Why do bass drivers go nuts when playing vinyl

[TerryB]

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?!

[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.

[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.

[dean_martin]

check out the "cone flap" thread in the analog forum started by dba and the link to another thread posted by royphil in response.

[Woochifer]

The issue with vinyl is exactly as markw described. Low frequency rumble is pretty common with vinyl playback, no matter how good the isolation is. Some of it is mechanically induced, but some of it also originates with the vinyl pressing itself. Off-center holes, less-than-flat LPs, surface irregularities, bad mastering, etc. can all contribute.

The thing about the vinyl rumble is that a lot of it occurs in an inaudible low frequency range. With ported speakers, this often occurs below the tuned port frequency, so the cone movement is undampened in that range and might look worse than it actually is (you get a lot of movement, but it won't produce any audible effects aside from possibly reduced coherency in the higher midbass and midrange frequencies above the port frequency).

If you look at older receivers and preamps, you'll note that a lot of them have subsonic filter switches on them. Those switches were put in place because of how common the subsonic rumble was with vinyl playback.

[BRANDONH]

If you look at older receivers and preamps, you'll note that a lot of them have subsonic filter switches on them. Those switches were put in place because of how common the subsonic rumble was with vinyl playback.

Intresting.
My amp has a subsonic filter switch on it. I have never used it because the manual said it could make the bass sound rubbery I only use the clip limiters.
But I am going to try switching it on and see If I can hear a difference when I am playing back Vinyl.
Thanks

[Woochifer]

Intresting.
My amp has a subsonic filter switch on it. I have never used it because the manual said it could make the bass sound rubbery I only use the clip limiters.
But I am going to try switching it on and see If I can hear a difference when I am playing back Vinyl.
Thanks

The subsonic filters only kick in well under 20 Hz. You won't have a lot of material that extends into that range, so I doubt that it would make for "rubbery" sounding bass.

Like I said, they were primarily put in because of how common that low frequency rumble is with vinyl playback. It was primarily put in place to protect speakers from overexcursion and to save the amp from having to drive those low frequencies. It's not supposed to have an audible effect aside from whatever comes through saving your speakers and amp from doing all that extra work.

[E-Stat]

The subsonic filters only kick in well under 20 Hz. You won't have a lot of material that extends into that range, so I doubt that it would make for "rubbery" sounding bass.

Actually, he uses a pro amp with a 50 hz low frequency filter as well. Has clip limiters, too.

When was the last time you saw a rumble filter on a modern phono preamplifer?

rw

[RGA]

Okay this is my third time trying to post this so I give up... An's design on cd can be seen on the net --- for complete and correct stance look there rather than me trying to reduce it simply -- why - it's merits are out there already listed - they don;t use any digital filtering and they are direct from disc designs -- they sound nothing like the opriginal players.

I was not saying either or with vinyl or cd -- some albums you can only get on vinyl - I listen to cd just as much as vinyl. My sample size is random I feel enough to warrant my inkling that unless the vinyl is damaged or was a poor print it has thus far for me been superior to the same album on cd. Even if one wants to believe it is the cd recording process that is at fault still makes no difference because if the giood version is on vinyl then it's the technology you NEED to have to get the better sound.

This is also why we need Redbook CD and the reason Peter built a cd player in the first place because a lo9t of music he loved was ONLY being preserved on cd -- to hear it he needed a cd player -- only to him they all sucked --- so he went out to make it better...whether one agrees with it or not can simply be auditioned.

[BRANDONH]

Actually, he uses a pro amp with a 50 hz low frequency filter as well. Has clip limiters, too.

When was the last time you saw a rumble filter on a modern phono preamplifer?

rw

My unit does both 20 or 50 Hz which one should I choose?

LF filter freq. select (20 or 50 Hz)

[Woochifer]

Actually, he uses a pro amp with a 50 hz low frequency filter as well. Has clip limiters, too.

And that would not be a subsonic filter (at least the kind that I was describing) because it cuts off the frequencies well into the range where you still get content that's part of the source. The switches that I was describing only kick in where the signal content is primarily limited to low frequency noise.

When was the last time you saw a rumble filter on a modern phono preamplifer?

Subsonic filters were never limited just to phono preamps. Integrated amps and two-channel preamps have frequently incorporated the feature; though not as common nowadays since the filters were frequently part of same signal path as the tone controls, and the general approach nowadays with two-channel is eliminate any signal altering switches. Conrad-Johnson and Accuphase are a couple of the manufacturers I've seen that currently make preamps with switchable subsonic filters on board. And nowadays, the feature is very common with subwoofer amps and mobile audio equipment.

[Pat D]

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?!

Actually, the cause is quite probably the resonances caused by record warps on a tone arm and cartridge combination which have a resonance in the record warp range. If this is a problem, there are cartridges with a damper that looks like a brush.

As has been explained, when you have a speaker with a woofer which is undamped at such low frequencies (woofers audgmented by a port or passive radiator), there is nothing to keep the driver from moving back and forth to a considerable degree. It can muddy the music if severe enough. Remedies include a rumble filter or a better tone arm cartridge combination.

Low frequency feedback in the room can cause this, too. As has been mentioned, better isolation of the turntable may help, often just moving the turntable farther from the speakers--but that won't cure the above problem.

[Peter Duminy]

Risabet and Pat D are right IMHO, as many of the vintage amps like Quad for example, had a "Rumble Filter" on them. Most had a rolloff of 12dB/18dB below 18Hz - 15Hz depending on the model. They were very effective too. Fitting very high compliance cartridges in high mass tonearms with even slightly warped discs will give your woofers a workout they have never seen before!

[BRANDONH]

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?!

One day a friend of mine came over with a Rolling Stones "Some Girls" CD and I had it on the original Viny LP (before they removed the famous actors from the cover).
Anyway I popped in the CD and put the record on at the same time with both playing the same song I switched between the two and wow what a bass difference!
The vinyl blew away the bass reponse of the CD in fact it sounded altogether better that the CD my friend was amazed.
Long Live Analog.