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Question for the JAs

142.79.101.139

Posted on January 9, 2021 at 08:57:42
E-Stat
Audiophile

Posts: 37460
Joined: May 12, 2000
Contributor
  Since:
April 5, 2002
Given Stereophile's long standing heritage of using a wide range of measurements, I would like to get your take on an assertion advanced on another audio board by an ex-submariner.

I confess that while measurements are valuable to an extent, I find they fail to be able to make subtle determinations such as the ability to recreate natural hall ambience. Like what John observes when using his own minimally miked recordings as a reference. Response by the Chief?

And to your how it looks question... it's a time v frequency waterfall display, easy day

When pressed, his reply was:

Sorry, I was not aware that you are also familiar with the capabilities of the equipment the Office of Naval Intelligence uses to analyze sound.

While I have no doubt the Navy possesses pretty sophisticated ways to analyze the kinds of sounds important to track other ships, have they mastered something no one else in the audio industry understands? I'm aware of waterfall metrics found with speaker tests, but are they also sensitive to conveying the performance of everything upstream?

 

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Waterfall plots, posted on January 9, 2021 at 09:31:37
Jim Austin
Reviewer

Posts: 71
Location: New York
Joined: March 11, 2019
I'm aware of waterfall metrics found with speaker tests, but are they also sensitive to conveying the performance of everything upstream?


My first thought is that in a submarine context, waterfalls are best avoided. ;-)

This is all rather cryptic, so it's hard to reply in detail or with confidence. A waterfall plot is merely a way of displaying certain kinds of data. In audio, it's usually used to show energy (or a comparable parameter) as a function of frequency and time. It is used in different contexts: delayed energy in a loudspeaker cabinet, room reverberation (and stored/released energy in the room), etc. Does it reflect everything upstream?

What, upstream, has similar behavior? A transformer core, perhaps? I can't think of any upstream phenomena that would be well-displayed in a waterfall plot.

In any case, I believe that delayed energy at the end of the chain--in the loudspeaker--drivers and cabinet--and in the room (reverberation and energy storage in floors, walls, windows, etc.)--will swamp what comes before, since the time scales are longer and the amount of energy involved is larger. (Swamping is another thing one wants to avoid in a submarine.)

A vague answer to a vague question.

Best Wishes,

Jim Austin, Editor
Stereophile

 

Thanks for the response!, posted on January 9, 2021 at 09:42:07
E-Stat
Audiophile

Posts: 37460
Joined: May 12, 2000
Contributor
  Since:
April 5, 2002
My first thought is that in a submarine context, waterfalls are best avoided. ;-)

Agreed!

I can't think of any upstream phenomena that would be well-displayed in a waterfall plot.

That is my reaction to the Chief's smug response.

In terms of conveying subtleties of hall characteristics and ambience, I find that everything upstream makes a difference. Even with the modest garage system, I've found that replacing the TI op amps with Burson FETs in the DAC and using a battery supply in lieu of a SMPS in the streamer make noticeable difference in conveying those characteristics.

 

RE: Thanks for the response!, posted on January 9, 2021 at 09:46:38
Jim Austin
Reviewer

Posts: 71
Location: New York
Joined: March 11, 2019
In terms of conveying subtleties of hall characteristics and ambience, I find that everything upstream makes a difference.


Perhaps so. Although the sense of ambience can be affected by many factors, including frequency response, loudspeaker directionality, and so on, at its purest, such things being equal, it's about information retrieval.

Jim Austin, Editor
Stereophile

 

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