CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Lobby => Headphone Measurements => Topic started by: Marvey on February 15, 2012, 01:28:26 AM
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One of the things I never liked about the HP1000s was a certain shoutyness that they had in the midrange. I came up with an idea a long time ago after measuring the liberated drivers of the SR80:
http://www.head-fi.org/t/566929/headphone-csd-waterfall-plots/105#post_7735041 (http://www.head-fi.org/t/566929/headphone-csd-waterfall-plots/105#post_7735041)
I realized this shoutyness was caused by the cups and not the driver. In CSDs, we can see the shout as a ridge around 2-3kHz. For the HP1000 cups, it's 3kHz.
http://www.changstar.com/index.php/topic,24.msg196.html#msg196 (http://www.changstar.com/index.php/topic,24.msg196.html#msg196)
The way I reduced the shout on the SR-80 was to line the inside of the cup with good ol' Creatology Foam Sheet material. So I did the same to the HP1000. In addition, I also applied a small circular piece on the back of the metal button. I wanted to eliminate, as much as possible, the sound waves bouncing inside of the HP1000 cup.
(http://www.changstar.com/index.php?action=dlattach;topic=119.0;attach=596;image)
The resulting changes were rather impressive. Even more neutral than before. No more mid shout. In addition, this mod brought out some details which were masked by the midrange shout. Everything sounds super smooth and much more refined than before. In other words, I've sort of re-discovered the HP1000 and am listening to them a lot again.
Before mod:
(http://www.changstar.com/index.php?action=dlattach;topic=119.0;attach=598;image)
After mod:
(http://www.changstar.com/index.php?action=dlattach;topic=119.0;attach=600;image)
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Very cool. That creatology foam is great stuff. CEE TEE brought me a couple squares and I've used it in 2 orthos now with good effect. It seems to be able to absorb quite a bit in a fairly even way. Certainly better than felt or Akasa foam. Felt is more uneven in it's effect and Akasa just sounds weird.
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I agree. Akasa sounds wierd - does wierd stuff.
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Updated with measurements