Audibility of digital reconstruction filters

[Superdad]

?? I think the response was simply concentrating on ringing behavior, not saying that was the only difference among filters.

 

Okay, but as all of us Audirvana+/iZotope SRC users can attest, adjustment of the "ringing" slider (as well as all the other filter parameters) is VERY audible--right down to the limit of the granularity of available adjustment (0 to 1.0 in 0.01 steps; 0 being minimum-phase all post-ring, 1.0 being linear phase equal balance between pre and post).

 

My hearing barely goes out to 14kHz, and the effects I hear are all about the micro-second attack of the notes and how they propagate into the room. For me it rather audibly obvious.

 

It is also quite easy to radically better in s/w the performance of the average DAC with SRC to 176.4 or 352.8 to virtually bypass the chip's internal filter. I am not sure at all why the audibility of filter parameters is still controversial for some.

[Superdad]

Science would say first, "Is there a difference?" To answer that, sadly, the experiment must eliminate biases of all kinds. Once established that there is a real and repeatably detectable difference, a hypothesis or three might be formed, then a proof sought.

 

"Good Science" must by definition take into account the errors in the entire experimental system. Unfortunately, some of those errors include bias in observation, but there are many others as well. If as many errors as possible in the system are to be accounted for, then influence of biases must be included.

 

Oh boy, here we go again. And on the first page. zzzzzzzzz…..

[Superdad]

Yup, a snooze fest... Gotta wonder why you post this stuff Dennis.

 

Hang on here. I was snoozing in response to dc2blurlight's attempt to turn the discussion down the rabbit hole of proof and bias and all that usual nonsense argument we have been over and over, round and round.

 

I don't mind at all Dennis starting a technical discussion and asking questions about the measurement and audibility of digital filters. This is a topic of great interest to me and I especially like it when knowledgable people jump in to explain things from both sides. That's how we all learn. I'd love to see Miska, PeterSt., John Swenson, Hansen, Rankin, Siu, Mallison, etc., along with Don Hills, Mayhem, Fokus and the like all jump in and argue/post/graph this out.

 

I just get bored when conclusions and sides are drawn--and the whole measure versus hear BS--before more than a couple of experienced people even have a chance to jump in.

[Superdad]

If someone did an impulse measurement on these things, that would be really interesting.

 

You mean like the sort you can look at at SRC Comparisons ?

 

 

I cited some references that showed a few things that have been proven to not be as audible as we thought.

 

What did you cite? The boogyman of "bias?"

 

I know from listening to a lot a DACs--and from improving on generic filters with s/w--that filter design can account for considerable difference between DACs. It's by no means the only important thing, as there are a hundred other design and implementation variables that are factors in the final sound.

 

So if folks want to discuss filters, let's do that. If it just turns into an argument about audibility then I'll be happy to tune out. To me, filters are as easy to hear as the difference between MP3 and WAV, but whatever...

[Superdad]

Going instead to the middle step of what is the result of said pre-echo and ringing? What artifacts are produced? Do they really align with causing the differences claimed audible by some. Thus far it appears the artifacts of digital filters mostly are above any frequency we can hear. Some other artifacts are possible, most highly improbable to actually occur, and if they did are so low in level they could not matter.

 

Hi Dennis: You (and others) might find some of PeterSt's dirac impulse captures quite interesting: Phasure NOS1 USB Special Measurements

It is a long post, but scroll way down to about the bottom 15 graphs. It is not all about just his "arc prediction" filter. I found it kind of eye opening to see some of these differences resolved.

 

I can't tell you why I can hear the changes made by small changes in filter settings, but having tuned a few both alone and with others, I can assure you these things are important. Also, given the nature of what I hear (related to transient attack and also bass propagation) I am not sure if headphone listening is a good way to hear these changes. I admit to not being a big headphone listener, so maybe that is why I have a hard time judging the presentation full-sized instruments on them.

[Superdad]

If the bone conduction material has any relevance, it is that ultrasonic resonance of the brain can cause masking around 12-16 khz. Would seem the reverse of accurate reproduction to purposely mask what is heard. And no ultrasonics don't mask sound in that range in normal live listening because bone conduction in such conditions is -60 db below air conduction. If one wanted to mimic this masking you don't need resonance of the brain at 29 khz. You could insert your own low level noise into the 12-16 khz band to achieve the same result. You don't have to resonate the brain at ultrasonics to cause vascular excitation of the hearing mechanism.

 

Hi Dennis:

I'm not feeling well tonight so I am having a hard time following this conversation properly. Can either of you comment on how tinnitus figures into this? From what I have read and heard (I have mild tinnitus myself), tinnitus is actually the ear/brain self-generating at the very frequencies where hearing loss has occurred--and for many, myself included, that is right in the 12-16kHz range.

 

I have tested myself and can still hear (up to maybe 15kHz), but it is interesting to start to think about the ringing in my head (some times worse than others) as bone conduction. I always thought of bone conduction just at very low frequencies. BTW, I bet a lot of people have some tinnitus and don't even realize it because they live in a city. Out here in the country it is eerily (no pun intended) quiet. My studio/office has a noise floor of about 36dB. At times I have wanted to stick my measurement mic in my ear to measure the frequency/amplitude of the ringing! (Just kidding; of course that would not work, though the small diameter capsule would fit snugly . )

 

Goodnight,

AJC

[Superdad]

The eardrum would be an unusual transducer to have a limited waveform steepness at continuous signal input, but respond to steeper waveform rising transient. Most transducers work somewhat the opposite way.

 

But our ear drums have an awesomely powerful computer--evolved specifically for transient analysis--attached to them.