Waterfall Plot Q

[MichiganMan]

If I perform a basic sweep of the room I can generate a waterfall plot from the recorded data right? There is nothing extra you need to do when taking a room measurement to later generate the waterfall plot?

The reason I ask is that my frequency response looks good but the water fall shows little decay over time.

I'm adding room treatments so I expected this (slap/ringing) to some degree. But I wasn't sure if the reading I'm seeing is the true response or operator error.

[Wayne A. Pflughaupt]

The reason I ask is that my frequency response looks good but the water fall shows little decay over time.

Hard to say without seeing your graph, but at least one "gotcha" is the dB level being too low. If you have most of the graph above 75 dB or so you should be good. Of course if could be that you simply have a well-dampened room...

Start with a 5-600 ms window. If it appears that everything is decaying by that time, switch to a 300 ms window.

Regards,
Wayne

[MichiganMan]

Wayne A. Pflughaupt wrote:

Of course if could be that you simply have a well-dampened room...

Wayne,

It was actually the opposite, reflective. I have some treatments up so it's better. This is a sweep I ran a couple hours ago. If I understand the graph, I'm getting peaks at 21, 27, and 34 Hz. I'm crossing over (main/sub) at 80 Hz currently.

What can you gather from my plot?

[Wayne A. Pflughaupt]

Well, you don't have a lot of low-freq ringing, but then the overall level is a bit low. Looks like the only mode you have is at ~27 Hz, and a big depression between 30-40 Hz. Probably best to see if you can get a better location for the sub to deal with that...

Regards,
Wayne

[thewire]

The waterfall looks similar to me for when I had my subwoofers at each left and right wall midpoint. I dealed with the dips when I had them there by placing absorption at my left and right ceiling/wall corners, and by adding absorption to the front wall/floor corner. This however was rather sensitive to changes, and it results in some loss in decibals aprox 6dB. I found that the bass was good, but it required alot of eq that was rather difficult to deal with sitting so close between them as I was, and my problem was more to do with the front wall/back wall. I since dealt with the front wall and back wall some, but not tested the setup that way since.

When you are moving the sub if you do, it would help to see some different possible subwoofer positions and while knowing where it is.

[MichiganMan]

I don't have an EQ so I'll be limited to a resonance filter in my pre-amp, treatments and sub placement. I took quick readings at multiple sub placements. My room is imperfect so I'm just aiming for the best possible without spending alot of money.

[thewire]

It looks you are good shape there with those as far as placement options goes.