Ultrasone Proline 650 mods
Aug 18, 2007 at 6:05 AM Thread Starter Post #1 of 98

kwkarth

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A little background..
It's been a while since I had mixed a live concert for recording or sound reinforcement and I was asked by a friend a couple weeks ago to do that for a gig where there would be four bands, each with completely different mic requirements and set ups. I had never even met any of the musicians in the four bands except for the pianist who had invited me to help. After having read so many things here about the Ultrasone cans and how good they all were, I decided I had a perfect excuse to buy a pair of Ultrasones to see how they would do as monitoring cans. I set my sights on the Pro-650s because the local Guitar Center had them in stock (and none of the other ProLine series.) and because some of the reviews I had read on the web indicated that many liked the 650s over the 750s.

OK, so I picked up a pair on my lunch hour and took them back to the office to give them a listen because I couldn't wait to hear them until I got home in the evening. I work for myself anyway, so I justified it...
wink.gif


Anyway, long story short, they were a BIG disappointment out of the box. The demo pair sounded good to my ears with their demo material at the store, but I had not listened to them with any material I was familiar with.

Compared to my K701s, both cans being driven by my RSA SR-71, the K701 sounded its usual glorious self, but the 650 had a honky, hollow coloration in the upper mids that drove me batty. I also noticed that they didn't isolate very well at all.

So then I thought I would give them some burn in before the gig and try them anyway for the mix down, then about 4 days away. I put them in my office at home plugged into a little TEAC receiver set to an FM station playing jazz a little louder than I would normally listen. They ran 24/7 for those 4 days. At the end of that burn in, they had improved a little tonally, but of course, the isolation hadn't changed, nor did I expect it to. They were still not near accurate/neutral enough to use to set mix levels for a band, but I brought them to the gig anyway along with my trusted Beyer DT-250-80s and ETY ER-4P/S. About 10 seconds of listening in the live gig was all I needed to determine that they were useless for that purpose. I reverted back to my trusty DT-250s, and completed the job with the Beyers.

Later, back at the ranch...

I was seriously considering selling them, but also curious to know if they could be improved. I was considering opening up the vents on them like the 2500s since it was only a couple pieces of plastic making them "sealed" covering the vents.

I opened up one side of the 650s one morning before I left the house. There was what looked like a black plastic ring glued over the vents that are visible from the outside on the 2500s. Rather than remove that ring, I decided first to try adding some acoustic and vibrational damping material to the inside of the ear cup because it was totally empty in there, stock!

I decided to use a layered approach to tame all audio frequencies. I used a mechanical damping material for the plastic ear cup itself, (Dynamat) and a layered sandwich of heavy wool felt, heavy polyester felt, and a fabric backed poly foam.

If you're at all familiar with the "putty" they use to install automotive windshields, this Dynamat stuff looks and feels like that with a layer of lead foil (but it's not lead) laminated to the gooey sticky stuff. It has a great "thud" factor. (In other words, you can stick even a little bit of this stuff to something that rings like a bell, and after you put that stuff on it, it doesn't ring any more, it just goes "thud" when you thump it.

So, the ear cups were opened up and measured. I cut a 7cm circles of the Dynamat, the wool felt, the Poly felt, and the foam backed fabric. I applied the Dynamat directly to the inside of the ear-cup shells, then layered the fabric backed foam on top of the Dynamat, then the wool felt, then the poly felt. The driver and baffle board were then mounted back into the shells on top of the damping sandwich. See pictures below:

Before the operation:
1155926536_9c6f3930a8.jpg


With the earpad removed.
1155081151_97bcf51bc7.jpg


Next, remove the four screws that hold the baffle board to the shell.
1155088809_c73b9dd65b.jpg


Here's a picture of the back of the driver up close just for grins
1155095645_9159f76628.jpg


Cutting out a piece of the felt.
1155924788_ac8cace55c.jpg


Felt, up close and personal:
1155148915_77c1d356de.jpg


Here's a picture of the pkg that the Dynamat came in:
The felt and the foam totaled about 10 bux, but the Dynamat, for two lousy pieces, was about $25.
1155102837_171d3272a9.jpg


Here's a sheet of the stuff:
1155968496_225c35cb1f.jpg


Here's the 7cm circle cut out:
1155109677_7ac8c20d8e.jpg


Laying it in the cup to check the fit.
1155125779_b812bf3163.jpg


Next, make notches in it for the obstructions, peel off the paper backing and adhere it to the ear cup. Press it in reeeel good.
1155133701_24693e9713.jpg

1155992910_4c8c807073.jpg


Acoustic damping material, fabric, foam, wool felt, poly felt.
1155175191_852e07d48a.jpg


Here's the acoustic sandwich before I layed it in the cup.
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I bet you're wondering how they sound??

