So whats the deal with crossovers in IEMs?
Jan 26, 2010 at 12:11 PM Thread Starter Post #1 of 32

MrGreen

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JH13, UE18, JH16.

These all have a large number of balanced armatures over a crossover.
So, what's the scientific reason for this exactly?

How does say, 6 balanced armatures of moderate quality sound any better than 2 exceptionally good balanced armatures?
 
Jan 26, 2010 at 6:44 PM Post #2 of 32
maybe using lots of drivers enables response peaks and troughs to be evened out by overlapping etc , sort of using them as and eq.
My own single driver iem [er4] is eq'd with a passive filter network outside of the phone! [always been a little sceptical of more drivers= better, then my iem experience is limited]
6-8 transducers per phone though..phew


.
 
Jan 26, 2010 at 10:00 PM Post #3 of 32
I agree, I'm exceptionally skeptical of multiple drivers (people discount headphones for similar things all the time).

With the JH16pro, it says on the website "Double dual low-frequency drivers offer lower distortion". Generally the myth with stacking is that you double the distortion, (although this is not true) as signal:noise ratio is maintained. He're it goes the opposite way.

Also he mentions "increased headroom and greater detail and accuracy". I don't even know where to start dissecting this. Greater detail and accuracy? If things were perfect, surely 5 drivers playing the same material as a single driver produces exactly the same detail as a driver of the same quality - which would ultimately cost significantly less.

I'd like to see this on paper. Etymotic themselves actually have stated they dont intend to go for multiple armatures because there is no benefit to using more than one. At present I agree with them, and without measurements on paper the benefits of multiple armatures cannot be proven.
 
Jan 26, 2010 at 11:06 PM Post #4 of 32
well I guess if you run 2 identical transducers in parallel you will get the same spl for less diaphragm excursion per unit compared to a single unit at the same spl.
so at certain amplitudes/frequencies some distortions ought to be lower.
Plus the capacity for high spl peaks would be possible without running out of 'headroom' especially true of low frequencies.
balanced armature must sound great when banging the stops.
tongue.gif



.
 
Jan 26, 2010 at 11:53 PM Post #5 of 32
It's the same concept as speakers. A balanced armature designed for extended treble cannot reproduce a tone in the 40-50hz range, at least not at the same volume level. That's where the larger BA and crossover comes in, to take over where the smaller one rolls off.

I'm sure there are measurements you can look at. Check some FR graphs for single and multiple driver iems and compare them. I'm in a hurry so I can't right now.
 
Jan 27, 2010 at 11:12 AM Post #6 of 32
I agree that the more drivers, the more options the design engineer has to customize or eq the sound.

Here's an example of some stacked drivers, just add a sub to these Grados!
grado-39.jpg
 
Jan 27, 2010 at 8:58 PM Post #7 of 32
Quote:

Originally Posted by Punnisher /img/forum/go_quote.gif
It's the same concept as speakers. A balanced armature designed for extended treble cannot reproduce a tone in the 40-50hz range, at least not at the same volume level. That's where the larger BA and crossover comes in, to take over where the smaller one rolls off.

I'm sure there are measurements you can look at. Check some FR graphs for single and multiple driver iems and compare them. I'm in a hurry so I can't right now.



ER4P/S/B have what is essentially a flat FR and is single driver, dude.
 
Jan 28, 2010 at 2:45 AM Post #9 of 32
Quote:

Originally Posted by Punnisher /img/forum/go_quote.gif
I was quite surprised at the graph of the er6i, which I own. They sound good to me but could benefit from more low-end in my opinion.


That's a fairly valid and common opinion. Do you really need 13+ drivers to add some bass weight/impact?
 
Jan 28, 2010 at 3:23 AM Post #11 of 32
More drivers playing the same frequency range, increases effciency (ie raises the spl), hence the individual drivers excursion is reduced, thereby reducing distortion.

The principle is the similar with loudspeakers, assuming power and imdepance are fixed, adding an additional driver adds ~3db of efficiency, so each speaker doesn't have to play as loud to reach the intended spl, hence reducing distortion.
 
Jan 28, 2010 at 6:43 AM Post #12 of 32
Quote:

Originally Posted by SilverCans /img/forum/go_quote.gif
More drivers playing the same frequency range, increases effciency (ie raises the spl), hence the individual drivers excursion is reduced, thereby reducing distortion.

The principle is the similar with loudspeakers, assuming power and imdepance are fixed, adding an additional driver adds ~3db of efficiency, so each speaker doesn't have to play as loud to reach the intended spl, hence reducing distortion.



Have you got a source for those figures?
 
Jan 28, 2010 at 12:48 PM Post #13 of 32
Multiple drivers handling different bands eliminates intermodulation distortion between each band.
 
Jan 29, 2010 at 8:44 AM Post #15 of 32
Quote:

Originally Posted by MrGreen /img/forum/go_quote.gif
Have you got a source for those figures?


Having two of the same driver, being pushed with the same voltage(in parallel) will double output energy. 3dB is a doubling in volume, hence a 3dB increase with two drivers over 1.
 

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