Automatically sum to mono

Thank-you for adding the Multi-out feature in firmware 1.0.3.

The only problem is that since I use a mono power amp for on-stage monitoring, this feature is really not usable in my setup without a stereo sum box. Ideally this setup should work with minimal extra equipment and cabling.

It would be great if there were at least one multi-out mono option, so I’ll propose the following additional output options:

  1. Multi-out 1/2, 3, 4 (I.e. 1/2 stereo, 3 & 4 summed to mono).

  2. Multi-out Mono (i.e. 1,2,3,4 available as mono).

There is a better workaround than this to send to an on-stage power amp.

Before your signal splits to stereo paths and / or reaches the main output, place an fx loop block in your chain where you want to send to your power amp (post effects but before your cab block) and choose the send 1 or 2 output in fx loop block’s settings. This will carry a mono signal and by default any stereo effects on a path before it are summed unless they have been panned or the chain has been split and panned.

This reduces the need to run a separate path just to get your signal to your on stage power amp, and frees up the main outputs for DI use.


That’s a pretty good idea, but unfortunately it doesn’t work for me as I’ve already accounted for those sends with a ZOIA in a stereo loop.

I have two inputs going in L & R and I would like these summed into a mono channel.


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Voted! I find the lack of available mono routing options the most inexplicable shortcoming of the QC right now (firmware ver. 1.40). There is currently no way to select multiple mono outputs from a single row without employing a loop send. You cannot select either multiple hardware outputs, or even just two mono main (Out1[XLR] & Out3[1/4"]) outputs simultaneously from an Output block.

There is currently no hardware option on the QC for auto-summing to mono by simply plugging into only the left output (1/4 and/or XLR), a dubious design choice from jump IMHO, but the way to work around it is to at least provide adequate mono routing options in the firmware. That doesn’t seem to exist yet either.

One of the most common scenarios for live usage is not available on the Quad Cortex - a serial path that uses all four rows to leverage max DSP, that then outputs in mono to an FRFR/amp on stage, and also sends a mono feed to the PA. There is nothing arcane or unusual about this scenario. A large number of performers use modelers this way, yet I cannot seem to easily do this on the QC. Why is this basic routing scenario still not available? I hope it gets addressed soon in the firmware.

All four rows are required to distribute/split the DSP load across all the cores for certain presets. It is not about needing to load all four rows up with 32 blocks. Utilizing all four rows in what another modeler company would call a “Super Serial (X4)” route, then requires that Row4’s output block offer the choice of multiple simultaneous mono outputs (it doesn’t). At the very least there should be an Output1 & Output3 option, such that a 1/4 cable can be run to an FRFR/amp on stage and an XLR feed to the PA.

It seems that the only decent alternative for running a serial route that uses all the QC’s DSP cores and also allows outputs to multiple mono destinations, is to place a mono block at the end of your signal chain. Then select the STEREO “Multiple Outputs” option for the output block in Row4. This is an exceedingly kludgy workaround.

All of these unnecessary gyrations are compounded by the fact that you can’t connect sequential rows together yet without using the splitter (which also has some quirks such as stranding the 8th block in rows 1 & 3).

If anyone has a more elegant solution to running a serial path using all four rows out to multiple mono destinations (that does not require employing a loop Send), please chime in. I am brand new to the QC and might be missing something. In which case, apologies in advance for the rant. I suspect it has already been brought up and is redundant anyway. I can see that Neural designed the QC with massive potential for routing flexibility. Just trying to add my voice to the din in requesting what seems, at least to me, to be fundamental functionality that is needed sooner, rather than later.


Just wanted to bump this topic as I consider it to be far and away the most glaring lack in the Quad Cortex. I honestly don’t understand why the vote count isn’t maxed out on this feature request. Is there another similar request? Is everyone running stereo when performing? Are users who are running mono rigs live, actually ok with having to insert a mono block at the end of the signal chain for every preset?

An option for both a summed 1/4 inch and summed XLR output, just seems to be a fundamental requirement for running a mono rig live and for this advanced a modeler. I honestly hope that this is a top priority for the 2.0 firmware release. This just seems so manifestly and obviously a major issue.

