Help with Third Step on Audio Journey

[cdanielski]

The first step of my audio journey is still going strong; an entry-level 7.2 system purchased ~14 years ago:

• Polk Monitor 70 (L&R)
• Polk Monitor CS2 (center)
• Monoprice in-walls (surrounds)
• Acoustic Audio HDSub-12 (subs) X2
• Onkyo TX-SR606 AVR

It was great for family movie nights, but now that the kids are off to college, I took step two by learning to use REW with a Radio Shack Analog SPL Meter so that I could add a Behringer Feedback Destroyer (BFD) 1124P that was just collecting dust. That was something I had planned to do ten years ago but never took the time. Learning how to do all of that was extremely interesting, occasionally frustrating, and very rewarding.

Now I am eager to take my third step; purchase a calibrated microphone and dig deeper into REW so that I can maximize the audio experience as well as learn to build my own subwoofers. Which configuration would you start with and why?

• Cross-Spectrum Calibrated UMIK-1 > USB Cable > Macbook Pro (2013) or Acer Laptop (Win10).
• Cross-Spectrum Calibrated EMM-6 > XLR Cable > Focusrite Scarlet 2i2 (2nd gen) > USB > Macbook Pro (2013) or Acer Laptop (Win10).
• Other

Thanks in advance for your input!

 

[John Mulcahy]

Any of those would be fine.

UMIKs are individually calibrated at the factory, there isn't really any need to get them recalibrated at CSL. That is in principle also true of the EMM-6, but some of the EMM-6 cal data I have seen doesn't really look as it should, so CSL is probably a good option there.

Using an analog mic like the EMM-6 means you can use a loopback connection as a timing reference. You would need to enter a timing offset to remove the delay due to the time taken for sound to travel from speaker to mic.

Using a USB mic means using the acoustic timing reference which needs to come from a speaker that has a tweeter. That has the benefit of taking into account the time taken for the sound to travel from speaker to mic, so you don't need to manually remove that when looking at timing relative to whichever speaker you choose as the reference. It can get confused if there are very strong reflections in the sound from the reference speaker, however.

On Windows the Java drivers cannot access multichannel interfaces (like an HDMI connection to an AVR) and only provide 16-bit data. The 16-bit limitation isn't an issue for acoustic measurement, but the multichannel limitation might be. Both can be avoided by using an ASIO wrapper like FlexASIO or ASIO4All.

On macOS multichannel interfaces can be accessed directly and the data has the full resolution the interface supports. You need to make sure the interface format in Audio Midi Setup is configured for the sample rate you want to use in REW and for the number of channels you want to access.

 

[cdanielski]

Thank you, John. I appreciate your detailed explanation.