[CactusPete23]

The output impedance affects the amps ability to control the speaker drivers frequency response. Say a speaker has a peak of 2db at 50 hz. A higher output impedance might allow that that 50hz peak to bump up to +3 or 4db. All dynamic speakers have multiple dips and peaks. Look at a frequency response graph. So an IEM's sound signature could vary from low to high output impedance DAPs. Sometimes the sound is subjectively worse, but sometimes it can be an improvement. Multi drivers and crossovers also are harder to drive.

Now the disadvantage of low output impedance. To get low output impedance down in the 1 ohm range the amp has to use negative feedback. Negative feedback can make the amp sound unnatural. Ayre Acoustics hates negative feedback. So the PonoPlayer has none. This means an output impedance of ~ 3.1 ohms single ended or ~6.2 balanced. But every earphone I have compared, including the Trinity Atlas, sounds better balanced. To be fair this might back fire with some of those 8 driver per ear 8 ohm IEMs. I am actually interested in Hidiz now.

Great, Thanks for the explanation ! I did not realize feedback control was needed for low impedance output. Guess Many DAPs with 1 and 2 OHM Impedance, like OPUS1, do that,?
Any idea what the 32 ohm "loaded" output impedance means?

Yes, I'm trying to do what I can with Specifications on the Hidizs AP200, since there are no reviews of the audio available yet.

Also wondering if higher output impedance might also be why some IEMs sound changes on different DAPs ?

Sorry for hijacking this thread with a tech question.

 

[OldDude04]

You didn't hijack the thread with a tech question, this is the stuff I started this thread for. An open place to discuss all these things related to IEMs and Ear Buds. I'm learning from your questions and their answers.

 

[barondla]

CactusPete23, yes big changes of output impedance will affect the sound of the same earphone on different players. All dynamic drivers have peaks and dips. Planars have much, much less impedance variations and are less affected by output impedance. Dynamic speakers can have their impedance flattened by using a zobel network. This is fairly common in speakers. Not sure about earphones. Electrostats have amazingly low impedance. Transistor amps tend to blow up at less than 1 ohm. So electrostats almost always have matching transformers, special amps, or both. Done correctly this makes them easy to drive and flattens their impedance. The M&J headphones have 1 dynamic, 1 electret driver plus a transformer and a crossover in each earpiece.

Usually electronics have to be tested into a load. Perhaps that is what the 32 ohm loaded means. Basically a 32 ohm resistor. Don't know for sure.

 

[majo123]

You didn't hijack the thread with a tech question, this is the stuff I started this thread for. An open place to discuss all these things related to IEMs and Ear Buds. I'm learning from your questions and their answers.

Me too ,im definitely still learning.
it is a good place to ask anything don't think there's another thread like it.
The one thing I like is no one is going to complain about asking/talking about a rival product if we think it's better.
As long as we stick to headfi rules and no one starts getting upset because they disagree on which Is better or right then This thread will be pretty cool as it evolves.
Also if on another thread and someone wants to talk about another product in more detail then we can just say meet here.

 

[majo123]

Here is where one place saw the 1/8 rule.... with some explanation... http://nwavguy.blogspot.com/2011/02/headphone-amp-impedance.html

Me too ,im definitely still learning.
it is a good place to ask anything don't think there's another thread like it.
The one thing I like is no one is going to complain about asking/talking about a rival product if we think it's better.
As long as we stick to headfi rules and no one starts getting upset because they disagree on which Is better or right then This thread will be pretty cool as it evolves.
Also if on another thread and someone wants to talk about another product in more detail then we can just say meet here.

I just read the 1/8th rule it was pretty interesting and as I said not something i have come across or ever considered, I have always mostly just bought iems or headphones that were generally just considered easy to drive...except for the planars which are not realy designed for portable anyway.

