Anyone have recommendations on books for loudspeaker driver tech?
Olson and Beranek are classic but a bit old (haven't read the updated Beranek yet)
Geddes doesn't cover my area of interest, optimisation of voice coil, pole pieces, B/H circuit etc.
John Eargle's book is the closest to what I want but seems to have some errors and lacks depth.
IIRC there was a text in Deutsch but I don't remember the title..?
Hopefully
David
Olson and Beranek are classic but a bit old (haven't read the updated Beranek yet)
Geddes doesn't cover my area of interest, optimisation of voice coil, pole pieces, B/H circuit etc.
John Eargle's book is the closest to what I want but seems to have some errors and lacks depth.
IIRC there was a text in Deutsch but I don't remember the title..?
Hopefully
David
High Performance Loudspeakers - Colloms
is probably closest to what you want but its not very detailed.
Not a lot of maths for real life design either.
I don't think there's anything that covers the subject like Self & Cordell for amps.
is probably closest to what you want but its not very detailed.
Not a lot of maths for real life design either.
I don't think there's anything that covers the subject like Self & Cordell for amps.
I usually keep my eye open for something like this but haven't seen anything beyond those mentioned (have them all; the 50's stuff is probably the best from that list).
You might have better luck with the AES Loudspeaker Anthologies
AES Anthologies and Monographs
I have 3 and 4 and they're not really what you're looking for. You may have better luck with 1 and 2
You might have better luck with the AES Loudspeaker Anthologies
AES Anthologies and Monographs
I have 3 and 4 and they're not really what you're looking for. You may have better luck with 1 and 2
Olson and Beranek are still highly relevant. Dickason's Loudspeaker Cook Book is OK for a practical approach, although I haven't seen the later editions.
That's pretty much what I want.
Yes, as Aurora also noted, these are still relevant, I just wish there was a better choice.
Last few days has been spent with back issues of the JAES and some of the articles are the best information so far.
Unfortunately I don't have access to convention papers.
Builds character to have to work it out for myself I suppose.😉
Thanks all for the comments, seems I haven't overlooked too much.
Best wishes
David
Lookkahere:
[1] G. P. Geaves, J. P. Moore, D. J. Henwood and P. A. Fryer, Verification of an approach for Transient Structural Simulation of Loudspeakers incorporating Damping, Presented at the 110th Convention 2001 May 12–15 J Amsterdam, The Netherlands.
[2] Christopher. J. Struck, Investigation of Nonrigid Behaviour of a Loudspeaker Diaphragm Using Modal Analysis, Journal of Audio Engineering Society, Vol. 38, No. 9, 1990 September, pages 667-674.
[3] F. J. M. FRANKFORT, Vibration Patterns and Radiation Behaviour of Loudspeaker Cones, Journal of the Audio Engineering Society, 1978 September.
[4] Shinichi Sakai, Yukio Kagawa, Tatsuo Yamabuchi, Acoustic Field in an Enclosure and its Effect on Sound-Pressure Responses of a Loudspeaker, Journal of Audio Engineering Society, Vol. 32, No. 4, 1984 April, pages 218-227.
[5] Arie J.M. Kaizer and Ad Leeuwestein, Calculation of the Sound Radiation of a Nonrigid Loudspeaker Diaphragm Using the Finite-Element Method, Journal of Audio Engineering Society, Vol. 36, No. 7/8,1988 July/August, pages 539-551.
[6] S.-W. Wu, S.-H. Lian and L.-H. Hsu, A Finite Element Model for Acoustic Radiation, Journal of Sound & Vibration (1998) 215(3), pages 489-498, Article No.sv981664.
[7] R.J. Astley, Wave envelope and infinite element schemes for acoustical radiation, International Journal for Numerical Method in Fluids, Vol. 3, 1983, pages 507-526.
[8] R.J. Astley, W. Eversman, Finite Element Formulations for Acoustical Radiation, Journal of Sound and Vibration, Vol. 88, 1983, pages 47-64.
[9] Harry A. Schenck, Improved Integral Formulation for Acoustics Radiation Problems, The Journal of the Acoustical Society of America, Vol. 44, No. 1, 1968, pages 41-58.
[10] Ciskowski R.D., Brebbia C.A. Boundary Element Method in Acoustics Computational Mechanics Publications Southampton Boston Co-published with Elsevier Applied Science London New York 1991 reprint 1995.
[11] CROCKER M.J. Handbook of Acoustics John Wiley & Sons Inc.
