I doubt you are going to find one satisfying answer.
Larger drivers just went slightly out of fashion in the sixties.
Another factor could be "specmanship" in that an all paperdriver looks cheaper to the naive.
Paper is often associated with cheap to the common man. I often hear prols talking derogatory about paper drivers. As in "it only had paper drivers". Obviously being oblivious to the fact that most of the time paper is the best and most time honoured material.
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The thinner corrugated surround you describe is a different medium from the rest of the cone. The word 'medium' describes more than just the material (e.g. paper), but includes density, which will be smaller in the surround.
Even when waves enter a medium of lower density some of the energy is transmitted into the new medium and some is reflected back.
I'm surprised some of the full-range experts haven't joined in by now! 🙂
Even when waves enter a medium of lower density some of the energy is transmitted into the new medium and some is reflected back.
I'm surprised some of the full-range experts haven't joined in by now! 🙂
I count six question marks in your first post. Would you care to prioritise them?
So I've exposed myself as not being one‽ ;-)
Most drivers are actually equal density all over. A few higher and one differentiates between different parts. But "normally" ridges are pressed into the moist paper to compact and crease hinge it.
A few, normally high end drivers actually have a seam from edge to to dustcap where a fan shaped cardboard piece has been joined, to make a cone shape.
This is supposedly because a large flat piece can be made more even and hard.
All of those question I find relevant to the topic, the most important is the one in the title - why was the paper surround abandoned? for fullrangers that is...
Were they "invented", or just a part of early cone design to provide flexibility where it was needed?
Oops! I meant some of the other full-range experts.🙂 I certainly don't count myself as one!
Good question! The first moving coil invention dates back to the Ernst Wermer patent of 1877
However, the first recognisable moving coil speaker was the Rice-Kellogg of 1925 which actually had a rubber surround (see attachment).
In succeeding years, loudspeakers had leather surrounds before progressing to corrugated paper surrounds. The change from leather surrounds to moulded corrugations was an important factor in reducing the cost of production and brought about the large-scale adoption of the moving coil driver.
The effect on quality of reproduction was more questionable as the apparent increase in volume was due to increased resonance, and much of the true bass was lost due by stiffness in the suspension.
(Historical information obtained from 'Loudspeakers' by Gilbert Briggs.)
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FWIW I make my own Musical Instrument speakers, for Bass I use foam surrounds and matching heavier cones to reach low, same as gebneral woofer practice, but I have been very successful with paper edge 12" and 15" speakers.
When played side by side along standard (typically cloth edge) Bass speakers "they" reach deeper, but when extra "noise" is introduced (Drummers or Guitar Players) "theirs" dissappear or lose lots of presence , while "mine" cut through like a knife, always present in the mix.
The thin light easy to break up cone associated with integral paper edge plays a great role there.
When played side by side along standard (typically cloth edge) Bass speakers "they" reach deeper, but when extra "noise" is introduced (Drummers or Guitar Players) "theirs" dissappear or lose lots of presence , while "mine" cut through like a knife, always present in the mix.
The thin light easy to break up cone associated with integral paper edge plays a great role there.
I'm not sure I completely understand. So it's the paper edge cones that cut through like a knife?
Apart from the usual Philips drivers, one of my all time favourite large fullrange(ish) drivers is a pair of Isophon Ph 2132 coaxial, where the oval driver is driven full range. Both drivers are paper surround with the tweeter being quite large so it matches the main drivers directionality.
It has a lot of clean crisp bass for its relatively modest size.
Another reference by Mark Fenlon - designer of fullrange speakers - "More significantly, thicker front suspensions limit a can a cone’s ability to resonance at higher frequencies." - source:MarkAudio Alpair Speaker Drivers | H i F i D U I N O
Fair enough! now let's look at this Western Electric 755A surround - YouTube - at 5:50.
Fair enough! now let's look at this Western Electric 755A surround - YouTube - at 5:50.
What was wrong with corrugated paper surrounds?
Referring once again to Briggs, I find some more information which may help answer the question in your title as you have requested. Here it is, slightly edited:
"The cone surround (in addition to the cone material) affects the transient response of the loudspeaker. Soft surrounds improve the transient response by adding dissipation to the edge of the cone with reduced reflection of the flexural wave. It is fairly obvious that, since the cone is expected to respond accurately to the vibrations which are forced upon it by the motor system, any inherent resonances in the cone are undesirable and are bound to upset the transient response.
