Room acoustics


How about a thread on room acoustics and ways to improve the in-room performance of your system and its speakers? Subjects covered could be the physics of room response, measurement of response in your own room, and how to deal with imperfections, above and below the Schroeder frequency, like damping, bass traps, speaker positioning, (multiple) subwoofers, and dsp equalization. Other subjects could be how to create a room with lower background noise for greater dynamic range, building construction, or what to do in small rooms.
I am a bit busy just now, but as soon as I have time I will try to kick off with some posts and links.
willemj
I agree it regards to treating the room, not the signal. But I'd imagine both are valid solutions with their own particular compromises. 

The waterfall graph is exactly what I've been looking at.. a very useful data visualization. What is considered an acceptable decay time for bass? I've also discovered a dip at 2k.. hmm
I’ve yet to build one, but for bass absorption, the limp membrane trap seems ideal. A member on here also recommended it to me, without me having mentioned that's what I was considering.

https://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/743040-tims-limp-mass-bass-absor...
All right y'all, I've posted some interesting waterfall plots on my systems page.  Check them out.  There are three measurements:
: The first is my room without any extra bass treatment, other than the bass panels behind my speakers and the acoustic panel stuck in the corner.  You can see the bass is a mess and there is a nasty frequency around 120 that lasts forever.  That would be the one-note bass i've started noticing.
: The second is with a big, potted orange tree in the corner behind and to the left of my left speaker.  There is a three panel glass sliding door on the left wall. You can see the bass is much cleaner, the bass that didn't want to die is now dead and the whole graph is much cleaner.
: The third is with a quick limp membrane bass trap I whipped up last night.  I used some dynamat i had from a car install to cover the top of a 5 gallon bucket, with a blanket thrown in to stop it all rattling on the tile floor. As you can see, it's not as clean as the orange tree, but the one note bass isn't there either.  The midrange region is definitely a bit dirtier than with the orange tree, but it's better overall than having no extra bass treatment. 

The orange tree is, oddly, the best sound treatment for my current issues. Ha! The problem is that it is sitting outside right now so it gets more sunlight so the oranges can ripen and in the summer it's outside all the time.  This means I'll need something that can either be a permanent part of the room or that i can move in when i move the tree out.  I thought I was just dealing with bass decay problems, but it looks like that corner gets a lot of midrange reverb, probably from the large amount of glass right there.  Curtains aren't an option. We have a clean look and blinds would make it feel cluttered and small, a problem in a basement with 7 foot suspended ceilings..