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Headphone amplifiers and high impedance headphones

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#1
I need help from the knowledgeable people here. If I want to drive a high impedance headphone, e.g. DT880 600 Ohm, what output power should my headphone amplifier have?

The DT880 600 Ohms has a sensitivity of 97db. According to this chart you would need 63 mW to drive the 880 with 600 Ohms with max output.

https://nwavguy.blogspot.com/search?q=more+power+

More or less any headphone amplifier discussed here , Objective2, Atom, Lake People 109, can do that.

Are there headphones on the market that are even higher in impedance? Does it make sense to look for a headphone amplifier with more output power? So I don't have to buy a new headphone amplifier when I might want to buy high a headphone with even more impedance than one of the 600 Ohm Bayers in the future.
 

solderdude

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#3
You need higher gain and higher output voltage for high impedance headphones.
^This^
Are there headphones on the market that are even higher in impedance?
A lot of 'active' headphones are higher but that doesn't count.
These 600 Ohms are currently the highest impedance headphones. In the old days 1.4k and 2kOhm also existed.

You will need an amplifier that can provide at least 8V in SE outputs = 100mW in 600 Ohm and 200mW in 300 Ohm that will get you to 114dB SPL peak.
It will need to have 4x (+12dB) gain at least.
Balanced requires modification of the headphone amp so alas a powerful balanced amp is not going to help here.

I know Topping is working on an amp specifically for this type of headphones but there are plenty of other amps suited to drive this headphone.
 

MRC01

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#5
... You will need an amplifier that can provide at least 8V in SE outputs = 100mW in 600 Ohm and 200mW in 300 Ohm that will get you to 114dB SPL peak. ...
These output levels seem really loud. I don't think an amp that powerful is necessary.

FWIR, the 600 ohm DT880 voltage sensitivity is 97 dB / V. So, 8 times the voltage means doubling it 3 times at 6 dB, or 18 dB louder, which is 115 dB. Or, 20*log(8) = +18 dB. I'd call that "super ultra mega" loud. It is an SPL that for me personally, causes instant pain. Why would anybody need their headphones to go this loud?

If the headphone amp had only unity gain, with an input 2 V = output 2 V that would be 103 dB SPL with this headphone. Even that is very loud, probably OK for the occasional biggest dynamic crescendos but I wouldn't want it any louder. And that would only be for high dynamic range music because I wouldn't want average/continuous levels above 80-85 dB.

This particular headphone has lowish voltage sensitivity. Most headphones will play louder for the same voltage. The conclusion is that most headphone amps have FAR more power than is needed and hearing damaging levels are well below their continuous operating limits for voltage & power.
 

solderdude

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#6
Why would anybody need their headphones to go this loud?
The reason is that 115dB peaks in music are not painfully loud at all. 115dB average or continuous is. The key words here are music and peak levels without distortion. see this.. keep in mind the 600 Ohm in question needs even more gain and voltage than the HD650 in the linked article.

Should someone want to play a song for say 20 seconds pleasantly loud without distortion then 115dB peak levels (including headroom) is what one wants. For 'normal listening' at 80-85 dB average (which is comfortably loud) and listening to well recorded or classical music you will have peaks reaching 100dB easily. So if you want to go louder, even for a short period you will need to reach 110dB. Add some headroom (because amps usually perform best below their maximum ratings and you're there.

I agree that in most cases people do not need more than 1V or so (output level from a phone)
 
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MRC01

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#7
... The reason is that 115dB peaks in music are not painfully loud at all. 115dB average or continuous is. ...
Sure, exposure time is important! But 115 dB is still painfully loud to me, even for a brief peak. NIOSH safe exposure time at that level is measured in seconds, not minutes.

... keep in mind the 600 Ohm in question needs even more gain and voltage than the HD650 in the linked article.
Right, it's quite low voltage sensitivity, less than the HD650 or HD600, which themselves are less sensitive than most others. So any amp that can adequately power it, can handle just about any other headphone. Except for rare exceptions like the HE-6.

... I agree that in most cases people do not need more than 1V or so (output level from a phone)
Yep. And even a measly 1 V to this heaphone gives 97-98 dB which is too loud for continuous listening. What can be confusing is how non-linear this is. The logarithmic amplitude response of our hearing means a little louder takes a lot more voltage & power.
 

solderdude

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#8
Sure, exposure time is important! But 115 dB is still painfully loud to me, even for a brief peak. NIOSH safe exposure time at that level is measured in seconds, not minutes.
peaks are ms not seconds.

Right, it's quite low voltage sensitivity, less than the HD650 or HD600, which themselves are less sensitive than most others. So any amp that can adequately power it, can handle just about any other headphone. Except for rare exceptions like the HE-6.
There are plenty of amps that can drive high impedance headphones well but sruggle with low impedance headphones due to limited output current capabilities.

