Richard Little
Stunt Coordinator
- Joined
- Jun 20, 2003
- Messages
- 105
then factor in the room nulls, then equalize the frequency response to get a smooth curve and your headroom could wind up in the craper. As a matter of fact, the 8 driver output of 121dB is reflective a SPL measurement taken at 1 meter (about three feet). Now each doubling of distance from the source reduces the measured output by 3dB (somebody correct me if I off base here), so at 4 meters (about 12 feet) which is a reasonable distance from the drivers to seating position, your down 6dB and back down to 115dB (at 20hz).
115dB (at 20hz) unequalized could result in 3-4dB loss in headroom when the FR is equalized. Add back in the possible room gain and you’re capable of 115dB from an 8 AV15 diver IB setup. I do not believe this is "new math" but more a function of physics. I haven't taken the time to double check the accuracy of the modeling software used, but am confident enough to say its close enough. I don’t mean to rain on anybody parade here. Chris, you asked a question, I answered it. I even gave a tangible example which appears to have sent a couple here into quite a tizzy. Other than the hole in the wall issue for some, I don’t see any other downside to IB’s.
Maybe that 15hz thing is the fly in the pie. Change your low cut filter to 20hz or 25hz and crank up the juice on a four drive setup (or two if it suits you) and reclaim output at the cost of extension. Model an IB and tell me what your findings are. Love to see what you come up with. I guess the only thing left to decide is “what would it take to get reference levels from an IB setup”. In the words a famous owl… The world may never know.
115dB (at 20hz) unequalized could result in 3-4dB loss in headroom when the FR is equalized. Add back in the possible room gain and you’re capable of 115dB from an 8 AV15 diver IB setup. I do not believe this is "new math" but more a function of physics. I haven't taken the time to double check the accuracy of the modeling software used, but am confident enough to say its close enough. I don’t mean to rain on anybody parade here. Chris, you asked a question, I answered it. I even gave a tangible example which appears to have sent a couple here into quite a tizzy. Other than the hole in the wall issue for some, I don’t see any other downside to IB’s.
Maybe that 15hz thing is the fly in the pie. Change your low cut filter to 20hz or 25hz and crank up the juice on a four drive setup (or two if it suits you) and reclaim output at the cost of extension. Model an IB and tell me what your findings are. Love to see what you come up with. I guess the only thing left to decide is “what would it take to get reference levels from an IB setup”. In the words a famous owl… The world may never know.
