Industry Standard: the Sennheiser MKH-416
30th October 2015
Whether you know it or not, you’ll probably hear this microphone every day. With consistent use in TV, film and radio, it’s hard to avoid.
How has a microphone originally designed for tape recording nearly 30 years ago, managed to survive the digital format transition and still be so popular?
It is undoubtedly made to an incredibly high standard. If you own a 416, chances are you will never have to replace it. It might not be first choice boom mic for large productions, but there’s usually one or two as back up mics. Reliability is never going to be a worry.
A directional shotgun is always handy for a number of situations. Pair that with a forgiving frequency response for unwanted low end noise and the fact it’s an RF condenser microphone, makes it suitable for any location and humid weather. A handful of small design tweaks have been made over the years, (most notably lower self-noise and powering adaptations) helping the 416 comfortably slot into modern workflows.
A word on RF condensers: The RF system used in MKH Sennheiser microphones uses the capsule (a low impedance capsule) in a completely different way to AF capacitor microphones: as a tuning capacitor for an RF oscillator – which inherently employs it in a low impedance circuit where a high frequency signal is being passed through the capacitor all the time. Changes in capacitance alter the resonant frequency of the circuit and so its frequency becomes proportional to the audio signal. A simple RF demodulator restores the output to a conventional audio signal. It is a more complex and sophisticated system but still very rugged. This system is highly immune to the effects of humidity and is the preferred design to be used outside (or when moving from outside to inside on a cold day).
The 416 is often described as sounding “bright” or “tinny”, but what do these vague descriptions mean? And how do they influence our recordings today?
As the chart below shows, the response begins to drop off above 100Hz, considerably higher than modern microphones, which tend to start reducing around 60-80Hz. The lack of low end is what gives the microphone the aforementioned “bright” sound and effectively a built in roll off high pass filter near 100Hz. This makes field recording a little easier, as it’s less susceptible to unwanted noise at the bottom end of the audible frequency spectrum. This feature of the 416 also helps give clarity to dialogue, giving the less efficiently travelling high frequencies more room to breathe. These features have all been adopted by users over the last few years and were not necessarily planned characteristics of the microphone.
The reason the 416 has this response is because its initial development was for combatting the naturally heavy low end of tape during playback (known as ‘head bump’) and machine noise. What was initially a solution for flat sounding analogue recordings is now an accidental solution for recording dialogue in the field.
With a wave of new microphones from Sennheiser, came a direct replacement in the MKH60. Featuring a flat frequency response, on board roll off filter, high frequency boost and attenuation, it is undeniably a very good microphone and a theoretical improvement on the 416. Despite this, the MKH60 was not fully adopted by the industry.
Sennheiser themselves have not been able to phase out the 416, leaving it regarded as one of the best in class shotgun microphones today.