Using EARS for measuring a safe SPL

[luizffgarcia]

Hey guys, i got the EARS today and i would like to use it to measure my volumes as well as frequency response.

I have configured REW using the L and R calibration files and when i open the SPL monitor my room is at a constant 60dB which i find strange since it is not noisy, and the volumes i am used to listen to are above 85dB!!!

I see there are a few configurations at play but i don't know where to start, there are A / C / Z weights for example, lots of volumes and gains to change everywhere. I could really use some help figuring out if i am doing this right

 

[John Mulcahy]

What is the serial number of the EARS unit and what version of REW are you using, on which OS?

 

[luizffgarcia]

What is the serial number of the EARS unit and what version of REW are you using, on which OS?

Thanks for the quick reply!

The serial number is 860 2992, i have the gain switches set to up / down/ down / down.
The software version is 5.20.9, running on Windows 10. All windows levels are set to 100%.

 

[luizffgarcia]

Some screenshots:

 

[John Mulcahy]

Load the cal files in the mic cal files entry that is highlighted in purple, that is the one being used.

 

[luizffgarcia]

Load the cal files in the mic cal files entry that is highlighted in purple, that is the one being used.

It was already loaded.

 

[luizffgarcia]

Does the windows microphone level play any role in this?

 

[John Mulcahy]

If you look at the levels slider on the Windows audio properties for the EARS you can right click on it to show the level in dB, ideally it should be at or close to 0 dB. You mentioned the gain switches, what gain do those settings correspond to?

 

[luizffgarcia]

If you look at the levels slider on the Windows audio properties for the EARS you can right click on it to show the level in dB, ideally it should be at or close to 0 dB. You mentioned the gain switches, what gain do those settings correspond to?

They correspond to 18dB.

You mean this slider?

 

[John Mulcahy]

No, the Advanced options, Levels tab, like the screenshot you posted of the Speakers properties.

 

[luizffgarcia]

No, the Advanced options, Levels tab, like the screenshot you posted of the Speakers properties.

This one?

 

[John Mulcahy]

Yes, right click on it and select decibels instead of percentage.

 

[luizffgarcia]

Yes, right click on it and select decibels instead of percentage.

Then it shows 0dB

Does this all mean i got all settings set correctly? I am very surprised my room is at 66dB at all times and the volume i am used to listening to music is showing 88dB. I was really hoping something was wrong with the setup that could cause these high numbers

 

[John Mulcahy]

They look right, but 66 dB as a background level is very unlikely. You could use the RTA to see if there's something that might explain that.

 

[luizffgarcia]

They look right, but 66 dB as a background level is very unlikely. You could use the RTA to see if there's something that might explain that.

Sorry i am new to all of this, how would i do that?

 

[John Mulcahy]

RTA button, then open the controls (cog icon top right) and configure like this:

Press the record button in the top right corner of the graph to start the capture and see the frequency content of what the EARS is picking up, perhaps there is some strong low frequency signal.

 

[luizffgarcia]

RTA button, then open the controls (cog icon top right) and configure like this:

View attachment 53436

Press the record button in the top right corner of the graph to start the capture and see the frequency content of what the EARS is picking up, perhaps there is some strong low frequency signal.

I have managed to lower the ambience noise by turning off the AC and lowering the PC fan speed.

There is something at 40hz still going to 54dB, but i think 54dB is expected for a quiet room, right?

 

[John Mulcahy]

A little high perhaps, but the 40 Hz source looks to be the main contributor - the A weighted level is only 43.9 dB which is quiet.. You can see more of the graph by either scrolling down a bit using the scroll bar at the left or setting a lower level for the bottom of the graph using the limits button, which is next to the controls cog.