I have one of the Rumbles that probably gets the least love here in our little club, the mighty Rumble 15. It's actually a great little amp other than the unworthy speaker. Anything past halfway and it rattles. I've pulled the speaker out and kept it away from the amp and it is definitely the speaker. Yesterday, I ordered a Pyle PPA8 8" speaker. It's a 200 watt RMS woofer with a 60-5000 Hz frequency range. I also have the 100 and 200 Rumbles for stage and home recording studio, but the 15 gets the most playtime. I'll give an update after it gets here and is installed. For $33, it should be a worthwhile investment in a great little amp.