need to sum stereo to mono at the end of signal chain - options?

Junta

Member
Messages
1,731
Hi there

I have done my homework on this... Well kind of... Once you get into the phasing issues, that's where you will lose me...

I have found links to a pedal which does sum to mono here: https://goodwoodaudio.com/product/theinterfacer/

Looks pretty good on paper (and in the demo video on the manufacturer's website):


I know that NeuNaber Immerse also does the job of summing to mono if one of the stereo output jacks is unplugged (the manual very clearly explains this).

Except, I am super happy with the two reverbs I recently got;

- Catalinbread Talisman: Superb pedal - cannot praise this enough. For mono recording, absolutely! I am going to move the Talisman to my ìn-front-of-amp board, so it will not interfere with the stereo routing at any point. With a pedal that sums to mono, I could move the Tlisman temporarily to the very end of the chain if I must absolutely have it after my loop board pedals.

- Flint (Plate): Not comparable to the Talisman in my view, but still very good. For stereo recording/noodling (to self).



As you can see, when it comes to recording/noodling in mono, I am in a bit of a bind here. I am running the Quantum, the Tripple delay, the SuperPulsar and the Flint in Stereo. If I change routing with a few quick `ìnterventions`, I could run the moog flanger or the phaser in stereo too (but not both at the same time...)

I need to be able to go between mono and stereo without changing the entire board routing - like with flicking the mono/stereo switch in the Goodwood Interfacer pedal, or by unplugging one jack with the NeuNaber Immerse.

Are there holes in my theory here (I bet there are... Phase issues, right?) Any other, cheaper or better options out there?

Cheers!
 
Last edited:

Junta

Member
Messages
1,731
Thanks Triski. A cheaper and probably just as good option.

I wish there were a reverb pedal which could sum to stereo that did plate as good as Flint (if not as good as the Talisman)... A tremolo pedal which could sum to mono? I guess not.
 

stevel

Member
Messages
14,659
Just so you know, Phasing is caused when you have two (or more) signals that are identical, but not "lined up" perfectly.

One way to get them out of line is to delay one of them slightly.

Another way is to electrically invert the polarity.

Both have the same basic result - when the crests and troughs of two waveforms line up you get "constructive interference" and the amplitude adds together. Since the waves are "identical" in our example here, it doubles the amplitude (which results in a 3db increase).

If the crests and troughs don't line up, you get "destructive interference". If a crest lines up with a trough and vice versa, and again the waves are identical, you get 100% cancellation.

If you electrically invert (flip) a waveform, or delay it enough so the 2nd wave is 180 degrees out of phase with the first, you get complete cancellation.

If however the phase is only partially shifted, the result is a change in shape of the waveform - this means the tone of the resulting sound can change.

Since two signals from the same source summed to mono usually means "identical" signals, phasing issues generally produce destructive interference in a way that results in a "thin" or "hollow" sound - you know, if you hear a phaser pedal, it's not far off because it's basically doing the same thing.

Audio engineers monitor in mono to check for phase issues when they have two mics set up on the same sound source.

In your case, if you have one source (your guitar pickup) that is split into two signals, if either of those signals is electronically altered or delayed down the line some where (I'm not talking about an echo delay, I just mean that the signal is a percentage of a millisecond off as can happen when digital devices pass information) when you recombine them you could get some phasing issues.

The only way to really tell is to try it with your setup.

If you have an old A/B/Y sitting around you could try it with that - take your two signals into A and B and then "Y" them out the single jack and on to your amp.

Maybe what you really need is a looper/switcher with stereo capabilities. I'm curious how you're recording though, and why you're recording in mono - or did I misunderstand that?
 

Junta

Member
Messages
1,731
Just so you know, Phasing is caused when you have two (or more) signals that are identical, but not "lined up" perfectly.

One way to get them out of line is to delay one of them slightly.

Another way is to electrically invert the polarity.

Both have the same basic result - when the crests and troughs of two waveforms line up you get "constructive interference" and the amplitude adds together. Since the waves are "identical" in our example here, it doubles the amplitude (which results in a 3db increase).

If the crests and troughs don't line up, you get "destructive interference". If a crest lines up with a trough and vice versa, and again the waves are identical, you get 100% cancellation.

