AES Damn Lies Workshop

This is a video version of my workshop "Lies, Damn Lies, and Audio Gear Specs" from the October 2013 AES show in New York City. Panelists are Ethan Winer, Mike Rivers, Scott Dorsey, and David Moran. This video explains how the fidelity of audio equipment is assessed and measured, and is an offshoot of my book The Audio Expert:

Questions and discussions about this video are welcome at my Audio Expert forum:

Also mentioned in this video:

AES Audio Myths video from 2009:

The library section at the Rane web site:

David Moran's PDF file that explains loudspeakers:

The acoustic product testing article on my company's web site:

Not mentioned in this video, here's an expanded explanation about slew rate:

Here's a newer article that explains jitter in more detail, with a video that lets you hear different controlled amounts of jitter:

[jozefserf]

If there were any worthwhile awards for contributions to truth and understanding in audio, then Ethan Winer should indeed be at the head of the queue.

He's not in this to separate you from your money or even to make friends.
Respect.

[learnerlearns]

This is just incredible! The amount of knowledge, research, writing, editing, narration, audio and visual references... Holy crap how much effort and experience went into this!>!?!?

There needs to be some kind of Nobel peace prize for truth in audio.
I nominate Ethan Winer.

[ODWALLA]

Excellent.Thanks for assembling the data and making it available.

[AaronAntko]

just when I start thinking Im getting a grasp on a concept someone goes and 180's it :). thanks for all well laid out information that redirected me correctly. People like you make learning much less stress full. Thanks.

[windwardpro]

Extremely well presented- with excellent narration, graphics, and information, and covering a lot of important ground.

[MichelLinschoten]

Well the reason why companies do not touch any of this...

Simple....the actual truth does not sell 3000usd cables and 12000 usd amplifiers. Audio is these days a business model, and a very successful one.

[LasseHuhtala]

Thank you Ethan & Co. This video was most appreciated.

[Maxxa]

Very impressed at the wealth of information and effort put into this.
Many thanks to the guy who made this video.

[sarsedacn]

respect Ethan. I value how sincere you are in demystifying the subject matter. thank you

[tdw]

Very helpful primer for the audio enthusiast!! Thank you for your efforts!

[colinmiller]

This is a great comprehensive video Ethan! Thanks for making it!

[fredygump]

I learned a bunch of things that I wasn't sure about before. Thanks.

[gamerpaddy]

the high damping factor values are due to how much negative feedback the amp has. it actively steers against the back emf instead of just relying on output impedance

[ronaldgarrison]

An excellent and very informative video. A few things to add:

1. Two forms of inaccuracy not mentioned here, at least not directly: modulation noise, and phase shift. Phase shift comes under the rubric of frequency response, but must be specified separately from the amplitude response. (Exception: If you can positively assure that the whole system is minimum-phase, then in theory knowing the amplitude response gives the phase response. However, even then, small amplitude errors could lead to larger phase errors, and the reverse as well.)

2. Modulation noise usually tends to cluster right near the original signal in the frequency domain, so instruments designed to measure THD and IM won't pick it up, with the usual methods. (OTOH that same proximity tends to mask its audibility.)

3. Has the audibility of phase distortion finally been characterized clearly. Decades ago, it seemed there were thousands of papers on this subject, with each presumably claimed to shed new light on the subject.

4. Slew rate may be a relevant measurement for line-level analog circuits, but for power amps, power bandwidth seems to show what's going on more clearly.

5. Many claims have been made about less negative feedback being better on account of better handling of high-frequency, high-power signals. I could never understand that. You either have the necessary power bandwidth or you don't, and feedback or the lack of it doesn't change that, as far as I can see.

6. Objective measurements (using the usual parameters) can indeed tell you how accurately a device reproduces sound, but the problem is that the amount of data can become huge. And as you indicate, when it comes to mics and speakers, the data can even go beyond three dimensions, as you account for level, frequency, and direction, just to start with. Computers are a big help with this, but of course, using them to good effect is not always a trivial matter.

[sankstone]

Thank you Ethan for sharing. Great over my head but I did learn a few things. There is hope for my puny little studio with less than very expensive gear. 

[basspig]

Excellent and clear presentation. I know you weren't here for the last workshop I presented on TIM distortion, but I want to mention that there is a third, more effective test for TIM that was developed by Robert R. Cordell at Bell Labs. It uses three tones and meets these qualifications: (1) inexpensive lnstrumentation, (2) simple measurement procedure, (3) good sensitivity (particularly to midband even- and
odd-order IM products), (4) in-band stimulus and response, (5) good subjective correlation due to music-like test signal risetimes. I set up this demonstration at my last B.A.S.S. workshop in April, which, unfortunately coincided with an AES event in NYC that weekend, so you were unable to attend.

[studiosingyourstyle]

I would love to have you step in my space and do a video explaining all the problems … so fascinating!!!

[musicstevecom]

GREAT Video, I will have to watch it many times, I'm looking at the "Analog Discovery 2" its computer based software and its does more than a digital scope (its based on a Built in sound Card) after searching the web I think this it the best for me instead of the old testing Equipment (E-bay) which is very good but old. The Analog Discovery 2 is growing and they "Digilent" will keep updating the software and I hope it will be around for a while, what do you think of Digilent.-Analog Discovery 2 ????

[duvignau]

This is a great review!!! Thank you Mr. Ethan!

[elblopex]

5:49 this might be the most important and valuable statement I've ever heard