I've had a constant problem with my GK1x12" NEO. The sound is not tight and the lower the note I play the more the sound distorts. There is also a constant hissing of higher frequencies. I turned the horn off, tried different speak-on cables, and finally replaced the driver with the correct driver from GK. All without any change or results. Any ideas what else to check? I am running my Mesa Subway in to the cab at very low volumes in y bedroom. The cab is set to Full Range. Thank you for any advice!