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I discovered an issue with my ZED and contacted tech support, here's how it went:

Let's say I have a backing track and a guitar. One channel is panned full left and the other full right. So while the guitarist is playing a solo intro on his channel, I'm noticing this odd bleed-like echo spilling over onto the backing track channel even though nothing is playing. I've attached a visual to show what's happening. The blue waveform on the bottom is the guitar soloist. The maroon colored waveform is the backing track, you can clearly see where it comes in. But during the solo, I'd expect the backing track channel to be silent... but it's not.

I've also attached an audio file that is playing just what you see in the maroon colored waveform. Have you seen this happen before? If so, do you know the cause, and more importantly the fix?

The guitar and rhythm section are connected to the inputs of the mixer. Channels are panned left and right. I have some built-in mixer reverb on the guitar channel, but none on the rhythm track channel. Main outs go to the video camera's XLR inputs and audio is recorded on separate channels. Video is imported into Sony Vegas video editing program and it generates the waveforms of each channel that you see in the image.

I've attached a photo of my ZED as it's currently configured.

Here are the replies I received from tech support:

Unfortunately, as I mentioned, the FX return is stereo, meaning regardless of what signal is sent into it, the output of the reverb will always be in stereo. This means that you are most likely hearing the effected version of the guitar on the rhythm track.

The only solution I can think of off-hand that should give you full separation between the tracks is to send the guitar track (with reverb) out of the left or right main, but then send the rhythm track via the aux, though it looks like the aux out is already being used. Another solution then might be to press the "record" button on the guitar channel and then use the left or right RCA "record out." As long as the record button is not pressed on the FX return channel, this should give you a clean output.


It looks like the only way to separate the reverb from the mic channel is to use the aux out for the guitar and reverb. Basically you will have the mic channel turned up as normal, and take the feed of the mic from the main L or main R. Then the guitar channel level control can be turned down, but the guitar channel FX send will be turned up. Then on the FX return channel you will leave the yellow "fx level" control turned all the way down, but the "fx to aux" control turned up. This should give you the guitar, with the FX, on the aux output, and keep the fx off of the main L or R where the mic will be output.

Unfortunately you would then need to fine a new output for the speaker, depending on what exactly you intend to send to that speaker.

This is unfortunately the only way I can reason to remove the FX from the mic, as the FX return is in stereo, meaning it will always be heard on both the main L and main R if it is turned up.

As you guys know from my previous posts, I'm not a guru with recording or mixers or any of this stuff. I just learn what I need to get the job done. The "solution" proposed by the tech is even more confusing to me than the problem. I bought the ZED because it appeared to be the least complex of the mixers available at the time, and could suit my requirements. Should I dump this mixer and go for something else? Or is this still the best thing going?

Thanks again for any suggestions.


Attached files maroon-waveform.mp3 (3 MB) 


Boswell Tue, 01/16/2018 - 08:14

Turn the stereo effect level to zero so there is no effect directly going to the main LR mix. Raise the level of the (mono) effect to Aux. Cable the Aux output to a spare channel's mono line input (this may mean moving the microphone XLR to channel 3 and using the line in on channel 1 for the Aux feed). Pan that channel to whichever side the guitar is panned to. Bingo - you have all the guitar plus effect on one output side. Make sure the Aux level is zero on all input channels. Where does your existing Aux output cable go?

That said, I don't understand why would you want to treat effected channels in this way. Using the main LR stereo output as two mono outputs is fine if what you want to do is record two independent mono tracks for later mixing. But effects should be added at the mix stage and not at the record stage. Supposing you don't like the type or amount of effect you have added - no chance of undoing it once it's printed. By all means use reverb or other effect in the monitor feed to the performer's headphones during tracking, but my advice is to record the guitar and backing as separate channels without any added effect.

MC208 Tue, 01/16/2018 - 10:43

"Turn the stereo effect level to zero" Is that the yellow FX level knob?

"Raise the level of the (mono) effect to Aux." Is that the gray knob directly above the yellow FX knob?

"Cable the Aux output to a spare channel's mono line input" I don't understand what you mean by this.

"Where does your existing Aux output cable go?" The aux output goes to the power head and then to the speakers so the guitar player can hear the backing track and guitar as he plays.

All I want to be able to achieve is to have control over levels that go into the camera, and separate control for the levels that the guitarist hears through the speakers. And have right and left separation of the guitar, and the track/mic channels. Ideally if there's some way to mute the mic when the backing track is playing (but I don't see a mute so I just have to lower the level all the way down, and then turn it back up when it's time to talk). I need the mic when the guitarist is talking and demonstrating something. The guitarist does not use headphones. The backing track already has reverb, I just need to add a little to the guitar so that it's not dry.

Boswell Tue, 01/16/2018 - 15:52

Yes, the yellow and grey knobs.

The reverb returns as a stereo pair of signals to the main outputs, but is summed to mono for its feed to the Aux output. It's this mono sum that you want to add to the guitar channel to prevent the spill into the vocal output.

You could split the Aux output to feed the amp as well, but I think you are creating problems having a loudspeaker monitor while you are recording vocals.

MC208 Tue, 01/16/2018 - 16:03

Do you recommend another mixer? If so, which one would make this easier?

The AUX out setup was another instruction from a previous post here on the forum some months ago. So the guitarist needs to hear the guitar and backing track on the loudspeakers, that goes out through the AUX, and then the Main XLR outs go into the right and left channel of the video camera. The mic and the rhythm track are panned left, and the guitar is panned right. I did this because mic and rhythm will never be used at the same time, only mic and guitar, so they are separate tracks in the video editor.

The only thing that's annoying is that the guitarist talks and plays at the same time, so the RODE mic overhead pics up not only his voice, but also the pick against the guitar strings. I wish it didn't happen, but it does, and I don't think there's anything that can be done about that.

MC208 Wed, 01/17/2018 - 09:17
  • Guitar
  • Peavey DPC-1000 Power Amp
  • PreSonus 2 channel BlueTube
  • Allen & Heath ZED 10FX Mixer
  • RAMSA WS-A80 speakers for monitor sound
  • MP3 Track
  • RODE NTG-1 Microphone
  • Canon XA10 Camcorder

I position the mic above (slightly out of the picture) and in front of the performer a foot or so. Speakers are about 8 feet in front of performer, and off to his right side.