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Old 20th October 2012, 09:11 PM   #11
Pano is offline Pano  United States
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Do you know "Tubelab" George down in Miami? He's been at Motorola for years. Used to work up in the Delray plant, I think.
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Old 20th October 2012, 09:39 PM   #12
sreten is offline sreten  United Kingdom
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Hi,

The "theory" of small signal TS parameters bass analysis is well known and
built into many simulation programs, e.g. Basta! goes into the the details :
Basta! technical documentation

Large signal analysis is a completely different kettle of fish and Home is
probably the best resource available to learn about the ins and outs of this.

FWIW designing the bass end of speakers hardly ever involves
the use of anechoic chambers, they are inaccurate in the bass.

rgds, sreten.
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Old 20th October 2012, 10:02 PM   #13
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Quote:
Originally Posted by Frankie Carbone View Post
I want to build some loudspeakers. Some incredible loudspeakers. To do that, I think it is important to understand the physics behind the acoustics and understand them well.
And you need to build some simple, proven designs to get a feel. No book or set of books will teach you everything (and besides there are lots of contradictions -- or better set, a differing viewpoints on which sets of compromises are more important.

As mentioned earlier, T/S are simplistic (for instance, most people still think of them as scalars instead of "curves"). To get a good handle on the physics Berenak's Acoustics (this is n engineering book with all the mtch from 1st principals -- it is not error free). If you could only have 3, Dickason for a basic overview, Harry Olson's Acoustics because everone should have a copy, Leviton, and the AES Loudspeaker Anthologies (some of the best triologies have 6 books in them).

And to fill out a basic library Toole (really should be in the triology above), D'Appolito -- basics of measuring, Colloms, Watkinson.

And i think that no matter which of the 2nd set you get, this book gives a very important alternate viewpoint to the current norm. The Secret of Tube Amplifiers Revealed - and much more!

dave
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Old 20th October 2012, 10:17 PM   #14
sreten is offline sreten  United Kingdom
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Hi,

FWIW great "physics" understanding of speakers is probably more of
a hindrance than help in designing really good speakers. The idea that
you want to design "incredible" speakers presupposes that somehow
you will be better at it than all who have gone before, not very likely.

rgds, sreten.

Most of the physics is very simple, its understanding what physics
is applicable to a speaker design or not that causes problems.
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Last edited by sreten; 20th October 2012 at 10:20 PM.
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Old 20th October 2012, 10:17 PM   #15
AuroraB is offline AuroraB  Norway
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I guess the Olsson and Beranek books are out of print??? Library may be a good idea....''

Martin Collom's "High Performance Loudpeakers" is also worth reading....
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Old 20th October 2012, 10:26 PM   #16
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Quote:
Originally Posted by Pano View Post
Do you know "Tubelab" George down in Miami? He's been at Motorola for years. Used to work up in the Delray plant, I think.
The Boynton Beach facility closed years ago. A lot of those guys came down here to the Ft Lauderdale facility but most of them went into the Mobile Devices section of the facility which is now Google.

Nice deduction on where I work by the way.

I do not know George. At one time there were 9,000 of us between the two plants. Now it's down to about 2,000 or so, especially after the selloff of our mobile phone division to Google.
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Old 20th October 2012, 10:33 PM   #17
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Quote:
Originally Posted by planet10 View Post
And you need to build some simple, proven designs to get a feel. No book or set of books will teach you everything (and besides there are lots of contradictions -- or better set, a differing viewpoints on which sets of compromises are more important.

As mentioned earlier, T/S are simplistic (for instance, most people still think of them as scalars instead of "curves"). To get a good handle on the physics Berenak's Acoustics (this is n engineering book with all the mtch from 1st principals -- it is not error free). If you could only have 3, Dickason for a basic overview, Harry Olson's Acoustics because everone should have a copy, Leviton, and the AES Loudspeaker Anthologies (some of the best triologies have 6 books in them).

And to fill out a basic library Toole (really should be in the triology above), D'Appolito -- basics of measuring, Colloms, Watkinson.

And i think that no matter which of the 2nd set you get, this book gives a very important alternate viewpoint to the current norm. The Secret of Tube Amplifiers Revealed - and much more!

dave
Dave, I can absolutely see the wisdom in this line of thinking. It's the approach that I take when I mentor other engineers on certain subjects. I tell them to go get an older design, study it, study it some more, then start messing with it and see what happens. Then I challenge them to figure out what went wrong and why.

It's called tacit knowledge and it's the kind of knowledge that cannot be transferred by either spoken word or by text. It's that "feel" or intuition that you get from experience, and 8/10 times that gut feel is spot on.

Thinking along these lines, I am considering building a pair of THOR TL speakers designed by Joe D' Appolito as shown here

The Madisound Speaker Store

Do any of you guys know anything about this specific design?

I figure doing this one would give me a bit of that "insight" that you can't learn in a book.

By the way, one of my hobbies is woodworking. I have a woodshop in my garage.

Last edited by Frankie Carbone; 20th October 2012 at 10:36 PM.
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Old 20th October 2012, 10:55 PM   #18
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Quote:
Originally Posted by Frankie Carbone View Post
Thinking along these lines, I am considering building a pair of THOR TL speakers designed by Joe D' Appolito as shown here...
Do any of you guys know anything about this specific design?
It is a good project if you want to know about how things go wrong.

Despite Joe being considered a master speaker design and having literaly written the book on testing, he blew the design of the TL and compounded it by making a stupid measuring mistake.

Clarity on Seas Thor Kit

This is a design i would never personally consider, unless it was part of an article to support the thesis of the above thread,

It breaks 2 guidlines that i hold dear: 1/ it puts an XO right where the ear is most sensitive, and 2/ the centre-to-centre distance of the drivers is greater than 1/4 wavelength at the XO point.

It is also a lot of money to spend on a 1st effort.

I'd suggest getting a pair of these: You can learn a lot.

The Madisound Speaker Store (also available with copper cones)

They may well save you of much of the "conventional" wisdom, and even if not, make a 1st class midrange.

dave
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Old 20th October 2012, 10:58 PM   #19
Loren42 is offline Loren42  United States
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Quote:
Originally Posted by Frankie Carbone View Post
Dave, I can absolutely see the wisdom in this line of thinking. It's the approach that I take when I mentor other engineers on certain subjects. I tell them to go get an older design, study it, study it some more, then start messing with it and see what happens. Then I challenge them to figure out what went wrong and why.

It's called tacit knowledge and it's the kind of knowledge that cannot be transferred by either spoken word or by text. It's that "feel" or intuition that you get from experience, and 8/10 times that gut feel is spot on.

Thinking along these lines, I am considering building a pair of THOR TL speakers designed by Joe D' Appolito as shown here

The Madisound Speaker Store

Do any of you guys know anything about this specific design?

I figure doing this one would give me a bit of that "insight" that you can't learn in a book.

By the way, one of my hobbies is woodworking. I have a woodshop in my garage.
That is a good choice.

Someone I know used those as a core for a larger system. The Thor design is in the middle of the cabinet. The lower two drivers are part of a larger transmission line that runs either side of the inner cabinet.

Dr. Mark Carter has the pictures of the build somewhere on his site on the link below. Contact him is you would like at Dr. Mark Says.

THE FINISHED WALBERSWICK STUDIOS - mdcarter's Photos
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Old 20th October 2012, 11:02 PM   #20
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Originally Posted by Loren42 View Post
Someone I know used those as a core for a larger system. The Thor design is in the middle of the cabinet. The lower two drivers are part of a larger transmission line that runs either side of the inner cabinet.
Looks more like a start from scratch using the same basic set of drivers.

dave
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