Mar 09, 2010

Ethan Winer's Audio Myths Workshop from AES NYC 2009. I haven't had a chance to watch the whole thing, but what little I have seen is great stuff.

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Mar 05, 2010

The calibrated microphones that I sell each come with a CD that includes the frequency response files for each individual microphone. The file format is a space-delimited text file with a frequency [Hz] , level [dB], and phase [degrees] triplet on each line as follows:

5 -14.04 0
6.3 -9.90 0
8 -6.933 0
10 -4.732 0
12.5 -3.16 0
16 -2.06 0
[...]


(Slight digression about microphone phase: I add a value of "0" for phase for compatibility with the file format, but I don't actually measure microphone phase - in fact there's really not a good way to measure absolute microphone phase, but that's another blog entry.)

This text-based file format is understood by most any PC & Mac-based acoustic measurement package that I've come across (SMAART being the notable exception). But customers do tend to come across one compatibility problem: I chose to use the Frequency Response Data (.FRD) extension because it is a documented format. The problem is that although many software packages can handle the file format itself, they don't like the ".FRD" extension - instead many of those programs use a variety of extensions such as ".txt", ".mic", ".cal" and others. The problem can be resolved by changing the ".FRD" extension to something that the program recognizes and usually everything will be fine, but this has been confusing for people. Despite the inclusion of a "Read Me" file on the discs that include this explanation, I spend a lot of time taking phone calls and responding to emails to help customers with this problem.

I really don't want to go down the road of including files with every possible extension under the sun as that's sure to be more troublesome then it's worth. Given that most acoustic software packages can handle the basic format, I think it would really be better for the industry as a whole if we would just settle on a common format for calibration data.

To that end, I've reached out to the authors of serveral popular packages to see if we can agree on a common file extensions for calibration data. As of now, REW, Speaker Workshop, and SoundEasy currently support ".FRD". The authors of True RTA and ARTA inform me that their next versions will include support for the ".FRD" extension. I have unfortunately not heard back from the authors of FuzzMeasure, WinMLS or Aurora. But I am hopeful we can move foward on standardizing on a file extension for calibration data. It's a small thing, but it's the type of thing that has tripped people up and we need to get on the same page.

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Mar 04, 2010

Two AV podcast-related items of note :

• The HT Guys are celebrating their fifth anniversary by giving away prizes to listeners. One of the prizes they are offering is a microphone by yours truly. To enter the drawing, you just have to subscribe to Ara's and Braden's Twitter feeds and they will select winners from their followers later this month.
  
  
• Tom at AVRant again mentioned using generic calibration files for Behringer ECM8000 (and similar) microphones. I sent him an email about this topic; in his response, Tom mentioned that he's always on the lookout for free samples. In an attempt to buy his love, I sent him a Premium+ microphone. He's been gentle so far, hopefully I won't stir his anger. BTW Dina, the 'H' is not silent :).

The HT Guys and AVRant podcasts are two of my favorite podcasts and I'm grateful for the mentions on these shows.

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The Boston Globe ran a story about a death at Massachusetts General Hospital which was traced to a heat monitor alarm that was switched off. An investigation showed that medical equipment alarms could often not be heard by hospital staff. The proposed solution: "[turn] up the volume on all the alarms, [install] new speakers, and [assess] whether these changes solve the problem."

Dr. Solet of Harvard Medical School wrote a letter in response to the article:

As a sleep researcher who has been studying noise in health care facilities, I would urge hospital decision makers and health technology innovators to find a better solution to hospital alarm errors than turning up the volume on all the alarms. When alarms are not heard, a better solution may be to lower the background noise levels.

Don't raise the volume of the alarms, reduce the background noise level. Makes perfect sense and I'm glad Dr. Solet spoke up.

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Feb 07, 2010

Did everyone notice that Baylen Brees was fitted with a set of Peltor hearing protectors during the Super Bowl XLIV trophy award ceremony? I'm pretty sure they were the Peltor H7A Over-the-Head Earmuff.

Best Father Ever.

Update, Feb 8, 2010:

Consumer Reports offers its kudos.

Update, Feb 9, 2010:

In an interview in Inc. Magazine, a Peltor executive says that the hearing protectors are Peltor Junior Earmuffs

Update, Mar 3, 2010:

The New York Times gets in on the action:

The boy was wearing what looked like the headphones worn by his fatherÕs coaches on the sideline, but they were actually low-cost, low-tech earmuffs meant to protect his hearing from the stadiumÕs roar.

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