depth

Just some amusement for you chaps: It’s a JBL 2242 in a 6 meter long quarter wave enclosure with a pair of PD1850s in transmission lines. Bridged MacroTech 1202 for the JBL and a bridged CA6 each for the 1850s….. at least till one smoked and I had to change them for HK2400s. The mains were five Genalec 1038Bs. Also had a bunch of eminence butt kickers bolted to the floor which were quite fun. Theory says the rig was 3dB down at 13.5Hz. Don’t know how many dB we actually got though cos I couldn’t find a SPL meter with a long enough integration time and the right filter settings to measure that low accurately.

We had some problems initially with the whole thing vibrating back and fourth at really low Hz. We had to strap them all together, load them up with stage weights and strap them to the floor with 5 ton ratchets to keep the efficiency up. Setting the positioning and phasing right was a nightmare.

I know James hates Macrotechs but I think they’re the best amp going for subsonics. CA6s on the other hand are crap and blow up if you send them full power low frequency sine waves – CA9s do the same that’s the third one I’ve broke in exactly the same way, I don’t know why I expected them to do anything different this time, I think I’ll keep them for mids and highs only from now on.

We got some pretty extreme low frequency out of it all. The doors of the 150 seat auditorium flap back and fourth about an inch at 12 Hz. Playing “system check” by Brockie & Ed Solo was amazing and actually blurred my vision because my eyeballs were vibrating! We watched some films on the rig too after the gig and I’ve never really “experienced” film like that, bass notes and explosions kind of feel like they’ll keep on dropping deeper indefinitely. It’s the closest I’ve got to being able to reproduce things like thunder and fireworks accurately. Still not quite right but you defiantly get more of the depth and physical sensation of the real thing. I spose you start to run into problems with the mics and methods used to record them in the first place when it’s that deep.

I know it’s not a remotely fair comparison but in this application the JBL absolutely beat the crap out of a pair of 1850s. The 2242 is an incredible driver but very hard to get hold of and ridiculously expensive over here. Mine was a lucky ebay find, I’ve got a genuine recone kit and I’m waiting for a blown one to turn so I can get another cheap. Problem is they don’t seem to blow up very often!