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SR60-Mod - Page 38  

post #556 of 5003
Thread Starter 

 

Originally Posted by pbandstefanwich View Post

On a side note, did anything ever materialize with the carbon fiber cups? I think my friend has some, and I might be able to snag some from him if it'd be worth it!


I've temporarily shelved the carbon-fiber project until I work out the issues with the wood, but carbon fiber won't be a problem.  The shells will be easy to mold.  

 

Originally Posted by BobSaysHi View Post

Dammit Bill, you've created a monster. very_evil_smiley.gif I'll be going up to Lowes to get some wood to try different shells. I'll be experimenting with different widths and lengths, and I'm going to write a review of each shell's strengths and weaknesses.  Should I just add it onto this thread, or create another thread and link it here? Should I do all the experimenting and release it all at once, or just add onto it as I go?

 

Feel free to post here and to post as you go.  That way, there's no wait.  We all get to share in your adventures.  

 

Originally Posted by Nightslayer View Post

I've been listening to the cans for quite some time now and.. I still can't figure it out. I don't quite trust myself because its easy to hear what you want to hear, and I can't quite remember what my Grados sounded like before the extensive modding anyway. I know I love what I'm hearing now and I'm more than satisfied with what I have.. but does changing just the shell on the back drastically affect SQ? And how so, actually?


The shell isn't everything.  It's a part of a larger whole.  But as parts go, it's important.  When you vent the drivers, damp the back plate, strip the driver cloth, upgrade the wire, and remove the plastic mesh and button, you can hear the difference.  You don't need air chambers to get great HF.  The cleanest sound you can get would be to go K1000 and simply positions the driver up to your ear.  But then you'd have little bass.  The chamber lets you baffle up (and avoid signal cancellations that decimate volume).  It also lets you capture some of that runaway bass and redirect it.  In this case, the material matters.

 

I think it's interesting that aluminum has such a high velocity of sound (16,000 ft/second), which is a bit higher than hard woods (13,000 ft/second).  That's nothing compared to diamonds (39,000 ft/second) but neither is the price tag.  Still, it's not hard to see the connection between the velocity of sound in aluminum and Grado's biggest hits: the PS1, the HP1000, the PS1000 and the HF2.  The SR325 has had more mixed reviews, but I'm sure it's partly because Grado didn't vent the driver and, instead, left in a plastic ring and plastic button, both of which left a mark.  When I modded my SR325is, I couldn't believe how much better it sounded after venting, damping and limited plastic removal.  The hybrid design of the PS1000 and HF2 are undoubtedly based on the idea that wood is good for warmth, but that too much of it can produce an unwanted boominess.  The MS1000 crowd  seems to know this, which is why they drill holes or vents into their spacers.

 

Check out this site: http://www.islandone.org/LEOBiblio/SPBI1MA.HTM  It says that carbon fiber has a velocity of sound two to four times that of aluminum!


Edited by Bilavideo - 12/25/10 at 8:40am
post #557 of 5003

Okay I'm still rather confused. What exactly does the baffle do? And does the material used affect the tone of the 'phones? And what is the velocity of sound? Hahaha.

post #558 of 5003
Quote:

 

Originally Posted by BobSaysHi View Post

Dammit Bill, you've created a monster. very_evil_smiley.gif I'll be going up to Lowes to get some wood to try different shells. I'll be experimenting with different widths and lengths, and I'm going to write a review of each shell's strengths and weaknesses.  Should I just add it onto this thread, or create another thread and link it here? Should I do all the experimenting and release it all at once, or just add onto it as I go?

 

Feel free to post here and to post as you go.  That way, there's no wait.  We all get to share in your adventures.  


 

OK, maybe I was a little ahead of myself. After I build my new amp/dac, I'll experiment further. I'd like to find the best sound with my gear, instead of my old gear. With that said, having two shells was boomy, so I'll have to find some temporary solution.

