First measurements....Need help making sense of the graphs.

[busdriver13]

Hi all. I'm just getting my system situated and took my first measurements. The room is 22L x 18W x 8H. I have acoustic treatments form GIK acoustics. Each corner is treated with soffit traps, I have (2) 244 bass traps behind the listening position on the back wall, and (2) 244 on the front wall behind the speakers, 2 at first reflection points and 2 mid wall. Any advice would be greatly appreciated. Thanks.

 

[DanDan]

REW has become very complex as more and more features were added. It' pretty much an Acoustic Lab now, so put on that Lab Coat and Safety Glasses!
There are plenty of Primers and Guides, but of course mine is the bestest by a bigly shot. https://www.avnirvana.com/threads/some-guides-to-rew-and-acoustic-measurement.121/page-2#post-49827
For now I note that you don't seem to have much Bass. Perhaps there was a High Pass Filter somewhere in the Recording, REW, chain?
I recommend moving the speakers to kiss the front wall. Remove those 244s temporarily so we can have almost contact. Might help with the LF.

 

[busdriver13]

Not that i'm aware of. The subs are crossed at 100HZ. All other settings are normal or off. No tone controls or anything. Where could I find if there was a high pass anywhere in the chain?

 

[DanDan]

No pasa nada.... you will get into it. The subs must have been omitted from the sweep. You are about 40dB down at 30Hz.

 

[busdriver13]

I have REW set to start from 10hz-20000 hz for the sweep. So you're thinking it's a processor setting or in the REW settings? When playing music, the subs are working.

 

[JStewart]

The subs must have been omitted from the sweep.

Sure does look that way. With XO at 100hz .

@busdriver13 , a couple quick things I noticed.
1. The sweep level is 115dB. If correct that's much much louder than needs be.
2. It appears the UMIK 90degree cal file is being used for the computer sound card calibration file. If I'm correct that will throw off your readings.

 

[DanDan]

+1 The Cal file needs to be applied to the Mic. That would probably explain the HF boost and the very odd level. In REW/Preferences/Soundcard/Input Options, there is a HPF available.

 

[busdriver13]

Thanks fellas. As soon as I can make some noise ill make those changes and post the new measurements.

 

[busdriver13]

Alright, I think I fixed it thanks to you guys. Here are the new measurements.

 

[busdriver13]

Anybody??

 

[DanDan]

LOL, the world has in fact ended busdriver. It's just you and me. I'll get back to you lat.......

 

[busdriver13]

Hahaha. Too funny. Thanks for the help!!

 

[DanDan]

Well, there we go. I see big nulling around 50Hz, it would probably be worth moving the subs about to see if you could minimise that.
Open to debate here but I reckon that subs can be turned sideways to get the cone much nearer to the wall. Or even pointed at the wall or floor, with an air gap obviously.
Your measurement facility is now functioning, so try the things I suggested early,

 

[busdriver13]

Thanks!! Been playing with things but it's a pain moving these things around. I moved the speakers 6 inches back from the original position. That puts the face of the driver 43 inches from the back wall and side of the speakers 30 inches from the side walls. I also moved the rear soffit traps to the front corners and one horizontally behind each speaker. The listening position is 9 feet away from the face of the drivers, 7 feet from the back wall, and speakers are 8 feet 4 inches apart.

 

[DanDan]

I am not sure what back or front means here. My way is to call the Front Wall, well, the Front Wall. There are speakers and subs here right? Which is where? Why place traps behind the speakers?

 

[busdriver13]

Yea now that I read it, it wasn't very clear. So the front of the speakers are 43 inches from the front wall, the sides of the speakers facing the side walls are 30 inches away and the speakers are 8 feet 4 inches apart. I sit 9 feet from the speakers, the back wall is 7 feet behind me.. The speakers are on top of the subs. It's an RBH SVTR.

 

[Jon330]

Watch this tutorial and it will help you greatly!

 

[Nordo]

Yea now that I read it, it wasn't very clear. So the front of the speakers are 43 inches from the front wall, the sides of the speakers facing the side walls are 30 inches away and the speakers are 8 feet 4 inches apart. I sit 9 feet from the speakers, the back wall is 7 feet behind me.. The speakers are on top of the subs. It's an RBH SVTR.

A plan of your room layout with dimensions might help.

 

[busdriver13]

Here is my best attempt at being an artist!! I moved the speakers a bit and managed to get better measurements. Don't understand why the roll off at the high frequencies except that I was running the test generator via airplay to a Bluesound node2I.

Room is 22 feet long. The drawing appears to show 27 but is 22' long.