[RRod]

   
I am saying that an amp strong enough to attain sufficient volume is not necessarily strong enough to attain the best sound. I used the HE-6 as an example because it is well known that it requires more than just an amp that can give it enough volume.
 
True, but I'm also getting the JVC HA-SZ2000, maybe even first, since I already have the money for it. Despite having high sensitivity and being just 16 ohms, virtually every owner insists that it absolutely requires an amp to get the best sound. (But most people use it for heavy bass with EQ, so that's different than normal listening. Plus it has two drivers on each side.)

 
I'm sure none have bothered to do anything blind, so dun care. Virtually every HD800 owner says the same thing*, except those of us who have bothered to test these things in an objective way. Low impedance cans can of course have issues with sufficient current, but that should result in clipping. And I'd be worried about the amp output impedance, but then you just need a little standalone unit, not something that's a bajillion $$. stv already mentioned possible avenues of bass response problems, but we should be well away from those once we're talking about amps at Magni's level, which is what I use for my HD800s and what many owners would say is "insufficient."
 
Everyone says differences are obvious when they want to hear them. It's not compelling, especially when auditory memory is so ephemeral. Anyway, blah blah blah.
 
*note I don't mean that the HD800 doesn't need an amp; as I said, I'm talking about the assertion that you need MOAR amp than something that actually works fine but has the gall to be not pricey.

 

[cel4145]

True, but I'm also getting the JVC HA-SZ2000, maybe even first, since I already have the money for it. Despite having high sensitivity and being just 16 ohms, virtually every owner insists that it absolutely requires an amp to get the best sound. (But most people use it for heavy bass with EQ, so that's different than normal listening. Plus it has two drivers on each side.)

Sensitivity maybe be measured at a specific frequency or over a specific range of frequencies that may not include much of the bass frequencies. Plus, the 108 dB/1 mW rating of the JVC's is technically efficiency, not sensitivity, and thus if there is impedance variance, the headphones may be more or less sensitive at certain frequencies (assuming it was measured for a range of frequencies to begin with). Then add on basshead music with lots of heavy lower bass content in addition to the mids and highs--plus the tendency of bassheads to still want to EQ the bass. Not to mention listening volume (are people listening very loud?), and one can see how some users might want an amp to drive these headphones.

That being said, I see many members in that thread who like to hype stuff--IMO, they get out of control on claims about some of the JVC headphone models. So I'd say judge for yourself instead of drawing on their conclusions. You have an amp, so see what you notice instead of speculating

 

[Music Alchemist]

Sensitivity maybe be measured at a specific frequency or over a specific range of frequencies that may not include much of the bass frequencies. Plus, the 108 dB/1 mW rating of the JVC's is technically efficiency, not sensitivity, and thus if there is impedance variance, the headphones may be more or less sensitive at certain frequencies (assuming it was measured for a range of frequencies to begin with). Then add on basshead music with lots of heavy lower bass content in addition to the mids and highs--plus the tendency of bassheads to still want to EQ the bass. Not to mention listening volume (are people listening very loud?), and one can see how some users might want an amp to drive these headphones.

That being said, I see many members in that thread who like to hype stuff--IMO, they get out of control on claims about some of the JVC headphone models. So I'd say judge for yourself instead of drawing on their conclusions. You have an amp, so see what you notice instead of speculating

 
Nope, sold my amp and DAC! But I can always get another.

 

[cel4145]

Nope, sold my amp and DAC! But I can always get another.

You just wanted to sell all of your equipment so you could buy new stuff

 

[Music Alchemist]

You just wanted to sell all of your equipment so you could buy new stuff

 
I told ya that before, remember? =D
 
The STAX for serious audiophile purposes and the JVC for more fun, bass-heavy listening are a well-rounded combo...but if I get the JVC first, I may have to wait longer for the STAX.

 

[cjl]

   
I am saying that an amp strong enough to attain sufficient volume is not necessarily strong enough to attain the best sound. I used the HE-6 as an example because it is well known that it requires more than just an amp that can give it enough volume.
 
