[thornygravy]

So I got my new Triple.fi's about a week ago, and I noticed that when I played them out of my laptop vs my portable rig, that the laptop sounded more pleasing to me. I noticed that my ipod/lod/ibasso t4 sounded very harsh in the highs and lacking a bit in the bass area.
 
I bought this 32 ohm resistor adapter on ebay to try to eliminate some of the hiss that my T4 produced. The adapter removed the hiss but to my surprise the sound produced was much more pleasing. A bit more bass and the highs aren't as sharp. Is this supposed to happen?

 

[thornygravy]

Lovin all the responses.

 

[Photofan1986]

I cannot say for the Triple fi, but I noticed with my multi armature based IEMS (SF5pro before and now SM3) that they react to impedance adapter. In my experience, I lose lots of clarity and treble, but maybe that's what you're after.
I believe that the filter inside the iem (I mean the crossover, not the mechanical damper) reacts as a band-pass filter when associated with some resistor or ouput. For instance, my DAC Musiland SVDAC05 has a fantastic sound with all my dynamic iems and my single armature based iems, but it does not sound good at all with my multi-armature based iems.
 
Quite a mystery for me, though.

 

[thornygravy]

Yea, the highs are definitely lessened, which on some phones IMO would be bad, but I find the UE series to be a bit harsh in the highs, at least with my portable rig it was. Perhaps the T4 is a bright amp? I don't really know.

 

[Pangaea]

I use one consistently with my Grados and Headroom Desktop Amp.  A much more robust sound and better bass.  If you are using a setup that has more than enough power for your HPs, I think a resistor (if decent quality) will mostly improve the sound.
 
I have also had success with the ER4Ps, but that is a lot more documented.

 

[mark2410]

yes adding impedance can really make a huge difference to things with crossovers.  single drivered things all improve with more impedance (some tiny some a lot) but things with crossovers can be very variable and radically change the sound. 
 
oh and btw the TF10 is not harsh in the highs at all.  it is however highly abundant and crisp and that can be unpleasnt after a while but that is not the same as harsh.

 

[mrspeakers]

Quote:

yes adding impedance can really make a huge difference to things with crossovers.  single drivered things all improve with more impedance (some tiny some a lot) but things with crossovers can be very variable and radically change the sound. 
 
oh and btw the TF10 is not harsh in the highs at all.  it is however highly abundant and crisp and that can be unpleasnt after a while but that is not the same as harsh.

This is not a correct statement...  
 
Yes, adding impedance can alter the frequency response of devices with crossovers, but it also will alter the frequency response of any device that does not have an ideal ruler-flat impedance.  All dynamic drivers have bumps in the impedance curve, and I think balanced armatures do, as well.  The only very/pretty flat curves I've seen for impedance are some orthodynamic or electrostatic drivers.
 
Regarding "single drivered thinks improving with more impedance," what is the science behind that?  The higher the output impedance, the less like an ideal current or voltage source the amp is, and particularly if you have low Z loads, like IEMs, or 32 ohm phones, a high Z amp will distinctly color the sound if, per the above, their impedance is not flat.
 
In general, a higher output impedance will only be reasonable if you have high impedance phones, and even then, the greater the ratio of the phone impedance to amp impedance, the lower the potential coloration. 
 

 

[mrspeakers]

Quote:

I use one consistently with my Grados and Headroom Desktop Amp.  A much more robust sound and better bass.  If you are using a setup that has more than enough power for your HPs, I think a resistor (if decent quality) will mostly improve the sound.
 
I have also had success with the ER4Ps, but that is a lot more documented.

Per my previous note, this article by Tom does a great job in non-technical terms to explain why this is.  In fact, the higher impedance is effectively boosting certain frequencies of your phone because of the fact that the Grado's impedance is not ruler flat.  IMHO, this is just a tone control, with very little control.   It's also dissipating power from your amp as waste heat, so you have to have a bigger amp for a given volume level.  
 
http://www.avguide.com/blog/why-headphone-amps-sound-different-frequency-responseimpedance-issues
 
My $.02, if you think your phones need more bass, buy different phones or EQ.  Don't solve the problem randomly with impedance.
 

