Bi-amp using Front-Width channels adversely affects surround
May 19, 2020 12:32:52 GMT -5
megash0n likes this
Post by markc on May 19, 2020 12:32:52 GMT -5
This is pertinent to the XMC-2 and RMC-1/1L (But not the XMC-1)
There is an issue with both the old 1.9 firmware and in the new 1.10 firmware with regards to using the Bi-amp speaker setting using the Front Wide channels which adversely affects the surround sound detection / processing. This affects both Dolby and DTS sources.
Situation affected: Speaker setup allows the Front Width channels to be re-purposed instead to bi-amp the fronts, to save using Y-cables. This appears to work (and does indeed duplicate the L & R into the FW outputs, but causes undesirable issues as the processor still seems to think there are height channels in use and doesn’t perceive still a simple 5.1 / 7.1 system
Problem: configuring Front Wides as Bi-amp definitely affects the way the XMC-2 detects surround sources and offers / applies surround modes.
I think the surround algorithms still perceive that height channels are in use even though they are not, Probably due to an incorrect flag somewhere, and incorrect surround detection and processing is subsequently applied.
I have a 7.1 system.
with Auto set for the 5.1 Surround mode in the Input Setup Menu: (because I want 5.1 movies to be expanded to 7.1)
(see other posts From yesterday in the RMC forum as to why using "Surround" or "Direct" or "Last Used" doesn’t correct this issue)
With normal use and WITHOUT reassigning Front Height to Bi-amp.:
-5.1 Dolby sources are upmixed to 7.1 using the "Dolby Surround" mode and used Dolby Surround Upmixer. This is good, and normal behaviour.
-7.1 Dolby sources are played with the "Surround" mode and left untouched. This is good, but see below for what happens with bi-amping
-5.1 DTS sources are upmixed to 7.1 using the DTS Neural X mode. I have issues about the Neural X effect on all the channels as it doesn’t just expand the sides to the sides+rears for 7.1, but the detection and intention to upmix are, at least, correct.
7.1 DTS sources are played with the "Surround" mode and left untouched. This is Correct and good, but see below for what happens with bi-amping.
WITH reassigning Front Height to Bi-amp:
-5.1 Dolby sources are upmixed to 7.1 using the "Dolby Surround" mode and used Dolby Surround Upmixer. This is correct, although I can’t tell if any height processing is done.
-7.1 Dolby sources are played with the "Dolby Surround" mode!. This is potentially bad!, no additional processing is needed for 7.1 to 7.1 and I worry that processing is occurring although it doesn’t sound different than manually selecting "Surround"
-5.1 DTS sources are upmixed to 7.1 using the DTS Neural X mode. Again, I have issues about the Neural X effect on all the channels as it doesn’t just expand the sides to the sides+rears for 7.1, but the intention to upmix is correct. I don’t know if any height processing for non-existent heights is occurring, and DTS Neural X on the XMC-2 just sounds so bad that I can’t stratify levels of badness.
-7.1 DTS sources are unfortunately now also played with the "DTS Neural X" mode when no additional processing is required for 71 to 7.1. This is EXTREMELY BAD, mostly because of the volume decrease across all channels with Neural X along with the apparent smearing of the front channels. The action of Neural X aside, it should not be engaged for 7.1 to 7.1
For the time being I have disabled Bi-Amping and done it with cables, as it does not work as it should in the aspects above, and I would strongly advise this if you have a 5.1 or 7.1 system.
It is not possible to know what the upmixers (both Dolby Surround and DTS Neural X) are doing with regards to height processing firstly, and secondly, especially with DTS 7.1 sources, the engagement of Neural X for 7.1 sources to 7.1 speakers is markedly deleterious for sound processing, adding nothing and taking lots away.
There is an issue with both the old 1.9 firmware and in the new 1.10 firmware with regards to using the Bi-amp speaker setting using the Front Wide channels which adversely affects the surround sound detection / processing. This affects both Dolby and DTS sources.
Situation affected: Speaker setup allows the Front Width channels to be re-purposed instead to bi-amp the fronts, to save using Y-cables. This appears to work (and does indeed duplicate the L & R into the FW outputs, but causes undesirable issues as the processor still seems to think there are height channels in use and doesn’t perceive still a simple 5.1 / 7.1 system
Problem: configuring Front Wides as Bi-amp definitely affects the way the XMC-2 detects surround sources and offers / applies surround modes.
I think the surround algorithms still perceive that height channels are in use even though they are not, Probably due to an incorrect flag somewhere, and incorrect surround detection and processing is subsequently applied.
I have a 7.1 system.
with Auto set for the 5.1 Surround mode in the Input Setup Menu: (because I want 5.1 movies to be expanded to 7.1)
(see other posts From yesterday in the RMC forum as to why using "Surround" or "Direct" or "Last Used" doesn’t correct this issue)
With normal use and WITHOUT reassigning Front Height to Bi-amp.:
-5.1 Dolby sources are upmixed to 7.1 using the "Dolby Surround" mode and used Dolby Surround Upmixer. This is good, and normal behaviour.
-7.1 Dolby sources are played with the "Surround" mode and left untouched. This is good, but see below for what happens with bi-amping
-5.1 DTS sources are upmixed to 7.1 using the DTS Neural X mode. I have issues about the Neural X effect on all the channels as it doesn’t just expand the sides to the sides+rears for 7.1, but the detection and intention to upmix are, at least, correct.
7.1 DTS sources are played with the "Surround" mode and left untouched. This is Correct and good, but see below for what happens with bi-amping.
WITH reassigning Front Height to Bi-amp:
-5.1 Dolby sources are upmixed to 7.1 using the "Dolby Surround" mode and used Dolby Surround Upmixer. This is correct, although I can’t tell if any height processing is done.
-7.1 Dolby sources are played with the "Dolby Surround" mode!. This is potentially bad!, no additional processing is needed for 7.1 to 7.1 and I worry that processing is occurring although it doesn’t sound different than manually selecting "Surround"
-5.1 DTS sources are upmixed to 7.1 using the DTS Neural X mode. Again, I have issues about the Neural X effect on all the channels as it doesn’t just expand the sides to the sides+rears for 7.1, but the intention to upmix is correct. I don’t know if any height processing for non-existent heights is occurring, and DTS Neural X on the XMC-2 just sounds so bad that I can’t stratify levels of badness.
-7.1 DTS sources are unfortunately now also played with the "DTS Neural X" mode when no additional processing is required for 71 to 7.1. This is EXTREMELY BAD, mostly because of the volume decrease across all channels with Neural X along with the apparent smearing of the front channels. The action of Neural X aside, it should not be engaged for 7.1 to 7.1
For the time being I have disabled Bi-Amping and done it with cables, as it does not work as it should in the aspects above, and I would strongly advise this if you have a 5.1 or 7.1 system.
It is not possible to know what the upmixers (both Dolby Surround and DTS Neural X) are doing with regards to height processing firstly, and secondly, especially with DTS 7.1 sources, the engagement of Neural X for 7.1 sources to 7.1 speakers is markedly deleterious for sound processing, adding nothing and taking lots away.
