Need Help!!! About 5.1 Music!!!

Question

Hello Creative Card users, I recently got a SoundBlaster Live! 24-Bit and a 5.1 surround sound. It is interesting about the CMSS 3D feature, but I was curious about this question.
Is there any way I can convert my MP3's to 5.1 Surround Sound?
Thanks

Answer 1

I use several ways, several apps, to create 6-channels files, so it would be to long for me to explain them all. Besides, there is a lot of information on the net on how to create sourround sound audio files, try for example http://www.doom9.org. They have a forum dedicated to audio encoding, along with some guides on "how to" for multichannel sound.
But just to help you not get overwhelmed and confused with all the info outthere, there are some basics that u should know:
UPMIXING: means taking a "X number of channels" file to a "Y number of channels" file where Y > X.
This means that is a basic creation of a new audio file from from an existing audio file (source) in wich the new file has more channels than the source file. Now, the way of adding those extra channels is in what the upmixing techniques diverge.
And DONWMIXING means the exact opposite.
5.1: means 5 full range channels (20 to 20.000 Hz) plus 1 low frequency channels (1 to 120 khz). This .1 channel carries basically base sounds that add up an extra punch to the base information in the audio. Since they´re low frequency sounds, it´s called LFE (Low requency Effects) channel.
The .1 channel IS NOT a subwoofer channel, since the 5 full range channels carry low frequency sounds that are reproduced also by a subwoofer (if the speaker asigned to that channel has a subwoofer).
6-channels means 6 channels whether they are 5.1 kind of files or just 6 full range channels kind of files.
Matrix vs. Non-Matrix: a matrix-encoded audio track means that a number of X channels (for ex. 6-ch)was downmixed using a series of equations that create an Y channels file (for example 2-ch).
That means that the 2-ch file is matrix-encoded and by applying the inverse of the downmixing matrix (what would be an upmixing matrix) u can get back a (not exactly as original but very similar) 6-ch audio file.
Non-matrix audio files means that there is no equation applied mixing of more channels than the original.
2-ch is NOT synonimous of matrix-encoded and 6-ch is NOT synonimous of non-matrix-encoded. For example: if
the original file had 12 channels and u downmixed it to 6 channels by eliminating 6 others, then there is no matrix applied to the resulting 6-ch file, u just deleted 6 of the 12. On the other hand, If u create a 6-ch file where every channel is the sum of a par of channel of the original (Ch1 + Ch2 = New Ch1, Ch3 + Ch4 = New Ch2, etc.) then there is a mtrix been applied in the downmixing, wich would be "take the 6 pairs of channels from the 12-ch file and and create a single channel for each channel pair where every new channel is the sum of the 2 channels in each pair". Understanding this,u can automatically create your own matrixes.
Dolby Prologic II, wich is the one of the most used standards for 2-ch matrix-encoded audio, uses the folloing matrix for downmixing from 6-ch (5.1) file to 2-ch file:
<<--- Reference
Lt = Left total
Rt = Right total
L = Left
C = center
R = Right
SL = Surround Left
SR = Surround Right
LFE = Low Frequency Effects Channel
1 = 100 %, then 0.7071 = 70,71 % (of the maximum dB), or 0.5774 = 57,74 %
[-] means 180° degrees phase shift, then -0.8165 = 81,65 % phase-shifted 180° degrees.
Phase shifting "shifts" the audio wave acordingly to a 360° degrees axis. If the shift is 180°degrees wide, then what was positive will become negative and viceversa. by the properties of sound physic, when 2 waves have the same starting point, length (the duration of a cycle), and therefore the same frequency (Hz = cicles per second) but opposite values (Wave A in second 15 has 12 dB and Wave B in second 15 has -12 dB) they cancel each other out: this is called "waves cancellation" property.
When they have the values within the same "side" or "phase" (Wave A in second 15 has 12 dB and Wave B in second 15 has 6 dB) then they add their values up: 12 + 6 = 18 dB total -> The "Adding Effect" Property (not the real term, i can´t remember the technical one)
--->>
The 2-ch "Dolby Prologic II matrix-encoded" file:
Lt = [L x 1] + [C x 0.7071] + [SL x -0.8165] + [SR x -0.5774]
Rt = [R x 1] + [C x 0.7071] + [SL x 0.5774] + [SR x 0.8165]
* Mixing the LFE in Dolby Prologic II is not recommended by Dolby.
A decoding matrix then would try to invert the equation to recreate the 5 channels.
Dolby Digital: it´s the DVD standard for audio. Dolby Digital can be from 1-ch up to 5.1-ch audio files, with bitrates that vary from 112 up to 640 kbps depending on the number of channels. It´s know as AC3, also as A52.
DTS: the Digital Theater Systems compression technique. It´s a 6-channels (5.1) format. Uses bitrates of 1234kbps(for 44.1 kHz) or 768kbps or 1536kbps (for 48kHz). I don´t know if other bitrates are possible, but still is very limited in options.
The standard Dolby Digital is 5.1-ch at 448kbps, the standard DTS is 5.1-ch at 1536kbps (basically, 3 times more space needed that a Dolby audio track, that´s why I don´t personally like it.)
Others: AAC, OGG and MP2 are capable of multichannel encoding but as far as I know there aren´t hardware DVD-players capable of playing them (maybe for AAC but I don´t know the others). MP2 is low quality. AAC and OGG are great formats but are not used in DVDs. MP3 can be multichannel too (not a standard).
Software:
AC3Filter and ffdshow have customizable matrix features that allow u to create your own matrixes for decoding of AC3, DTS, AAC, OGG, and whatever other formats these Directshow filters can play. These are freeware.
BeSweet is a program capable also of customizable matrix encoding/decoding. Freeware. Great software for many tasks, but its AC3 encoder is not so good (the only downsize). Is not a filter.
Adobe Audition, Vegas Video, Maven3D Pro, Nero Soundtrax, Plogue Bidule are some of the products capable of creating multichannel encoding depending of your hardware some of them. These are paid software.
BUT TO ANSWER YOUR QUESTION IN AN EASY WAY:
the easiest, fastest way to create a 5.1-ch file is to set the the Speaker settings to 5.1, CMSS 3D to Active (or On), Surruond Mixer´s Recording Source to "What U Hear", and use the Creative Media Source® Player to record a 5.1-ch (by selecting "WAV. Multichannels" as Recording format). Remember to mute every input on the Surround Mixer BUT the Wave.
U´ll get a 5.1 96kHz(?) 24 bit mutichannel audio file in WAv format.
Open it with BeSweet and apply resampling (to 44.1 kHz and 16bits) and export it as 5.1 WAV.
Then Use OGG or AAC to recompress so u´ll get a smaller file than the WAV multichannel.
This a totally FREE-OF-CHARGE way for 6-ch upmixing.