Yes, it is 4v I added another 4 without noticing.
I have two questions, I don't know if you could answer them.
How do you measure the level of loudness of your headphones? I tried searching an app to tell me to how much dB I'm listening music but I can't find one.
I'm a noob audio enthusiast, my question was referred to my HD600 pairing with my mobile phone dac/amp Moondrop Miad 01, do you know if this phone (which have a balanced output) could move correctly and efficient all the dynamics from the headphone? Normally I tend to listen to low level volumes, so I'm not a loudness guy but I want to know if I'm taking advantage to all the juice the headphone have to offer since it is 300 Ohms and some forums also suuggest his real sensivity is higher marking it at 350 Ohm.
As I said earlier I'm a nooby, what I post were some thoughts I made with ChatGPT but I only understand just a little small fragment.
Thanks for your answer, have a good day
Finding out accurately our listening level is complicated. The way I do it uses things you are unlikely to have(mic+coupler, a reference IEM with an individual certificate giving the sensi(er4sr), and some plugs, so I can feed the IEM and measure the voltage with a multimeter at the same time. Then I use a cheap dummy head with the same IEM and voltage and I calibrate that to the same SPL. Not many people have or care to have the tools to try that).
That why I suggested a cellphone app, but there is always a mystery about how it's calibrated, if at all. Maybe a decade ago I remember someone had tested a few cellphones with a given app, and in that specific case, the app was basically calibrated to that version of the iphone and was wrong for all the other phones.
I do not know if someone has tried that with modern phones.
Even if you get an app, and it works great, what you'll measure is likely to be less than what you'll get on your head, because you lose a lot of energy when the headphone isn't properly sealed on your head. You can check that yourself by pulling a headphone just a centimeter away when it's on your head, and the music becomes way quieter(the most impact is a loss of bass). So ideally, you'd try to make something with cardboard, with an opening as tight as possible where the mic of your cellphone gets through the cardboard, and you use said cardboard to seal against the pad on one driver.
It's not ideal, but it will hopefully give you a more realistic SPL value from an app. Again, I cannot say if the app by default will be correctly calibrated. The results could be meaningless. I don't know how to verify that without all the stuff I use.
About driving the HD600 correctly. I don't know how to answer that without jumping into the eternal fear of missing out that makes audiophiles try to solve even the problems they never had. It's not a portable headphone, so there is that. In general, it is better to look for portable headphone to use with portable gears. There is no deep law of physics being that, but it's probably a good rule of thumb.
If you look at owners of that headphone, you'll find many to tell you that it "scales up very well", meaning that the better the amp, the more you get to hear what that headphone really can do. I've heard, even people I generally trust, say so for that headphone. I honestly cannot tell you if it's true or if people are feeding their own delusions that more is always better.
It's a complicated question because you'll find different amplifier designs with their own issues, but also because it's extremely rare for people to do a blind test with the same listening level on both amps to try and check if what they experience is really just about the sound.
So, I set my listening with an app that can tell the dB you listen to between 100dB to 108-109dB and also put a preamp gain of -10dB?
Not sure what you mean by this?
The HD600 is a fantastic headphone, but the 300 ohm rating is conservative, the bass region peaks at 511ohm so you need more power to get the full bass dynamics out of them. I've had every Sennheiser except the HE-1 Orpheus and tested them with everything from an Apple 3.5mm USB adapter to a Topping A70Pro. There's a phone app called "decibel meter" on the Google playstore and it's free. Best to use an online test tone generator for consistent results. You can get things loud, but if there's not enough current to handle the voltage swings in the bass region, it's going to sound less impressive. There's some headphones that measure their OHM rating as consistent and flat, those are a lot easier to judge if they're powered enough just by turning up the volume and hear if it's loud.
Your worry is sort of justified depending on the amplifier, but lack of current shouldn't be the explanation when 500ohm will draw less current than 300ohm.