Home Theater Forum and Systems banner

1 - 6 of 6 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1 (Edited)
Hello,

First post here just wanted to thank the creator(s) of REW Wow what a cool program.

After a few hours of playing with it last night and again today I think I have gotten some accurate measurements (as accurate as possible with my equipment any way.)

A quick rundown of what I am using, the Radio shack digital spl meter (using the calibration file found here), and a Creative XFI Platinum. I do not have a mini to rca female adapter at the moment so I am using the digital SPDIF out to my receiver, however I do have a mini to rca male so I did the sound card calibration with analogue out to aux in, but I am actually using digital out for output I hope this doesn't mess with the sound card calibration.

I have just moved into my first house and built my first home theater, the room is not ideal but it works good for seating of 3.

My front L/R are Definitive 7004's running as large/full range until I can afford a nice subwoofer.

As you can see in the cad drawing I have built 2 absorption panels for the first reflection points on the left and right walls, the one on the right wall is a little different however, it extends an extra 6" back because of the way the wall is. They are filled with 4" 3lbs Knauf rigid fiberglass but sit right against the walls. Not in the cad drawing is a 4'x5' window that I have also built a panel for when using the room, it only has 2" of fiberglass.

My issue right now is around 130-160hz. I have ran some tones and walked around the room, it seems like they are propagating in the open closet in the back of the room but not really any where else.

In the response plot the Grey line is my base line with just my 2 panels on the walls. I then added a box that has 3 2" sheets of insulation plus about 5 couch cushions :nerd: It seemed to help a little but not much.

I'll get some pictures of the room up as soon as I find my camera but from this info what suggestions do you guys have.

Bass traps in the front two corners is not going to work for me as those speakers are bipolar and I do not want to mess up the response of the rear array.


Thanks,

Cameron
 

Attachments

·
Registered
Joined
·
2 Posts
Discussion Starter #2
Ok I was wrong about the sound being loudest in the open closet, I was using pink noise with a low pass of 140 and a high pass of 190 when I heard that.

I switched to a sine wave of 155hz, the deepest part of the valley and wow is it amazing how much of a change there is while moving around the room. it is loud in each corner , but it is very loud near the ceiling in the corner where the room gets slightly wider (not at the back wall). it is also very loud just a foot or two outside of the open closet.
 

·
Super Moderator
Joined
·
9,257 Posts

Welcome to the Forum, Alaskan!
I switched to a sine wave of 155hz, the deepest part of the valley and wow is it amazing how much of a change there is while moving around the room. it is loud in each corner , but it is very loud near the ceiling in the corner where the room gets slightly wider (not at the back wall). it is also very loud just a foot or two outside of the open closet.
Yeah, it’s typical for bass to be more intense near boundaries...

Regards,
Wayne
 

·
Registered
Joined
·
678 Posts
... My issue right now is around 130-160hz. I have ran some tones and walked around the room, it seems like they are propagating in the open closet in the back of the room but not really any where else. ...
Have you tried taking measurements laterally, left and right of your listening position? Looking at your diagram, it appears as if you might have the absorption panels at the first reflection points that correspond to the nearer speaker, but that they are not far enough toward the couch to cover the first reflection point from the far speaker.

The test for this would be to look at the sweeps of the speakers individually, and then move the microphone laterally. Obviously approaching the wall would increase the direct distance from the opposite speaker, decrease the distance to the wall, decrease the difference in the path distances, and increase the frequency at which you see destructive interference from the reflection.

Regards,
Bill
 
1 - 6 of 6 Posts
Top