True, but I'm also getting the JVC HA-SZ2000, maybe even first, since I already have the money for it. Despite having high sensitivity and being just 16 ohms, virtually every owner insists that it absolutely requires an amp to get the best sound. (But most people use it for heavy bass with EQ, so that's different than normal listening. Plus it has two drivers on each side.)

Nope. An amp is sufficient, or it isn't. If the amp can go loud enough for the loudest transients you need, with inaudibly low distortion, a flat frequency response, and no other issues (say, impedance or crosstalk issues), it is all you will ever need for that transducer. You will not gain anything more from a more powerful amp (despite what people love to push in other sections of these forums).

 

[Music Alchemist]

  Nope. An amp is sufficient, or it isn't. If the amp can go loud enough for the loudest transients you need, with inaudibly low distortion, a flat frequency response, and no other issues (say, impedance or crosstalk issues), it is all you will ever need for that transducer. You will not gain anything more from a more powerful amp (despite what people love to push in other sections of these forums).

 
If you're saying that it can improve the sound quality of the transient peaks (even when with less power, it can still achieve the same volume level, except distorted peaks, etc.), then I agree with you; it's just that sometimes it's not clear how much power a headphone really needs. For example, one of the most common things I hear about the HE-6 is that it can sound downright awful from some amps that "should" have enough power.
 
Since you're knowledgeable about these things, would you be able to tell me how much power the JVC HA-SZ2000 would need? (Not just for normal listening, but for the boosted bass and potentially higher volumes that most owners use. Also bear in mind that it has four drivers instead of two.)
 
@cel4145 mentioned this to me:
 

This post is about why use subwoofers, but he makes a point that supports what I said about bass heavy music requiring extra amp power

 
and linked me to a post on another forum, which I will quote:
 

The power required for a different frequency ranges depend on how efficient the speaker or subwoofer is. If (and that's a big if) your subwoofer was the same effiency as your main speaker, reproducing 25Hz would require the exact same power as 2500Hz. Of course the laws of physics don't make this situation common. Once you set some maximum limit on the size of a speaker, you find that designing it to go lower in frequency can only be done at lower efficiency. A 16" cube trying to produce 20Hz could easily be so inefficient that it requires 10x the power of your main speakers. On the flip side, some of the larger subwoofers out there can actually be more efficient than your main speakers (this is fairly rare though).

Answering the question about setting speakers to small vs. large and how hard your reciever is working, we need to think in terms of full bandwidth, not just single frequencies. It should be obvious that a 10W sine wave at 100Hz plus another 10W sine wave at 1000Hz require more than 10W out of a single amplifier. When we look at a full-range music signal, content is spread across the entire range. It makes perfect sense that diverting 20% of the range to another box, in this case the subwoofer, will require less power from the amp. Likewise, if we look at the content in these two octaves (20-80Hz), we see large peaks which can drive the full range amp into clipping when big bass hits come along. diverting the bass energy isolates the main speakers and only your subwoofer will be overdriven by big 25Hz peaks.

Incedentally, many would probably be surprised to find that the highest average content in most music is in the midrange. The bass range tends to have somewhat lower average level with greater peaks, and the highest frequencies tend to have the lowest average level, yet some of the highest peak levels. In many cases you could argue that the biggest benefit of setting speakers to small comes from bringing back proper headroom to better handle the demanding mid and midbass range.

 

[Music Alchemist]

Here are some posts relevant to the power requirements of bass boosts with the JVC HA-SZ2000:
 

Originally Posted by Hawaiibadboy /img/forum/go_quote.gif
 
Quote:

  I asked Schiit Audio about how the Fulla would perform with the JVC HA-SZ2000 and was told that "It won't even get close to the Fulla's maximum output." And also that for a given loudness level, a less powerful and more powerful amp will output the same power into the headphones. So having, say, 600 mW (FiiO E12) instead of 250 mW (Schiit Fulla) would make no audible difference. In other words, there's no reason to get a more expensive/powerful amp unless it has certain features you want.

