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SR60-Mod - Page 36  

post #526 of 5003

This is the first attempt i could call successful. They are Red Oak, and are 2 boards thick. I found a solution to the glue-drip problem, I glued the boards together before I drilled them. They are 2 1/2" outer diameter, but I did something interesting with the inner diameter. I drilled most of the inner diameter to 1 7/8", and only drilled the back, about 3/8" in, as 2". Not only does this give a wider ring on the outside of the donut, but it also means that the inner wall is flush between the oak and the plastic (because the plastic sits in the wider part, making it equal to the narrow part). Also, this means that the drivers don't sit flush, leaving the stock "groove" available too securly mount the pads. All thats left is to wire them, and stain them (and sand them, a lot more than they are now)

 

1221101230.jpg

post #527 of 5003

 

Quote:
If the magnetic force of this additional magnet were to pass even somewhat through the Mumetal back plate (I think it's Mumetal) it would shift the stock magnet's center of field closer to the back plate.

 

 

You are correct that adding a magnet would shift the overall magnetic centre away, but in terms of overall effect the voice coil should be seeing a stronger magnetic field. Look at it as two superimposed fields rather than a combined one. The original one doesn't change, we're just sticking another field on top. However, this second field is at a further distance, and since field strength is a squared relation with distance, it might have a negligible effect compared to the first.

 

 

Quote:
That would cause the voice coil to be in closer proximity to the plate due to the shifted magnetic field and the voice coil end might slam into the plate during high excursions. The diaphragm/suspension would also be stretched rearward beyond normal

 

I don't think so. Without signal applied, the voicecoil just sits there at neutral. Once you pass a signal though, you *should* get a stronger response (both ways) in the coil if your magnets are stronger, although you'll also need some more juice in your amp to drive it.

 

 

Granted, I'm just talking through my understanding of physics here. There's a bajillion things regarding headphones design I don't know yet.

post #528 of 5003
Thread Starter 

 

Originally Posted by VinylCat62 View Post



Quote:
Originally Posted by Bilavideo View Post

 

Originally Posted by VinylCat62 View Post

Oh, and I wouldn't recommend adding another magnet to the back plate for damping or otherwise. If the magnetic force of this additional magnet were to pass even somewhat through the Mumetal back plate (I think it's Mumetal) it would shift the stock magnet's center of field closer to the back plate. That would cause the voice coil to be in closer proximity to the plate due to the shifted magnetic field and the voice coil end might slam into the plate during high excursions. The diaphragm/suspension would also be stretched rearward beyond normal.


Before reading this, I tried it on a whim.  It didn't have any effect I could hear.


Ah...I see...OK. Guess that shield is doing a better job than I thought it could. Or the external magnet you tried wasn't of sufficient strength. Or it still wasn't in close enough proximity to the voice coil. Or both, or ???. I wonder what would happen if you added a couple more magnets to the back plate, one on top the other?

 

Or perhaps I'm all wrong on this. Do you know if that external magnet sticks to the rear backside of the plate even without the stock magnet in place? I mean is the plate all by itself magnetic even on the rear backside?


I don't think the plate, itself, is magnetic but magnets stick to it.  The magnet in the plate is held there by magnetic force.  The identical type of magnet stuck to the back of it by magnetic force.  I didn't have to have a magnet in the plate to stick another magnet to the back of it.

post #529 of 5003
Thread Starter 

 

1221101230.jpg

 

Nice job, Maverickmonk!  It took me a while to find a set of solutions that fit all of my needs.  You did a nice job of getting the shell within the parameters needed to fit the hooks.  If you're looking to slide a plastic front into these, you should be in good shape.  If you cut window screen a little larger than the rear hole and then taper the ends all around, you'll be able to slide a rear screen in, one that won't need an additional ring to hold it in place.  The beauty of window screening is that it's bendable.  I like the thickness of your walls as well as the clean cut you performed.  I think you did a great job.


Edited by Bilavideo - 12/22/10 at 8:46pm
post #530 of 5003
Quote:
Originally Posted by Armaegis View Post

 

Quote:
If the magnetic force of this additional magnet were to pass even somewhat through the Mumetal back plate (I think it's Mumetal) it would shift the stock magnet's center of field closer to the back plate.

 

 

You are correct that adding a magnet would shift the overall magnetic centre away, but in terms of overall effect the voice coil should be seeing a stronger magnetic field. Look at it as two superimposed fields rather than a combined one. The original one doesn't change, we're just sticking another field on top. However, this second field is at a further distance, and since field strength is a squared relation with distance, it might have a negligible effect compared to the first.

