Orthodynamic Roundup - Page 434

First, congrats to Eric on the T30 deal of the decade. Lay your traps for the seller who buries the good stuff in the text of his auction, who misspells things because he's in a hurry. The best deals are always hidden.. by accident... and patience pays off. It's the ninjiujitsu way.

The seller told me the T30s were all in good shape, though they won't be in their fancy Fostex vinyl cases (big deal!).

Studying the T50RPv2 has taught me (and reminded me of) something else about earpads: Even if they're airtight, they have to have enough of what the acoustics boys call "surface density". In other words, they've got to have some heft, some mass. The original T50RP had no bass because of the small size of the driver, true, but it also had no bass because the earpads were light, as if they were filled with cotton candy. Artificial sweetener cotton candy. Bass just passes through them the way it passes through the limp dust covers of an electrostat.

The new earpads, though not that much thinner, are more like slabs of meat. You can press the T50RP to your head, collapsing the original pads to thinner than the new ones, and you still won't hear bass like the new pads deliver. So do what Smeggy's doing-- whatever you choose for earpads, make them as dense as you can. Sometimes this will be practical, sometimes not. Thin and fluffy will be better than thick and fluffy, but thin and the consistency of veal would be ideal.

You can begin to see why Koss originally used mineral-oil-filled earpads for the ESP/9. And the Pro 4AA, for that matter. Even my Sharpe 660s used oil-filled pads for the single purpose of blocking out all ambient sound (they certainly had no bass to speak of).

Smeggy's supracircumpads work because both pads seal to your ear and/or head. The original T40's foam rings didn't make it all the way to make a seal, though they touched your ears, and the result was simply a messed-up midrange. Now, do Smeggy's weatherstrip rings do a subtle number on the T40's midrange too? It's likely they have some effect. Could be good. Depends. You'll have to try it for yourselves. Kinda makes you wish manufacturers would make adjustable earpads, doesn't it. Then you could trade off bass for midrange smoothness, because any time you have a sealed cavity, cavity resonances show up.

In a way, the ideal earpad would be one built up from discs of soft leather. DAC, take note. I'd love to see you get some real bass from the HOK. The original earpads were thin leatherette. See what you can do with some thick-walled earpads. That's the stuff you need.

The original T50RP really did sound lousy, honest.

The ATH series of electret 'phones by A-T were notable for being very midrangey. A different stargety is called for. If you cover the cups with your hands while they're playing you may hear something you like. Absorb, reflect. Let us know what you find.

Great stuff, guys. Keep it coming.