MrHee
New Head-Fier
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- Mar 9, 2012
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Mainly inspired by thelostmidrange I decided to do my own experiments on cup tuning. this thread is not meant to give be all end all opinions. it is intended to be more of a journal of my fwj exploits.
all comments are welcome and the interest in my jorney is appreciated.
for the sake of conserving funds i'm doing the tunings on a set of grado sr60i.
first off, I wanted to test out a certain cup geometry ive been thinking about. the theory is to create a convex shaped opening, meaning the chamber will be slightly flared out as you go from the driver to the face of the cup.
i don't really have any scientific basis for it but i've heard that paralell walls and standing vibrations are not good.
I also figure that it will help channel the vibrational soundwaves in the air away from the driver.
to test this i started by liberating one of the drivers from the plastic housing. then i turned my first prototype of my concept out of some crappy pine bed i had lying around in my garage.
I compared the stock plastic vs the wood cup with mono recordings of purple haze and some gerry mulligan.
I thought the sr60i sounded pretty decent but when i heard it with a fwj it was amazing how crappy the stock plastic sounded.
to describe the effect i would have to say the plastic made the sound feel veiled and canned in. the sound out of the pine cup had much more space around each instrument. the highs really felt much more aired out. It felt like finally being able to stretch after sitting in a car for an extended ammount of time.
with the stock plastic i also noticed a strange sort of echo like distortion in the mid and high range. the pine cup pretty much pointed it out to me.
also, with having more air between the instruments, the bass felt less flabby and muddled in complicated passages.
the pine cup also has a much more natural decay and timbre (if thats the right term) of the high hat.
I was definitely amazed. I went out and bought some real wood to continue my experiments.
i picked up some zebrawood and genuine mahogany. unfortunately i totaly forgot to make sure they were dried so the zebrawood i have will probably be unworkable for another year or two. but luckily the genuine mahogany was dry enough to work with (probably kiln dried).
I then made a few cups to test a couple variables. first i wanted to test the difference in tone in the woods. I turned 3 cups out of the mahogany. 1 was similar to the pine but with a slightly different outside design.
the design i made still had a few variables that needed to be worked out but the overall shapes were similar enough for me for now.
The other two cups i left in a rough form with a straight chamber with paralell walls. the variable i wanted to test with these was length so i cut one to 1 3/4" way above thelostmidrange's harmonic length. The other was cut to 1 1/4" which is about the length that thelostmidrange had the most luck with.
testing was done with mono recordings of jimi hendrix, frank zappa, and gerry mulligan
testing results...
flared mahog cup sounded very similar to the pine. The mahog to my ears was a bit better though. i would say total it was about a 1-2 percent improvement in overall sound.
to give that number some reference i would say that my grado sr60i's are about a 10-15 percent improvement in overall sound compared to my dt 770 pro80's.
the difference between stock and fwj grados is about an overall increase of about 5-10 percent in sound quality.
once again these percentages are not any kind of basis for what these headphones really sound like. i would like you to think of it as a reference for my statements in overall sound improvement as per my tastes.
The mahogany to my ears has a much more pleasant soundstage. the instrumental seperation is increased and each sound fits in its spot very well. the pine, although it did open up the overall soundstage, has a strange sort of blended squashed effect to the sounds. they feel like they mush over each other instead of sitting in their seats. the highs are a bit higher on the mahogany but it isn't any more tiring because of the increased feeling of air around them. also the snap and decay of the hi hat is a bit more natural with the mahogany.
i then tested the harmonic length theory. first i put on the 1 3/4" straight chambered rough formed cup.
horrible...
it felt like i went almost all the way back to the stock plastic. that tin can effect was back in full force. thick sludgy highs. strange sort of mid range echo and distortion. flabby and less impactful bass. total probably about 1 percent better than stock plastic.
i then compared the two straight chambered different length cups to each other.
the shorter 1 1/4" cup sounded about 3 percent to 5 percent better than the 1 3/4 cup
the tin can effect was reduced dramatically. the low end was still a bit flabby but much more impactful than the longer cup.
so far, in my opinion the flared design is the biggest factor in sound improvement.
I hope the improvement in sound isnt just placebo caused by my ego... it would be nice if someone else could try the flared cup design to see if they get similar improvements in sound. or maybe this was always known and just not commonly done because it minimizes the ammount of the shiny beautiful face grain. overall though i think its worth it.
pretty lengthy beginning, thanks for reading.
what i'm working on right now is testing the difference between thicknesses of the walls. the variables i'm testing are the size of bead on the end of the cup and also the wall thickness at the cove for the gimbals.
testing with shellac finishing (inside and out), and different woods (figured koa, figured curly walnut, tiger maple, cocobolo, zebrawood, bocote) comming soon !!