Multiple Loopback soundcards required?

I got wfview up and running with Ubuntu using the -s parameter on command line to adress my IC-7300 and my IC-9700. APRS is running nicely with XASTIR plotting the stations.
I want to run WSJTX on my IC-7300 in parallel. Do I need to define additional loopback devices … and is there anybody who has already done son?

Vy 73 de
Rolf, DL8BAG

Hi Rolf,

Indeed I have done this. You need two loopback devices. One for the transmit audio path, and one for the receive audio path. Each loopback device has two “endpoints”, which correspond to either side of the virtual patch cable between programs. One program sits on one side of the patch cable, and the other sits on the other side of the patch cable.

I think our Audio Setup page in the manual covers this (although it may not explain it completely).

Let me know if you need further info,

de W6EL

Hi Elliot,
I guess that I will need additional information but I will experiment a little beforehand.
Vy73 and thanks a lot for your help.
Rolf, DL8BAG

If you look here, carefully, you’ll see the WSJT-X comments on configuration:

That’s pretty much what I’ve done on mine. The device names may be a little different, but look for the similarities with what you see in the manual.

Receive audio path will be:
radio → wfview → Audio Output Combo Box → Loopback, Dev=0 → Loopback, Dev=1 → WSJT-X

Transmit path:
WSJT-X → Loopback_1 Dev=1 → Loopback_1 Dev=0 → Audio Input Combo Box → wfview → rig

That either made it make sense or made it worse! Sometimes you will see “Loopback 10” and “Loopback 11” instead of “Loopback_” and “Loopback_1”. It really depends on your audio system.

de W6EL

Also it may help to open WSJT-X first, before wfview, so that WSJT-X can have the sound format and sample rate that it desires. wfview can adapt pretty well to any format.

That’s the text I read very carefully and it was very helpful. Today I was looking for some details on virtual-sound.conf. I currently believe that I need to define two more loopback devices in that file but I don’t know how to. Thanks for the hint regarding the name of the sound devices. I was a little confused because my devices have names with the underscore.
Vy73 de
Rolf, DL8BAG

Hi Elliot,
your explanation was really helpful. And of course, thank you very much for your efforts. :wink:. Somewehere in the forum I read about how to identify the different sound cards. I will dig into that. When running APRS on 2m and WSPR in parallel, I need a second set of loopbacks. Although having found and read modinfo snd-aloop I am not sure whether I understood it correctly:

Does it mean that I should have the following content in the file virtual-sound.conf:

alias snd-card-0 snd-aloop

options snd-aloop enable=1,1,1,1 index=10,11,20,21

Vy 73 de Rolf, DL8BAG

Identifying the appropriate sound cards when running IC-7300 and IC-9700 with two instances of wfview cannot be difficult because I have the 7300 connected via usb and the 9700 via Ethernet.

That would give you four loop backs!! You just need two, just exactly like our example in the documentation. Each loopback has two “ends” identified by the DEV parameter visible with some audio systems.

What’s in our documentation is exactly what is on my computer. And it works for me with all the digital mode programs I have tried.

That is my intention,

I would like to run

  1. IC-9700–>wfviev–>direwolf–>Xastir–>direwolf–>wfview–>IC-9700 and a second session in parallel

  2. IC-7300–>wfview–>wsjt-x–>wfview–>IC-7300

at the same time

Currently it is almost working this way but without wfview.

Your answer showed me that I didn’t explain good enough what I want to do :wink:

Nevertheless, your answer was again very helpful.

Vy 73 from Bonn in Germany


Ahh ok, two radios! Well, fancy!!

Keep us posted, that’s a fun one.

I’d really like to be able to label the loopback devices, let me know if you figure out how to assign them better names.

de W6EL