How did you generate these? (Not that I doubt - just interested).
Certainly stacking them up in fb2k and playing through them, the click seems most click-like with least ringing around file 030. What do the numbers correspond to?
Still, in either case, I can't believe anyone can plausibly claim the ringing from a brick wall filter is not audible when the transition band is within the audible range, and there's content within the original signal to exercise the ringing. I hope Arny will be gracious enough to retract his former claim and accept that this is the case.
Now let's go for (2), is it audible? Well, the question for me is if there is something that prevents it from being audible. The answer is that there are two things that can prevent it:The first one is the frequency of the ringing. If it is outside of the audible range, then it is inaudible. So brickwall filters over 20 KHz will not be audible, which is the case of cd-audio antialiasing and reconstruction filters.
In terms of temporal dispersal, the linear phase filter seems to have reduced temporal dispersal, even as compared to the original wave.Since the 50% is well-qualified as a brick wall filter, there is no obvious proof that brick wall filters are necessarily evil.
The numbers are percentage phase response; so 000 is minimum phase and 100 is maximun phase. You'll need to use a dB amplitude scale with the impulse to see what's going on---linear amplitude scale won't cut it.
You'll need to use a dB amplitude scale with the impulse to see what's going on---linear amplitude scale won't cut it.
Quote from: Arnold B. Krueger on 15 December, 2008, 08:59:31 AMIn terms of temporal dispersal, the linear phase filter seems to have reduced temporal dispersal, even as compared to the original wave.Since the 50% is well-qualified as a brick wall filter, there is no obvious proof that brick wall filters are necessarily evil.So you don't hear any chirping with the linear phase filter?
And you think the 4kHz brick wall linear phase filtered click has "reduced temporal dispersal, even as compared to the original wave"?
Quote from: 2Bdecided on 15 December, 2008, 12:36:37 PMSo you don't hear any chirping with the linear phase filter?Vastly less, as compared to the 5% and 100% samples.
So you don't hear any chirping with the linear phase filter?
I think we may need to review the purpose of the exercise. We are trying to filter out HF noise as effectively as possible with minimal effect on SQ.
My hypothesis is that a brick wall filter rings, and that this ringing can be audible and objectionable.
A more gentle filter will ring substantially less, to the point where the ringing is substantially inaudible.
The spectral and temporal responses of the gentle filter are different from those of the brick wall filter,
but whereas the change in spectral response is small and rarely of any practical importance (I don't say whether it's audible or not),
the change in temporal response is dramatic, clearly audible, and solves an objectionable problem with brick wall filtering.
How would you prove / disprove this in a way that you would find convincing?
Suitable samples are at the end of KikeG's post:http://www.hydrogenaudio.org/forums/index....st&p=604669
BTW this post is a mess of quotes, but I've stopped trying to please this conference software. I can balance quotes on other HTML forums, no sweat. There seem to be some hidden agendas.
I suspect that if we can appropriately control the duration, amplitude and shape of the envelope of the ringing, we might mask it all.
You do understand that the filter need not be brick wall in order to ring.
QuoteA more gentle filter will ring substantially less, to the point where the ringing is substantially inaudible.But, more noise gets through.
Quote from: Arnold B. Krueger on 16 December, 2008, 09:03:59 AMBTW this post is a mess of quotes, but I've stopped trying to please this conference software. I can balance quotes on other HTML forums, no sweat. There seem to be some hidden agendas.At the top of your post, you opened three quotes, then closed five. At least that is what is shown.Cheers,David.
Here's a graph (time x-axis, amplitude dB y-axis) of the phases 0-50% (minimum to linear phase). Phases 55-100% are not shown but look like phases 45-0% mirrored about the y-axis.
IIRC there's a comment by Brian Moore that temporal pre-masking decreases greatly with training, making the pre/post difference even more stark. Something like 3ms vs 20ms for a masker/maskee combination, but that's from memory - I've lost the paper.
The iZotope RX application can display time and spectrum at the same time. Perhaps it helps to see the differences even better.I've picked the phases from 0-100% from left to right in 10% increments.
only the centre one is linear phase - not all of them, as first words of the text imply.
Ah, so we come to the question of what the filter is supposed to be doing, and whether a sharp cut off is more important than the avoidance of ringing.That depends on the application. The point is whether the brick wall filter introduces audible ringing. You stated that it did not. So while you suggest I'm assigning a "zero cost" to the gentle cut off, you are assigning a "zero cost" to the ringing.
In truth, both have a cost - judging which is preferable is a matter for the designer, and application specific.
However, that's was not your original point at all: you implied that ringing is a "zero cost" problem because you believe there is no ringing, and if there is, it isn't audible.
Apparently you haven't kept up with my recent recantation of that position.
In terms of temporal dispersal, the linear phase filter seems to have reduced temporal dispersal, even as compared to the original wave.
Comparison with the original wave is invalid because it has a vastly different frequency response.
We were, but we've moved on a long way from the original question. We're in the audible range now, for one thing.
We always were in the audible range, when we're talking effective filters in the middle of the frequency range of most sensitive human hearing.
Check the title of the thread - the application is "Mastering Captured Vinyl For CD".
What I've learned so far...
...is that it would probably be a good thing if we had filtering tools for vinyl mastering to CD that were based on linear phase filters, or better yet filters that were tipped a bit from linear phase towards minimum phase so that the ringing receives maximum temporal masking.It further appears that said tools might benefit from variable slope features so that a subjective trade-off could be made to balance noise and ringing.I know of no such tools on the market today, but it appears that they would be feasible to develop.Voila: a product opportunity.
The difference "should" be inaudible, yet in A/B (not ABX) tests, the preference for these inaudible filters matches the preference for audible filters demonstrated in this thread - closer to minimum than linear phase; more gentle than brick wall.