Audio loudness circuit.

[TerryG]

Does anyone know of a published schematic for an audio filter circuit based on the Fletcher/Munson loudness curve? I would especially like to know of a variable one like Yamaha used to use on their receivers.

Remember back in the day when had those loudness buttons on our stereos where we could compensate at lower volumes?

 

[JohnRoberts]

Its basically the inverse of the Fletcher-Munson sensitivity curve. Simply some bass and treble boost.

Back in the fancy old hifi receivers they would use a tap off the volume control to automatically reduce the amount of loudness boost above a level threshold on the volume control. This made the loudness compensation vary with volume pot control setting.

JR

 

[sahib]

Download National Instruments' Audio Radio Handbook from below link and check page 2.51

file:///C:/Users/Cemal/Downloads/6138.1980%20NSC%20Audio%20&%20Radio%20Handbook%20-%20Part%201%20(1).pdf

 

[gyraf]

Err in link, but very good reference.

perhaps try
http://bitsavers.trailing-edge.com/...aBooks/1980_National_Audio_Radio_Handbook.pdf

/Jakob E.

 

[sahib]

Apols. Should have paid more attention.

Thanks Jacob.

 

[TerryG]

Excellent information thank you gentlemen. I have a much older edition of that handbook lol, but it has all tube circuits.