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DCM TF600 question...

Copa1934

Copa1934

My ears are bleeding
I'm making new socks for a pair for a friend and I was wondering why there is a piece of felt behind the tweeter? My first thought is maybe to control vibration of the metal screens, but at the same time doesn't that impair the performance of the driver directly behind it?

I'll leave well enough alone if it's truly necessary, just wondering if anyone had experience removing the felt.
 
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Images

So, for those who still don't believe there is another woofer I submit the images you see. I'll post more as the "refurb" progresses along.

First note the tweeter moved aside to expose the woofer. Behind the tweeter is the felt I've mentioned here and in another post regarding the 600's.

You'll note one of the images shows the foam I'm using to replace, well whatever it was that may have qualified as foam at one time. Also, there is an image of the first "sock", which shows the top which is stitched together. Originally the inner sock was simply wrapped and glued into place. I didn't like this from a service point of view and that sticky crap all over, yuck! Anyway, I'll cut openings for the top and bottom pins later, once the test fit is completed.
 

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I don't think you will get any posts because none of this makes sense. What felt? I see no felt. The tweeter mounts in front of the woofer? Why? The cabinet is very thin yet the sock is over a wide something. Need much more info.
 
Bellair said:
I don't think you will get any posts because none of this makes sense. What felt? I see no felt. The tweeter mounts in front of the woofer? Why? The cabinet is very thin yet the sock is over a wide something. Need much more info.
Click to expand...
If you look at the shot of the tweeter (should have lightened the image up) you'll note you can only see through the mesh in the corners, that is because there is a felt like material (black in color, of course) that is sandwiched between the screens.

As for the sock, the speakers are tapered (assumption being you weren't aware of this). So one end will be wider than the other, though honestly I'm not sure what made you ask the question about the cabinet being thin. Anyway, the other sock will be designed for easier removal so the speakers can be serviced more easily, should they need any service down the road.

And why the tweeter is mounted in front of the woofer? Hell if I know the logic behind that. Definitely not for time alignment since the VC's are not lined up, though maybe it is so that the sound waves don't cross paths? Hopefully someone reading this will chime in, that knows more of course.
 
Thanks for the pics. I have had a pair of 600s for years but have avoided going inside for any reason. I have been in my 400s and they are similar, but no second woofer arrangement and no rear firing tweeters. I was careful of the sock and was able to keep the foam intact, though a bit crumbly.

My guess on the felt would be vibration dampening also.

Would you please take the time to describe the making of the new socks. Did you use the old material for a template to cut out? Where did you get the new material? Did you do the sewing yourself or did you have assistance? Was the sewing difficult or tricky in any way? Any comments on the procedure would be greatly appreciated. Thanks.
 
I guarantee that the felt has a sonic purpose, perhaps only one that could be heard by the designer and not easily measured. These speakers may not have the most expensive drivers, but I guarantee that they were lovingly designed.

Everything from the drivers to the crossover is non-standard and functional.
 
I took the felt that was under the metal screen off of one of mine when doing a repair and can't hear a difference between it and the other speaker. I'm sure it was there for a reason and when I resock them I'll put it back. I don't really try to disect or rationalize the design of my TF-600's....I just enjoy the hell out of them!
 
KingBubba said:
Thanks for the pics. I have had a pair of 600s for years but have avoided going inside for any reason. I have been in my 400s and they are similar, but no second woofer arrangement and no rear firing tweeters. I was careful of the sock and was able to keep the foam intact, though a bit crumbly.

My guess on the felt would be vibration dampening also.

Would you please take the time to describe the making of the new socks. Did you use the old material for a template to cut out? Where did you get the new material? Did you do the sewing yourself or did you have assistance? Was the sewing difficult or tricky in any way? Any comments on the procedure would be greatly appreciated. Thanks.
Click to expand...
I sell and repair sewing machines for a living, my father did it for 50 years. However, that by no means qualifies me as a sewer. I've managed to get by on simple repairs, altering a few pants, etc.

I picked up two types of material at JoAnns. The inner sock was as close as we, the sales person I know there, could find. For the outer they only had one "Speaker" cloth, yes it says on the bolt (what material is rolled on) "Speaker cloth". To my ears it appears acoustically transparent. OK, got my salesman cap on now. I used a Brother QC-1000 sewing machine and did all the work myself. I'll post detailed images if people really want to know. It's not a big deal, but it does make for a nicer "fit". The machine handled the stretchy material effortlessly, which of course makes for more fun than frustration. For those who really want to know, a Ball Point needle works best and is less likely to fray or damage the material. Oh, the method I'm using requires absolutely no adhesive!

