As file resolution goes up sound level goes down?

I have noticed this too. I think it is because these files use much greater dynamic range. They are not as compressed as standard redbook files or CDs that you are used to listening too, where the overall level is mastered higher and closer to clipping (0 db) output. Perhaps someone with more technical or professional recording background can fill us in more?

This is profound in my system because my speakers are low impedance (2.5 to 4ohms) and insensitive (86db), plus I use a tube amp. I'm just fine with my analog front end, but I'm running out of headroom with digital.

Maybe get a DAC with adjustable gain or higher output? Or, a pre with more gain? Or, would a step up transformer help increase output between your DAC and pre? My Bel Canto DAC3 puts out 4.5 v via XLR, so I get plenty of gain no matter the source.

Thanks Swanny, but my next major upgrade is to replace my seventeen year old Thiel speakers with much more sensitive ones. That will also fix the problem.

I suspect that Swanny's diagnosis is correct. Material that is not as dynamically compressed will have a lower average volume, assuming that peak volume is similar.

You can confirm that by using an audio editing program, such as the free program Audacity, to examine and analyze the sound waveforms of the respective files.

I suspect that what is limiting the dynamic range that can be handled by your system is the combination of a relatively low powered amp and inefficient speakers. If so, increasing the gains, sensitivities, or output levels of upstream components will not help, but changing to more efficient speakers would, of course.

Also, it appears that the 86 db sensitivity of your speakers is specified with respect to 2.83 volts, rather than 1 watt. 2.83 volts corresponds to 1 watt into 8 ohms, but to 2 watts into 4 ohms. Given the speaker's 4 ohm nominal impedance, its efficiency is therefore only 83 db for a 1 watt input, at a 1 meter distance.

Regards,
-- Al