My reference signal pass is 10KHz square wave with about a 10us rise-time. This is the best that I have found B&K 1/2" mikes can do, as well as 30ips analog magnetic recording. SACD or 24-96 or better should do something comparable, but so far, I have not found the sound comparable to the best vinyl. CD's simply will not meet this standard.
That square wave in the LP world is a sawtooth on the disk. The JVC system could cut with significant energy up to 80 KHz. And the best reproducer of that was the "strain gauge" Technics cartridge designed to do that.
There were a number of tape systems with the necessary phase equalizer to get square waves off the tape. Even then it was more of a "nice to have" than an essential requirement for audio.
A 10 KHz square wave will look a lot like a 10 KHz sine wave in a system with all harmonics above 20 KHz effectively removed. However, the next question; can you tell if its square or sine by ear alone?
There were a number of tape systems with the necessary phase equalizer to get square waves off the tape. Even then it was more of a "nice to have" than an essential requirement for audio.
A 10 KHz square wave will look a lot like a 10 KHz sine wave in a system with all harmonics above 20 KHz effectively removed. However, the next question; can you tell if its square or sine by ear alone?
Correct. See my earlier post.
And that is the rub. It would take an exceptional ear to detect the difference between a 7kHz square wave (the limit of 16/44 digital) and a 7kHz sine wave. It would be theoretically possible though.
10kHz "square" with 10us rise time and free of overshoot should be rather called a trapezoid. 10us rise time would reflect in about 35kHz(-3dB) roll off. So even the 3rd harmonic (30kHz), the first line in a spectrum above base frequency 10kHz, must be heavily degraded in amplitude to keep the square-like eye shape. It is rather the eye test than a sound test.
Re 10kHz sine vs. 10kHz square audibility, if anything is audible, than it is intermodulation or sub-harmonic in a speaker or in a human ear, which is non-linear enough to create its own distortion products.
PMA, I suspected a comeback from you. But everyone, think about it. What sort of rise-time can the human ear detect under virtually every circumstance? 20us? Kind of low, considering that with a simple -6 dB rolloff the amplitude level will be off by 3dB at 20KHz. What about 10us? It takes at least 35KHz with a simple -6dB rolloff, but REAL rolloffs are usually more complicated and in order to get an approximate 10us rise-time, you usually have to have 40K-50KHz, so that is my standard. I am talking about MUSICAL SOURCES, not an ideal test waveform. Some microphones can achieve this, some 30ips master recorders can as well, and finally 96KHz+ or SACD should be able to do this as well. MC phono systems can get close to this, using 1/2 speed recording or direct disc. Everything below this is a sonic compromise. We usually have to live with it, but it should not be our ultimate goal to compromise. When given a chance, I do not compromise, and the listening results have been gratifying.
I do remember back in my vinyl days, attempting to listen through the various imperfections of the medium to get to the emotional intent of the recording, so I think I know what you mean above, at least I hope I'm not completely off the beam.
But for me, this was never an enjoyable exercise, but rather a necessary chore; one which I was happy enough to leave behind. Not like the experience of an impressionist painting, for example. Or a partially-clad woman. 🙂
I misread the expression - actually, it represents the square of the speed of sound in biatomic gases. The "V" must stand for the specific volume, i.e. the density reciprocal.
The usual form of the speed of sound equation is (for diatomic gases):
Sqrt(1.4 X Gas constant X Abs. temperature).
In SI units, for dry air at a temperature of 25 Deg.C it would give:
Sqrt(1.4 X 287.05 X 298.15) = 346.15 m/sec.
Regards,
Braca
And, more importantly, to preserve excellent phase response. With a shallow roll-off, 100kHz or more may be required. At the low end, DC is desirable.
When I got tired of LP systems, I decided to make my own tape masters to enjoy. After considerable investment in time and money and learning to use microphones of various types and recording spaces -- etc....... The first sound immediately noticed is how clear the sound was compared to LP/cart/TT And, it was the treble that was so amazing and natural and extended which got my attention first. I never heard close mic'ed symbol treble so real like that on any LP system - ever. Maybe the 17DIII would come close today? I attributed the better sound from master tapes to be from lower distortions and extended HF response.
THx-RNMarsh
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Of course, the more bandwidth the better for best phase response, but I like to be realistic about my sources that were available even 40 years ago. Some, like 30ips analog recording, disc cutting, and even practical (quiet enough) microphones have not improved much in the last 40 years beyond my standard of 40-50KHz or approximately a 10us rise-time. Keeping to that is not easy, but I think necessary for ultra-reproduction of audio. It goes without question that you don't want to limit the bandwidth of the electronics to this standard, if possible, because each stage of the reproduction takes its toll, so even an adequate source can be compromised further down the line, including the tweeters.
Most here do not need to meet this criterion, I suspect, but I did give it to Dave Wilson, and he has been thankful to me for my efforts.
Most here do not need to meet this criterion, I suspect, but I did give it to Dave Wilson, and he has been thankful to me for my efforts.
There is a lot of room for creativity, between the master tape and the resulting vinyl record 😉. And let's not forget the nice vinyl adds like LF groove noise and thus very limited resolution.
I always recall my student practice in Supraphon recording studios, classical music recordings. What a huge difference between the master tape and the resulting vinyl. The vinyl sound was a caricature of the original tape sound. Do not understand who is still willing to praise the vinyl sound, I assume that only the people who mostly listen to a simple bar music or a single guitar music 😀. Or something like old rock. Sorry, complex classical music, symphonic orchestra is a proof.
Which is why I carefully specified direct to disk LPs for evaluation. The pinnacle of vinyl reproduction.
I was fortunate, in the early 1980s, to be asked to setup a system for a friend who was involved in the recording industry. He had a large collection of second generation master tapes (15ips, half track) and a beautiful Otari R-R machine to play them on. We compared Neil Diamond's Hot August Night (the recording we judged to be least messed around with by engineers, with realistic acoustics) on tape, vinyl and CD (through a Sony CDP101 and CDP701).
The results were unequivocal.
The tape was far and away the best, most accurate.
The vinyl was next.
Then, fair way back was the CDP701.
The CDP101 was unlistenable.
Yes, I would love to do the same test with a better CD player. My favourite is a Marantz CD80.
I agree that CD players in 1980's were mostly unlistenable, similarly the early digital recordings. However, both recordings of digital music and very nice SOTA DAC's have improved greatly from that times.
Any measurements? I've not seen anything to show the dynavector to be particularly special in the performance dept, but if there is something I would be intrigued to persue further.
Ref the CD80. My first CD player was a CD80. TBH I only miss it's ease of operation. Sonically IMO it has been so surpassed by newer stuff its not funny, but I do know that the TDA1541 crown has a legion of followers.
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