 
Maximum Power:
16 ohms: 250mW RMS per channel
32 ohms: 200mW RMS per channel
50 ohms: 175mW RMS per channel
300 ohms: 40mW RMS per channel
THD: <0.004%, 20Hz-20KHz, at 1V RMS
IMD: <0.005%, CCIR
SNR: >101db, A-weighted, referenced to 1V RMS
Crosstalk: >-67dB, 20 Hz-20KHz
Output Impedance: Less than 0.4 ohms
Gain: 1.5 (3.5db)
 
an e12 with a +16 dB switch on and bass boost I can turn it up a touch past half way.
 

 "It won't even get close to the Fulla's maximum output."

 
That sounds like you need less than 1/2....with much less power provided. I'm leery of that kind of feedback from pro's.
 
We are talking about bass and a set with a dual chambered passive crossed over dual driver config. It's kinda unique. That quote might wokr for some Dt770 but the SZ are a pain in the  ass/unique/ bass head dream set.
 
The #'s concern the basshead in me but maybe a person with the e18 can pipe in

  The Fiio X3 can power my K612 which is fairly power hungry, so I've no doubt the Fulla should be able to power the SZ2000 but you might not be able to boost its bass dramatically. Every 3 decibels you boost it'll require 2x as much power relatively. The X3 can't handle much more than a 5 decibel boost on my K612 without sound overly flabby, whereas I can easily boost 9 decibels on my Magni 2 Uber and maintain relatively good SQ (boosting will introduces quality issues to a degree regardless of whether or not there's overhead power)

  http://geoffthegreygeek.com/amplifier-power/ it takes 2x the energy to changed the decibels by 3.

Doubling the perceived loudness requires 10x more power, whereas 3 decibels is twice as much power. You can look this up, it's very objectively fact and there's additional factors with bass since it requires more power by default to compete with our natural hearing curve which is less sensitive the lower you go.

 

[stv014]

  Read what I said before. Even at higher than comfortable volume levels from the computer (which can only be done on some songs), the bass was noticeably weaker than with the amp at much lower volume levels, and all other volume levels as well. When it's that obvious, controlled testing is unnecessary unless I'm trying to prove something.

 
If there is any real loss of bass that is not due to volume differences or expectation bias, then it can easily be proven with a splitter and RMAA. Run the test with and without the headphones connected. If the headphone load causes a mid-bass boost (with full size dynamic models), then the output impedance is too high. If it results in a bass roll-off, then the problem is caused by capacitor coupling. With more detailed testing, the serial R and/or C can be calculated, and if the values are not reasonable for a headphone output, then it may in fact be configured as a line output. Also, if a loopback recording of a full scale tone at the same volume setting that you consider loud enough for music listening is clipped, then the maximum power output is indeed insufficient.

 

[Ruben123]

I also guess the comparison with a decent subwoofer is bad, because a sub is apart from the speaker. If you see your (double speakered) headphone as speaker system, I think you have to see the two separate speakers in your headphone as separate speakers in one loudspeaker box. Not as a separate subwoofer.
 
Which means that if you turn up the volume of a powerful amp, the power to the left side will increase. Not only the sub of the left earpiece, but both speakers in your headphone's left. Unless there is some intelligent crossover board in your headphone which decides where the power goes to. (or like the Beats I though which pump up the bass with a battery which houses in your HP)

 

[cel4145]

I also guess the comparison with a decent subwoofer is bad, because a sub is apart from the speaker.

Yeah. That post I sent him wasn't about headphones. I think we need to teach Music Alchemist how to provide better context for other information he provides, instead of just throwing up text from elsewhere

I cited specifically one line

"It should be obvious that a 10W sine wave at 100Hz plus another 10W sine wave at 1000Hz require more than 10W out of a single amplifier."

Just to provide evidence to him that additional bass content might push an amp into losing dynamics. So if you listen to classic rock, which is often doesn't have much lower midbass or subbass content, a headphone might be driven fine. If you listen to EDM (or movie content) that adds in a lot of sub bass content in addition to the mids and highs, then the amp might be losing dynamics or even clipping at heavy peaks.

