Re: DFT, energy arrivals, and when to use SMAART vs. Systune
This is not entirely true. The energy is "excluded" by the nature of the averaging of uncorrelated signals across multiple frames. The shortest TC for Smaart 7 is approximately 7ms, according to Jamie. The more averages one does on the uncorrelated energy, the greater the SNR between the first frame arrival and the later frames. Within the TC of each frame, the uncorrelated late energy will increasingly be averaged to the background. FWIW, SMAART 7's direct arrival "window" in the 1kHz octave is functionally 35ish ms, or similar to the Hass fusion zone you mention.
This is utterly untrue, at least by the conventional definition of time-blind in the context of system measurement. An RTA integrates the energy of arrival over a given amount of time, but completely discards the phase information within each arrival bandwidth. You cannot capture the phase, and use it for your advantages, on an RTA. Because SMAART calculates a true H(f,t) by dividing against the reference signal.
If you have a late reflection in SMAART, its energy will manifest itself it both the phase and coherence traces, and those skilled in the art can quickly categorize the reflection as such. Similarly, if you have spectral contamination in the space from spurious noise, this can be readily ascertained. SMAART is not always the best tool for maximum noise immunity, but to say that is time blind is fallacious.
Or use Systune, if you care a lot about this. PS, Jamie assures me this "secondary" time windowing of the impulse response is most certainly in the works for SMAART 7, with no inherent limitations to implement it.
This is why I use both tools. SMAART is excellent at putting on the screen a great representation of how I perceive audio, but with much better phase and frequency sensitivity than I could ever claim that my ears have. As such, it is the right tool in my mind for tuning loudspeaker systems to spaces where people are going to listen reproduced audio.
Conversely, if am thinking like an acoustician, and need to know the magnitude spectrum of a 150ms late reflection so I can suggest the proper acoustic treatment location and type, then I'll window the impulse response where around the reflection in Systune, look at the reflection's magnitude response, and work from there. These are different tools for different situations.
Even further, I'll use Systune or an MLS-type stimulus (in Soundeasy) for characterizing loudspeaker behavior when I am designing loudspeaker processing parameters.
Different tools for different circumstances, and I remain firmly in the camp that SMAART TF mode is the clearest and easiest way to characterize with high resolution how people hear real sound systems in real spaces. This is what the Rational folks have designed to, and this is what they achieve very well. Their product also doesn't randomly forget its license, like Systune has done repeatedly for me.
For those that grok DFT, windowing, IR, energy arrivals, acoustics, etc. you can (currently) get more horsepower in this realm from Systune (or ARTA) than from SMAART. Systune is not for the uninitiated, but it is really powerful. Serious designer/integrator/installer-types should buy and dig into Systune, but the world's system techs should stay with SMAART.
More than 0.02,
