The AT4081 is the less-expensive of of a pair of new phantom-powered ribbon microphones from Audio-Technica.
Introduced in 2009, the AT4080 and AT4081 feature several new ribbon-motor developments. Audio-Technica claims to have 18 patents pending for these new mics.
The motor is a dual-ribbon design. The use of two ribbons can increase the sensitivity of the transducer, as they are wired in series. The two ribbons are mounted front-to-back, with one slightly in front of the magnetic pole and one slightly behind it.
As in all modern ribbon mics, the magnets are Neodymium.
This patent application’s claim appears to be limited to the idea that by corrugating the ends of the ribbon such that the lines are parallel to its length, the ribbon is stiffer and therefore easier to install, and further that the clamping mechanism can form a tighter electrical connection to a surface with “a plurality of stripe-like irregularities,” reducing resistance.
The application also mentions the use of a slightly-U-shaped ribbon clamp, which when tightened flattens out to better grip the end of the ribbon.
The ribbon is connected to a transformer, which in turn feeds an amplifier circuit fed by +48V phantom power. The amp’s self-noise rating, 25dBA, is fully 3dB noisier than the AT4080. It is the noisiest active ribbon mic we’ve seen.
The output circuit is transformerless.
The AT4081’s frequency response is flatter in both the lows and highs than is the AT4080. -3dB points are 40hZ and ~16kHz.
The AT4081 ships with an “isolation clamp” (aka mic clip), a soft pouch, and a padded storage case.
How do the AT4080 and AT4081 differ?
The AT4081 list price is $400 lower.
The AT4081 has a smaller transformer, and 3dB higher self-noise than the AT4080.
The case and headbasket design are different; the AT4081 is physically smaller, making it easier to position for instrumental applications.
The low-frequency response of the AT4081 rolls off below 60Hz, whereas the AT4080 has a low-frequency boost suitable for vocal applications.
The AT4081 won a Reader’s Choice award from ProSoundWeb in 2010.
Prior to this, I had never gotten good results using ribbon mics as [drum] overheads. [Yet] the extended high end, accurate midrange, and lack of muddiness of the 4081 is just perfect for drum recording.