I personally think the “deeper bass” thing is a load of bollocks myself. Had an A4 and now on to the AK.

Soundwise I don’t notice anything, That isn’t to say there isn’t some possible refrinement in any of the frequencies - I just don’t notice it. So if there is such a thing as “deeper bass” in the AK it is marginal and of little note.

I do prefer the AK though. It’s basically replacing my trusted X-Station. Has a better form factor, fitting nice on my desk and switches into midi mode effortlessly. The added buttons make the functionality that little bit easier too.

What I would say is that outside of sale times I don’t think the AK is worth the step up from the A4. That’s just my opinion and not me bashing on the AK at all. I feel incredibly lucky to have got the AK for the price I paid for it (pretty much the current sale price for an A4) as the jump from A4 to AK wasn’t too big a deal.