Compared to the NAD HP50 and Paradox the HD650 IS 'bright' sounding.
Both the HP50 and Paradox drop off fast before 20kHz where the HD650 keeps going well over 30kHz.
Also the white version has differenty pads as the old version (which I have) and is 'brighter' by default.
As pads wear out they become thinner also changing the sound slightly but slowly.
Most headphones have a dip around 3-4kHz (including Paradox and HP50) and this makes them 'warm' and laid back sounding.
A bit 'speaker like' as you will.
To me the dip is perceived as 'lacking in clarity' and prefer headphones to be ruler flat.
It MAY be an acquired taste from me that I have grown accustomed to BUT when listeing to 'flat' headphones on WELL recorded music it sounds soo realistic I don't hear the 'equuipment' any more.
That must account for something, at least it does for me.
Tyll uses the a 'wrong' correction so ALL of his measurements are skewed downwards above 3kHz.
Instead look for Golden Ears and the newer Changstar measurements, they are closer to the 'truth'.
Tyll's plots can still be used for comparing between his own plots though.
Cups do NOT control excursions in the tiniest bit (cabinets do with speakers but speakers and headphones have very little in common, the same rules do not apply in general).
The excursions are controlled by the driver itself.
How well someone perceibes bass depends on pads, driver distance and 'leakage'.
The excursions remain the same under varying circumstances unless you really 'suffocate' the drivers with too much wool.
This tends to be audible.
HD650 also measures well at higher SPL so it is no problem.
I sometimes listen quite loud (you can with good headphones) and never had any problems with subbass on the filtered HD650.
Also in MOST music 20Hz isn't really there.
Perhaps in rare church organ music or movies with big rumble sounds.
In most cases 60Hz is about the lowest you will see.
It is shelving by the way and increasing in lower frequencies but does reach a limit at lower frequencies (think TT rumble).
The filter for the garage1217 amps still needs to be developped from scratch.
Knowing Jeremy it may not be before X'mas before he starts working on it (spare time related, not lazyness or lack of enthusiasm) and may be more than 6 months for him to finish it.
The filter also will have an on/off (power) switch that switches both the amp and filter and a 'filter bypass' switch.
He also wants to create an input selector (3 inputs) as a bonus and has other wild ideas that I may need to talk him out of
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IF you want you can 'audition' the filter and hear what it does.
Either send me a few songs you like to hear or tell me which songs you want and I can record them through the filter.
If you play back those recordings it is exactly what the filter will sound like when you own it.
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