Re: FIR filters
Originally Posted by TJ Cornish
just 3 engineers passionate about audio trying to pick the system that sounded best in our space.
Jack,
You are "quoting" me and Evan out of context. IIRC, Evan encountered BMS co-axial compression drivers in a line array that uses a horns a fraction of the size used by you, Peter, and EAW, yet was crossed lower than any of you cross yours, with predictable results- it did not sound as good as a properly designed system would.
I have never stated that a cone will "always" sound better than a compression driver, and/or perform better than a compression driver. I have stated that cone mids can have far lower distortion at high output levels than compression drivers due to their much greater displacement potential, the opposite of what you imply, a compression driver may sound warmer, or more "phat" than a cone driver due to increased harmonic distortion. Given the same acoustical cut off, the diaphragm material makes no difference, any driver will sound "thin" with no lows. Turning off the lows does make HF distortion (and SPL) more readily apparent.
FIR cannot change pattern control (other than in multiple driver "beam steering") or distortion, but can smooth phase and frequency response. If the frequency and polar response of the SH-60 is similar to the SH-50 (the DSL spec sheet for the SH-60 does not even have an on axis response!), the roughness in both compared to the QX566i should be quite noticeable in an A/B test. The QX566i has four 12" LF drivers compared to the SH-60's two, giving it a 6 dB advantage, and a more sensitive mid/high section, also working to it's advantage in terms of headroom/distortion.
My first introduction to FIR was 2007, comparing a client's Mackie HD1521 to a DSL SH-100. The HD1521's flater frequency and phase response simply sounded better to the client and me, and the flatter response also allowed more gain before feedback. Although you can't replace basic good design with processing, that comparison made it quite apparent that the better processing FIR affords can make what seemed to be quite average components in a typical arrangement sound superb. Did not make a sale, but learned something that day. Actually, it was after that that I realized "Gunness Focusing" used FIR.
That said, it's been over a year now since purchasing a BSS Blu 100 capable of FIR, but I have still not got around to learning how to implement the filters on my system, maybe after I finish my center fill project.
The raw response of the center fills have almost flat phase response from 250, I'll be forced to implement FIR on the mains to align the two…
Art
