FM mode low audio out

[Cosmo1stgen]

Well as I venture to use Thetis instead of MRX I come across new issues. This time its FM mode. I occasionally use 6 meter repeaters and have a 2 meter transverter. On FM I am getting complaints of low audio. Just for fun I cranked the audio gains to the max in vac and was told it was maybe 50 percent better but still low. I remember having this issue in power sdr MRX and the fix was in the dsp tab under FM clicking the preemphasize check box. Unfortunately I tried this in Thetis and it doesn’t seem to work. Still low audio. SSB is perfect so not messing with that. I do have an FM tx profile. Any ideas?

[KA1GXR]

Make sure your deviation is 5 khz. 2.5/5khz button on main screen lower right to right of microphone level slider. 2.5 will sound too low.

Tom
KA1GXR

[Cosmo1stgen]

Tom,

Thanks. I do always run it at 5khz. I have had the same setup in powersdr mrx for several years. Switching to thetis now. I don’t think that pre emphasis setting is working. That’s what fixed it in the past in MRX. I run the mic gain for ssb at 6 in VAC. On FM I have it at 40 to even be copy able.


Ryan
kK6DZB

[FM5GB]

Hi

Concerning FM mode I noticed a strong increase in processor load in this mode versus all others. This may cause frame drops and audio glitches. This is more obvious on high sample rates. Do you have the same experience ?
Concerning you low audio output you should increase your MIC gain enough to hit just over the 0 dB mark on your TX meter while speaking. If you don't achieve this you may increase Max Mic Gain in Setup/Transmit tab. (I use the Line In source with a balanced audio chain, but the setting should be the same with Mic In input).

73 Phil FM5GB