making stereo from mono?

[Svart]

So I'm looking for something that could emulate "stereo" from a mono source.. perhaps a small phase shifting delay of some kind.. anyone have an idea handy before i go and bang my head against the wall for a while?


What would be a good start? some type of multiple buffer setup? i'm not looking for mega delay, just enough to hear a difference.
:guinness:

 

[fazeka]

I dunno about phase, but I do know that Capitol did it with EQing the channels back in the '60s. Can you say "Duo-phonic"?

 

[rodabod]

I have experimented with this myself.

My own method was to have the mono source split and to operate on a left and right channel seperately.

I then applied delay (very short) to one side and applied eq to make each side sound slightly different. Worked nicely.

Depends on what sort of ambience you are mixing in.

 

[Gus]

I believe I read in an old audio mag that a crossover network would be used to send the highs to one side and the lows to the other for a stereo effect. I have not tested this.

 

[pucho812]

well in order for it to be stereo the one channel has to sound different from one side to the other. Most Modern FX units have a mono to stereo setting in them where they usually add EQ, delay not much and some verb. You can get away with panning one signal hard left and then delaying it about 50MS and panned opposite. Can get that kind of delay time out of a stomp box. It might be cheaper just to buy an old DOD or digitec rackmout.

 

[rodabod]

Forgot to mention, the eq I applied to each side was the inverse of the other.

For instance, if I had a 2 dB boost at 1 KHz on the left channel, then I cut by 2 dB at 1 KHz on the right channel.

This helped maintain the original content.

 

[daArry]

Heres a schemo of the orban stereo synth doodaathingy:

mebbe some inspi there :thumb:

 

[TomWaterman]

Hey svart,

if you don't want to build a specific box to do this the quickest way that comes to mind is using a mono in / stereo out reverb. Just set the verb to be very small and I doubt you'd need to go wild with any pre-delay...to make it wider when your done you could either:

Use some form of stereo widening plug like Waves S1 etc or do the pitch shift trick to one side or both (one up, one down).

If you print the track to a DAW you can slide the left channel back approx 10-20 samples and the right forward by the same amount, central timing info is kind of preserved but it gets wider...

On a console:

Split the mono channel to two channels...pan one left, one right and add mono chorus or pitch effect to one side...won't be as natural as the verb tho.

What is it that your widening - guitars?

You can also use subtle-comb filtering of the mono source which feeds two hard panned channels, one phase inverted....the original unfiltered sound stays panned centre.

HTH
Tom

 

[Svart]

Thanks everyone!

DaArry: that's similar to one of the circuits i was thinking of! I might just have to give it a go!

Tom Waterman: I'm working with guitars right now. I've been experimenting with splitting the mono signal and delaying one of the channels. It works very well indeed but i was actually thinking of making a box with multiple channels of simple delay(lag?) just for this purpose. I came to this conclusion when fiddling with the delay boxes i use now, which are all digital, and of course make the audio sound digitized on the delayed channel. I was hoping to come up with a simple analog solution to delay the signal a few ms but doing some math seems like it might be a little harder than i had thought.

Rodabod: I haven't tried the EQ approach, but i will!

Initially I thought about just stuffing a board full of buffer-type circuits and just letting the signal get slowed down through the chain.. I'm not looking for a repeating delay, just a lag really.

:thumb:

keep the ideas coming and i'll start to work on something here!

 

[jrmintz]

Hey Svart,

I don't know if this applies to your situation at all, but something I often do to generate a doubled guitar part is to find repeated sections and put the first verse with the second verse and vice versa. If there was a consistent enough performance and the tune is broken up in even sections sometimes I can create a real double all the way through.

:thumb:

 

[12afael]

I`m using a plug in from "waves" doubler is the name. it delay ,change the pitch (like a lfo on the delay),and eq it work great .
the main failure of the only delay metod is that you can ear what side is first cause you ear it more loud (you ear it on that way).

 

[gyraf]

Try looking up the TDA3810 stereo enhancer IC - that is a stereo-faker on-a-chip..

Jakob E.

 

[CJ]

If you have the stuff to try something weird you might try playing the mono signal through a set of dis similar speakers, then recording it with a couple or more mics in stereo.
On a scale of 1 to 10, how lame does that sound?
Go ahead. I can take it. I'm your human punching bag. Have at it. Just don't use negative numbers or I might decide to run a class 6 rapid this weekend in the dark and facing backwards while on peyote. Oh yeah, no life jacket , no helmet, an ice picked kayak, and no life insurance.

:?

 

[bcarso]

You know where to get peyote?

 

[Sammas]

I've had good results by just stemming the mono sound to both left and right then applying different compressors or eq's on each side...

 

[Svart]

I'm interested in that TDA3810 IC but it's now discontinued and the only website that will sell to a private individual wants 40$ USD!


:shock:

EDIT: i found a place with some stock for much cheaper.. going to get a few..

 

[NewYorkDave]

The complete manuals for the Orban 245 and 275A stereo synthesizers are available here.

They used a clever comb filtering arrangement that gives a good effect and the output sums back to mono pretty well also.

 

[TomWaterman]

That graphic trick is the crude comb-filtering thing - I guess similar in essence to the Orban one....

Would an all-pass filter network to create phase lag work in the analogue domain?

Say create a box that splits a mono signal 3-ways...one panned centre (routed to both L+R) and then one copy left, another right with a series all-pass filter set to different phase delays on each side?

Would that not create a natural comb-filter effect based upon the (de)constructive interference of the out-of-phase signals?

-Tom

 

[Svart]

why go stereo?

It's all about the stinky stinky and the ca-ca dookie.

 

[bcarso]

Seems to me Prologic does something like this for getting two rear channels out of a single signal.