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AC3Filter Downmix DTS/DD to Stereo for DacMagic

gazdude

Established Member
Just putting the finishing touches to my new stereo system for use with my HTPC.

I previously had it hooked up to an AV amp with 5.1, now I need to process 5.1 DTS and DD soundtracks to stereo to be fed via optical into a DacMagic.

Does anybody know the best settings in AC3filter to achieve this? I tried setting the output to 2 channels but only seemed to get background sounds and not the full 'mix'. Do I need to play with the matrix options and what do they actually do?

Thanks in advance for any advice!

At least I seem to have managed to get foobar to use WASAPI to get lossless playback of flac files.
 

jameson_uk

Prominent Member
Why do you want to downmix? If you do that you will only get stereo out there other end. I did look at the DACMagic a while ago and does it not have a SPDIF passthrough so you can send DD/DTS through to your amp as DD/DTS
 

gazdude

Established Member
I'm actually migrating from an all in one one sort of AV system to a decent stereo system. The Dacmagic can't process DD/DTS to send to my new stereo amp as an analogue signal.

So I guess the processing would have to be done on the pc end via ac3filter or ffdshow?
 

Stephen Neal

Distinguished Member
I'm actually migrating from an all in one one sort of AV system to a decent stereo system. The Dacmagic can't process DD/DTS to send to my new stereo amp as an analogue signal.

So I guess the processing would have to be done on the pc end via ac3filter or ffdshow?

Yep - though Windows itself will do a DD5.1 to PCM2.0 downmix (though it won't do anything with DTS) in a normal set-up - though if you're trying to bypass as much of Windows audio stuff as possible this might not be relevant?
 

jameson_uk

Prominent Member
I'm actually migrating from an all in one one sort of AV system to a decent stereo system. The Dacmagic can't process DD/DTS to send to my new stereo amp as an analogue signal.

So I guess the processing would have to be done on the pc end via ac3filter or ffdshow?

Ahh ok so you only have a stereo setup. I thought you still had the AV amp (I am sure what I looked you could connect the PC via USB and then connect DAC to AV amp and for DD/.DTS you could get it to bypass the actual DAC and pass the input out through the SPDIF connection to amp.

Do you really want stereo output for video content? I would actually have stereo audio out of the (not great) tv speakers as when output via stereo speakers everything (particularly vocals) just seems too distant and removed from the visuals???

If you do want DD/DTS output as stereo you probably need to set your windows speaker settings to stereo speakers and then setting AC3Filter to output as 2.0 and turn off all passthrough options
 

Stephen Neal

Distinguished Member
Do you really want stereo output for video content? I would actually have stereo audio out of the (not great) tv speakers as when output via stereo speakers everything (particularly vocals) just seems too distant and removed from the visuals???

Hmm - I've watched broadcast TV through a reasonably decent stereo system since about 1990 when I first got a NICAM decoder (self-installed in a VHS HiFi machine) - even when a student watching a 14" 4:3 TV... The improvement over most TV speakers means I'd be unlikely to go back - and I didn't have any major problems with the relative picture size vs soundfield size difference after a short period.

My main HTPC viewing environment is now 5.0 (don't have a sub-woofer) - but my secondary HTPC is still stereo Hi Fi speakers (though now fed SPDIF rather than analogue).
 

jameson_uk

Prominent Member
Hmm - I've watched broadcast TV through a reasonably decent stereo system since about 1990 when I first got a NICAM decoder (self-installed in a VHS HiFi machine) - even when a student watching a 14" 4:3 TV... The improvement over most TV speakers means I'd be unlikely to go back - and I didn't have any major problems with the relative picture size vs soundfield size difference after a short period.
Just me then :rolleyes:

Years ago I shared a flat with a bloke who had a reasonably decent set to B&W stand mounted speakers and a Marrantz amp. I went out and bought a Yamaha DSP-E492 processor which acted as a three channel amp for centres and rears and some KEF speakers. I had a DVD player with a Dolby Digital decoder onboard, everything was hooked up via analogue connections and all was good :) He moved to London and I was left without any front amplification. As a stop gap measure I ended up with an entry level Yamaha amp and a pair of KEF floorstanders (which I have only just replaced a few months ago).

I did a fair of testing back then with my 4:3 29" Sony CRT. I think part of the issue was probably that the house I was living in at that time had a big front room and the fronts were a fair distance from the TV and the KEFs are very precise in terms of where the audio is coming from.

I did a quick test last night; now I am using B&W M1s and a 42" plasma with the speakers basically touching the side of the TV and it was not too bad but still to me sounded a lot better when Pro-Logic was used with vocals sounding like they were coming out the TV (well centre speaker) then when played in stereo. This setup is a little compromise since I have moved in with the misses and speakers are not the greatest but I did feel it sounded a lot better through the centre and fronts than just the fronts. I guess it probably did still sound better through the fronts than through the TV (perhaps I will try this tomorrow)
 

gazdude

Established Member
Moving from a Samsung X30R to a NAD C370 with Monitor Audio RX1 speakers is making a world of difference even with just normal TV.

I've managed to get AC3Filter working to downmix DTS/DD to stereo via optical. There are a variety of matrix settings which affects how the downmixing works to varying degrees of success. I'll have to tinker about with these as there doesn't seem to be much info on the 'net regarding this!
 

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