Measuring basics - microphone/computer questions

#1
From what I can see Jim Smith first determines the seating position that'll be out of room nodes, then places speakers for maximum musicality. My Wilson setup guy has not done this step in the past, but he is still able to get amazing sound in any room. Since I've done the big remodel, I have several feet fore/aft that I can move the listening position and want to avoid nodal peaks. Obviously half-way between the front and rear wall would not be the correct spot! :)

In my room I have computer/DAC. The computer is a custom built small profile fanless design with SSHD. There is no room to add a sound card, I am forced to use the onboard Realtek drivers with a microphone. The computer has a ASUS Gryphon Z97 Socket 1150 Intel mobo.

Can I just get a calibrated USB microphone, load software like Room EQ Wizard, play some pink noise or test frequencies, and be good to go for taking basic measurements? (Most of what I've read says I'd need a dedicated soundcard?) There would of course be some assigning of inputs to get things right, yes?
 
#2
Bump
 

PeterA

Active Member
Dec 7, 2011
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#4
I used a $10 app for my iPhone from the app store

It's called Spectrum Analyzer from ONYX Apps
Steve, just looked this up. Do you use a special mic for better results? It is hard to tell how accurate it is. Can you tell us a little bit about how you use it and how helpful it is in your system?
 

Steve Williams

Site Founder, Co-Owner, Administrator
#5
Steve, just looked this up. Do you use a special mic for better results? It is hard to tell how accurate it is. Can you tell us a little bit about how you use it and how helpful it is in your system?
Hi Peter

I never used any mic other than that on my iPhone. I used it to give me an idea of how my room measured at the listening position as well as when I made any changes in the room. I'm sure others will say it isn't accurate or that there are better and more accurate to which I agree. As I said it gives me an idea of how my room measures when I play some pink noise
 

Barry

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#6
<< Can I just get a calibrated mike....?>>

Yes, use REW and you will need a mic. REW downloads are at Home Theater Shack website. Amir posted some helpful starting tips here:

http://www.whatsbestforum.com/showt...rial-for-Dummies-Part-1&highlight=Room+wizard or go to HTS website here:

http://www.hometheatershack.com/forums/rew-forum/

Takes a little learning time but once you get the hang of it, it's well worth it. For speaker set up a laser distance meter is invaluable.

Have fun and good luck!
 

ddk

Industry Expert
May 19, 2013
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#7
From what I can see Jim Smith first determines the seating position that'll be out of room nodes, then places speakers for maximum musicality. My Wilson setup guy has not done this step in the past, but he is still able to get amazing sound in any room. Since I've done the big remodel, I have several feet fore/aft that I can move the listening position and want to avoid nodal peaks. Obviously half-way between the front and rear wall would not be the correct spot! :)

In my room I have computer/DAC. The computer is a custom built small profile fanless design with SSHD. There is no room to add a sound card, I am forced to use the onboard Realtek drivers with a microphone. The computer has a ASUS Gryphon Z97 Socket 1150 Intel mobo.

Can I just get a calibrated USB microphone, load software like Room EQ Wizard, play some pink noise or test frequencies, and be good to go for taking basic measurements? (Most of what I've read says I'd need a dedicated soundcard?) There would of course be some assigning of inputs to get things right, yes?

You should be able to clearly hear the difference in your seat position and if you can't or it's all the same why bother with measurements? Just move the chair and your head back & forth and pick the spot you like best.

david
 

RayDunzl

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Jun 26, 2014
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#8
Can I just get a calibrated USB microphone, load software like Room EQ Wizard, play some pink noise or test frequencies, and be good to go for taking basic measurements?
Yes, but, REW will work best if it is able to send its own test tones (logarithmic sweep) to the system.

What outputs do you have?

You could use Optical/Coax, USB, or HDMI digitally, or an analog output (which might be noisy, depending on circumstances).

I use an on-motherboard Optical out for the test tones and a UMIK-1 for capture.

I find it quite useful.
 
#9
Yes, but, REW will work best if it is able to send its own test tones (logarithmic sweep) to the system.

What outputs do you have?

You could use Optical/Coax, USB, or HDMI digitally, or an analog output (which might be noisy, depending on circumstances).

I use an on-motherboard Optical out for the test tones and a UMIK-1 for capture.

I find it quite useful.
What do you send the optical out to? I send digital out to my DAC via USB. (Fogive my ignorance please.)
 

asiufy

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Jul 8, 2011
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#10
Hi Bob,

My only tip would be to be careful with the sweeps, when doing the measurements, as some tweeters will not like that much energy going through them very quickly. Give it a minute or two between sweeps just to be on the safe side... And of course, mind the volume :)


cheers,
Alex
 
#11
Hi Bob,

My only tip would be to be careful with the sweeps, when doing the measurements, as some tweeters will not like that much energy going through them very quickly. Give it a minute or two between sweeps just to be on the safe side... And of course, mind the volume :)


cheers,
Alex
Thanks Alex, good to know. I'm mostly focused on low bass response looking for best spot to place my chair. Are there low frequency sweeps or tone styles to avoid... I would expect you could also damage a woofer?
 
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#12
Thanks Alex, good to know. I'm mostly focused on low bass response looking for best spot to place my chair. Are there low frequency sweeps or tone styles to avoid... I would expect you could also damage a woofer?
You shouldn't be using any real power for the sweeps. You should be able to do the sweeps at your listening level or maybe a bit higher. Just use some common sense and you should be fine. One thing to avoid is if your speakers have reflex cabinets don't go to far below the tuning frequency of the cabinet. Bellow the port tuning the output is falling quite quickly. At a couple of watts you won't damage them but you unload the driver and loose any dampening the box provides so the excursion rate can climb quickly. So if they rolloff at 40 hz just keep an eye on the woofer if the sweep runs down to 20hz as an example.

Rob:)
 

asiufy

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Jul 8, 2011
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#13
Thanks Alex, good to know. I'm mostly focused on low bass response looking for best spot to place my chair. Are there low frequency sweeps or tone styles to avoid... I would expect you could also damage a woofer?
Hi Bob,

Usually the sweeps are full frequency, to measure response/reverb time in the room, not frequency response. But you can do low frequency sweeps as well! I think generally tweeters heat up faster than woofers, that's why, depending on the volume you're hitting them, and how frequently you do the sweeps, the tweeter might overheat and die...

I agree with Rob's answer below, that you should be careful with the volume. But depending on the size of your room, and how much absorbption and/or background noise you have, you might have to kick it up a notch to get the mic to pick up enough at your listening/measuring position. It's very easy to run that sweep 3-4 times within a few seconds, just to get a baseline, and that might be enough for the tweeter to overheat...