Dear community, I have a pair of Peerless PMB 100 orhodynamic headphones. I just checked with a swept tone and there is no audible output below 35...40 Hz. I came to the idea that the reason might be acoustic short circuit. They are, like most orthos, an open type. The actual drivers are round...

There is definitely no double cavity. The diaphragm is about 4.5 mm (3/16") from the front surface, not counting the earpads. There is no leak from the back to the front. There is a 'cavity' behind the diaphragm, it is 17 mm deep (11/16"), undamped, apart from some thin dust-protecting fabric...

I disassembled my Peerless PMB-100 headphones, and sealed all the holes on the baffle around the diaphragm with masking tape. I also applied a thin layer of black felt at the whole rear surface of the headphones, just behind the covering grille. Unfortunately the bass did not increase much, only...

I bought my pair of EAH-820 long, long time ago. One may get another pair only by chance. I have seen one on eBay (it's a pity I missed it): http://cgi.ebay.com/ws/eBayISAPI.dll...m=230060193781 However, I have seen a technical brochure on this line of product...

Hey Wualta, Thanks for processing my scan an republishing it in this thread. Actually my EAH-820 and your EAH-830 differ only in some minor details. The external face of the 820 is formed from the plastic case as a grille, painted with silver paint (unlike the 830 which looks for me woven...

This is the intact diaphragm indeed. The other is broken. I tried repairing it with "liquid silver", a PCB repairing fluid, but no avail. I contacted a company who scanned it and probably it is possible to transfer the pattern to the foil, but I have no idea how to do it. Someone suggested that...

I am also a proud owner of a pair of Peerless PMB 100. I purhased them from Germany, and of course I disassembled and inspected them inside. I also recabled them internally, painted the internal felt black and repainted the rear metal grille. I replaced the ear foam with thin perlon wool covered...