For ultrasonic recordings an EQ up to 100 kHz is needed.
Anyone knows a good one?
I dont have any answer here. But curious what line of work you are in? Or is this for work or simply curiosity?
All of it.
- Physical measurements of combustion and other noise.
- On a private bases, I like to discover the ultrasonic world in everyday life.
Take a simple coin or key flip or just some droplets (just curious: does the spectrum depend on the viscosity of the liquid? - I guess, yes. And if so, how?) and record the sound up to 100 kHz. Then play it 10 times slower and listen to the phantastic sound that makes. We as humans have such a limited acoustic view of the world compared to other species, like bats, cats or dogs for example.
They can hear the whole orchestra of sound a simple key makes when falling to the ground - which does not sound as dull, as we perceive it.
Why the EQ?
I would like to correct some freqeuncies before shifting them down. The downshift is lossless by just playing at lower speeds. Then comes the noisefloor of the high frequencies of some microphones into play. I would love to hear the difference before timestretch.
For this, it is interesting to see the noisefloor of different microphones in the range above 20 kHz.
For instance, the Sennheiser MKH 8020 is quite silent up to 20 kHz, but than the noisefloor rises in the higher requencies. So, the noise distribution over the spectrum is very uneven. In contrast to an Earthworks M50 for instance. The later is noisier than the former overall, but the noisedistribution is very even over the whole spectrum. … just curious and such details are not seen in a simple number for the noise equivalent (A weighted).
With Spectral Layers, we have a great tool to work and see the whole spectrum.
So finally, yes, it’s a lot of curiosity with practical use.
A good EQ up to 100 kHz is hard to find.
Here a spectrogram of a falling key into a sink.
As can be seen clearly, the interesting frequencies are above 7 kHz up to 80 kHz. Might be even higher, but this is the limit of the recording equipment here.