You wouldn't recognize them. They sound very impressive now! I could do a mixdown with these babies! Much more neutral. Bass extension is better, midrange coloration is gone, highs are sweet and extended with no more stridency.

They isolate the ambient room noise at least 10db better than before.

I'm going to have to live with these for a while to make sure I'm not fooling myself, but man! This worked far better than I ever expected!

Has anyone else tried this mod?
 
Aug 18, 2007 at 6:35 AM Post #2 of 98

1Time

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Very impressive. I've used Dynamat and similar sound deadening materials including "Peel and Seal" inside loudspeakers and my car, but never thought to use it in headphones.

What you've done seems like an upscale version of the blu-tak mod used on the HD280. I particularly like your layering of 4 different materials. And I find it quite remarkable that you improved the Proline 650 so much and got just what you wanted out it with this mod.

As much as I enjoyed my Proline 650 when I had it, you may have just given me reason enough to buy it again. Thanks
 
Aug 18, 2007 at 7:26 AM Post #3 of 98

Contrastique

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Nice work, Kwkarth! Didn't expected it to be so much of a differ. Glad to see you like them now! Keep us posted with changes into your perception of the sound.
 
Aug 18, 2007 at 9:51 AM Post #4 of 98

stevenkelby

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Very nice job. I use that self adhesive bitumen mat stuff everywhere. It's the same as dynamat but I get it locally. Filled up my car and PC with is, great stuff.

Are you going to remove a bit of stuff to change the sound or leave it how it is?
 
Aug 18, 2007 at 12:30 PM Post #6 of 98

jpelg

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Nice work, k!

How did you come up with that particular recipe? Did you try different combinations before coming up with your final combo?
 
Aug 18, 2007 at 4:38 PM Post #8 of 98

kwkarth

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Quote:

Originally Posted by 1Time /img/forum/go_quote.gif
Very impressive. I've used Dynamat and similar sound deadening materials including "Peel and Seal" inside loudspeakers and my car, but never thought to use it in headphones.

What you've done seems like an upscale version of the blu-tak mod used on the HD280. I particularly like your layering of 4 different materials. And I find it quite remarkable that you improved the Proline 650 so much and got just what you wanted out it with this mod.

As much as I enjoyed my Proline 650 when I had it, you may have just given me reason enough to buy it again. Thanks



I actually did a little looking around for some blu-tak, but all I could find was Elmer's Tack which is similar, but after consideration, the dynamat intuitively seemed to be much more effective.

I actually got the idea originally from Joe Grado himself. When he was still actively involved in his business, right after he brought the very first Grado hedphones to market, I drooled big time over the HP-1s and 2s but couldn't afford them at the time. I ended up hand picking a pair of SR-200s that visually, had the same drivers in them as the HP-1/2s. They sounded really good, but obviously not as good as the top of the line.

I don't remember why exactly I called, but I called Grado about something and ended up talking to Joe himself. I'l bet we spent at least half an hour on the phone, maybe more. Anyway he told me about all sorts of things I could do to the 200s to improve their sound and comfort. Most of the mods had to do with vibration and mechanical damping of the headphone frame. It made a world of difference. Ever since then, I've looked at all headphones for ways to improve them in those areas, since it helps so much with the sound.

I used to design and build speakers in the old days, and had experimented with many different materials for sound absorption inside the cabinets and on the outside to minimize surface effect diffraction. I also designed some acoustic panels used architecturally to control sound reflections in large halls.

Anyway, my mods on the 650 were an amalgam of all that previous stuff.
My choice of the particular materials I employed here were dictated by what was available as well. I would have preferred to use an even denser/heavier wool felt, but could not find it in the little time I allocated for the project.
 
Aug 18, 2007 at 4:52 PM Post #9 of 98

kwkarth

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Quote:

Originally Posted by Contrastique /img/forum/go_quote.gif
Nice work, Kwkarth! Didn't expected it to be so much of a differ. Glad to see you like them now! Keep us posted with changes into your perception of the sound.


