Using a Dolby Digital upmixer for stereo? How dare you!



OK, So I have been doubting for a long time to post this as my ideas and conclusions have been the complete opposite from anything I’ve ever read on the Internet. However, I have recently (unsuccessfully) tried some popular alternatives to attaining ‘audio nirvana’ and was so disappointed with the results that I knew my method has some merit.

Here’s the thing: I use a sound card (Asus Xonar HDAV) on my PC to upmix stereo sound to Dolby Digital (at 640 kbps) and send that signal via Toslink to my AVR (Onkyo TX-RZ710) and finally to my Paradigm Mini Monitors and BK XXLS400 subwoofer. Literally anything that I play, be it mp3s or flacs on the pc itself or streaming online, such as Deezer, gets routed through the sound card and is upmixed. I even ‘flavour’ multi-channel sources by setting input channels to 6 channels and using the DD upmixer to improve the sound quality.

By now I’m expecting you to wearily shake your head thinking this must be the worst way to enjoy stereo sources in the world, using some marketing tool to downgrade the purity of the signal and what not. I can’t blame you at this point; the whole of Internet would agree with you! I’ve seen countless Internet ‘experts’ posting bitrates and sample frequencies to show I must be wrong (because we all know that 44.1khz vs 192 khz makes a huge difference, right? Right?) and audiophiles claiming that any distortion of any signal makes it worse and the ‘correct’ way forward is using the ‘pure mode’ on your AVR…. and don’t you dare disagree!

But I do disagree. Ever since I’ve gotten into audio I’ve used an HTPC to listen to music and ever since I’ve used an HTPC I’ve used a sound card to do the work. Bit of background here; this all started in 2002 with a Hercules Gamesurround Fortissimo which I connected with RCA-connectors to several old amplifiers connected to loudspeakers. This all changed when I bought the Asus Xonar D2/PM in 2009 which made a huge impact on the music I played. Such an impact, in fact, that not soon after I bought my first AVR, the Sony STR-DG700. This AVR would take anything, including Toslink and as the sound card offered this whole new Dolby Digital Live! and DTS Neo:pC upmixing technology I wanted to try that out too. In the meantime I haven’t looked back. Yes, I have swapped the D2 for the HDAV (and also gotten a Sound Blaster Z to compare it with),but the principle stayed the same.

Skipping ahead to 2018: by now I had read so much about room correction that I wanted to try this myself. So, I bought myself a setup to make measurements and make adjustments to my system accordingly. Did this make the sound card obsolete? Nope, as Equalizer APO works in tandem with the Xonar HDAV and lets you make any convolution filter you’d like. One thing I did find difficult was how to make sure no bass (80 hz and below) was sent to my main speakers.

That’s why I recently bought a Minidsp 2x4 as I was interested if the Minidsp could make the system sound better by redirecting all bass to the subwoofer, leaving the speakers to do the rest. As you might now, Minidsp does not accept any dolby digital signal, so this was a chance to use the analogue out on the sound card, attach it to the minidsp, set it up correctly and send that signal to the AVR and upmix it there. And the results? In a word? Disappointing. In fact, I was really surprised by how bad it sounded compared to the DD-upmixer on the sound card, as everyone keeps raving about Minidsp. The sound didn’t reach out into the room as much, the speakers sounded thinny and the subwoofer seemed to blow everything away (even though I set it to -20DB and dialed it in only a quarter).

After these disappointing results I thought it was time to write a post online. I guess to share my thoughts and results with you and maybe, maybe convince you to try it for yourself. I know it may sound unorthodox, but it might do the trick for you as it does for me.

Oh, and comments are more than welcome! However, if you’re planning to give me the whole ‘bitrates and frequency rates’ story again or the ‘how dare you change anything to the sound the producer wanted to reproduce’ story I’d advise you to save your breath… at least until you’ve tried it my way!

Cheers and thanks for reading!

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