 

Merry Christmas!

post #559 of 5003
Thread Starter 

 

Originally Posted by Nightslayer View Post

Okay I'm still rather confused. What exactly does the baffle do? And does the material used affect the tone of the 'phones? And what is the velocity of sound? Hahaha.

 

The baffle is the front wall of a speaker, the part the driver attaches to.  Its purpose is to separate the front of the speaker from its back.  That's because, on dynamic speakers, the diaphragm and cone push forward and back.  Forward motion produces front waves.  Backward motion produces back waves.  Without a baffle, back waves ricochet off the back wall and end up mixing with front waves.  This produces wave cancellations.  It's why most speakers don't sound very loud until you place them into a speaker cabinet.  

 

In a closed system, the back is sealed airtight; the pressure of this back wave is used to reset the cone into its starting position.  

 

In a bass reflex system, the back waves are vented, either through a passive radiator or a port placed away from the mouth of the speaker.  The bass isn't as tight as bass from a sealed "acoustic suspension" system but it's a compromise, especially when the woofer is really just an all-purpose wide-range speaker.  

 

In an infinite-baffle system, there's no back wall.  This is used mostly with subwoofers.  Having no back wall means the cone gets no help getting reset.  It's less efficient.  It takes more energy to produce the same amount of volume.  On the other hand, infinite baffles produce less resonance.  If you can force enough power through, you can get all the volume you need while the lack of a back wall means you can do it with the least amount of distortion.  

 

There are also baffle-free systems, where no baffle is required because the sound is not created by compression.  This is how dipole systems work, with sound emanating from both sides.  Think planars.  Magnepan is the Rolls Royce of this setup.

 

Grados don't have much room for a baffle; they're tubular.  There's hardly any room beyond the speaker itself.  This adds to a phenomenon known as the baffle effect.  Treble, which is directional, tends to overpower bass, which radiates in all directions.  With loudspeakers, baffle compensation involves the use of L-pads (volume controls) to turn down the treble as well as placement of the speaker right up against the wall, so the bass has to reflect off of it.  

 

Different headphones use different strategies for managing the baffle effect.  Closed phones seal the driver behind a baffle, which can take up most of the front of the headphone, just like so many loudspeakers.  The K1000 got its legendary transparency by utilizing an infinite baffle (there's a plastic separation between front and back but no real back).  Not surprisingly, the bass was a bit lacking.  The K701 is more constricted.  In addition to employing some reflective materials in its rear grill, the K701 also employs a wide disc at its mouth.  This allows the use of the wider pads and provides some relief from the baffle effect.  It's a strategy that has its fans and critics, since the K701 gets praise for its soundstage but catches grief over its bass (which is more prominent than on the K1000 but still not enough for many) and its clarity when compared to the K1000.

 

Grado's strategy is obviously to house the driver with an air chamber that surrounds the sides but leaves the rear grill open.  This is really a semi-open design.  With the back grill open, Grado is hoping to vent as much treble as possible while allowing the bass, which is less directional, to bounce all over the sides of the chamber and get reflected back into the presentation.  From a purist's point of view, this provides a less precise waveform.  On the other hand, it's the bass that's getting reflected and magnified, which is that part of the spectrum that is left lacking when you play Grados unamped.  As bass is slow, to begin with, our perception of bass is poorly directional to begin with, which is why you can put a subwoofer in a corner and never feel as if the bass were coming from "over there."

 

This is where the material of the air chamber matters.  You want something that is going to reflect more bass than anything else.  Some materials reflect more midrange and high-bass; others are more effective reproducing bass.  I've no doubt that Grado felts the low-end plastics for precisely this reason.  There's nothing to the composition of plastic that makes it particularly useful for reflecting lower-frequencies, at least not the plastic used in the Prestige line.  Whenever I've vented these plastics, I've found it helpful to either follow-up with damping (to avoid boominess) or to simply remove the back altogether.  Using woods like poplar and red oak, I've noticed improvement in the bass, but when switching to mahogany, I've been impressed at how efficiently the mahogany performed in providing so much help to the bass.

