This has been done to ensure accuracy during single tone testing.The other question you raised is interesting. It occurs to me that signal processing could be used to nullify distortion, if the distortion characteristics of the drivers are very will understood.
amen
I do find it interesting/comforting that two of the leading researchers in psychoacoustics essentially say “meh” about distortion. Especially since Geddes spent so many years researching it and coming up with a very high correlating metric for it. (Geddes’ chat is below for this who missed it)
Over the years I have found that compression is more important and tends to be what I hear when I hear problems that aren’t otherwise linked to. Take, for example, the Klipsch Fives powered speaker with a built in limiter that I have reviewed. It has relatively medium distortion in the LMF. But it also has a lot of limiting. 2dB or more even in the lower midrange to Midbass. What did I hear? The limiting, by far. And this was well before I had a clue that such a limiter was built in.
IOW, compression is far more important to me than distortion. Namely because it directly shows up in frequency response as a linear non-linearity. We all know the impact of FR. And that jives with what Geddes told me when we had our chat.
that said, I will continue to provide HD results since it’s so easy to generate as well as IMD/Multitone for transducers in hopes that one day it can be useful in some way. But it isn’t anything I feel is a necessity as I do about compression/limiting.
Chat with Dr. Earl Geddes of GedLee Audio
Beam control has been implemented in combination with wavefield synthesis to achieve just this kind of control at audio frequencies: https://www.audiosciencereview.com/forum/index.php?threads/holoplot-x1-matrix-array.23186/ I believe in one demonstration they also used parabolic mirrors to control perceived direction as well.What is potentially realistic and potentially done in some sound bars is the use of DSP to implement different phase shifts for the individual drivers, to compensate for the varying distances from the listener to the individual drivers. Said differently, by varying the phase for the individual drivers, it may be possible to make the forward-radiating beam spread out wider. I wrote "may be possible" because I'm not at all certain this is possible. If you think about phased-array radar, differential phase shifts applied individually to the individual radiating elements makes it possible to steer the beam. But the narrow directivity of the beam is due inherently to the overall dimension of the array compared to the wavelength, and also due to the nature of electromagnetic radiation. There are speakers nowadays that use multiple tweeters in an array, the implication being that it is possible to control the beam width by controlling the phase offsets among the individual drivers. I have decided whether I believe this is believable. Even the ability to steer the beam in a phased-array radar is possible because there is just one wavelength. For a given, specific wavelength, it is not difficult to see how relative phase of different radiating elements could be used to steer the beam, and if this can be done to steer the beam, maybe it is possible to steer the beam to the right from the elements on the right and to the left from the elements on the left. Maybe. And maybe it is possible to do this sort of thing even for wavelengths covering a range of an order of magnitude or greater.
I'm also a little puzzled by the distinction between distortion and compression (or by drawing a distinction between a driver's distortion and its linear excursion range). Non-linear distortion implies the presence of spectral content not present in the test signal, which occurs when the signal is misshapen, i.e., when a perfect sinusoidal looks almost like a perfect sinusoid but it is little bit flattened at the top. The misshapen waveform contains spectral content in addition to the original pure tone(s). It seems to me that this isn't inherently different from what occurs with compression.
Captions help people who are hearing-impaired, and generally.Or, you can just watch the damn video without complaining about it.
Captions help people who are hearing-impaired, and generally.
Yes, I know this is an audio-focused forum, doesn't matter.
For sure, I saw the smiley!i get it. It was tongue in cheek.
But I don’t have the time to make a transcript. Someone else already did, though.
