[stijn]

what source were you using? As far as I know, it might be possible for amplifiers etc that they reach their sweet spot only when they are warm enough, because component chracteristics change with temperature (think for example analog filter frequency response changing). Not sure that effect is large enough to audibly alter the sound though, or that the engineers designing it can even reliably aim for such a sweet spot.. Though I always had the impression when listening on my speaker setup that it sounds a bit messy the first 15 or 20 minute, then got better. Never measured it, so it's equally possible that it's just my brain adapting and cleaning up the mess for me.

 

[kuhchuk]

I was using my ipod, actually.  I don't think that ipods have any sort of warm-up period, but I've been wrong before.
 

 

[alpha10]

I do believe in burn-in, but it's a minor change if any.

Some even mentions this in the manual:

BREAK IN
Allow approximately 15–30 hours of break in at moderate listening levels before any critical listening. Like most high-performance audio reproduction devices, a break-in period should result in improved performance. For rapid break-in you may choose to leave the headphones connected to an audio source playing music during the night or when otherwise not in use.

http://www.martinlogan.com/pdf/manuals/manual-mikros90.pdf

 

[ev13wt]

^^ They also quote:

SPECIFICATIONS
(subject to change without notice)
Frequency response
. . .
6–22,000 Hz


Without a curve or drop in dB. So basically their information is worthless to begin with.

 

[jaddie]

^^ They also quote:

SPECIFICATIONS
(subject to change without notice)
Frequency response
. . .
6–22,000 Hz


Without a curve or drop in dB. So basically their information is worthless to begin with.

Another case of +/- xdB (so its always in spec). When I see unspecified tolerances I assume +/- 3dB. If the manufacturer doesn't like that then they need to state it more accurately. And frankly for any acoustic transducer that's being pretty optimistic anyway.

So post "break-in", its still in original spec.

 

[ferday]

where are these graphs showing +/- 20dB changes?
 
the suspense is killing me

 

[jaddie]

where are these graphs showing +/- 1dB changes?
 
the suspense is killing me too.