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Multi-Way Conventional loudspeakers with crossovers

Surround less, spider less, mid bass driver
Surround less, spider less, mid bass driver
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Old 4th July 2014, 02:19 PM   #21
Overkill Audio is offline Overkill Audio  United Kingdom
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Default Patent & Trade mark protection

Just a point of caution....
The best protected trade mark in the world will give you zero protection over your invention or Intellectual property.
All a trade mark will do is give you title to a name / logo / image....
Trade mark protection will not protect the concept, technology, or variations there of.

You can write your own patent application for $100 (average European fee for patent submission on line) and then take it to a good patent lawyer and get an hour free consultation ( most do offer this) and an estimate for the professional patent lawyer to modify and strengthen your application.

My advice is to focus on protecting your IP....Without that you will simply hand the fruits of your labour to the commercial designers who stalk sites like this 24 / 7....
Hope this helps and all the best
Derek.
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Old 4th July 2014, 02:47 PM   #22
Jef Nuyts is offline Jef Nuyts  Belgium
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Quote:
Originally Posted by sreten View Post
Hi,

Us old farts know nothing, go with the clueless enthusiasts.

The outer aluminium ring is very poor cone termination,
it will work for bass, but won't work for good midrange.

Its telling the driver is always shown horizontal, its
obvious it won't work well vertical, as it has to.

Ferrofluid has been tried in bass units and it doesn't work,
and that is fitted with standard surrounds and spiders.

Any driver needing a separate supply needs to be great
to succeed, with no issues, I really can't see that here.

FWIW the issues of interaction of magnetic and suspension
linearity have been well covered previously, so here all you
are getting is a claim of an offering of something ideal.

Something us old farts have seen a lot of in our time,
different, unless really good, hardly ever means better.

rgds, sreten.

Not that I'm that old, but I might as well be.
1) I thought about cone termination that's why I try first with surround and then without to hear the difference. rocking modes or not the sound is much better and defined without, and yes also on high volumes. If the cone is light and stiff with good damping over the whole surface (thin rubber layer) the rocking modes or not that much. I think also because of the very stif outerdiameter of the cone with the alu ring (thin but high)
=> there are artikels to depend on and there are real world testing results... you must consider both to judge.

2) The driver works vertical no problem. I love to discuss some aspects thats the whole reason that i place this threat but the "clueless enthusiasts like you say" do believe me. Lying is not the purpose... and has also no contribution for me and others.

3) Why ferro don't work? Works like a charm. High BL value, high viscosity ferro applied only on the inside of the former (perfectly smooth) the outside is not good because of the ripples from the coil. You have also to be sure there is no pressure change in the magnetic structure => the ferro will stay in the gap. I have also a video were you can see how the speaker is driven to it's limits.

4) the issues of interaction of magnetic and suspension
linearity have been well covered previously => Do you have andy prove or example? Yes maybe there is but at the expense of other problems.

you can see the suspension compensation in the picture.
green line => suspension force. yellow line => voicecoil force.
X-I curve is full lineair till +/-4mm.
I want to see if someone can make this with a spider? No, impossible.

Regards,
Attached Images
File Type: png EM suspension.PNG (49.9 KB, 619 views)
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Old 4th July 2014, 03:54 PM   #23
Jef Nuyts is offline Jef Nuyts  Belgium
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Oke there is alot concern about cone termination. And I understand the concern.
In my opinion if you consider to eliminate the surround it is important in order to get as close as possible to move pistonic. In theory, if you can move pistonic there is no need for termination. In practice it is not possible i know, but a very light strong cone even on the outside (alu ring) and with damping material on it will do the job.
I did test the cone without any crossover and there is no audible ringing.
Why is it that foam surrounds sounds better than rubber? Rubber tends to be better damping? Foam is lighter...
In the beginning the intention is not to make a surroundless speaker but with this design it is possible so i tried it. The invention is not surroundless, it is the changable suspension and full lineair but it sounds better without surround thats all i can say.

