HD videos is great. Vocal audio is pretty good but perhaps a tad low in areas at times. Kinda loud to me would be hearing it very clearly on about 15-17 volume on a Windows machine. Banner is ok but I would advise you to come up with a slogan and a schedule to be placed in the banner. A schedule overall would be helpful to any viewers of potential subscribers.
A review of mine in return would be helpful

I'm MusicForTheDay and I run a channel that features a daily show highlight a variety of quality free royalty-free music pieces for project/video content creators like yourself! Have a quick look and you may find something. A review of the brand, thumbnails, video format and editing would be helpful. Hopefully you like the 3D audio spectrum for viewer experience