Loudness versus Volume

[Guest]

Question: I'm screwing around with my Magni3's gain switch while listening to Songs Of The Auvergne (featuring Dawn Upshaw & Kent Nagano).  I flick the gain to "low", I can rotate the pot clockwise and make it louder (it seems easier to fine tune). I switch it to "hi", I just nudge the pot to make it loud enough... but here's the thing, I'm perceiving more detail.  Is this just my audio nervosa playing tricks on me or have I just re-discovered an aural phenomena -- volume versus loudness? I went to Encyclopedia Britannica... and it started chattering about "phon" units (huh?!).

 

Other than going back to university to learn audio theory, is there a resource that "those in the know" use... either online or as a book?  This is my signal path: PC >> ModiMB >> SYS (<< Satellit 750 multiband radio) >> Loki >> Magni3 >> (MDR7510 + HD6XX) >> aural pickups w/ tinnitus ( = St. Lawrence Seaway SCUBA) >> CNS 

[Volbet]

Well, phon units are only used to quantize perceived loudness of a steady tone (with 1KHz being the standard). It's simply a way to normalize perceived volume without relaying purely on dB SPL.

Since human hearing a fickle bitch, that perceive different tones differently, then the phon units do become useful.

If you've ever taken a hearing test you've more than likely been subjected to tones that have been equalized via a phon curve.

 

So, this has no relation to what's happening within your headphone amp.

What's going on there can be anything from placebo to a change in how the circuitry in the amp handles the increased output.

[EsaT]

Unless having something to measure and match volume, it would be easy to go to higher volume with high gain giving faster ramp up of volume.

And higher SPL makes human ear more sensitive to treble in comparison to mids.

[Guest]

2 hours ago, Volbet said:

Well, phon units are only used to quantize perceived loudness of a steady tone (with 1KHz being the standard). It's simply a way to normalize perceived volume without relaying purely on dB SPL.

Since human hearing a fickle bitch, that perceive different tones differently, then the phon units do become useful.

If you've ever taken a hearing test you've more than likely been subjected to tones that have been equalized via a phon curve.

 

So, this has no relation to what's happening within your headphone amp.

What's going on there can be anything from placebo to a change in how the circuitry in the amp handles the increased output.

Yep, my hearing's indeed a fickle bitch (love the imagery). Your thoughts about the switch are welcomed, eh. So, phon units are used to describe steady tones, eh. Good to know. Thanks @Volbet

1 hour ago, EsaT said:

Unless having something to measure and match volume, it would be easy to go to higher volume with high gain giving faster ramp up of volume.

And higher SPL makes human ear more sensitive to treble in comparison to mids.

@EsaT ... SPL... you're referring to sound pressure level, right?