What are the characteristics and measurements of properly driven/driving headphones/amplifiers?

[platimn]

I see these phrases a lot to describe differences in head-amplifier performance as thresholds and as comparative qualities. Another one that is used is "authority." Are there any measurements beyond power delivery and gain that support these claims? Even with insensitive headphones the difference between the highest power amplifier and relatively anemic entry models is only several decibels beyond the "pain" threshold. Are there other measures that factor into this? What can be used to predict whether an amp has "authority" or not based on specifications and measured performance?

 

[Robin L]

I see these phrases a lot to describe differences in head-amplifier performance as thresholds and as comparative qualities. Another one that is used is "authority." Are there any measurements beyond power delivery and gain that support these claims? Even with insensitive headphones the difference between the highest power amplifier and relatively anemic entry models is only several decibels beyond the "pain" threshold. Are there other measures that factor into this? What can be used to predict whether an amp has "authority" or not based on specifications and measured performance?

"Authority" is a subjective term that is effectively meaningless, typical boilerplate in subjective discussions. What is needed in a headphone amp is low self-noise and distortion, and enough power into drive headphones without clipping. The rest is gaslighting. Lots of subjective fora and review sites would say otherwise, but as there's money in this sort of thing, they won't/can't be stopped, so there will always be someone making subjective claims that are not confirmed by measurements. Additional power beyond what is necessary to drive headphones to their maximum level without clipping is wasted. You don't need 5 watts to drive Sennheiser HD 650 headphones, and though there are few headphones [electrostatics, planars] that require more power, they are not common.

 

[platimn]

"Authority" is a subjective term that is effectively meaningless, typical boilerplate in subjective discussions. What is needed in a headphone amp is low self-noise and distortion, and enough power into drive headphones without clipping. The rest is gaslighting. Lots of subjective fora and review sites would say otherwise, but as there's money in this sort of thing, they won't/can't be stopped, so there will always be someone making subjective claims that are not confirmed by measurements. Additional power beyond what is necessary to drive headphones to their maximum level without clipping is wasted. You don't need 5 watts to drive Sennheiser HD 650 headphones, and though there are few headphones [electrostatics, planars] that require more power, they are not common.

That is what I seem to gather from here. But apart from the high voltages required by electrostats, are there any measurements that support a sort of quality curve for higher power into planar headphones apart from the sensitivity values given and predicted dB SPL? Many of them can be driven to high listening volumes even at relatively low power compared to their stated maximum RMS values. Are there changes in magnetic field interactions that maybe manufacturers are observing in their own testing? Or is it simply increasing loudness that sounds better to the human ear (and the higher power required) that underpins all of the above?

 

[DVDdoug]

"Authority" is a new one for me! But yeah, it means whatever you want it to mean... "Audiophiles" and reviewers use a lot of meaningless words. I'd ignore anything other than clear language... If they say "it goes loud", or the "the bass is weak", or "I can hear distortion", those words have real meanings.

There's output voltage (or power*) as well as noise, distortion, and frequency response, and that's about it!

Distortion is almost always below audibility unless you drive the amp into clipping. If you have an integrated DAC/amp the amp usually has enough headroom to it's impossible to clip the analog amplifier... You'll only get clipping if the digital data is clipped (which can happen if you boost with digital EQ).

Frequency response is almost always flat except if the source impedance is too high (relative to the headphone impedance). The headphone impedance isn't flat across the audio range and the impedance variations can result in frequency response variations. Most headphone amplifiers have low-enough impedance that this isn't a problem, and higher impedance headphones are more immune to this.

Noise can be an issue with some computer soundcards, and of course more-sensitive headphones make everything louder including the noise. Noise is most noticeable when there is no signal or when the signal is quiet. Often the noise doesn't go down when you turn-down the volume control, and any noise generated in the amplifier doesn't go down if you turn-down the digital volume so if you listen at low volumes the signal-to-noise ratio can be worse and sometimes distracting/annoying.

Even with insensitive headphones the difference between the highest power amplifier and relatively anemic entry models is only several decibels beyond the "pain" threshold.

I don't have a dedicated headphone amplifier but my laptop only goes "moderately loud" (with any of my headphones). Plus I use ReplayGain with music which brings-down the volume on most songs. The headphone-output on my receiver goes plenty-loud.


* Power (wattage) depends on voltage and impedance (lower impedance means more current and more power). Then, sensitivity depends on how efficiently the electrical energy is converted to acoustic energy.

 

[Robin L]

"Authority" is a new one for me! But yeah, it means whatever you want it to mean... "Audiophiles" and reviewers use a lot of meaningless words. I'd ignore anything other than clear language... If they say "it goes loud", or the "the bass is weak", or "I can hear distortion", those words have real meanings.

There's output voltage (or power*) as well as noise, distortion, and frequency response, and that's about it!

Distortion is almost always below audibility unless you drive the amp into clipping. If you have an integrated DAC/amp the amp usually has enough headroom to it's impossible to clip the analog amplifier... You'll only get clipping if the digital data is clipped (which can happen if you boost with digital EQ).

Frequency response is almost always flat except if the source impedance is too high (relative to the headphone impedance). The headphone impedance isn't flat across the audio range and the impedance variations can result in frequency response variations. Most headphone amplifiers have low-enough impedance that this isn't a problem, and higher impedance headphones are more immune to this.

Noise can be an issue with some computer soundcards, and of course more-sensitive headphones make everything louder including the noise. Noise is most noticeable when there is no signal or when the signal is quiet. Often the noise doesn't go down when you turn-down the volume control, and any noise generated in the amplifier doesn't go down if you turn-down the digital volume so if you listen at low volumes the signal-to-noise ratio can be worse and sometimes distracting/annoying.

I don't have a dedicated headphone amplifier but my laptop only goes "moderately loud" (with any of my headphones). Plus I use ReplayGain with music which brings-down the volume on most songs. The headphone-output on my receiver goes plenty-loud.


* Power (wattage) depends on voltage and impedance (lower impedance means more current and more power). Then, sensitivity depends on how efficiently the electrical energy is converted to acoustic energy.

I have a dedicated headphone amp [Topping L30, with its companion DAC, the E30]. My ears give up before the amp or headphones [Drop 6XX] do. In fact, most of the distortion one would hear with very high volume is generated by the ear. Something usually not mentioned, but a reality. Loud rock concert, ears ringing? Distortion produced by the ear [in addition to the distortion created by the musicians, which in rock is very high]. Same with headphones. In all these discussions of audiophile concerns, the overall crappiness of human hearing is never discussed. But with a lot of headbanging music, a whole lot of distortion is generated by the ear and/or the ear/brain connection.

Amps and DACs are a solved problem. But all transducers distort, particularly the human hearing apparatus. There's plenty of sub $300 dollar options for DAC/Headphone amp combos that exceed the limits of human hearing. But it's impossible to find speakers, phono cartridges or headphones that don't have some audible distortion somewhere. Also microphones, which are all over the place in response and distortion.

 

[Malaj]

Its tricky indead to describe what you hear.

With magneplanars like lcd 2 and ether c Flow it really put a questionmark that if it goes loud it can drive it idea.

I tried relatively high powered headphone amplifiers but they do appear to lack some control over the driver with lower detail retrieval and more one note bass for example as a result. Besides softened dynamics.

Though you do get volume to split your head. The more powerful they get the closer to my various stereo amplifiers/receivers so certainly appear to be power related.