[HawaiiR]

Hello!

So I generally understand that the higher the impedance, the more power you need, and I have a dac/amp stack to meet the needs of my more power hungry HP's. That's not what this post is about.

What I actually AM confused about is why my LCD-XC (32Ω) and ATH-AD2000 (40Ω) seem to require less juice than my AEON RT (12Ω). If the AEON is more efficient, and with lower impedance than the other two, shouldn't it require less power and thus sound perfectly fine with say a laptop or phone? Instead, the opposite is true.

What am I missing here?
If any of you kind head-fiers would be nice to enough to explain this to me, I'd be most appreciative.

 

[HipHopScribe]

Lower sensitivity. The LCD-XC is 100 dB/1mW. The Aeon RT is somewhere in the low 90s if memory serves

 

[HawaiiR]

I see. I wasn't aware of that. I'll do some more research on sensitivity.
Thank you!

 

[Paul Mohr]

I am not sure how it works with headphones but with regular speakers it takes more current to drive a lower load. Hooking a 4 ohm speaker up to your amp vs an 8 ohm doubles the wattage. So 100 watts into 8 ohm and 200 watts into 4 ohms. This is why many budget amps will not drive a 4 ohm load. They just go into protection mode and shut off.

I would assume it works in about the same way with headphones. You also have to take into account the sensitivity of the driver and the type of driver. I would think a 12 ohm headphone would almost require a speaker amp, or a really robust headphone amp. Certainly not something putting out a few hundred miliwatts. However like I said it depends on the drivers and how effecient they are. I have two headphones. My K371s are 32 ohms. And my sundara's are 37 ohms. The 371's can be driven by just about anything, very easy to drive. Even though they are 32 ohm. The difference is they closed back normal drivers with a sensitivity of 114db. The sundaras are open back planar's with a sensitivity of 94 db.

If you look at headphone amp specs they will list output power at different loads. High empedance loads are normally in the milliwatts. Once you get into 32 and 16 ohms they are rated much higher. Like almost a watt to 2 or 3 watts. This normally means they have the current available to do that. As in better power supply and all that. An amp that doesn't have a lot of current avialable to it is going to have a hard time driving a lower ohm driver. And just becaues an amp will drive a headhpone doesn't mean it will sound that good. It might lack bass, control and dynamic range. My phone will barely drive my sundara's, but it will drive them if you don't want it loud. And it will drive my K371's just fine, louder than most would listen too. That being said they both sound much better on a more powerful amp even though I don't have to turn the volume up as high.

Same thing happens with house speakers. I have an AV receiver rated at 100 watts per channel and it weighs maybe 3 or 4 lbs. It will run my speakers just fine and will loud enough to reach THX standards ( I think its 110db?) That being said they don't sound really great. They lack dynamic range and bass. You pretty have to use a powered subwoofer with them. I have another older receiver (technics AX-A7 I think?) that weighs like 25lbs, has built in cooling fans and drive a 2 ohm load. This thing sounds way better and has none of the issues the other receiver has. Even though they have the same RMS power ratings. One of the main differences being I am sure it can put out more current.

 

[mauaudiocr]

Is not just impedance, you also need to consider sensitivity, if sensitivity is low or kinda low on a headphone then an amp will have a harder time to drive the headphone, it seems the RT has a sensitivity of 91 which is low(esh), that might be the reason when you compared to the other headphones the AEON RT is not as easy to drive, the LCD-XC it seems to have a sensitivity of 100, the ATH-AD2000 it seems to have a sensitivity of 102, so the LCD-XC and the ATH-AD2000 are very efficient headphones compared to the AEON RT.

 

[HawaiiR]

Thanks everyone. I had not considered, or was even aware of, the sensitivity. That makes sense, or at least I know it will once I research it a bit. Appreciate you all pointing me in the right direction on this topic.

Cheers!

 

[jonathan c]

I see. I wasn't aware of that. I'll do some more research on sensitivity.
Thank you!

~ When comparing the sensitivity of headphones, you will come across ‘dB/mw’ and ‘dB/V’ (decibels per milliwatt and decibels per volt).
~ The first does not take the ‘stated’ impedance into account, the second does take the ‘stated’ impedance into account. Thus, dB/V is a better metric for evaluating headphone sensitivity, especially when low-impedance vs high-impedance headphones are being considered.
~ The value of a dB/V reading may not convey much in itself but the usefulness comes in the comparison across different headphones.
~ Enjoy the research!

 

[MtnMan307]

I have the Aeon Closed RT and it does take a lot of juice. I have a Jot 2 and a Lyr 3 and I probably wouldn’t go much lighter on the amp.

 

[jonathan c]

I have the Aeon Closed RT and it does take a lot of juice. I have a Jot 2 and a Lyr 3 and I probably wouldn’t go much lighter on the amp.

Just for info….your Aeon has a standard sensitivity of 85.9 dB/mw; its 12.5 ohm stated impedance produces a sensitivity of 104.9 dB/V. In comparison, the Sennheiser HD-600 has a standard sensitivity of 100.6 dB/mw; but its 300 ohm stated impedance produces a sensitivity of only 105.7 dB/V.

 

[HawaiiR]

I have the Aeon Closed RT and it does take a lot of juice. I have a Jot 2 and a Lyr 3 and I probably wouldn’t go much lighter on the amp.

Thanks! I currently have a Modius + Lyr 2 stack. My AEON Closed RT (and other HP's) work beautifully on that system.