CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Lobby => DIY => Topic started by: stratocaster on April 05, 2015, 08:43:33 AM
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I thought it could be useful to provide visual info on what effect certain modifications have on the FR or CSD performance of headphones. This might help people to find the right stuff to use on trouble spots of their headphones. I am going to start with the effect of mesh removal on my HD580s.
The attached pictures show measurements of the headphones with mesh in place (pics 1, 2) and with the mesh removed. Have a look at the area between 2 and 5 Khz. The mesh seems to bring 2.5 and 4.5 kHz up. The CSD, which is nice overall, is affected negatively. Without the mesh the CSD is awesome.
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Effects of different materials in front of the driver - carried out on a modified open-backed T50RP.
All pics show the stock version (so without front-side damping) in red vs a front-side damped version in green.
Pic1: felt (2mm)
Pic2: toilet paper (2 layers)
Pic3: toilet paper under felt
Pic4: tp (1 layer)
Pic5: tp under beyerdynamic foam (comes with DT250)
As you can see, effects begin at 2kHz, frequencies below are unaffected. Personally, I would choose a layer of toilet paper ...
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It is useful, thanks!
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This is exactly the kind of thread I've been waiting for someone to make.
Thanks for posting. Looking forward to seeing some of the mods from your recent closed grado build.
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I have recently come across something that I am not yet sure will really turn out to bring real sonic improvement to Sennheiser's HD600 or 650 headphones. But it surely changes HD600/650 bass and midrange, boosting the whole FR from about 20Hz up to about 2 kHz it for a constant 3db.
Have a look at the measurements, try out the simple mods and hear for yourself if you like it or not.
It's all about the Sennheiser 'screen' ...
For the measurements the volume was unchanged when measuring modded and unmodded versions.
HD650 modded (green) and unmodded (red):
(http://www.changstar.com/index.php?action=dlattach;topic=2270.0;attach=10950;image)
HD600 modded (green) and unmodded (red):
(http://www.changstar.com/index.php?action=dlattach;topic=2270.0;attach=10954;image)
Now, who could be the target group for the mod? I guess, most probably those who find their HD600's 3-5kHz response too forward. By elevating the response from 20Hz up to 2kHz, the 3-5kHz range will correspondingly go down a good 3db in comparison. Of course, so will the rest of the FR upt to the treble.
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Here's the mod. As the pic shows, it's a simple 2-step mod. First cut a coffee-filter 'screen' plus a corresponding foam, place the pieces above the 'silver screen' in the cup, et voilá. Quick, easy to install and remove. Try it and help evaluate.
(http://www.changstar.com/index.php?action=dlattach;topic=2270.0;attach=10956;image)
PS: Foam behind the driver has been left untouched, front foam has been removed.
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Looking at HD650 and what the mod does distortion- and CSD-wise ...
Stock FR and distortion at 90db/1kHz:
(http://www.changstar.com/index.php?action=dlattach;topic=2270.0;attach=10958;image)
Screen mod FR and distortion at 90db/1kHz:
(http://www.changstar.com/index.php?action=dlattach;topic=2270.0;attach=10960;image)
Stock CSD:
(http://www.changstar.com/index.php?action=dlattach;topic=2270.0;attach=10962;image)
Screen mod CSD:
(http://www.changstar.com/index.php?action=dlattach;topic=2270.0;attach=10964;image)
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Very interesting, would this mod in combination with the cotton pad mod produce a downward tilting FR?
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Very interesting, would this mod in combination with the cotton pad mod produce a downward tilting FR?
Yes
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A) What is that first picture exactly?
B) Any of these layers go under the pads?
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A) What is that first picture exactly?
B) Any of these layers go under the pads?
Basically you have 2 cutouts, the first made of coffee filter paper, the second made of foam. Both cutouts cover the same area as the Senn silver mesh, but I leave a circle over the driver open.
Both cutouts are put under the pads. The bass effect is mostly due to the coffee filter paper, which makes the silver screen less air permeable, the foam exerts pressure on the paper against the silver mesh.
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Very interesting, would this mod in combination with the cotton pad mod produce a downward tilting FR?
See for yourself. HD600, screen and cotton pad mod in place:
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That looks pretty yummy, now I'm sure what my next purchase is going to be. Thank you as always.
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Can I get a link to the cotton pad mod for quick reference?
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See for yourself. HD600, screen and cotton pad mod in place:
Do you enjoy this particular configuration or would you rather have a flat FR?
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Solderdude compiled a very comprehensive list of mods and their effect with various measurements per mod here (http://www.mediafire.com/view/d9kb768up61eh3b/HD650_modifications.pdf).
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Can I get a link to the cotton pad mod for quick reference?
Just put a cotton pad behind the driver or replace the foam over the back of the driver with some denser/thicker foam. But you can easily get too much of the effect, then the bass would deteriorate. It certainly helps to have a measurement rig to assist you.
Do you enjoy this particular configuration or would you rather have a flat FR?
Personally, I prefer the flat response. This mod makes the HD600 sound too much like an HD650, which I also got. So, I prefer to have the stock HD650s and complement it with a flat HD600.
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Have you toyed around with other pads on the HD6X0?, I'm particularly interested in seeing the effects of the HM5 angled velour pads.
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Have you toyed around with other pads on the HD6X0?, I'm particularly interested in seeing the effects of the HM5 angled velour pads.
Yes, I have. Didn't try the HM5 angled velours, just the plain velours and pleathers. But no pad performed as well as the Sennheiser pads.