Re: Frequency Response/Contour EQ in full range systems.
Hi Phil,
Thanks for passing on Jamie's comments.
For anyone interested, my summary of the topic is that the time window inherent in the DFTs in Smaart will not exclude late-arriving energy (reflections and reverb) from the transfer function magnitude display. People often castigate the humble real-time analyser for being "time blind", but Smaart's transfer function magnitude is equally time blind unless you specifically enable a time window (and then it will perform an IDFT to get the system's impulse response, truncate it at the specified time, and perform a DFT back to give the windowed magnitude response).
You (anyone) can prove this to yourself simply by changing the delay applied to the reference signal: the phase trace will change accordingly, the coherence may degrade (depending on the DFT size), but the magnitude response will just get noisier without actually changing.
To exclude late energy from a measurement in Smaart, use a DFT that's longer than the arrivals in question (not FPPO mode or whatever) and enable an explicit time window.
The question of whether it's useful really depends on what you want. As you know, human perception of late arrivals is a bit complicated with such phenomena as the Haas fusion zone. Sometimes you do want to see the direct sound from a loudspeaker and ignore the room.
Nick
