Out of curiosity, can someone explain to me exactly what it is that loudness does? Is it an equalizer? A compressor? Both? Neither?

/Pepijn

To my knowledge, it boosts bass at low volume levels, gradually reducing the boost as volume increases.

There is apparently a curve of which frequencies it boosts and when but nobody has ever published it AFAIK.

Someone must know the exact details. After all, they implemented it. Empeg guys?

/Pepijn

I think that is an internal function of the DSP IC. Tony has the datasheet but it is not listed in there apparently.

Probably only some Philips people will know.

The dynamic loudness feature is a hard-coded DSP feature. The data sheet refers to it, but the characteristics of the algorithm doing bass boost is defined in the programming and applications reference manual. This is available only under NDA, which the Empeg team has. I don't think they are prevented from revealing the characteristics, since the DSP is designed to be an operational output stage to commercial audio products, and as such, it's characteristics should be quotable as performance characteristics of the product it is in.

The best solution is to ring up the Wrestler's Arms, their local pub, and give your credit card details to the landlord. Buy the team a round of beer, and I am sure that they will then specify the loudness characteristics for you

To my knowledge, it boosts bass at low volume levels, gradually reducing the boost as volume increases.

That is correct. Its purpose is to compensate for the perceived non-linearity of the frequency response of an audio signal. As you turn up the volume, the bass seems to get louder more quickly than the treble does.

There is apparently a curve of which frequencies it boosts and when but nobody has ever published it AFAIK.

The empeg guys just implemented whatever the DSP programming manual recommended. They took it a step further than most car stereos do, by making it a scale instead of just on/off.

I would like to have another parameter in addition to the scale: The upper cutoff volume. As it stands right now, there's still a little bass boost even at maximum volume. I would like to adjust that point downwards so that there is zero bass boost at about -7db. How about it empgeg guys?