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Volume level matching !

Discussion in 'trade discussion' started by Purité Audio, Feb 9, 2017.

  1. Purité Audio

    Purité Audio Trade: Purite Audio

    Want to compare those two audio components without prejudice!
    Level matched and unsighted comparisons , remove all bias here's how...

    http://www.puriteaudio.co.uk/blog

    Keith
     
  2. G T Audio

    G T Audio Trade: Distributor and Manufacturer

    What's wrong using your ears and turning the volume up or down? Its not rocket science Keith if you know what you are doing...
     
  3. Purité Audio

    Purité Audio Trade: Purite Audio

    Which you clearly don't.
    Keith
     
  4. Tony L

    Tony L Administrator

    <moderating>

    I'll move this to Trade Discussion so non-Trade folk can comment as it isn't a Trade Announcement by any stretch. If it turns into any kind of slagging match, as the above post implies it may, it will be moderated good and hard!
     
  5. G T Audio

    G T Audio Trade: Distributor and Manufacturer

    If you can't hear the difference in level and want to clarify this you can always play a test tone [about 1kHz] from a test CD, vinyl test record or if you have this on a digital file through the system. Then you can use a sound level meter like this one from Maplin at the listening position to adjust the level accordingly on your amplifier to match levels.

    There is probably an app you can download off the web that would allow you to perform the same operation using your phone...
     
  6. Purité Audio

    Purité Audio Trade: Purite Audio

    Level matching should be to .1dB.
    Measuring the output is the correct and accurate method.

    Keith
     
  7. G T Audio

    G T Audio Trade: Distributor and Manufacturer

    Keith, do you realise that the "just noticeable difference" in level the human ear can detect is between 0.5dB and 1dB! Some humans can only detect a 0.5dB difference in level if they have extremely good sensitivity to sound but this is rare. Typically the average human can just about detect about 1dB to 1.5dB difference in level.

    You might find this useful.
     
  8. topoxforddoc

    topoxforddoc pfm Member

    If you are comparing output from different digital or analogue tape sources, you can do this with calibrated test tones and PPM (NOT VU) meters (plus a XLR to RCA converter such as an Alice Matchpak, where the XLR-RCA levels can be adjusted to suit).

    The BBC would line up their broadcast machines at 0dBU level (i.e. PPM 4, -4dB on VU or -18dBFS on digital). This is called "Zero Level". If you align all your machines to Zero Level, then the output will be the same.

    https://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP202.pdf

    In the days when the BBC used analogue tape machines, these were checked and aligned on a daily basis. The BBC would accept aligning playback levels to +/- 1 db and record levels to +/- 0.5 dB (No need for +/- 0.1 dB as that is a) unnecessary and b) undetectable by the human ear).

    https://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP202.pdf
     
  9. badger748

    badger748 pfm Member

    So if you get it measured absolutely perfectly within 0.1 dB, does this mean you have to sit bolt upright and never move your head even one degree left or right, other wise that exact measurement is pointless?
    Where do you draw the line - laser measurement sitting on the sofa? Head rigid.
    Surely the who point of Music (remember that?!) is to ENJOY.
    Get it "there or there abouts", glass of wine, comfy chair, volume up - listen and love.
    Just sayin' ......
     
  10. Purité Audio

    Purité Audio Trade: Purite Audio

    You might want to look at this Graham, slightly more recent .
    F.E. Toole and S. Olive, "The Modification of Timbre by Resonances: Perception and Measurements", JAES vol 36, # 3, March 1988, pp 122-142

    The point is the brain that the brain is extremely powerful and if you really want to compare two components without bias, then the need to be level matched, ( measuring the output of the device is the most accurate) and compared unsighted.
    Keith
     
  11. Tony L

    Tony L Administrator

    For most of us this kind of OCD is either impossible or pointless anyway. As an example I use a stepped attenuator and the finest steps are 0.5db (which is far more precise than most). As such that is the finest adjustment I could make. Does it matter? No, of course not, as I, like I suspect most sane audiophiles, make my mind up on something over a period of weeks if not months. Fast AB dems are of very little use to anyone but salesmen IME, and in that scenario then watching the levels is certainly useful. For the rest of us auditioning at home or deciding whether to keep or flip a recent second hand purchase they are of far less use. Try the new thing for a week or two, if you are enjoying listening to music more it is better, if not it is worse. It really is that simple!
     
  12. Robert

    Robert Tapehead

    Level matching is important if you want to minimise or eliminate an important factor not related to actual, qualitative differences between components. This has been proven so many times over decades that it really shouldn't be contentious any more.

    How far you take these things is entirely up to you, the listener, and what hinges on the result of the listing comparison.

    Not everyone has the equipment or inclination to match down to 0.1dB, but some attempt to match levels such that a perceptible level difference doesn''t exist costs nothing but a few seconds and at least minimises a known influence.

    Most people of course make no attempt to level match whatsoever, and will even attempt to draw meaningful conclusions when comparing equipment in different locations at different times!
    This is why perhaps 95% of subjective comment about audio equipment is quite frankly, nonsense.

    I would go further and suggest that audible differences often don't exist between boxes of audio electronics, and that reported differences are actually the result of the poor comparative listening practices.

    Unfortunately, lack of proper listening controls are essential to the practice of many manufacturers and dealers selling people new, improved, upgraded, tweaked, special edition, equipment which performs much the same as the preceding generations of equipment. So we should not attempt to persuade the industry to change tack on this issue, but those individuals wanting to improve the reliability of comparative listening can benefit form a little extra care taken to reduce bias.
     
  13. Mike42

    Mike42 Heard it all before...

    If product A sounds a bit better than product B when its a bit louder then buy product A and turn it up.
    If loudness was the only important consideration then we'd all get amplifiers that go to 11...
     
  14. flatpopely

    flatpopely Prog Rock/Moderator

    And yet when I did a level matched AB with a NAIT and 72/135 and the differences were easy to hear.
     
  15. Purité Audio

    Purité Audio Trade: Purite Audio

    If one of the amplifiers is incapable of properly driving the loudspeaker then you could hear a difference.
    Keith
     
  16. flatpopely

    flatpopely Prog Rock/Moderator

    Both amps were testing using a scope to ensure level matching and no distortion.
     
  17. Purité Audio

    Purité Audio Trade: Purite Audio

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