[LAU] Sound quality of the Focusrite Scarlett 18i20 2nd Gen

[Ralf Mardorf]

On Sun, 8 Jan 2017 23:29:31 +0100, Johannes Kroll wrote:
>Would still be interested in the comparison recordings you
>mentioned.

I couldn't use the same cables for the RME and the Focusrite test, the
cables used for the Focusrite were better, newer, shorter. However,
directly connecting the Focusrite by a balanced cable to itself,
there isn't audible anymore, what still is audible, when connecting the
RME and the Focusrite to other equipment by unbalanced cables. I've got
an Ardour5 test as 179M tar.gz and could send it of list to some
people, if you off-list ask me to do so.

I'll sent it to you Johannes, you don't need to ask.

More details, especially important in regards to the level of the
Focusrite:

[rocketmouse at archlinux ~]$ uname -rm
4.8.13-1-ARCH x86_64
[rocketmouse at archlinux ~]$ rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND	
  121 FF      90   - 130  0.0 S    irq/19-ehci_hcd	
  126 FF      90   - 130  0.0 S    irq/16-ohci_hcd	
  146 FF      89   - 129  0.0 S    irq/17-ohci_hcd	
  151 FF      88   - 128  0.0 S    irq/17-ohci_hcd	
  271 FF      85   - 125  0.0 S    irq/18-snd_hdsp	
   32 FF      50   -  90  0.0 S    irq/9-acpi	
   48 FF      50   -  90  0.0 S    irq/8-rtc0	
   74 FF      50   -  90  0.0 S    irq/26-radeon	
  111 FF      50   -  90  0.0 S    irq/1-i8042	
  128 FF      50   -  90  0.0 S    irq/14-pata_ati	
  129 FF      50   -  90  0.0 S    irq/15-pata_ati	
  135 FF      50   -  90  0.0 S    irq/22-ahci[000	
  249 FF      50   -  90  0.0 S    irq/7-parport0	
  970 FF      50   -  90  0.0 S    irq/27-enp3s0	
    3 TS       -   0  19  0.0 S    ksoftirqd/0	
   17 TS       -   0  19  0.0 S    ksoftirqd/1	

[rocketmouse at archlinux ~]$ pacman -Q ardour5 jack2 
ardour5 5.5-1
jack2 1.9.10.r202.gf2ece24-1
[rocketmouse at archlinux ~]$ cat .jackdrc_rme_hdspe_aio 
/usr/bin/jackd -dalsa -dhw:HDSPMx579bcc -r44100 -p256 -n2
[rocketmouse at archlinux ~]$ cat .jackdrc_scarlett18i20 
/usr/bin/jackd -dalsa -dhw:USB -r44100 -p256 -n2

1.

[rocketmouse at archlinux ~]$ $(cat .jackdrc_rme_hdspe_aio) >/dev/null
2>&1 & qjackctl & ardour5 >/dev/null 2>&1

05-weather_with_you/audio_out 1 -------> playback_1
05-weather_with_you/audio_out 2 -------> playback_2
capture_1 -----------------------------> rme unbalanced/audio_in 1
capture_2 -----------------------------> rme unbalanced/audio_in 2

unbalanced outputs were connected with unbalanced inputs

hdspmixer controls were set to 0.0 and -∞

qjackctl did show no xruns

2.

[rocketmouse at archlinux ~]$ $(cat .jackdrc_scarlett18i20) >/dev/null
2>&1 & qjackctl & ardour5 >/dev/null 2>&1

05-weather_with_you/audio_out 1 -------> playback_5
05-weather_with_you/audio_out 2 -------> playback_6
capture_3 -----------------------------> focusrite balanced/audio_in 1
capture_4 -----------------------------> focusrite balanced/audio_in 2

balanced outputs were connected with balanced inputs
btw. the first time I used the Focusrite balanced instead of unbalanced

the input pots of the focusrite were set to 0
this isn't the optimal level, but the only way to visually ensure that
left-right-balance is correct

qjackctl did show 0(2) xruns

Regards,
Ralf