Want more images? Let me know, I'm happy to oblige.

Enjoy!
 
js1138 said:
I guarantee that the felt has a sonic purpose, perhaps only one that could be heard by the designer and not easily measured. These speakers may not have the most expensive drivers, but I guarantee that they were lovingly designed.

Everything from the drivers to the crossover is non-standard and functional.
Click to expand...

Agreed - all of this stuff has a purpose, although I don't profess to understand much of the engineering behind it. DCM calls this mounting system an "anti-diffraction acoustic lens," and it appears to be a refinement of earlier approaches such as the pieces of felt that mask portions of the mid/woofers on earlier models like the TimeWindow 1A and TimePiece speakers.

Along with the coaxial mounting of the tweeter, the intent was to create a point source with wide dispersion characteristics. Throw the time-aligned crossover, transmission line woofer loading, mirror-imaged driver arrangement, and cabinet design into the equation, and you start to appreciate the complexity and innovative thinking behind this line of speakers. Of course, this would all be academic if they didn't sound so good and weren't such a great value. Good to see a growing number of people coming to appreciate this somewhat obscure brand.
 
Copa1934 said:
Want more images? Let me know, I'm happy to oblige.

Enjoy!
Click to expand...

Yes, please keep them coming! Many used Timeframes are in rough shape and need the kind of repair work you are doing. Since it's such a pain to disassemble Timeframes and get a look at the insides, you are doing everyone a service by documenting your work here.

Thanks for sharing!
 
CygnusDen said:
Agreed - all of this stuff has a purpose, although I don't profess to understand much of the engineering behind it. DCM calls this mounting system an "anti-diffraction acoustic lens," and it appears to be a refinement of earlier approaches such as the pieces of felt that mask portions of the mid/woofers on earlier models like the TimeWindow 1A and TimePiece speakers.

Along with the coaxial mounting of the tweeter, the intent was to create a point source with wide dispersion characteristics. Throw the time-aligned crossover, transmission line woofer loading, mirror-imaged driver arrangement, and cabinet design into the equation, and you start to appreciate the complexity and innovative thinking behind this line of speakers. Of course, this would all be academic if they didn't sound so good and weren't such a great value. Good to see a growing number of people coming to appreciate this somewhat obscure brand.
Click to expand...
My goal, above all else, is keeping these bugger in circulation and not becoming landfill fodder. Actually that applies to most of the speakers I encounter.
 
Thanks for the pics. I have never had the sock off of my 600's in part because there has been no need and in part because I don't want to risk damage to the sock.

Maybe it is just the pics taken but I don't see the rear firing tweeter that is a feature of the 600's.
 
Wolverine said:
Thanks for the pics. I have never had the sock off of my 600's in part because there has been no need and in part because I don't want to risk damage to the sock.

Maybe it is just the pics taken but I don't see the rear firing tweeter that is a feature of the 600's.
Click to expand...
Just front shots so far. I'll shoot the back when I cut the openings for all the drivers. One sucks as it wasn't installed correctly so I'll have to repair the opening and screw hole so the speaker is actually flush with the surface, like all the other rears (both sets).
 
Yes,we do indeed appreciate your instruction/pics.I too just might get the nerve to crack open my 600's and replace the socks properly.My feeble attempts are not documented via pics but I will do so once I figure out how to post said pics!The 600's are definitely worth the work.
 
phatster said:
Yes,we do indeed appreciate your instruction/pics.I too just might get the nerve to crack open my 600's and replace the socks properly.My feeble attempts are not documented via pics but I will do so once I figure out how to post said pics!The 600's are definitely worth the work.
Click to expand...
Just watched "Crossroads" last night, big Guitar fest in TX, hosted by Eric Clapton. ZZ-top closed the show. Fun DVD to watch and nicely engineered, especially if you have DTS!

I'll be posting more images later this week. Glad people are enjoying it, and I'm happy to post.
 
I am not familiar with DCM speakers but I do know the designer/owner. I can see now this is a sort of 2 1/2 way where the two woofers add at lower frequencies but only one does the upper mids going into the tweeter. Perhaps the felt is a mechanical crossover to eliminate the additional coil going to the second woofer. Are there two coils of different sizes?
 
Bellair said:
I am not familiar with DCM speakers but I do know the designer/owner. I can see now this is a sort of 2 1/2 way where the two woofers add at lower frequencies but only one does the upper mids going into the tweeter. Perhaps the felt is a mechanical crossover to eliminate the additional coil going to the second woofer. Are there two coils of different sizes?
Click to expand...

...Nevermind.
 
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