 

 

Quote:
That would cause the voice coil to be in closer proximity to the plate due to the shifted magnetic field and the voice coil end might slam into the plate during high excursions. The diaphragm/suspension would also be stretched rearward beyond normal

 

I don't think so. Without signal applied, the voicecoil just sits there at neutral. Once you pass a signal though, you *should* get a stronger response (both ways) in the coil if your magnets are stronger, although you'll also need some more juice in your amp to drive it.

 

 

Granted, I'm just talking through my understanding of physics here. There's a bajillion things regarding headphones design I don't know yet.


There's a bajillion things I also still need to learn too. But I did some more checking and you're right. I found this link that asks the same thing about woofers > http://www.tomshardware.com/forum/39120-6-stupid-speaker-magnet-question  It seems it would have to be several magnets of high gauss to have any displacement effects on the Grado voice coil whether with an applied signal or not. So just one magnet stuck on the back plate shouldn't be a problem at all. And based on what Bilavideo just said I don't think the plate is made of Mumetal either, or at least of a Mumetal of any substantial magnetic resistance. That seems to indicate the metal plate might be acting as a combined poleplate. I hadn't thought that possible without an actual pole piece, but there ya go...Grado, you, and Bill, have again taught me something new. Sorry for the little distraction...now, back to the show. Cheers.


Edited by VinylCat62 - 12/21/10 at 12:42pm
post #531 of 5003

Shells were from the master, here are my modded SR60s (: The cable sleeving is some cheap-feeling and cheap-looking mesh because I couldn't get my hands on techflex, but at least it lets my SPC braid show through :D

DSC08256.JPG:DSC08255.JPG


Edited by Nightslayer - 12/22/10 at 8:02pm
post #532 of 5003
Thread Starter 

Well done!  That's a sharp setup!

post #533 of 5003
Quote:
Originally Posted by Nightslayer View Post

Shells were from the master, here are my modded SR60s (: The cable sleeving is some cheap-feeling and cheap-looking mesh because I couldn't get my hands on techflex, but at least it lets my SPC braid show through :D

DSC08256.JPG:DSC08255.JPG


I'm interested to hear your sound impressions. I'll be doing pretty much the exact same thing you are, and I'm interested in how you think they sound.

post #534 of 5003

Great work! I have been wanting to do that for a long time now. Too bad my brother keeps nicking my beloved MS1000. ;-)

post #535 of 5003

Well. After hearing this I've clean forgotten a lot of the SR60's faults, which weren't completely obvious to me stock because I have a thing for organic natural sounding phones. Anyway the drivers have been vented as well, ten holes on one and four on the other due to a previous imbalance which has been corrected but I haven't bothered to cover up the driver vents now. But as it is the bass is both present in volume as well as impact. There is a marked cleanliness to the sound which may be placebo but I'm hoping it isn't (: Separation which has already been good has improved, there is now a marked space between a lot of instruments. Soundstaging is roughly the same, retaining the inside-the-head sound, sadly.

 

The below test tracks are in Apple Lossless converted from flac, though I personally believe anything above 256kbps VBR is perfectly satisfactory. I shall try to do my first ever headphone review (:

 

Nightwish, Once: Ghost Love Score

Drum texture is excellent, the bass drum shines through but doesn't overpower everything. The crashes are a tad bit thin, though. Brasses are clean and sharp, which treble-adverse people might shirk from though I suspect they might have been veiled just a bit since the stock. Separation is good until the entrance of the distortion guitars, which considerably muddies up the track. An overall imbalance to the bass frequencies is present though, I will look towards covering up some of those holes in my driver felt. Strings can be heard distinctly but not as individual instruments, though I suspect that might be the recording's fault since I hear roughly that on my analytical DBAs. Voice is very full-bodied, but lacks an edge which makes it sound slightly unnatural.

 

The London Symphony and London Voices, Star Wars Episode 1 Soundtrack: Duel Of The Fates

My favourite audition track, the choir voices are very nicely separated and can be individually heard in the opening chorus, though the track is rather echo-y, which I suspect might be due to the recording hall. The headphone itself somehow doesn't manage to keep up with the speed required for orchestral tracks, though the texture of every instrument is nicely presented, down from the ostinato in the strings to the motifs in the brass to the rolling of the timpanis. The general "body" in the instrument sounds is present, which colours the overall tone very nicely imo. On the overall the track is rather to my tastes.

 

Muse, HAARP - Live at Wembley Stadium: Butterflies and Hurricanes

In my humble opinion, the above song is the best they've ever written, discounting the lyrics. I really can't figure out whether the lack of a natural raw tone in voices is a result of track mixing or imperfections in my headphones, but either way it's not present, though Bellamy's breathy voice sounds as good as it does live. Excellent separation once again, which is impressive in a track like this. The tinkling drum ride has just that tad bit of body which keeps it from sounding unnaturally tinny, and the snare sounds great, for lack of a better descriptive. Individual notes in the bass guitar can be picked out easily, and the guitar sounds consistent over the entire tonal range. The piano sounds rather thin though, but I suspect that might be the fault of the Kawai. Soundstaging is unfortunately very in the head and up front though.

