chinesekiwi
Headphoneus Supremus
- Joined
- Feb 29, 2008
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See my first post Fras. And quit wondering as you can try my DT880/600 anytime 

Done. The replacement pair should be in next week. : )
[size=11pt][size=x-small]Dear Patrick,[/size][/size]
[size=11pt][size=x-small]Thanks for your request about DT 880/600 ohm Premium headphones.[/size][/size]
[size=11pt][size=x-small]When we build the drivers and assemble the headphones here in Heilbronn, we take highest care that nominal SPL[/size] [size=x-small] and frequency response are matching between L and R. These factors are much more critical for listening than the impedance.[/size][/size]
[size=11pt][size=x-small]Of course, we also ensure correct impedance of the drivers as a secondary issue, and a deviation like you have measured is uncritical, since nominal SPL and frequency response are matching. The exact number of coil windings is much more critical, and this is absolutely within control. [/size][/size][size=11pt][size=x-small]So please don´t hesitate about the impedance deviation.[/size][/size]
[size=11pt][size=x-small]Mit freundlichen Grüßen / Kind regards,[/size][/size]
[size=11pt] [/size]
[size=11pt][size=x-small]Gunter Weidemann[/size][/size]
[size=11pt][size=x-small]Consumer Products[/size][/size]
[size=11pt] [/size]
[size=11pt][size=x-small]beyerdynamic GmbH & Co. KG[/size][/size]
[size=11pt][size=x-small]Theresienstr. 8[/size][/size]
[size=11pt][size=x-small]74072 Heilbronn - Germany[/size][/size]
The first order of matched driver pairs is to a predetermined output level for a given input level and on the production line this is typically done programatically. The drivers are fed a signal under controlled conditions and the measured output either passes or fails the QC criteria.
Some manufacturers simply use a 1kHz tone, some use a full spectrum sweep. The output shows up on a display and it either falls within acceptable tolerance or not. If a can or driver fails the test, it is either scrapped or reworked.
This pass/fail test usually happens more than once in the process. At least once for raw drivers as they are fabricated, and then again for completed headphones as they near the end of the line. Pass/fail criteria can vary depending on the can, anywhere from +- 0.5dB for single frequency sine to +- 3dB for spectral sweeps.
The DC resistance you measure is not as important as wha the actual output level is in dB. Do you hear a difference between channels? Resistance/impedance is only part of the equation in determining the overall output level. It's the final output level that is important.
@skylab
can i ask a question?
i have ad900..and imo it's very light bass...
if i wanna add a HP (becoz i like the sound of ad900, but not the bass) would dt880 become the right choice?
since i also consider the dt990..is the dt990 can be an allround cans (jazz, pop, rock, metal)?
thx..