Getting Poor Audio Quality With DSD+

[CanesFan95]

I'm running DSD+ on Windows 7 64-bit, and despite having a strong signal strength, I always get partly garbled audio no matter what I do with the audio settings. Sometimes the audio cuts out alltogether. I'm using SDR# with a RTL-SDR R820T2 RTL2832U 1PPM TCXO dongle. I have the same problem on a tapped scanner. What are some settings I should try? Here's some shots of the wave form and signal strength in SDR#. And, do these CACH ERR messages mean I'm doing something wrong? What's the best sample rate to choose, and should I change the setting under the Recording or Playback tab?

 

[slicerwizard]

I'm running DSD+ on Windows 7 64-bit, and despite having a strong signal strength, I always get partly garbled audio no matter what I do with the audio settings. Sometimes the audio cuts out alltogether. I'm using SDR# with a RTL-SDR R820T2 RTL2832U 1PPM TCXO dongle. I have the same problem on a tapped scanner. What are some settings I should try?

FMP24?

Here's some shots of the wave form and signal strength in SDR#. And, do these CACH ERR messages mean I'm doing something wrong? What's the best sample rate to choose, and should I change the setting under the Recording or Playback tab?

Can't see any of your settings. Bandwidth looks too low though.

 

[CanesFan95]

Sorry, I don't know what "FMP24" means? I increased the band width and here's the SDR# settings.

 

[AM909]

Set bandwidth to 15 kHz.

Check out Advanced Decoder Options in DSDPlus.txt in the DSDPlus install directory. Build a batch file to step through the various values as shown and look at the resulting scores. Add the best params to your normal command line and see if you get good audio. Worked for me. Might be necessary per-site or even per-channel.

If you can find someone that will talk long enough, post a 30-second audio clip.

 

[adcockfred]

In sharp set band width to 5k order 10 uncheck filtered audio. In dsd in fmp cuff spectrum rate to 20 in dsd window toggle a to 100

 

[adcockfred]

Oops sorry f m p c f g. And in sharp don't run vol all the way up. R f gain in 30 's

 

[M105]

Uncheck the squelch.
Check the Tuner AGC.
1.024 samples is fine for single channel monitoring.
FMP24 is the tuner program that comes with DSD+. Using it tuned to your frequency instead of SDR# will allow you to use a TCP connection instead of VB Cable and probably put less load on your CPU.

 

[CanesFan95]

So should the bandwidth be 5k or 15k? And in Windows sound settings, what's the best sample rate and should it be 1 channel or 2 channel? 16-bit or 24-bit? Should I adjust the one under the Recording tab or the Playback tab (or both)? I only see a program called FMP. exe, but not FMP24.

 

[CanesFan95]

Set bandwidth to 15 kHz.

Check out Advanced Decoder Options in DSDPlus.txt in the DSDPlus install directory. Build a batch file to step through the various values as shown and look at the resulting scores. Add the best params to your normal command line and see if you get good audio. Worked for me. Might be necessary per-site or even per-channel.

If you can find someone that will talk long enough, post a 30-second audio clip.

I created a file called Tuning.bat with the following in it:

DSDPlus ? rawAudio.wav -o0 -O NUL -f1 -dr1

But when I run the .bat file, it just flashes a command prompt real quick and then it disappears. DSDPlus never runs. I have a 22 second audio .wav file, but I don't see a way to post it on here.

 

[M105]

12.5 bandwidth is ok.
Audio at 48K samples/sec
16K in Windows leave both at defaults.
FMP is the 1.024k samples version of FMP24. It is fine for what you are doing.

If you want to tune DSD+ I recommend you download dsdtune. DSDTune - The RadioReference Wiki

 

[DSDPlus]

I'm running DSD+ on Windows 7 64-bit, and despite having a strong signal strength, I always get partly garbled audio no matter what I do with the audio settings. Sometimes the audio cuts out alltogether.

Your screen shot shows no decoding errors, but it is not during a voice call. Processor loading goes up during voice calls, so is there a lack of processing power? FMP should use fewer resources than SDRSharp.

 

[adcockfred]

I have intermittent voice problems too. Con+ Sid 330. I ran it on 2 different computer s with fmp on one, doesn't change. Probably a system problem. I guess we will se as things dry out. I am guessing the bands have been closed lately.

 

[AggieCon]

For your tuning test, with the f1, you told it to decode p25. I think you are trying to get DMR, so you need -fr. DSD+ is running, it just finishes its task very quickly. If you want to watch/listen to it, set your output command (-o) to your speakers. Instead of the batch file, type the command in a command prompt, then use the up arrow after each cycle, which will copy your last command, making it easier to fine tune and test again.

Use the 1,2,3 hotkeys while DSD+ is running to switch through the time slots. I'd leave it on 3 (both time slots) unless it is a busy channel.

Your bandwidth in the tuning software needs to cover all of the data. Look at the waterfall, then make sure your bandwidth is a little wider than the hot area.

In your windows playback devices tab, the volume on your virtual cable looks pretty hot, which doesn't correlate to your waveform in the DSD+ spectrum window. Make sure the audio is not clipping.

It does look like you are getting a decode error. Does anyone know the significance of the "cach" error?