[12] ANSYS (on-line) Manuals
[13] The Finite Element Method for Engineers
[14] Young W. Kwon, Hyochoong Bang, The Finite Element Method using MATLAB, CRC Press, ISBN 0-8493-9653-0
[15] Concepts and Application of Finite Element Analysis
[16] O. C. Zienkiewicz, The Finite Element Method in Engineering Science (McGraw-Hill, London, 1971)
[17] G. P. Geaves, Design and Validation of a System for Selecting Optimised Midrange Loudspeaker Diaphragm Profiles, Journal of Audio Engineering Society, Vol. 44, No. 3, 1996 March, pages 107-117.
[1] G. P. Geaves, J. P. Moore, D. J. Henwood and P. A. Fryer, Verification of an approach for Transient Structural Simulation of Loudspeakers incorporating Damping, Presented at the 110th Convention 2001 May 12–15 J Amsterdam, The Netherlands.
[2] Christopher. J. Struck, Investigation of Nonrigid Behaviour of a Loudspeaker Diaphragm Using Modal Analysis, Journal of Audio Engineering Society, Vol. 38, No. 9, 1990 September, pages 667-674.
[3] F. J. M. FRANKFORT, Vibration Patterns and Radiation Behaviour of Loudspeaker Cones, Journal of the Audio Engineering Society, 1978 September.
[4] Shinichi Sakai, Yukio Kagawa, Tatsuo Yamabuchi, Acoustic Field in an Enclosure and its Effect on Sound-Pressure Responses of a Loudspeaker, Journal of Audio Engineering Society, Vol. 32, No. 4, 1984 April, pages 218-227.
[5] Arie J.M. Kaizer and Ad Leeuwestein, Calculation of the Sound Radiation of a Nonrigid Loudspeaker Diaphragm Using the Finite-Element Method, Journal of Audio Engineering Society, Vol. 36, No. 7/8,1988 July/August, pages 539-551.
[6] S.-W. Wu, S.-H. Lian and L.-H. Hsu, A Finite Element Model for Acoustic Radiation, Journal of Sound & Vibration (1998) 215(3), pages 489-498, Article No.sv981664.
[7] R.J. Astley, Wave envelope and infinite element schemes for acoustical radiation, International Journal for Numerical Method in Fluids, Vol. 3, 1983, pages 507-526.
[8] R.J. Astley, W. Eversman, Finite Element Formulations for Acoustical Radiation, Journal of Sound and Vibration, Vol. 88, 1983, pages 47-64.
[9] Harry A. Schenck, Improved Integral Formulation for Acoustics Radiation Problems, The Journal of the Acoustical Society of America, Vol. 44, No. 1, 1968, pages 41-58.
[10] Ciskowski R.D., Brebbia C.A. Boundary Element Method in Acoustics Computational Mechanics Publications Southampton Boston Co-published with Elsevier Applied Science London New York 1991 reprint 1995.
[11] CROCKER M.J. Handbook of Acoustics John Wiley & Sons Inc.
[12] ANSYS (on-line) Manuals
[13] The Finite Element Method for Engineers
[14] Young W. Kwon, Hyochoong Bang, The Finite Element Method using MATLAB, CRC Press, ISBN 0-8493-9653-0
[15] Concepts and Application of Finite Element Analysis
[16] O. C. Zienkiewicz, The Finite Element Method in Engineering Science (McGraw-Hill, London, 1971)
[17] G. P. Geaves, Design and Validation of a System for Selecting Optimised Midrange Loudspeaker Diaphragm Profiles, Journal of Audio Engineering Society, Vol. 44, No. 3, 1996 March, pages 107-117.
Well this list certainly brings back memories 🙂
Alas, I don't think ANY of them will help Dave design motor systems which I think is what he wants.
For magnet design, there used to be a TDK application note. It's focussed on Ferrite design but it explains important stuff clearly & simply including the assumptions & gotchas which also apply to Alnico & NdFeB (provided you can get good info in datasheets 😀)
I believe, this Millenium, there are a couple of free magnet FEA programmes that are good but you still need to know the gotchas.
For the coil, Garner & Jackson describe a Fortran programme which I later updated. The application to Dave's requirements is that it automates what us horny handed speaker unit designers do.
I had a DOS programme that combined the two for Ferrite motor design including a very good iterative estimate of saturation for the common type of motor systems we used.
Alas, I lost both it and the source code this Millenium in a HD crash. 😡
Considering that there has been no real improvement in the understanding of drivers since the 30s as evidenced by the fact that the best drivers a
maybe from that era, I can't see why the classics are not the most worthy. Imo old drivers and horns coupled with modern dsp is the state of the art.
maybe from that era, I can't see why the classics are not the most worthy. Imo old drivers and horns coupled with modern dsp is the state of the art.
