Stuff in progress

I have some suspicious evidence that HDCD software conversion isn't doing quite as well as my Denon DVD-9000.  The software converted version is indistinguishable visually from DVD-9000 output using Audacity at high signal levels, where you can clearly see the HDCD system working (and I now think it is in fact essential for high dynamic range recording and 16 bits...because real high dynamic range recordings can have 17dB above average peaks).  But at medium levels where the HDCD is barely working, what seems to be happening is there are tiny super-peaks in the 24/96 data from the Denon, so the Denon output looks ever so slightly peakier.

What I think this means is that HDCD is being applied at the 2x oversampling level (or higher), not to the original data stream, and in fact I've always believed that was how it was done (and why no simple software conversion tool would suffice...unless it was doing a compatible form of oversampling as well...and the digital filter changes I always believed were being done).

It's not at present evidence of variable filtering because the recording in question, Poems of Thunder, does not use the variable filter feature!  At least in the output, perhaps variable filter was used in recording (or perhaps not).

Notably Reference Recordings don't show the Transient Filter flag in their HDCD's either.

I was meaning to investigate that, then I noticed my recording had clipped, so I tried lowering the preamp level to -5dB (-4.5dB has been my standard for HDCD for years, to account for the fact the Denon actually puts up to 4.5dB more output with HDCD's than anything else...which it appears nobody else does, or perhaps other like California Audio Labs did too back in the early days of HDCD, I don't know.

So I re-recorded, and then I noticed something I should have been thinking about from the moment I noticed -93dB hum (60Hz) in recordings from the Denon: I'm using a standard grade Radio Shack 3 foot interconnect for the Denon and my Emotiva Preamp.  I've ordered a cable of my new standard (especially where shielding is important): Blue Jeans Cable LC-1.  It's thick and has the best shielding system and low capacitance too.

So I'm holding off on more tests until I get that cable upgraded, and I might even be able to demonstrate a measurable cable difference here, if the LC-1 lowers the hum a few dB.  And what will it do elsewhere?  It might even raise the apparent noise level because low capacitance.  We'll see.

It can't affect the Oppo which is connected with teflon balanced cables.  Recordings from the Oppo show no visual evidence of 60 Hz in their output.  But they show about the same level of high frequency noise, which is apparently therefore the fault of the sampler I'm using now, the DA-3000.

I think the Lavry AD10 is a tad better, the specs suggest 4dB better.   I need to get that fixed too.

Even then, the AD10 will still have quite a bit more noise than the Oppo....even a bit more than the Denon!

It hardly makes sense to concentrate on making reference transcriptions of anything, including vinyl, until I get the Lavry fixed.