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Audio Monitor – audio after TX band pass filtering preferred

Tony Taddeo
Tony Taddeo Member
edited March 2020 in New Ideas
Currently the TX audio monitor provides pre-band pass filtered audio.  My suggestion is to provide the TX audio after the band pass filtering, to give you a better indication of TX audio.
1 votes

Completed · Last Updated


  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    This has been addressed previously.  The issue is that if the monitor audio is tapped off at the end of the TX signal path, there will be unacceptable latency from the time you speak in the mic to when you hear it in the monitor.  So we tap off the audio at a point before the long latency processes (filters) so you do not have the echo on the monitor.
  • Tony Taddeo
    Tony Taddeo Member
    edited March 2020
    I know the effect of hearing your delayed audio on your brain. Does make it hard to continue talking normally. I note that the recording function also records pre-band pass filtered audio on Tx. No reason why this couldn't be recorded at the end of the TX signal path as this is for play back reasons ? Perhaps have an option of early or late TX signal path recording for those that want the best audio for on-air retransmit and those that want to monitor TX audio.

    Thank you for the explanation.
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    I'll talk the the engineering guys about changing the TX audio tap off point for recording.  I am not sure it can be done easily.
  • K4EAR
    K4EAR Member
    edited May 2014
    I use monitor (ACCY jack) for feeding RTA software to another PC, so a bit of latency is of no concern.
  • K2CB Eric Dobrowansky
    K2CB Eric Dobrowansky Member ✭✭
    edited November 2018

    When recording both sides of a QSO, then playing it back, the tx side is way down in volume as compared to the received side of the recording. Hopefully that can be addressed along with the tx audio being sampled at the end of the chain.


  • N3NER
    N3NER Member
    edited March 2018
    Was there ever an answer to this question?  Having some way of hearing your TX audio in the monitor is the way it should be done.
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    This isn't possible without unacceptable latency.  This is explained in the SmartSDR for Windows User's Guide.  Essentially it takes too much time to process all of the DSP processing (it is the filters that have the longest signal propagation delay).  We provided a way to monitor TX audio using the record and playback feature (also covered in the SmartSDR for Windows User's Guide.

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