There’s a wealth of old microphones by well-respected brands, such as Sennheiser, Beyerdynamic or AKG, which are of limited use in the studio – we’ve already covered old omni microphones, but there’s another significant category: the classic announcement or public address microphones, built mainly for use in – as they were called in Germany – ELA (Elektroakustische Anlagen) systems.
They are optimized for speech intelligibility, most of the times they are not very musical and their frequency range is severely limited on both sides of the spectrum – there’s a high-pass filter or low-cut, to prevent handling noise, when the professor vigorously bends the gooseneck to utter her stance on queer thermodynamics and to prevent overall bass rumble. And often there’s some sort of high-cut, too, to avoid harsh sounding harmonics that are especially exaggerated when the sound is distributed on a PA system with cone speakers.
Many times, they also have built-in windscreens or pop killers to eliminate sibilance issues, wind noise and popping, which can seriously alter the sound and make them hard to use for any other purpose – especially since these pop killers were often made of foam, which by now has deteriorated to a slimy, filthy, gooey and incredibly gross mixture of tobacco-coloured spit and several potentially explosive chemical compounds. So, how do you recognize old public address mics and either avoid them, or grab them for their special sound?
If a microphone is available in a gooseneck version, that’s one hint already. If it’s only available as a gooseneck version, then that’s pretty much a dead giveaway. A gooseneck can be really neat to place your mic in hard-to-reach spots, such as under the snare or inside the second winding of a French horn, but many goosenecks have already had a long and painful life at the mercy of unskilled and impatient hands and are now tired of it all and let their heads hang – I’m unsure whether in shame or despair.
A dedicated table stand doesn’t have to mean anything, most mics in the 1960s and 1970s included one – but a fixed stand with a pushbutton has talkbalk pretty much written all over it. Even if the stand also says “Telefunken”.
Momentary pushbutton switch
Worse than a fixed stand with a pushbutton on it is a momentary on/off pushbutton switch directly on the body of the microphone. This feature is as “talkback” as it can get, and even though such a switch can easily be bypassed, it’s a rather obvious sign. You might even be looking at a microphone designed for radio amateurs – we haven’t explored that field very thoroughly, but besides the time-honoured tradition of spitting into the microphone through a harmonica, there might not be a lot you can do with it.
If you have access to some specs and find out that the microphone’s pickup frequency range really only starts at 100Hz or even higher, or if it has a severe rolloff in that frequency domain, then you can be pretty sure it was intended for speech only.
Talkback mics need to be small and efficient – no need to cram a Sennheiser MD421 into the crane operator’s booth when you can use an MD42 as well.
It’s definitely possible to find really good mics in talkback disguise as well. The above-mentioned MD421 can often be found mounted on a gooseneck, as well as several rather nice omnidirectional mics from Beyer or RFT / Funkberater – and sometimes really unlikely things happen, like a Beyer M81 which is mostly sold in a stereo combination with a second mic gets mounted on a stand equipped with a pushbutton…so don’t give up at the sight of a gooseneck!