twgib
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Post by twgib on Jun 9, 2018 16:17:00 GMT
I'm having a hard time deciding which treble mod to perform on the beyer t90, the treble peak is undoubtedly too much for me and takes away from the rest of the spectrum, I figure it can be any one of these:
1.) 1 ply of TP
2.) 2 ply of TP
3.) 3 ply of TP
4.) 2mm synthetic felt
5.) 3mm wool felt
6.) a LCR anti-resonant filter circuit
Any thoughts?
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solderdude
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measureutternutter
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Post by solderdude on Jun 9, 2018 19:05:42 GMT
I'm having a hard time deciding which treble mod to perform on the beyer t90, the treble peak is undoubtedly too much for me and takes away from the rest of the spectrum, I figure it can be any one of these: 1.) 1 ply of TP 2.) 2 ply of TP 3.) 3 ply of TP 4.) 2mm synthetic felt 5.) 3mm wool felt 6.) a LCR anti-resonant filter circuit Any thoughts? The problem with TP or felt is that in most cases it not only removes the peaks but also a bit of the highest treble. In such cases an LCR filter works best. Hard to say which will work best here.
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twgib
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Post by twgib on Jun 10, 2018 0:00:14 GMT
Frans, did you do measurements on the T90? Is the top octave rolled off? Thanks,
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solderdude
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Post by solderdude on Jun 10, 2018 7:21:11 GMT
Nope.. never measured a T90. Don't have access to one either. Golden Ears measures(d) quite similar to my rig in most cases These Russians also show the peak Tyll also shows a substantial peak.. its even worse than it looks on his pdf because of wrong compensation he used. Same measurement but with Headroom compensation which is better. So this is where I based my passive inline filter on. It will remove the treble peak only. Based on that data I would suggest LCR filtering as to not lower the freq. above 13kHz.
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twgib
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Post by twgib on Jun 10, 2018 16:54:58 GMT
Thank you so much Frans! Any advice on whether I could fit that filter in the headphones?
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solderdude
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Post by solderdude on Jun 10, 2018 17:29:06 GMT
There will be plenty of room. Be carefull when soldering wires to the driver. Maybe... just cut the wire halfway in the cup and solder the parts onto the wires instead of the driver.
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twgib
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Post by twgib on Jul 9, 2018 1:52:30 GMT
Frans, do you have any other documents that show to construct a filter of that complexity in the ear cup of a headphone? I notice it's not just a 2 component per channel filter Thanks
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Post by miiksu on Jul 9, 2018 9:05:43 GMT
You can try active carbon filter sheets. air passes easily and not overly dampen higher frequencies. One problem on those is u need alot more than TP and it will get thick. But I think that passive is way to go
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solderdude
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Post by solderdude on Jul 9, 2018 16:02:36 GMT
When you are going to drive it from a low output resistance source you can leave out: R1, R2, L1, L2, C1 and C2.
So that leaves 3 components (all in parallel) that have to be mounted in series with 1 of the wires to the driver.
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twgib
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Post by twgib on Jul 10, 2018 2:41:40 GMT
Thanks Frans, so do the other components help present a constant load to the amplifier even in high impedance cases? What's the risk of using a high output impedance amp with only the simple circuit installed? Does it just lessen the effect of the circuit?
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solderdude
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Post by solderdude on Jul 10, 2018 4:45:14 GMT
Indeed.
On a higher output R the bandwidth and depth of the filtering will change. That is... output R's above 10 Ohm or so.
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twgib
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Post by twgib on Jul 10, 2018 5:22:49 GMT
You can try active carbon filter sheets. air passes easily and not overly dampen higher frequencies. One problem on those is u need alot more than TP and it will get thick. But I think that passive is way to go From your experience how much is "thick?"
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Post by miiksu on Jul 10, 2018 5:47:04 GMT
You can try active carbon filter sheets. air passes easily and not overly dampen higher frequencies. One problem on those is u need alot more than TP and it will get thick. But I think that passive is way to go From your experience how much is "thick?" 2-3 mm ply. I used 1mm x 3 plys on different headphones. Need thick pads also.
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