Quote from: amirm on 2014-12-02 16:57:58

As to his theory of IM distortion, it is just that: some theory.

That's a surprising statement in this context!
IM distortion from ultrasonic signals, measurable in most hi-fi speakers on the planet, and laughably easy to hear with various signals, is just some theory? Yet the audibility of ultrasonic ringing, suggested but not proven as the reason a filtered signal could be picked out 10% better than random choice in one study, is the important thing?
I would suggest that you can either pick evidence to suit your claims while ignoring evidence that does not, or complain that people aren't being objective. But you can't get away with doing both. In the same thread.
It's really disappointing, because it looked like you wanted to explore all avenues and possibilities when you started posting, but it seems that you weigh evidence by how much it supports your pre-decided conclusions, rather than by any objective criteria.

Cheers,
David.

Does anyone know the crossover frequency for the tweeter in the speaker that was used in this paper?

It really can't be said often enough to ask about more data especialy about the metal tweeter.
I am not part of amirs professionel parallel universe but i often had surprises with building speakers with metal domes.
There was some self-sound mostly unpleasant that was not to measure with simple frequency responses.
It wouldn't come as a surprise to me if the tested filters only triggered a material resonance differently.

https://www.madisoundspeakerstore.com/ring-...diator-tweeter/

Quote from: amirm on 2014-12-02 16:57:58

As to his theory of IM distortion, it is just that: some theory.

That's a surprising statement in this context!

IM distortion from ultrasonic signals, measurable in most hi-fi speakers on the planet, and laughably easy to hear with various signals, is just some theory?

Quote from: Arnold B. Krueger on 2014-12-03 14:40:16

https://www.madisoundspeakerstore.com/ring-...diator-tweeter/

One of the best tweeters ever build imho.

Yes because if you read Monty's blog, it has no measurements or test cases whatsoever.  If this is a real problem, real examples need to be given.

Quote

CONCLUSIONS

3. Our findings are consistent with the idea that
filters with long impulse responses blur fine tem-
poral details of signals. [The idea is diminished in persuasiveness given that the filtering was of ultrasonic frequencies using linear phase.]

the fact that the test involved filters with unrealistically narrow transition bands that lead to unrealistically large  amounts of ringing,

Quote from: Arnold B. Krueger on 2014-12-03 15:14:05

the fact that the test involved filters with unrealistically narrow transition bands that lead to unrealistically large  amounts of ringing,

A fact that you doubtless verified, e.g. by visiting src.infinitewave.ca, assessing the transition band width of those SRCs that are 1) commonly used in music production and 2) not obviously broken by ^*%&$^ design.

A fact that you doubtless verified, e.g. by visiting src.infinitewave.ca, assessing the transition band width of those SRCs that are 1) commonly used in music production and 2) not obviously broken by ^*%&$^ design.

Quote from: amirm on 2014-12-03 14:50:19

Yes because if you read Monty's blog, it has no measurements or test cases whatsoever.  If this is a real problem, real examples need to be given.

Some recent tests using Monty's IM files: https://www.gearslutz.com/board/10576574-post9.html

The point is that a great many mastering tools have a transition band narrower than the paper's 500Hz. Often much narrower.

The point is that a great many mastering tools have a transition band narrower than the paper's 500Hz. Often much narrower.

Quote from: 2Bdecided on 2014-12-03 10:30:05

Quote from: amirm on 2014-12-02 16:57:58

As to his theory of IM distortion, it is just that: some theory.

That's a surprising statement in this context!

IM distortion from ultrasonic signals, measurable in most hi-fi speakers on the planet, and laughably easy to hear with various signals, is just some theory?

Yes because if you read Monty's blog, it has no measurements or test cases whatsoever.  If this is a real problem, real examples need to be given.

The theory also ignores the amplitude of ultrasonics in music.  We can see that in the sample music in Stuart's paper:



The spectrum above 22/24 Khz is what, 90 db lower than peak in the in-band?  IM distortion would be a percentage of this so it will be at even lower levels.

Here is the IM distortion test tracks Arny had us run which we passed with no audible IM detected:



His ultrasonic test tone pairs on the right are nearly clipping level.  Yet they still did not garner detection in the sampling of people who ran it.

The bad news for the Meridian boys is if the mastering people put ringing into the masters, what takes it out?  As I read their materials, their Apodizing filters span of correction is the ringing in the filters in their own equipment.

If we are objectivists, we better be objectivists all the time.

Quote from: amirm on 2014-12-03 14:50:19

If we are objectivists, we better be objectivists all the time.

Good. Then can we agree on these things? Or not?

1. The BS paper reports a listening test where the filtering was detected 10% better than chance (which, in the number of trials performed, is statistically significant)
2. The different scenarios tested all gave broadly similar results overall.

3. Some differences between scenarios became larger when the data was post-sorted and re-analysed, but the rigorous way of investigating this is to re-test these apparently better conditions, not post-process the data looking for the better conditions after the fact.

4. There was no re-test, so at this stage we shouldn't claim differences between filter types, dither, etc.

5. The theories as to why/how the filtered samples were differentiated from the original samples are just that: theories. It would be possible to design listening tests to probe these theories, but this has not been done. At this stage, we shouldn't claim the filtering was audible because of X, Y or Z.

6. No one has done a listening test to probe the audibility of ultrasonic ringing itself. (AFAIK - do you know different?)

7. Audible IMD from ultrasonic signals is readily demonstrable under certain circumstances.

8. The worst audible IMD from ultrasonic signals is far more easily audible than the worst effects of ultrasonic ringing from the "worst" "CD" sinc filter.

9. Measurable IMD from ultrasonic signals reduces with ultrasonic signal level, often almost proportional to some positive integer power of the signal level, rather than linearly. (i.e. it falls away surprisingly quickly).

My objective conclusion from all the evidence is that neither mechanism should be readily audible, but in a test where people were just about able to hear some kind of difference, that difference could be down to one, the other, both, or neither - pending further investigation.

As someone else has already mentioned, Sony put (switchable!) filters on the output of their SACD players. This is an admission that it will sometimes be better to remove ultrasonic signal components, long before Monty mentioned it.

What you are advocating is being unable to sell better masters to an audiophile without the added expense of senseless recording overkill, because said audiophiles have been 'educated' that they need a gold plated Hummer with artillery mount to drive to the corner store.

Is this a benefit to the industry? to anybody?