move, even though the resultant sound *seems* the same? Never understood why this happens - anybody?!

The turntable itself produces a lot of very low, high level, sometimes inaudiable frequency mechanical rumble that's transmitted thru the tt itself, through the cartridge anf finally to the amp where it sucks up a lot of amplifier power moving those speakers. That's what rumble filters are for.

Second, feedback. Sound generated from thespeakers is picked up by the TT and cartridge and amplified over and over again. Sometimes, if you play it to loud it can break out in a howl. In thjis case, decopuling the TT from the speakers can help tremendously.

[TerryB]

I see! So why isn't there a similar mechanical rumbling noise from the transport of a CD player, or is this totally different?

Is the presence of this noise an indication of an inferior turntable, or do they all do it?

cheers

[markw]

Tt's depend on a needle wiggling in a groove and generating an analog electrical signal in a cartridge. If something makes that needle wiggle, it will get amplified. A CD player relys on light reflecting off of a surface and producing a stream od on/off pulses

As such, you can pretty much walk with 'em and have not too many problems. Granted, a skip buffer is needed to assure the continus delivery of the signal under physicaly demanding conditions but on the whole they are pretty immune from physical vibration infecting the signal chain.

All TT's have some rumble. The better the turntable, the less rumble it will have.

[E-Stat]

Is the presence of this noise an indication of an inferior turntable, or do they all do it?

No, they do not all do it. Modern units are dead quiet and generate very little rumble. Isolation devices are used to address mechanical feedback.

rw

[TerryB]

So should i look to eliminate this rumble? My tt playback quality really is on a par with my CD, at what is really a fraction of the cost! I just can't live with the surface noise and lack of direct access unless i'm having an enthusiastic hour or so with the 12" singles! Would i notice a difference at the speakers if this rumble was minimised?

[shokhead]

You answered your own question.

[markw]

We've obviously transversed from a speaker to a vinyl issue. Vinyl is still a viable alternative but there some inherent issues that you must learn to live with.

No matter what TT you have, there will always be some surface noise and, aside from an ancient ADC turntable, I can't think of any that will address your direct access issues.

And, the statement that new TT's are deas silent is a bit of an exaggeration. While rumble can be minimized, it's always there. Please note that he qualified that statement in the next sentence. Also, please be aware that certain speaker designs and placement in the room can accentuate this cone movement situation. Ported speakers tuned to a low frequency are a good example of this.

You also might inquire as to the costs of some of these "dead silent" turntables some people refer to.

[E-Stat]

And, the statement that new TT's are deas silent is a bit of an exaggeration.

Unless you are referring to an idler wheel driven changer, I stand by my comments. It doesn't take a $10k turntable to be free of mechanical noise audible by the average system. My 30 year old Ariston RD-11s still fits that bill. You will only hear the motor if you place your ear within inches of it. There are any number of inexpensive DIY isolation tricks around using bicycle tire innertubes and maple butcher blocks that address what is the more likely cause of most folks' problems. I use a twenty year old VPI HW-1 isolation base.

You also might inquire as to the costs of some of these "dead silent" turntables some people refer to.

You can get a new Rega for about $500. Indeed my new VPI Scout runs twice that without tonearm. Better still, you can buy a used Rega, Thorens, Ariston, Music Hall etc. turntable for less. There is a Thorens TD-160 on Audiogon now for $200. Here's a website devoted solely to Thorens:

http://www.theanalogdept.com/thorens_gallery.htm

rw

[risabet]

The turntable itself produces a lot of very low, high level, sometimes inaudiable frequency mechanical rumble that's transmitted thru the tt itself, through the cartridge anf finally to the amp where it sucks up a lot of amplifier power moving those speakers. That's what rumble filters are for.

Second, feedback. Sound generated from thespeakers is picked up by the TT and cartridge and amplified over and over again. Sometimes, if you play it to loud it can break out in a howl. In thjis case, decopuling the TT from the speakers can help tremendously.

A properly designed and maintained TT does not produce any audible rumble. In all likelihood, the cause of your problem is infrasonics caused by the arm/cartridge resonance frequency. This can be aggravated by record warps or an improperly matched cartridge/tonearm but any modern table shouldn't rumble audibly. In my opinion there is no comparison between well done analog and CD, analog wins every time.