First measurement, which smoothing to use - Home Theater Forum and Systems - HomeTheaterShack.com

Reply
 
Thread Tools
post #1 of 13 Old 11-16-13, 06:03 PM Thread Starter
Shackster
 
Join Date: Feb 2012
Location: Va
Posts: 63
First measurement, which smoothing to use

I want to make sure I have everything setup correctly, not sure what smoothing to use. Also do I need to adjust the room size or mic distance from speakers?

Here's my first measurement using 1/3 smoothing.

When I calibrated my soundcard, I had the laptop volume at around 35%, however when performing tests the volume was too low from the speakers...I had to raise to 88% to achieve 75db on the SPL meter. I trust this doesn't affect anything.
Attached Thumbnails
First measurement, which smoothing to use-test1.jpg  

adauphin is offline  
Sponsored Links
Advertisement
 
post #2 of 13 Old 11-17-13, 08:04 AM
HTS Senior Moderator
 
Wayne A. Pflughaupt's Avatar
 
Join Date: Apr 2006
Location: Corpus Christi, Texas
Posts: 9,172
Send a message via Yahoo to Wayne A. Pflughaupt
Re: First measurement, which smoothing to use


One-third or 1/6-octave smoothing is fine for full-range measurements like you’ve posted. It gives you a better idea of what response actually sounds like, compared to a scary smoothed graph that looks like a ragged mess. However, for a subwoofer-only graph (typically zoomed in to 15-200 Hz), unsmoothed works better for those.

Regards,
Wayne



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
|
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

Wayne A. Pflughaupt is offline  
post #3 of 13 Old 11-17-13, 08:37 AM Thread Starter
Shackster
 
Join Date: Feb 2012
Location: Va
Posts: 63
Re: First measurement, which smoothing to use

Thanks, I was searching around and found most used 1/12, would this be too much for living room, full-range measurements?

I also have the mic pointed straight at about a 20 deg upward angle.

Here's a shot of the Preferences tab, just making sure it's correct. For the microphone I use the default or should I select Microphone, or does it matter?



The graph I was using was 'ALL SPL", all are useful but for this discussion is this the one to use? Basic questions I know but hopefully it will help others as well.
adauphin is offline  
 
post #4 of 13 Old 11-17-13, 12:43 PM
HTS Senior Moderator
 
Wayne A. Pflughaupt's Avatar
 
Join Date: Apr 2006
Location: Corpus Christi, Texas
Posts: 9,172
Send a message via Yahoo to Wayne A. Pflughaupt
Re: First measurement, which smoothing to use


Personally I think 1/12-octave is too fine for full-range measurements, but naturally others have their preferences.

Frequency response measurements with the mic upright should only be used with a 90-degree calibration file. Even then you can get skewed results, depending on your room. You can’t go wrong by using a 0-degree calibration file and pointing the mic at the speaker being measured. At least for full-range frequency measurements of the main channel speakers - with subwoofer measurements, it doesn’t matter where you point the mic. Also, an upright orientation is fine for generating acoustics-related measurements – ETC, impulse response and so forth.

Regards,
Wayne



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
|
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

Wayne A. Pflughaupt is offline  
post #5 of 13 Old 11-17-13, 01:29 PM Thread Starter
Shackster
 
Join Date: Feb 2012
Location: Va
Posts: 63
Re: First measurement, which smoothing to use

The testing I'm performing now is for room acoustics and absorbing panel effectiveness. Does this require an upright orientation and is there a calibration file for this?
adauphin is offline  
post #6 of 13 Old 11-17-13, 01:39 PM
HTS Senior Moderator
 
Wayne A. Pflughaupt's Avatar
 
Join Date: Apr 2006
Location: Corpus Christi, Texas
Posts: 9,172
Send a message via Yahoo to Wayne A. Pflughaupt
Re: First measurement, which smoothing to use


Yes, the upright position is best for acoustics- related measurements; no calibration file needed.

Regards,
Wayne



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
|
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

Wayne A. Pflughaupt is offline  
post #7 of 13 Old 11-17-13, 03:50 PM
REW Author
 
JohnM's Avatar
John
 
Join Date: Apr 2006
Location: UK
Posts: 6,707
Re: First measurement, which smoothing to use

Quote:
adauphin wrote: View Post
For the microphone I use the default or should I select Microphone, or does it matter?
You should select 'Microphone', otherwise REW cannot access (and adjust for) the input volume setting when showing SPL.
JohnM is offline  
post #8 of 13 Old 11-17-13, 04:37 PM Thread Starter
Shackster
 
Join Date: Feb 2012
Location: Va
Posts: 63
Re: First measurement, which smoothing to use

Quote:
JohnM wrote: View Post
You should select 'Microphone', otherwise REW cannot access (and adjust for) the input volume setting when showing SPL.
Ok....will do.

I have read conflicting reports on using the SPL, I assume this is with an external card. I set the level by watching the SPL until it reaches 75 db *- 1db, however I dont have it connected to the MIC input of the laptop. Should I use this in conjunction with the UMM-6?
adauphin is offline  
post #9 of 13 Old 11-17-13, 04:42 PM
REW Author
 
JohnM's Avatar
John
 
Join Date: Apr 2006
Location: UK
Posts: 6,707
Re: First measurement, which smoothing to use

The UMM-6 cal file usually includes a sensitivity figure which REW can use to show SPL based on the UMM-6 input alone. There are varying reports on whether that works properly though, no problem with reading from your external meter, particularly if you have calibrated the REW SPL meter to read the same. You don't need your external meter to be connected to the laptop.
JohnM is offline  
post #10 of 13 Old 11-17-13, 05:03 PM Thread Starter
Shackster
 
Join Date: Feb 2012
Location: Va
Posts: 63
Re: First measurement, which smoothing to use

Quote:
JohnM wrote: View Post
no problem with reading from your external meter, particularly if you have calibrated the REW SPL meter to read the same.
This could be something I need to address....I used the laptop to raise the volume and set the speaker volume to 75db at the listening position, with the preamp at -2. The meters on the REW are not indicating 75db though, however that is the SPL at the mic.

Do the meters in REW for checking volume need to indicate 75db?
adauphin is offline  
Reply

Bookmarks

Tags
measurement , smoothing

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