What Does 5mw, 18mw, 20mw Output Mean To Me?

[bland10000]

I've been reading posts that mention the size of headphone output i.e. 5mw, 18mw, 20mw... Is that telling me the 20mw is four times as loud as the 5mw?

(perhaps this belongs in "phones" section rather than tech. topics)

[Fat Tires]

I have moved the topic.

The difference in the wattage of these amps allows a user to use less efficient phones with the player. Therefore you can use a harder to drive pair of phones like a pair of AKG 240s phones with an iPod to higher volumes than a minidisc unit can drive them to. Since the minidisc units on the market have such anemic headphone amps they require a very easy to power set of headphones to really shine.

[ROMBUSTERS]

so which one is the best for that job?

[Fat Tires]

so which one is the best for that job?

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That's a loaded question. Everyone's ears are different.

[bland10000]

I'm reading headphone specs. at Crutchfield and Minidisco; what spec. tells us if the headphone is an easy to drive or hard to drive set?

[Fat Tires]

The lower the Ohm number, the easier it is to drive. FWIW, Sony phones tend to be very easy to drive. As do some Sennheiser models, Shure, and Grados too.

[ROMBUSTERS]

The lower the Ohm number, the easier it is to drive. FWIW, Sony phones tend to be very easy to drive. As do some Sennheiser models, Shure, and Grados too.

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thats all i needed to know

[aeriyn]

This is a loaded question.

First of all, impedance of a headphone is not the end-all of its efficiency. Sensitivity plays an even greater role in this. Why would my Shure E3cs, with 24ohm impedance, be louder at the same level as my old Shure E2cs, with 16ohm impedance?

Same can be said about E5c vs. E3c, except the impedance difference is much larger (i.e. E5cs impede 110ohms as opposed to 24).

Headphone jack output on portable devices is important because it determines what types of headphones would work best with the portable. Since human hearing is logarithmic, it takes ten times the power to make an audio signal sound twice as loud. For example, a typical MD player's output is 5mW. Another DAP, the Creative Nomad Jukebox 3, has a 50mW output; ten times the power of the MD player. At full volume, the NJB3 would be twice as loud as our typical MD player. Also, the more powerful the amp in a player, the better it tends to sound.

When it comes to using portable amplification with a DAP, a more powerful headphone output is desired, since most portable music players either don't have a line-out or they have a pseudo line-out (iPod and most DAPs included) which is merely the headphone output at full volume with effects and EQ turned off. The lower the line level signal, the higher the signal-to-noise ratio at the outboard amp is going to be, which degrades sound quality.

I often complain about Sony's insistence on installing 5mW amplifiers in their portable units because it's cutting corners. It doesn't serve much true purpose besides making the unit a bit cheaper for Sony to build. It may extend battery life, as well, but I'd rather be able to use my inefficient headphones and have better sound than have a longer battery life. Your mileage may vary however.

I'm reading headphone specs. at Crutchfield and Minidisco; what spec. tells us if the headphone is an easy to drive or hard to drive set?

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Sensitivity first, impedance second. The higher the sensitivity (in dB/mW) the more efficient the phone is. The higher the impedance, the volume will be reduced.

[Fat Tires]

Thanks for clearing that up for us.

[bland10000]

thank you Nismo, thank you Aeriyn. Due to my paying attention to the forum, I have recently learned about the importance of headphones. Before this I would buy any earbud for around 20.00 usd to replace the prior pair.