Technics direct drive turntables
 

"Arny Krueger" wrote in message
...
"David Looser" wrote in
message

Are you seriously suggesting that using a Linn turntable
rather than a Technics one makes any difference at all to
the "dynamics, imaging and tone"?

It is possible, and some potential explanations follow.

The cartridge, and to a
lesser extent the arm will make an audible difference,
but not the turntable.

When people talk about their perceptions of differences in turntable sound
quality, they are generally talking about the entire ensemble - table,
arm, cartridge, often the whole rest of the audio system is different as
well. No way is the comparison time-synched, level-matched and
bias-controlled.


Absolutely. Creating those 'identical' conditions is beyond most ordinary
'hifi enthusiasts' in their own home.

My own method is/was to compare similar items over a few of some weeks or
months, during which time other items in the replay chain might have been
changed anyway. I simply chose the one I *liked best* as the winner, when
making comparisons. (Not interested in *measurements*!)



Any turntable that goes round at
the right speed, with minimal speed variation (wow) and
rumble, will sound the same as any other.

Plus/minus the other system differences and other issues such as isolation
from environmental vibrations.

I'm probably the only regular poster who has done full-monte comparisons
of LP playback equipment, right down to using LPs that were fresh out of
the wrappers and had the same stamper numbers.

Do it all right and things often sound shockingly similar:

http://home.provide.net/~djcarlst/abx_phca.htm



See above....

Technics direct drive turntables
 

"David" wrote

Try turning your volume knob to number 11.

Many, many years ago there was a lot of talk in the HiFi mags about acoustic
feedback to record decks. So I tried an experiment, using radio as the
source I turned my system up as loud as I could tolerate it (much louder
than I would ever have chosen to listen). Then whilst this was blasting away
I played the HFS69 test record (tone and silent grooves tracks) on my
Thorens TD150 (TP13 arm and Shure M75 cartridge) and recorded the output.
Afterwards I listened to the tape playback to see if I could detect any
signs of acoustic feedback from the speakers - there wasn't a trace, the
"silent" groove had the expected surface noise, but no hint of anything from
the very loud radio. Similarly the tone suffered from the expected problems
that you have to put up with from vinyl and analogue tape, but again nothing
that hinted of acoustic feedback.

My conclusion was that all this stuff about acoustic feedback was just
another version of the paranoia that seems to affect HiFi obsessive when
they become convinced that their HiFi system would sound a lot better if
only they change something (which probably involves spending a lot of
money).

So no, I do not accept that your previous comment about vibration and air
movements somehow or other becomes valid when you turn the volume up.

And quite seriously if you think that record decks do suffer in this way why
bother with them? There are plenty of alternative audio sources around these
days.

David.

Technics direct drive turntables
 

"David Looser" wrote in message
...
"David" wrote

Try turning your volume knob to number 11.

Many, many years ago there was a lot of talk in the HiFi mags about
acoustic feedback to record decks. So I tried an experiment, using radio
as the source I turned my system up as loud as I could tolerate it (much
louder than I would ever have chosen to listen). Then whilst this was
blasting away I played the HFS69 test record (tone and silent grooves
tracks) on my Thorens TD150 (TP13 arm and Shure M75 cartridge) and
recorded the output. Afterwards I listened to the tape playback to see if
I could detect any signs of acoustic feedback from the speakers - there
wasn't a trace, the "silent" groove had the expected surface noise, but no
hint of anything from the very loud radio. Similarly the tone suffered
from the expected problems that you have to put up with from vinyl and
analogue tape, but again nothing that hinted of acoustic feedback.

My conclusion was that all this stuff about acoustic feedback was just
another version of the paranoia that seems to affect HiFi obsessive when
they become convinced that their HiFi system would sound a lot better if
only they change something (which probably involves spending a lot of
money).

So no, I do not accept that your previous comment about vibration and air
movements somehow or other becomes valid when you turn the volume up.

And quite seriously if you think that record decks do suffer in this way
why bother with them? There are plenty of alternative audio sources around
these days.

The problem I see with your experiment is that your source did not
necessarily have the same spectra as would be observed with a turntable
operating on the verge of acoustic (or architectural) feedback. I have a
number of friends with truely heroic subwoofers and none of them can use a
TT as a source without significant high pass filtering.

