DIY Speaker measurement

[nurmdog]

Helo All,
I've been reading reviews on this site for a year or so and just now registered. I want to be able to make some decently accurate measurements of speakers I have purchased and some of the speakers I have made. I apologize if this is not the correct or best forum to place this.

I own a Dayton Audio iMM-6 Calibrated Measurement microphone that I use with audio tools on my iPhone. So far the measurements of been like this, a manual process.

Put my iPhone on a stand about 1m from the speaker.
Use "level" to send a test tone at 1000hz, adjust volume until it reaches the expected SPL of the speaker at 1m (usually 88-91db)
Manually test various levels and write down the results (XLS). 20hz, 25hz, etc. Many manual data points.
Using XLS create a decent little graph of my results.


So this is far too tedious and time consuming, plus it's limited to SPL based on a cheap calibrated microphone with output from an iPhone.

Dayton audio makes USB calibrated mics and I have seen other things on the net.


To cut through the BS, what is the best lower cost setup I could use at home to measure speakers? I definitely need software and hardware both. I can spend a few hundred dollars, but cheaper is better. Cheaper leaves me with more money to buy and build more speakers. Thoughts? Thanks guys, love the site.

Nurmdog

 

[sweetchaos]

How to make quasi-anechoic speaker measurements/spinoramas with REW and VituixCAD

Quasi-anechoic measurements are a way to capture the 'real' frequency response of a speaker without the influence of a room. They are called 'quasi-anechoic' because they have the potential to get you really close to the results one might achieve with a non-reflective environment like an...

www.audiosciencereview.com

Plus a calibrated Umik-1 and you’re set.

Cross·Spectrum - Calibrated MiniDSP UMIK-1 Microphones for Sale

Purchase calibrated MiniDSP UMIK-1 measurement microphones, low-cost option for performing precise and accurate sound measurements

cross-spectrum.com

 

[nurmdog]

How to make quasi-anechoic speaker measurements/spinoramas with REW and VituixCAD

Quasi-anechoic measurements are a way to capture the 'real' frequency response of a speaker without the influence of a room. They are called 'quasi-anechoic' because they have the potential to get you really close to the results one might achieve with a non-reflective environment like an...

www.audiosciencereview.com

Plus a calibrated Umik-1 and you’re set.

Cross·Spectrum - Calibrated MiniDSP UMIK-1 Microphones for Sale

Purchase calibrated MiniDSP UMIK-1 measurement microphones, low-cost option for performing precise and accurate sound measurements

cross-spectrum.com

Thanks! I have read about REW some and wasn't quite sure how good it is. I will give it a try!

 

[Jdunk54nl]

I’d suggest a focusrite 2i2 or motu m2 and a emm-6 or similar xlr microphone.

You can reach the limits of a usb microphone, you can’t really reach limits from a xlr mic and interface. The xlr mic and mic interface allows for most software analysis too with loopback possibilities for real time impulse response and phase measurements.

 

[617]

For measurements a umik or umm-6 will work well. Most hobbyists use REW, there are good tutorials for it.

Learn about gating if you want to see quasi anechoic measurements of your setup.

 

[nurmdog]

So what about output? Is there a DAC/DSP of some sort that can be used to make a more reliable output audio? My MAC probably has decent output, and I definitely own a few DACs I have tried to use with it.

 

[Jdunk54nl]

If you buy one of the interfaces I listed above (focusrite or motu) they have output too. If doing on AVR, you will need an hdmi adapter most likely anyway.

 

[nurmdog]

If you buy one of the interfaces I listed above (focusrite or motu) they have output too. If doing on AVR, you will need an hdmi adapter most likely anyway.

Thanks, but I was confused about the mic you suggested. Isn't the emm-6 a USB mic? With those boxes wouldn't it be better to use an XLR mic?

 

[Jdunk54nl]

The emm-6 is a xlr microphone and the umm-6 is a usb microphone.
emm-6

Home

Dayton Audio EMM-6 Electret Measurement MicrophoneThe Dayton Audio EMM-6 is a precision electret condenser microphone designed for measurement and critical recording applications. The extremely flat frequency response and true omni-directional polar pattern make it perfect for use with room...

www.parts-express.com

umm-6

Shopping

 

[Jdunk54nl]

I have a couple umm-6's, an omnimic, and a couple emm-6's

If I am just checking something quick, I will pull out the usb microphone. But any critical measurements it is either the omnimic with the included omnimic software or emm-6(s) with Smaart or open sound meter and REW.

