Quote:
Originally Posted by ljcii /img/forum/go_quote.gif
i read on a sennheiser product
"The high sensitivity of this products reveals every detail"
Is that true? The sensitivity being high, other than being able to pick up hiss, less power also picks up the minute minute details of music that others with low sensitivty are not able to pick up even when they turn up their volume high?
|
In this thread is some explanation about sensitivity and so on:
http://www.head-fi.org/forums/f4/cne...report-360717/
Here's a very good post from Cool_Torpedo from that thread:
"Many other members and I have covered this topic in other threads. Impedance is just one of the factors that we have to consider to foresee how demanding on an amp or HP output a pair of cans is.
It's true that impedance on AC is not the very same as resistance on DC, but considering that many HPs have quite flat impedance curves across the frequency response, with flat phase angles, it's quite safe equaling them when speaking of HPs.
Looking at things this way, it's also true that the higher the impedance the phones have, the more opposition they present against the current flow, so they seem to be needing more power. But this is not the whole picture. You need to see the heapdhone as a mechanical transducer which asks for electrical power to produce sound pressure level. And here is when sensitivity comes into play.
Sensitivity tells you how loud the phones will sound when applying a mW of power on them. If you have very sensitive headphones, something like 115dB/mW, it doesn't matter what's their impedance, with very little power they'll sound loud and quite good. The higher is their impedance, the less current intensity they'll ask from the output, so they can be even easier to drive than an equally sensitive pair of phones having lower impedance. Remember that power is a function of Voltage and current Intensity. More impedance asks for more voltage being all things equal. The reason why most IEMs don't need an amp to sound good is not their lowish impedance, is their high sensitivity which in most cases is well above 110dB/mW. But this high sensitivity has its tradeoff, which is that very low voltage signals, like hums and noises in the source, will be clearly heard.
As long as the sensitivity of the phones goes decreasing, you need more power to make them sound equally loud. Exactly the double of power for every 3dB you decrease the sensitivity. Hence phones rated at 97dB/mW will need 64 mW to sound at 115 dB, while the cans having that 115dB/mW sensitivity need just one miliwatt! To make matters worse, if those cans at 97dB/mW are low impedance, they'd be asking for that power more in the form of current Intensity than in voltage form.
If that's clear, then it's quite easy to understand that impedance means nothing alone, since also sensitivity should be considered, and that having a combination of low impedance and low sensitivity, is quite demanding on the power source"
But there are many other threads on this topic as well.
