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stereo pedalboard -- easy conversion to mono?

rumbletone

Silver Supporting Member
Messages
7,392
You know, I've thought about several times, but keep thinking about how it will be received on the market and I don't know that there would be much demand for it as a lot of guys don't run stereo and might find this sort of gear too technical to use.

I'm am super stoked that you guys are into it, and believe me that I would love to make a production buffer/interface to do this, I'm just afraid I'd be sitting on them forever. Maybe I'm crazy!

Thanks again fellas!
Unless it deals with phasing issues I'm not sure it would be that useful. There's a reason most people don't just sum stereo to mono . . .
 

thiscalltoarms

more gadgets than Batman.
Platinum Supporting Member
Messages
8,155
Ok, so we may have to wait and just see how it works, but are we thinking: 2 inputs > stereo outputs; remove right input > mono signal from both R & L output?
I didn't ask that when I asked for details. I made sure it does two stereo ins, when you unplug one of the outputs it sums both stereo inputs to a mono output. So say you have it behind a Ping pong delay. The Ping pong R / L plug into the T1m box, and if you plug two cables into the other side it continues in stereo, but if you only plug one output cable from the T1M box it sums the ping/pong R/L to the single plugged in output cable.
 

thiscalltoarms

more gadgets than Batman.
Platinum Supporting Member
Messages
8,155
Unless it deals with phasing issues I'm not sure it would be that useful. There's a reason most people don't just sum stereo to mono . . .
How many pedals out there have out of phase stereo outputs? I know the Strymon's outputs are correctly in phase with each other.
 

baggas

Member
Messages
473
Ok, so we may have to wait and just see how it works, but are we thinking: 2 inputs > stereo outputs; remove right input > mono signal from both R & L output?
That doesn't make sense to me.
What we want is for the two stereo inputs to be plugged in at all times.

If plugs are plugged into both outputs then it will output in stereo. If one of the outputs (eg Right) is not plugged in then the two stereo inputs will be summed to mono.
Removing inputs the way you say would make it impossible to get the summing we are chasing.

Regarding the phasing, I currently have two amps plugged into the same power strip connected to the left and right outputs of my Strymon Bigsky, with no sound issues, hum etc. I am assuming that the same should be the case with these inputs being forwarded through the summing box as well.

EDIT : Actually I just saw thiscalltoarms comment above which describes it the same way I understand it. I have a ping-pong delay ready to go on my board in order to test this principle once I receive the T1M box.
 

rumbletone

Silver Supporting Member
Messages
7,392
How many pedals out there have out of phase stereo outputs? I know the Strymon's outputs are correctly in phase with each other.
To be clear - I'm not talking about polarity being flipped - I'm talking about phase issues that result when summing two signals that are similar (i.e., originate from the same source) but that have either been mic'd/generated in stereo but in a manner that is not 'mono compatible' or been processed in stereo using algorithms that are not mono compatible. Some stereo signals will sum to mono just fine (for example, a mono signal that's been processed to a simple ping pong delay), but many will not - especially any that use phasing tricks to create a 'faux stereo' image. So if you know that all your stereo processing is mono summable - then great go ahead and sum to mono using a simple 2>1 mixer. But if not, it's more complicated to sum them without risking phase cancellation, comb filtering, or other undesirable artifacts.
 

rumbletone

Silver Supporting Member
Messages
7,392
.

Regarding the phasing, I currently have two amps plugged into the same power strip connected to the left and right outputs of my Strymon Bigsky, with no sound issues, hum etc. I am assuming that the same should be the case with these inputs being forwarded through the summing box as well.

EDIT : Actually I just saw thiscalltoarms comment above which describes it the same way I understand it. I have a ping-pong delay ready to go on my board in order to test this principle once I receive the T1M box.
Plugging into two different amps shouldn't cause such phasing issues (unless you try to sum the mic'd signals back to mono, though once they are mic'd that's a whole different set of concerns...though of course you should ensure that they do not have opposite polarity - or if they do then flip the polarity on one of them).

A simple ping pong delay should be just fine - since there aren't delays from left and right happening at the same time to cause issues.
 

zwolf

Member
Messages
404
To be clear - I'm not talking about polarity being flipped - I'm talking about phase issues that result when summing two signals that are similar (i.e., originate from the same source) but that have either been mic'd/generated in stereo but in a manner that is not 'mono compatible' or been processed in stereo using algorithms that are not mono compatible. Some stereo signals will sum to mono just fine (for example, a mono signal that's been processed to a simple ping pong delay), but many will not - especially any that use phasing tricks to create a 'faux stereo' image. So if you know that all your stereo processing is mono summable - then great go ahead and sum to mono using a simple 2>1 mixer. But if not, it's more complicated to sum them without risking phase cancellation, comb filtering, or other undesirable artifacts.
I see what you're getting at. Some pedals may use algorithms that actually invert phase to get a semblance of wideness, or other tricks that may not be phase coherent and will cause comb filtering or some degree of cancellation when summed to mono. I hadn't thought about this; in this respect you would get a different - and less desirable - sound than just unplugging the right input/outputs and running in mono.

My stereo effects are eventide h9, timeline and flint. Hopefully they are true stereo I. This respect and will sum fine. I'll know when I hear it...
 

zwolf

Member
Messages
404
Received my summing box from T1M today. Works perfectly as advertised. Unplug the left output and you've got summed mono. Ping pong delays together out of one amp.