I am looking at an Earthworks paired set, but those get pricey and for what I do (mostly just hobby stuff), it doesn't seem critical for me to spend that money compared to the emm-6's

 

[617]

A usb mic should be able to act as an SPL reference, but a typical XLR mic cannot be used as an SPL reference, unless you know the mv/pa sensitivity of the mic and the exact amount of gain applied by the preamp/ADC.

I personally use an SPL meter and an XLR mic.

 

[Colonel7]

I’d suggest a focusrite 2i2 or motu m2 and a emm-6 or similar xlr microphone.

You can reach the limits of a usb microphone, you can’t really reach limits from a xlr mic and interface. The xlr mic and mic interface allows for most software analysis too with loopback possibilities for real time impulse response and phase measurements.

I'm going by things I wished I had from the start. If you have the budget don't cheap out bc a good measuring rig saves days of time, tedium and troubleshooting. A 2x2 interface is excellent advice. I would add DATS v3, an XLR mic and a scale that goes to tenths of a gram to measure T/S parameters. A decent extendable mic stand so that you can do gated measurements of various size speakers and a cheap but good amp of about 50 watts. Oh, and a bakers lazy susan for off axis measurements.

For software Vituixcad does just about everything but has a steep learning curve. I think not only REW but ARTA is worth learning and trying out depending on what you're measuring.

 

[nurmdog]

Thank you all, this great stuff . I’ll do some more research and see costs. I might start with USB mic and free software and consider adding a 2x2 and XLRs. My emotiva amp has an XLR input , so worth considering .

 

[nurmdog]

The emm-6 is a xlr microphone and the umm-6 is a usb microphone.
emm-6

Home

Dayton Audio EMM-6 Electret Measurement MicrophoneThe Dayton Audio EMM-6 is a precision electret condenser microphone designed for measurement and critical recording applications. The extremely flat frequency response and true omni-directional polar pattern make it perfect for use with room...

www.parts-express.com

umm-6

Shopping

Thank you for clarifying

 

[bigjacko]

If the usb mic can solve the timing issue, what will be the advantage to xlr mic compare to usb mic? JohnPM mentioned that using usb mic with a sound timing reference can get the accuracy to a few micro second, which is good enough for anything you will ever need.

 

[Jdunk54nl]

A huge advantage to an XLR microphone is real time measurements via loopback. No need to measure, adjust, check to make sure that actually adjusted properly, etc. Constantly updating with real time phase, impulse, magnitude, etc.

Also, if you have ever tried to use REW and getting good timing information, it is not easy via a usb microphone.

 

[bigjacko]

A huge advantage to an XLR microphone is real time measurements via loopback. No need to measure, adjust, check to make sure that actually adjusted properly, etc. Constantly updating with real time phase, impulse, magnitude, etc.

Also, if you have ever tried to use REW and getting good timing information, it is not easy via a usb microphone.

Thanks for reply, but as mentioned you don't need loop back to have timing reference. By having another speaker making a sound as timing reference is accurate enough.

 

[Jdunk54nl]

Thanks for reply, but as mentioned you don't need loop back to have timing reference. By having another speaker making a sound as timing reference is accurate enough.

Have you used REW to get good timing information to where your phase and impulse graph is accurate?
I have, and while you can get it accurate, it is a real PITA when using an acoustical reference. You also don’t get any coherence information, which is pretty amazing to have as well.

Like I’ve said, with a loopback, a lot of the issues are solved. Also the additional software that can take advantage of this loopback makes everything a lot easier. Open sound meter is free and gives you a taste of the software capabilities. Or watch some videos on YouTube about Smaart or even JL Audio and their new max tune system which utilizes smaart.

If you have used both styles of microphones, you would understand this and the ease of use the loopback brings to the table.

This I also a $200 investment for a xlr mic and interface compared to an $80 investment. Not a huge jump in price for a first time purchase, especially compared to what we spend on this hobby.

But at this point we are going in circles. If you haven’t used both, I encourage you to try it out by buying an interface and xlr mic and download open sound meter You will then understand what I mean.

 

[Jdunk54nl]

I also did make this post about how you "can" use a usb microphone with open sound meter to get a taste. You run into clock drift issues, but you can at least see what it is like to see this stuff in real time:

Open Sound Meter: A RTA/Phase/Magnitude/Coherence and some more Measurement Program

Learned about this today. Seems similar to some of the more expensive measurement programs (smaart, systune) with real time measurements via a loop back reference for Phase, Coherence, Magnitude, etc. Right now this is freeware much like REW. https://opensoundmeter.com/

www.audiosciencereview.com

 

[nurmdog]

Thanks guys, parts express had the umm-6 on sale for $70 and I purchased some tweeters I wanted, and threw in a $10 off coupon, so it was considerably cheaper than the mini dsp. Going to give this a go with the USB mic, I'm excited to see some results.