j-curve
100+ Head-Fier
- Joined
- Apr 15, 2002
- Posts
- 489
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- 11
Modern headphones are too sensitive. How sensitive should they be? Some people find that previous favourites like the HD580 (at 102 dB/V) are hard to drive with portable players but I've had more frustration due to the opposite problem, i.e. background hiss from headphones which are too sensitive. Even the HD215 (which is only rated at 112 dB/V) throws out continuous noise from most soundcards and some headphone amplifiers too. For the sources I use, 95-105 dB/V seems to be a reasonable range of sensitivity and 100 dB/V would be optimum. [Note: Sensitivity (dB/V) shouldn't be confused with efficiency (dB/mW). This thread might help.]
Now look at some of the crazy specifications for headphones in the marketplace today. Full-size cans run up to 123 dB/V, earbuds and canal phones even higher. An inline volume control is one way to eliminate background hiss. Here's another, simpler method.
Recommended values depending on the reduction (insertion loss) desired, all resistors in Ohms:-
For -10 dB, R1=15, R2=22
For -15 dB, R1=6.8, R2=27
For -20 dB, R1=3.3, R2=27
For -25 dB, R1=1.8, R2=27
For -30 dB, R1=1.0, R2=33
NB: Consider using a 1/2 Watt resistor for R2 as it may dissipate some heat when the volume is cranked.
Input impedance is about 30 Ohms with headphones connected.
I built mine into an extension cable.
Sorry, no macro setting on the digital camera.
[Aside from busting hiss, sound quality will be improved in some cases. e.g. If you're using a portable player with a digital volume control which truncates bits, you'll hear how bad it sounds at low volume settings. That's not the fault of the headphones(!), however it is indirectly caused by the headphones because they are too sensitive.]
Now look at some of the crazy specifications for headphones in the marketplace today. Full-size cans run up to 123 dB/V, earbuds and canal phones even higher. An inline volume control is one way to eliminate background hiss. Here's another, simpler method.
Recommended values depending on the reduction (insertion loss) desired, all resistors in Ohms:-
For -10 dB, R1=15, R2=22
For -15 dB, R1=6.8, R2=27
For -20 dB, R1=3.3, R2=27
For -25 dB, R1=1.8, R2=27
For -30 dB, R1=1.0, R2=33
NB: Consider using a 1/2 Watt resistor for R2 as it may dissipate some heat when the volume is cranked.
Input impedance is about 30 Ohms with headphones connected.
I built mine into an extension cable.
Sorry, no macro setting on the digital camera.
[Aside from busting hiss, sound quality will be improved in some cases. e.g. If you're using a portable player with a digital volume control which truncates bits, you'll hear how bad it sounds at low volume settings. That's not the fault of the headphones(!), however it is indirectly caused by the headphones because they are too sensitive.]