 

Brazilian rosewood has the ultimate reputation in this regard, but since it's illegal to import it into this country, I'm looking forward to hearing what cocobolo will do.  After that, I'm going to focus on carbon fiber, which has an amazing velocity of sound, with figures that bury even aluminum.

 

Velocity of sound refers to the speed with which sound travels through a medium.  The composition of the medium either facilitates such transfer or slows it down.  Obviously, the faster sound travels through the medium, the more like a driver it behaves, allowing a sharper and clearer amplification of the original signal.  According to sources like this one http://www.engineeringtoolbox.com/sound-speed-solids-d_713.html and this one http://www.islandone.org/LEOBiblio/SPBI1MA.HTM, sound travels fairly slowly through materials like rubber (40-150 m/s), cork (366-518), water (1433) and lead (1158), but it tends to zip through hardwood and glass (3962), aluminum (4877) and steel (6100).  There's more to sound than velocity itself (such as overtones), but carbon fiber's VS (11,000 to 12,000) is appealing.  No wonder they make violins, pianos and cellos out of the stuff.

post #560 of 5003
Thread Starter 

 

Originally Posted by BobSaysHi View Post



Quote:

 

Originally Posted by BobSaysHi View Post

Dammit Bill, you've created a monster. very_evil_smiley.gif I'll be going up to Lowes to get some wood to try different shells. I'll be experimenting with different widths and lengths, and I'm going to write a review of each shell's strengths and weaknesses.  Should I just add it onto this thread, or create another thread and link it here? Should I do all the experimenting and release it all at once, or just add onto it as I go?

 

Feel free to post here and to post as you go.  That way, there's no wait.  We all get to share in your adventures.  


 

OK, maybe I was a little ahead of myself. After I build my new amp/dac, I'll experiment further. I'd like to find the best sound with my gear, instead of my old gear. With that said, having two shells was boomy, so I'll have to find some temporary solution.

 

Merry Christmas!


Bob, this is an opportune moment to invest in bowls and/or jumbos.  The comfies and flats narrow the soundstage and mute the HF in order to bring out the bass.  Once you've got plenty to work with, you have the freedom to grab some soundstage.

post #561 of 5003
Quote:
Originally Posted by Bilavideo View Post

 

Originally Posted by BobSaysHi View Post



Quote:

 

Originally Posted by BobSaysHi View Post

Dammit Bill, you've created a monster. very_evil_smiley.gif I'll be going up to Lowes to get some wood to try different shells. I'll be experimenting with different widths and lengths, and I'm going to write a review of each shell's strengths and weaknesses.  Should I just add it onto this thread, or create another thread and link it here? Should I do all the experimenting and release it all at once, or just add onto it as I go?

 

Feel free to post here and to post as you go.  That way, there's no wait.  We all get to share in your adventures.  


 

OK, maybe I was a little ahead of myself. After I build my new amp/dac, I'll experiment further. I'd like to find the best sound with my gear, instead of my old gear. With that said, having two shells was boomy, so I'll have to find some temporary solution.

 

Merry Christmas!


Bob, this is an opportune moment to invest in bowls and/or jumbos.  The comfies and flats narrow the soundstage and mute the HF in order to bring out the bass.  Once you've got plenty to work with, you have the freedom to grab some soundstage.


There's a reason I haven't invested into bowls yet, and that's because my ears stick out of my head, and bowls (even reversed HD414 pads) hurt after about an hour. my solution was to cut some of the foam off of the HD414 pads (see below), so my ears would stop bleeding. Jumbos, however, are much to expensive for a high school student (without a job, mind you), however I'd like to try them.

 

A couple more mods:

photo 1 (6).JPG

 

photo 2 (6).JPG

I cut all the plastic off the side, so I can accurately hear the wood. You can see the dip I cut out for my ear.

 

photo 3 (4).JPG

Another angle on the rough cuts for my ear. Very, very comfy. I did a very rough job, if you plan it out, you might be able to do it neater.

