Re: [Qtractor-devel] Loss of sound quality

[Ralf M. <ral...@al...>]

Hi all :)

1. Clicked /usr/src/qtractor/sqrtest1 (to open it with Qtractor) set 
path and changed to 32-bit float.

2. Saved and closed Qtractor.

3. spinymouse-sudo@64studio:~$ jackd -Rdalsa -dhw:0 -r48000 -p512 -n2 -Xseq

4. spinymouse-sudo@64studio:~$ qtractor -v
Qt: 4.4.0
Qtractor: 0.4.3.1409

5. spinymouse-sudo@64studio:~$ jamin -V
jamin 0.95.0
[snip]
spinymouse-sudo@64studio:~$ jamin
[snip]

6. Bypassed JAMin EQ, the 3 compressors and the limiter.

7. Clicked /usr/src/qtractor/sqrtest1 (to open it with Qtractor).

8. After saving, closed Qtractor because of a sample rate warning and 
clicked /usr/src/qtractor/sqrtest1 (to open it with Qtractor) again.

9. Disconnected all audio clients.

10. Connected ...
Qtractor Master/out_1 --> Jamin in_L
Jamin out_L           --> Qtractor Master/in_1
Qtractor Master/out_1 --> system playback_1
Qtractor Master/out_1 --> system playback_2

11. Checked the levels.
All faders set to 0.0 dB, the output signals were at - 6 dBFS, while the 
input levels were a little bit less than -6 dBFS *?*.

12. Punch in/ out recording.

13. Disconnected ...
Qtractor Master/out_1 --> Jamin in_L
Jamin out_L           --> Qtractor Master/in_1

14. Saved and compared by listening and watching the meters.
While the source waves were at -6 dBFS, the level of the recordings 
jumped for each frequency to another level around a little bit less -6 dBFS.

15. Looped to compare the second square waves only, while both faders 
were set to 0.0 dBFS and a second time while the source wave's fader was 
set to -0.5 dBFS (the recorded wave's fader kept at 0.0 dBFS).

I used the near field monitors and the headphones for listening. I 
wasn't able to do this very often because of getting something similar 
as a combination of tinnitus and circulation problems, so I need to make 
short rests between comparison sessions.

It's a fact that there's a difference between the sounds, call it a loss 
or win or whatever ;). I wasn't able to do this test without having 
psychoacoustic effects.

OT: Again I lost the menu bar. The F-keys for the mixer and the 
connections worked, also the shortcut for opening a session, but I 
didn't get the options by shortcut. I was taking care that Qtractor's 
window always was focused. Until now I didn't restore the configuration 
file to get back the menu bar.

16. Watching the waveforms by Audacity.
The screenshot might be the most important issue of this test.

I imported sqrtest-55-48000-3000-1.wav, it's the upper wave and 
sqrtest1-bounced-1.wav, it's the wave below. Okay, the time shift is 
because there seems to be latency even for recordings internal the 
studio in the box *?*.

The 107.8 KB screenshot is attached.

17.

spinymouse-sudo@64studio:/usr/src/qtractor/sqrtest1$ ls -Al
total 5116
-rw-r--r-- 1 spinymouse-sudo src  288044 2009-10-07 19:43 
sqrtest-1000-48000-3000-1.wav
-rw-r--r-- 1 spinymouse-sudo src  288044 2009-10-07 19:43 
sqrtest-110-48000-3000-1.wav
-rw-r--r-- 1 spinymouse-sudo src 3456080 2009-10-22 13:13 
sqrtest1-bounced-1.wav
-rw-r--r-- 1 spinymouse-sudo src    7116 2009-10-22 13:46 sqrtest1.qtr
-rw-r--r-- 1 spinymouse-sudo src  288044 2009-10-07 19:43 
sqrtest-220-48000-3000-1.wav
-rw-r--r-- 1 spinymouse-sudo src  288044 2009-10-07 19:43 
sqrtest-440-48000-3000-1.wav
-rw-r--r-- 1 spinymouse-sudo src  288044 2009-10-07 19:43 
sqrtest-55-48000-3000-1.wav
-rw-r--r-- 1 spinymouse-sudo src  288044 2009-10-07 19:43 
sqrtest-880-48000-3000-1.wav
spinymouse-sudo@64studio:/usr/src/qtractor/sqrtest1$ tar czf 
~/Desktop/sqrtest1_Ralf.tar.gz *


You can download sqrtest1_Ralf.tar.gz from here:

https://disc.alice-dsl.net/

- User name: ral...@al...
- Password: 64studio

Please let me know when you downloaded the test Rui. After you 
downloaded it I'll keep it some days, if other people wish to download 
it too and then I'll delete it.

Cheers,
Ralf