This was part of a live stream show on DJNTV: John shared how he solved a static problem with his Denon DJ MC7000 DJ Controller. When playing music, after about 1 or 2 songs there would be an increasing static or buzzing sound similar to a speaker distorting but at very low volumes. After testing a variety of possibilities (covered in the video) the problem was pinpointed and fixed with a firmware update.
Here is the controller: https://www.nlfxpro.com/dn-mc7000/
Here is the case: https://www.nlfxpro.com/prox-numark-xs-sx2mc7k-wltrb-case/
Here is the built proof Denon DJ Mc6000 MK2: https://www.nlfxpro.com/dn-mc6000mk2/
Here is the gaff tape used to support the MC6000 MK2: https://www.nlfxpro.com/nlfx-professional-platinum-series-gaff-tape/
How To Save The Day And Your @DenonDJ MC7000 DJ Controller Virtual DJ @VirtualDJ | Disc Jockey News