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Re: TT acoustic coupling

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  • Robert Greene
    What is happening here is that ,because vinyl is no longer the primary medium, things that were common knowledge--and commonly available on test discs that
    Message 1 of 111 , Jun 2, 2008
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      What is happening here is that ,because vinyl is no longer the
      primary medium, things that were common knowledge--and commonly
      available on test discs that were everywhere, e.g., Shure's--are
      becoming esoteric, something like how to use an astrolabe or the the
      like. Almost no one really understood the physics, simple though it
      is, then,either, but people were led through the process of checking
      on this(and other things about vinyl) because vinyl was so wide-
      spread that it was worthwhile to have items that did the leading,
      worthwhile in monetary terms, I mean. Now it large is not.

      REG

      --- In regsaudioforum@yahoogroups.com, "Ted Rook" <rooknrol@...>
      wrote:
      >
      > Fred probably you have been doing this longer than I have, it seems
      our experience of test
      > discs varies, I was pleased recently to discover both types of test
      on the HFN disc 2 and I
      > stopped searching, was it more common previously? Also perhaps I
      was speaking rather
      > loosely about vinyl users in general rather than individuals here,
      don't you think that many are
      > uncurious about technical evaluation? That requires the type of
      mind which engineers have
      > and that's not everyone.
      >
      > Ted
      >
      > On 2 Jun 2008 at 13:21, Fred wrote:
      >
      > > Ted,
      > >
      > > As a universally documented aspect of tonearm
      > > adjustment with almost every test record including
      > > both lateral and vertical resonance tests, why would
      > > you infer that most people never give thought to
      > > vertical resonance?
      > >
      > > Fred.
      > >
      > >
      > >
      > > --- Ted Rook <rooknrol@...> wrote:
      > >
      > > > Thanks for the low mass arm recos Tom. I have a
      > > > pretty good grasp of tone arm and
      > > > cartridge dynamics but no motivation to put energy
      > > > and money into a low mass unit at
      > > > present there are other priorities that come first.
      > > >
      > > > I have to repeat myself here because I don't think
      > > > the message is getting through. This is all
      > > > about LP records not CD. Tone arm resonance may be
      > > > stimulated using test discs
      > > > specifically cut to activate either lateral or
      > > > vertical resonances. When most people talk about
      > > > resonance they mean horizontal. In my system the
      > > > lateral resonance is fine, if anything a little
      > > > low at about 8Hz but not a problem, it is above
      > > > warp/wow and below the audio band, end of
      > > > story. The vertical resonance, which I supect many
      > > > people may have never measured or
      > > > given any thought to is where the acoustic coupling
      > > > becomes significant in my system. The
      > > > amp and speakers can reproduce everything cleanly
      > > > all the way down to DC, there is no
      > > > problem with speakers or electronics, in fact there
      > > > is no problem and I hope people realise
      > > > this, I am not looking for help here, I have a neat
      > > > way of putting a high pass filter in the
      > > > system that suppresses the vertical resonance at
      > > > about 20Hz and prevents the low end from
      > > > being muddied. People are saying ah but the high
      > > > pass filter introduces phase shift. My
      > > > response is I can't hear it as a problem, it may be
      > > > there but with LP source material I can't
      > > > hear it whereas I can the benefit of the resonance
      > > > being supressed. A good compromise I
      > > > think.
      > > >
      > > > Regarding mistracking I'd like to find a way to
      > > > evaluate your claim about the stylus "bouncing
      > > > around" in the groove, I am persuaded otherwise by
      > > > what I hear and measurements made
      > > > during antiskate adjustments. These measurements
      > > > quite clearly show this to be a linear
      > > > thing, harmonic distortion rises as the antiskate is
      > > > reduced and reducing it further eventually
      > > > results in bursts of gross distortion. It is
      > > > avoidance of the gross bursts that is the aim of
      > > > antiskate and it works. I'm operating in the linear
      > > > controlled region, well away from the gross
      > > > bursts. I can believe that the gross distortion if
      > > > allowed to occur would cause groove damage
      > > > but then I don't allow that to occur so I don't have
      > > > any concerns about uncontrolled stylus
      > > > motion, it is audible and it is not happening in my
      > > > system, there may be some who are new to
      > > > vinyl and would allow that to occur but I'm not one
      > > > of them. So my concern with ordinary wear
      > > > remains the number one priority and at 1.25 grams
      > > > I'm at the upper limit of the
      > > > manufacturer's recommendation.
      > > >
      > > > Ted
      > > >
      > > >
      > > >
      > > >
      > > >
      > >
      > >
      > >
      > > __________________________________________________________
      > > Sent from Yahoo! Mail.
      > > A Smarter Email http://uk.docs.yahoo.com/nowyoucan.html
      > >
      > >
      > > ------------------------------------
      > >
      > > Yahoo! Groups Links
      > >
      > >
      > >
      > >
      > >
      > > --
      > > No virus found in this incoming message.
      > > Checked by AVG.
      > > Version: 7.5.524 / Virus Database: 269.24.4/1476 - Release Date:
      5/31/2008 12:25 PM
      > >
      >
    • Fred
      Ted, if 40+ years is longer, well, perhaps yes and my HFN69 test disc has been well used since 1969 (and superseded of course). I also use HFS81 and Ortofon
      Message 111 of 111 , Jun 2, 2008
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        Ted, if 40+ years is longer, well, perhaps yes and my
        HFN69 test disc has been well used since 1969 (and
        superseded of course). I also use HFS81 and Ortofon
        Pick Up Test Record 0002. I've personally needed few
        test discs but am aware that the norm is to include
        those V/H tracks.

