Hi guys, I didn't find how to start a thread, but I guess I'll get your attention here...
So I've modded my T40 RP that had been In a bottom of a box for like 10 years cause I tought they sounded liker cr. For all the questionning, Is it the same driver as the t50 or not? Can't answer that but I do know that they sound sound superb right now, with disclosure that I don't have anything Hi-end to directly compare them to. All I can say is that they are defenitly sending my Allessandro MS1-i to the same box the t-40 was, It's just a non contest my T-40 beats them on every possible criteria and then some. Other disclosure, I don't consider myself a audiophile but I do have trained ears, I've been a live sound audio engineer for 15 years (and the T-40 will definitly be used as a tool mainly, and to listen to music on my neighboor sleep hours...) I still like speakers..
So, what makes a t-40 a closed back headphone is a little plastic slab covering the vents, just glued there. So for a start I removed that and made the assumption, accurate or not, that I was starting with a T50 RP.
I didn't know where to find dynamat or similar, so I just got creative and Used pieces of stick on wooly stuff (the kit to put under the leg of tables and chair) on the deeper parts of the cup, and stick on cork for all the places that was asking for more flexible thinner material, more precise scissor work. I'm adventurous like that. The other thing I did was the treble dot thing but a little differently, I sandwiched the square piece of felt under two layer of micropore tape. I did also buy the transpore, but my gut feeling told me to use micropore, cause it feels very similar with the material that's already on the back of the driver, so It was adding more of the same and it felt more permeable. For bass ports, I first blocked the top two vents with electrical tape. the bottom two were covered with micropore, again to mimic the T50, it look that it's what they did, and with cork I reduced the width of the port to about 3 mil. so two vents high, 3 mil wide. I tried some cotton filling, but didn't like it. Correct me if I'm wrong but there is more bass if you leave the cup empty. Oh, and yes, perhaps the most important, I went for Brainwavs HM5 pads, very tight fit, hard to put on but very good seal, confortable, but too sweaty, and look a bit goofy cause very thick.
So there you have it. It sounds good, very good, but of course once you get there you want more... I was not only posting to share my succes story, I do have question.
Bass extension: I could use more, It already got much better, and again way better than my allesandro but that's not hard, this thing has no bass. Is it how much I'm gonna get? I have a pair of Koss Porta-pros, and that's one thing they do great. Deep, controlled bass. I'm thinking if koss can achieve that with such a small driver, and no sealing whatsoever, is there ways to get more from the orthodynamic one or that's it, that's all there is. Don't get me wrong, my Mod t40 sounds much better than my porta-pros, but I still love those little cans, to plug direct in my Ipod, go to the gym or for a run. weightless, cheap, ...and thick round bass in enjoyable quantity (and actually a quite nice sonic signature, it's not all about the bass).
Before you call me a bass head...I don't think I am, but there's stuff down there. Did you guy's know that a Piano lowest note has a fundamental of 37.5 Hz? I'm listening to my t-40 right now, and for fun, I fade in my 12" sub woofer, 80 Hz crossover, and it's like...Yeah, there it is, now we're talking... So any cues how to achieve lower bass response is welcome.
Speaking about response. I'm curious, how do you guys measure that? I'll go for my ears before a graph any day, but obviously I use measure microphone, pink noise and some RTA every day, but headphones? If there is one thing that's obvious is that the way the pad seal around your ear have an impact on the frequency response, it's a major part of what you hear. So how to measure that? mini microphones stuck in the ears of a dummy head with headphones on? just curious, cause a headphone on a stand definitly don't sound like a headphone on your ears right?
Thanks for your input.
but its damn expensive, everyone can print guides by themselves but that would be about 35-45$ for pair, that's why I will make those castings. Here are some pics of printed elements (sorry if pictures aren't the best you saw in your life
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) try various materials inside and don’t put too much or you will overdamp it and it will soak life from headphones. Try beewax ( damn why no one want to try bee wax! ), and various natural cotton and hardened wool (I used same stuff like you) you can punch holes inside wool. And finally seal everything with ketchup, ketchup batch is the secret way of the pro's, use spicy one (just joking, dont do that). The thing with the bass is it can flood on mids and then arghh... Make sure you sealed everything nicelly, also ear pads
