Feature Request: Stereo Widening

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pksml
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Feature Request: Stereo Widening

Post by pksml »

Hello Chris.

I have been using Goldwave for several years!

I would really like to see a stereo widening effect in a future release. This is where you have a mono source and add/subtract frequency ranges to a second channel. This makes mono audio sound like it's in stereo. Would this be difficult to implement?

Here's a short article about widening:
http://en.wikipedia.org/wiki/3D_audio_e ... o_widening
DougDbug
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Re: Feature Request: Stereo Widening

Post by DougDbug »

This is where you have a mono source and add/subtract frequency ranges to a second channel. This makes mono audio sound like it's in stereo.
:wink: No... Your Wikipedia link is NOT about mono-to-stereo simulation. It involves creating L+R and L-R signals from a stereo source.

If you want to do a mono-to-stereo simulation, you can simply apply slightly different (complementary) EQ adjustments to each channel.

There are several ways to create L+R & L-R signals with GoldWave. The easiest way is with Effect -> Stereo -> Channel Mixer. (To get you started, the Cancel Vocals preset will put L-R in both channels.)

A few things to keep in mind... When you re-mix the "difference signal" with the original stereo, you can get a situation where the in-phase & out-of-phase signals affect the channel balance... You can get something like this:
L + (L-R) = 2L-R
R + (L-R) = L

You can "randomize" the phase relationships by adding some delay before re-mixing.
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Re: Feature Request: Stereo Widening

Post by GoldWave Inc. »

You can use the Equalizer effect on a single channel to simulate stereo. There is a similar post here.

Chris
DewDude420
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Re: Feature Request: Stereo Widening

Post by DewDude420 »

I would really like to see a stereo widening effect in a future release. This is where you have a mono source and add/subtract frequency ranges to a second channel. This makes mono audio sound like it's in stereo. Would this be difficult to implement?
honestly...this is actually really disgusting. I've done this in audition. It has a frequency panner which works in FFT, but it will allow you to specify how to pan frequencies. I will tell you the only time it worked with any success....on the older recordings from the 40's before magnetic tape was in full use...where things were recorded in one shot...like the old Spike Jones or Cab Calloway stuff (yeah...I dug pretty deep there didn't I...bet you didn't think I'd know who Cab was...I'm hep)...but it varied drastically with the recording. I've got sixteen presets of settings for one song and stuff like that. But as soon as i jumped to anything that was like a real studio recording...the results canged from a subtle realism to entirely fake. the actual shape of the panner was quite erratic as well...low frequencies stared panning left when they shot up to right for about 100 hz, down hard left for 75 hz, then spiked up to around 50% right before it started a very zig-zagged pattern till the high frequencies, where were almost non existent, this was followed by a widening of the stereo image with harmonic excitement and then some light studio reverb.

My original idea for this was based on what they did in the 60's to stereoify mono recordings....excessive EQ on each channel...but even most of that was horribly done...by the time I was done messing around with the old cab and spike jones recordings (becuase they seem to be done the old fashioned way....bunch of mics in a studio with a full band/orchestra going at once and everything going direct-to-disc, cab may have used tape...or something because there's no real noise with those tracks..while i had to do some additional cleaning up to whatever masters RCA has of jones) i had added a slight bit of reverb to the mix. i didn't really wind up with real stereo....but i basically simulated room acoustics to a degree....things sound like they have some seperation..but they don't at the time time. i was also working with a stereo-field method of panning rather than a simple amplitude....which will cause things to sound out of phase...which wound up being inadvertently by the reverb.....

i played around with it for two weeks before I finally abandoned it. I was even working on writing a paper on it and recommendations on the best way to implement it...i even called it FBI Stereo (Frequency-Band Interlace)...but I also try to engineer things to have a certain degree of realism...and when i couldn't nail down a solid way to do it (especially when working 50's "studio tracked" tracks) - my method's success heavily depended on the quality of the source and writing down enough details of just what exactly to listen for wound up being way too difficult...considering i can generally tell in a few seconds if a track is going to sound good or not.....

but as stated earlier, the easiest way to do this in goldwave is to run any of the EQ effects (or even spectrum filter) on one channel at a time. while this requires a lot of guesswork and no "instant-gratification"....too many people are spoiled by that these days and sometimes it's a larger challenge to put together in your head what you want the result to sound like then working on it in "chunks".

i'll dig up some of my mono-to-stereo examples and get some url's attached to this post later on.
Memory King
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Re: Feature Request: Stereo Widening

Post by Memory King »

Newbie here.

I've been experimenting quite a bit with trying to create "fake stereo", after hearing Mono recordings enhanced with Surround Winamp plug-ins. Some people really love broadcasting concerts in Mono for some reason, which makes a jarring change in the sound if I Shuffle all versions of songs from a band.

If you just want a half-decent sound in head-sets, stereo Reverb will probably be good enough, at least for a while.

My best result has come from using Equaliser on both channels, and applying Reverb afterword. I used ANWIDA DirectX plug-in recommended here on this forum, and was pretty happy with the result.

Anyhow, just wanted to say that the information here has been really helpful for making my bootleg archive sound relatively consistent.
parksinger
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Re: Feature Request: Stereo Widening

Post by parksinger »

Chris, thanks for the info on Mono to Stereo options.
The original question was about widening an (already) stereo signal, making a wider sound-space.