If you take three identical systems and use (a) normal corrugated surround, (b) cloth surround and (c) foam plastic surround, you will find that switching from a to b and from b to c progressively improves quality. This is due to better transient response and lower bass resonance. (Here Briggs appends three oscillograms of shock tests in each of the cases a, b & c. The number of unwanted vibrations which follow the initial impulse drops from 7 to 6 then 6 to 5 indicating reduced 'ringing' i.e. better transient response."
Referring once again to Briggs, I find some more information which may help answer the question in your title as you have requested. Here it is, slightly edited:
"The cone surround (in addition to the cone material) affects the transient response of the loudspeaker. Soft surrounds improve the transient response by adding dissipation to the edge of the cone with reduced reflection of the flexural wave. It is fairly obvious that, since the cone is expected to respond accurately to the vibrations which are forced upon it by the motor system, any inherent resonances in the cone are undesirable and are bound to upset the transient response.
If you take three identical systems and use (a) normal corrugated surround, (b) cloth surround and (c) foam plastic surround, you will find that switching from a to b and from b to c progressively improves quality. This is due to better transient response and lower bass resonance. (Here Briggs appends three oscillograms of shock tests in each of the cases a, b & c. The number of unwanted vibrations which follow the initial impulse drops from 7 to 6 then 6 to 5 indicating reduced 'ringing' i.e. better transient response."
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It took me a while to figure it out but what he is trying to say is that softer surrounds provide better damping for the resonances in the cone (am I wrong here?)... but then how did the paper surround worked on so many speakers?
He was saying that soft surrounds dissipate the energy i.e. turn it into heat, thus preventing its return to the cone.
Corrugated surrounds obviously work, it's just that other surrounds can work better depending on the application.
Corrugated surround speaker are lively, which is an advantage in guitar speakers as JM Fahey has explained. Such liveliness is not so welcome in hi-fi speakers, although some full-range speakers may put it to good use to brighten up their reproduction.
No speaker driver is perfect, it just depends on what imperfections best suit your purpose!
Corrugated surrounds obviously work, it's just that other surrounds can work better depending on the application.
Corrugated surround speaker are lively, which is an advantage in guitar speakers as JM Fahey has explained. Such liveliness is not so welcome in hi-fi speakers, although some full-range speakers may put it to good use to brighten up their reproduction.
No speaker driver is perfect, it just depends on what imperfections best suit your purpose!
Ok, finally something that makes sense... or is it? because if my soft well measuring surround is absorbing energy how does it not eat more of the energy above the frequency of the first brake up mode? in other words it's going to eat up the highs indiscriminately and some detail hidden in the dynamics (so specific to the nature of sound). I suspect this is true... or they managed to make these surrounds effective just for resonances? I don't think so...
I was asked once to re-cone a friend's Marantz speakers (way back in the Era of Dinosaurs). I got the idea that perhaps the surrounds could be made from some nylon 'rip-stop' cloth, impregnated with thinly diluted liquid chloroprene rubber. So, I bought a yard of the stuff, found a supplier for chloroprene-based cement, another dealer having xylene and tert-butyl di-alcohol, and got to work.
Made a little over what I needed, and the nylon didn't dissolve, tho' I thought it might. Touchy stuff. Cut out rings of the stuff with a suitably modified high-school compass (i.e. Exacto knife instead of pencil lead at tip!), repaired the cracked cones with the same cement, cut out the surrounds, glued on the new ones, worked out a system to get it all into appropriate centered-ness, and let it all dry.
The results were … quite good, but slightly flawed.
After about 3 months the chloroprene seemed to harden past where I thought it'd stop. Thus, my dear surrounds gradually degraded. Still… taking over 100 watts all the time (the friend was a competent drummer, and liked to play to recordings at full volume) beating, 4 or more hours a day, most-every-day of the week, not bad.
Eventually after the Dinosaurs went Extinct, the butyl rubber things were invented, and they seemed much superior.
Still … brings back memories.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
Made a little over what I needed, and the nylon didn't dissolve, tho' I thought it might. Touchy stuff. Cut out rings of the stuff with a suitably modified high-school compass (i.e. Exacto knife instead of pencil lead at tip!), repaired the cracked cones with the same cement, cut out the surrounds, glued on the new ones, worked out a system to get it all into appropriate centered-ness, and let it all dry.
The results were … quite good, but slightly flawed.
After about 3 months the chloroprene seemed to harden past where I thought it'd stop. Thus, my dear surrounds gradually degraded. Still… taking over 100 watts all the time (the friend was a competent drummer, and liked to play to recordings at full volume) beating, 4 or more hours a day, most-every-day of the week, not bad.
Eventually after the Dinosaurs went Extinct, the butyl rubber things were invented, and they seemed much superior.
