They create distortion, their regulation is redundant when one already has voltage regulators following the circuit, and they are physically noisy. For some industrial applications they are just fine. I had a 1400W unit myself, once.
Heard an interesting presentation by David Greisinger just now at the AES.
Subject is how can we determine not just direction but also position/range of a sound source in the presence of many similar sources. Example: two string instruments that produce same pitches and harmonics at two different angular positions but still we can hear them separately.
Not sure I understand any and all points but it appears to involve the phase shift between the harmonics of a particular source. In other words, even if two sources have the same harmonic structure we still can discriminate between them and focus on each separately, using the phase relationship between the harmonics. If the phase relationship between the harmonics remains intact we can determine position/range even with other similar interfering sources.
When you have a reverberant venue, at a certain point in time the phase relations start to smear and you can't locate the source anymore. That is one reason why location gets difficult with reverberation sound arriving very close after the direct sound, but not if there is enough time between direct and reverb sound for the brain to do its location processing.
Might that have some relation to why some amps that measure identical to other amps, nevertheless have better soundstage and localization? Because they better preserve the phase relation between the harmonics in the distortion products?
Thoughts?
jan didden
Subject is how can we determine not just direction but also position/range of a sound source in the presence of many similar sources. Example: two string instruments that produce same pitches and harmonics at two different angular positions but still we can hear them separately.
Not sure I understand any and all points but it appears to involve the phase shift between the harmonics of a particular source. In other words, even if two sources have the same harmonic structure we still can discriminate between them and focus on each separately, using the phase relationship between the harmonics. If the phase relationship between the harmonics remains intact we can determine position/range even with other similar interfering sources.
When you have a reverberant venue, at a certain point in time the phase relations start to smear and you can't locate the source anymore. That is one reason why location gets difficult with reverberation sound arriving very close after the direct sound, but not if there is enough time between direct and reverb sound for the brain to do its location processing.
Might that have some relation to why some amps that measure identical to other amps, nevertheless have better soundstage and localization? Because they better preserve the phase relation between the harmonics in the distortion products?
Thoughts?
jan didden
You want a copy of "The Psychology of Music" 2nd edition,
edited by Diana Deutsch. There is some excellent material
regarding grouping mechanisms (aka binding), particularly
ch. 9.
😎
edited by Diana Deutsch. There is some excellent material
regarding grouping mechanisms (aka binding), particularly
ch. 9.
😎
It is a textbook. So the price is high because most purchasers are required to buy it. However as the major book in the field almost every major university library has a copy.
If buying online do not confuse it with the 1938 book of the same title but different author.
A bit cheaper is Bregman if this stuff captivates you (it does me). I've recently acquired this but not delved into it yet.
Amazon.com: Auditory Scene Analysis: The Perceptual Organization of Sound (9780262521956): Albert S. Bregman: Books
I would also endorse the Al Bregman book in favor of the other.
Although parts of it are bit dated now, he was an important and capable contributer to the field. As far as the David Greisinger work goes, at this point I would not get too excited about it.
My colleague, Ron Quan has his give his paper:'New Techniques for Evaluating Audio Amplifiers via Measuring for Induced Wow and Flutter and Differential Phase Distortions'.
Works for me.
Works for me.
Wow and flutter are mechanical terms and make no sense in the context of purely electrical measurements.
Nope, I stand pat on this. Using the terms wow and flutter in a purely electrical stimulous/measurment context is just sensationalism, typical of the poor rigor of the AES peer review process.
Sure it does. Wow and flutter is FM added to tape by speed irregularities. FM meters were developed many decades ago to measure this. Were is yours?
The accepted definition of wow is <4Hz frequency wander, i.e. 60Hz and 3000Hz don't make wow no how.
BTW Wikip is out to lunch again, jitter is not wow and flutter. Check the discussion page on emitter follower. There is a long running argument of weather emitter degeneration is feedback.🙁
BTW Wikip is out to lunch again, jitter is not wow and flutter. Check the discussion page on emitter follower. There is a long running argument of weather emitter degeneration is feedback.🙁
It doesn't prevent using the phenomena of wow in other frequencies, for other purposes.
Obviously Scott objects to the language used. But is there substance underneath the less than academically perfect description? Can anyone explain in clear terms what Ron's position, arguments and measurements are? I'll have access to the paper in a week or two but not yet. I missed the presentation so I don't know any details.
- Status
- Not open for further replies.