loudness control

Status
Not open for further replies.
Jump to Latest
#3
The loudness function is most often tied into the volume control via a separate tap.

There are drawbacks to this scheme though as it cannot take into account the amplifier or speaker's sensitivity. If you familiarize yourself with the operation of loudness circuitry you might find a workaround.

Try googling for - loudness control circuit - or something similar.
 
#5
Yes, the tone controls on many pre-amps would work fine but what a pain in the butt to use.

A good loudness circuit tailored to the amp/speaker sensitivity would be ideal. Better yet, there could be a sensitivity adjustment to make it universal.

A good DIY project!
 
#6
Probabaly the most useful contibution in this field is to be found in an old copy of "The Journal of the Audio Engineering Society" (JAES). It is a four page article that describes a "loudness control" built around an inverting op-amp with seven passive components and a linear potentiometer. The authors tackle the problems in this area by having both a fixed and a variable breakpoint to the time constants in the bass region and come up with a circuit that follows the Fletcher-Munson contours to within 3db over a 40db range. The full reference is; "Practical Loudness: An active circuit design approach." Arthur L. Newcomb and Richard N. Young. JAES Jan/Feb 1976 Volume 24, No.1. It is easy to miss the article as it wasn't large enough to go in as a feature and you will find it hidden away in the section called "Project Notes/Engineering Briefs". Many of the bigger City/Uni libraries hold large sets of the JAES but if you can't reach one of these The Societie's reprint service is very efficient. Unfortunately I haven't got their their contact details. They're in New York I believe. Another member may be able to post the details. Jonathan Bright.
 
#7
Loudness

This variable loudness is not a traditional loudness since the Loudness effect does not vary with volume setting control.

The pre-amp circuit includes a gain 5.7 without the loudness. When the switch is in OFF position, the pre-amp still give low sub-audio frequency a pre-emphasis allowing the phase shift at 10 Hz to be lower than 0.5 deg, thus the 10 Hz square wave is almost perfect.

I am very pleased with the result. If anyone has tried something similar or would like to comment...
 

Attachments

  • pre-amp_loudness_1.gif
    pre-amp_loudness_1.gif
    10 KB · Views: 3,735
#10
if you want something w/o adding any active circuit in series in your existing system, use the circuit in post #7 where the loudness is included in your actual pre-amp (in the feedback path of your pre-amp, provided that is is a non-inverting one). You simply have to modify your pre-amp but ensure to put the potentiometer close to the pre-amo circuit to prevent capturing too much noise, thus locate the pre-amp circuit close to your pre-amp front panel where the pot is located...
 
#12
#14
Activ filter for loudness (50Hz and 15kHz)

fab said:
This variable loudness is not a traditional loudness since the Loudness effect does not vary with volume setting control.

The pre-amp circuit includes a gain 5.7 without the loudness. When the switch is in OFF position, the pre-amp still give low sub-audio frequency a pre-emphasis allowing the phase shift at 10 Hz to be lower than 0.5 deg, thus the 10 Hz square wave is almost perfect.

I am very pleased with the result. If anyone has tried something similar or would like to comment...
Click to expand...
Hi fab!
Is can offer circuit or schematics with an active filter that will be able to make the 15...16kHz gain of about 10dB at about 50...60Hz as reinforcements for about 10 dB, 1 kHz at a gain of 0dB.
Thank you and cheers!:cheers:
 
#15
Oh , it's very easy
Just substitute the actual tweeters with ones having more sensibility ( and SPL !!!! ) ;maybe the crossover has to be redone ; putting an L-pad you can
vary from normal to +10 dB , and maybe a compression driver is required !
For the bass region , no problem again : multiple subs ; those can be driven
by just a mono amp ; 3 or 4 would already give a 10 dB boost at 50 Hz
😛😛😛
 
#16
picowallspeaker said:
Oh , it's very easy
Just substitute the actual tweeters with ones having more sensibility ( and SPL !!!! ) ;maybe the crossover has to be redone ; putting an L-pad you can
vary from normal to +10 dB , and maybe a compression driver is required !
For the bass region , no problem again : multiple subs ; those can be driven
by just a mono amp ; 3 or 4 would already give a 10 dB boost at 50 Hz
😛😛😛
Click to expand...
Hi picowallspeaker!
I need electronic circuit for loudness in the pre-amp with the above characteristics.😡
thank you!
 
Status
Not open for further replies.
Top Bottom