"sum to mono" (very basic question)

[Errant Tiger]

I feel like I should know the answer to this, but I don't, so I'm asking, so I will.

If I had a pedal - say, a Mercury 7 - that takes stereo input via a TRS cable, then has stereo outs, and I run both outs (panning/regular) of my DD-5 into it, will it still pingpong?

Thanks!

[manymanyhaha]

Most reverbs aren't dual mono because they are creating/recreating a stereo field but the dry signal should. To a certain extent, you might here some panning in the wet signal of a Mercury7.

But the Polymoon and Enzo, yes. I use an EHX Mod Rex before my Polymoon and definitely, the panning comes through.

[whoismarykelly]

You're just working with a different connector format. You aren't summing to mono unless the pedal with the TRS in sums to mono.

[JonnyAngle]

You'll need a TS TS (2 plugs) on one end of the cable and TRS on the other end to keep the ping pong going.

Assuming the Merc7 is the last in your chain, you'll need to send each output to a separate amp

[Errant Tiger]

Yeah, I’m already running in stereo (two amps); I should’ve said. And I feel like I saw somewhere that the M7 sums to mono, so I wanted to double check the implications of that...

[lordgalvar]

Furtkamp would be the guy to talk to about that stuff.

I know some old racks sum a stereo signal to mono and the splits it again. It would change any panning or differences between the channels. The manuals should say if they are true stereo or not.

[Gone Fission]

It’s a later development to do reverb processing of a stereo input that preserves that some of the stereo image in the processed sound, not just the dry mix. I think even the big behemoth studio Lexicons didn’t do this until the 90s. PCM-70 is mono in, for instance. And my LXP-15 has stereo ins but the reverb sums to mono and stereoizes that summed input. World of pain if you’re trying to add reverb to processed sounds using phase inversion to exaggerate widening.

Manuals ought to have good info about the architecture of the signal flow in general and in the particular algorithms. If the manual doesn’t specify, it’s a warning. Look, mono sum is not the end of the world. (Ultra tap is mono some and is amazeballs.) But a company that doesn’t trust enough in its sounds and its users for full disclosure is suspect.

[whoismarykelly]

Furtkamp would be the guy to talk to about that stuff.

I know some old racks sum a stereo signal to mono and the splits it again. It would change any panning or differences between the channels. The manuals should say if they are true stereo or not.

It’s a later development to do reverb processing of a stereo input that preserves that some of the stereo image in the processed sound, not just the dry mix. I think even the big behemoth studio Lexicons didn’t do this until the 90s. PCM-70 is mono in, for instance. And my LXP-15 has stereo ins but the reverb sums to mono and stereoizes that summed input. World of pain if you’re trying to add reverb to processed sounds using phase inversion to exaggerate widening.

Manuals ought to have good info about the architecture of the signal flow in general and in the particular algorithms. If the manual doesn’t specify, it’s a warning. Look, mono sum is not the end of the world. (Ultra tap is mono some and is amazeballs.) But a company that doesn’t trust enough in its sounds and its users for full disclosure is suspect.

Rack gear isn't meant to be run in a chain like pedals so the idea of mono on the input/preserving a stereo spread generally isn't important. To manage something like a Lexicon reverb properly you would run your source into a mixer and then run a send from the mixer to each effect unit you want to use. Then the stereo returns come back and get mixed with your dry signal, which would generally also have its own speaker in a W/D/W rig. Rack gear is just an entirely different world of routing if you're doing it the way the manufacturer intends.

[crochambeau]

According to the Mercury 7 published specification available on their website it is stereo input and output, so you shouldn't have to worry about losing your image...

..unless there are algorithms that are so process heavy it needs to sum signal to one channel to get anything done. I doubt, in this day and age, that's an issue, but I've seen some old rack units (Eventide H3000 for example) that have a few effects algorithms that are mono when the rest are stereo due to processor limitations. A lot can happen in 30 years.

[Errant Tiger]

According to the Mercury 7 published specification available on their website it is stereo input and output, so you shouldn't have to worry about losing your image...

..unless there are algorithms that are so process heavy it needs to sum signal to one channel to get anything done. I doubt, in this day and age, that's an issue, but I've seen some old rack units (Eventide H3000 for example) that have a few effects algorithms that are mono when the rest are stereo due to processor limitations. A lot can happen in 30 years.

Thanks! I somehow missed this, or else read it and didn't understand it, which is also likely. I did send an email off to Meris and they confirmed that it would not be an issue.

Now I just have to scrape up the dough for the pedal...

[Gone Fission]

Rack gear isn't meant to be run in a chain like pedals so the idea of mono on the input/preserving a stereo spread generally isn't important. To manage something like a Lexicon reverb properly you would run your source into a mixer and then run a send from the mixer to each effect unit you want to use. Then the stereo returns come back and get mixed with your dry signal, which would generally also have its own speaker in a W/D/W rig. Rack gear is just an entirely different world of routing if you're doing it the way the manufacturer intends.

Preserving stereo spread is pretty important to me. I bought a line mixer with two independent stereo aux sends so I can take, let’s say, a stereo multi tap delay in parallel with a mono dry preamp out, run a Dimension-y chorus in the first aux, and a stereo input reverb in the second. A delay tap audible on the left would pull the reverb image to the left. If the manufacturers have stereo input algorithms, this is what is intended to be possible.

[rfurtkamp]

Almost all the older processors (rack and otherwise) that are "stereo" that are digital sum to mono internally on at least some of the presets. Sometimes it's a global thing (old Alesis rackmount pretty much anything, looking at you - they have stereo inputs but sum to mono at the input stage, and whether or not it's stereo again on the way out depends on the algo).

Sometimes they sum to mono with an effect on but go passthrough stereo if off, etc.

It's a case of read the manual and then test.

Not every manual is honest.

[zoooombiex]

Yeah, need to check the manual. I wouldn't assume just because it's a recent effect that stereo in's and outs means the channels are totally discrete.

E.g., Neunaber stereo pedals sum to mono for processing, despite having stereo ins and outs. But it's clearly described as such.

[Gone Fission]

Stereo reverb, if competent, isn’t dual mono. I’m sure some hack company will try to market that as if it’s a virtue at some point.