BATC Forum

On a whim I plugged a behringer UMC204HD into the Portsdown 4 and was immediately delighted that the RTL receiver played audio through it with high quality stereo sound. However, as with all things, there are two issues.
1. I can't work out how to get testcard or TV transmit to see it as the audio input.
2. Langstone will not work unless the CM108 cheapo usb audio is plugged in.

How can I have the behringer function as the default USB audio card for both TV and Langstone as well as RTL receiver?
(step by step idiots version would be appreciated)

Short answer - you can't.
I have a similar audio interface for my computer but would not expect it to work with the Portsdown 4/Langstone once I had read the problems people have had with usb audio interfaces. I have two different cheap usb audio cards which both work with my setup ( once I plugged the Pluto directly into the RPi !! ). I get stereo DATV audio. I would say that as it is digital then the quality should be good but having tested a Philips CD player against a Sony CD player in the early days of CD's I know there can be vast diferences.
If you just used the cheap usb audio card and connected it to your HD audio interface with audio leads, that would work for getting your mics in. The audio output may not need to go into it unless you have it wired into an audio setup.
The days of HiFi audio seem to be over now it is all digital. Everybody thinks that digital equals HiFi. I still like class A audio amps, still have a Radford HD250 and LS 3/5 speakers. I also have LS 5/7's but sold my LS 5/8's. My favorite speakers were a pair of Wireless World transmission lines that I made using Kef speakers and a Radford crossover. My Stax electrostatic headphones are going up in secondhand price just like the speakers. But younger people would wonder what all that was and are happy with their earbuds, MP3 and bluetooth!!
Anyway why do you need to listen using HD audio...............

Martin G8LCE

You can change the sound device used by Langstone but it involves editing some files.

Log in using SSH.

Enter aplay -L to display a list of the available audio devices.

Note the hw: entry that corresponds to your device.

You then need to edit the /Langstone/Lang_TX.py and Lang_RX.py files to change
‘hw:CARD=device, DEV=0’ to match your device.

I will have a go at editing the .py files later today, hopefully I can find where to get the Portsdown configured properly too.

I have read a little deeper into this device with Linux this morning and have been pleased to find that the U-Phoria interface operates class-compliant and therefore has native support within Linux, as well as windows and macOS.
The reasons I decided to try this device all that..
1. It has balanced inputs and outputs therefore reducing noise.
2. I can control the levels more easily and accurately on the fly
3. I can control the mix between input and playback coming out through the monitor speakers completely eliminating feedback or echos
4. The design matches the Moncaso case really well I will look really good for rallies and demonstrations

I've been able to pick up quite a few of these over the past few years very cheaply, everything from the UMC202 (two in two out) up to the UMC1820. The two channel versions, At an average $15-20 in a junk store or on FB marketplace, have only cost a little more than the open PCB CM108 cheapo devices which are costing me $10 each from a US supplier.

g4eml wrote: ↑

Thu Oct 01, 2020 10:01 am

You can change the sound device used by Langstone but it involves editing some files.

Log in using SSH.

Enter aplay -L to display a list of the available audio devices.

Note the hw: entry that corresponds to your device.

You then need to edit the /Langstone/Lang_TX.py and Lang_RX.py files to change
‘hw:CARD=device, DEV=0’ to match your device.

I think I have selected the appropriate entry per your advice, hw:CARD=U192k,DEV=0, unfortunately I got the black screen with buttons as with not sound device at all.

The entire list for the device looks like this:
default:CARD=U192k
Default Audio Device
sysdefault:CARD=U192k
UMC204HD 192k, USB Audio
Default Audio Device
front:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
Front speakers
surround21:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
Direct sample mixing device
dsnoop:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
Direct sample snooping device
hw:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
Direct hardware device without any conversions
plughw:CARD=U192k,DEV=0
UMC204HD 192k, USB Audio
Hardware device with all software conversions

If the name 192k refers to the sampling rate and that is the only one that it supports then it won’t work. Langstone needs a device that supports 48K sampling rate.

It could be that I need to switch the sampling rate, it definitely is not 192k only. My logic would say that where I have to change that device name in the .py files I should also change false to true to force the sample rate change. Unfortunately that didn't work, neither did going in to alsamixer and ensuring that the device was there, selected, and gains turned up..
As the .py files has several sink statements maybe I should try pacmd to set as default device?

Looking at a totally unrelated forum I found that someone had an issue playing web audio through the UMC204HD due to a sampling rate issue. The posted solution was to change the identified device to plughw:CARD=U192k,DEV=0 which then opened up all possible sampling rates. I will attempt this next and report back.
(Note: I intend to find a way to make this work so that those who wish to can use better quality audio gear with balanced audio etc.. if ultimately impossible I will then investigate DAC hats)

g4eml wrote: ↑

Thu Oct 01, 2020 10:01 am

You then need to edit the /Langstone/Lang_TX.py and Lang_RX.py files to change
‘hw:CARD=device, DEV=0’ to match your device.

Just double checking.. Is it the .py or .grc files that I should edit?

The .py files are the ones used.