 

[mark2410]

the science is my ears.
 
never have i come across a single drivered earphone that has not improved by adding impedance.  they may exist (and so may unicorns, i cant prove they dont) but all empirical evidence i have available draws me to make that conclusion.

 

[mrspeakers]

If you are a bass-head, that'd make sense.  But if you read the link in my prior post, you'll see why.  

This is just a funky way to EQ a 'phone, and instead of having actual control over the final results, you are totally dependent on the impedance curve, which most people will never actually see.  Seriously, digital or analog EQ will allow you more precise control over tone if you don't like the default sound of your phones...

 

[mrspeakers]

All my amps, portable or home, are <10 ohms out because otherwise I hear the shift in bass and the decrease in clarity.  
 
Here's another interesting technical note on this from Wikipedia;
 
 

Output Impedance

Many headphone amplifiers have an output impedance in the range of 20 - 50 Ohms. The 1996 IEC 61938 standard recommended an output impedance of 120 Ohms. The standard included a note that "For most types of headphones, the source impedance has very little effect on the performance." In 2008 Stereophile published an article that showed that a 120-Ohm output impedance could cause a 5-dB error in frequency response with certain headphones. ^[1] The article concludes that the effect of output impedance on frequency response is "non-trivial". Some newer headphone amplifiers have output impedances that are less than one Ohm. [1]

Low output impedance can also reduce distortion by improving the control that the source has over just where the transducer is in space. This is often expressed as damping factor. For example, a 32 Ω headphone driven by a popular DIY headphone amp with a <1 Ω output impedance (the Gilmore Dynamic) would have a damping factor of >32, whereas the same headphone driven with an iPod (5 Ω output impedance) would have a damping factor of just 6.4. If the 120 ohms recommendation is applied, the damping factor would be 0.26.

Of course, output impedance is not the only specification relevant to choosing a headphone amplifier — THD, frequency response, IMD, output power, minimum load impedance, and other measurements are also significant.

 

[mark2410]

have you tried it?

 

[mrspeakers]

Yes, and really don't like it at all.  Boomy and loose sounding.

 

[Pangaea]

Quote:

Quote:

I use one consistently with my Grados and Headroom Desktop Amp.  A much more robust sound and better bass.  If you are using a setup that has more than enough power for your HPs, I think a resistor (if decent quality) will mostly improve the sound.
 
I have also had success with the ER4Ps, but that is a lot more documented.

Per my previous note, this article by Tom does a great job in non-technical terms to explain why this is.  In fact, the higher impedance is effectively boosting certain frequencies of your phone because of the fact that the Grado's impedance is not ruler flat.  IMHO, this is just a tone control, with very little control.   It's also dissipating power from your amp as waste heat, so you have to have a bigger amp for a given volume level.  
 
http://www.avguide.com/blog/why-headphone-amps-sound-different-frequency-responseimpedance-issues
 
My $.02, if you think your phones need more bass, buy different phones or EQ.  Don't solve the problem randomly with impedance.
 

Your last sentence makes me laugh.  Mostly because you didn't listen to anything I said and then just put your own spin on it.  All I will add is that nothing was done randomly (EQing is a much more random practice), it was quite deliberate and I have used the setup for a couple years.  It is very easy to A - B it, and I like the sound much better with the adaptor.  And to be clear, I said better not more.  

 

[mrspeakers]

Actually, I did, but it appears you didn't understand my point.  What you did is trial and error to get a result you like, and working this way is valid.  
 
The limit of your approach is the ability to modify the signal is entirely dependent on one thing: the SHAPE of the impedance curve (most people have no idea how flat, narrow, broad or tall it is), which entirely determines the sonic changes that the resistor will create and is not something you can control.  And increasing source impedance increases distortion, reduces damping, and has other side effects which I dislike.  
 
I REALLY don't like EQ, but I like messing with impedance even less.
 
In the end, I'm a purist: I never modify frequency response via analog or digital means, other than oversampling to reduce anti-aliasing artifacts.  The speaker or the phone does what it does, and fussing with the signal to change that just creates more problems than it solves.  It's my bias, I freely admit it.  
 
You don't have to agree, but don't say I didn't understand or listen, I just have a totally different approach.