Is that a reason for the users or the perps?
Interesting reading JA’s comment to the effect that the Quads measured so idiosyncratically and yet sounded amazing.
Ps.. And no, scottjoplin, it wasn't about ITD...
Yes - and as far as I know, no cabinet resonances or sharp corners with degradation problems.
Well, you make my point further. This is bad loudspeaker data from Stereophile. ONLY near field measurements (or anechoic) are supposed to be used to measure the speaker itself. No one is interested in someone else's room's affect on any loudspeaker being tested. And rooms are not all the same. It is useless info about the ESL its self, otherwise.
The ESL is quite flat as I also measured.
Yes of course, you can't take off part of the frequency content without changing the time domain content.The initial discussion was if cd rate was sufficient. Cymbals were introduced as an offending signal.
My statement is in essence...
3. If the primary signal is high enough in frequency, a modulating envelope may produce sidebands where the upper sideband will exceed the filter cutoff. If that occurs, the consequence will be that the envelope of the filter output will be changed from that of the original.
4. A high bandwidth signal such as a cymbal will have envelope modulated components we can hear, producing sidebands above and below primary, as well as ultrasonic components with both upper and lower content. Filtering the upper part out above Fs will still alter the final reproduced envelope.
What exactly is a Gibbs envelope, and where and how can you see that the decision to stop at 44k was not perfect ?My example of the sine modulated by a sine, or by an exponential, are the easy types. Unfortunately, an exponential does not have one frequency, nor is it time invariant. FFT analysis does not easily provide an instant by instant spectra, so cannot tell us what part of the waveform will be filtered, just what frequencies.
The Gibbs envelope does. It can show us when the product goes above Fs.
That is why I earlier stated that using the Gibbs envelope is the best way to spot when content is pulled.
And, looking at the Gibbs envelope with cymbals, it is clear the decision to stop at 44k was not perfect
Well, the crafty users may indeed develop an open-source system for consumer AES67...but you know the answer for the perps Scott...he same breed of, um human who brought you MQA...if it don't come with a license it's crap!
But AFAIR JA shows frequency response curve is the averaged result of a family of curves taken on different angles. Loudspeakers with higher directivity above 10 kHz will therefore always show less level in that region.
Isn't that exactly what was envisaged in the first place ?Han's,
So, the envelope modulation of a below Fs signal has two sidebands. If one sideband goes above Fs, the filter will remove that, and as you are demonstrating, the resultant output will have a different frequency content as well as a different envelope.
No It doesn't.If you were to run with continuous modulation, you will see that subsequent lobes will flip phase, and that an FFT will not show the within lobe frequency, but only the two sidebands.
Isn't that exactly what was envisaged in the first place ?
I still don't get where you are heading to.
There are technical things one can describe and measure, but in this very case we are looking at Audio signals that may or may not be crippled by filtering the signal above our hearing limit.
That a seemingly frequency shift takes place has everything to do with the subtraction of the "above Brick Wall" and the addition of the Gibbs frequency, both being above our hearing limit, that's it, I see no further magic.
No It doesn't.
See both spectra below, in this case a continuous signal composed of a 20Khz sine modulated by a 4K raised cosine, before and after 20Khz brick wall filtered.
View attachment 818521
There is the benefit of the figure of 8 polar pattern.... lower level of early side wall reflections. The JBL M2 also has lower side wall/early reflection but it is done via sound wave-guide to shape dispersion pattern.