Low sustain


I’m the proud owner of a brand new QC.
I need a little help :
Sustain of my guitar is quite short and far more shorter than on my amp, whatever preset i choose, even with no elements
I use the same guitar, cable pick etc…
(fender Jag or Gibson HB same pb)

What could I tweak to improve it

I double check input level / output
maybe impedance but I tried every values with no improve

thanks for your precious help

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That is going to be mostly subjective but NDSP has recommended to leave the master volume at 100% as it acts as an attenuator and provides the best SNR at 100%. From there you need to tweak presets/captures to work and sound the best for you. I am not sure how you have your QC set up for playing but as an example etc., I have my rig setup using QC XLR outs going to PA/FRFR and OUT3/4 going to two separate power amps which gives the best tone possible for me. You could adjust impedance but I usually leave that at default and it usually doesn’t make much of a difference unless I am running active pickups. So it depends on how you have it setup for audio. I would set your amp up with the best tones, get the sustain where you like it and capture that tone and then compare the capture with the reference tone.


I forget to specify that I work with the headphone

If you are just using headphones for audio, then try capturing your amp and compare using your headphones. My guess is you might need some EQ blocks added to your preset to adjust for the headphone frequencies etc. This would be validated if you made a capture and compared to the reference tone. Worst case if you are unable to determine a solution, reach out to NDSP via support@neuraldsp.com and they can get you resolved quickly. Also, don’t forget to adjust your headphone levels on on the QC as well.

Well, if you play a real amp with a speaker (that moves air), this will excite the strings and let them ring longer (feedback). When you play the QC through headphones, no air movement to excite your strings → less sustain.

You can compensate for this a bit - if you know how to operate and tune a compressor, you can get better sustain on headphones, also on clean tones…

yes for sure
but I’m a quite intrigued because with plugs like Neural DSP or even Guitar rig I get better sound quite longer (maybe they include a sort of invisible compressor on input ?)

Hmm, then that sounds like an issue of input level. Are you sure you have set the input level high enough for your guitar on the Quad Cortex?

Lots of good tips on this here already, e.g. regarding using a compressor, and the impact of what you are using as a monitor. Here’s another possibility. A lot of the factory presets have a noise gate enabled. If the noise gate is set up with too aggressive a setting for your rig it can squelch your sustain. You can test this by turning the gate block off, and checking to see if your sustain improves.