I've tried Flanger, but it introduces non-stereo artifacts... can you suggest a couple of other strategies or maybe minimalist Flanger settings to try, or maybe other filters or plug-ins to consider?

Thanks! (for a great product)
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Re: Feature Request: Stereo Widening

Post by GoldWave Inc. »

The Equalizer technique may work for stereo files as well, depending on how much of the audio is in the "center" channel. There are other techniques that involve copying one channel, applying the Equalizer or other filters and mixing it with the other channel, but that tends to involve some trial-and-error.

Also just inverting one channel can make a difference (use the "Inside out" preset in the Channel Mixer effect).

Chris
DougDbug
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Re: Feature Request: Stereo Widening

Post by DougDbug »

The original question was about widening an (already) stereo signal, making a wider sound-space.

I've tried Flanger, but it introduces non-stereo artifacts... can you suggest a couple of other strategies or maybe minimalist Flanger settings to try, or maybe other filters or plug-ins to consider?
First, you can get some creative "special effects", but most of this stuff is going to mess-up the sound of a song to some extent. :(

If you understand the algebra, you can accomplish most of what's described in the Wikipedia article with the Channel Mixer. (If it makes it easier, you can create L-R and R-L files and mix/blend these with the original.)

Try: Effect -> Stereo -> Channel Mixer with the Inside Out preset.

Or, try a something like this:
-- Left Channel --
Left volume = 75%
Right Volume = -25%

-- Right Channel --
Left Volume = -25%
Right Volume = 75%

Or, this isn't exactly "widening", but to add to the "stereo feeling" you can try mixing-in some delayed signal from the opposite channel:
- Create a copy of your file.
- Use the Exchange Channels preset in the Channel Mixer on the copy.
- Create a short delay by adding about 25 milliseconds (0.025 sec) of silence to the beginning of the copy-file.
- Mix the modified file into the original at about 30% volume.
- Volume Maximize to reduce the mixed volume and prevent clipping.

You can experiment with the delay settings and mix-levels to see if you get a pleasing result. Delays greater than about 50ms start to sound like an echo, and this probably isn't what you want. Re-mixing in a short delay also creates a comb filter (similar to phasing/flanging without the "movement"). A lower mix-in level will minimize the comb filter effect.

Notes:
- Experiment freely with the Channel Mixer, but it's generally best to keep the left & right "balanced"
- The minus sign is a phase inversion.
- Some operations will alter the volume level and you can Volume Maximize or Max/Match to keep a high level and also reduce the levels if necessary to prevent clipping (distortion).
- Mixing is done by mathematical addition. So for example if you mix a phase-inverted signal with itself you are effectively subtracting. (You can mix/blend the widened sound with the original, but try to understand the math because you can end-up doing things like completely eliminating one channel, etc.)
- The bass is generally in-phase and similar in both channels, so some of these effects can reduce bass. To compensate, you can use filters to create a separate bass file and re-mix in the bass after any "widening".
- Out of phase signals will cancel completely when played on a mono system. So, the Inside Out preset will act like a center-channel vocal remover on a mono system. And, some out-of-phase "center channel" information will be subtracted acoustically (in the air) when played in stereo.

:twisted: Have fun! :twisted:
pksml
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Re: Feature Request: Stereo Widening

Post by pksml »

Wow, dougbdug! That's some complicated stuff! Perusing back here at the GW forum, I see you practically live here! :lol:

I've figured out quite a bit of stuff in the past year since I opened this thread. I was quite the noob then!
Looks like reverb was the magic charm to my original question. I was just starting to work with vocals in processing our church's special music. After much trial and error, I've found that the vocals should just be in mono with a little reverb. The biggest enhancement was recording the instruments in stereo.

Goldwave is my down-and-dirty editing program before I hand everything over to Cubase to mix.
chris319
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Re: Feature Request: Stereo Widening

Post by chris319 »

I recorded an orchestra with a Sony ECM-MS957 mid-side mic. The mic performed quite nicely but I later decided that the stereo image could use a little more separation, so I "widened" the stereo image using the following settings in the Channel Mixer:

-- LEFT CHANNEL --
Left volume: 100%
Right Volume: -50%

-- RIGHT CHANNEL --
Left Volume: -50%
Right Volume: 100%

I then used Maximize Volume to bring back the levels. It did widen the image and I'm quite pleased with the result.

As you can see from the settings above, this takes 50% of the inverse of the right channel and mixes it into the left channel, cancelling half of whatever right channel audio is present in the left channel and vice versa.

I had also tried taking 100% of the inverse of the channels instead of 50% and the result was not so pleasing. This could be due to overlap of audio information between the two channels.
Tristan
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Re: Feature Request: Stereo Widening

Post by Tristan »

Simple stereoizing trick, using Audacity:

Import identical mono files into left and right channels.
Pan hard left for left channel, hard right for right channel.
Shift either left or right track up to 30 milliseconds.
Save as stereo file.
I don't want to read the manual either, but it isn't my problem, is it?
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Re: Feature Request: Stereo Widening

Post by GoldWave Inc. »

To do the same thing in GoldWave, you'd save the mono file as stereo, then use the Edit | Channel menu to select a channel and use Edit | Insert Silence to insert 0.03 seconds of silence to shift it.

Chris
Tristan
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Re: Feature Request: Stereo Widening

Post by Tristan »

I guess you use the Channel Mixer to do the final channel separation adjustments.
I don't want to read the manual either, but it isn't my problem, is it?
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