Been a long time....but I still lurk here. I've been happily enjoying my 11.4.6 Trinnov Altitude system that Curt Hoyt and I calibrated, until I decided to do some measuring to try to tweak the subs for solving some niggling issues outside of Trinnov goodness. One thing led to another, so....
Just downloaded the latest REW build (version 5.19 beta 7, running under Windows 10, ASIO4ALL, etc.) and I have a few questions:
a) For comparing full-range speaker frequency responses, is the norm still to do 1/6th smoothing, or are the newer methods like variable smoothing, psychoacoustic smoothing or ERB getting some favor? Wondering because I did a search on the thread and I've read some comments suggesting that for determining EQ, you might want to use variable smoothing as it focuses correction better above Schroder, roughly speaking. Jerry's guide only mentions to "refer to REW Help". Has any closure come on this? And which method is "closest" to what we hear?
b) If you want to access the overall success of achieving a target curve, such as we'd draw in Dirac (or Trinnov, in my case), what smoothing is closest to determine the overall trend? Reason I'm wondering is that when I did some post-Trinnov full-range plots, with 1/6th or 1/3rd (ugh) smoothing, I have +/- 5 db or so variation in my speaker responses at 100 Hz to maybe 8 kHz, which used to fall within "acceptable" back when. However, that also washes out my implementation of a Harman curve, which is gently descending from about 100 Hz by about 4 db or so until we get to that 8 kHz. I'm wondering how I can best distinguish random variation due to the room from a trend in what I hear...
c) Waterfalls - is the 300 ms for "great" and 450 ms standard for "good" still the norm in practice, and has decay graphs been a more rigorous way to determine if there's ringing? Reason I'm wondering is I have <450 ms ringing at about 60 Hz on my L/R+Subs charts, representing about 15 ms difference between the plot and the decay at 160 ms. Not sure if this is an addressable problem or not, unless I find it's from my mains (meaning bass traps)? I have a pretty good speaker placement for Atmos with a 25-30 degrees placement, so I'm loathe to move the mains.
d) For more severe ringing - my sub response has a funeral pire at 600+ ms at about 40 Hz, which is also a null. Right now I have four corner sub placement, but I may look at switching out to midwall and see if it improves, as well as 1/4 and 3/4 length side positions. Anything I can do otherwise that’s practical there?
e) Distortion - anything I can do about 22% distortion at about 20 to 25 Hz short of giving up on low bass? My sub distortion is 5% or less everywhere else above 30 Hz.
f) Clarity - what the heck is anyone using it for? It sort of looks vaguely like what I'd expect a target curve to look like, but other than that I'm not sure if anyone has a standard response for "music" vs. "speech" clarity to look for
I'm eventually going to tackle SBIR with treatments and IR in general once I decide just how much of a Toolean I am about sidewall reflections, but for now the focus is the subs and getting my tonal balance down before I move onto Group Delay, IR and other goodies.
Audio Gear: Trinnov Altitude 32 (24 channel), NAD M27 amps (3)
Video: JVC RS600, Seymour 100" UF Screen, Lumagen Radiance Pro 4444 (coming soon)
Misc.: Oppo 103, Oppo 203 UHD player, JRiver
Speakers: PSB Imagine T3 LCR, Imagine T Wides and Side Surround 1, T2 Side Surrounds, Imagine XB rears, PSB CS1000 ceilings (6), HSU ULS-15 Mk 2 subs (4) - 11.4.6
Last edited by sdrucker; 10-06-2017 at 09:20 PM.