solderdude
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Post by solderdude on May 14, 2013 20:18:44 GMT
It's possible Tyll had a dodgy pair. He did mention the HD681 sounded more balanced and the HD668B had more bass. I also had one pair that appeared to have no bass at all for the first half hour (on both drivers !) and only became better after a few hours of hard labour. Judging how he speaks of these headphones I wouldn't be surprised he would not have spent much time on these. Strangely enough Tyll's measurements usually are quite accurate (when you look past the wrong HRTF correction he used)
I have redone my HD681 filter and am working on an article. As the EVO and original one have almost exactly matching FR plots that filter should work on the EVO equally well.
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Rabbit
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Post by Rabbit on May 14, 2013 20:27:10 GMT
The orginal filter that I have works well, Frans. What are you correcting?
From what I've heard, the Evo is extremely similar in the bass. I was originally comparing it to a 681b which is quite different down there. The HD681 has a big bass just like the Evo. The biggest difference is in the treble. The Evo seems more even handed and doesn't sound quite so 'paper like' in the treble as the original.
I've stuck with it and I like it a lot actually. The bass hits hard but very pleasant for a lot of stuff.
It wouldn't surprise me if Tyll prefers the Evo when he hears one.
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solderdude
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Post by solderdude on Jan 19, 2014 16:55:11 GMT
Most people will have heard of the 'Kramer mod' which basically means opening up the grille in front of the driver by drilling a different pattern in there. Results are published here: diyaudioheaven.wordpress.com/headphones/measurements/brands-j-r/This mod may be more interesting for KSC35/PortaPro owners than for KSC75 owners.
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Post by c61746961 on Jan 19, 2014 17:18:57 GMT
Very nice, thank you!
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Post by c61746961 on Jan 19, 2014 18:56:46 GMT
Moreover, are you planning to measure the effect these have on the PortaPro?
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solderdude
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Post by solderdude on Jan 19, 2014 19:44:56 GMT
I may test the effect on my KSC35. The measured PortaPro is not mine The results from a KSC35 should be similar to that of a PortaPro.
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Rabbit
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Post by Rabbit on Jan 19, 2014 20:01:47 GMT
Frans, when you've finished with the fake Portapro, perhaps measure the KSC75 on the band? I quite like it. It seems to gain a little weight. (I think) Considering its price, it's an extremely good buy.
Question is is it such a good buy if you use a fake porta headband at £29 (about) plus the cost of the KSC75 itself. (£12) So the total is around £41. Getting a bit high but the two together really isn't bad at all.
If the fake measures close, then perhaps drill that one out? (If it is actually a fake!!)
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Deleted
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Post by Deleted on Jan 26, 2014 20:15:36 GMT
Here's his comparison of Superlux HD681 and 668b. I've just come across this and I find it very odd as well. In fact wrong would be more accurate. I have both the 681 and the 668 and to be honest, it looks to me as if there has been a simple mistake in typing up and titling the graphs. The graphs actually make sense if you read the red plot as the 681 and the blue plot as the 668. Further on in the thread Frans says that Tyll mentions the "681 sounded more balanced and the 668 had more bass". This is the exact opposite of how they sound! The 681 is the bass-monster, and the 668 much more balanced. In fact a very nice phone indeed for not a lot. So I think that's what happened - someone has made a mistake when typing up the info before publishing. We're all human. P.S. - well most of us. Read more: diyah.boards.net/thread/135/koss-ksc75?page=2#ixzz2rXNmNoKw
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solderdude
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Post by solderdude on Jan 26, 2014 21:14:03 GMT
When these plots came online I already talked to headroom about the plots being incorrect. They agreed the HD681 has much more bass but said impressions and measurements have little correlation sometimes and that Tyll doesn't make mistakes (he measured them). Tylls pdf's have the same measurements but strangely enough the impedance plot is correct. I threw tons of evidence their way but they did not react after that. It is the first HD681 I've seen that rolls off below 100Hz ! Maybe they had the F version but Tyll is holding up the red one in his video.
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Post by c61746961 on Jan 30, 2014 1:19:33 GMT
These guys sell modded KSC35/75/PortaPro with either grills, kramer modded and lacquered driver mesh, and a 47 ohm impedance adapter. What kind of difference would such an impedance adapter make?
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solderdude
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Post by solderdude on Jan 30, 2014 6:07:58 GMT
The effect would be a drop in efficiency of 5dB and an increase of bass of around 1dB (hardly worth mentioning) The plot below shows the effect (on a KSC35 which is a PortaPro without the 5kHz peak) but using a 120 Ohm 'adapter' which has a 10dB drop in efficiency which is too much when driving it from most DAPs.
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Post by c61746961 on Jan 30, 2014 17:05:00 GMT
Oh, that's kinda underwhelming!, as if they needed more bass ... Thanks!
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Post by c61746961 on Jun 12, 2014 3:15:06 GMT
FYI: These now come with a 45 degree plug with strain relief, same as the PortaPro Classic.
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solderdude
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Post by solderdude on Jun 12, 2014 5:06:12 GMT
I bought my KSC75 about 7 years (and a second hand KSC35 as well in that period) ago and both had a 45 degree angle plug:
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Post by c61746961 on Jun 12, 2014 6:15:37 GMT
Hah, the KSC75s I bought last year had a really poor straight plug like this one.
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