Vaya vaya con los logaritmos!!
Me paso exactamente lo mismo que al del otro hilo!!
Me puse a conectarlo todo a la noche y cuando acabe eran las 11 y pico. A esa hora no podía probar mas volumen y cuando vi que estaba a 3/4 de potencia pensé que poco mas podía quedar. Y la impaciencia me llevo a hacer mil pruebas: entradas, conexiones, otros altavoces, pero sin subir de -20dB.

Probare hoy a horas mas decentes y a ver si la cosa mejora acercándome a 0dB.

Buscando buscando me encontré también con un concepto distinto al que explicáis en el otro hilo: ni potencia total ni voltaje de entrada. Parece bastante extendido el tema del “reference volume”. Por ejemplo aquí:

What do the numbers mean on volume displays (when volume is show in dB) ?
Many AVRs show volume in dB rather than a scale such as 0 to 100. Some people wonder why this is, especially why number go negative.

dB is short for decibel. A decibel measures the difference between a quantity and a reference value. Unlike a unit like volts or watts, dB has no direct physical meaning. It's dependent on what quantities are measured.
There are different kinds of dB. For example, sound pressure (SPL) is also measured in dB. There is a correlation between SPL and your volume readout due to the fact that they both use dB. And I will explain that in a moment.

Before we go further, the reason volume is often negative is due to how logarithms work. As the formula for dB uses logarithms, a value less than reference will be negative. When our current volume is less than the reference volume, it will be negative.

As different receivers can use different values for their reference volume, let's choose one for discussion purposes. THX came up with a concept called THX reference level. A receiver calibrated to THX reference level will play back movies at an average of 85 dB SPL when their volume is set to 0 dB. For this discussion, we will assume this is how all receivers work (they don't, just to be clear.)

Any volume which produces an SPL less than this average level of 85 dB, will be negative, because that's the way dB works as mentioned above. A volume 0 dB would produce an SPL of 85 dB. A volume over 0 dB will be greater than the reference volume.

Because 0 dB volume on our receiver puts out 85 dB SPL, we expect -10 dB on our receiver to put out 75 dB. This works on my receiver, anyway, and hopefully works on most receivers. For a volume of -20 dB, we would expect an SPL of 65 dB.

An SPL increase of 10 dB is approximately twice as loud to human hearing. An SPL decrease of 10 dB would be half as loud. A 3 dB change is just noticeable. Some people may be able to hear smaller changes.

No tengo mucha idea del tema e igual estoy mezclando churras con merinas…

Muchas gracias por la ayuda

Un saludo