Originally Posted by Benn Beckman
guys i'm new in audio world, can you teach me how to match a headphone and an amp? like how much power do i need to drive ineficient headphone like dt990 250 or 600 and akg k7 series, q701, k612pro?
i read somewhere, but it for matching speaker with an amp not headphone. he said that i must look impedance first, for example like if speakers have spec 80mw/16 ohm so i must match an amp with 16ohm first plus 50% from speakers spec. so i must choose an amp with 120mw/16ohm.
how do you guys matching the spec like you write above? how can i match the headphone and an amp if the specs write different like this
36 mW into 300 ohms, It would drive a 250 ohm
its different ohm right?
i can't understand this either
they need 0,38mW to reach 90dB SPL how can you calculate that? what is spl?
and the last question, why certain headphone is hard to drive? i told by someone that sennheiser hd600 is easier to drive than beyer dt990 pro, but whe i look the specs both headphone
HD600: 97db and 300 ohm
dt990: 96db and 250 ohm
why dt990 harder to drive than hd600?
Well, there's quite a lot to explain.
To drive a headphone to certain level you need certain voltage.
Some headphones need little voltage to sound loud (HD598), some other headphones need a good amount of voltage to sound loud (DT880/600Ohm)
When I say "to reach 90dB" that's a measure of loudness.
Normal listening levels range about 70dB and 85dB, with peaks that can hit 100dB if listening loud.
On top of that, for a given voltage, lower impedance headphones drain more current from the amplifier. So if you have two headphones that need the same voltage (K702 and DT880/250 Ohm) the one with lower impedance will be the harder one to drive (K702).
DT990 needs more voltage than HD600 to sound at the same level, and being slightly lower in terms of impedance it drains a little bit more current from the amp.
That's why it's slightly harder to drive.
You can find a good database at innerfidelity.
Check the bottom right hand corner of each sheet and you'll find how much voltage you need for 90dB SPL.
Look how low impedance headphones like the K702 need more power than high impedance headphones like DT880/250 despite both needing similar voltage (around 0.300 Vrms)
That's because the lower impedance drains more current from the amp and so the amp should be able to provide both relatively high voltage and current.