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Posts by stratocaster

Looking for some NAD RP18 vintage orthos. Have to be the MYLAR version, since I have already got the Kapton one. I will only be using the drivers for a project, so the headphones don't need to be in perfect shape.
 As a matter of fact, just using velours will not do the trick. I tested lots of (p)leather and velour pads together with internal damping ... Only Beyerdynamic DT250 pads on top of a foam ring scavenged from a cut-up Grado L-cush sounded good, flattening out the frequency response.
FWIW, measurements of different pads ...   1. on-ear (p)leather pads:   2. over-ear (p)leather:   3. on-ear foam pads:
What cup have you got, wood or plastic? Anyway, the paper plus cotton is rather thin and if you have a shallow cup, you can keep the open-cell foam disc just thick enough to exert some pressure of paper and cotton against the driver. But, the damping is absolutely necessary, there is no way around it. I had the damping in my SR325 cup and it worked just fine.
You have to dampen the backwave of the driver by placing some absorbing/reflective material behind it. With this setup I am using three layers: some damping paper like coffee filter paper and over it a 5mm-layer of compressed cotton (both in the shape of a horseshoe, which has to cover the venting holes around the magnet). Finally, I use a disc of  about 2cm of open-cell foam, which is compressed when you close the cup and which presses the damping paper and cotton against...
No, it won't be less airy. The damping is affecting the mid-bass and midrange mostly. The higher frequencies providing air will not be affected, really. In fact you may even have to bring them down a bit (felt in front of the driver), because the masking effect of the mid-bass hump will be gone. The result is a very balanced sound, the Grado shout is eliminated and the headphones will sound a lot more neutral.
GradoMagnums have a mid-bass hump and serious bass roll-off, combined with elevated higher frequencies. The reason for this is the foam pads that let too much bass energy pass through. But if you use velour or leather pads, there is simply too much mid bass. The solution is to combine both materials. As a result there will be less of a mid-bass hump and there will be better bass extension (resulting from velour pads AND internal damping, which in effect turns these into...
L-cush has different foam density and helps the Beyer pad keep the right distance from the driver! It's JUST 2 thirds of the L-cush glued to the back of the Beyer pad. Did LOTS of experiments (plus measurements), and this is just the right setup.
 It's easy: Cut off around 5-7mm from the top of the Grado L-cush and glue the remaining cush on the back of the Beyerdynamic Dt250 pad.
It has been a long time since I started this thread. Coming from the Grado modding crowd I took interest in the Magnums, then V4s, since the drivers were freely available, came at an acceptable price, and could be used in all sorts of housings. I then proceeded into the planar world, among others, and sold my Magnums, since I ultimately found them too shouty and lacking comfort.   By accident I again took some interest in these types of drivers, doing work on some used...
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