 

photo 4 (1).JPG

 

I don't think you can tell, but the dynamat is covering any plastic on both drivers. I have a TON of this stuff, so I try and use it on anything I can. 


Edited by BobSaysHi - 12/26/10 at 12:41am
post #562 of 5003

Also, I'm starting to write my ideas down as far as testing the various diameters of wood.    

 

I figure I'll test with all these variables:

 

Cup width:

 

1 cm (max width. the cup holder doesn't even fit on the cups) vs .75 cm vs .5 cm

 

cup length:

 

4 cm vs 3 cm vs 2 cm

changed to 1 inch vs 1.5 inch vs 2 inch

 

for the 4 cm version, I'll attach two 2 cm cups together. the 3 cm version will have a 2 cm cup cut in half and attached to each side.

 

I figure I'll have to cut 5 cups for each size, and I don't have a drill press, so everything I do will be by hand (with a dremel.) I'm not going to be coating these in anything, just the wood.

 

I'll test it with my system (it's going to be a Mofset MAX and a gamma 2 with a regulated power supply that I haven't decided on yet) vs straight out of an iphone 3g

 

I'll test it with my modded HD414 pads, which you've seen above, and hopefully Jumbos.

 

EDIT: I finally broke down and ordered a pair of Jumbos. Hopefully I'll be able to resell (or return) them if I don't like them.


Edited by BobSaysHi - 12/29/10 at 12:50am
post #563 of 5003
Thread Starter 

How do you like that dynamat?  I feel a little sheepish to admit that I've never used the stuff, though I've heard good things about it.  Where did you get it locally?

post #564 of 5003

I ordered it here, but I'm not really sure where you could buy it locally. I think this stuff is the middle product they offer. You get two 1 ft x 1 ft panels, but you really could do with less. I've only used about 5% of the two panels.

post #565 of 5003
Some Internet hardwood stores have brazillian rosewood for sale.
post #566 of 5003

Any place that sells car audio should have dynamat or similar materials. A cheaper alternative that I've heard some car guys use is the stick on roofing shingle stuff. For headphone purposes though, the few bucks you spend on a dynamat sheet will last you forever.


Edited by Armaegis - 12/26/10 at 12:52pm
post #567 of 5003

Tar based vibration dampners, like roofing material, so far as I have read are not as effective as butyl based vibration dampners (dynamat, second skin, etc.), but I have no firsthand comparisons.

second skin (secondskinaudio.com) is cheaper than dynamat though, and is 100% butyl based its also black and not aluminum colored.

 

also, tar based barriers can smell, not always, but sometimes.

post #568 of 5003
Quote:
Originally Posted by Maverickmonk View Post

Tar based vibration dampners, like roofing material, so far as I have read are not as effective as butyl based vibration dampners (dynamat, second skin, etc.), but I have no firsthand comparisons.

second skin (secondskinaudio.com) is cheaper than dynamat though, and is 100% butyl based its also black and not aluminum colored.

 

also, tar based barriers can smell, not always, but sometimes.


Hmm. The pro version is 3 times as thick as the dynamat I have. I'd have to say that is too much of a good thing. It'd be overkill, IMO. I'm going to stack up 3 layers of dynamat and see if there is any difference sound wise.


Edited by BobSaysHi - 12/27/10 at 12:11am
post #569 of 5003

Well, I've had quite an unexpected result. The bass seems to me to have a better *thump* to it. It bass itself doesn't increase in volume, but the thump is not placebo either. At first I put my headphones on the wrong ears (by accident). I thought, "hmm it seems as though the other side has better bass." So I was about to take the dynamat off and claim it a failure, but then I realized the side with 3 layers of dynamat was the side with better bass. It's subtle, real subtle, but it's there. 

 

Anyone up for a group buy of Damplifier Pro? You only need like 3 square inches of the stuff for both drivers, it might be a good idea.

post #570 of 5003

Group buy? I don't think all the grado modders in the world would buy enough to lower the price. It'd be easier just for one guy to buy a couple sheets and mail out pieces.

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