Cross-Spectrum Microphone Calibration Service - USA - Page 14 - Home Theater Forum and Systems - HomeTheaterShack.com

Reply
 
Thread Tools
post #131 of 368 Old 04-10-11, 09:38 AM
Senior Shackster
Michael
 
Join Date: Jul 2008
Posts: 142
Re: Cross-Spectrum Microphone Calibration Service - USA

Herb,

given that at 5Hz, the error range is 10db, what is the usable frequency range of EMM-6?
Also, taking humidity, temperature and other environmental factors, what would be the real-life precision of the calibrated EMM-6 across that range? Better than 3db? Better than 1db?
If I put the 'wind shield' on the mic, will it reflect the measurements?

thanks
michael123 is offline  
Sponsored Links
Advertisement
 
post #132 of 368 Old 04-10-11, 10:08 AM
Shackster
Tony
 
Join Date: Jul 2007
Location: Montreal
Posts: 14
Re: Cross-Spectrum Microphone Calibration Service - USA

Quote:
Anechoic wrote: View Post
However in room acoustics applications where the mic is picking up sound waves that are bouncing off the walls/ceiling/floor and arriving at the mic in arbitrary directions, the additional frequency response correction curves allow the user greater flexibility in using the mics. For room-correction/room acoustics applications, I typically recommend pointing the microphone straight up at the ceiling (with a slight tilt toward the main speakers) and using the 90-degree correction curve.
Received your 8000 a couple of weeks back and I am having a blast using it. I am using the 90-degree correction curve and pointing the mic up with a slight tilt towards the speaker I am testing. I wonder what kind of inaccuracies in the higher frequencies, if any, are there with the interaction of a hard (low, about 7 feet) surface ceiling. Perhaps I should use the 45-degree curve instead?

-Tony
distox is offline  
post #133 of 368 Old 04-10-11, 10:16 AM
Senior Shackster
Anechoic
 
Join Date: Jan 2009
Location: Springfield, MA
Posts: 397
Re: Cross-Spectrum Microphone Calibration Service - USA

Quote:
michael123 wrote: View Post
Herb,

given that at 5Hz, the error range is 10db, what is the usable frequency range of EMM-6?
I'm not sure I understand the question. With a correction curve, the usaable range is 5 Hz to 25 kHz. Without a correction curve, it's probably something like 80 Hz to 6 kHz.

Quote:
Also, taking humidity, temperature and other environmental factors, what would be the real-life precision of the calibrated EMM-6 across that range? Better than 3db? Better than 1db?
Environmental factors won't make a huge different unless you're using them in extremes (0 degrees F, 120 degrees F in the rain, etc). If you are using the mic in a standard comfortable environment (say 60-80 degrees F, 20-70% humidity), the differences in the mic response are on the order of tenths of decibiels.

Quote:
If I put the 'wind shield' on the mic, will it reflect the measurements?
The windscreen changes the response by about 0.5 to 1 dB above ~ 12 kHz.
Anechoic is offline  
 
post #134 of 368 Old 04-10-11, 10:18 AM
Senior Shackster
Anechoic
 
Join Date: Jan 2009
Location: Springfield, MA
Posts: 397
Re: Cross-Spectrum Microphone Calibration Service - USA

Quote:
distox wrote: View Post
Received your 8000 a couple of weeks back and I am having a blast using it. I am using the 90-degree correction curve and pointing the mic up with a slight tilt towards the speaker I am testing. I wonder what kind of inaccuracies in the higher frequencies, if any, are there with the interaction of a hard (low, about 7 feet) surface ceiling. Perhaps I should use the 45-degree curve instead?

-Tony
It's going to depend on how diffuse the sound field is in your room. If there's is a lot of energy coming from the ceiling, you might want to experiment with the 45 or 0 curves, but if the reflections are more random and coming in all directions, stick with the 90.

