Remove rear channels echoing when upmixing to 5.1

2023-06-19 08:37:23

Hi there,

I recently got a nice loudspeakers+amp setup. I'm using foobar 2.0. When playing music without any DSP activated, everything is fine but, when I activate the 5.1 upmix, I get a very disturbing effect on the 2 rear loudspeakers: voices are not as loud as in the other speakers and there is a weird "muddy" echo going, rendering the whole experience unpleasant.
To be sure that those rear loudspeakers are not broken, I also tested the "move stereo to rear channels" DSP. And then voices became clear and loud in the rear, no sound from the front loudspeakers. So I can only conclude that this muddy echoing is an intended effect of the 5.1 upmix.

The 5.1 upmix DSP doesn't have any options. Is there an alternative DSP with options to control "voices clarity"? Is the source code of those DSP available somewhere so I can alter the code myself for this DSP to fit my needs if no alternatives are available?

Re: Remove rear channels echoing when upmixing to 5.1

Reply #1 – 2023-06-19 12:24:08

The DSP copies the front channels to the surround channels as is. They are 100% bit-for-bit copy of the left and right front channels.

Re: Remove rear channels echoing when upmixing to 5.1

Reply #2 – 2023-06-19 16:15:49

I see so the culprit is my amp doing some kinds of shenanigans on the surround channels when every channel is used? I'll try to fiddle with it then. Thanks for the reply.

Re: Remove rear channels echoing when upmixing to 5.1

Reply #3 – 2023-06-20 20:57:13

Ok, indeed it was my amp doing some "AI" stuff by trying to improve the sound... I had to find the mode to get a straight rendering of the sound channels. What got me here is that there are only 3 buttons on the front pannel itself but everything is hidden on the remote control or in menus only accessible from this remote control... I should have checked this first, sorry for this useless thread :p