LTD02

the test signal is a constant sine wave, no? perhaps a 5-7 cycle tone burst would allow the amp to meet its spec?

Not sure what to say Luke. The specs on the website and in the manual sure seem to indicate 1200 watts per side at 4R and specifically stated are voltage and current limits that exceed that spec. I'm sure you checked, but maybe worth double checking again for any limiter that may be engaged?

the cc5500 was ~5300 watts both channels driven (bridged) through two drivers in series. the sp12000 was two channels each cranking 6148 watts for about 12,300 watts total through one driver per channel. the cc5500 hit 138.6db output. the sp12000 hit 139.0 output. those were the numbers that initially led me to conclude the ipal may be completely compressed out. but on second review and as others have pointed out the frequency was a little different. the low corner on the cab is right around there too, so it wasn't an apples to apples comparison.

i wasn't suggesting that you hadn't done it or didn't know. i was just laying out my logic. on second thought, in this test, doubling the current and doubling the power are looking at the same thing. [they probably always are, but with amps and speakers frequently folks refer to the "watts" as the volts/dc r not the actual, and varying, impedance.] as for testing the same freq., that might make some sense as the contribution from the room (and possibly the sensitivity of the horn?) may be a little different at the two different frequencies. with that much power compression, i'd be worrying about cooking the drivers. don't want to see that!

again, i'm a little foggy this morning, but i think you have to check the current for heating not the watts. 6148 w into 1.2 r is 86.5 v. 86.5 v divided by 1.2 r is 71 amps. one channel per driver so 71 amps through each driver. 5310 w into 4 r is 145.7 v. 145.7 v divided by 4 is 36 amps. drivers in series so 36 amps through each driver. with almost twice the amps, the spl at the listening position was 0.4db louder despite more than twice the watts, indicating almost total power compression past 36 amps. at least that is what i was thinking.

neat. if i'm interpreting the result correctly, the ipal's can't handle the current and compressed out almost all the power gains afforded by the sp amp?

since it was mentioned how much current the wall will allow and by extrapolation then the max power, that depends greatly on the "time current curve" of the breaker. they vary quite a bit. i just quickly searched on a ge 30 amp 240v breaker and was then cross-referenced to this link (ge industrial series ges-6112c available in amperages from 15-50, voltages from 120-240, and 60hz lines). it seems representative if not specific. http://apps.geindustrial.com/publibrary/checkout/GES-6122C?TNR=Time%20Current%20Curves%7CGES-6122C%7Cgeneric if the "bursts" that luke was drawing were less than one second in duration, the breaker may actually allow current to about 7 times its rating. for a 30 amp breaker that is obviously 210 amps. on a 240v line, that is 50,400 watts for a second. woohoo...

nice work josh.

road trip: https://sfbay.craigslist.org/nby/ele/4932551093.html

I don't know. you are pretty creative so there are many things your latest could be designed for on the inside. at high pressure, symmetry of output around the driver itself for balanced loading would seem to be among the next evolutions to minimize stress on the moving assembly and the cone itself. so perhaps some sort of cone shaped "plug" in front of the driver with exits on opposite sides of the 'loading chamber' that then combine into the throat of the horn? or maybe just a hole though which the air would be forced into the throat of the horn. that might actually be the simplest solution that provides balanced loading around the driver. seems like one of those powersoft magnetic linear accelerators attached at the throat of the horn could be something wicked. do they have a t&e unit that they could send you? that should be worth a cookie. ;-)

cool. it will be interesting to see how the amp/software deals with multiple resonance points. seems like it would need some sort of training and/or translation to know what to expect. have you experimented with it on a ported cab yet? i've read about the ipal system quite a few times and I'm still at a loss for what the practical benefit is of creating a synthetic t/s parameter set. the only thing that I can think of is that one could get the benefit of really good damping (massive bl/re) while offering a little more sensitivity* from an increased vas. but is that benefit really worth all the cost/complexity? i doubt you want to answer, but have you decided on a lower compression ratio on this one? ;-) * just above tuning in a ported cab.