ATH-M50: Effect of extra impedance on sound quality

[sup27606]

I was playing with a 100 ohm headphone attenuator from Ultimate ears with my Ety HF5 and as suggested in these forums, it did improve the clarity of the highs. Then out of curiosity, I tried the same experiment on an ATH-M50. The setup was Fiio E7 --> UE 100 ohms --> ATH-M50. To my surprise, the M50s also sounded more clearer/higher resolution and soundstage also seemed to improve to an extent. The jazz numbers sounded much better for example. However I had to increase the bass by 3 db to get close to the original sound.
 
Has anyone else experienced the same with ATH-M50, or is it just me (sound perception could be subjective). I was surprised because according to the knowledge base on head-fi, increasing the impedance attenuates the high frequencies more compared to the low frequencies. Here, I found the opposite with M50 and also the Ety's. Could someone explain please. Thanks very much.

 

[kimvictor]

  I was playing with a 100 ohm headphone attenuator from Ultimate ears with my Ety HF5 and as suggested in these forums, it did improve the clarity of the highs. Then out of curiosity, I tried the same experiment on an ATH-M50. The setup was Fiio E7 --> UE 100 ohms --> ATH-M50. To my surprise, the M50s also sounded more clearer/higher resolution and soundstage also seemed to improve to an extent. The jazz numbers sounded much better for example. However I had to increase the bass by 3 db to get close to the original sound.
 
Has anyone else experienced the same with ATH-M50, or is it just me (sound perception could be subjective). I was surprised because according to the knowledge base on head-fi, increasing the impedance attenuates the high frequencies more compared to the low frequencies. Here, I found the opposite with M50 and also the Ety's. Could someone explain please. Thanks very much.

Well it does tend to alter high frequencies more often, but it depends on the driver characteristics. For instance, the DT1350, at least according to Rin's measurements, displays increased treble by 1db. I know it doesn't sound like much(and it's really not), but it shows that treble doesn't have to get attenuated with added impedance. Few other products, like H-200 by T-PEOS displays reduced bass and increased treble with added impedance.

 

[sup27606]

Thank you, Kimvictor. I agree with you, it will depend on the impedance characteristics of the headphone at different frequencies. Comparing the impedance response of Ety-HF5 and ATH-M50 from innerfidelity, it seems, ety's impedance starts to increase sharply beyond 2K, while M50's impedance remains almost unchanged. So there should be a difference in sound changes between the two headphones upon adding extra impedance. In my case, I observe the same effect in the two headphones, a slight increase in treble with better resolution and clarity. I was reading through this thread (http://www.head-fi.org/t/234518/adding-impedance-to-headphones) trying to follow the discussion, but there were too many comments. At the end, I got lost.
 
It may all be my perception. If someone else has tried this with their M50s, I would be interested to hear their impression.