 

[AverageDude]

Speaking of DAPs, I currently run my FiiO X5ii stacked with a FiiO A5 amp. This combo gives me the greatest satisfaction and allows me to run all of my IEMs, my 320 Ω Zen 2.0 as well as my unefficient (but delightful in my ears) AKG K701 and K7xx.
With FiiO's latest announcement, I am considering getting a X7ii, but I am not certain of the amp I should be getting. I guess there is no amp that would be an all-rounder like the A5 is, and should therefore get an "IEM type AM1" module, as well as another, more powerful one (AM2A?), to get the best out of the player. Am I correct in my assumption?
Another path I could go by would be getting the AM3 balanced amp module, as it seems to have both a 2.5 balanced output as well as a 3.5 straight output.
Could anyone with an experience with the X7 chime in?
Anyway, the X7ii is not yet released, so my interest is still in its early stage.

 

[majo123]

Speaking of DAPs, I currently run my FiiO X5ii stacked with a FiiO A5 amp. This combo gives me the greatest satisfaction and allows me to run all of my IEMs, my 320 Ω Zen 2.0 as well as my unefficient (but delightful in my ears) AKG K701 and K7xx.
With FiiO's latest announcement, I am considering getting a X7ii, but I am not certain of the amp I should be getting. I guess there is no amp that would be an all-rounder like the A5 is, and should therefore get an "IEM type AM1" module, as well as another, more powerful one (AM2A?), to get the best out of the player. Am I correct in my assumption?
Another path I could go by would be getting the AM3 balanced amp module, as it seems to have both a 2.5 balanced output as well as a 3.5 straight output.
Could anyone with an experience with the X7 chime in?
Anyway, the X7ii is not yet released, so my interest is still in its early stage.

I have a fiio x7 with am1 am2 am3..i hsve not read much yet on the x7ll first a question for you is it the same dac chip as an x7 ?.
My experience with all 3 modules is .
Am1.... nice detail retrieval but not much body to the sound and only powerful enough for iems.
Am2 ...slightly less analytical but more body warmer sound.
Am3 ..like am1 but with the body of am2 but i find the highs a bit to much on standard 3.5mm bit better in balanced.
If I were to chose it would be a toss up, very close between am2 and am3, I like am2 better control on the highs but the detail retrieval on am3 is great.
Personally I used am3 and lived with the slight sibilance on the highs . But an allrounder definitely am2.
I am currently selling my x7 with modules if anyone in the UK is interested.

 

[OldDude04]

Me too ,im definitely still learning.
it is a good place to ask anything don't think there's another thread like it.
The one thing I like is no one is going to complain about asking/talking about a rival product if we think it's better.
As long as we stick to headfi rules and no one starts getting upset because they disagree on which Is better or right then This thread will be pretty cool as it evolves.
Also if on another thread and someone wants to talk about another product in more detail then we can just say meet here.

Exactly, well said.

 

[Duncan]

I wonder if anyone has an old school Sony MDR-E484, or an even harder to find E282 that they don't want anymore

 

[Miko 7]

Hi, Love the idea behind this thread!

This seems to be a safe place to ask what may be a stupid question... And I am pretty ignorant when it comes to Audio Electronics Theory, etc...

But I was looking at a DAP on Kickstarter, the AP200. It listed 2 Output Impedance levels. 4.8 Ohm, and then it said (32 Ohm Loaded).

Can any of you help me understand what the "32 Ohm loaded" means?

- The 4.8 Ohm impedance already has me worried because I have heard of the 1/8 rule, where the output impedance of an amp should be 1/8 the impedance of an IEM/Headphone to reduce risk of coloring the sound.... Meaning IEMs should have 8 X 3.2 or higher than around 24 Ohm impedance for lowest risk of problems.
- And 32 Ohms would mean all my IEMs would be way out of that range, as none are over 250 Ohms to match the 1/8 rule; Heck the DAP says it's for headphones from 16 to 150 Ohm...
So something tells me that the "loaded" impedance shouldn't be used with the 1/8 rule.

Thanks for any ideas !

