When listening to Electro Swing songs such as Booty Swing by Parov Stelar , I am encountered with the familiar "old voice" in most swing songs that feature a woman singing, but the voice is low quality and the music is full of white noise. I was just wondering how they could get this noise with all the modern-day recording equipment? Where do they find the 1920's type microphones? Or did they just transform the recording using some sort of application like Audacity?
A lot of what we think of as "old time" vocals was due to the very limited frequency response of the old microphones that were used at that time. The same thing applies to telephone audio in the pre-digital era.
A few minutes of experimentation with a parametric equaliser and you can easily find the band of frequency response that sounds authentic as an "old time" microphone or a telephone.
In this particular case, and for many electro-swing songs, the voice is actually a sample of a genuinely vintage song:
This is Lil Hardin Armstrong, Louis Armstrong's second wife, singing "The Oriental Swing." (Part of the tip-off that this is an actual old song are the non-PC lyrics)
However, there are many people who do recreate vintage vocals --it can be any combination of vocal style, vintage recording equipment and applied effects, such as static.