Hi: I have a WAV mono file (only one channel) and want to create a stereo file one of whose channels is a copy of the mono file and the other channel has no signal. That is, when playing the output file I will hear the original mono file in say the left channel speaker but no sound at all from the right speaker. I thought I could do this with sox but after skimming through the manual I'm not so sure now. Can sox do this? If not what program can do the job?

i thought it would have to use synth, but it's simpler
http://sox.10957.n7.nabble.com/Creat...el-td4663.html
so just something like
sox mono.wav stereo.wav remix 1 0

PS sox can do anything

1 members found this post helpful.

How stupid I am! I quite missed the remix option. So I could equally well take a stereo file and erase the right channel with

sox stereo.wav left.wav remix 1 0

Wonderful!

Greetings
Additionally if you don't mind a little work and having some fun doing it, you can create your own stereo imaging with a DAW. There's a bit of a learning curve with say, Ardour, but it has matured nicely and is well worth any effort you put into it if you do this sort of thing regularly. With EQs, Compression, and especially Delays it is possible to create an image from a mono file that has an apparent Center, Left, and Right. Those 3 LDAPs alone open up a whole world of audio manipulation and creativity.

For perspective I took a 20 year old Mono Cassette recording that was also flawed to begin with because it was taken of a PA mixing board, which is not what was heard "in the air" but rather what was lacking "in the air". With a DAW I created a stereo file with proper balance of instruments and very nearly what it sounded like to be there, with just a bit better high end resolution and clarity.

While there are tradeoffs between Analog and Digital, Digital puts the power that only 10s of 1000s of dollars would buy in analog, to anyone willing to download (for free) and learn.

i completely agree
ardour is just amazing, thanks to its maker
but sox is also as good, despite not looking like it is

as for 10k$
http://sound.westhost.com/project09.htm for crossover/mixing
and
http://users.ece.gatech.edu/mleach/lowtim/
as an amp
or http://www.synaesthesia.ca/PGP.html if you want the most precise amp known to human kind (it's insanity in its purest form)

but yea, digital can get there thanks to the Nyquist frequency theory
all of the popular open source filters/resamplers are good now
a little comparison http://src.infinitewave.ca/ (sox can output those graphs)

i like audio

And of course, I think Audacity would have done this quite easily too.

Overall I like your style.....however when it comes to amps..well...
OK I followed the link and it did look pretty amazing until I saw the gobs of negative feedback, clipping control, and all the rest that goes into making a solid state amplifier not be a switch and attempt to be a linear amplifier. They look positively awesome on meters and generally SOUND awful in human ears and brains at the low end or kind of decent on the high end.

BUT If you want a mind-boggling EARGASM !

---!!!!!T H I S!!!!!---

is your personal pornstar.


However I have to admit that to qualify for insanity it might be something like this -

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yes
despite the advances in manufacturing transistors, they are still not perfectly linear
so it is impossible to get this low distortion without negative feedback, and they did the feedback in stages
there is more on diyaudio about the amp, it is there where it started

i still have not found any amp with under 1 ppm distortion on 100W over 10kHz

it's not a switch, it is a 2x current valve (or voltage limiter in case of FET's)
in case of AB design

to be honest, i never was that hyped about tubes, thou
i do know a guy that made a 1kW output tube amp it was hilarious

also an ex colleague of mine was into tubes
he made a small one tube preamp, then just feed it to a transistor amp
we had good tubes back then, some ukrainian or russian stock from before the last war
i did however find that tubes have interesting distortions when over-driven


if someone is interested in transistor amps, i recommend Audio power amplifier design book by Douglas Self
one of the rare books i actually read from start to finish

edit: forgot to say, the amp looks like much care has been put into it
my Leach is just screwed to a plank, a danger to children and small animals

I think it is far less important how much distortion is created (beyond a point) and far more important what KIND of distortion occurs. Negative feedback no matter how well distributed introduces phase smearing. No amount of improvements in solid state manufacturing, even of mosfets, can limit the inherent speed (read "very high frequencies" including very high order distortion products) slew rate induced problems and Transient Modulation Distortion. In addition, printed circuit boards have their own noise and interaction problems (mostly capacitave).

There is also a the physics problem that every additional stage creates phase shift so having to add control circuits adds greatly to this issue and also has a negative effect on damping factor. All of these problems create a sterile sound.

There is no way to describe this in words that will display the weight of these issues. All I can say is that if you ever get the chance to hear an audiophile vacuum tube system (even better with an audiophile solid state amp to A/B) do yourself a favor and don't turn it down. Hear it for yourself. Comparing solid state to tubes is akin to looking at a picture of the Grand Canyon vs/ standing on the ridge.

damn you for knowing these things

i'l repeat a couple things from you here
i agree, humans are more sensitive to phase then magnitude (loudness)

phase drifting with frequency depends on the speed of whatever transconductor is used and the amount of feedback, for designs with feedback
for pure, feedback-less, class A amp's the frequency induced distortion comes close to the transconductors maximum frequency
for older transistors it was fairly low, especially for cheaper ones (still well above 20kHz)
while more modern transistors easily go over 100MHz (2SC3503, as a random pick from the PGP amp, goes to 150MHz)
tubes ofc go much higher, also depending on their quality

so... phase drift
yes, negative feedback does cause it
it goes up linearly with the magnitude of negative feedback and the signal delay between the point where it come from and where it is sent back
so it matters more on the design

this is where you got me thinking about PGP amp's feedback network design
it has local loops for each stage, that would have lower impact due to shorter signal length
but it also has a global loop... makes me think how much feedback
well it has a 7.56k resistor for that, but i'm too lazy to calculate the current difference from that and normal current input at that point

mr Leach, however, did measure it for hes amp here
-8.8° at 20khz
i think that's not so bad
in some 5 years or so i won't be able to hear it anyway

intermodulation distortion they have measured for the PGP was under 120dB
in transient form of it would also show up in measurements, especially the clipping ones


all in all i still put more importance on the speakers and the room
considering the amount of distorting of phase vs frequency and magnitude vs frequency coming from moving a cone and a coil (and box design)
i doubt any modern amplifier could match

absolute phase shift does not matter in most cases (the input-output delay one)
it's even greater when a DSP is in the mix

in short, electroacustics is never that simple
and i may be wrong on some things said here, more or less

as for the eternal solid state vs tube argument
i find it a matter of taste
after all it is art playing from that speakers