DAX RX 1.6.17 Audio Crackling

  • 2
  • Problem
  • Updated 2 years ago
  • (Edited)

I have
been running SSDR 1.5.1 successfully on a Windows 7 desktop computer (Core i7, wired Ethernet, etc.).

Since I upgraded to 1.6.17, I have been having intermittent crackling on my DAX RX channels.  This is audible when listening to the audio (selecting “listen to this device” on the Sound control panel) and visible as energy outside the expected bandpass spectrum on the FLDigi waterfall and other audio programs.  The DAX RX audio is bad enough that my digital decoding is very poor.  Audio directly from the radio and from “Remote” is fine.

Here is an image of mild crackling as viewed on FLDigi when the radio is in RTTY mode with 500 Hz bandwidth.  Note the blue to the left and right of the main bandpass. It gets worse.


I downgraded to 1.5.1 and the crackling has gone away.

Has anyone else seen this?  If I am alone, I will try some more troubleshooting after K5P and the VP8’s are QRT.

Note that the DPC latency checker looks very good and I followed full un-install and reboot procedures when upgrading to 1.6.17.

73, Bob, N7ZO

Photo of Bob Wright, N7ZO

Bob Wright, N7ZO

  • 258 Posts
  • 65 Reply Likes

Posted 2 years ago

  • 2
Photo of KM4CQG

KM4CQG

  • 218 Posts
  • 32 Reply Likes
Havent seen this and have used it on digital modes often
Photo of Tim - W4TME

Tim - W4TME, Customer Experience Manager

  • 8670 Posts
  • 3251 Reply Likes
Since you have downgraded, not much we can do.  I recommend that if you have this issue you try one of two things.  Reboot the PC to see if the issue is on the client side of the connection.  If that does not resolve the issue, power cycle the radio to see if the issue is on the radio side of the connection.  If neither of those fixes the issue, I would then look at the network connection.
Photo of Rob Fissel

Rob Fissel

  • 268 Posts
  • 47 Reply Likes
Thought I'd add to perhaps follow Tim's guide to doing a complete uninstall of 1.5 prior to 1.6. Not sure if you did that before originally installing 1.6, but there are major changes to sound card devices, and starting with as clean of a slate as possible might be a good idea. 
Photo of Bob Wright, N7ZO

Bob Wright, N7ZO

  • 258 Posts
  • 65 Reply Likes
An update:

In order to use the Maestro without the upgrading and downgrading (running 1.5.1 on my PC), last week I upgraded the PC to SSDR 1.7.30.  I am happy to report I have so far not encountered the DAX 'crackling' I reported (see the first post in this thread) occasionally with 1.5.1 and consistently with 1.6.

I have been reading the release notes and there is nothing to indicate DAX had been changed since 1.6 (which is why I have not upgraded until now).

Tim, or anyone in the know, can you comment on what might have changed in DAX?  I do not think there were any changes on my PC that could account for this.  I'd like to have some confidence that this was a deliberate and durable change.

73, Bob, N7ZO
(Edited)
Photo of Tim - W4TME

Tim - W4TME, Customer Experience Manager

  • 8670 Posts
  • 3251 Reply Likes
DAX and CAT were completely refactored in SmartSDR v1.6
Photo of Bob Wright, N7ZO

Bob Wright, N7ZO

  • 258 Posts
  • 65 Reply Likes
Hi Tim,

Yes, I know that.  That's what made my problems worse and started this whole thread.  :-)

The question is what was changed between 1.6 and 1.7 that reduced (maybe eliminated) the crackling?

73, Bob, N7ZO