 

[Music Alchemist]

  If there is any real loss of bass that is not due to volume differences or expectation bias, then it can easily be proven with a splitter and RMAA. Run the test with and without the headphones connected. If the headphone load causes a mid-bass boost (with full size dynamic models), then the output impedance is too high. If it results in a bass roll-off, then the problem is caused by capacitor coupling. With more detailed testing, the serial R and/or C can be calculated, and if the values are not reasonable for a headphone output, then it may in fact be configured as a line output. Also, if a loopback recording of a full scale tone at the same volume setting that you consider loud enough for music listening is clipped, then the maximum power output is indeed insufficient.

 
Thanks for the info. Next time I have amps around and experience this phenomenon again, I may try it out.
 

  I also guess the comparison with a decent subwoofer is bad, because a sub is apart from the speaker. If you see your (double speakered) headphone as speaker system, I think you have to see the two separate speakers in your headphone as separate speakers in one loudspeaker box. Not as a separate subwoofer.
 
Which means that if you turn up the volume of a powerful amp, the power to the left side will increase. Not only the sub of the left earpiece, but both speakers in your headphone's left. Unless there is some intelligent crossover board in your headphone which decides where the power goes to. (or like the Beats I though which pump up the bass with a battery which houses in your HP)

 
If you turn up the volume, all four drivers would obviously get louder. Not sure what your point was.
 

Yeah. That post I sent him wasn't about headphones. I think we need to teach Music Alchemist how to provide better context for other information he provides, instead of just throwing up text from elsewhere

I cited specifically one line

"It should be obvious that a 10W sine wave at 100Hz plus another 10W sine wave at 1000Hz require more than 10W out of a single amplifier."

Just to provide evidence to him that additional bass content might push an amp into losing dynamics. So if you listen to classic rock, which is often doesn't have much lower midbass or subbass content, a headphone might be driven fine. If you listen to EDM (or movie content) that adds in a lot of sub bass content in addition to the mids and highs, then the amp might be losing dynamics or even clipping at heavy peaks.

 
I tried providing context!  :'( lol

 

[stv014]

  Thanks for the info. Next time I have amps around and experience this phenomenon again, I may try it out.

 
You do not need the amps to test the laptop, if you still have it.

 

[Ruben123]

Well Music Alchemist said that bass (subwoofer) needs more power than mid and high ranges (in normal speakers), but that is invalid here. A headphone most of the time has only one speaker per side, so power=volume.

 

[cjl]

   
If you're saying that it can improve the sound quality of the transient peaks (even when with less power, it can still achieve the same volume level, except distorted peaks, etc.), then I agree with you; it's just that sometimes it's not clear how much power a headphone really needs. For example, one of the most common things I hear about the HE-6 is that it can sound downright awful from some amps that "should" have enough power.
 
Since you're knowledgeable about these things, would you be able to tell me how much power the JVC HA-SZ2000 would need? (Not just for normal listening, but for the boosted bass and potentially higher volumes that most owners use. Also bear in mind that it has four drivers instead of two.)
 

The JVC specifies a sensitivity of 108dB @ 1mW. They have an impedance of 16 ohms. If you want enough headroom to go to 120dB cleanly on transients (which should be way more than enough), you'll need 16mW. To attain 16mW into 16 ohms, you'll need around a half a volt of signal amplitude. This is all pretty trivial for any modern amp. The one potential issue is that with two drivers and a crossover, chances are the impedance curve of the HA-SZ2000 isn't very flat, and this means that it should be driven by an amp with an output impedance much lower than the headphone impedance to avoid issues with damping factor or frequency response. Ideally, you'd want your amp to have an output impedance of <1 ohm or so for these headphones, and this is where a lot of sound cards and devices have the opportunity to fall flat. As long as your amp has a low output impedance though, all the other specs should be really easy to attain. 16mW and half a volt is not a difficult thing to achieve.
 
For example, an O2 can push a little over 250mW and around 2V into a 15 ohm load. This would be enough to cleanly drive them to 132dB, which would promptly damage your hearing and/or blow the headphones.
 
As for the HE-6, it's an astonishingly bad headphone at transferring electrical energy into sound. It is incredibly inefficient, and as such, requires a lot of power to drive it. It is one of the few headphones where you really would need to be careful selecting an amp for it, since finding a good, low output impedance, low distortion, high power amp could be a challenge (and it could require several watts, if I remember the numbers right). It's very much an outlier though.