Tonal Issues

I’m having an issue with the sound from the QC, particularly through a PA. There’s a high end element to the sound that I just can’t seem to dial out without the signal becoming muddy. I need some help.

I’ve used the Global EQ to shelve 80hz and below as well as shelve from 9k but there’s a top end metallic type sound that persists. I’m primarily using captures and IR’s. The same thing is present with the stock models, too. Is there a known frequency that causes this?

Could it be the PA?

I would take that high shelf lower to like 6k.

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4k is a particular frequency that can be nasty to the human ear at high volume. Try a notch filter to bring it down a bit.


Are you hearing the high end problem on headphones or on other PA systems?

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Will try this. Thank you.

I’m not inherently hearing it on headphones but that output is handled differently and/or the headphones will have a different frequency response.

I’ve not tried through a different PA but will.

What are you using to monitor with on stage? Is your monitor also harsh? If not, you may want to modify the EQ on the PA rather than your QC. Tips below are intended for using the QC to tame the harshness, but the EQ suggestions can apply to a PA as well.

If this is occurring on every preset, you can use the Global EQ to address it. Otherwise, you can use a parametric EQ within the preset to locate the offending frequency first, and then notch it out. Either way the methods used below are pretty much the same for global or per-preset EQ.

Worth noting that if this is preset specific you may want to try modifying the mic choice on the cab or selecting a different capture before you modify the EQ. They make a huge difference to the tone.

Use a ‘Peak’ filter in the QC’s PEQ (or global EQ) with a relatively narrow Q and the ‘Gain’ parameter set high (+8db to +12db approx.) and sweep the ‘Frequency’ until you find the area where it is particularly harsh being even more exaggerated - set your cut there. You can also take the inverse approach and set the Gain to -8b to -12db or thereabouts, sweep and listen for where the harsh frequency starts to go away. Then set your cut there.

I have also found that it can be even quicker to use a more brute force approach with the PEQ. Just use the Hi Shelf (Low-Pass filter) to sweep down until the harshness goes away. You can leave it there if you still like your tone. Often it will be muddy or have lost some of the frequencies you want to retain at that point though and instead of just leaving the Hi Shelf parked there, you will want to move the Hi Shelf back up and instead use a Peak filter in the PEQ to notch out the harsh frequency you have just located. You may have to do this in a couple of locations to cut exactly where you find it necessary. Re-sweeping with the Hi Shelf each time to locate the harshness.


Thank you. I’ll try this, too.

I won’t completely know until I’ve tried it through a decent PA.

I had much the same issue. It was resolved for me by adjusting the high end on the pa chanel strip i was going into.