 

Edit: I'm listening to the Handel-Halvorsen Passacaglia by Perlmann and Zukermann, and I'm sad to report the headphones do cut off a slight edge (e.g. a bit of the the bite of the bow on the strings), which gives the sound a very smooth tone but may not be satisfactory to those looking for every last detail.


Edited by Nightslayer - 12/23/10 at 4:49am
post #536 of 5003
Thread Starter 

Very cool review!  Have you tried pad-swapping?  The comfies mute the HF, which seems to come up again and again.  While the jumbos will give you the most soundstage, I'd be interested in hearing how things are different as you switch to bowls.

post #537 of 5003

I have bowls but they somehow don't fit very well and they aren't as big as jumbos, so I'm using the quarter mod for the timebeing. Will try out your suggestion though (:

post #538 of 5003
Thread Starter 

I've got wood!  Tonewood, that is!

 

Photo on 2010-12-23 at 14.39.jpg

 

I found a supplier about ten miles from my home who has a supply of mahogany.  If I had a lathe, I'd have kept this block together, but seeing I just have the drill press, I had him cut the mahogany into one-inch sheets.  

 

Photo on 2010-12-23 at 14.38 #3.jpg

 

Later today, I'm going to hit Tampa to find another supplier.  I'm hoping this place will have some more tonewoods.  I've really got a craving for brazilian rosewood, but since buying it is like clubbing baby seals, I'm going to see if I can get the next best thing.  I'm psyched!


Edited by Bilavideo - 12/24/10 at 11:02am
post #539 of 5003
Thread Starter 

Photo on 2010-12-24 at 13.10.jpg

 

The mahogany cutting has begun.  I like what I see - and hear.  Compared to the poplar and red oak I've been using, mahogany cuts cleaner.  It leaves a chocolatey sawdust that's richer than the other stuff but, for whatever reason, it leaves a cleaner edge to it.  I like that.  All of the rings I'm showing you have yet to be sanded.  That's pretty good right off the drill press.

 

Photo on 2010-12-24 at 13.11.jpg

 

The sheets I got cut were a little wider than what I'm used to (by about a quarter of an inch) but the length of a single ring is more than adequate for a slip-on shell.  

 

Photo on 2010-12-24 at 13.11 #2.jpg

 

I haven't glued this in yet because it still needs to be sanded.  I haven't decided yet whether to add a coat of lacquer, as I'm not sure what effect the lacquer will have on the sound.

 

Photo on 2010-12-24 at 13.23.jpg

 

For those who are looking for a sound improvement, with a low profile, these single rings seem like a good idea.  It's simplicity itself.

 

Photo on 2010-12-24 at 13.24.jpg

 

It looks like I scorched a ring.  There's plenty of room for improvement in my woodworking skills.

 

Photo on 2010-12-24 at 13.35.jpg

 

I need to make some thicker rings, like these red oaks.  If I do, I'll have a little bit of hammerhead action working in mahogany.

 

Photo on 2010-12-24 at 13.35 #3.jpg

 

Doing so produces more than enough volume in an air chamber that doesn't look like Frankenstein's bolts.

 

Photo on 2010-12-24 at 13.35 #2.jpg

 

Well, I'm off to do that last little bit of shopping before the iron grate comes down on Christmas.  Next week, I have an appointment with a man who deals in cocobolo, a tonewood so robust it's being compared to Brazilian rosewood.  Happy holidays to all!

 

Oh, P.S.  I actually listened to the new rings.  Even with a minimal setup, it's obvious why mahogany is a "tonewood."  The shells, themselves, vibrate like an extension of the drivers.  In the process, the cushions are doing what I always suspected the Grado cushions were intended to do: impart vibrations to the earlobes to give a greater sense of impact.  Next week, I hope to find out what cocobolo can do.

 

Photo on 2010-12-24 at 13.46 #3.jpg


Edited by Bilavideo - 12/24/10 at 11:05am
post #540 of 5003

I am beginning to suspect that this thread is really about Bill taking pictures of himself biggrin.gif (also, quick! someone get this man a comb for Christmas!)

 

Wouldn't holding the shells with your fingers affect the sound? Perhaps not as pronounced as mechanically coupling the drivers, but it's still removing vibrations.

 

As for wood treatment, I started thinking about stringed instruments and what their makers use. Apparently I have a lot of reading to do... here's a couple samples off google:

http://www.gussetviolins.com/varnish.htm

http://www.violins.ca/varnish/violin_varnish_recipes.html

http://www.leroydouglasviolins.com/varnish.htm

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