It has to refer to 4.8Ω min and 32Ω max impedance of the amp itself. When you plug in your headphones you close the circuit, hence why if your headphones are < 4.8Ω your source won't provide enough current and the sound will be distorted, and if your heaphones are > 32Ω your source won't supply enough voltage and the sound will clip. Assuming you use a simplified diagram using Thev. or Norton eq. you can do the math fairly easy.

As far as the amp coloring the sound, as long as you are not close to the min or max values it shouldn't be much difference. Your amp is ideally a wire with gain to boost the signal from your dac so all you should hear is and unadulterated signature of your dac

If you PM me your email I can send you a current text book and instructors manual on circuit analysis techniques. It starts from the very basics such as: ohm law kvl kcl nodal + mesh nalysis, Nroton + thevenin eq , test current, test voltage, and goes through op-amps, impedence eq and sinusoidal steady state. You don't have to replicate all the math flawlessly, but you should walk away with excellent logic and understanding of your hobby, and the logic here is really what matters and can be the hardest part to grasp.

 

[Miko 7]

Having said that I assume your eighth rule should use the impedence load of your headphone wrt max impedence load of your amp as those are the numbers that would be used in the test circuit if you're using dynamic drivers

or something

 

[CactusPete23]

Back to IEMs... I know that LG is not especially noted for making IEMs... But I recently acquired a Hong Kong Version of the LG-G6 and was enjoying the audio quality with it's Quad DAC design... Anyway, after two months found a pair of LG earphones included in the package. They have a mic, and are tiny. Anyway, I tried them and thought they sounded pretty good. Better across the range than most of the poor quality IEMs you get with a phone. Though not marked, I believe they are the LG Quadbeat 3. They can be had for $12 to $25 on ebay... But while searching for a name of the headphones, I found that LG just introduced the Quadbeat4 that is supposed to have cleaner highs, And highs were probably the weakest part of the Quadbeat3's. Quadbeat4's are around $50 a pair now, but should drop to Below $30 when they are out a few months. Have not seen a review I can read (or been able to google translate) of the QB4s yet, but they are on my "look out" list. The Quadbeats have a single multilayer diaphragm that is supposed to be in-house developed by LG. Supposedly the earlier QB1 and 2 are not so good.
Anyway, might be worth a try, and not a crime if they break.

 

[majo123]

Following on from the trinity thread about the new flares pro, ( if anyone is reading) I am so close to buying these this week , as was said the only thing that's stopping me is lack of info, but the info that is out there is very positive apart from the audiophile foam tips which are apparently the best being like paper.
Build quality looks good too.

 

[ezekiel77]

Between the lyra and the Jupiter, which one should I splurge on?

Jupiter sounds better but fits worse. Lyra has a more ergonomic shell but sounds closed-in and unnatural next to the Jupiter.

Jupiter (and Nova and Andromeda) wouldn't get my recommendation because the inner corners press onto my ears, making them uncomfortable and nearly painful at the hour mark. Many others don't have the fit issue though, best you try them first. Pity... I loved the sound.

 

[tjw321]

Following on from the trinity thread about the new flares pro, ( if anyone is reading) I am so close to buying these this week , as was said the only thing that's stopping me is lack of info, but the info that is out there is very positive apart from the audiophile foam tips which are apparently the best being like paper.
Build quality looks good too.

I bought the flares a few weeks back and haven't listened to anything else since. They are incredibly sensitive to fit, though. A lot of people say they are sensitive to the tips, but in my experience it is the fit that is more important. I get good results from Trinity hybrids, spinfits and the included silicon tips (I can't be bothered with foams, either). In my case, I need the smallest size in each, and the insertion has to be pretty deep. I haven't managed to get spiral dots quite there yet, but I don't have any of those small enough for my (tiny) ear-canals. There is some sensitivity to the tips, as well, but nothing out of the ordinary for me, with any that I have got a decent fit from.
I nearly didn't buy them because I had no use for the bluetooth dongle but I've ended up using it quite a lot. It was much better than i expected, and the dongle is much less of a tether than my dap.