No, it isn't. It is a field, discipline, science or art, depending on your point of view.
But as to your statement that there is something to hear above 20 kHz, it is only true in the narrow sense that there might be some signal content above 20 kHz in "hi-res" or upsampled material - but it can't be directly heard. So it is there to be heard, for bats and dogs, but normal humans can not hear it.
Any references to support that claim?
I agree that humans can hear signals caused by source signals that go up to 40 kHz if it is played at such extremely high levels that there is distortion and intermodulation products at audible frequencies.
I agree when put like this. 🙂
"Heard" is not the correct word. But signals above 20khz* impact the perception of sound under 20khz therefore can be "heard".
There isn't much literature (close to 0) because of the interest about compression rather than improving sound reproduction in the last 30 years.
I have mostly to rely on my rather unscientifical empiric testings.
I aim for at least 30khz clean, 50k better.
*i dont believe in the gigahertz crap of that ultratweeter that Stig linked, but to waves up to ~300khz).
Edit: Now all this matters because of the behavior of Ncores towards very high frequency. I'm planning to build mines (hehe), but they are not going to power the HF ways. Maybe next version will have a switching frequency in the megahertz region, so that i could live without heavy and inefficient class A amps 🙂
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Well....
I agree it would be interesting to hear some class D designs with much higher switching frequency, but current MOSFETs do not allow this. Until there is a major breakthrough in semiconductors, much higher switching frequencies will not be possible.
I agree it would be interesting to hear some class D designs with much higher switching frequency, but current MOSFETs do not allow this. Until there is a major breakthrough in semiconductors, much higher switching frequencies will not be possible.
There are plenty of RF semiconductors, but probably they don't have the current capabilities needed for class D design.
SiC seems to be improving. So 3+ years from now, who knows? 🙂
Yeah...
Certainly the semi developers are working on this hard, as SMPS efficiency goes up with higher switching speed and lower switching losses… there is a lot of money to be made.
Certainly the semi developers are working on this hard, as SMPS efficiency goes up with higher switching speed and lower switching losses… there is a lot of money to be made.
I remember Bruno said a few hundred pages ago that he could increase the bandwidth of the Ncore, but that would degrade the audio-band performance.
Not sure I agree with that - yes, a fair bit of practical engineering has been directed at better compression algorithms, but at the same time a fair bit of pure science has been going on looking into the neuroscience of hearing.
Depends on how you define "clean". Is "clean" response within +-3 dB? Or an absolute upper limit at least 2 * higher? Or something else?
Well, I have some RF amplifiers you could use 🙂 How does 150W@500MHz sound? Not that I would use them for audio...
-3dB at 30khz is fine, including also the eventual amplifier rolloff.
With clean i meant two things:
*perfect 15khz squarewave
*no dithering/aliasing artifacts up to 30khz (better 50)
anytime the HF debate comes up, I can't help but remember that most of the audio catalog available today is in a format that can't hold any audio info past 22kHz. last time I checked, oversampling can't "reinvent" the information that has been low-pass filtered at the recording side in order prevent aliasing.
I've read many positive reports about super-tweeters. funnily, the latest I can remember came from a guy that used RedBook. talk about credibility...
I've read many positive reports about super-tweeters. funnily, the latest I can remember came from a guy that used RedBook. talk about credibility...
-3 dB at 30kHz will not give you "perfect" 15kHz squarewave.... not at all. You'll need bandwidth far into the MHz range for that.
Why? Nobody listens to 15 kHz square waves.
Again why? if you can't hear those artifacts, all you need to do is make sure they don't cause any intermodulation or distortion.
I guess he meant perfect as in as much as the scope's display allows, given certain timebase 😀
Well, to be precise, to get perfect square waves you need unlimited bandwidth. Hmm... Maybe there is a need for terahertz amps...
"These claims are being made by people with cheap scopes with limited resolution" 🙂
quite possible.
personally I have such varied musical tastes that I can't imagine myself in that position. music can deliver such a wide range of emotions that I find sticking to certain genres/time windows very restrictive in that regard. but I digress.
well...
I raise you a tuvan throat singer accompanied by 3 mustaphas 3 and one fake cuban conjunto doing kraftwerk covers...
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