        Good point about minds but when people expend heavily
        on good gear and become aware of tweaks, a latent
        something strangely akin to engineers mindset can kick
        in.
        The "must" of betterment can drive the once
        non-technical to obsessions and acceptances beloved of
        snake oil merchants and the industry often benefits
        from repeat business and upgrades (and magazine
        readership)!

        A hobby and need perfectly suited to male displacement
        therapy? :-)

        Fred.



        --- Ted Rook <rooknrol@...> wrote:

        > Fred probably you have been doing this longer than I
        > have, it seems our experience of test
        > discs varies, I was pleased recently to discover
        > both types of test on the HFN disc 2 and I
        > stopped searching, was it more common previously?
        > Also perhaps I was speaking rather
        > loosely about vinyl users in general rather than
        > individuals here, don't you think that many are
        > uncurious about technical evaluation? That requires
        > the type of mind which engineers have
        > and that's not everyone.
        >
        > Ted
        >
        > On 2 Jun 2008 at 13:21, Fred wrote:
        >
        > > Ted,
        > >
        > > As a universally documented aspect of tonearm
        > > adjustment with almost every test record including
        > > both lateral and vertical resonance tests, why
        > would
        > > you infer that most people never give thought to
        > > vertical resonance?
        > >
        > > Fred.
        > >
        > >
        > >
        > > --- Ted Rook <rooknrol@...> wrote:
        > >
        > > > Thanks for the low mass arm recos Tom. I have a
        > > > pretty good grasp of tone arm and
        > > > cartridge dynamics but no motivation to put
        > energy
        > > > and money into a low mass unit at
        > > > present there are other priorities that come
        > first.
        > > >
        > > > I have to repeat myself here because I don't
        > think
        > > > the message is getting through. This is all
        > > > about LP records not CD. Tone arm resonance may
        > be
        > > > stimulated using test discs
        > > > specifically cut to activate either lateral or
        > > > vertical resonances. When most people talk about
        >
        > > > resonance they mean horizontal. In my system the
        > > > lateral resonance is fine, if anything a little
        > > > low at about 8Hz but not a problem, it is above
        > > > warp/wow and below the audio band, end of
        > > > story. The vertical resonance, which I supect
        > many
        > > > people may have never measured or
        > > > given any thought to is where the acoustic
        > coupling
        > > > becomes significant in my system. The
        > > > amp and speakers can reproduce everything
        > cleanly
        > > > all the way down to DC, there is no
        > > > problem with speakers or electronics, in fact
        > there
        > > > is no problem and I hope people realise
        > > > this, I am not looking for help here, I have a
        > neat
        > > > way of putting a high pass filter in the
        > > > system that suppresses the vertical resonance at
        > > > about 20Hz and prevents the low end from
        > > > being muddied. People are saying ah but the high
        > > > pass filter introduces phase shift. My
        > > > response is I can't hear it as a problem, it may
        > be
        > > > there but with LP source material I can't
        > > > hear it whereas I can the benefit of the
        > resonance
        > > > being supressed. A good compromise I
        > > > think.
        > > >
        > > > Regarding mistracking I'd like to find a way to
        > > > evaluate your claim about the stylus "bouncing
        > > > around" in the groove, I am persuaded otherwise
        > by
        > > > what I hear and measurements made
        > > > during antiskate adjustments. These measurements
        > > > quite clearly show this to be a linear
        > > > thing, harmonic distortion rises as the
        > antiskate is
        > > > reduced and reducing it further eventually
        > > > results in bursts of gross distortion. It is
        > > > avoidance of the gross bursts that is the aim of
        >
        > > > antiskate and it works. I'm operating in the
        > linear
        > > > controlled region, well away from the gross
        > > > bursts. I can believe that the gross distortion
        > if
        > > > allowed to occur would cause groove damage
        > > > but then I don't allow that to occur so I don't
        > have
        > > > any concerns about uncontrolled stylus
        > > > motion, it is audible and it is not happening in
        > my
        > > > system, there may be some who are new to
        > > > vinyl and would allow that to occur but I'm not
        > one
        > > > of them. So my concern with ordinary wear
        > > > remains the number one priority and at 1.25
        > grams
        > > > I'm at the upper limit of the
        > > > manufacturer's recommendation.
        > > >
        > > > Ted
        > > >
        > > >
        > > >
        > > >
        > > >
        > >
        > >
        > >
        > >
        >
        __________________________________________________________
        > > Sent from Yahoo! Mail.
        > > A Smarter Email
        > http://uk.docs.yahoo.com/nowyoucan.html
        > >
        > >
        > > ------------------------------------
        > >
        > > Yahoo! Groups Links
        > >
        > >
        > >
        > >
        > >
        > > --
        > > No virus found in this incoming message.
        > > Checked by AVG.
        > > Version: 7.5.524 / Virus Database: 269.24.4/1476 -
        > Release Date: 5/31/2008 12:25 PM
        > >
        >
        >
        >



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