Technics direct drive turntables
 

"David" wrote in message
...
"Arny Krueger" wrote in message
...

I'm probably the only regular poster who has done full-monte comparisons
of LP playback equipment, right down to using LPs that were fresh out of
the wrappers and had the same stamper numbers.

Do it all right and things often sound shockingly similar:


So you admit that they don't sound the same then? Well done!

Check the reference I provided.


http://home.provide.net/~djcarlst/abx_phca.htm



Not always, but they sometimes do.

Technics direct drive turntables
 

"Arny Krueger" wrote

I have a number of friends with truely heroic subwoofers and none of them
can use a TT as a source without significant high pass filtering.

Then I suggest that either your friends are ignoring basic common-sense with
regard to relative positioning and support isolation between the TT and the
speakers. Or they are listening at the sort of sound-levels that cause
permanent hearing damage, probably both.

David.

Technics direct drive turntables
 

"David Looser" wrote in message
...
"Arny Krueger" wrote

I have a number of friends with truely heroic subwoofers and none of them
can use a TT as a source without significant high pass filtering.

Then I suggest that either your friends are ignoring basic common-sense
with regard to relative positioning and support isolation between the TT
and the speakers.

Try again. These are practicing, degreed engineers specializing in audio.

With all due respect I suspect that you have no practical technical
experience with subwoofers capable of 120+ dB @ 10 Hz with low distortion.

Or they are listening at the sort of sound-levels that cause permanent
hearing damage, probably both.

Try again.

I suspect that you have never even listened to subwoofers capable of 120+
dB @ 10 Hz with low distortion.

The ear is very tolerant of very high SPLs at low frequencies. That's why
you can open the windows of your car at 60 mph and not be permanently
deafened.

Look at the Fletcher Munson curves and reasonably extrapolate them to 10 Hz.
Note what the approximate threshold of hearing is at 10 Hz.

Technics direct drive turntables
 

In article , Arny
Krueger
wrote:


With all due respect I suspect that you have no practical technical
experience with subwoofers capable of 120+ dB @ 10 Hz with low
distortion.

Certainly true in my case.

Look at the Fletcher Munson curves and reasonably extrapolate them to 10
Hz. Note what the approximate threshold of hearing is at 10 Hz.

True enough. However I'm wondering how often this is needed for music. I
can see that some organ notes may require high levels below 20Hz, and
perhaps some special cases like thwacks on big drums. But beyond that is it
more likely to be a 'requirement' for the bangs and thuds of film
soundtracks than mere music? The lowest bass guitar notes I know of
off-hand is at about 30-35Hz IIRC on a Little Feat album.

Am I also correct in suspecting that by the time you get down to such low
frequencies the effect on LP replay is primarily because we are in the
region of the resonances of the the arm-stylus and TT suspension?

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Technics direct drive turntables
 

"Jim Lesurf" wrote in message
...
In article , Arny
Krueger
wrote:


With all due respect I suspect that you have no practical technical
experience with subwoofers capable of 120+ dB @ 10 Hz with low
distortion.

Certainly true in my case.

Look at the Fletcher Munson curves and reasonably extrapolate them to 10
Hz. Note what the approximate threshold of hearing is at 10 Hz.

True enough. However I'm wondering how often this is needed for music. I
can see that some organ notes may require high levels below 20Hz, and
perhaps some special cases like thwacks on big drums. But beyond that is
it
more likely to be a 'requirement' for the bangs and thuds of film
soundtracks than mere music? The lowest bass guitar notes I know of
off-hand is at about 30-35Hz IIRC on a Little Feat album.

Am I also correct in suspecting that by the time you get down to such low
frequencies the effect on LP replay is primarily because we are in the
region of the resonances of the the arm-stylus and TT suspension?


You are correct on all counts. The only acoustic instrument capable of
creating these sorts of levels at sub-audible frequencies is the pipe organ.
And the conventional vinyl replay system creates a lot of sub-audible noise
whilst being incapable of replaying recorded material at these frequencies
(even assuming they were there on the disc in the first place, normally the
cutting engineer would filter them out if present on the tape).

"Heroic" sub-woofers of the type mentioned by Arny are normally only found
in cinemas, where they are driven by the "LFE" (low-frequency effects) track
(the point one of the 5.1 soundtrack). This is used to give "body" to things
like explosions etc, rarely music.

