Wish Equal Loudness Contour in Global Settings

GotMetalBoy

GotMetalBoy

Power User
I think an Equal Loudness Contour setting in the Global Settings could be helpful when going from recorded tones to live tones or vice versa.

It could be modeled after the 6 curves in the ISO 226:2003 Acoustics - Normal equal-loudness-level contours standard. I manually adjust the Global EQ settings by lowering between 1.6K and 2.5K when I use recorded tones for live. Maybe there could be 12 presets that adjust the Global EQ, so there would be 6 positive values to use for higher SPL levels, 6 negative values for using at lower SPL levels and a default setting that makes no change. Maybe put an icon on the main display to let you know the Equal Loudness Contour is enabled and have a SPL- and SPL+ icon, so you'd know if you have it set for higher or lower SPL levels.

I know everyone's ears work differently but most people have experienced the huge difference tones change just from playing them at different SPL levels.
 
Playback systems don't have a linear frequency response either though, neither for amplitude or frequency. As a result, its going to take a different amount of cut/boost at a given frequency for one playback system that it is another.

My reference audiometer at work is calibrated for an equal loudness curve, so we can display thresholds of hearing level (HL) on a flat scale, but, its calibrated for the exact transducer I'm using with actual measurements.

Does a playback system have -3dB at 60 Hz or does it have -6dB at 60Hz, and how does that change based upon the output level ? Introduces a lot of factors that can potentially do more harm than good.

As I've said before, if you look at the curves of minimum human auditory perception in adults with "normal" hearing thresholds, the curves are essentially flat between around 100 Hz to 5000 Hz, at around 50 dB or so. Doesn't really change if you go to 80, 90 dB etc, and really around that range of frequency its still pretty darn flat even at softer levels. As a result, you can go from a soft late night level of 40 dB to 95 dB gig level and have a pretty accurate result still, at least within the range of guitar frequencies. Now yes, 30 Hz sub bass is going to be a totally different issue, as there is a huge fall off in human auditory perception that low, BUT, don't nearly all of us high and low pass our cab blocks around 100 Hz to around 5000 Hz, to better emulate a traditional guitar cab ? I know I do at least. As such, its kind of a moot point for most practical considerations.
 
lqdsnddist said:
Playback systems don't have a linear frequency response either though, neither for amplitude or frequency. As a result, its going to take a different amount of cut/boost at a given frequency for one playback system that it is another.

My reference audiometer at work is calibrated for an equal loudness curve, so we can display thresholds of hearing level (HL) on a flat scale, but, its calibrated for the exact transducer I'm using with actual measurements.

Does a playback system have -3dB at 60 Hz or does it have -6dB at 60Hz, and how does that change based upon the output level ? Introduces a lot of factors that can potentially do more harm than good.

As I've said before, if you look at the curves of minimum human auditory perception in adults with "normal" hearing thresholds, the curves are essentially flat between around 100 Hz to 5000 Hz, at around 50 dB or so. Doesn't really change if you go to 80, 90 dB etc, and really around that range of frequency its still pretty darn flat even at softer levels. As a result, you can go from a soft late night level of 40 dB to 95 dB gig level and have a pretty accurate result still, at least within the range of guitar frequencies. Now yes, 30 Hz sub bass is going to be a totally different issue, as there is a huge fall off in human auditory perception that low, BUT, don't nearly all of us high and low pass our cab blocks around 100 Hz to around 5000 Hz, to better emulate a traditional guitar cab ? I know I do at least. As such, its kind of a moot point for most practical considerations.
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I agree but the average guitarist would just tilt their head sideways like a confused dog if you tried to explain what you just wrote. I'm the kind of person that tries to figure out how things work, so I've read tons of stuff about how humans hear and it was very helpful. I've experimented with applying the inverse of the equal loudness curve to the low and high mids of the global eq for tones that sound harsh when played at loud levels and got pretty good results and none of the eq bands were lowered more than - 4dB. I think a lot of guitarists have no clue what frequencies affect what and change settings to their extremes. There's so many guitarist that I've seen turn up the bass and treble all the way and lower the mids all the way.

One question I have, do SS powered FRFR cabs change frequency response at different levels like the way tube amps do? I've never used a tube power amp with FRFR cabs.
 
chris said:
i don't understand; how would this situation be solved? the loudness thing?
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When I listen to music or mix, the SPL usually ranges from 60dB to 90dB. I've never tested the SPL level when I play in a band or with a drummer but it's probably close to 110dB and a lot louder playing through a full PA. I've noticed a lot of presets that sound good between 60dB to 90dB SPL sound very harsh when played at higher SPL levels. I've experimented with applying the inverse of the equal loudness contour qurves to the Global EQ and it made a noticeable difference and removed most of the harshness. My drummer also noticed a big difference. We both had less ear fatigue and the frequencies that usually cause our ears to ring seemed to be removed.

I think it would be very helpful to have a few simple EQ curves that could be applied to the Global EQ to remove the harshness caused by our non-flat ears.

I know it wouldn't be perfect but it would be similar to how the Amp Block has the Authentic switch. I think it would benefit new Axe-Fx users and musicians who have never recorded or done live sound.
 
The curves of audibility relate to very soft sounds, with the ear effectively pretty linear across the frequency range by 80 or so dB. It’s a potential issue mixing bass at 30dB and playing it at 70 dB, but there is no real issues going from 60 to 100+ dB as it’s already getting rather linear. 90 dB is a typical safe limit with about 96 dB being a permissible limit for a typical gig.

If your getting into 100+ dB your likely getting fatigue from damaging intensity levels, nothing to do with loudness contours. Your also likely getting harsh transients from the PA system and other non-linearities from driving the system hard. Even the best of Pa’s can sound harsh and ear fatiguing when pushed too hard.

I think your effectively just eq’ing your PA system to sound more listenable at high intensity levels, not creating equal loudness contours. It’s about the PA system, not your auditory system at those levels.
 
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