Sunday, June 21, 2020

Archimago on Ultrasonics

I think this is excellent reporting, as always from Archimago (even when I don't agree).

I do ultrasonics because I can.  As Boyk showed, it's there.  What does it do?  Nobody knows.  But I want my system to "do it all," not just to what has been proven necessary.  The ideal bandwidth would be DC to Light, but I'm willing to compromise on that.  I would agree that 40kHz is all one ever needs (along with 96kHz sampling rate).  That's not so unreasonable, I think.  There have been many many legendary systems with ultransonic response as good as that or better (including "massless speakers" like Iverson's Corona, and Diamond Tweeters).  Are they really better because of that?  Who knows, but I want to be in that league.

 (Meanwhile, I think it is unreasonable to badger people into using planned obsolescent Personal Computer based delivery systems like USB in order to escape the potential -145dB sidebands caused by the SPDIF, as Archimago does.  I think it's fine if he personally chooses to do things that way, but not so fine to stir up audiophilia nervosa regarding jitter to justify it, all while claiming that jitter doesn't matter at the same time--thereby having it both ways.)

In my fully sighted testing, I always prefer having the super tweeters on.  I know this does not prove anything.

One whole avenue unexplored by Archimago is this:  What if the ultrasonics influence the non-ultrasonics?

I tend to find that enabling the super tweeters removes hardness and glare.  I think what may be involved is that the ultrasonics have a beneficial masking effect, which is of course there in the live performance as well.  What's masked is the painful frequencies like 6kHz and 12kHz that sound unpleasantly "metallic."

In live performances, brass instruments never sound overly metallic, just nicely metallic.  In recordings lacking extended highs, brass instruments can sound positively harsh.*

In this process of so masking, somehow ultrasonics help also help delineate the bass..

So it's not so much about what you hear, and no I don't hear even loud tones much above 16kHz, but how ultrasonics affect what you do hear.

And this isn't so much dependent on preserving linear phase and all that.  Though I'd like to agree with my friends that "it's not the frequencies, it's the high slewing," actually I know I haven't come close to anything like phase linearity with my super tweeter deployment, and it still works, I think, whatever it's doing.

Just like in other frequency ranges, preserving the actual signal envelope is key, the phase relationships normally hardly matter, if at all.

I don't care to prove I need high frequencies.  Failure to prove I can hear it wouldn't mean I don't.  I'd prefer to keep it, so long as it's not too hard, and keep making it better.  Maybe eventually I'll be able to prove I need it.  I think 2x clearly audible bandwidth is reasonable (for me, that's actually 32 kHz).

Regarding the 28kHz spurious tone in one recording.  I don't think that's necessarily a good thing.  But if that was the mix the artist and producer signed off on, and if what you want to hear is the mix the artist and producer signed off on, then that is it, defects and all.  Without the "defects" it's not the same thing, and potentially could be less satisfactory due to the masking I have described.

(*It could be this is entirely caused by more mundane effects, including the need for a Linkwitz Dip.)

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