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Simon7011
New Head-Fier
Hi, as a new member but a long time reader, I'd like to pose a question that has been bothering me for as long (about a year) as I have been making my own headphones. I have spent a lot of time building and tuning loudspeakers so I am not new to the building world, but headphones have a few strange problems which I am keen to understand.
I am experimenting with the different ear cup types, open, closed, and somewhere in between. What I am finding is somewhere in between is where I seem to find the best tuning for most of my headphone attempts. I am making my ear cushions using a thin stretchy PU covered cloth which looks like leather but is very light weight. The foam is open cell memory foam, also fairly light-weight as used in chair cushions.
I have tuning holes drilled into the baffle (fibreglass sheet) holding the 40mm speaker driver (bought on ebay for £15 a pair and are a composite fibre/mylar cone Number on the magnet is WBM16032). The tuning holes are covered by felt stuck to the inside of the baffle. On the front side of the baffle I use electrical tape to cover the tuning holes if I'm not happy with the sound. The rear cup is made from a piece of MDF which I've hollowed out using a router to provide a sealed enclosure for the rear of the driver. (I'll try to post pictures but as a newbie it may take a little while to get these posted.) For now, the rear cup is held in place using a non-drying modelling clay a bit like blue-tack.
What I keep finding with my closed cup designs, is that to develop the lower end of the spectrum, I need to create some leakage around the rear cup. The cup is still providing acoustic support to the driver, and I can use the tuning ports in the baffle to change the mid to high frequencies, but without the rear leakage I cannot get satisfying bass response.
Is there a way I can close the rear cup to reduce the sound that leaks out, but still get the lower end bass response that I want? Can the rear sound wave from the driver be damped or ported somehow so it doesn't interfere with the front wave? Am I missing an easy trick?
Any help or guidance would be really appreciated because this has me stuck.
I am experimenting with the different ear cup types, open, closed, and somewhere in between. What I am finding is somewhere in between is where I seem to find the best tuning for most of my headphone attempts. I am making my ear cushions using a thin stretchy PU covered cloth which looks like leather but is very light weight. The foam is open cell memory foam, also fairly light-weight as used in chair cushions.
I have tuning holes drilled into the baffle (fibreglass sheet) holding the 40mm speaker driver (bought on ebay for £15 a pair and are a composite fibre/mylar cone Number on the magnet is WBM16032). The tuning holes are covered by felt stuck to the inside of the baffle. On the front side of the baffle I use electrical tape to cover the tuning holes if I'm not happy with the sound. The rear cup is made from a piece of MDF which I've hollowed out using a router to provide a sealed enclosure for the rear of the driver. (I'll try to post pictures but as a newbie it may take a little while to get these posted.) For now, the rear cup is held in place using a non-drying modelling clay a bit like blue-tack.
What I keep finding with my closed cup designs, is that to develop the lower end of the spectrum, I need to create some leakage around the rear cup. The cup is still providing acoustic support to the driver, and I can use the tuning ports in the baffle to change the mid to high frequencies, but without the rear leakage I cannot get satisfying bass response.
Is there a way I can close the rear cup to reduce the sound that leaks out, but still get the lower end bass response that I want? Can the rear sound wave from the driver be damped or ported somehow so it doesn't interfere with the front wave? Am I missing an easy trick?
Any help or guidance would be really appreciated because this has me stuck.
