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Difference in Audio Rendering

Hi all,
This is my first post at hydrogenaudio. Apologies if my question is too basic but I can't seem to figure it out.
I was listening to the audio clip at
http://www-mmsp.ece.mcgill.ca/documents/audioformats/wave/Samples/Microsoft/6_Channel_ID.wav

There is a bass note that is played at the end of the clip.
I could hear the bass part when I listen to it using Google Chrome, but when I use Internet Explorer, it opens up WIndows Media Player, and the bass part is not audible.
I am using my earphones to listen to this clip, so basically the 5.1 clip is getting downmixed to 2.0 here.
From this observation, I have come to the conclusion that the rendering of audio in both the cases is different. Is that so? What exactly is happening here? Or am I missing something very basic here?

Re: Difference in Audio Rendering

Reply #1
Just guessing, but check your control panels for a place where you can say how many speakers you have. Wherever you find this setting, your chosen speaker setup should match whatever you normally listen with—headphones obviously being just a pair of stereo, full-range speakers.

On your system, it may be in your normal Sound control panel (the content of which may be influenced by your soundcard drivers). On my Lenovo desktop, it was somewhere else: buried under a different control panel called Lenovo HD Audio Manager.

No guarantees, but it's a place to start looking.

Re: Difference in Audio Rendering

Reply #2
I can confirm that. First look if the sound playback device is stereo and full range (box should be checked at properties). If that does not help then check if the sound card is set to 24/44.1 or whatever the sample rate of the audio is (that clip seems to be 44.1) to rule out resampling, or play that file through Foobar WASAPI (probably too advanced for you at this stage).

Re: Difference in Audio Rendering

Reply #3
Quote
I am using my earphones to listen to this clip, so basically the 5.1 clip is getting downmixed to 2.0 here.
The LFE is not supposed to be included in the stereo downmix (at least that's the case with Dolby 5.1 on DVDs).    That bass tone is only in the LFE channel so Chrome is doing it wrong.

The other 5 channels are supposed to contain the "normal" bass so with a normal 5.1 channel soundtrack you shouldn't be missing the bass when you play it back on a 2-channel stereo system.   

The "point one" Low Frequency Effects channel is only supposed to contain extra bass for booms & explosions, etc. which is sent only to the subwoofer

...On most home theater systems with "small" surround speakers, bass management is used to send the normal bass from the 5 surround speakers plus the low frequency effects channel to the subwoofer.

Re: Difference in Audio Rendering

Reply #4
The LFE is not supposed to be included in the stereo downmix (at least that's the case with Dolby 5.1 on DVDs).    That bass tone is only in the LFE channel so Chrome is doing it wrong.

Okay, but if that is the case, isn't this bad design? Because at the end of the day, I would just like to have a better audio experience, whatever way it might be. If chrome is including the LFE channel in the stereo downmix, then I'd probably say that it's a good thing, because I got even better sounds with that.
Any specific reason for not including the LFE in the downmix? Is there an assumption that the stereo setup will not be able to handle such low frequencies?

Re: Difference in Audio Rendering

Reply #5
In Windows check playback devices (right click the tray speaker icon) - configuration for your playback device and try to disable all enhancements, also check the control panel of your soundcard if the driver installs such a thing.

If your stereo speakers are full-range (and you may need to configure them as such) then I think LFE should be in the stereo downmix. If they are not then LFE should not be in the downmix.


PS: Isn't Chrome using DS or does it do some mixing itself? Or maybe it's using shared WASAPI?
Not going to install Chrome so I cannot check myself.
"I hear it when I see it."

Re: Difference in Audio Rendering

Reply #6
Quote
Okay, but if that is the case, isn't this bad design? Because at the end of the day, I would just like to have a better audio experience, whatever way it might be. If chrome is including the LFE channel in the stereo downmix, then I'd probably say that it's a good thing, because I got even better sounds with that.
Any specific reason for not including the LFE in the downmix? Is there an assumption that the stereo setup will not be able to handle such low frequencies?
Look page 12, the 1st paragraph, of the Dolby Metadata Guide:   "In all downmixes, the LFE channel is not included."

I can only guess why...   It could be to preserve headroom and/or because it's assumed that regular stereo speakers can't reproduce it.

Quote
I got even better sounds with that.
Remember, the other 5 (or 7) channels are supposed to contain the normal bass and that is included.   You shouldn't be missing anything with music, because the music bass isn't supposed to be in the LFE.   You're also getting the "normal" bass from sound effects.   You should only be missing that extra wall-shaking bass from special effects.

Re: Difference in Audio Rendering

Reply #7
Thanks everyone for your responses.

@DVDdoug, thanks for the link to the Dolby Metadata Guide. Now I feel bad that the rendering for the downmixed audio is not standardized. Most sound engineers out there use Audacity as their default player to listen to any audio. And even Audacity is playing the LFE channel in the stereo downmix. Do you have any suggestions for a better media player?

 
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