Have I been lied to my whole life?
May 28, 2015 at 1:35 AM Thread Starter Post #1 of 7

wafflezz

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I've always been lead to believe that you need a super amp to power headphones that are 300 ohms and above. Namely the hd600/650, akg 701, beyer dt880, etc.
...but my friends recently stopped by to chill and wanted to use my headphones(hd650). I said sure...but they wanted to plug them into an iphone. I laughed and said they'll barely produce noise.
 
Low and behold
 
They actually worked
 
They sounded terrible(to me) but heck, they were at a pretty decent volume and I don't even think the iphone was cranking full power. Also at the same time, I haven't heard those songs before so i don't really know if they would sound better on my set up or if the distortion and booming bass is really just a part of the song itself.
 
 
Why are we encouraging people to buy big amps and tubes again? I'm starting to suspect top end stuff is grossly overpowered for most dynamic drivers
 
May 28, 2015 at 1:48 AM Post #2 of 7

ToddTheMetalGod

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The reason that it sounds bad is probably mostly due to being underpowered. The first time I heard the HD650 was out of an iPod unamped and I hated them, but amped they're one of my favourite headphones. Just because it produces sound, doesn't mean it is powered properly. The HD650's impedence curve goes up to 600 ohms in the bass region if I recall, which would probably best be dealt with by a decent amp.

You have to remember that people greatly exaggerate the required power in audio. Many, many people confuse the quality of power with quantity (mostly because high end amps usually have more power). I suggest using a power calculator like at audiobot9000.com , it can give you fairly accurate SPL estimates for peak SPL. Keep in mind that it is peak and you need to compensate slightly for the dynamic range of the music.
 
May 28, 2015 at 1:49 AM Post #3 of 7

TMRaven

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It's a combination of:
 
1. being a hobby, we like to continue our audio journey and buy more and more expensive things, never being satisfied
2. people largely overstate differences in sound quality that 'better' upstream equipment brings, so lots of readers will buy based off those overstatements
3. old myths that are still parroted to this day. things like more power = more quality etc.  a lot of entry level stuff like an iPhone or iPod these days will power even the more power-hungry headphones just fine, and with good sound quality.  It's only when you start trying to power relatively inefficient headphones using music with very high dynamic range that you run out of headroom.  For what it's worth, I haven't found a headphone that sounds terrible out of my 2014 macbook air or 2009 iMac-- and that includes the infamous HD800 and its supposed amp pickiness. 
 
May 28, 2015 at 2:04 AM Post #4 of 7

Music Alchemist

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You have to remember that people greatly exaggerate the required power in audio. Many, many people confuse the quality of power with quantity (mostly because high end amps usually have more power). I suggest using a power calculator like at audiobot9000.com , it can give you fairly accurate SPL estimates for peak SPL. Keep in mind that it is peak and you need to compensate slightly for the dynamic range of the music.

 
Much of the data on that site is very incorrect. I suggest calculating the power requirements of headphones manually, via the calculator at this resource: http://www.apexhifi.com/specs.html
 
May 28, 2015 at 12:09 PM Post #6 of 7

ProtegeManiac

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...but my friends recently stopped by to chill and wanted to use my headphones(hd650). I said sure...but they wanted to plug them into an iphone. I laughed and said they'll barely produce noise.
 
Lo and behold
 
They actually worked
----
Why are we encouraging people to buy big amps and tubes again? I'm starting to suspect top end stuff is grossly overpowered for most dynamic drivers

 
1. It depends on the device. My HD600 works well enough out of an iPad and SGS3 but it was unusable on my iPod 5g. Given an audiophile who is not susceptible to viral infections like upgraditis and SARS (severe audio replacement syndrome) will still at some point replace his smartphone, then having an amp (and a way to get a clean line signal into it) guarantees that fatally dropping one's phone will not result in being restricted to picking a phone based purely on SQ. In any case, I always use amps when practical, but any device I buy gets used with all headphones and IEMs at some point (like a power outtage, but I usually did it before then so I'd know what to use when I'm bored and dependent on batteries).
 
2. In the same manner that some people are tone-deaf (or can't hear spatial cues properly), the opposite spectrum we have people who are hearing things based on psychological predisposition. If not that, they're just not aware of hearing damage - sure, it can be true that this amp makes this headphone go really loud with no audible distortion, he's listening at 92db and the amp it's comparing it to can take that same headphone to 88db with no distortion either. That's still better than how his smartphone might already have 5% THD when driving that headphone at 85db and is still safe for listening to a whole album with. In some cases it's not even that the lack of distortion at higher volumes, but that people aren't aware of how much ambient noise there is just because there isn't a distinct sound, and by playing louder (without getting more distortion) all he's doing really is overcoming the noise floor, which can otherwise be done by using closed back headphones or listening at night with the windows closed.
 
  I've always been lead to believe that you need a super amp to power headphones that are 300 ohms and above. Namely the hd600/650, akg 701, beyer dt880, etc.

 
A decent, clean amplifier for not a lot of money works fine. The Corda Headfive and Schiit Asgard work fine even for some orthos; no need to get a headphone amp larger than a Class A/B speaker amp.
 
Quote:
 
They sounded terrible(to me) but heck, they were at a pretty decent volume and I don't even think the iphone was cranking full power. Also at the same time, I haven't heard those songs before so i don't really know if they would sound better on my set up or if the distortion and booming bass is really just a part of the song itself.

 
It would be best if you listen to the same tracks at the same bitrate on your system and get a more definite answer. That could be distortion from the iPhone - 300ohms is still a stiff load. Not even the efficiency of the T1 can get around the 600ohm load when using my iPad.
 
May 28, 2015 at 7:31 PM Post #7 of 7

jcx

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you need some basic electrical power and impedance info, those specs for your headphone and an appreciation of SPL, what's safe average levels for long term listening, what the peak values you might want to reproduce for few seconds per hour for real live performance dynamics
 
https://web.archive.org/web/20120320082351/http://gilmore2.chem.northwestern.edu/articles/hearing_art.htm can be a help
 
1 Vrms is a common DAP output Voltage - will drive 300 Ohm 98 dB/mW headphones just a little ofer 100 dB SPL - which is loud, in fact "loud enough" for even dynamically recorded material if you listen at "conversational" average SPL of <, ~80 dB
 
but 10 Vrms could be desired if you want to allow for a short treat of listening at live performance levels for high dynamic range Jazz or Orchestral music
 
 
the power and impedance relations are required because old school headphones are rated in dB SPL relative to a reference power level of 1 mWrms - which need the headphone Z to calc required amplifier output Voltage and Current
 

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