Woofer movement on CD v vinyl
Posted by: silklee on 28 October 2002
I see that when I am playing vinyl, the woofers seems to move more. It even looks like it might jump out of the speaker’s cabinet. But it is not so when I am playing cds.
Anyone knows what is the technical reason for that?
Anyone knows what is the technical reason for that?
Posted on: 28 October 2002 by silklee
My setup is P25/CD5/92R/90/ES14. Its actually not a complaint. Just an observation. No detriment to the music observed.
Posted on: 28 October 2002 by Martin Clark
The reason is quite simple - it's due to dragging a small rock through a bumpy groove.
Records are cut pre-equalised using the RIAA curve literally to fit the bass on there; the signal has to be compressed to get more than a couple of minutes a side. Bass is cut during mastering and boosted by your phono stage on playback; but so is every other LF disturbance that the cartridge picks up below 500Hz. These include warp, wow and footfall/suspension related movement, arm/cartridge resonances etc. The result is large, spurious LF excursion of the cone which may or may not be related to the music signal.
It's a primary reason why support and setup makes such a difference to turntable sound, why there is world of difference between suspended and non-suspended decks, why Townshend uses a damping trough...and why CD shows none of these problems, but maybe also gives up some of the 'magic'.
M.
Records are cut pre-equalised using the RIAA curve literally to fit the bass on there; the signal has to be compressed to get more than a couple of minutes a side. Bass is cut during mastering and boosted by your phono stage on playback; but so is every other LF disturbance that the cartridge picks up below 500Hz. These include warp, wow and footfall/suspension related movement, arm/cartridge resonances etc. The result is large, spurious LF excursion of the cone which may or may not be related to the music signal.
It's a primary reason why support and setup makes such a difference to turntable sound, why there is world of difference between suspended and non-suspended decks, why Townshend uses a damping trough...and why CD shows none of these problems, but maybe also gives up some of the 'magic'.
M.
Posted on: 28 October 2002 by Paul Ranson
I don't think it's necessarily that simple.
Excessive woofer flapping may be a symptom of mismatched arm/cartridge, or acoustic feedback or a poorly engineered phono stage (surely not in this case...) the input should roll off extreme low frequencies.
So it may be worth examining the cartridge, tracking weight, turntable mounting arrangements etc.
Paul
Excessive woofer flapping may be a symptom of mismatched arm/cartridge, or acoustic feedback or a poorly engineered phono stage (surely not in this case...) the input should roll off extreme low frequencies.
So it may be worth examining the cartridge, tracking weight, turntable mounting arrangements etc.
Paul
Posted on: 28 October 2002 by Noel
Many turntables will pickup subsonics from their environment. Support tables should minimise this. I have only found this to be a problem on suspended floors. In one house the woofers would move if a heavy truck went past. Some of the less well designed wall supports also transmit these frequencies. Its surprisingly common.
Posted on: 28 October 2002 by Brucie
I'm no expert but I think Martin's explanation is by far the most likely. I have always noticed this woofer effect when playing records but have never felt it hindered my enjoyment nor made me want to put a CD on rather than an LP. Its just background rumble as far as I'm concerned what ever floor you have.
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Posted on: 28 October 2002 by JosephR
Agree with Brucie, it's rumble that causes these woofer movements. Different turntables have different rumble figures. Like the thinner-platter Gyrodec has more rumble than the Orbe.
Also, warps can cause these woofer movements. On a hump, the cart goes up with it, and causes low-level signals that cause the woofer to have more excursions than before.
Also, warps can cause these woofer movements. On a hump, the cart goes up with it, and causes low-level signals that cause the woofer to have more excursions than before.
Posted on: 28 October 2002 by Greg Beatty
...if the movements correspond to footfalls. My LP12 does this (even through my frequency-limited Sony ES series receiver) and it is sited on top of a 250+ pound tele. I need to wall-mount the bugger.
- GregB
Insert Witty Signature Line Here
- GregB
Insert Witty Signature Line Here
Posted on: 28 October 2002 by Craig B
Rumble is a measure of the decks spurious noise level independent of environmental feedback, recorded material and/or arm/cartridge choice.
Ortofon, long ago developed a highly accurate means of measuring rumble via a stylus support that was attached directly to the turntable spindle via a precision jewelled bearing pivoting assembly. As the deck rotated, bearing and motor noise were measured via the stylus picking up the transmitted noise.
On decent decks rumble is at a very low level relative to that of the music signal. Not CD quiet mind, but very good as to not get in the way of the music.
Large bass driver excursions are a result of the affects of various stimuli being amplified along with the bass notes by the RIAA playback equalisation that Martin has mentioned above. Some of the scariest bass driver excursions that I have ever experienced where when playing ripple warped 45 rpm EPs that contained heavy 120+ bpm synthesized bass lines.
Let's just call these affects 'Extraneous Low Frequency Shite' or 'ELFS' shall we?
Craig
Ortofon, long ago developed a highly accurate means of measuring rumble via a stylus support that was attached directly to the turntable spindle via a precision jewelled bearing pivoting assembly. As the deck rotated, bearing and motor noise were measured via the stylus picking up the transmitted noise.
On decent decks rumble is at a very low level relative to that of the music signal. Not CD quiet mind, but very good as to not get in the way of the music.
Large bass driver excursions are a result of the affects of various stimuli being amplified along with the bass notes by the RIAA playback equalisation that Martin has mentioned above. Some of the scariest bass driver excursions that I have ever experienced where when playing ripple warped 45 rpm EPs that contained heavy 120+ bpm synthesized bass lines.
Let's just call these affects 'Extraneous Low Frequency Shite' or 'ELFS' shall we?
Craig
Posted on: 28 October 2002 by garyi
It might be due to the fact you have the volume higher to get the same level of enjoyment from the deck. The 90 is struggling and not controlling the drivers?
Seems resonable in my mind. When I had the 92/90 the drivers seem to move a lot more than nower days, who knows mabye I am mad.
Seems resonable in my mind. When I had the 92/90 the drivers seem to move a lot more than nower days, who knows mabye I am mad.
Posted on: 28 October 2002 by Martin Clark
..at least no madder than I must be - I've had the same effect with homebrew amplifiers. Turning up the wick on an amp with a weedy (test) power supply caused the effective DC operating point to move enough it looked like I'd be wearing the cones if I kept it up!
Mind you, if this was the case with silklee's 90 it would also happen with the CD input.
M.
Mind you, if this was the case with silklee's 90 it would also happen with the CD input.
M.
Posted on: 28 October 2002 by Martin Clark
..after 3 years+ I finally get to my hundredth post and it's technobabble not directly pertinent to enjoying music.
Memo to self: get out more.
M.
Memo to self: get out more.
M.