 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
143.183.121.2
Has anyone built a Fletcher-Munson equalization circuit as a "tone control"?High efficiency full-range speakers with a large dynamic capabilty allow involved listenting at low average SPLs, but high SPLs are often pushed to substitute for bass compensation.
The Fletcher-Munson loudness curves indicate that low-level listening may not be as satisfying because perception of loudness is not linear, but is dependent on frequency and volume. The curves are flattest when the SPL is at the threshold of pain, so high SPL audio is often pushed to get satisfaction. Tone controls can rebalance sound to have the same pleasing amplitude spectrum at lower listening levels. The most accurate loudness compensation would dynamically adjust to both frequency and volume. Such dynamic filters are not widely available to consumers. Passive and active Fletcher-Munson loudness circuits are published on the web.
Follow Ups:
the f-m work was flawed because the impedance curves of the attenuators used were either measured incorrectly or marked wrong or something.this having to do with attenuated frequencies caused by the attenuators themselves.
and then another couple of people did the tests all over again with the correct impedance accounted for and came up with the revised measurements.
an acqaintance of mine who is an expert in cochlear studies also recounted a similar story when i asked him about f-m.
one of his papers titled --comparing octaves, frequency ranges, and cochlear-map curvature across species-- is on my desk.
he also sent me another paper by michele biasutti titled --sharp low- and high-frequency limits on musical chord recognition.
both of these were printed in the publication hearing research.
Very interesting topic. I have a triamped system with all-software crossovers. My crossovers provide driver equalization based on the frequency response of the drivers at (currently) about 100 frequencies for each driver. This really works well.I have been considering adding a layer of equalization to account for the Fletcher-Munson effect, but personalized for me by measuring my own subjective frequency response curves for at least a few loudness levels and generating another filter for each.
I use Octave's FIR2 function to generate the filters, and brutefir to do the convolution - it's a relatively straightforward process. This would make changing the volume fairly complicated, but automating it with a script would be pretty easy. The frequency response curves are also not too difficult to generate, but a bit tedious.
I don't understand. Even if our perception of loudness changes with volume, this is what happens in nature. Anything else may sound unnatural (and I certainly don't see a need for it).
I would appreciate any listening impressions from high efficiency full range speakers that included SPL based equalization similar to the Fletcher-Munson curves. How well does F-M equalization work in the real world?Consider a 3-way crossed 80Hz, 3200Hz. When you look at the F-M equalization curves for 60-70db SPL at 1Khz you see about 10db of boost is required over the 80-1KHz midrange. For our 80/3200Hz 3-way this would put 10db higher boost on the 80Hz bass-mid crossover than the 3,200 mid-tweet crossover. I wonder if this 10db boost at 80Hz would demand a steep sloped crossover to maintain a stable midrange sonic signature at different 1Khz SPLs.
I am also interested in finding the "best" active filter Fletcher-Munson equalization circuit as I am laying out a PCB for a 3-way active crossover and would like to include it.
I don't see how a Fletcher/Munson device can really work. It would depend on the level of the recording and only compensate for a given level. For every other level the control would be starting at the wrong point.
Hi Scooter,I have used this one before, however I omitted C4. Can't be loud all the time!
yamaha variable loudness control is cool too
Regards Philip
The Fletcher-Munsen is not a tone control...But is to be used as you turn the volume control DOWN. It compensates for losses in Bass end & some what in high frequencies but in a measured way. (normal compensation loss of the ear at softer levels) If you look at the curve you will see its variable shapes. "Your mother buys you books sends you to school but what do you do but eat the pages."
... and do the study yourself!The Yamaha curves were definitely based on Fletcher-Munson. I am pretty sure the EICO loudness contour was, too.
all the best,
mrh
Page 18 of this PDF, Fig. 13
all the best,
mrh
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
