What does ESS hump do to sound signature?

[LimKimPork]

Hey guys I have some questions about ESS hump.
I am currently running Sabaj D5 with THX 789 stack.
I was looking at reviews here and many times I see "ESS hump"

I assume the ESS hump is a type of distortion that the ESS DAC chip creates
but what does it do to the sound? does ESS hump audible distortion? or
it's something like "distortion is there but it's not really audible and you can avoid it if DAC is designed well"
I am a bit confused cuz some of Amirm's listening test saying DAC is super clean and clear even if there is ESS hump

 

[somebodyelse]

It's an odd pattern in the IMD vs. level plot that shows up only in some DACs using a subset of ESS chips. I'm not aware of anyone having done the listening tests to determine whether it's audible, but based on audibility thresholds it seems unlikely for most people since even the 'bad' part of the line is well into the 'probably inaudible' zone. The designer from Soncoz has shown how careful choice of components after the ESS output can get rid of the hump, while E1DA's designer has shown how some of the configuration choices can affect it. Some other designers clearly know how to avoid it too, but haven't shared the details of how they do it. "distortion is there but it's not really audible and you can avoid it if DAC is designed well" seems about right.

 

[bravomail]

tend to agree that it's probably "inaudible", but why take risks?
ess humps ur IMD graph!

 

[FrantzM]

Serious answer: Nothing audible.

Peace.