SDRplay Community Forum

Lately I've been having an issue with the audio cutting in and out about every second or two. I was not having that problem initially, but now it is occurring frequently. Any ideas what would cause this issue? Is seems to happen whether I use SDRUno or SDR Console. All of this SDR stuff is new to me, so I am just kind of playing in the dark here.

I am using an old laptop with Windows Vista on it, 4gb of memory and a dual core AMD 2.1 ghz processor. I don't know what kind of sound chip it uses.

I managed to fix the problem, but I have no idea how I did it. This SDR stuff is totally new to me so I'm learning as I go. What I did was, on a whim, increased the Decimation to 8. I don't know why I did so...I just thought I would give it a try. That stopped the audio cutting in and out. I have no idea why it stopped the issue. I don't even know what is Decimation, but it cured the problem. What I really need are some reading materials besides just a users manual that explains what are some of the terminology and function of SDR in general.

Hello Royce,
You problem is caused by the CPU hitting 100% on at least 1 of its cores. Applying decimation reduces the final sample rate prior to demodulation and also reduces the amount of visible spectrum. One possible reason for your CPU 'clipping' might be if you were using zoom in the SP1 window to allow you to see the spectrum closer in. This increases the FFT size to give better resolution and as a consequence leads to greater CPU usage. If you want to zoom in on a smaller section of spectrum, reducing the sample rate (SR) and/or increasing the decimation factor is a good way to do it.

Sincerely

SDRplay Tech_Support

Thanks for the explanation. I appreciate it since SDR is all new to me and I used to the old analog type radios. I probably did zoom in on SP1 at some point as I was trying out the various controls and options just to try to understand what would happen when I used those features.

If I had been using a more powerful computer, such as one with a faster CPU speed and maybe a quad core CPU would that have made a difference or would it still overload that kind of a CPU?

Hello Royce,
A more powerful CPU would certainly help.

Sincerely

SDRplay Tech_Support

This can also be caused by mismatched audio sample rate settings. For example using 44.1 kHz as the audio out with a native sampling rate of 48 kHz. You can avoid this problem by making sure all of the audio settings are using the native sample rate for your audio device.

Thanks,
-CAS

I'm having the same problem of audio dropping out.
If I set up a Final SR (using the SR(MHz) and DEC controls) of greater than 3000000, then my audio breaks up.
My system is:-
Win10
64 bit on X64 processor
Intel core I7-4700HQ CPU @2.40GHz
8.00 GB RAM
For any settings resulting in a Final SR above 3000000, the Sdr: reading does not exceed 20% and the Sys: does not exceed 25%.
Any assistance in solving this issue would be greatly appreciated.

what we need here is a raw thru-put test app like what airspy tools provides for Airspy but for Mirics chips.
lots of USB 2.0 pipes are dropping bits by the time we get to 5 (million samples/second) msp.. Its a rare system that lets you get to 10msp without loss (audio drop out). thats 60 - 120 million bits/second
RSP is 12 bits/sample
Internally many of the controllers are shared.

My Asrock x370 Rizen 1700 drops bits.. finding an onboard controller with an open pipe to the CPU is hard.

Good luck

I omitted to mention it is an RSP2 running under version 1.13 of SDRuno.

I can confirm what CASCmptrski said in his post. I had an annoying 1 second drop out of audio every 20 seconds. My resource useage bars were way low so it wasn't cpu overload. I checked my soundcard settings in control panel and sure enough, it was set to 48khz. I switched it to 44.1khz and the dropout went away.