This weekend, I tried to use Ray LaMontagne's CD Trouble to adjust the bass on my RM40s. For the life of me, I could not get the right speaker to adjust correctly. Then, I turned off the left speaker and ran only the right speaker and got a somewhat OK result. I then turned off the right speaker and turned on the left speaker, but then was shocked at how much better the left speaker sounded, and that's without any tuning of the PR. I also found that the right speaker's bass and midbass were vibrating after the drum hit (or whatever the bass sound was), but the left channel didn't do this. I was freaking out, thinking that I did something wrong when I put in the RM40 upgrade. I even emailed Brian to see what the problem could be, and he and I discussed possible solutions.
Today, I switched channels to see if the boominess followed the channel,which it did. I was getting bummed, as now the entire system was suspect. I then switched sources from my Ack Dack to my Proceed AVP, with no change. I then tried a different CD and was surprised to find that the two channels were pretty similar. I've tried several other CDs and can't find any appreciable difference between the two speakers.
The moral -- watch what music you use to try to set the bass!
