Ideal USB cable length, streamer to DAC?

Someone on another forum whose name shall not be mentioned here tested a bunch and found the ideal length was the shortest possible. I believe the best was actually a USB-A connector attached directly to a USB-B but that's obviously not doable for most. I use a 6 inch cable because I can, but have not "tested" audiophile 6 inch cables against this one at that's going to be a custom order and not returnable if I hear no difference. I would imagine I will be in the minority with not using audiophile USB cables.

I have read USB should be under 2 feet, there was some gobble-gook about why. I never compared, but since a shorter usb is cheaper anyway, I went with the recommendation. 

Common wisdom is that shorter is better (for USB cables, at least).

My experience is quite opposite. I have directly compared, at length, in my system, 1m against 2m:

- Supra cable: the 2m one had stronger and more authoritative bass, more drive, perhaps more highs; the 1m brought the mids more forward, the mids were more colorful, more enticing and the highs might have been slightly more refined. Overall I preferred the 2m one but I could imagine systems and ears for which the 1m one would be better

- Curious cable: the 2m one was clearly better on all fronts, no contest. The main advantage was, again, bass and the impression of a more dynamic sound

@donquichotte Interesting - hopefully the longer cable works for me too - I just ordered a 1.8m USB cable from Zavfino - it's a standard length (returnable) and I assume (hope) there is a good reason why 1.8m is their standard length (other than it serves the average user in terms of distance between components).

The Uptone USPCB is ideal where it can be used, i.e. no cable but a printed circuit board. Otherwise a 10in Intona cable. Longer cables have reflections and may suffer from RMI/EFI incursions

Its quality, not quantity 😁

@kota1 and quality not $$$

I'm returning a $300 Analysis Plus Digital Crystal Cable (COAX) because the no-name USB cable supplied with the DAC sounded better. (I know comparing COAX to USB is not apples to apples).

We'll see how the Zavfino USB performs...the Uptone USB is interesting too....  

There is no direct effect on asynchronous USB delivered data, since no timing is involved (asynchronous), but there might be indirect effect by noise injected into DAC.  This noise might come from ambient electrical noise induced in the cable or computer electrical noise injected into cable.  In first case shortest cable is likely better while in the second case, when computer noise is injected, longer cable might act as a filter for very high frequencies.   What works for one person may not work for another - best to try.

@macg19 

I think an “ideal length” would be subjective in an audio situation but as long as the length supports the speed/bandwidth criteria I don’t see why it would matter.

USB 2.0 is supported up to 5 meters (16 feet) while USB 3.0 falls to 3 meters (under 10’) assuming these are not powered. It’s possible to add powered extenders but that brings in other considerations such as common mode noise.

I've used a 5M Supra USB cable without any issues:

Supra USB

helpful responses thank you all