I had to build/use an iso cab at our church. Here is a <link> to the iso cab build thread I started. Anyway, I have been not happy with the boominess of some chords, especially a G note on the sixth string. Ugh. I had tried 1x12's and 2x12's and it was just way too much for that cab. A month ago I decided to go with a Blackheart 1x10 extension cab, loaded with a Fane Medusa 10-75. I could not be happier. It sounds HUGE, and the boominess is gone. I can actually turn up the bass a little for power chords. I have also had more positive comments on my tone in these past weeks than ever before. If you have to use an iso cab, give a smaller cab a try. You might like it.