[SteveCallas]

Well I get back to Ilkka's comments about his testing - he ran his amp to clipping on the TC2k LLT, and it is supposed to be able to pump out ~2000 watts. He mentioned that he was unsure whether the driver bottomed in the 20-30hz range or if it was just the amp clipping, but either way we can say that 2000 watts was basically the point at which nothing beneficial could any longer be extracted from the driver. So I ask myself how did this happen (a lot of it we discussed in that previous thread)? Logical ideas mentioned were that the xmech on these type of high excursion drivers is quite a bit higher than the xmax, and that is true. Also, the suspension itself will begin to resist excursion a little bit beyond some unknown point.

I have never really been concened with bottoming a LLT below tuning due to a combination of electronics rolloff and the output levels demanded by movie scenes at such low frequencies, but I have worried about the range just above tuning. This is where the driver is still behaving almost identically to a sealed sub and excursion use can get quite high, and this is where I based amp limiting on. But I guess the combo of high xmech and suspension resistance beyond some point are enough protection in that range, making a LLT pretty bulletproof altogether. Ilkka also mentioned that you should be able to hear the driver in distress when it begins nearing xmech.

Then yes, there is the claimed vs actual amp output specs. While I really appreciate and admire the amp testing work Chuck has been doing at some other forum, I don't find it to be all that useful for actual subwoofer material usage. We don't sit and listen to 30 sine waves, music and movies are short burts of various frequencies. The amps he is testing can pump out a lot more clean power over shorter periods of time, so for real world usage, I'd say they can do even more than what they are rated for. His testing is more to see if the amps meet the claims of the spec sheets.