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D00M98 t1_j61skq3 wrote

Reply to comment by Altruistic_Ad5493 in Are macbook air can drive the HD600? by KapToIIIe4Ka

No, Apple dongle is not sufficient. 97 dB at 300 ohm requires 20mW to reach 110 dB SPL (for peaks and transients), or 7mW to 105 dB SPL (in the very best case where someone listen to low volume and compressed music).

Apple dongle is measured to be 3.6 mW at 300 ohm. This is 2x short for 105 dB and 5x short at 110 dB.

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blargh4 t1_j62ajy2 wrote

“Sufficient” is a question of what you listen to and how loudly. My normal listening level with loudly mastered music is about 75db peak spl and I can’t remember the last time I needed more volume than what a dongle could drive into the HD600s.

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D00M98 t1_j62cvka wrote

Don't confuse average with peak. There are easily 20-30 dB of dynamic range in the music. And can be more for audiophile recordings. If you are listening to peak SPL 75dB, then your average SPL is like 45dB, which is very unlikely.

Most people are listening to 65-85 dB average, with peak SPL reaching 105-115 dB. That is why power calculators defaults at 110dB.

https://www.audeze.com/blogs/technology-and-innovation/sensitivity-impedance-and-amplifier-power

https://nwavguy.blogspot.com/2011/09/more-power.html

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pike-perch t1_j62n2fw wrote

I have measured 100mV on the output when playing 500hz sine wave on my HD600 at my normal listening volume. That's should be around 85dB as the sensitivity is 104 dB @ 1V.

The peaks can't be higher than 85db as my volume knobs limits the output to 100mV.

Maybe I'm just listening to very low volumes.

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D00M98 t1_j640phy wrote

(Edit: Based on follow-up post below, updated calculations based on actual sensitivity and corrected for dB/V)

So I went ahead and looked up HD600 spec: https://www.sennheiser-hearing.com/en-US/p/hd-600/

  • 97 dB/V sensitivity (not the 104 dB/V as stated by previous poster)
  • 300 ohm impedance
  • 1mW or 0.55mV to reach 85 dB SPL
  • 3mW or 1V to reach 96 dB SPL

So your numbers do not the spec of the headphones.

In any case, the comment below doesn't change. Assuming your setup can output 85 dB peak, then if you listen to average SPL of 55 dB SPL or less, and assume the dynamic range in your music is 30 dB. Then you are good. Your peaks will only reach 85 dB SPL.

On the other hand, if you are at 65 dB SPL average, with 30dB dynamic range in your source, then your peaks should be at 95 dB SPL. And if your device can drive to 85 dB, then some of the peaks will be clipped. It can be hard to tell when music is slightly clipped. Like 90-95% of the sound is there. It will sound slightly compressed (less dynamic) because the max levels are cut off.

95% of the headphones have no issue with power with most amps. So people will say power is BS and there is no such thing as lack of power. But there are outliers. Some people listen to loud music. Some music recordings have high dynamics. And some headphones do require Watts of power (e.g. Susvara, HE6se).

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smalg2 t1_j672elq wrote

You got mixed up in sensitivity units: 104dB/V (not dB/mW) adds up to 84dB @ 0.1V, not 89.

So basically, 104dB/V means 104dB SPL peak with the 1V maximum output of the Apple dongle. Isn't this loud enough? I personally use 108dB/V IEMs with my Apple dongle and never set the volume above -20dB (otherwise it's just too loud for me) so that's 88dB SPL peak. The HD600 would still have 16dB of headroom at my listening level. So from a theoretical standpoint, it looks like the Apple dongle could drive the HD600 loud enough, at least for some people? Am I missing something?

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D00M98 t1_j6797g9 wrote

Thanks for the correction. So I went ahead and looked up HD600 spec: https://www.sennheiser-hearing.com/en-US/p/hd-600/

  • 97 dB/V sensitivity (not the 104 dB/V as stated by previous poster)
  • 300 ohm impedance
  • It requires 22 mW or 2.6V to reach 105 dB SPL.
  • It requires 67 mW or 4.5V to reach 110 dB SPL.
  • Etc

Apple dongle is 3.6mW or 1V at 300 ohm. No, Apple dongle is not sufficient, for most people listening to 75-80 dB with 30 dB dynamic range.

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smalg2 t1_j67grat wrote

According to a few posts the official specs on Sennheiser's website are wrong (lol) and the actual values would be 97dB/mW and around 102-104dB/V. I don't own the HD600 and have no skin in the game, but looking at the numbers it seems they would be more than loud enough for me with an Apple dongle. I mean, my current setup is loud enough despite Android limiting the volume of the Apple dongle to -20dB (0.1V) so I really don't need 110dB peak... But if you do, that's fine too! 👍

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