I think https://www.klippel.de/know-how/application-notes.html will show quite a bit more is known in recent decades about motor design, suspensions, diaphragms...
basic principles may be the same but the ability to design closer to optimums, and build to the design are greatly improved
multiphysics packages like Comsol cost less than mid market new cars - I'm pretty sure my little brother has often had near $100k of "toys" between trucks, off road vehicles and boats on his Ford Machinist' salary
basic principles may be the same but the ability to design closer to optimums, and build to the design are greatly improved
multiphysics packages like Comsol cost less than mid market new cars - I'm pretty sure my little brother has often had near $100k of "toys" between trucks, off road vehicles and boats on his Ford Machinist' salary
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Oh there's hell of a lot more that's known about drivers today but no simple explanation anywhere of even basic and important stuff like how to design a motor .. or why Rice & Kellog's invention is one of only 2 transduction mechanisms that have flat frequency response.
Knowing this helps us to understand the pros & cons of various design details.
You really need to work for a large speaker design & maker company.
The only good new understanding readily available (cos some good & some bad software) is from Aboriginal Elders Thiele & Small .. But that's all aimed at those who just want to stuff units into boxes.
The Garner & Jackson paper is one of the very few which helps those who design units from scratch.
Olson & Beranek are mandatory for anyone designing speakers but I challenge you to find anything in them that helps you design a unit today.
jcx, thanks for the Klippel links. All good stuff. His gear simplifies loadsa stuff which used to take ages to do. Wish I had his gear when I was in the trade last Millenium.
Dave, I take it you've copied & tried to digest from JAES Thiele's original paper, Small's 3 parter and also Don Keele's stuff. Not quite "how to design a drive unit" but useful & important stuff.
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FEMM seems to be the consensus choice.
Kind of LTSpice for magnetics.
Replacement of your lost DOS code would be a fine educational exercise.
I looked at a COMSOL model of a compression driver with boundary layer viscosity, heat flow, nonlinear air compression, the works.
Very impressive, I hope for freeware to match FEMM.
I am less optimistic about a cheap Klippel analyser😉
At least their free application notes are helpful but I'd already seen them.
Thanks for the link anyway.
Best wishes
David
Yes, probably should reread them, learn extra when I read with a different perspective.
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hello Dave,
Obviously I overlooked your request foot loudspeaker motor info, instead of diaphragm info.
Dick Pierce wrote an article in the early years of Speakerbuilder Magazine around 1980 or 1981 describing very basic VC calculations a plus a speadsheet he used at Precision Loudspeakers at the time to determine Q factor for various magnet-vc combinations, including lenght of wire, if memory serves me well.
It is all very, very basic stuff, but for starters it gives good insight to basic factors involved in motor design.
This may have been mentioned before, but I also recall Vance Dickason in one of the LS Recipe books had a chapter about optimization of motor design for a (Dayton?) woofer, using some FEM optimization software.
Good luck with your journey: I will follow it with keen interest.
Eelco
Obviously I overlooked your request foot loudspeaker motor info, instead of diaphragm info.
Dick Pierce wrote an article in the early years of Speakerbuilder Magazine around 1980 or 1981 describing very basic VC calculations a plus a speadsheet he used at Precision Loudspeakers at the time to determine Q factor for various magnet-vc combinations, including lenght of wire, if memory serves me well.
It is all very, very basic stuff, but for starters it gives good insight to basic factors involved in motor design.
This may have been mentioned before, but I also recall Vance Dickason in one of the LS Recipe books had a chapter about optimization of motor design for a (Dayton?) woofer, using some FEM optimization software.
Good luck with your journey: I will follow it with keen interest.
Eelco
Thank you for the references and kind words.
I am interested in cone behaviour too but even with finite element models there seems to be a lot of trial and error.
The instrumentation to study cone break up is not cheap or readily available so I think there is little chance I will try that.
I would use a commercially available cone that someone else has spend the development effort and money on.
In the meantime I wish to understand the speakers sufficiently well that I could build one, I find this makes me realize all the details I never considered.
Then the project moves into the queue😉
I have another thread about this http://www.diyaudio.com/forums/multi-way/282899-efficient-direct-radiator-woofer-optimization.html that I started after the initial lack of response to this thread.
Best wishes
David
If some of this can be put on the web, it would be very useful.
Don't think its written down anywhere else .. even the basic stuff.
Yes. SOTA in FEA for cones in the 90's was Julian Wright, Celestion and Patrick Macy, PAFEC. I provided most of the test cases & validation.
Patrick's 'breakthrough' was developing a usable acoustic Boundary Element Model. Before this, with FEA, you had to mesh all the air in your 'room'.
