Haha...

I can play tracks #1 and #2 at any XX volume settings (track #1 played back 1.5dB lower than track #2) and the difference in sound is obvious. BUT... when I play back at -1.5dB and 0dB respectively, they sound identical!

Mani.

Here they are...

The recording chain is:

Mach II -> NOS1a -> Prism ADC -> Tascam spdif input

1. Drum kit (XX at 0dB):

https://drive.google.com/open?id=0B0PU5LO5jVjfMVQyYjg2Tkp2NEE

2. Drum kit (XX at -1.5dB):

https://drive.google.com/open?id=0B0PU5LO5jVjfajJkN2N0SWl6Uk0

3. -14dB 1kHz sine wave (XX at 0dB):

https://drive.google.com/open?id=0B0PU5LO5jVjfREwwS0pwMkd2Ujg

4. -14kHz sine wave (XX at -1.5dB)

https://drive.google.com/open?id=0B0PU5LO5jVjfWURHS0N4RHg1N2c

I used 'my own' sine wave for the last two (ripped from a test CD) because it was already at -14dB and meant I didn't need to go through the preamp to attenuate further. But if these 2 files are not good enough for you, then I will redo them with the 1kHz file you linked to, but won't be able to sort the ICs from the preamp to the ADC until this evening.

Listening to files #1 and #2 here, the effect I described at the beginning of this thread is very clear to hear.

Mani.

Will do later today...

But I was also thinking of simply making two 10 second recordings of a track where the effect is pronounced, one at 0dB the other at -1.5dB. You could match volumes at your end and take a listen - as long as you're not at 0dB, you should hear what I'm hearing, no?

But I'll start with your test.

Mani.

Yep, the change in SQ is still easily audible:

-1.5dB/12 sounds like -1.5dB/11, just a little louder.

0dB/12 sounds like 0dB/11, just a little louder.

Do you want me to get my ADC out again???

Mani.

BTW, I've just compared a few tracks with quiet beginnings in 3 ways:

1. XX set to 0dB, preamp set to 11
2. XX set to -1.5dB, preamp set to 12
3. XX set to -21dB, preamp set to 23

There is a slight difference between 2 and 3. There is a massive difference between 1 and 2/3. Something is going on...

Mani.

You can judge from the first few seconds of various tracks, some of which never go about -20dBFS.

I know what I'm hearing... 0dB sounds totally different to any other attenuation level.

Mani.

But music is dynamic, so you're never going to be in the sweet spot for very much of the time, irrespective of where you set the attenuation, right?

All I can say is that I have now tried a whole bunch of tracks with RMS levels ranging from -30dBFS to -8dBFS (according to TT-DR meter) and changing the XX attenuation from 0dB to -1.5dB has exactly the same effect on SQ on all of them.

Coincidence, or what?

Mani.

On further listening...

On many tracks, I actually prefer the 0dB setting - there's way more energy in the upper-bass/lower-mid area, which gives a fuller, fatter sound. With 'thin' recordings, this is very welcome. But if the recording is already very 'thick' sounding, 0dB just makes it sound too boring.

But the point remains that there is a very big difference in sound between 0dB and any other attenuation setting, and I don't think there should be.

Mani.

Yes, I was using the Custom Filter (705600 Low). But I can hear the same effect with AP too - maybe slightly more difficult to hear because there is more 'sparkle' with AP anyway, so the 'dullness' at 0dB is somewhat compensated for.

I've never tried Volume Normalisation.

Mani.

I've just discovered something really weird with the XX volume control...

For the last couple of weeks I've had my old Pass Labs X1 preamp present in my office system because I've been playing around with loads of different components. The messing around with components ended yesterday evening, but I was too lazy to take the preamp out of the chain. So I set XX to 0dB and had music in the background as I worked. I was quite shocked at the audible clipping in so much of the modern pop music I tried (the loudness wars really have gotten totally out of hand). In the past I would have switched PeakExtend on, but last night I just turned the XX volume to -1.5dB. Of course, the audible clipping stopped, but I was shocked in the change in the overall sound.

At 0dB, the sound is thick, full, and pretty boring. At -1.5dB (and any greater attenuation setting thereafter), the sound immediately comes to life. And I'm now talking about well-recorded stuff, well below clipping level.

Peter, there is something really strange going on. There simply shouldn't be such a big difference between 0dB and any other volume setting (assuming no clipping).

Mani.

Hey Peter, I had two objectives for doing these tests:
1) Figure out how good my current ADC is - it's a 20 year old unit (older than my previous PMII), and I needed to know whether it's up to the job of digitizing my vinyl
2) Figure out which digital transport to use in my office

I now have the answers to both of these and I'm happy to put this whole endeavour to bed. But let me know if you'd like me to do anything else with the Tascam.

Thanks again for all your effort.

Mani.

The Tascam is a stand-alone unit with its inbuilt software - no connection to any PC. I record straight to an SD card in the Tascam. I then take the SD card out of the Tascam and transfer the files to my PC.

I have an old CD/DVD player here with an spdif output. Later, I will take a capture and then we can compare to the CD rip.

Mani.

So, any thoughts on why #2 vs. #1 is all downwards and #3 vs. #1 is all upwards? (BTW, the guy over at ASR believes both are downwards.)

Another guy at ASR has taken a listen to the files and agrees with my initial subjective assessment of how #2 or #3 differ in sound. He's also listened to #8 and #9 (through DAC/ADC chain) and can hear differences there too.

Mani.

Haha, of course!

Mani.

Thanks for doing all this Peter - I know it can't be of much interest to anyone else, but it certainly is to me.

Sweet dreams

Mani.