If you electrically invert (flip) a waveform, or delay it enough so the 2nd wave is 180 degrees out of phase with the first, you get complete cancellation.

If however the phase is only partially shifted, the result is a change in shape of the waveform - this means the tone of the resulting sound can change.

Since two signals from the same source summed to mono usually means "identical" signals, phasing issues generally produce destructive interference in a way that results in a "thin" or "hollow" sound - you know, if you hear a phaser pedal, it's not far off because it's basically doing the same thing.

Audio engineers monitor in mono to check for phase issues when they have two mics set up on the same sound source.

In your case, if you have one source (your guitar pickup) that is split into two signals, if either of those signals is electronically altered or delayed down the line some where (I'm not talking about an echo delay, I just mean that the signal is a percentage of a millisecond off as can happen when digital devices pass information) when you recombine them you could get some phasing issues.

The only way to really tell is to try it with your setup.

If you have an old A/B/Y sitting around you could try it with that - take your two signals into A and B and then "Y" them out the single jack and on to your amp.

Maybe what you really need is a looper/switcher with stereo capabilities. I'm curious how you're recording though, and why you're recording in mono - or did I misunderstand that?
Thanks so much Steve! I need to digest your reply, and do some additional reading. I knew about phase issues a bit because I need to deal with them with micing; it is the polarity reversing bit that I need to read on I guess...

I do have a Radial BigShot ABY, so I am going to try that for sure. A looper which does what I am looking for would solve the issue, but I really have no room for one on my boards. In my `in-fron-of-amp`board I already use the Radial BigShot EFX to `protect my fuzz pedals `from the devastating (!) buffer of my Moog MF-101 low pass filter, and I would rather have more fuzz on my pedal board :)

I record mono when I double track dirty parts to get them wide and big. Not the best when it comes to double tracking, so especially with clean parts, I tend to prefer single take stereo...

Also... I `pretend` that I can play the bass guitar parts when I record, so that requires mono because I go through the same board with bass and guitar.

Thanks again, cheers!
 

Root5150

In Denial
Messages
290
https://goodwoodaudio.com/product/output/

this is $60 cheaper than the interfacer, and will do the summing for your rig
^^^This^^^
I've had the Output for a couple months now and it works great. Haven't experienced any phasing issues to this point and the build quality is tops. Fwiw, I'm running a Möbius-H9-Timeline-BigSky at the end of my chain and summing to mono with the Output when stereo isn't an option.
 

Junta

Member
Messages
1,731
excellent vote of confidence for the pedal - thank you Root5150. Yeah, I think this looks like the GoodWood Audio Output is my best bet.
 

augur

Member
Messages
1,315
Did you try the Empress Reverb?
It may replace both of your reverbs, sum to mono with additionnal and useful output feature!
 

MartinCliffe

Member
Messages
1,968
I also use the Goodwood Output, really great product, simple but works perfectly and doesn't colour the tone at all.
 
Messages
2,019
I have been using the pedal that you're mentioning in your OP: the Immerse. I am (also) running the:
Mobius => TCE Triple Delay => Immerse
stereo thing with great success. It's only a matter of adding another cable out of the Immerse. Or not. Which, BTW, does an out-freaking-standing good plate reverb, since you ask.

I would strongly suggest asking Santa for one...
 

Junta

Member
Messages
1,731
Did you try the Empress Reverb?
It may replace both of your reverbs, sum to mono with additionnal and useful output feature!
I could not find anything that speaks to summing stereo to mono in the manual. Does empress explain this anywhere on its website?

Thank you
 

augur

Member
Messages
1,315
I could not find anything that speaks to summing stereo to mono in the manual.
I own it and been doing what youre talking about for some months.
Before I used to do the same with a Stereo Wet.
Output volume can be useful because you lose around 2db when summing to mono.
 

Root5150

In Denial
Messages
290
I own it and been doing what youre talking about for some months.
Before I used to do the same with a Stereo Wet.
Output volume can be useful because you lose around 2db when summing to mono.
Hmmm... wouldn't the 2db volume drop be indicative of some sort of phase canceling going on? I'm only asking because I still don't have a good grasp of this concept and I don't experience the volume drop with the Output.
 




Trending Topics

Top