return to tranceaddict TranceAddict Forums Archive > DJing / Production / Promotion > Production Studio

 
Headphone output impedance questions
View this Thread in Original format
cryophonik
I'm using the BeyerDynamic DT-880 headphones and the headphone output on my MOTU 828mkII is very quiet compared to most headphone outputs when using the DT880s, and I've also noticed that when I plug them into my computer speakers (Bose 2.1) headphone output, it's also relatively quiet. I rarely listen to music at high outputs (aside from short reference tests), but even at maximum headphone output, they are at a comfortable level for long-term listening. When I plug my Sennheiser HD280Pros into those same outputs, they are much louder.

I also have a Behringer HA4700 4-channel headphone amp that I use with two pairs of the HD280s for tracking - I don't use it for mixing because it has tone controls, etc. and it notably colors the sound, even at the 0-positions. But, when I use the DT880s with that amp, I have no problem getting them to an unbearable listening level.

So, I'm thinking that the issue is an impedance issue? Here are the impedance specs:

BeyerDynamic DT880 Impedance: 250 Ω

Sennheiser HD280Pro Impedance: 64 Ω

Behringer HA4700 Output:
- Maximum Output Power: +24dBm (load impedance 100 Ω )
- Minimum output load impedance: 8 Ω

MOTU 828mkII Headphone Output: can't find the specs anywhere

BTW, the DT880s are also available in 32 and 600 Ω versions, but I have the 250 Ω version. So, my questions (finally!) are:

1) does anybody know the output power/impedance for the MOTU 828mkII headphone output?

2) am I correct in thinking that the output impedance for the 828mkII is not a good match for the DT880s?

3) Would an impedance mismatch cause coloration of the sound? I know that my Focusrite ISA preamps have variable impedance for the mic inputs, which is used for coloring the input sound, so it seems that the same concept would apply to headphone outputs?

4) If I were to buy a dedicated headphone amp for the DT880s (for mixing), what should I be looking for in terms of output power/impedance? Any recommendations for a headphone amp for these cans (but, please don't just throw out your favorite headphone amp without considering this entire discussion!)

Oh, and before you ask, yes I have had my hearing tested numerous times over the past decade, don't listen to loud music regularly, always wore earplugs back in the day when I played/ran sound 5 nights/week, and most people are amazed that I can hear people whispering at the other end of my office, so it's not a hearing issue. ;)
West27thPrgrsv
Alright Peep this. Headphones impedance should be the same as the headphone amp you are ing with for optimum performance and maximum power output.

ohms law: voltage = current * impedance

So lets aply this law to real life

One volt will produce a current of one amp if applied to an impedance of one ohm.

So as you can see (if you got brain in your head) Impedance is just another way of saying much load x headphones place will place on your headphone amp.
Capish?

As with everything when specking out headphone amps and headphones remember this:

Low is pro ;)
Low into high will fly high into low won't go.
West27thPrgrsv
BTW did you get any good remixes for the No one knows track?
That was flyyyyyyyyy :disbelief
cryophonik
Great - thanks for the thorough reply West27thPrgrsv! What about the "coloring" question - does it make sense that mismatched impedances (assuming that they are pretty drastically mismatched) would audibly alter the sound?

quote:
Originally posted by West27thPrgrsv
BTW did you get any good remixes for the No one knows track?
That was flyyyyyyyyy :disbelief


Thanks! We had some awesome remixes done and there is talk of submitting those remixes to some labels. I actually just got a few more remixes sent to me over the last 24 hours.
CLICK TO RETURN TO TOP OF PAGE
 
Privacy Statement