So my thoughts on this is that anyone who actually wants to use "heroic"
subwoofers should avoid sourcing them with vinyl. I would have thought that
*very* few people are in a position to use such levels at sub10Hz
frequencies in a domestic audio system (they are hardly family, or
neighbour, friendly), so whilst Arny is technically correct, the issue is
irrelevant to vinyl replay.

David.

Technics direct drive turntables
 

David Looser said...

I would have thought that
*very* few people are in a position to use such levels at sub10Hz
frequencies in a domestic audio system (they are hardly family, or
neighbour, friendly), so whilst Arny is technically correct, the issue is
irrelevant to vinyl replay.

I route all audio signals through my stereo system; TV/radio/ video
games etc. A few years ago I was given a crapola "sub woofer" by
someone, so connected it up. While it did add something to movies where
you are expecting semi-realistic thumps, for general use it was so
annoying that I dumped it fairly rapidly. It emphasised all the
unintended "noises off" which occur but are rarely noticed; such as
wind noise in outside broadcasts and the occasional thumps and bangs in
live studio stuff, microphone knocking, etc. But most annoying was the
bloody non stop drumming on TV intros and themes such as the news and
those crashes which signal rounds in Weakest Link and also in adverts.
Also as Arnie says LP playback was a problem, always on the verge of
breaking into feedback it seemed, it is vaguely amusing watching the
bass drivers on the main speakers making heroic efforts to achieve 1"
excursion but worrying. The final straw was an episode late one night
when listening to Janice Long on Radio 2; Janice played a new track and
was so taken with it that she banged out a drum roll on the studio desk
which must have bypassed the microphone suspension/isolation system and
was transmitted in all its room shaking glory, I nearly crapped myself
and Henry the cat who liked lounging on the sub in the corner got the
fright of his life.


--
Ken O'Meara
http://www.btinternet.com/~unsteadyken/

Technics direct drive turntables
 

"UnsteadyKen" wrote in message
m...
David Looser said...

I would have thought that
*very* few people are in a position to use such levels at sub10Hz
frequencies in a domestic audio system (they are hardly family, or
neighbour, friendly), so whilst Arny is technically correct, the issue is
irrelevant to vinyl replay.

I route all audio signals through my stereo system; TV/radio/ video
games etc. A few years ago I was given a crapola "sub woofer" by
someone, so connected it up. While it did add something to movies where
you are expecting semi-realistic thumps, for general use it was so
annoying that I dumped it fairly rapidly. It emphasised all the
unintended "noises off" which occur but are rarely noticed; such as
wind noise in outside broadcasts and the occasional thumps and bangs in
live studio stuff, microphone knocking, etc. But most annoying was the
bloody non stop drumming on TV intros and themes such as the news and
those crashes which signal rounds in Weakest Link and also in adverts.
Also as Arnie says LP playback was a problem, always on the verge of
breaking into feedback it seemed, it is vaguely amusing watching the
bass drivers on the main speakers making heroic efforts to achieve 1"
excursion but worrying. The final straw was an episode late one night
when listening to Janice Long on Radio 2; Janice played a new track and
was so taken with it that she banged out a drum roll on the studio desk
which must have bypassed the microphone suspension/isolation system and
was transmitted in all its room shaking glory, I nearly crapped myself
and Henry the cat who liked lounging on the sub in the corner got the
fright of his life.


I suspect you were getting a room-resonance problem. When sub-woofers were
first introduced into cinema sound systems it was found necessary to include
a parametric equaliser in the feed to the sub-woofer to notch out
frequencies around the room resonance, otherwise you get this irritating
"one-note bass" effect at the frequency of the room resonance.

In cinemas the main speakers have a reasonable bass response, 20Hz or so,
and the sub-woofer is connected only to the LFE channel, so sub-LF crap on
the main channels isn't fed to the sub-woofer. But in home cinema systems
it's common practice to use small speakers for the main channels with little
LF below 70-100Hz or so, and the AV amp will divert the bass from the main
channels into the sub-woofer. It's very hard to get that to sound right IMO.

I was amused by a recent article in "Cinema Technology" about getting the
best from the multi-channel uncompressed audio that is part of digital
cinema. The writer at one point, talking about speaker placement, commented
that "the sub-woofer can go anywhere - preferably in the skip", a sentiment
that I have a lot of sympathy for.

David.