Open Sound Meter RTA/Phase/ETC Program

[Jdunk54nl]

I know @dumdum on here talks about using Smaart all of the time to see the phase and other cool and neat things. I also know some industry people use Smaart.

This seems like a cool free program that does quite a bit of the same:

https://opensoundmeter.com/

[dumdum]

It does indeed, I did look at it, it’s a bit clunky vs the demo version of smaart, you still need an xlr mic and interface with loop back facility, but free is always good!

[Jdunk54nl]

It does indeed, I did look at it, it’s a bit clunky vs the demo version of smaart, you still need an xlr mic and interface with loop back facility, but free is always good!

Nice! I am looking at a cheap option for macbook (and I've heard Asio4All on windows can do it too) of a simple cheap loopback device and a usb microphone. I will be testing this stuff this weekend and see how accurate it is between open sound meter and smaart di v2 (I finally purchased my own copy of it) and this method compared to using a motu m4 and xlr microphone.

In macbooks, you can go to the audio midi app and create a new "aggregate device" which can combine multiple devices to be seen as a single device as well as correct for clock drift. So far it seems to work, I can get all of the data this way (phase, magnitude, coherence, etc), but haven't had time to compare anything further.


The parts I am using for this "cheap" version:

External usb sound card: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

Headphone Splitter (I don't have this one, but any will work): https://smile.amazon.com/Headphone-S.../dp/B07431YDWM

2x Aux Cables

Dayton USB microphone


1) I plug the USB external sound card in and the usb microphone in.
2) I created an aggregate device combing these two items in audio midi.
3) I connected the headphone splitter to the usb sound card out. I then split that signal, using the 2 aux cables, with one going to the amp/dsp and one going to the usb sound card in.
3) In Smaart I set the device to my aggregate device.
4) I select output to the external sound card in the signal generator.
5) I set my measurement to the microphone and reference to the sound card mic in.

This allows me to see phase and all other measurements.

So in reality, if this does give good results, someone could get into this for about $15 more in cost for cheap sound card and headphone splitter with this free program instead of $900 ($600 for smaart di v2, $150-$230 for interface, $60 for cheapest dayton emm-6 xlr microphone)

[Jdunk54nl]

Here is some more on aggregate devices in both windows and mac and very basics on how to make them:
https://www.sweetwater.com/sweetcare...or-pc-and-mac/

[dumdum]

Nice! I am looking at a cheap option for macbook (and I've heard Asio4All on windows can do it too) of a simple cheap loopback device and a usb microphone. I will be testing this stuff this weekend and see how accurate it is between open sound meter and smaart di v2 (I finally purchased my own copy of it) and this method compared to using a motu m4 and xlr microphone.

In macbooks, you can go to the audio midi app and create a new "aggregate device" which can combine multiple devices to be seen as a single device as well as correct for clock drift. So far it seems to work, I can get all of the data this way (phase, magnitude, coherence, etc), but haven't had time to compare anything further.


The parts I am using for this "cheap" version:

External usb sound card: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

Headphone Splitter (I don't have this one, but any will work): https://smile.amazon.com/Headphone-S.../dp/B07431YDWM

2x Aux Cables

Dayton USB microphone


1) I plug the USB external sound card in and the usb microphone in.
2) I created an aggregate device combing these two items in audio midi.
3) I connected the headphone splitter to the usb sound card out. I then split that signal, using the 2 aux cables, with one going to the amp/dsp and one going to the usb sound card in.
3) In Smaart I set the device to my aggregate device.
4) I select output to the external sound card in the signal generator.
5) I set my measurement to the microphone and reference to the sound card mic in.

This allows me to see phase and all other measurements.

So in reality, if this does give good results, someone could get into this for about $15 more in cost for cheap sound card and headphone splitter with this free program instead of $900 ($600 for smaart di v2, $150-$230 for interface, $60 for cheapest dayton emm-6 xlr microphone)

curious... but not convinced as even minute clock differences between the two devices could cause grief, as umik-1 have had issues in the past with timing measurements

for me a Dayton xlr mic and a Behringer 1.5 channel (can’t recall the model no. But it had an xlr input and also a 1/4” Jack input also, plus 1/4” outputs too) it was mucho cheap!

[Jdunk54nl]

Ya. that is why I am interested to test. I have all of those things laying around from measuring impulse response of head units, so I thought they may work for this. I know my macbook has drift correction..not sure how well it will work. I will hopefully find time either tomorrow night or over the weekend to test this. I need to EQ my desktop speakers finally so this will be a great time to test all of this stuff.

[Jdunk54nl]

Played with this today. Seems to be pretty decent results. Definitely some clock drift issues above like 8k with the usb loopback, so using above that may get difficult.

This is what I am using:

Single I/O device setup:
Motu M4
Dayton Emm-6 microphone

USB devices:
Dayton Umm-6 microphone
External USB sound card
Headphone Splitter


Setup:




Note: These are without any microphone calibration files.

Smaart Results




Open Sound Meter Results: Was actually really easy to use, probably took less time to setup compared to Smaart.



Moral of this story...For $15 and open sound meter, you can get some decent results, especially below 8k. Above 8k, and you have clock drift issues. You could see the results kept changing every time the clock was adjusted. So if you want to use it above that, you'll need to invest more money.

[Justin Zazzi]

This was really fun to see today Jdunk.
That program is really impressive!

[Jdunk54nl]

Here are some final thoughts after playing some more with Open Sound Meter vs. Smaart. I have been playing with smaart only for a little bit (The demo then I purchased my own copy recently).

Initial measurement setup -> Open Sound Meter was easier
Changing setups -> Smaart is easier
Setting up and Measuring again -> Smaart is easier (it remembers and you can easily create pairs to switch)
Saving -> Smaart auto saves everything and recalls everything upon opening, Open sound meter doesn't even warn you before you exit....ask me how I know.


Overall Open sound meter works well enough if you are just tuning one thing and then putting everything away. It will take overall more time because you have to change all of the settings every time you open it. It doesn't remember if you unplug something. It does seem to remember if everything is ALWAYS plugged in. Like close it on accident and re-open without changing anything it will remember. Smaart just remembers all of your stuff everytime. I created a m4 and a usb sound card setting and switch between the two instantly when I was taking those measurements. Smaart always remembers your settings, probably that autosave everything.

Smaart has a lot of keyboard shortcuts that makes things super quick to measure.


So overall, I can definitely recommend open sound meter and if you aren't using it (even with a usb microphone and a cheap loopback device) you are missing out on very valuable information.

If you are going to be measuring a lot of different things, I would at least get a XLR microphone and something like a motu m2 or focusrite 2i2 and use open sound meter. I would even suggest purchasing Smaart di 2, it will save you a bunch of time. I will be using it when I teach waves and my wife is also a theatre teacher so will be showing her how to use it and her tech students for their shows. Smaart was worth the purchase for me for that stuff.


If you are just starting out in tuning, invest in a XLR measurment microphone like the dayton Emm6 and a device to interface with your computer. It might cost a little more upfront but so worth it compared to a usb microphone since you can use open sound meter with that and get useable results all the way up to 20 khz.
Dayton Emm-6
Focusrite 2i2 3rd gen refurb
Focusrite 2i2 2nd gen
Motu M2
Motu M4

A combination of the Dayton Mic and one of those interfaces would range anywhere from about $160-$300.

[BigAl205]

I was reading over the weekend the Focusrite Scarlet 4i4 has built-in loop-back, so you should be able to do impulse measurements without rigging up a cable and losing an input channel.