Yep. And even a measly 1 V to this heaphone gives 97-98 dB which is too loud for continuous listening. What can be confusing is how non-linear this is. The logarithmic amplitude response of our hearing means a little louder takes a lot more voltage & power.
I have heard and measured 600 Ohm Beyers and can assure you 1V isn't nearly enough. You'll get very soft sound which isn't strange as 96dB peaks in music means average levels (which would be the continuous equivalent) would be around 80-85 dB at best which is a normal listening level and certainly not too loud.

Again... peak levels in music is not the same as A-weighted continuous levels one sees in the 'warning' labels.
 

RayDunzl

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#9
Reference Point:

My UMIK-1 measures the peak of an energetic handclap at about meter at 125dB.

1608187262443.png
 
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solderdude

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#11
My UMIK-1 measures the peak of an energetic handclap at about meter at 125dB.
Is it unbearably painful to you ?
It will be if you put it on a continuous loop and reproduce it at the same SPL though.
 

RayDunzl

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#12
Is it unbearably painful to you ?
No.

It will be if you put it on a continuous loop and reproduce it at the same SPL though.
With what interval between how many claps?

---

The immediate topic (I thought) was peak vs continuous.

You can survive a peak level that would be deleterious if continuous.

A vigorous hand clap is something everyone can perform that creates a high peak level without much preparation, and survive.
 
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Thread Starter #14

solderdude

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#15
A gunshot is about 160dB and is many many dB's louder than a drumhit that is 'doctored' to sound good at normal listening levels at 115dB SPL.
That 160dB is damaging so not really comparable.

In any case.. if one wants to turn up a headphone to very impressive levels and not reach distortion levels at that point one should calculate max. voltage for 120dB SPL level (which is not equal to Phon). Needless to say about 100dB peak level is needed for normal listening pleasure.
It seems very high but that's just numbers.
 

tomchr

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#17
115 dB! Pfft! How about 120 dB? :)

Actually, somewhat serious. Many aim for 120 dB peak SPL. Probably because it's a nice and round number. OP mentioned the headphones are 97 dB (per mW, presumably) efficient. So, math:

Power needed: 120-97 = 23 dBm. (dBm = dB relative to 1 mW).

Power levels in dB are calculated as: P(dB) = 10*log(P/Pref). This means that each factor of 10 increase in power results in 10 dB higher power. It also means that a 3 dB increase in power is a doubling of the power. Those tidbits makes the following back-of-envelope math possible:

23 dBm = 10 dBm +10 dBm + 3 dBm, which is the same as multiplying the reference power by 10*10 = 100 and then by 2. In other words, you need 200 mW into your 600 Ω phones to get 120 dB SPL.

If you'd rather have 115 dB SPL, the math is this: P = 10^((115-97)/10) = 63 mW.
And just checking the back-of-envelope math: For 120 dB SPL, you'll need P = 10^((120-97)/10) = 199.53 mW.

Tom
 

restorer-john

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#18
The immediate topic (I thought) was peak vs continuous.

You can survive a peak level that would be deleterious if continuous.

A vigorous hand clap is something everyone can perform that creates a high peak level without much preparation, and survive.
Many people, it appears, can't understand the difference.

The classic EIA toneburst will sort the sheep from the goats. My guess is 99% of the respondents in this thread, don't even know what that is, letalone have tested it.
 

solderdude

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#19
115 dB! Pfft! How about 120 dB? :)

Actually, somewhat serious. Many aim for 120 dB peak SPL. Probably because it's a nice and round number. OP mentioned the headphones are 97 dB (per mW, presumably) efficient. So, math:

Power needed: 120-97 = 23 dBm. (dBm = dB relative to 1 mW).

Power levels in dB are calculated as: P(dB) = 10*log(P/Pref). This means that each factor of 10 increase in power results in 10 dB higher power. It also means that a 3 dB increase in power is a doubling of the power. Those tidbits makes the following back-of-envelope math possible:

23 dBm = 10 dBm +10 dBm + 3 dBm, which is the same as multiplying the reference power by 10*10 = 100 and then by 2. In other words, you need 200 mW into your 600 Ω phones to get 120 dB SPL.

If you'd rather have 115 dB SPL, the math is this: P = 10^((115-97)/10) = 63 mW.
And just checking the back-of-envelope math: For 120 dB SPL, you'll need P = 10^((120-97)/10) = 199.53 mW.

Tom
Correct... if the 97dB/mW assumption is correct.
However, my table says it is 94dB/mW and 96dB/V.
It will also directly show the needed power, voltage and current for this headphone at 90dB, 105dB and 120dB peak levels.
Saves you doing the math for a lot of headphones. :)
 

MRC01

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#20
... My UMIK-1 measures the peak of an energetic handclap at about meter at 125dB.
...
When I've recorded live acoustic music at various venues, the clapping typically peaks as loud as the loudest parts of the music. If you play it back with the music at normal listening levels, the claps are nowhere near 125 dB. That said, vigorous loud clapping can exceed my pain threshold if I'm in the audience.
 
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