psgarcha92
100+ Head-Fier
- Joined
- Jan 17, 2011
- Posts
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- 17
I own a pair of Low Impedance IEMs, the RE272s, rated at 20Ohms at 1KHz.
I recently read somewhere that Headphone impedance is different at different frequencies, which i could infer from manufacturers rating Headphone impedance at one particular frequency. Well, how much the impedance varied with frequency, i did not have an idea of that.
Quoting NwAvguy
"YOUR IMPEDANCE MAY VARY: Virtually all passive headphones (without their own powered electronics) have a varying impedance that changes with frequency. As described above, they don't behave like a simple resistance when driven with typical audio signals. The gold colored graph below shows the impedance, in ohms, of the Ultimate Ears SuperFi 5 Pro in ear monitors. You can see they’re only at their rated 21 ohm impedance below about 200 hz. The impedance rises to nearly 90 ohms at about 1200 hz and drops to below 10 ohms at 11,000 hz"
This scares me a bit. I have the 272s at 20Ohms, and I imagine their impedance varying from 10ohms to 30-40ohms maybe. Current handling at Higher impedance is ok, but what about current at low impedance, for instace at lower than 10ohms?
Can i have an amplifier designed for the current needs of my IEMs? Would it actually help me in getting better sound? i was looking at
http://www.ti.com/lit/an/sboa031/sboa031.pdf
But they list the nominal impedance as 40-300Ohms in this design. What else should i look at?
The aim of the amplifier is going to be able to drive the IEMs effortlessly, as in, being able to have all the current the IEMs can ever require.
Regards
I recently read somewhere that Headphone impedance is different at different frequencies, which i could infer from manufacturers rating Headphone impedance at one particular frequency. Well, how much the impedance varied with frequency, i did not have an idea of that.
Quoting NwAvguy
"YOUR IMPEDANCE MAY VARY: Virtually all passive headphones (without their own powered electronics) have a varying impedance that changes with frequency. As described above, they don't behave like a simple resistance when driven with typical audio signals. The gold colored graph below shows the impedance, in ohms, of the Ultimate Ears SuperFi 5 Pro in ear monitors. You can see they’re only at their rated 21 ohm impedance below about 200 hz. The impedance rises to nearly 90 ohms at about 1200 hz and drops to below 10 ohms at 11,000 hz"
This scares me a bit. I have the 272s at 20Ohms, and I imagine their impedance varying from 10ohms to 30-40ohms maybe. Current handling at Higher impedance is ok, but what about current at low impedance, for instace at lower than 10ohms?
Can i have an amplifier designed for the current needs of my IEMs? Would it actually help me in getting better sound? i was looking at
http://www.ti.com/lit/an/sboa031/sboa031.pdf
But they list the nominal impedance as 40-300Ohms in this design. What else should i look at?
The aim of the amplifier is going to be able to drive the IEMs effortlessly, as in, being able to have all the current the IEMs can ever require.
Regards