[IDREOS]

Am interested in the Sennheiser 280's for use with an unamped PCDP, but have some concerns if it would be suitable as it is rated at an impedance of 64ohms.

All things being equal wouldn't a 32 ohm phone be more sensitive than a 64 ohm phone?

Could someone explain the relationship between impedance rating, sensitivity rating and volume??
Thanks for your help!
Jim

 

[hempcamp]

Keep in mind that since the HD 280s are sealed and have very good isolation, you don't need the volume up as high as you would with open/semi-open phones.

My PCDP (old Sony Discman Car), iBook, and iPod all drive the HD 280s very well. Don't get too hung up on the high(er) impedence of these phones.

--Chris

 

[hero zero]

not too sure of this stuff, but lower impedence usually means that the headphones are easier to drive

higher sensitivity rating [sound pressure level] means that a pair of headphones is louder at a given volume level

anyway, just because something has lower impedence doesn't necessarily mean it's easier to drive.....I've got the Senn 280's too, and they sound just fine out of my Panasonic mp3/cd player...but my Grado SR80's don't sound as good, even though they have an impedence of 32 Ohms...but the Senn's have a higher sensitivity rating than the Grado's do...

so in the end, you need both higher sensitivity, and lower impedence for a headphone to be really efficient and easy to power....

on the side note, lower impedence headphones seem to pick up all sorts of interference such as hissing from sources, etc. so the higher the impedence, the less you'll hear them

 

[MaxHeifetz]

I think a lot of people get some physics mixed up. Impedance and resistance are not totally different things! Impedance basically is resistance...more like the total resistance of the LRC circuit since...well...life is complicated and our circuits have inductors and capacitors in them! The only difference is...the "resistance" that we give a resistor dissipates energy and the "reactance" or the resistance of a capacitor and inductor does not! How I long for the days of calculations with only power supplies and resistors. Correct me if i'm wrong (it's summer! forgive me!) but in physics terms impedance is usually named after the variable z = sqr root of (resistance^2 + (wL - (1/(wC))^2)
where wL is the "reactance" of the inductor and 1/wC is the "reactance" of the capacitor. If you like this stuff, you will be able to use phasors to calculate these values. And phasors are NOT as fun as they sound.

 

[psyco1]

That's right, they can kill...I've seen it on TV.