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OpenMPT => Help and Questions => Topic started by: game_over on April 01, 2010, 21:29:38

Title: Emulated "surround" has no sound on stereo speaker
Post by: game_over on April 01, 2010, 21:29:38
So, I was just sitting there idly composing songs, sometimes using the beautiful "surround" effect to get that extra kick... and I had the idea of checking it on normal speakers. I had awful suspicions and they were confirmed.

A channel set on that emulated "surround" option in the general tab will give you no output on speakers.

Researching the reason, I found out that the emulated surround inverts the sound wave in the right channel. I also found out that this surround information is not supposed to be saved in an MP3 file, except it gets saved like everything else, FUBAR-ing my compositions. For now I turned off all surround in all my compositions (luckily not too much for now) but seriously... this sucks.

Question is: how do you get that "wider" sound without resorting to a trick that only works in HEADPHONES and even then only due to channel isolation?
Title: Emulated "surround" has no sound on stereo speaker
Post by: Rakib on April 01, 2010, 21:46:57
For full panning effect:
for first note use panning value p = 0
in the next channel, on the same row, panning value=64 and offset value = 001
Title: Emulated "surround" has no sound on stereo speaker
Post by: Saga Musix on April 01, 2010, 21:47:31
err. there's no problem at all with the fake surround on stereo speakers. on a mono speaker, the signal phases will cancel themselves of course, but on stereo speakers, this works as expected. it should even work with mp3. are you using a very narrow stereo spectrum?
Title: Emulated "surround" has no sound on stereo speaker
Post by: game_over on April 01, 2010, 22:01:13
QuoteFor full panning effect:
for first note use panning value p = 0
in the next channel, on the same row, panning value=64 and offset value = 001
Thanks, but what does that exactly do to the sound? What does that "offset value" mean? I want to know to make sure that nothing bad happens in any case. :wink:

Quoteare you using a very narrow stereo spectrum?
Quite possibly. I don't know, haven't used speakers for literally YEARS, because I like headphones better. Regardless, excluding listeners with mono speakers is not fair. The emulated "surround" is not for me then. I'll try Rakib's suggestion when I have time.
Title: Emulated "surround" has no sound on stereo speaker
Post by: Rakib on April 01, 2010, 23:22:51
Please use the help file for question on implications on each effect.

http://forum.openmpt.org/index.php?topic=3405.0

QuoteOxx Set Sample Offset
Starts playing the instrument's sample at the position xx x 256 for 8-bit samples, or xx x
512 for 16-bit samples. If xx is 00, the previous O value will be used.
If xx is greater than the size of the sample, the command (and its note) are ignored,
UNLESS the Old Effects box is checked in Song Properties, in which case the sample is
played from the END of the sample
.
from the help file, page 127.
Title: Emulated "surround" has no sound on stereo speaker
Post by: game_over on April 01, 2010, 23:35:42
Quote from: "Rakib"Please use the help file for question on implications on each effect.

http://forum.openmpt.org/index.php?topic=3405.0

QuoteOxx Set Sample Offset
Starts playing the instrument's sample at the position xx x 256 for 8-bit samples, or xx x
512 for 16-bit samples. If xx is 00, the previous O value will be used.
If xx is greater than the size of the sample, the command (and its note) are ignored,
UNLESS the Old Effects box is checked in Song Properties, in which case the sample is
played from the END of the sample
.
from the help file, page 127.

I'm sorry to be the annoying idiot here... but English, please.
What does that do to the sound? Does it DELAY the sample BY the offset value? Or what? What does it mean?
Title: Emulated "surround" has no sound on stereo speaker
Post by: g on April 01, 2010, 23:40:21
The disadvantage of the method Rakib suggests is that instead of cancellation you may get an unwanted phasing effect in a mono situation. On the other hand I don't really like the fake surround option either, so unless you need it to be a module I'd recommend something like layered sounds with different panning, a stereo delay and some reverb (at least for pads but come on we're talking about pads here aren't we?).
Title: Emulated "surround" has no sound on stereo speaker
Post by: Rakib on April 01, 2010, 23:48:34
It starts to play the sample from the point 256 instead of 0.

If you have 1 sample in 2 channels at the same time with p=0 and p=64 it doesnt work. So that's why one if them need to start at a different times so you can get an stereo effect.
(http://bildr.no/thumb/619665.jpeg) (http://bildr.no/view/619665)
Title: Emulated "surround" has no sound on stereo speaker
Post by: game_over on April 02, 2010, 00:01:24
Quoteunwanted phasing effect
That's better than not having the sound at all.

Quote(at least for pads but come on we're talking about pads here aren't we?)
No. We're talking about some of the basic GM.DLS samples.They are kinda crappy but I believe there's more than meets the eye to them... they are underrated.

Quote from: "Rakib"It starts to play the sample from the point 256 instead of 0.

If you have 1 sample in 2 channels at the same time with p=0 and p=64 it doesnt work. So that's why one if them need to start at a different times so you can get an stereo effect.
OK, thanks for explaining it. :wink:
Title: Emulated "surround" has no sound on stereo speaker
Post by: Saga Musix on April 02, 2010, 07:01:33
I only use fake surround for echos, where it's useful, and mono listeners (I don't care about them at all, someone who listens to my music in mono simply does not deserve something better) just won't get the nice ping-pong echos. For general "spacious sounds", I either recommend rakib's method with a small offset or another similar method, where you would replace the Oxx with an EEx (extreme fine porta) effect.