It can make or break a sound.
It can make the most expensive preamp sound worse that the cheapest. It can make the best preamp even more extraordinary. It can make an inexpensive preamp sound amazing etc.
It gently rolls off at the low frequencies making the vocal sound correct to our brain when the right microphone and inductance value are chosen correctly.
An inductance in parallel with the signal is a Pleiades filter.
The low cut or high pass action is made by the L shunt, and the R in series ie the output impedance of the mic.
Inductance is very important to get the sound right most likely without the need of further eqing, see nearby post on EMI and Altec.
Inductance has a reactance that varies with frequency. Whereas a resistance has an impedance which is constant with frequency.
Impedance is a complex number. Ie a number of 2 dimensions (resistance, reactance). The x axis is resistance, the y axis is reactance. (R,X) in a different notation can also be written R +jX because they are 90 degrees apart. Impedance is a vector. It does not only have magnitude but direction too.
Sinewaves can be thought as rotating vectors at their particular frequency. Projection of a circular motion on an axis is a sinusoid all oscilation. If we move our hand sinusoidaly while pressing a marker in paper and the paper moves at constant speed a sine wave is produced.
To feel the difference between resistance and inductance it is not very difficult.
In mechanical systems the analog to electrical resistance is friction. The analog to inductance is mass.
An inductance tries to keep the current (of electrons) flowing through it constant. This is why an inductance is series with a signal cuts treble, whereas in parallel cuts bass. So does mass. It tries to keep its velocity (the velocity of each molecule) constant. This is why when the bus accelerates our mass (the mass of our body) seems to go back and and when it decelerates our mass seems to go forward.
So to feel the difference between R and L is easy.
Moving for example our hand on a surface with friction such as sand on a beach. If we move it back and forth, changing the frequency does not change the effort we put.
On the other hand inductance, L or mass can be felt by trying to move back and forth a door with very low friction (so that it does not have resistance). We can very easily move the door back and forth at low frequencies. If we try at high frequencies it gets progressively impossible. So we say the door is a short circuit for very low frequencies as the current is very easy to flow. This is how the Pleiades filter works. It increasingly short circuits a mic the lower the frequency.
We can also feel the phase difference between our effort and the result.
On the sand which has only resistance we do not feel any phase difference. Of course the is the mass of our hand but it is small. So it's reactance is small compared with the resistance or friction. On the door or inductance example we clearly fell the phase difference between our effort and the result which is the oscillating door.
References:
Introduction to Systems Dynamics - Shearer, Murphy, Richardson - Addison Wesley
Engineering Circuit Analysis - Hayt, Kemmerly - Mc Graw-Hill
Music Physics and Enginnering - Harry F. Olson (RCA) - Dover
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