| thanks for your well detailed response richard. perhaps i'll sign on to
that list for a bit.
in the theater space i just left, i was playing back a simple stereo file.
the speakers unfortunately were not well placed for much of the audience
-too high, too far apart, and too far forward (a few rows of the audience
were even behind the speakers!). among the results: that whole in the
middle i mentioned. not just for sounds panning, but all the time. now of
course the speakers could have both been tilted towards the center a bit
but that would have ruined the imaging for a portion of the audience
further back. next time i expect to have more control over placement and
that should help.
for those jumping on this thread let me repeat that i am not referring to
5.1 as it is usually configured for surround sound. this is about taking a
true quad mix and adding an additional speaker between the two in the front
without altering the quad image.
tolve
>I have some general comments around this;
>
>there is a surround sound discussion list (described on Dave Malham's
>Ambisonics website: http://www.york.ac.uk/inst/mustech/3d_audio/ambison.htm
>
>they spend most of their time discussing phantom sources, pinnae reflections,
>speaker placments and the DVD/DTS fracas, but some useful information emerges
>from time to time. Dave Malham also has Csound examples of ambisonic encoding
>of sounds with rotational control. His website covers the basic maths of it,
>and has pointers to digest lists for surround sound and Ambisonics.
>
>Ambrose Field, a composer at York, has recently completed an electro-acoustic
>piece using Ambisonics, and, I belive, now has a commision for a new piece,
>from ICMA. Ambisonics is a much more sophisticated sorround encoding and
>diffusion system than raw 5.1, and may be more what you are looking for,
>especially if you want to rotate sounds, or soundfields, periphonically.
>
>With regard to multi-channel files, both WAVE and AIFF can in principle be
>extenede to any number of channels (Csound will write a quad WAVE file, for
>example, if asked). Soundcards are now appearing which can play such files
>(Sonorus Studi/o, Creamware Tdat-16, and their imminent PULSAR card), so you
>will not be obliged to manage separate mono files (unless that suits your way
>of working, of course!).
>
>A 8-channel opcode was posted to this group some while back, and I recall it
>is one John Fitch's list of Things To Do, to addd this to the canonical
>sources in some generalized form. I'm not so sure about quad input though.
>
>A precursor to what you describe is the SPACE unit generator which F.R. Moore
>provide in his program CMusic (PC version called pcmusic).
>
>5.1 originated as a Cinema surround format, and the centre channel is
>typically used for dialogue (localized), rather than for music. I don't think
>in itself it would do much to remove 'hole-in-the-middle' effects - plain
>stereo constant-power panning can do that already.
>
>I am also working on multi-channel support in CDP - do feel freee to email me
>privately if you want more info on that.
>
>
>Richard Dobson
>
>tolve wrote:
>>
>> Warning: dull laborious, though real world problem ahead!
>>
>> let's begin with the goal:
>> start with a discrete quad mix consisting of 4 individual (mono)
>>soundfiles (AIFF's) and enhance it by automatically creating a fifth mono
>>soundfile.
>>
>> definition:
>> 5.1 usually refers to a speaker set-up frequently used for stereo
>>surround sound (not the topic of this post). 3 speakers are positioned in
>>front, 2 in the rear, and the ".1" refers to a subwoofer which handles
>>the low low frequencies. for purposes here, let's forget the subwoofer as
>>an outboard crossover will handle that nicely. what i refer to as the
>>enhanced part is the extra speaker located at middle front -quite useful
>>in large venues to avoid the "hole in the middle" sound effect and for
>>more precise perception of position of sounds. ok if you prefer to call
>>this pentaud or something. just want to make it clear that we're not
>>adding another dimension.
>>
>> challenge:
>> surprisingly enough, in this case to spotlight csound's superior
>>efficiency against commercial mixing aps including USD20000+ digidesign
>>protools system.
>>
>> desired method:
>> pull 4 discrete tracks (mono soundfiles) into csound individually using
>>diskin. these would then be used to generate automatically the fifth
>>(center) track (mono soundfile).
>>
>> Important: the positioning of the sounds and the manner in which they
>>pan should not be altered by the addition of this extra track (speakers).
>>the result would be, in the case of 5.1, five separate aiff files.
>>
>> to further clarify: the levels of the four discrete tracks would be
>>adjusted accordingly and the new fifth file would be created in such a
>>way as to maintain all positioning of sounds in the quad image as they
>>were in the original quad mix.
>>
>> Incidentally, if anyone is feeling additionally ambitious, 7.1 adds to
>>the above additional enhancements: 2 speakers, one on each side midway
>>between the front and rear speakers (middle left and middle right). for
>>7.1, the result would be seven separate aiff files, again positioning of
>>the sounds and the way in which they travel should be the same as in the
>>original quad mix. and in a large hall, keep adding speakers till your
>>budget bursts!
>>
>> ok. 5th file generating orc & sco anyone?
>>
>> would also welcome, in a separate post, a mathematical response which i
>>will subsequently hope to one day understand.
>>
>> and in case someone thinks this is best addressed with a new opcode,
>>don't blame me (smile).
>>
>> tolve
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