Furthermore, I went through each of my presets on the H9 and Timeline and messed around with a number of settings on the Flint. I compared each with just straight mono wiring to the summed mono out of the T1M box. I heard no difference and no odd phasey effects. I will say that I've been running in stereo for so long now that any kind of mono is sort of a bummer, but that's another story :)

Many thanks to Thiscalltoarms for bringing my attention to this super cheap solution. Box is TINY too, could go anywhere on or under a board. Sweet!
 

thiscalltoarms

more gadgets than Batman.
Platinum Supporting Member
Messages
8,155
Glad it's working for you! I am planning to one up in the Next few months when I re-organize my rig. Should be sweet!
 

rumbletone

Silver Supporting Member
Messages
7,392
Received my summing box from T1M today. Works perfectly as advertised. Unplug the left output and you've got summed mono. Ping pong delays together out of one amp.

Furthermore, I went through each of my presets on the H9 and Timeline and messed around with a number of settings on the Flint. I compared each with just straight mono wiring to the summed mono out of the T1M box. I heard no difference and no odd phasey effects. I will say that I've been running in stereo for so long now that any kind of mono is sort of a bummer, but that's another story :)

Many thanks to Thiscalltoarms for bringing my attention to this super cheap solution. Box is TINY too, could go anywhere on or under a board. Sweet!
Thanks for reporting back! Do you know whether there are electronics in it doing something to actively address potential phase issues, or is it just summing the L and R signals to one mono?

Sent from my Z10 using Tapatalk 2
 

thiscalltoarms

more gadgets than Batman.
Platinum Supporting Member
Messages
8,155
Thanks for reporting back! Do you know whether there are electronics in it doing something to actively address potential phase issues, or is it just summing the L and R signals to one mono?

Sent from my Z10 using Tapatalk 2
Pretty sure it's just summing to mono and is a totally passive device. Don't think it has a power jack...
 

zwolf

Member
Messages
404
Yep, totally passive. I expected to hear some cancellation issues with some of the stereo algorithms summed to mono but didn't. Pleasantly surprised!
 

baggas

Member
Messages
473
Received my summing box from T1M today. Works perfectly as advertised. Unplug the left output and you've got summed mono. Ping pong delays together out of one amp.

Furthermore, I went through each of my presets on the H9 and Timeline and messed around with a number of settings on the Flint. I compared each with just straight mono wiring to the summed mono out of the T1M box. I heard no difference and no odd phasey effects. I will say that I've been running in stereo for so long now that any kind of mono is sort of a bummer, but that's another story :)

Many thanks to Thiscalltoarms for bringing my attention to this super cheap solution. Box is TINY too, could go anywhere on or under a board. Sweet!


Thanks mate. Still waiting on mine to arrive, but the post is slow from America to Western Australia lately.

Really pleased to hear that it's working well for you. In the process of rewiring the stereo end of my board at present and my only question is whether or not to incorporate my Strymon Ola into the stereo chain, which would require switching the order of a couple of my pedals. Did you use any chorus or other modulate effects or just delays and verbs?
 

zwolf

Member
Messages
404
Wow - come to think of it, I don't have a single modulation based preset on the H9 at the moment, so I didn't test this with chorus specifically. However I do have some modulation on some of my ModEchoVerb presets, and plenty on a lot of my Timeline sounds and I didn't hear any problems with the summed signal. But I will test this when I get a chance, because it seems of all algorithms, it might be modulation based ones that would have the greatest likelihood of incorporating phase inversion tricks to add to the "wideness". I'll double check there's no issues with this.
 

Il_Falco

Member
Messages
58
I know im late to the party but couldn't you use a aby in reverse? Like a lehle sgos aby. If you use output a and b for the stereo in and input a for mono and input b for stereo i suppose it would work. I'm gonna try it and report back when i have the time.
 

minty901

Member
Messages
2,124
for this exact application i use a zoom ms70cdr. it has stereo ins and outs, but if you select a mono effect like the carbon copy, turn the mix to zero (if you dont want to utilise the delay), and then switch it on, it sums the signal to mono. this is a good option too because it still can sum even with two cables plugged into outputs, as i like to be able to use my small mixer at the end of my chain to control panning going into my looper. i havent noticed any difference whatsoever between true mono and summed mono, and thats from testing with tc electronic hall of fame, flashback, corona, and digitech supernatural.
 

ridgeroamer

Member
Messages
14
I haven't gotten one yet because board is in a state of Flux right now, but This1smyne does make a stereo sum pedal. It's $35 and it's in the Mooer size enclosure- it's the finger stereo summed mono option on this page:

http://this1smyne.com/shop/patch-bay/

Should work as long as the final stereo pedal has in phase stereo outputs, as the sum to mono keeps the reality phase of both feeds, so having both outputs out of phase would sound bad in a summed mono setup. I think Strymon pedals are all in phase on their stereo outs...

Ran across this thread. Checked out the website. Which model is the one you are talking about? This seems like a great option.
 

baggas

Member
Messages
473
You want "Finger patch stereo summed"

Although I notice there is now another interesting option with a toggle for summing. Wonder what the idea behind that is?
 




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