# Fletcher�Munson curves



## Chucka (Feb 17, 2014)

*Fletcher–Munson curves*

Which receivers and processors have the ability to insert some tye of automatic Fletcher–Munson curve into their signal path?


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## Babak (Mar 20, 2009)

*Re: Fletcher–Munson curves*



Chucka said:


> Which receivers and processors have the ability to insert some tye of Fletcher–Munson curve into their signal path?


Any amp or receiver with a ' loudness ' function. 

You can also use any device with bass and treble controls. 
That would be the better solution because the Fletcher Munson curves represent average values. 
Your individual curve will most probably be different. 

You should also be careful how strong the correction is at which listening volume. 

Sound engineers mostly calibrate their systrms at 85 dB (A) with pink noise, and to 96 dB (A) peak. 

So if you listen with a volume setting that gives you 85 dB (A) with pink noise, you don't need to correct for Fletcher Munson - a flat setting is right. 

The lower your listening volume, the more you need to increase bass and treble (more for thebass than for the trebles) 

Cheers 
Babak


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## BeeMan458 (Nov 25, 2012)

*Re: Fletcher–Munson curves*

My understanding, any AVR with Audyssey and Dynamic EQ.


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## Chucka (Feb 17, 2014)

*Re: Fletcher–Munson curves*



BeeMan458 said:


> My understanding, any AVR with Audyssey and Dynamic EQ.


Yes - But how about on non-Audyssey models and what do these manufacturers call this feature on their models. I consider this an important feature and use it on on my Lexicon DC-1 but this will soon need to be replaced. I am not a fan of Audyssey as I want to have some level of manual adjustment. Right now I am leaning towards Pioneer models but not until they update MCACC to includ subs.


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## primetimeguy (Jun 3, 2006)

*Re: Fletcher–Munson curves*

THX receivers with THX Loudness Plus.


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## BeeMan458 (Nov 25, 2012)

*Re: Fletcher–Munson curves*



Chucka said:


> Yes - But how about on non-Audyssey models and what do these manufacturers call this feature on their models. I consider this an important feature and use it on on my Lexicon DC-1 but this will soon need to be replaced. I am not a fan of Audyssey as I want to have some level of manual adjustment.


With many of the upper end AVRs, they come equipped with XT32/SubEQ HT for subwoofers. In our case, we have separate PEQ that allows for the control of a trouble frequency, dip or peak, which has a width of filter potentiometer and gain control for the filter on each of the two subwoofers. On the backs of the Rythmik subs are several additional adjustments besides phase, gain and LPF. In the main menu of the AVR we have individual levels, crossover and speaker size to handle bass management issues.

What kind of manual adjustment are you wanting? Maybe the purchase of a yet to be released Emotiva XMC-1 and one or two of their separate amplifiers?

*Features

Audio Capabilities
Exclusive Dirac Live™ 7.2 automatic room correction system with PC/MAC GUI for complete system control and adjustment, "on-the-fly,” including the creation of your own customized response curve for precise alignment with your individual preferences.*


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## Chucka (Feb 17, 2014)

*Re: Fletcher–Munson curves*

"What kind of manual adjustment are you wanting? Maybe the purchase of a yet to be released Emotiva XMC-1 and one or two of their separate amplifiers?"

After level calibration, this feature should only be in the form of an ON/OFF Switch. The Emotiva XMC-1 has this option spelled out in its specifications but eveyone has been waiting for the release of this unit. WHEN released, it may be an option but "Wife Factor" may require a single box (Pre and Amp) solution.

It looks like "THX Loudness Plus" menioned above may be this same feature that I am lookg for, so it opens up the options as to what I can select for a receiver.


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## lcaillo (May 2, 2006)

*Re: Fletcher–Munson curves*

Years ago Yamaha had variable loudness contour on all of its receivers and some other components. The control was based on the principle behind the F-M curves and as you turned it up provided more attenuation of the midrange relative to the bass and treble. I know of no similar manual adjustment today.


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## nathan_h (Feb 19, 2009)

*Fletcher–Munson curves*

Interesting thread. Two years later and the marketplace is still bereft of options -- other than Audyssey and their Dynamic EQ, which is not too bad, assuming you want to use Audyssey.

And that's the catch. I sort of don't want to use Audyssey. I prefer a less aggressive room correction system, such as whats possible via the PEQ function of a MiniDSP or even the PEQ in a Yamaha. 

But Audyssey won't let one use Dynamic EQ without using Audyssey itself. So my compromise may be to use MiniDSP before running Audyssey, and leaving it on and in line, before the amp -- in the hope that Audyssey will see a pretty flat response and do very little modification of the signal.

And then I'll choose the "Bypass L/R" type of Audyssey curve. Depending on who you believe or what you read, this either doesn't touch the L/R speakers AND treats them as the "correct curve" and applies that curve to the other speakers. Or Bypass just ignores the LR AND does normal Audyssey stuff to all the other speakers (seems unlikely).

Not ideal, but it is what it is.


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## robbo266317 (Sep 22, 2008)

*Re: Fletcher–Munson curves*

The difficulty lies in the size of the room, speakers, and the listeners expectations.
You cannot factor in every users requirements, so they "average" the results to try to please everyone. :huh:


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## nathan_h (Feb 19, 2009)

*Re: Fletcher–Munson curves*



robbo266317 said:


> The difficulty lies in the size of the room, speakers, and the listeners expectations.
> You cannot factor in every users requirements, so they "average" the results to try to please everyone. :huh:


I think that is reasonable (though it would be nice if the user could tweak the "average").

But my "complaint" is that other than Audyssey enabled AVR's, no one is even using or attempting an imperfect average. They are just punting on the idea entirely, which is ashame. 

I'd speculate that this is why many people manually goose up their subs and surrounds. It would have been fine to listen to a relatively flat response, at reference volume, but even people that like it loud seldom listen at reference -- so to perceptually achieve reference level like balance they have to manually goose up the sub and surrounds.

Would love to see the market respond with something more scientific than that method


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