Are multidriver IEMs still minphase devices?

[Davidbraham1983]

If I'm not mistaken, single driver headphones and IEMs are known to be minimal phase systems and thus can be completely described with impulse response and distortions plot. But what about IEMs with a bunch of drivers inside with a crossover network? I don't know which order XO is usually used in them, so I'm wondering if these IEMs are still minimal phase or the phase deviations are low enough to be omitted?

 

[AnalogSteph]

The drivers inside these are spaced like what, a few millimeters apart? Sounds like that should be well below the wavelength of audible sound (min 1.7 cm @ 20 kHz), so I don't see how there could be much of any comb filtering going on. There may be literature on how to size SAW filters out there which could provide further insight (SAW filters are linear phase).

 

[Tarnith]

The drivers inside these are spaced like what, a few millimeters apart? Sounds like that should be well below the wavelength of audible sound (min 1.7 cm @ 20 kHz), so I don't see how there could be much of any comb filtering going on. There may be literature on how to size SAW filters out there which could provide further insight (SAW filters are linear phase).

I wouldn't expect a massive difference due to driver placement, more crossover design and driver mating. Some of this may be more obvious, or easier to see with both time and frequency plots.

Personally I'm always a fan of being able to view a system in a few domains, even if one contains most of the information. It can make it more obvious/clear what the underlying process is that's going on and how that translates to a given frequency response.

Sorry to bump an old thread, searching around looking for anyone who's actually done time and frequency measures of modern IEMs and came across this