I recently purchased two GK NEO 2x10 cabs to go with my MB500. I've had them a couple of months now and haven't really had the chance to play them. Well, today I hooked everything up for a test drive as I have some gigs approaching. I was very dismayed to hear a worrying buzzing, farty sound coming from the cabs when playing - almost like a ripped speaker. It wasn't overpowering but definitely noticable. It was far more apparent with the boost channel engaged, but was there on the clean chanel too if I dug in hard. I tried each cab individually and it was the same sound from both cabs. It did seem like the buzzing decreased as I increased volume - that or the volume just overpowered it. However I couldn't push them too hard as I was practicing at home. For the record, I tested three different basses, both active and passive, and it was always apparent - although not as noticable when the -10db was engaged. I have also used the head through many other cabs and have never noticed the problem so I'm sure it isn't the head, and it's definitely not an inherent part of the boost sound. Also, although I never use the horns, I turned them up full just for a test and noticed that the farty buzz came out of them too. Is this a normal 'feature' of brand new GK cabs? I really hope they aren't faulty as I've thrown the boxes away... Starting to worry!