Transmission lines done correctly are very effective. Have you played with speaker placement? Another thing to keep in mind is Krell amps have an iron grip control on bass response, you'll get accurate fast bass, hard hitting, but no matter what you do you won't get rumble or flabby bass. The only way to get that would be through inflated settings of a sub. I could take Rap or Dance discs that would make car subs boom and drop them into my Krell system and the bass was there but it was so tight and controlled that the sound was quite different. As good as Krell is people who like that type of boomy bass will not like Krell. Krell plays extremely deep though with the right speakers. Put in something like the first track on Paula Cole and when that low frequency comes in it is amazing.