Both technologies you mention have been implemented to commercial soundbars, for example the driver distortion reduction by precompensating the signal appropriately (of course with obvious limitations) at some recent Samsung modelsThe other question you raised is interesting. It occurs to me that signal processing could be used to nullify distortion, if the distortion characteristics of the drivers are very will understood. But only up to a limit, and the limit is probably fairly tight. The problem is that the idea suggests that it would be possible to get unlimited volume from an arbitrarily small speaker by nullifying the distortion. Intuition is sufficient to realize that this is not possible, and from this it follows that the ability to do this kind of thing successfully would be limited to a very small increase in the volume level that can be achieved before the distortion becomes intolerable. The question is only what that small increase in volume would be exactly. 3 dB? 6 dB? When you consider how much greater the excursion of a speaker diaphragm has to be, for a doubling of power (+3 db), I think that the improvement that is inherently possible is probably not greater than 3 dB.
What is potentially realistic and potentially done in some sound bars is the use of DSP to implement different phase shifts for the individual drivers, to compensate for the varying distances from the listener to the individual drivers. Said differently, by varying the phase for the individual drivers, it may be possible to make the forward-radiating beam spread out wider. I wrote "may be possible" because I'm not at all certain this is possible. If you think about phased-array radar, differential phase shifts applied individually to the individual radiating elements makes it possible to steer the beam. But the narrow directivity of the beam is due inherently to the overall dimension of the array compared to the wavelength, and also due to the nature of electromagnetic radiation. There are speakers nowadays that use multiple tweeters in an array, the implication being that it is possible to control the beam width by controlling the phase offsets among the individual drivers. I have decided whether I believe this is believable. Even the ability to steer the beam in a phased-array radar is possible because there is just one wavelength. For a given, specific wavelength, it is not difficult to see how relative phase of different radiating elements could be used to steer the beam, and if this can be done to steer the beam, maybe it is possible to steer the beam to the right from the elements on the right and to the left from the elements on the left. Maybe. And maybe it is possible to do this sort of thing even for wavelengths covering a range of an order of magnitude or greater.
For you maybe, not for me.I wish a transcript of many of these videos was available. It's so much faster to read than to watch.
Correct.For sure, I saw the smiley!
The suggestion from MZKM was to turn on auto-caption, which I didn't think of, but was a good idea (assuming it works of course, I have no experience posting to YouTube). Also assuming all you have to do is enable a function, not type a transcript.
I downloaded the transcript NTK generated. Not too bad.
For sure, I saw the smiley!
The suggestion from MZKM was to turn on auto-caption, which I didn't think of, but was a good idea (assuming it works of course, I have no experience posting to YouTube). Also assuming all you have to do is enable a function, not type a transcript.
I downloaded the transcript NTK generated. Not too bad.
I think it is in the process of generating it. YouTube states long videos won’t have them, but your ~2hr video with Christian and your ~1hr video with Earl has them. However, your video with Lars doesn’t (it’s like 3min longer than the one with Christian).Nope. No auto-captions available, at least not yet. Sometimes YT generates them and sometimes it doesn't.
I think it is in the process of generating it.
Indeed. The posts were informative though. I now know more about a process I was only dimly aware of previously. As is often the case, ASR forum tangents deliver.Hence the "... at least not yet".
So many posts about captions. You just gotta wait it out. Patience is a virtue.
IIRC during one of his talks @j_j (pretty sure it was him, apologies if not) shared a story about setting up a PA for a party in his youth, and the crowd was asking to turn up the volume despite the system being at its limits. So he inserted a germanium diode into the circuit to increase the effective distortion. Although the output power didn't change, the spectrum did, due to nonlinearity, and the crowd was satisfied.
From my perspective, from reading and thinking about what I've heard myself, nonlinear distortion seems to have its primary effect on perceived loudness, with secondary effects on pitch and roughness when gross.
Geddes' comments on group delay were interesting but the only good research I know of is by Blauert from the late 70s, which gives audibility thresholds at 2 cycles or so, with some variation across the audible range. How this becomes an increase in perceived loudness I don't know.
PA's are a whole different game where a lot might be going on:Is this the primary cause for listener's fatigue as well? Subjectively, I find sound of most PA systems I heard over the years very fatiguing, and I always thought it was because of too much SPL.
That might lead to a sound made to cut through everything.