Has there ever been a dome tweeter constructed of paper?

Paper/cellulose is still used in many low & mid frequency drivers to this day, as far as I know because of its lightness, stiffness and (some) inherent damping abilities. And paper cone tweeters, the best ones anyway, can sound quite good I think, though obviously not the equal of a modern dome especially as far as dispersion is concerned.

But does anyone know why paper has never been used in a dome configuration? I have never seen one myself. Is it something to do with physics or a manufacturing problem, or could it be a marketing issue, in other words, paper would be perceived as "cheap"?
 
Paper/cellulose is still used in many low & mid frequency drivers to this day, as far as I know because of its lightness, stiffness and (some) inherent damping abilities. And paper cone tweeters, the best ones anyway, can sound quite good I think, though obviously not the equal of a modern dome especially as far as dispersion is concerned.

I don't necessarily agree with you on the last comment (but then i'm not a big fan of the standard conves dome). The original EPI concave dome was made of paper. It is quite a nice tweeter (not well built thou). And there are more than a few that are essentually dome tweeters with big surrounds (the Large Advent) I have seen dome mids (Philips) and dome woofers (Foster)

dave
 
Yep- Philips AD0210 heritage was either a hard-felt or a paper blend.

Cerwin Vega had some dome-woofer prototypes built quite a while back, but never went into production. I believe they were a non-pressed-pulp material not unlike a lot of woofer cones:

[IMGDEAD]https://i18.photobucket.com/albums/b117/wolf_teeth_speaker/domewoofers-Herb.jpg[/IMGDEAD]

It's a 6.5" diameter dome.
Later,
Wolf
 
I pressed the pulp slurry into a dome shaped pan using an additional, identical pan for pressing to make a dust cap. Then put in the oven at 250 until they were dry/hard. Oh, and if I remember correctly I used a little Elmer's glue in the slurry. I never got them to work out as pretty as I'd hope, so I ended up using paper and cutting slits it to make something a bit more conical shaped. To do the slurry method for a tweeter would take a lot more precision then I was ever willing to go for.

Dan
 
According to Paper - Wikipedia: "In papermaking a dilute suspension of fibers in water is drained through a screen, so that a mat of randomly interwoven fibers is laid down."

I guess if you use a dome shaped screen (like a tea strainer), you get a dome shaped piece of paper.
Well I should've mentioned that you can do that for any shape of paper, but do you get the required stiffness that way?
 
I don't necessarily agree with you on the last comment (but then i'm not a big fan of the standard conves dome).
I've always wondered why concave domes never gained much popularity.
The original EPI concave dome was made of paper.
I did not know that - it's difficult to tell from the grainy pics I've seen of their old brochures.
It is quite a nice tweeter (not well built thou).
I've noticed many respected manufacturers use drivers that looked like they were built to be ugly as possible!
And there are more than a few that are essentually dome tweeters with big surrounds (the Large Advent).....
I've noticed the use of very large rolled surrounds appearing on more & more modern dome drivers, like Vifa's NE25VTS-04 tweeter that I'm considering using. So large in fact I wonder if the surround does more than just support the dome........


How do you form paper into a dome?
Actually I would think forming a piece of cloth, which is usually made up of fibers laying at ninety-degree angles to each other, into a circular dome shape would be more complicated.

Those CV dome woofers look wild - I wonder how they sound?

A couple years ago I had a pair of Acoustic Research AR3's. They had a small paper dome tweeter, which was renowned for its sweetness. The weird thing about it was its very low efficiency, which was around 82 dB/W.
2nd paper dome I now know about - I'm glad I joined the forum. :)

As far as the efficiency issue, based on experience with AR speakers I have a strong feeling that was an intentional design decision by AR engineers, and had nothing to do with choice of radiating surface material (hint: large woofers using a heavy paper+felt cone operating in a relatively small sealed cabinet aren't exactly a "green" bass reproduction system :)). There's a reason so many people use the words "warm" or "laid back" to describe vintage ARs.

