can someone tell me what is speed?

Speed, I believe, is how quickly notes transition from one to another. It's going to be more difficult to hear if you don't have any experience with playing instruments, but it's still possible to pick up on. Try to find a guitar or piano or drum solo in a favorite song of yours. Do the notes sound slurred together like something you'd hear on the radio, or do they feel individual like you could pluck them out of the air?

Haha...I saw the title and thought..."Well it's this white powder that you cut into lines....." lol! Anyway my last cheapo headphones were slow and muddy/wooly sounding compared to my Grados. Part of being fast is clean, crisp, dynamic, starting and stopping notes instantly, that razor sharp leading edge to sounds.

good way to know is to listen to an extremely slow headphones ( beats solo ) and a very fast one

first thing u realized is that in the beats , the moment the bass comes in , it takes awhile to fade away before u start hearing other other parts of the music ( some tiny exaggeration here ) because the driver are not fast enough  , when the headphones are fast , nothing seems to over lap each other because the driver can product things quickly enough.. 

headphone that lacks bass seem to be faster because bass is always a problem when it comes to speed. Many headphones seem to be slow in this area.. IMO open cans tend to be faster sounding because theres no resonance

to me at least :D my 2 cents

So in essence it would be the note decay. I think bass would be the most noticeable out of all the frequencies. Since turning my denons into open-back the separation is markedly better and bass is much more detailed. Treble does linger a bit but it adds to that airy feeling.

Yes to all the above descriptions. As already mentioned, a guitar riff is a good test on testing the speed or how the transducer reacts to one quick note to the other.  One song I use is Metallica's "Blacken".  Each pluck is its own and never slurs or blends with the next unless it's intentional.

Forgot to mention that according to my experience, speed is the last character that fully matures, especially with dynamic transducers/drivers.

YES!I agree this : I believe, is how quickly notes transition from one to another. It's going to be more difficult to hear if you don't have any experience with playing instruments, but it's still possible to pick up on. Try to find a guitar or piano or drum solo in a favorite song of yours. Do the notes sound slurred together like something you'd hear on the radio, or do they feel individual like you could pluck them out of the air?

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