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RE: Is there a reference for the 6db thing? I can't find it

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In Reply to: RE: Is there a reference for the 6db thing? I can't find it posted by Tweaker456 on March 24, 2014 at 12:15:34

I think that you are confusing the point on the charts where they say the skin effect "starts" with the -3 dB point, They are NOT the same point!

The center of the wire has to be many skin depths below the surface before you reach the - 3 dB point, where the asymptote of the 6 dB (first order) roll-off is said to begin.

So when the chart says that 12 ga. has a skin depth corner of 4150 Hz, that is NOT the -3 dB point. The -3 dB point DUE TO SKIN EFFECT ALONE is much higher up, usually self-inductance causes a roll-off before the skin effect does.

A skin depth corner of 4150 Hz is the point where the skin effect starts to screw with the self-inductance, and the phase shift begins, and by many accounts, where the wire no longer faithfully passes musical _transients_ accurately.

Please note that steady state sine wave measurements are NOT going to provide the same info as a transient pulse in terms of where the problems start to crop up. This is another thing that Audioholics sorta ignores since it throws a wrench in their neat little world of single metric numbers and figures of merit.

I think that you are fixating on skin effect, when it is the sum total of all the cables materials, physics parameters, etc., that makes up the sonic signature of any given cable or pair of wires.

Jon Risch

Follow Ups:

RE: Is there a reference for the 6db thing? I can't find it - rkeman 17:35:29 03/26/14 (3)
Deleted.

Edits: 03/27/14 03/31/14
- RE: Is there a reference for the 6db thing? I can't find it - Jon Risch 21:00:47 03/27/14 (2)
  I think that you need to re-read what I wrote, rather than jumping to conclusions and setting up a straw-man based on said mis-understanding.
  
  Jon Risch
  - RE: Is there a reference for the 6db thing? I can't find it - rkeman 18:35:37 03/29/14 (1)
    Deleted.
    
    Edits: 03/29/14 03/31/14
    - RE: Is there a reference for the 6db thing? I can't find it - Jon Risch 21:31:03 03/30/14 (0)
      You apparently still did not re-read my post.
      
      Aside from that, regarding transients, a toneburst is one type of transient signal, but a very specialized one, and it is not necessarily what I was referring to.
      
      In the world of measurement signals (which doesn't always correlate directly or strongly to the world of listening to music), a single sample pulse (or dirac function), commonly used for FFT analysis, would be a type of transient more representative of musical transients, esp. cymbal crashes, electric guitar fuzztone spikes, etc.
      
      You don't mention if the toneburst you used was shaped or gated, this will have a significant impact on just how "transient" it is in terms of a test signal, even so, the primary toneburst frequency would still tend to mask or overshadow the true transient portion of the toneburst, if it were not a shaped type.
      
      In terms of showing energy storage, yes, a tone burst can do that for the loudspeaker, primarily AT THE GIVEN FREQUENCY of the toneburst. Away from that frequency, the measurement equipment will be unable to discern the transient behavior of the DUT, unless it is truly terrible and of a large amount of deviation from linearity.
      
      Finally, there is a significant difference between an energy storage resonance (which is what toneburst's measure with a loudspeaker transducer), and other effects that tend to blunt or soften a transient, which is more of a filtering effect. Signals that work well with the former, will not be very effective with detecting the latter.
      
      Previous posts referred to the likely effects more specifically, they did not refer to energy storage issues.
      
      So the bottom line is, your jumping in here with comments about measuring tonebursts is a complete red herring, and really bears no relationship to what was being discussed.
      
      With that in mind, I strongly suggest you give it a rest, and beat a strategic retreat.
      
      Jon Risch
RE: Is there a reference for the 6db thing? I can't find it - Duster 14:57:43 03/26/14 (0)
IMHO, the way audible skin effect alters transients due to phase shift may be even more pronounced than high frequency roll-off.

Some folks may consider a softening of the leading edges to be somewhat euphonic or "smoother" while obtaining a bolder sounding sonic signature, especially in an otherwise edgy sounding system.

just my 2 pennies

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