I've been trying to isolate an audio distortion problem when running SSDR in remote mode on a tablet PC. It also shows up using Maestro and K6TU's iPad app.
For Maestro users especially, perhaps you can help confirm the distortion by trying the test below. Please listen with stereo headphones:
1) In SSB mode, find a reasonably strong QSO on Slice A. Let's say it's 14.200.000 as an example.
2) Now, activate Slice B and set B to the same freq. as Slice A (e.g., pressing A>B button). Both Slice A and B should read 14.200.000
3) Next, move Slice B up 100 Hz (in this example to 14.200.100). Do you hear severe distortion?
4) Move Slice B back 100 Hz to 14.200.000, does the distortion disappear?
I've noticed the audio distortion does not appear at my Flex 6700 headphone jack. It is only present when using remote audio mode. Yes, hardware and software has been re-set.
*** This test is NOT for users listening at the Flex transceiver's headphone jack ***
Paul, W9AC
Paul Christensen, W9AC, Elmer
Posted 3 years ago
I bet if, during the "distortion", you mute either slice the distortion will magically disappear. Sounds like what you've set up is a demonstration of how to generate phase distortion using a Maestro.
The reason you don't usually hear it is that the 2 slices' audio channels are kept separate in the radio and moving the frequency(phase) slightly moves the stereo image around between the 2 speakers. If you take those two signals and mix them to a single speaker, however, the phase differences generated as you move the frequency of one slice will add or cancel as you move and that is the distortion you hear. Some audio frequencies adding while others are cancelling really chops up the bandpass.
I don't have a Maestro but I have done just as you described before I changed my setup at home to full 2-channel instead of a monaural mix.
The reason you don't usually hear it is that the 2 slices' audio channels are kept separate in the radio and moving the frequency(phase) slightly moves the stereo image around between the 2 speakers. If you take those two signals and mix them to a single speaker, however, the phase differences generated as you move the frequency of one slice will add or cancel as you move and that is the distortion you hear. Some audio frequencies adding while others are cancelling really chops up the bandpass.
I don't have a Maestro but I have done just as you described before I changed my setup at home to full 2-channel instead of a monaural mix.
Paul Christensen, W9AC, Elmer
That's correct Bob. And to Jim's point, the distortion is maximum when AF level and AGC-T are the same between Slices A and B.
It's the first time I've heard distortion in split mode and to repeat, the test produces clean audio at the transceiver's headphone jack.
Paul, W9AC
Tim - W4TME, Customer Experience Manager
I have added this report detail to the open HelpDesk ticket #3619 regarding distorted Maestro RX audio.
Paul Christensen, W9AC, Elmer
Thanks, Tim!
Paul, W9AC
Steve - N5AC, VP Engineering / CTO
Paul Christensen, W9AC, Elmer
Steve - N5AC, VP Engineering / CTO
KY6LA - Howard, Elmer
The issue is how do you identify local remote audio vs remote remote audio.
A lot of remote Apps use remote audio. And bandwidth is an issue when Remoting remote.
Nerd Knob?
A lot of remote Apps use remote audio. And bandwidth is an issue when Remoting remote.
Nerd Knob?
(Edited)
Yes, I think the "easiest" solution would be to make it user selectable, either with a nerd knob or with double buttons --- [LAN Remote] [WAN Remote]
Ken - NM9P
Ken - NM9P
Paul Christensen, W9AC, Elmer
">I think the ultimate solution here is to allow for uncompressed audio locally. It's not terribly complicated to do this and it's actually easier on everything but the network. Then the user would have an option for the tradeoff between ultimate audio quality and network bandwidth. Do you agree that this would be a good solution?"
Steve,
I think you mean remotely, not locally? Flex audio is superb when listening to the 6x00 hardware's headphone jack. I call that local audio. By contrast, "remote audio" as used in the upper right corner of SSDR, or using Maestro, or SSDR-ios, is what I refer to as remote audio and that's compromised at the moment with these subtle audio distractions.
So, I think the ability to either let OPUS truly adapt to available network bandwidth -- or allow the user to select from a small menu of compressed and uncompressed CODECs just like RemoteRig, RemAud and IP-Sound is the way to go as Flex gets closer to SSDR version 2.0. Of course, a choice of "Auto/Manual" would be even better.
Paul, W9AC
(Edited)
Steve - N5AC, VP Engineering / CTO
Sorry for the confusion-- I mean use uncompressed audio in your LAN, compressed audio on the WAN
KY6LA - Howard, Elmer
You will still need a nerd switch until V2 because WAN via VPN looks like LAN to SSDR
Perhaps one could select audio as LAN Remote and WAN Remote as per Ken's suggestion.
Perhaps one could select audio as LAN Remote and WAN Remote as per Ken's suggestion.
(Edited)