Still … brings back memories.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
Many older paper cones actually has quite a bit of damping build in.
One of the most extreme examples perhaps being the old Bozak drivers where lamps wool was mixed into the paper pulp.
Another example is the concentric pressed creases some cones has.
In general the trend had been towards more pistonic drivers made with hard, stiff, exotic material paper.
Fostex and Coral are prime examples.
Where Goodman’s, Philips, Richard Allan and Isophone seems to be made from more or less good standard pulp. Which implies more damping and flex.
Hi Krakatoa,
with regard to suspension-less drivers, there was the Fostex SLE series as well, although I have to admit that I never heard any of those. They had a very small gap around the cone, but it appears to me that this is not a problem, if the gap is small enough.
The Fertinacoustics M8 models (which are certainly influenced by the Goodmans Axiom 80) have a gap of about 0,1 mm, and again it appears that, at least in vented boxes, this is no problem. My OB application of the M8 has a slightly larger gap, but less than a mm. Measurements showed a very slight difference compared to a smaller gap - hard to tell if they´re there or just measurement irregularities... but then of course I use my fullrange only above 250Hz.
The Davis Acoustics 20DE8 fullrange has 1mm slits in the cone - again it appears that use in a vented box does not suffer too much.
All the best
Mattes
with regard to suspension-less drivers, there was the Fostex SLE series as well, although I have to admit that I never heard any of those. They had a very small gap around the cone, but it appears to me that this is not a problem, if the gap is small enough.
The Fertinacoustics M8 models (which are certainly influenced by the Goodmans Axiom 80) have a gap of about 0,1 mm, and again it appears that, at least in vented boxes, this is no problem. My OB application of the M8 has a slightly larger gap, but less than a mm. Measurements showed a very slight difference compared to a smaller gap - hard to tell if they´re there or just measurement irregularities... but then of course I use my fullrange only above 250Hz.
The Davis Acoustics 20DE8 fullrange has 1mm slits in the cone - again it appears that use in a vented box does not suffer too much.
All the best
Mattes
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Hello Mattes, I was aware of both your open baffle hanging black flowers (if I remember correctly that's how you call them) and the Fostex surroundless woofers; I did put the question in the context of fullrange speakers, and yes the Fertin speakers are the only ones I know that don't have any surrounds... and they work, it's not like there is just resonances all over the place you can't even listen to them (I don't have the experience of listening to such speakers, but I did listen to speakers with no surrounds lost by decay of by me cutting them out). So I guess in the context of my question this proves a surround does not need to have the properties of an anechoic chamber.
Why do you say Fertin was influenced by Goodmans Axiom 80? I know it's the same surroundless solution but I never heard Fertin borrowing it from Axiom 80. Oh by the way - do you have a description from personal experience what is the sound of surroundless?
On the matter of fullrangers without a surround I know of at least two other models, one of them may not be surroundless (I have a few poor images, can't tell) the other one is an almost unknown "hero" from the past - it's called Exact PX EX (or Exacta, Xacto?) and it's a 30 cm unit from the 70s made in Japan by Takashi Sano with a massive structure attached in the back, high excursion, weird construction, the kind that any collector would like to buy, steel, go to prison for, do things that are hard to describe etc just to own a pair. Anybody that has any information, written or images, on the matter of this unit I am very curious to know more.
The air gap that comes with a surroundless is much less of an issue than people think, I had gaps of 10 mm and it still worked way better than expected in a transmission line.
Why do you say Fertin was influenced by Goodmans Axiom 80? I know it's the same surroundless solution but I never heard Fertin borrowing it from Axiom 80. Oh by the way - do you have a description from personal experience what is the sound of surroundless?
On the matter of fullrangers without a surround I know of at least two other models, one of them may not be surroundless (I have a few poor images, can't tell) the other one is an almost unknown "hero" from the past - it's called Exact PX EX (or Exacta, Xacto?) and it's a 30 cm unit from the 70s made in Japan by Takashi Sano with a massive structure attached in the back, high excursion, weird construction, the kind that any collector would like to buy, steel, go to prison for, do things that are hard to describe etc just to own a pair. Anybody that has any information, written or images, on the matter of this unit I am very curious to know more.
The air gap that comes with a surroundless is much less of an issue than people think, I had gaps of 10 mm and it still worked way better than expected in a transmission line.
To supply some historical information, the Axiom 80 was purposed to operate in a large sealed enclosure or a smaller ARU enclosure (aperiodic loading).
I've not seen one in a vented (reflex) enclosure.
