RSPDuo and two VAC streams

[MTG]

Having set up a single tuner of my Duo with the help of Roger (see Optimisation of IF and RF gains) I moved on to using the two tuners in Normal Dual mode. I then spent a day trying to get the other tuner working in the same way. I used VB VACs for streaming the output of the two tuners to separate applications. The problem I have is that despite setting the two up identically I could not get the same audio output levels. Everything indicated on the two instances of SDRUno look OK.

SDRUno ScreenShot5.gif (146.58 KiB) Viewed 10663 times

I am running Windows 7 and ASIO4All drivers.

Swapping the VACs swaps the output levels. Running the Duo in single mode and swapping the VACs gives the same Input level to the VACs. The same is true when using either tuner.

[Roger]

You need to bring up the EXW windows for both tuners. The AGC level should be at the default of 100. You will have to adjust this level and the volume control for your application. In Audacity 0 dB means that the A to D samples are at maximum before overload (i.e. the most significant bit is being activated)

agc.PNG (52.68 KiB) Viewed 10635 times

[MTG]

Oh! I had thought that highlighting the RX Control AGC button turned off the AGC and rendered all AGCs inoperative! How does that work then? When I looked at the EXW I found the settings were different and adjusting them both to the same (100) position and still can't balance the inputs to Spectrum Lab

I need to put on a cold compress - there are too many adjustments
For RSP Duo: IF Gain, RF Gain, Volume, EXW AGC
For Windows: Sound Playback VAC A Input and Main Volume and Recording VAC Output and Wave In Volume.

All that doubled up for a Duo ... but I will get there .... hopefully

Edit: Done! levels match to about a dB which is good enough for now.