Anyone Here into Mono-to-Stereo Conversion?

[Anderton]

I'm asking because given that I use guitars and vintage synths, sometimes the outputs are mono. But I'm also finding techniques that are useful when you have several mono background vocal parts. Some conversion techniques are based on EQ, some on delay (but without causing notictable phase issues when collapsed to mono).

 

If there's interest, I'll present some of my findings.

[KuruPrionz]

I often take a mono track, copy and paste one or more identical tracks and use them to create more open, spacious sounds. 

The one I do most frequently remains mono - dupe the bass track, add a high pass filter around 320hz and add a "tube guitar amplifier" plugin with distortion. 

That track gets turned down quite a bit, it makes the bass part clear in the mix without clutter, even if the listener is hearing it on their cell phone with a tiny speaker. 

 

I do like stereo background vocals and guitars as well, sometimes those get just a tiny bit of pitch shift and or modulation to create a more 3d atmosphere. 

I've gotten extreme with effects more than once but I usually find the results are not so pretty. A light touch sounds better to me. 

[Mr -G-]

30 minutes ago, Anderton said:

If there's interest, I'll present some of my findings.

Please do! I have also been interested in "pseudo-stereo" processing.

[Stokely]

If I have multiple mono parts I generally just pan them apart to whatever degree and that's that   If it's me doing the recording, I will often do several different takes if I want "stereo" as the difference in the parts can create interest.  Definitely with guitars this is something I like do, and besides the new take I will usually change the amp sim, pickup, position etc to give a bit more difference which widens it more.  I have played around with using a simple all-wet stereo delay or shifting the sample over on a duplicated track to try to make a stereo sound but I've never been too happy with the results.  Again, more with guitars than anything else.

For vocals to give a bit of width I sometimes use the common technique of a short stereo delay with different time on each side.  How short depends on tempo but for example you might have 50ms on one side and 80ms on the other, or something a bit wider if you like.    Then dial both the wet/dry mix and times up or down to taste.   I like it best when it's shorter/drier than a distinct slapback sound.  This is one of the few times I use the boring ol "stereo delay" in Logic    Tape Delay works too.

[Anderton]

Most of the time I'm not going for super-wide stereo, but with guitar, its "mononess" stands out in a sea of stereo drums, keyboards, and two or three vocal tracks. Basically, I have two main techniques: Separation via EQ, or separation via delay.

 

When you listen to a guitarist, it's not mono. But, the recording process constrains you to that unless you use stereo miking on acoustic guitars (and then you have to deal with phase and other issues). To give a guitar sound that fills the stereo space without sounding like "wow, listen to that artificial-sounding stereo guitar," I often use EQ.

 

One of my favorite techniques is sending the guitar to two buses, and inserting a multiband dynamics processor in one of the buses. All the ratios are set 1:1 so there's no dynamics processing. Basically, what you then have is a 4 to 6-band graphic EQ. Then I move the crossover frequencies so there's equal energy in the various bands. Once one of the EQs is tuned, I copy it to the other bus and pan them oppositely. Finally, I'll mute the high, and mid bands on one EQ, and the low mid and high mid on the other. Bass often stays in both to stay centered. This spreads the different frequencies out in stereo. You can also bring up the original track feeding the buses for more emphasis in the center. Unlike delay-based techniques, this collapses perfectly to mono. 

 

If the following phase meter was showing a mono track, it would be a straight line up and down. Using the filter-based mono-to-stereo conversion gives a wider stereo spread:

 

 

With delay, I usually choose prime numbers for the two delays. The key is the dry/wet setting. Less dry and more wet means the sound won't collapse well to mono, but more dry and less wet doesn't give a big stereo effect so you have to trade off. If I don't go much above 20-30% dry, the sound still seems okay when played back in mono. The images below are (left tor right) mono, with 20% wet, and with 30% wet.

 

[techristian]

Waaay waaaaay back I used to like recording tv  themes music, such as "The Streets of San Francisco" , "Hawaii Five O" etc. We only had MONO sound on tv back then. I mostly used EQ to create a stereo image, but I also did a few novel things like using RESONANT FREQUENCIES and sympathetic vibration. I remember , one time, placing a microphone very close to my FLOOR TOM while the mono sound was playing on a speaker close, and recording the original VIA direct hookup to one side and the Microphone side to the other. It produced some interesting results.

 

So lets take this to 2023.

Now take a speaker, playing the original synth sound,rich in harmonics,  and take a carefully tuned acoustic guitar NEARBY and CLOSE MIC it, perhaps even have the microphone inside and record it while simultaneously recording the dry signal to the other channel, you might get some surprises!

 

I forgot to mention the final step.

Now take your favorite WAV SOFTWARE, mine is Cool Edit and INVERT the source wav. then add it to the RESONANT side. The source will be subtracted leaving PURE resonance for the resonant wave. Copy this to one side and turn the volume up if necessary, and copy the dry signal to the other side... PSEUDO STEREO

 

Dan

[Stokely]

What's the old adage...when everything is stereo, nothing is?    Or maybe that's not an old one, but I heard it somewhere.

I've been in the same boat with a mono guitar track.  It can make things quite unbalanced and unless you are going for the Beatles or Van Halen's first album, that's probably not what you want.   If it's a song with only guitar and vocals, that's generally the time I want a 2nd one for balance.   If there are keys, I'll often take a keys part and pan it opposite, perhaps not mono nor all the way, just to offset one guitar.

Those super cool stereo keyboard patches sound great on their own but you add a few of them together and it can turn into mud quickly.  I find simpler parts, even mono, can add up to a bigger sound (The Cars Drive is an example).

Interesting subject for sure!

[Anderton]

I generally choose mono guitar with a stereo image over two guitars to create right and left. Not always, of course

[KuruPrionz]

36 minutes ago, Anderton said:

I generally choose mono guitar with a stereo image over two guitars to create right and left. Not always, of course

Agreed. If there is more than one guitar then they will usually be doing different things. I do have a couple of guitars tuned to Nashville tuning, sometimes playing the same thing as the first guitar with a Nashville tuned guitar can be the "stereo" if you pan them left and right. I have a 12 string too but you can't get that same sound. 

[Bill Heins]

Mono 6 string guitar played three times with three different pickup settings panned L, R, and C. Center channel is more for a simplified version of the rhythm at a lower volume. All three tracks are sent to a stereo Guitar Buss for compression, delay, verb, etc. 12 string guitar I record stereo each pickup setup at L67, R67, C. 12 string tracks go to a 12 String Stereo Buss for the same reasons as the 6 string. Bass Guitar is mono and centered. Drums...bass, snare, toms, and hihat are mono..crash cymbals, room and OH mics are stereo. Kick centered, Snare slightly right, etc. to place the dums in a listener position. Drums go to a stereo Drum Buss that has 2 FX Sends to seperate Compression(crushed!) and Reverb Busses.

 

Bill