This is not possible in an analogue system. It may happen in some digital systems, depending on the type of filters used.mmerrill99 said:
Yes, the amp doesn't know and doesn't care that the input will turn out to be a sine wave.PMA said:
You (and HvM) cannot have it both ways. Either your impedance compensation affects the output voltage of the amp+cable (in which case it is not a voltage source) or it does not (in which case it can have no effect). Why not make sentences and paragraphs which have meaning, within the context of electronic engineering, rather than inventing your own language?Joe Rasmussen said:
I am going to guess that Joe sees himself in the "progressive" group while I am guilty of "extreme conservatism". If by that he means people who believe that Kirchoff, Ohm etc. were right all along then I guess I have to plead gulty. "Progressives" don't have to suffer from all this repression and are free to invent new words, new meanings for old words and, when necessary, new physics. The sad thing is that much of this creativity actually passes them by, because when inventing new meanings or new physics they often don't realise that this is what they are doing because they are not sufficiently familiar with the old meanings and the old physics.Joe Rasmussen said:
I hope you aren't disappointed by all the technical/theory stuff that's bandied about
(in response to Markw4) No, don't flatter yourself, you have your own unique way of misbehaving
Actually, I like all the technical+theory stuff, that’s why I persevered coming here, only I find the internecine warfare between rival factions unnecessary and at times very distressing, especially when finding myself dragged into it. I have since drawn a line under that aspect of my personal behaviour. Frankly, I could sit at the feet of DF96, John Curl, and R N Marsh and listen to them as the holy trinity of electronic engineering all day long.
As you for you Markw4 ....... being told that I have contributed nothing to diyAudio actually tipped me over into the abyss of clinical depression for three days before I realised my own self worth again. Look through my postings and you will see I have contributed in a myriad of ways beyond you. All you do is tell other people what can’t be done and what not to do. You are not my dad, and I can assure you there is more to life than wearing starched white chinos.
And I do love all the crazy stuff, too.
ToS
Demian’s triband test file, adapted for 44.1kHz sampling rate systems and 64k FFT length testing, no window function.
(mono wav, 44.1kHz/24bit, 1min long)
Dropbox - L+M+H (-6dB_44.1kHz-24bit).wav - Simplify your life
(mono wav, 44.1kHz/16bit, 1min long)
Dropbox - ditheredL+M+H (-6dB_44.1kHz-16bit).wav - Simplify your life
Freq:
100.264, 116.414, 135.255, 156.789
987.163, 1245.561, 1571.251, 1983.073
6764.790, 7618.716, 8579.636, 9662.352
George
(mono wav, 44.1kHz/24bit, 1min long)
Dropbox - L+M+H (-6dB_44.1kHz-24bit).wav - Simplify your life
(mono wav, 44.1kHz/16bit, 1min long)
Dropbox - ditheredL+M+H (-6dB_44.1kHz-16bit).wav - Simplify your life
Freq:
100.264, 116.414, 135.255, 156.789
987.163, 1245.561, 1571.251, 1983.073
6764.790, 7618.716, 8579.636, 9662.352
George
Attachments
You are very easily misunderstandable because you use technical terms in weird combinations, for one thing.
So, let me quote from your post I allegedly just skimmed:
On quick count, there are at least 6 things wrong in what you are writing here. Since you packed these untruths in just 4 sentences, this ought to be regarded as quite an accomplishment.
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You continue to take any criticism of your ideas as a personal attack. Maybe Mark can comment, do you think this is true of the Benchmark amplifier or better yet do you think it would fail its distortion specs into an 8 Ohm load at 40 degrees of phase?
Doesn't seem Joe and you are necessarily defining 'distorted current' in the same way. Could be Joe is simply defining it as a current with waveform other than the exact same shape as the voltage waveform being output by an amp. It's not clear what he means since he uses his own language to describe things. If his language were close enough maybe he could be understood, but its so different as to be gibberish for me.
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Yea, I know what you mean - only digital filters can pre-ring but I guess when modulated noise is mixed in with the attack portion of a sound, it can alter the perceived timing of that sound - that was really what I was trying to say
Of course it 'doesn't know and doesn't care' but that doesn't mean a sine wave exercises the system in the same way as music does - we see the example of dual tones & multitones that show up IMD which a single tone going from +Vp to -Vp doesn't. I'm also asking if a multitone test signal that varies (approaching a music-like signal even more) will show fluctuating noise floor & if this might be of audible significance?
I went through the trouble of checking the source of some of the misconceptions and simply suggested very easy to make measurements many times. I won't bother anymore.
Dual tone or single tone or anything else - it is always the same non-linearity you are exploring. You just need to understand and interpret what you see and measure. In case of single sine tones you use more frequencies. 30kHz FS HD is a tough test.
It does seem very well behaved so it makes me wonder what sort of fluctuation might be seen in that noise floor with a changing multitone test signal?
Yeah, I hear you but are you sure that the DUT behaves the same with a sine wave test signal as it does with a music signal? I go back to Mallinson's presentation of settling time between states as being an issue that standard testing did not reveal but some listeners picked it up & ESS subsequently found a test which revealed it (& it wasn't a test using a sine wave).
BTW, wouldn't 30KHz be considered an invalid test signal?
As Mallinson stated
I understand making the frequencies such that no IMD tones are in the bins with the test signal, but I don't see the point. In any case you can rotate the phase of these tones to vary the crest factor, with 1V tones the peak is 12V at 0 phase and with some fiddling you should be able to get the peak below 2V. That's a nice 6 to 1 range in crest factor.
Superposition does not apply to a non-linear system, the crest factor matters to the distortion result.
Scott, There are two definitions here. One is what M Mallinson was referring to WRT modulator state variable settling The second is what Rob Watts was referring to WRT the difference in noise floor of a DAC comparing a steady state 0dBFS signal to -60 dBFS (or lower) signal. The noise floor is modulating with signal amplitude. The latter is is easily seen in data sheets and what RW claims to be audible.
PS sorry if this is confusing the discussion, I know you guys are on a different track, just wanted to clarify.
T
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Isn't the point exactly that "no IMD tones are in the bins with the test signal" so no confusion between test signal & IMD? I know you know this but can't understand what your point is?
Right
Why is there a difference in noise floor when a different amplitude signal is being processed - is it just some accepted factor or is there a good technical reason behind it?
It would seem that Rob Watts has chased down & substantially reduced NFM so it seems that it isn't a result of the laws of nature at play but some technical practise that maybe is accepted simply because NFM isn't considered worthwhile addressing? (& doesn't show in the standard measurements
)yeah, yeah, yea - let's dismiss it until your nose can be rubbed in it & then make some spurious claim that you knew about it all along.
That is NOT the way the advances in any field are made - if people never considered what might be then we would never move forward
Just saying that any multi-tone test has empty bins that fill up with "grass" which I assume is what we are looking for. Assuming the test tones are much larger than the IMD there should be no confusion.
I think I can only spot 5 errors in what Joe said. Anyone else?vacuphile said:
You seemed to talk of noise modulated before the signal came along, which can only happen in digital systems.mmerrill99 said:
You may find it helpful to distinguish between 'showing up' and 'being present'. The nonlinearity which causes IMD is the same nonlinearity which causes harmonic distortion. The only difference is the frequency, which may in turn change how the distortion 'shows up'. If you put two sine waves A and B into a system with second-order distortion then you get A-B and A+B in the output. We call this IMD. If A and B are the same frequency then you still get A-B and A+B in the output, except now we call A-B a bias shift (which some people seem unaware of) and A+B we call the second harmonic. We call this harmonic distortion. Fundamentally nothing has changed.
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