I pressed the pulp slurry into a dome shaped pan using an additional.......
I'm just totally impressed by the fact you even TRIED to make a paper dome! :superman:

The closest I got to making my own electronic gear is when I checked out a DIY electronics book from a local library as a kid in the 70s. It had all kinds of cool circuits to build and one was an AM radio that needed a certain type of capacitor.....and the author provided the instructions on how to actually build that capacitor from scratch (this is when I finally looked at the book's copyright date and saw that it was something like 1946 :eek:). IIRC it basically consisted of 2" x 4" interleaved sheets of paper and aluminum foil, which I dutifully put together, but ran out of $$ and patience to finish the project so never found out if my homemade cap actually worked.
 
I've always wondered why concave domes never gained much popularity.

Focal -- JMLabs is the largest selling French speaker brand in the world and they all come with concave domes.

There is also a vintge 3/4" Foster that is nice.

it's difficult to tell from the grainy pics I've seen of their old brochures.

I should have some good pictures downstairs.

dave
 
snip
I'm just totally impressed by the fact you even TRIED to make a paper dome! :superman:

The closest I got to making my own electronic gear is when I checked out a DIY electronics book from a local library as a kid in the 70s. It had all kinds of cool circuits to build and one was an AM radio that needed a certain type of capacitor.....and the author provided the instructions on how to actually build that capacitor from scratch (this is when I finally looked at the book's copyright date and saw that it was something like 1946 :eek:). IIRC it basically consisted of 2" x 4" interleaved sheets of paper and aluminum foil, which I dutifully put together, but ran out of $$ and patience to finish the project so never found out if my homemade cap actually worked.

You don't even want to know what I'm doing now. Far more ambitious, radical, and possibly bizarre.:Ouch: I have more respect for process engineers now.

Dan
 
I've always wondered why concave domes never gained much popularity.

I think the main reason is that it complicates the magnet structure. If the dome is concave then you have to cut down into the core pole, or have a hollow pole, both of which eat into maximum flux. The convex dome is likely to have a greater rear volume and lower resonance. Also, the performance is about the same so why do it? (I'm not buying that the dispersion is better.)

All the AR domes of a period of 60s to mid 70 where paper, but the fabric domes turned out to be lighter, so they became the norm.

It is a felted paper process. You suck a slurry (particles and a binder suspended in water) through a shaped screen. This is how virtually all cones and dustcaps are formed also, and why you may see the pattern of a screen on one sde of a cone. Some are dryed on the screen and others are forced between two surfaces, giving a smoother outside look.

David
 
You don't even want to know what I'm doing now. Far more ambitious, radical, and possibly bizarre.:Ouch: I have more respect for process engineers now.

Dan
If we see news reports of an aurora borealis above a house in California, just one house, we'll know your project really was extra-special. :hypno1::p

I think the main reason is that it complicates the magnet structure.......
Makes sense (appreciate the details about how problems could happen). I guess Focal and the few other advocates of that design have found ways around the problems or figured the advantages were worth the problems it caused at the same time.
 
Paper cone EPI tweeter

dave
 

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What kind of process? I'm involved in personal care/cosmetics production, myself.

Right now I'm doing plaster casting of odd/irregular shapes(long story). Making the accurate molds and the quantity of plaster fast enough by myself has taken quite a bit of effort and an efficient process was necessary d/t the required strength and fast setting time. It's the material I've settled on for the product mostly for cost and quality/precision is good enough for what I'm doing. Any sort of process engineering is admirable IMO. What it takes to make an accurate , quality reproduction over and over again, each usably identical is really no small feet especially if it's relatively large or complex and requires precision. I never found it all that interesting until I tried casting/mould making myself. With the materials I'm presently using, I just got it down but never got the paper process to work particularly well. IOW not particularly repeatable. Certainly not enough to make a set of speaker cones/domes. In fact it seems paper must be a fairly difficult material to produce with precision esp complex shapes. I respect the heck out of what you guys do. Several of my family members/friends are in engineering and I never got too into the process guys' jobs. I found a new respect for it and I've never done anything very complicated like you chemistry guys do. Good chance the wife's got a jar of goo from you.:eek: One cousin complains about the difficulty of making precise polymers--I thought they were more precise in speaker cones than paper.:confused: He used to do metallurgy though and perhaps that's his 'issue'. Well over my head, but interesting none the less.

No one saw this in the Bay Area when I started this project?
Russell1.jpg


Dan:)