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Old 03-05-2013, 02:01 PM
neutral neutral is offline
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Default Help me learn about the basics (impedance, how to pair a player to set of earphones)

I mean, not how to plug them together but how to chose a pair that sounds good together.

And where to find some great introductory articles on what does different impedances of earhpones and players mean to sounds, different schools of soundscapes... best is just neutral, right?
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Old 03-05-2013, 02:03 PM
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http://nwavguy.blogspot.com/2011/02/...impedance.html
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Old 03-05-2013, 05:29 PM
neutral neutral is offline
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This seems like exactly what I was looking for. Will read later on my Kindle.
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Old 03-07-2013, 09:17 AM
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Quote:
Originally Posted by neutral View Post
I mean, not how to plug them together but how to chose a pair that sounds good together.
numbers wont tell you a lot about this. only to a limited extent. very limited in my opinion. impedance usualy only effects the volume level, not the tone or sound specifically.

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different schools of soundscapes... best is just neutral, right?
what sounds good to you is what is best. everybody has different tastes and different ears.
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Old 03-07-2013, 10:04 AM
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Originally Posted by IDvsEGO View Post
impedance usualy only effects the volume level, not the tone or sound specifically.
It can affect frequency response (thus, how it sounds) in wildly varying amounts, from "inaudible" to "wtf is this crap".
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Old 03-07-2013, 12:57 PM
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I could be mistaken but impedance would only effect the entire output level. meaning that if you had two sets with everything else the same and the exact same source but different impedances, they would sound the same once volume matched (assuming volume matching could be done without introducing distortion from the source). Its not like two identical sets at the same volume would have different bass response or something.

and volume matching means both have the same level of volume coming out of them. this often means that the source is set at different levels to achieve the same output volume. a lot of times people hear two sets and say that the louder one sounds better...or they dont have enough juice from their source to push the higher impedance set so when they jack the source up to full volume ranges the amp starts to distort and they say "man, these cans dont sound as good". its not the cans introducing the difference in sound. they are merely recreating what is sent to them. garbage in, garbage out. so I guess you could say that impedance can effect how they sound from your source. for a crappy analogy...if you are pushing a half empty cart of dirt up a hill and then an overflowing one your experience will be very different... but the dirt didnt change. You just cant push the really full one so it is kind of useless and stupid for you.

disclaimer - I am drawing a lot of these opinions from basic speaker principles as well as popular headphone opinions. when you get into home and car speaker configurations you start playing with impedance and manipualting it a lot more. Speakers that are exactly the same except for the impedance are pretty common so that you can wire multi speaker configs and not overload your source.

edit - I re-read you reply a couple of times and it is possible you are using frequency response when you mean volume...meaning we are saying the same thing. frequency response is typically a chart that shows what frequencies a speaker is capable of reproducing at a set volume level. it is not measured across the board of its output.

Last edited by IDvsEGO; 03-07-2013 at 01:03 PM.
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Old 03-08-2013, 05:17 AM
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No, I don't mean volume. High output impedance can cause frequency response variations. See:

Clip+ (0.5Ω) with my Shure SE425 IEMs:
http://outpost.fr/rmaa/Clip-Shure_SE425.htm

iPod Classic (5.5Ω) with the same IEMs:
http://outpost.fr/rmaa/iPod_Classic-Shure_SE425.htm

EMU 0204 USB (23Ω) with the same IEMs:
http://outpost.fr/rmaa/EMU_0204_USB-Shure_SE425.htm

My laptop's onboard audio (74Ω) with the same IEMs:
http://outpost.fr/rmaa/ALC663-Shure_SE425.htm

In those examples, you can see the mids and highs being emphasized in increasing amounts, as the output impedance increases. You'll get different results with different cans.

All of them have a flat frequency response, when unloaded:
http://outpost.fr/rmaa/Clip.htm
http://outpost.fr/rmaa/iPod_Classic.htm
http://outpost.fr/rmaa/EMU_0204_USB.htm
http://outpost.fr/rmaa/ALC663.htm

Last edited by skamp; 03-08-2013 at 05:23 AM.
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Old 03-27-2013, 10:09 PM
neutral neutral is offline
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Quote:
Originally Posted by skamp View Post
No, I don't mean volume. High output impedance can cause frequency response variations. See:

Clip+ (0.5Ω) with my Shure SE425 IEMs:
http://outpost.fr/rmaa/Clip-Shure_SE425.htm

iPod Classic (5.5Ω) with the same IEMs:
http://outpost.fr/rmaa/iPod_Classic-Shure_SE425.htm
Maybe I don't quite get it but 1st, how do you measure the players with the output connected? I understand you you can measure them unloaded.

