impulse response and more.....

[Kgveteran]

Anyone interested in some explaining inregards to Impulse response sweeps, interpreting graphs, and importing files for posting. I was asked in another forum to post a MDAT file, im totally lost with that one

[dcibel]

mdat is from REW software, not Omnimic.

[Kgveteran]

mdat is from REW software, not Omnimic.

Ok, that was easy enough, Ty. Im looking to treat my first reflection points. I dont want to kill the rooms sound, just those points inregards to the Main LCR. I have read enough to figure if im in the right spot on the wall and if there is sound reflecting through or around my absorber. Any advice would help.

Wts, im aware of the opposition to this, and there has to be a middle of the road between to much and none :0)

[dcibel]

I assume since you're in the Omnimic forum that you are using the Omnimic software for this purpose? The Omnimic provides a lot of data for this purpose. First is in the impulse response, which will show you individual reflections whose distance can be determined by the time of arrival. Often simply moving the mic around the room while observing the reflections in the impulse can determine their origin of floor, ceiling, wall, etc. Additionally, the Omnimic also provides ETC/RT60 charts and bass decay for observing room modes for the low frequencies. ETC/RT60 is well documented in the help file as well as other information available online. IMO the RT60 measurement is more suited to larger rooms for live events. Small rooms will generally have low reverberation simply due to the dimensions.

As for location your absorbers, the amplitude of the reflections as determined in the impulse and frequency response are a good indication of the absorber effect. Realistically, if you sit in the same location when listening, you can place a mirror on the wall where you can see your speaker in the mirror from your listening location. That will be the path of reflection, and a good starting point to locate an absorber IMO.

As a simple test of absorption, I would simply take a frequency response measurement of a speaker playing through the absorber (close mic), save the response. Then do the same without the absorber in place, keeping the volume and location of mic and speaker the same, then save the response again. You can load these 2 response files back in to the Omnimic software, and normalize the result to the response without absorber in place. This will show you the relative difference between the two measurements. Keep in mind that when an absorber panel is placed on the wall, the sound travels through it twice so the effect is about double of what you will see measured.

[dcibel]

To add another worm to the can, the power response (directivity) of the speaker IMO can have a greater effect on the sound (how the speaker illuminates the room) than added absorption panels, that is unless the room is abnormally reflective like an unfinished concrete basement.

[Kgveteran]

To add another worm to the can, the power response (directivity) of the speaker IMO can have a greater effect on the sound (how the speaker illuminates the room) than added absorption panels, that is unless the room is abnormally reflective like an unfinished concrete basement.

Here's a link to my build thread http://www.avsforum.com/forum/19-ded...-door-0-a.html. I've finished a bunch of stuff , i have to put finishing touches on the rolling door, the french door that lets all the light in, and acoustic treatments.
Im gonna be using 4"OC703(dual 2"), through testing using my OmniMic i can make them "just" big enough, i dont want to kill all the liveliness in the room. I have a vaulted ceiling that runs front to back that will need some serious attention.......

I know there is some opposition to treating first reflections, my thought is in a rectangle room with the reflection under 10ms, its clearly distructive.