My measurements - looking for comments - Home Theater Forum and Systems - HomeTheaterShack.com
 
Thread Tools
post #1 of 7 Old 03-12-09, 02:11 PM Thread Starter
New Member
stangbat
 
Join Date: Apr 2008
Location: KC Metro
Posts: 4
My measurements - looking for comments

Edit: See Post 6 for correct frequency response measurements. Setup information in this post is correct, the plots are junk.
Long time lurker (almost a year), first post. I am slowly working towards an HT system. Right now I have added a sub to my 2 channel setup. I've been setting things up with REW and I'm looking for some comments about my measurements. Mainly I'm wondering if it looks like I'm getting valid measurements and doing this right.

Some information on my setup:
-2.1 channel, receiver is an Outlaw RR2150 which has built in bass management
-I can select sub crossover frequencies of 60, 80, 100 Hz. The crossover is 2nd order Butterworth. I have selected 60 Hz.
-My main LR are vented 3.5 way towers and have an f3 of around 41 Hz.
-My sub is a 15" Dayton RSS390HF, sealed in a 22" cube powered by an Oaudio 500 watt plate amp

General comments:
-I have calibrated my sound card, it looks good.
-I am using a "new model" RS analog meter. I am using the cal files from this site.
-I have set soundcard levels and calibrated the mic SPL
-No smoothing applied to the graphs

On to the measurements:

Mains full range

My measurements - looking for comments-01-mains-full-range.jpg

My comments:
-Huge room mode peaking at 47 Hz.
-I'm guessing the nulls are the room talking?

Mains with 60 Hz crossover applied. No sub

My measurements - looking for comments-02-mains-60-hz-cross.jpg

My comments:
-Seems like you'd expect more of a drop below 60 Hz? Or is my noise floor too high?

Sub by itself with 60 Hz crossover applied
Note: I have EQ a cut at 47 Hz to try and cancel the room mode from the mains. This is the reason for the dip at that frequency

My measurements - looking for comments-03-sub.jpg

My comments:
-I see more trash between 100-200 Hz than I'd expect with the 60 Hz crossover

Sub with mains, phase at 0 degrees

My measurements - looking for comments-04-sub-mains-0-phase-eq.jpg

My comments:
-Looks terrible

Sub with mains, phase at 180 degrees

My measurements - looking for comments-05-sub-mains-180-phase-eq.jpg

My comments:
-Looks much better

Sub with mains, phase at 90 degrees

My measurements - looking for comments-06-sub-mains-90-phase-eq.jpg

My comments:
-This is the best I've been able to get so far

What is funny is that with the sub, the first impression was that I have less bass. I had become accustomed to the huge room mode with the LR alone. Now that I can take it out, I have to get used to the "new" sound.

Thanks for looking. I appreciate any comments/suggestions/tips.

Edit: Sorry I left the mic calibration on the graphs. Oops.

Last edited by stangbat; 03-12-09 at 05:31 PM. Reason: Mic cal comment.
stangbat is offline  
Sponsored Links
Advertisement
 
post #2 of 7 Old 03-12-09, 02:33 PM
Elite Shackster
brucek
 
Join Date: Apr 2006
Posts: 7,514
Re: My measurements - looking for comments

Quote:
Mains with 60 Hz crossover applied. No sub
My comments:
-Seems like you'd expect more of a drop below 60 Hz? Or is my noise floor too high?
You simply do not have that set of mains crossed. That is full range, or your sub is on.

brucek
brucek is offline  
post #3 of 7 Old 03-12-09, 02:53 PM Thread Starter
New Member
stangbat
 
Join Date: Apr 2008
Location: KC Metro
Posts: 4
Re: My measurements - looking for comments

Quote:
brucek wrote: View Post
You simply do not have that set of mains crossed. That is full range, or your sub is on.

brucek
I just ran it again. Sorry, the graph is right. Sub is off, 60 Hz crossover set on the receiver. You can see there is a several dB drop between with and without the sub. But I agree it doesn't seem like as much as you should see. So I'm also wondering what is up. Maybe my noise floor is not low enough? Or I have something set wrong in REW?
stangbat is offline  
 
post #4 of 7 Old 03-12-09, 03:32 PM
Elite Shackster
brucek
 
Join Date: Apr 2006
Posts: 7,514
Re: My measurements - looking for comments

Quote:
Sorry, the graph is right.
Below is a 60Hz - 2nd order bass limited crossover target.

