All your base are belong to us

Im still blown away by the super bowl performance. The star spangled banner by Reba who’s from my home town and then another twister movie. Why we keep making movies about twisters rather helping the buffalo heards grow preventing tornados in the first place is beyond me. We can all thank the government for that. 

While the audio installation market shrinks the tour industry grows however its not growing its just getting larger. Being as im the resident unappreciated expert id like to point out some basics of audio which are likely ignored by well, everyone.

Three metrics completely ignored by well, almost everyone, Impedance of loudspeakers, STI and LEQ.

How one measures impedance on a powered loudspeaker ill never know. What is impedance used for, well. In short it answers the question, is there a hole in the wood loudspeaker? Are the drivers in tolerance of specification. Now an expert will design a system capable of doing just that with one mouse click. Sadly we still don’t have this automated for larger systems. The only one close would be assumed Clair Cohesion, but Clair doesn’t share much with folks like me, actually Clair refuses to even talk audio with folks like me, maybe because they don’t do audio. Maybe because they are in the tucking industry and im in the audio industry. Their words not mine.  Sadly Don Pearsons website has been taken down and only geeks like myself and others have copies of his papers saved offline. He took the time to explain B & K’s impedance rig and iv certainly built maybe about a dozen rigs or so. Later one would get the Linear impedance rig and then a small usb impedance rig for windows. One can also use Lab.gruppen PLM amplifiers. 

STI is speech intelligibility of which I think the stadium industry will keep secret the real metrics of these giant sound system and acoustical environments. One simply plays the STIPA signal and analyzes it with any of the tools available or creates an impulse response. Care has to be made if using the impulse response measurement. One has to measure below the noise floor and then add back in the calibrated noise.

Lastly LEQ. It literally helps one decide if for example its say Metalica, can I play Enter Sandman over and over with three other songs, and if so what are the three other songs whith out impending or exceding the LEQ values. This in my opinion with the giant playback rigs used for live audio replacing actual talent is more important than one could imagine, in my opinion. Once upon a time I had a Qsys rig built for this but no one was interrested. Not even QSC ;-(

My last rant about tour audio is simply, not enough measurement rigs, not enough complex measurement rigs and almost none of the measurement rigs are calibrated, or used properly. Also rarely does one see an SPL or working SPL meter sitting on the FOH desk. Case in point how many B & K piston phones are on tour, answer, likely none which is a damn shame. How many 4007’s with proper mic clips are being used, likely maybe one but a whole measurements rig worth, well no one takes audio serious enough to make that kind of investment. Also how many Lectrosoncs transmitter controller remotes are on tour? I can only think of two or three. Literally, more Lectro measurement multi channel rigs, the better tours sound simple as that. 

As I continue to be the un appreciated expert I must ask others what they think of my tour limitations and would like to know more thoughts on giant tour systems from the field and wish everyone a safe and happy tour. Not joking Tinitus is a pain in the ass and not many folks are talking about actual SPL strategies that I know of let alone a subwoofer strategy.