Here are some quick Grado mods you can employ for next to nothing:
1. Remove the backs from your Grados. The easiest way to do this is by carefully removing the cups from the rest of the headband (They unhook easily from the forks) and placing them in a cookie tin with just enough steaming water to loosen up the glue. (Place the cups with the driver facing up; they aren't the part that needs the bath.) You don't need boiling water nor should you leave them in too long (You don't want to warp the plastic). This is easier than it sounds.
2. Once you've gently pried the backs off, you're in a position to make a few changes. The first (and most important) is to damp the plastic inner chamber. This will clean up the presentation. Felt is good for this. Cut strips and carefully glue them so they line the insides of the chamber.
3. Put something on the back of the driver magnet. Some people use a commercial damping device, the stuff they use to damp echoey spots in car interiors. Some will tell you not to plug the two holes in the back. It really doesn't matter as those holes are just imitations of heat vents found on large subwoofers (which use a lot more juice). Still, why muck up something that's there?
4. If you want to double your bass response, pop out the holes in the back of the driver felt. Try it one at a time for comparison. There are up to ten holes you can pop. If you are planning on popping less than all, try to balance where you're popping (the PS1000 pops at 10, 12, 5 and 7 o'clock - more or less). Popping means you'll have holes where dust or debris can enter, so you need to shake and blow to make sure you get rid of anything that fell in (I always shake and blow thoroughly to remove whatever dust and/or debris has gotten in). Part of the reason Grados have these holes punched out on the higher models but not on the lower models is obvious: plastic doesn't sound that great. When you pop out the holes, the material of the air chamber does become more important, which is why you should damp it (before or afterward). If you do this, you WILL hear a huge difference in the amount of bass. The more bass you hear, the less you will crank up your Grados and the less you will feel like the top end is just too piercing.
5. Change your pads. Bowls were invented to give the Grados more soundstage. The original sweethearts - the PS1 and the HP1000 - used flats. Flats are not comfies. Flats are sold only through TTVJ. They're thinner. They're tougher. They provide a firmer contact base, which helps communicate bass. They also have a much thinner "soft" layer. It's the soft layer that leaks the bass. If you can't get flats, get black electrical tape. You don't have to tape the whole pad (nor should you). Simply apply the tape to the soft layer in the center. This is where you're leaking bass like a sieve. Do this and you will notice another big jump in bass.
If you want a serious jump in bass, buy an amp - not a pretty toy with shiny buttons but something serious. Grados get all kinds of grief over their "overly bright" sound. Truth is, you'll get equal grief from a lot of other headphones when they're not amp'd, including the Sennheiser 600/650, the Sennhesier HD800, the K701, even the beyerdynamic t1. High-impedance cans HAVE to be amped. When you run them un-amped, they sound anemic. Nobody complains about this underperformance because the expectation is "amp it or shut up." Because Grados are 32-ohm cans, making them easier to drive, people judge them unamped. When they get less than stellar bass, they condemn the unamped Grado for not doing what they're amped Sennheiser or beyer is doing. Stupid, stupid, stupid. Amp the Grado and amp it well. You'll hear a serious difference in the bass.
I have an M^3 (AMB design, copied by many). It has a variable bass boost. With that bass boost, I can pump so much bass through a lowly SR60 that you'd think you were listening to the meanest basshead cans you'd ever heard. The Grados are just speakers. YOU have to take charge over the signal running through them. If you have a tinny little iPod (like I do), don't be surprised if the bass is less than amazing. Bass requires more power. When I've hooked my SR60s up to my M^3, I've been able to make them crunch and boom and throb like nobody's business. But because of the variable setting, I can decide how much is "just right."
Remember, it's not that the Grados are "harsh" or "bright." It's that they give away the bass through their open-air design. Sparkle is a wonderful thing, but if there's nothing behind it, you'll find yourself cranking up the sound (hoping you're cranking the bass with the treble). If you end up in Shrillville, it'll be because you really didn't get enough bass with the treble. It's an imbalance that needs to be fixed - either acoustically or electronically. You can either capture that bass or double it through electronic bass boost.
Short of amping, I'd pop the holes, damp the chamber and switch to flats (or get out that electrical tape). You can make your Grados thump. You just have to make a few changes.