Experiment, and then figure out what sounds better to your ears.
Anechoic is offline  
post #135 of 368 Old 04-10-11, 10:39 AM
Senior Shackster
 
pepar's Avatar
pepar
 
Join Date: May 2006
Location: On an island
Posts: 108
Re: Cross-Spectrum Microphone Calibration Service - USA

Quote:
Anechoic wrote: View Post
It's going to depend on how diffuse the sound field is in your room. If there's is a lot of energy coming from the ceiling, you might want to experiment with the 45 or 0 curves, but if the reflections are more random and coming in all directions, stick with the 90.

Experiment, and then figure out what sounds better to your ears.
Is the orientation/cal used driven by the measurement being taken, e.g. 0° for the FR of an individual speaker, but 90° for decay/RT?

Jeff


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
is a neverending story!


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
pepar is offline  
post #136 of 368 Old 04-10-11, 10:44 AM
Shackster
Tony
 
Join Date: Jul 2007
Location: Montreal
Posts: 14
Re: Cross-Spectrum Microphone Calibration Service - USA

How do I know how diffuse my room is or how much energy is coming from the ceiling? I don't want to trust my ears first, I want to know what is correct, then I can tell my ears that it is correct and then choose what sounds good to me.
distox is offline  
post #137 of 368 Old 04-10-11, 10:48 AM
Senior Shackster
Anechoic
 
Join Date: Jan 2009
Location: Springfield, MA
Posts: 397
Re: Cross-Spectrum Microphone Calibration Service - USA

Quote:
pepar wrote: View Post
Is the orientation/cal used driven by the measurement being taken, e.g. 0° for the FR of an individual speaker, but 90° for decay/RT?

Jeff
Yes.
Anechoic is offline  
post #138 of 368 Old 04-10-11, 10:56 AM
Senior Shackster
Anechoic
 
Join Date: Jan 2009
Location: Springfield, MA
Posts: 397
Re: Cross-Spectrum Microphone Calibration Service - USA

Quote:
distox wrote: View Post
How do I know how diffuse my room is or how much energy is coming from the ceiling? I don't want to trust my ears first, I want to know what is correct, then I can tell my ears that it is correct and then choose what sounds good to me.
Diffuse means that reflections have an equal probability of coming from any direction and it's a matter of how reflective the surfaces in your room are. If you have an empty four-sided with a floor and ceiling, and all 6 surfaces are acoustically "hard" you can consider that to be a diffuse environment (for the pendants out there, I'm simplifying) where reflections will be bouncing around between the surfaces in all directions. At the other extreme, if the four walls and floor are completely covered in absorptive material (thick carpet, thick curtains, etc) but the ceiling is still acoustically hard, most of the reflections in the room will be coming from the ceiling and the room is not diffuse.

The 0-degree curve should be used when the mic is pointed in the direction of the sound source (or the reflection source if it's known and dominant). As the source of reflections become more spread out, you move toward the off-axis correction curves.
Anechoic is offline  
post #139 of 368 Old 04-10-11, 10:58 AM
Senior Shackster
 
pepar's Avatar
pepar
 
Join Date: May 2006
Location: On an island
Posts: 108
Re: Cross-Spectrum Microphone Calibration Service - USA

Quote:
Anechoic wrote: View Post
(for the pendants out there, I'm simplifying)
You probably mean "pedantics", but then I'd be one if I pointed that out.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
is a neverending story!


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
pepar is offline  
post #140 of 368 Old 04-10-11, 01:09 PM
Senior Shackster
Anechoic
 
Join Date: Jan 2009
Location: Springfield, MA
Posts: 397
Re: Cross-Spectrum Microphone Calibration Service - USA

Quote:
pepar wrote: View Post
You probably mean "pedantics", but then I'd be one if I pointed that out.
Touché
Anechoic is offline  
Reply

Bookmarks

Tags
calibration , cross-spectrum , microphone , service

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









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



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