Re: 5.1 Revisited

Maverick wrote on 7/28/2003, 6:26 PM
Hi

Can't find anything on my query so hopefully some of the better knoleged people can help.

I have added a stereo audio music track and then copied it to another (Vegs 4 set for 5.1). This second track I have set to LFE. I am getting what I would call unexpected results but can't actually find further documentation.

Basically I can tell that the LFE channel does only contain the frequecies lower than the cut-off but I would have expected the remaining track to lose these frequencies but they don't. On this basis I can't see any reason to actually have a separate track. Has anyone got further advice to add?

Thanks.

Comments

SonyDennis wrote on 7/31/2003, 4:02 PM
The LFE channel does go through a low-pass, per Dolby specifications. The full-range channels are FULL RANGE and don't automatically high-pass to "compensate" for having an LFE track. A playback system is not even requried to play the LFE track, and your production is still supposed to sound good (for example, the analog 2-channel outputs are usually downmixed from the 5 main channels, and not the LFE channel). Also, a given playback system is allowed to mix mains into the subwoofer output in addition to the LFE channel (one of many reasons why LFE and subwoofer are not synonyms).

LFE is supposed to be used for effects, not bass reinforcement. Most music 5.1 mixes properly don't use it.

Dolby has some great whitepapers on this stuff on their website, I encourage you to check them out.

///d@
Maverick wrote on 7/31/2003, 4:07 PM
Thanks
Maverick wrote on 7/31/2003, 5:10 PM
From what I have read I have a better understanding of LFE and 5.1 but I am still a little confused.

Apart from altering the volume and adding the same effects as you can on the surround track there seems to be little else you can do with this track or am I missing the point still.

Also, is there any benefit in copying an audio track 5 times giving 5 surround tracks and the LFE to set individually or just setting the pan, etc. effects on the one track.

Thanks for any advice.