In dem days, it was setting up the problem and starting it at the end of the day ... only to find the next morning that it had crashed. 😡
Verification was originally with Laser Holography Fryer (which actually predates the BEM work) and later with a Scanned Laser Doppler Interferometer Wright also at Wharfedale.
If it seems the same people are involved in all this, its cos UK speaker R&D is very incestuous 😱
_____________________
To help those who aren't going to buy a Scanning Laser Doppler Interferometer and $$$ FEA package, the pearls of wisdom from this long & drawn out work can be summed up as follows ...
- avoid straight sided cones
- you gotta match the surround shape/material/attachment to the cone
- ditto with the coil
- don't discount Unique Fibrous Material (paper) My main search for cone materials was to find an Engineered Plastic that replicated its properties. 🙂
There's Harwood's 3 parter in Wireless World describing the original Bextrene BBC monitor.
______________________
Another old book worth keeping an eye out for is 'Loudspeakers' - Ted Jordan (ex Celestion / Jordan Watts / A&D) 1970's (?) Maths is wonky but he explains some very important concepts clearly.
@kgrlee:
This might well be your dream cone and dome material: biocellulose. Difficult to produce though. I think Sony used it in its headphones year ago.
Dome speaker, Matusiak G. et all; Rights: Institute of Biopolymers and Chemical Fibres, Tonsil S.A. Września. Protected by patent number: 204309. Polish Republic Patent Office, BUP 08-04-2002, no. 08/2002. The shell vibration and sound radiation were studied. Diaphragm speaker of bacterial cellulose the so-called bio-cellulose, as well as a complete speaker composed of the membranes were designed and patented.
This might well be your dream cone and dome material: biocellulose. Difficult to produce though. I think Sony used it in its headphones year ago.
Dome speaker, Matusiak G. et all; Rights: Institute of Biopolymers and Chemical Fibres, Tonsil S.A. Września. Protected by patent number: 204309. Polish Republic Patent Office, BUP 08-04-2002, no. 08/2002. The shell vibration and sound radiation were studied. Diaphragm speaker of bacterial cellulose the so-called bio-cellulose, as well as a complete speaker composed of the membranes were designed and patented.
Sony used to claim their Unique Fibrous Material (UFM) cones were made with pure spring water from Mt. Fuji.
Our UFM used pure Yorkshire Water from Esholt Sewage Works. 🙂
BTW, the breakup behaviour of a good sounding UFM cone is very different from that of a good sounding plastic cone as seen on a SCAnned Laser Plot.
Kevlar & other woven composite cone materials are good for subs but their assymetrical breakup prevents them from having the very best midrange performance.
The tech seems to have moved on once more.
Now laser position sensor coupled to ADConverter and velocity is derived.
At least that's what Klippel does and they seem to own the market for off-the-self systems AFAIK.
The JBL 2226 uses a simple cone and it seems to work well.
Apparently because they haven't tried to extend the upper frequency response.
The asymmetry of simple woven composites always bothered me, not surprised to find my expectation confirmed.
A properly made composite could be radially braided or woven, or even have unidirectional fibre bundles laid down, as they do in composite sails now.
Dammit, now you made me want to try cone fabrication too😉
Back to the JAES.
Best wishes
David
A nice match for a composite cone would be a hyperboloid of revolution of one sheet (well, half of one, to be pedantic)
Now I really want to do this, just to use such neat maths.
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I don't think anyone does this even today.
B&W used to be the biggest serious user of woven composite cones and they just squashed Triaxial weaves into shape.
But as always, you need to ask, "what do we get for the complexity?"
There's a myth that very rigid cones are 'better'. This was squashed by Frankort as early as 1978 and Kaizer (even earlier) .. both from Philips IIRC.
Of course I'm generalising and one of the big advantages of UFM is its very high stiffness to weight ratio with good damping. The only real disadvantage is inconsistency in production. There have been UFM systems among those with the lowest audible midrange colouration.
But very stiff cones are appropriate for subs.
Ted Jordan was into hyperboloids.
The PAFEC & SCAnned Laser Plot work we did show little or no advantage from slightly curved cones. Matching to the surround probably more important.
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Too much to expect that the idea had not occurred to anyone else.
A quick search shows the only company to currently use the idea is Australian, from Ballina of all places. I didn't know of them until now.
The idea occurs to use a sandwich cone with the front face as one half of the matched hyperboloid of two sheets. (the Wikipedia article has some visuals that make it obvious how they would fit.)
Not sure if there's any special benefit, maybe it's like those complementary symmetry power amplifier inputs that just look like an inevitable combination.
Haven't hit the JAES yet.
Best wishes
David