OK, I suppose an excerpt would suffice (in view of copyright) rather than the entire track?
For DeltaWave, a 1.5 - 2 minutes clip is sufficient for analysis
OK, I suppose an excerpt would suffice (in view of copyright) rather than the entire track?
OK--didn't want to use the same track that I used earlier, was thinking about what to use and... the answer became obvious.
For the avoidance of any doubt over musical taste, anyone downloading and listening to these files will be "Rickroll'd"--LOL. First 90 seconds of the 7" Instrumental.
Files (7zip format containing FLACs.)
Link expires in 7 days, so get your skates on...
As lossless was requested and export to floating-point FLAC is not available, to prevent digital overs, above all with the all-pass filter, all files are reduced in level by -6dB and dithered to 24-bit. (Source is 16-bit/44.1kHz.)
Got it. So, let's do these one at a time.
DeltaWave settings used for all of the above are shown here:
Another couple of tests using the same reference file.
TPDF Dither to 8-bits -- "DF Metric" = -31.6dB
Truncate to 8-bits -- "DF Metric" = -35.4dB
Hmm...
And, just in case I have my wires crossed in relation to what is a "better" "DR Metric" value... comparing the reference file to itself -- "DR Metric" = -300dB.
-300dB is the lower cutoff point in DeltaWave to eliminate negative infinity, just in case someone claims that they can hear the difference of -300dB
How about -299dB? ;-)
My own tentative conclusions (or rule of thumb) are that one can hear levels of noise floor modulation down to -200dB - currently we can measure noise floor modulation at -180 dB
Another couple of tests using the same reference file.
TPDF Dither (dither ONLY--no noise shaping loop) to 8-bits -- "DF Metric" = -31.6dB
Truncate to 8-bits -- "DF Metric" = -35.4dB
Hmm... well, we don't know the noise floor of the reference, so how about 4-bits?
TPDF Dither to 4-bits -- "DF Metric" = -12.8dB
Truncate to 4-bits -- "DF Metric" = -15dB
Listening to the "difference" between the source and comparison files, the dithered 4-bit sounds mostly like white noise with, say, some HF percussion breaking through; the truncated 4-bit sounds like a mess of crackly quantization noise.
And, just in case I have my wires crossed in relation to what is a "better" "DF Metric" value... comparing the reference file to itself -- "DF Metric" = -300dB.
That might matter, but only if your name is Rob Watts of Chord Electronics who says this:
So TPDF dither actually makes the DF metric worse by a few dB? How about trying a shaped dither?
For distortion, (2).
To quote from Douglas Self's "Audio Power Amplifier Design Handbook":
"Phase and group delay have been an area of dispute for a long time. As Stanley Lipshitz et al. have pointed out, these effects are obviously perceptible if they are gross enough; if an amplifier was so heroically misconceived as to produce the top half of the audio spectrum 3 hours after the bottom, there would be no room for argument. In more practical terms, concern about phase problems has centered on loudspeakers and their crossovers, as this would seem to be the only place where a phase shift might exist without an accompanying frequency-response change to make it obvious. […] This controversy is of limited importance to amplifier designers, as it would take spectacular incompetence to produce a circuit that included an accidental all-pass filter. Without such, the phase response of an amplifier is completely defined by its frequency response, and vice versa; in Control Theory this is Bode’s Second Law, and it should be much more widely known in the hi-fi world than it is. A properly designed amplifier has its response roll-off points not too far outside the audio band, and these will have accompanying phase shifts; there is no evidence that these are perceptible."
(Slight caveat--Self's book is not a definitive treatise on questions of audibility.)
Sound is a waveform (in time domain).
Does it mean DeltaWave users should always use settings that yield the best possible nulls? Even when different file pairs require different settings?Got it. So, let's do these one at a time.
First, the soft-clip file. Correcting for nonlinear phase differences, I get this (turning on non-linear EQ settings in DeltaWave). Check the results on the bottom status bar, too, as these are additional metrics computed by DW:
View attachment 46671
Now, the Soft-Tube Trident A result:
View attachment 46672
And the 8th-order all-pass filter (also using alternate clock drift computation):
View attachment 46673
DeltaWave settings used for all of the above are shown here:
View attachment 46674
Phase shift of more than 15 degrees or so across an ERB (or critican band) will provoke sensation differences when the right signal comes along. That's a reasonably decent estimate.
Does it mean DeltaWave users should always use settings that yield the best possible nulls? Even when different file pairs require different settings?
This point is important if you want to do something similar to Gearslutz's tests, and especially important for people who only look at numbers without downloading and examining the recorded audio files.
Interesting. Has that been demonstrated?
Conclusions:
(1) Soft Clip and Softube samples have very similar artifact signatures (0.18dB, while 1.5-2.0dB is a critical distance for a good relation of df levels to subjective scores), so Softube sample will sound more close to the original than Soft Clip but the difference is really subtle (needs very careful listening).
[snip]
In other words 8allpass sample will sound less close to the original than two others; the SoftClip and Softube samples will be hard to discern from each other by listening.