Dynamic Loudness and Headphones

[Jose Hidalgo]

Hi everybody,

As y'all know, Dynamic Loudness is about reproducing the Fletcher-Munson curves (or the more recent ISO 226:2003 curves that I'm not really convinced of as there may have been errors in the protocol - any thoughts BTW ?), so that when we change the Master Volume, the EQ varies accordingly.

In a speaker setup, this involves measuring the sound output at listening position with a dB-meter, and then calibrating your equipment accordingly.
For example you could measure sound output at 85 dB, then pick a pre-defined "85 dB" EQ setup, and you're good to go.
Some players like JRiver offer this kind of feature automatically (provided you still measure the sound output of course).

I was however wondering how we could achieve that in the case of headphones, since I don't know how to place a dB-meter in a pair of headphones to measure the sound output, lol.

Any ideas ?

 

[maverickronin]

I was however wondering how we could achieve that in the case of headphones, since I don't know how to place a dB-meter in a pair of headphones to measure the sound output, lol.

For this kind of purpose you can just sick your SPL meter right in the earcup and take a reading.

If you need the bass level to be accurate for another purpose just attach an old CD to the end of the SPL meter so you can make a seal with the pad.

 

[ernestcarl]

Hi everybody,

As y'all know, Dynamic Loudness is about reproducing the Fletcher-Munson curves (or the more recent ISO 226:2003 curves that I'm not really convinced of as there may have been errors in the protocol - any thoughts BTW ?), so that when we change the Master Volume, the EQ varies accordingly.

In a speaker setup, this involves measuring the sound output at listening position with a dB-meter, and then calibrating your equipment accordingly.
For example you could measure sound output at 85 dB, then pick a pre-defined "85 dB" EQ setup, and you're good to go.
Some players like JRiver offer this kind of feature automatically (provided you still measure the sound output of course).

I was however wondering how we could achieve that in the case of headphones, since I don't know how to place a dB-meter in a pair of headphones to measure the sound output, lol.

Any ideas ?

Ideally, you need to flatten the bass or get it close to flat as well as setting your DSP's 'relative' internal reference level -- let's say... to 80dB SPL with a -20dBFS narrow band pink noise signal (500-2kHz). Many headphones have a hump in the midbass or bass area. The bass boost, as you gradually lower the volume level, will sound over-excessive and boomy, otherwise. If you're already close to a flat baseline, just make minor adjustments to taste. As far as I'm aware, there is no 'perfect' Loudness/Dynamic equalization signal processor. The 'ISO 226:2003 curves' is based on an average -- it's not meant to represent your own hearing sensitivity to loudness at different frequencies at different SPLs 100% accurately.