My measurements - looking for comments-mains-60hz-2nd-order.jpg

Below is your 60Hz - 2nd order bass limited crossover mains.



Something is not working or set in your receiver. It isn't REW or noise.

brucek
brucek is offline  
post #5 of 7 Old 03-12-09, 03:39 PM Thread Starter
New Member
stangbat
 
Join Date: Apr 2008
Location: KC Metro
Posts: 4
Re: My measurements - looking for comments

Quote:
brucek wrote: View Post
Below is a 60Hz - 2nd order bass limited crossover target.

Below is your 60Hz - 2nd order bass limited crossover mains.

Something is not working or set in your receiver. It isn't REW or noise.

brucek
Edit: Ignore below. I'm going back through REW calibration and I think I have it figured out. I'll post new graphs later.

Okay, here is why it looks like that. The following is my room with nothing on. You can see the slope of the graph with no noise follows what we are seeing with the response. It follows the inverse of the mic calibration? Why would it be doing that?

Mic attached, quiet, calibration file loaded
My measurements - looking for comments-quiet.jpg

Mic attached, quiet, no calibration file loaded
My measurements - looking for comments-quiet-mic-no-cal.jpg
-Still have a rising response on the bottom

Microphone removed, no calibration file loaded
My measurements - looking for comments-no-mic.jpg
-Same thing

Sound card looped back, no mic cal, C weighting unchecked
My measurements - looking for comments-loop-back.jpg
-Looks good

Last edited by stangbat; 03-12-09 at 04:13 PM.
stangbat is offline  
post #6 of 7 Old 03-12-09, 05:28 PM Thread Starter
New Member
stangbat
 
Join Date: Apr 2008
Location: KC Metro
Posts: 4
Re: My measurements - looking for comments

Okay, I think I got things figured out. I had to uncheck "Stereo Mix" in the input controls of my sound card mixer. So below are graphs of all my different trials, everything the same as described in the first post.

Main LR full range

My measurements - looking for comments-01-mains-full-range.jpg

-Big room mode at 47 Hz as to be expected

Main LR with 60 Hz crossover

My measurements - looking for comments-02-mains-60-hz-crossover.jpg

-Looks much better than in Post 1

Sub only, 60 Hz crossover, no EQ

My measurements - looking for comments-03-sub-60-hz-cross-no-eq.jpg

-Room mode still there

Sub only, 60 Hz crossover, EQ

My measurements - looking for comments-04-sub-60-hz-eq.jpg

-Now we are getting somewhere

Sub and mains, 0 phase, with EQ

My measurements - looking for comments-05-sub-main-0-phase-eq.jpg

-A mess

Sub and mains, 180 phase, with EQ

My measurements - looking for comments-06-sub-mains-180-phase-eq.jpg

-Still kind of a mess

Sub and mains, 90 phase, with EQ

My measurements - looking for comments-07-sub-mains-90-phase-eq.jpg

-Looking better

Sub and mains, 45 phase, with EQ

My measurements - looking for comments-08-sub-mains-45-phase-eq.jpg

-As good as I've been able to get with only having EQ available on the plate amp.

So I don't know if I'm going to get any better than this with the tools I have available. I do feel that from measurements, things look much better than with the main LR alone. I'll have to put in some listening time to verify.

One thing I noticed, having variable phase control made a huge difference in what I was able to do. A simple 0-180 switch wouldn't have gotten me anywhere. I would have had to move the sub all over the room instead.

Hopefully that wasn't too much of an ordeal. I feel like I figured something out. Comments are appreciated.
stangbat is offline  
post #7 of 7 Old 03-12-09, 06:25 PM
Elite Shackster
brucek
 
Join Date: Apr 2006
Posts: 7,514
Re: My measurements - looking for comments

I think it looks pretty good now.
brucek is offline  
Reply

Bookmarks

Tags
comments , measurements

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome