Originally Posted by sdrucker
Originally Posted by AustinJerry
I thought you would follow the Guide, Brian. A waterfall measures modal ringing, and really does't show much of anything of value above 300Hz.
We have been using 15-300Hz on the horizontal scale, 40/50 -100dB on the vertical scale, and between 450ms and 600ms for the time window. Your waterfall doesn't look good from 100Hz down. Perhaps it is just the graph. Please repost a waterfall using the L+R+subs with Audyssey on, and using the guidelines I just mentioned. That will give us a better view. I would start with 600ms.
I thought we were aiming for 450 ms as "silver" and 300 ms as "gold"? What would 600 ms be - a "bare minimum" for an untreated room (like mine)?
BTW if Jason's right about REW somehow measuring slightly below the noise floor by about 10 db, the difference between using 45 and 50 db as the lower range of the vertical scale sure makes a difference for me. At 50 db, I fall about 2-3 db from the lower extreme. OTOH, at 45 db I have a ringing problem between 50 and about 90 Hz, as the waterfall decays to the very bottom of the chart. That's at 450 ms. At 600 ms, my entire range from about 50 hz on, except for an artifact at 200 Hz, is also 2-3 db minimum from the bottom, but there's consistently more room above the bottom of the chart. Same data, different presentation.
The goal is to be able to see everything decay (by 60db) within 300ms for the whole range 20hz to 20khz but since that is very difficult, for the modal range (15hz or 5hz or whatever to 300hz) this goal is relaxed to 450ms.
However, if with your graph set to show 450ms you still cannot see the tail fall below the floor then you need to increase it to whatever it takes to see it disappear which could mean 500ms, 600ms, 800ms, etc.
Compare this with the Spectogram to see where the tail ends to make sure the graphs agree.
So everyone's display before treatment or as they are working on it will be different. We want to see all the way to the end though and not just have the "mountain" hit us in the face.
Only when we are finished with the treatment will the window fit within 300ms to 450ms and the tail truly fall below the noise floor.
If we limit the graph to 300ms or 450ms and it doesn't show everything, then how do we know how bad it is or how much more work we have to do??
I'm glad this got brought up because it appears everyone is setting the limit to 450ms or so which is really only appropriate if you can see 50-60db fall into the noise floor within 450ms and for the most part, I'm not seeing that and cannot get a grasp as to how bad things are (how long they TRULY ring) because the limit stops too soon. Does that mean there is ringing to 650ms, 870ms, etc? Who knows.
And what do you mean, "If I'm right!!"