Take Care,
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Old 4th July 2014, 04:18 PM   #24
afa is offline afa  Australia
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Quote:
"I vaguely remember, years ago, there's a Japanese big company providing products of surround-less woofer(s) on their high end boombox (or the likes). It's working like a sliding piston in a cylinder. And it was even promoted by its ability of long stroke. (small diameter, that is)"
..I've got one, it is/was made by Panasonic its got two spiders and the surround is a bunch of bristles attached to the edge of the cone that form a sort of air tight seal that rubs on the inside edge of the basket....its crap.. the driver just chuffs away making lots of spurious noises...
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Old 4th July 2014, 04:43 PM   #25
5th element is offline 5th element  United Kingdom
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I don't suppose we can get some FR and distortion measurements of this thing? It looks interesting.
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Old 4th July 2014, 05:29 PM   #26
Jef Nuyts is offline Jef Nuyts  Belgium
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Quote:
Originally Posted by thoriated View Post
Why not simply make it as a kind of a voice coil at the cone perimeter, as well as elsewhere if desired? Then you can tune suspension damping if desired with a version of the actual signal to be reproduced.
Hi,

Good thinking, also thought about this but there are some problems i guess:

- More damping with low Q driver resulting in overdamping. So low end output is very restricted.

- More amp power is needed.

- the slightest difference of signal between the two coils wil give some irregularity and distorted sound.

- also there is no zero (rest)point if there is no signal. don't see a solution te put the cone perfect in the middle. Or, after you play music for a while the cone position can shift it's rest position.


But thanks for the suggestion!

Rgrds,
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Old 4th July 2014, 07:44 PM   #27
Jef Nuyts is offline Jef Nuyts  Belgium
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Quote:
Originally Posted by 5th element View Post
I don't suppose we can get some FR and distortion measurements of this thing? It looks interesting.
Yes you will, but for the moment I only have these data when it is placed in a closed cabinet and with surround and papercone setup. But the paper cone was rubbish too thin. I just decided to make two whole new drivers like the last one. no surround and spider and kevlar dome but this will might take a while. The driver I talk about here (the one i tested last weekend) is dead so I can't do the measurement of it. The reason it is broken is my own fault. On the back there are 4 bolts to hold the bottomplate to the sidewall. I wan't to change the basket for testing but this is also bolt to these four bolts. When loosing them the polepiece just came out of center against the outer ring of the airgap. Almost impossible to disassemble without any damage.

distortion and FR but in a full setup (2way with seas tweeter) so this don't tell much. Also with the thin paper dome.
The dark brown line is the plot of my Keff-Q75 for reference. Oke this is not a top notch speaker but also not a bad one.


distortionDomepaperSurr.JPG

FRDomepaperSurr.JPG

distortionKeffQ75.JPG

Rgrds,

Last edited by Jef Nuyts; 4th July 2014 at 08:05 PM.
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Old 4th July 2014, 08:18 PM   #28
Jef Nuyts is offline Jef Nuyts  Belgium
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Maybe interesting if someone likes radial speakers.

The plot is from the same dome speaker but placed horizontal under 5 degree and offcourse with the same tweeter just above the driver.
The sound is less direct but more present in the whole room and a much bigger soundfield. Also pleasant to listen to.

distortionDomepaperSurrRADIAL.JPG

Last edited by Jef Nuyts; 4th July 2014 at 08:34 PM.
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Old 4th July 2014, 08:51 PM   #29
Andrew Eckhardt is offline Andrew Eckhardt  United States
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>Why is it that foam surrounds sounds better than rubber?

I dunno. Added mass to damping ratio? You could always place a foam surround on the cone and shave off everything but the inner quarter of the roll. It wouldn't be everything a normal setup would be but add a little lossy strength to the edge.

Last edited by Andrew Eckhardt; 4th July 2014 at 08:54 PM.
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Old 4th July 2014, 09:03 PM   #30
Jef Nuyts is offline Jef Nuyts  Belgium
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Quote:
Originally Posted by afa View Post
"I vaguely remember, years ago, there's a Japanese big company providing products of surround-less woofer(s) on their high end boombox (or the likes). It's working like a sliding piston in a cylinder. And it was even promoted by its ability of long stroke. (small diameter, that is)" ..I've got one, it is/was made by Panasonic its got two spiders and the surround is a bunch of bristles attached to the edge of the cone that form a sort of air tight seal that rubs on the inside edge of the basket....its crap.. the driver just chuffs away making lots of spurious noises...
Yes oké like you say it and they made it, it must be bad and I think cheap. (unbelievable that companies like panasonic make such thoughtless rubbish junk) The outergap clearance must be 1mm or something...

Does someone know Fertin speakers?

Products

Also surroundless and these are good but expensive speakers 2000Euro each I red somewhere. France company.
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