Telephonics TDH-39P

This is one of the common audiometric headphone of the market.

The impedance is very low, only 10 Ohm compared with the 32 Ohm of the Bose so they are very powerful and easy to be driven by the iPad/iPhone with quite low calibration values.

There is also a 100 Ohm version that is a little too much for the iPad/iPhone especially at low frequencies.

You can buy used ones on eBay for 70$-100$

For Telephonics TDH series spec follow the link.
http://www.schaffrath.net/tdhspecs.pdf













Calibration values are the following:

frequency: 125  250 500  750 1000 1500 2000 3000 4000 6000 8000
values:     99   81  57   50   48   46   54   51   57   52   74   

New Version 3.2.0 is coming (September the 13)

I'm in "beta testing" of the last Audiogram Mobile version.

Here the new stuff:

Major Enhancements:

• New set of sound samples with 1db step instead of 5db
• New initial menu in order to accommodate more tests like "Speech Audiometry" and "PAR test" coming in next versions!
• Added note field to customer data in order to store medical information
• You can now swap the position of the charts
• You can now choose, add and edit customer data directly from the audiometric screen
• Graphic Improvements here and there
• IOS 7.1 supported
• Direct access to support web site
• Sennheiser HD-201 headphone pre-calibrated. The average cost of the headphone is 25$ / 20€

Bug fixing:

• Fixed an error that sometimes appeared when changing the frequency or volume
• Fixed a bug that prevent the birth date change

Release date: September, 13 

Some ScreenShots: