drtturnip
100+ Head-Fier
- Joined
- Dec 3, 2011
- Posts
- 246
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- 24
I have always liked these headphones but felt that they had a little more to offer. My complaints were twofold and common. Lack of bass and a slightly phased blurred upper mid. I have been running them through a modified harmam kardon hk505. I dropped the series 470 ohm limiting resistors with 100 ohm and 10 ohm to ground thus lowering the output impedance from 470 to 10.
My theory on the blurred upper mid was that by design Sennheiser uses the baffle and ear cup interaction to widen the sound stage and create a more room like presentation. However this interaction was causing the blurring. Since I was more interested in accuracy (music production) I thought I would try a few things.
I removed the pads and then the snap in driver covers. I cut out two sheets of double ply pleated paper towel to fit under the snap in covers with a hole for the driver. This effectively limits the interaction between the ear cup and and ear area by covering the chambers built into the baffle. The results were promising as I was now able to run the bass control much lower and the upper end was clearer. I new I still had interaction because if I held my hands over the ear cups I could hear the mids jump up. I then removed the drivers and placed another two sheets of paper towel inside against the outer ear cup against the perforations along with a thin layer of poly which was cut as to not touch the back of the driver. I also cut a small plug of open cell foam and inserted into the hole on the back of the driver. (If its good enough for the hd650 then why not?). This really cleaned things up and it is easier to hear small details which otherwise would have been hidden. The trade off (there almost always is) is that I think the sound stage has shrunk, but that was not my goal. Now if I only had a multi thousand dollar testing device I would post pretty little graph. I attribute the fuller bass to the simple fact that the reflection of the upper mids into the listen area have been dramatically reduced, thus shifting the frequency response and at the same time reducing smear.
My theory on the blurred upper mid was that by design Sennheiser uses the baffle and ear cup interaction to widen the sound stage and create a more room like presentation. However this interaction was causing the blurring. Since I was more interested in accuracy (music production) I thought I would try a few things.
I removed the pads and then the snap in driver covers. I cut out two sheets of double ply pleated paper towel to fit under the snap in covers with a hole for the driver. This effectively limits the interaction between the ear cup and and ear area by covering the chambers built into the baffle. The results were promising as I was now able to run the bass control much lower and the upper end was clearer. I new I still had interaction because if I held my hands over the ear cups I could hear the mids jump up. I then removed the drivers and placed another two sheets of paper towel inside against the outer ear cup against the perforations along with a thin layer of poly which was cut as to not touch the back of the driver. I also cut a small plug of open cell foam and inserted into the hole on the back of the driver. (If its good enough for the hd650 then why not?). This really cleaned things up and it is easier to hear small details which otherwise would have been hidden. The trade off (there almost always is) is that I think the sound stage has shrunk, but that was not my goal. Now if I only had a multi thousand dollar testing device I would post pretty little graph. I attribute the fuller bass to the simple fact that the reflection of the upper mids into the listen area have been dramatically reduced, thus shifting the frequency response and at the same time reducing smear.