Thanks. I too, did not expect to find such a significant difference in the sound.

In retrospect, the construction of, and materials used in the 650s allowed a great deal of internal vibration/reflection to muddy the sound to the point where it actually ruined the midrange for me.

They were pretty much unlistenable to my ears for that reason. Because they did not isolate well at all, they were also useless in any sort of a live venue even if I could have put up with the midrange mess.

As it is now, with the mods, they sound quite pleasing, and even exciting to listen to, and they isolate better than my Beyer DT-250s, so I am quite pleased with the results thus far.

Their sound signature is different from any other can I have. The Beyers are slightly warm in the 250Hz region by comparison to the ProLines. The Prolines are very, very, very detailed and quick sounding, the Beyers, much slower and less extended. They both sound good however.

Vocals, pianos, and woodwinds were unlistenable on the un modded 650s. Now they're quite pleasant to listen to. Pipe organs are awe inspiring on the modded 650s.
 
Aug 18, 2007 at 4:54 PM Post #10 of 98

kwkarth

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Quote:

Originally Posted by stevenkelby /img/forum/go_quote.gif
Very nice job. I use that self adhesive bitumen mat stuff everywhere. It's the same as dynamat but I get it locally. Filled up my car and PC with is, great stuff.

Are you going to remove a bit of stuff to change the sound or leave it how it is?



I may remove one of the layers to see what changes it produces, but for now, I think I'll just observe/listen to them for a while to see if any other ideas pop into my head.
 
Aug 18, 2007 at 4:57 PM Post #11 of 98

kwkarth

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Quote:

Originally Posted by Dexdexter /img/forum/go_quote.gif
Lovely work, kw!
650prolinetl7.png


Looking forward to your continuing impressions. I'm tempted to try just the acoustic sandwich part and see what it does before committing myself to the Dynamat, which looks like it could be sticky business to remove...



Yes, the dynamat is sticky, but I think it would be removable. The adhesive properties do not seem to be permanent and I think that it helps quite a bit in the case of the 650s. I would do exactly what you suggest first though. Good luck!
 
Aug 18, 2007 at 4:57 PM Post #12 of 98

jpelg

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1155095645_9159f76628.jpg


It looks like those diodes are perilously close to shorting the main cable leads. Did you secure them down with that yellow tape?

1155133701_24693e9713.jpg


Anyone know what those diodes actually do?
 
Aug 18, 2007 at 5:00 PM Post #13 of 98

kwkarth

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Quote:

Originally Posted by jpelg /img/forum/go_quote.gif
Nice work, k!

How did you come up with that particular recipe? Did you try different combinations before coming up with your final combo?



Thanks j. This was an educated guess, shoot from the hip, shotgun approach.

So, no, I didn't try different combos first, but I may play with the mix later on after some more observation.
 
Aug 18, 2007 at 5:05 PM Post #14 of 98

kwkarth

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Quote:

Originally Posted by jpelg /img/forum/go_quote.gif
1155095645_9159f76628.jpg


It looks like those diodes are perilously close to shorting the main cable leads. Did you secure them down with that yellow tape?

Anyone know what those diodes actually do?



Yes, I insulated the leads of the diodes from potential shorting from the leads. The leads are protected with enamel on the wire, but that's very thin and I didn't want to have potential for problems later on.

The purpose of the diodes is for overload protection for the drivers. Their forward conduction threshold is higher than any sane person would listen. If that threshold is exceeded, they conduct and short the signal above the threshold, thus protecting the driver from burn out. Arguably, they may have a minor effect on small signal performance, but I don't think so. In any event I may open that up at some point and see if there's any audible difference.
 
Aug 18, 2007 at 5:11 PM Post #15 of 98

kwkarth

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Quote:

Originally Posted by GreatDane /img/forum/go_quote.gif
Great info/pics on your mod. I plan to buy the 750 and wonder how this mod would effect them. Probably in a very similar way??


Good question! Since I've never laid eyes on the 750s, I don't know how they're constructed. Visually, the shell looks the same from pictures, but I can't really tell anything from pictures alone. Once you get your 750s, why don't you take a look inside and give 'em a listen to see what you've got to work with, then you'll have a better idea if there's anything you can do to improve them.
 

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