To me, this lack of flexibility is like Neural announcing that the QC is intended only for use in the studio or for stereo use ONLY, live. Either that or the QC is intended only for running multiple instruments, one to a row. Don’t mean to sound harsh but they have made it much more difficult than necessary to leverage multiple rows for a single instrument running in mono. This seems like an unintended consequence of not enhancing the output options. I am congratulating QC in advance if this is something they have addressed in the new firmware.

Also, on a related note, as I already stated above, I hope they fix the serial routing and dispense with the stranded blocks and inability to elegantly and easily send one row to the next. It should not be so involved and fiddley to run a mono extended serial signal chain.


Just wanted to revive this topic. I can’t agree more with the 2 last comments. In a live setup, it is crucial to be able to have the signal sent mono, for example to out1 AND to out3. Currently it is impossible.
And still, if it was possible, in my case it would force me to make a mono variant of all my presets to use in venues where they only give me 1 cable to the FOH.
The RIGHT way to do it is how the Helix (and I guess other modellers) does it, which is detecting if there is only 1 cable plugged to out1/2 and/or out3/4 and switch to mono automatically.
I am sure it is easy to do: the Quad Cortex already detects which inputs/outputs have cables plugged in (they show highlighted in the I/O section), so that is literally a few lines of codes away using those variables to switch the outputs either to mono or to stereo.
I hope NDSP realises that it is actually a quick win for a firmware update.


absolutely needed, voted


there’s a similar request that maybe a moderator could merge here:

Well, this is not the exact same request. The author asks for a stereo/mono switch in Global, while in this thread, I guess we ask for the QC to do it automatically if only one of the two outputs is used.
In essence, that is the same (be able to go mono on venues that do not offer stereo), but in how to implement it, these are two different things.


Yup, totally agree. Even my little 450€ AMpero Stomp ii would automatically sum to mono if it detected only 1 cable plugged in!


Actually, I have been researching a bit, and it is not as easy as summing to mono. Depending on the effects you have running, you might have phase issues, and possibly almost full cancellation of some effects.
So this functionality would actually need to be “intelligent”, meaning analysing your sound chain and “summing to mono” in the appropriate way.
This can lead to maybe things that are a bit more complicated than what we might have thought :wink:
I am not sure how other modellers do this, I never stopped thinking about how my Helix Rack does this: if it is “only” a sum to mono, or if it actually does something smarter…

Not sure if anybody at NDSP reads this forum, but I’d love to know their opinion on this!


I doubt that automatic switching can be added to the current QC as this would require circuitry that can detect a connection via mechanical switching or load detection. I think the best we can hope for is a global mono/stereo switch for each pair of outputs. BTW, automatic switching isn’t a “standard” feature on most processor. I’d estimate that less than half of the modelers I’ve owned have had this capability, probably due to the phase cancelation issues noted in gnumarco’s last post. To me, opening the connections page and clicking a switch would be no big deal.

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The qc does already detect whether an output is connected or not, if you open the global in- and output panel (swipe down) all outputs that are currently connected to something are highlighted. So that shouldn’t be the problem.

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You’re absolutely right. I’d forgotten about that feature. I retract my previous statement.:laughing:


The reason I’d prefer a virtual switch (instead of it switching automatically) is in the case where I want two mono outputs from a pair. Just me.


Very valid observation indeed.
So we would have a way to have 2 mono signals to send wherever we want. It is a good idea!

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finally what we need is an effective way to sum to mono, manually, automatically or both. the reason why I linked to @PickinPete 's topic was to avoid a scattering of votes between similar requests. any phase issue should be fixed automatically where possible or at least signaled by a warning.


I gotta disagree buddy. Something with the processing power the QC has should easily be able to work out which of its blocks are inverting or non inverting blocks, its doesnt need to do signal analysis, it already knows which are in or non-inv. And as I said; If my little Ampero Stomp II can automatically sum to mono when a cable is pulled then the Mighty QC should be able to do it in its sleep!

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This depends on how fast we would like the functionality to appear in the QC :stuck_out_tongue:
As you mention, the QC would need to maintain de property for each block to know if it generates phase issues if summed up to mono, and then process the signal accordingly. But I guess this takes some time to develop.