What is "Loudness effect"?

What is “Loudness effect”? I see it at “Equal-loudness contours”.

Where you you see this?

Could it be that your player is set to a non-English mode and that this is SanDisk’s feeble attempt at language translation? That this is what it ‘says’ (translating to english) on your player? It might mean Equalizer. 5 bands ranging from bass to treble where you can add or subtract emphasis on these frequencies.

Human ears are much more sensitive to sounds in certain frequencies than others. They are most sensitive to the frequencies of a baby crying and female voices. Those frequencies can be heard at much lower decibal levels than other frequencies. Equal loudness curves are measured in phons, and show this effect. A sound needs to be at least something like 70 db at 20 hz to be just barely audible, while at 3 khz a very low volume sound is still audible.

For example, a sound at 10 db at 1,000 hz sounds as loud as a sound of around 30 db at 100 hz. Both are at 10 phons. Notice that with higher volumes the curves flatten out. A sound of 50 db at 1,000 hz sounds as loud as a sound of 60 db at 100 hz.


Message Edited by JK98 on 09-06-2009 02:22 AM

JK98 - Excellent explanation!!! This contour stuff reminds me of how so-called audiophiles want a flat response curve on everything to recreate the source sound as accurate as possible. And what is their DAP of choice? The Cowon D2, which has a modified response curve that is far from flat. So if they go by their own rules, they should be listening to the current Sansas which are dead flat. Cowon raised the high and low end and dipped the mids slightly. The result, a very balanced sounding player because it helps makes up for human hearing deficiencies with its response contour.

Theoretically having a loudness button on a stereo is legitimate, so that when music is listened to at a lower than normal volume, the music will sound the same(but quiter, with the lows and highs present in ample amounts so they are audible) as when it is played at a normal volume. The problem with such an adjustment though is that the player doesn’t know how efficient the headphones plugged in are, so it can’t know how a setting on the volume knob corresponds to the decidel level of the music. So therefore the player can’t know how much of this effect to use. Similarly, some players have volume limiter circuitry that may result in too little volume, since the player doesn’t know how efficient the headphones plugged in are, and what decibel levels the headphone is exposing the ear to. 

The whole idea of audio equipment though is to try to reproduce the sound of a live performance. Which reminds me of a question I have. With so much headphone listening going on now, why aren’t most recordings made in a binaural manner(with a dummy head with microphones in the ears). When done properly, this technique provides the best imaging for reproduction through headphones. Most recording today are made with the intention of being played back through speakers, even though the majority of listening hours are now probably done with headphones.

When recording are made to be played back through speakers, each ear  hears both channels(with the sound from the further speaker reduced a bit in volume and delayed a bit). Why don’t portable mp3 players have a crossfeed circuit that is adjustable in volume and time delay to provide this effect?

Message Edited by JK98 on 09-08-2009 01:56 AM