Also, what is worthy to see between the Clip+'s (0.5Ω) and the iPod's (5.5Ω?) graphs?
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Old 03-28-2013, 03:17 AM
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Quote:
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Maybe I don't quite get it but 1st, how do you measure the players with the output connected? I understand you you can measure them unloaded.
To measure an output unloaded, connect the output to the input of your sound card, and record the RMAA test signal.

To measure an output loaded with headphones, do the same, except with a stereo splitter cable connected to the output, with one end connected to your sound card's input, and the other end connected to your headphones.

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Also, what is worthy to see between the Clip+'s (0.5Ω) and the iPod's (5.5Ω?) graphs?
Look at the frequency response graph (the first one on the page). The FR on the Clip+ when loaded with my Shures is ruler flat, meaning that the device is producing sound exactly like it should.

The FR graph on the iPod Classic when loaded with the same IEMs, is not flat, it suffers from some amount of variation, meaning that it's not producing sound the way it should. That's the effect of highish output impedance, and non-flat impedance IEMs, combined. That effect varies with the headphones / IEMs that you attach to a high output impedance source. Some will be affected more or less wildly, some will not (flat impedance headphones).

The FR will always be flat, with low impedance outputs like a Clip+ or an iPod Touch 5. FR variations will be (much) worse with higher output impedance sources like Hifiman DAPs (~30Ω), and / or with more quirky headphones / IEMs (like the Ultimate Ears Triple Fi 10).
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Old 03-08-2013, 05:28 AM
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Did you read the link to NwAvGuy's blog?

Quote:
Headphone impedance changes with frequency. If the output impedance is much above zero this means the voltage delivered to the headphones will also change with frequency. The greater the output impedance, the greater the frequency response deviations. Different headphones will interact in different, and typically unpredictable, ways with the source. Sometimes these variations can be large and plainly audible.
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  #11  
Old 03-08-2013, 08:39 AM
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Both of your bits are referring to source impedance which isnt at all what I was talking aobut. And yes, any clean, unloaded source will be the same when it hasnt encountered resistance yet. That's why I specified same source. OP didnt though so your information is relavant to his question. I just oversimplified the scenario assuming a same source when picking headphones.

the quote from NwAvGuy is exactly why I dont put much weight on the headphone ratings unless they are extreme. the single impedance rating doesn't reflect the amount of variation from one unit to the next or with other variables on the same unit. none of these stats are constant or in a vacuum and there are not any serious guidelines for manufacturers to report them. The numbers put on the package could be unattainable except under the specific lab conditions that they were tested and are hardly consistent in the lower end stuff. That is one of the less tangible advantages that high end items get you. In car audio there are testing guidelines because of the competition aspect so I pay attention to those. with headphones I put way more on user impressions and what my ears hear.
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  #12  
Old 03-08-2013, 01:40 PM
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Quote:
Originally Posted by IDvsEGO View Post
I could be mistaken but impedance would only effect the entire output level.
You are mistaken. If the output impedance is any other value then zero, the load impedance will impact the frequency response and distortion.

Quote:
Originally Posted by IDvsEGO View Post
Both of your bits are referring to source impedance which isnt at all what I was talking aobut.
The first is about output impedance, the second load impedance. Read both of them.
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  #13  
Old 03-08-2013, 10:15 AM
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The impedance curve of the headphones doesn't matter if you choose a low output impedance source, like a Clip+ or an iPod Touch 5, or if the minimum impedance of the headphones is high enough (Zhp > Zout * 8).

If you want to find out the impedance curve of your headphones, you might find them there: http://www.headphone.com/learning-ce...ld-a-graph.php
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Old 03-08-2013, 10:47 AM
skip252 skip252 is offline
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You need to define extreme for it to have any relevance. I don't think you can just disregard a headphones rated impedance because there might be some variation from the stated rating. A set of IEMs that are rated at 16 ohms are not going to present to an amp anywhere near like a set of full size cans rated at 80 ohms.

I've seen enough unrealistic manufacturers ratings on SPL and frequency response range that I don't have much faith in those. However if maker says a set of cans is 32 ohms that should be close enough that a variation of a few ohms one way or the other won't make enough of a difference when deciding if they should work with a portable source.
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  #15  
Old 03-09-2013, 02:20 AM
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Some examples of headphones / IEMs with non-flat impedance curves (i.e. headphones that would be affected by devices whose output impedance is too high):

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  #16  
Old 03-27-2013, 11:07 PM
neutral neutral is offline
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Should I chose the earpiece to the player or vica versa? Or the two together?
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