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Author Topic: New LABS being born  (Read 13662 times)

Marjan Milosevic

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Re: New LABS being born
« Reply #20 on: June 20, 2013, 03:48:12 pm »

I still dont understand WHY you did that.
First of all you are altering a design made by one of the most brilliant minds in the audio industry (do you really think you can improve it?), second, it is obvious that you dont really understand the theory behind how this box works.
So WHY????

Kristopher Cox

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Re: New LABS being born
« Reply #21 on: June 20, 2013, 04:40:20 pm »

I still dont understand WHY you did that.
First of all you are altering a design made by one of the most brilliant minds in the audio industry (do you really think you can improve it?), second, it is obvious that you dont really understand the theory behind how this box works.
So WHY????

I give up - nevermind
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Tim McCulloch

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Re: New LABS being born
« Reply #22 on: June 20, 2013, 09:33:59 pm »

I give up - nevermind
j

Model your changes in Professor McBean's HornResp tool.  Model Tom's original design.  Compare and contrast.

Marjan is being critical because, as a designer himself, he sees your proposal as being speculative and not supported by known horn/transducer behavior.

Before taking your toys and moving on, consider showing how you can support your modifications with a mathematical model.  If it works I'm sure Marjan and others will be quick to acknowledge your improvement.
« Last Edit: June 20, 2013, 09:36:08 pm by Tim McCulloch »
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Jeff Robinson

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Re: New LABS being born
« Reply #23 on: June 21, 2013, 09:45:07 am »

Fixed the flares - machined 2 sides - fit like a glove. ??? I have some concern with the rear chamber volume.  I have looked through some of the archived posts and it seems that there was a version put forth that moved the walls closer together to get a shallower throat and give up some area to the sealed speaker baffle.  This however did move the compression ratio up to 3.  I have an idea for a similar change but not as drastic.  What if I took an 8" diameter PVC pipe - 4" long and inserted it into the upper part of the flare panel.  This would gain me about 200 square inches for the speaker baffle and extend the throat later into the flare aperture w/ a sharper mouth opening which is what the revision was all about.  Any suggestions?

Hi Kris

The LAB12's have a very loose suspension (Qms >>9) and this is where the very tight rear chambers give the system it's gain (plus air pressure is more linear than the spider's spring tension: = lower distortion). Look for Tom Danley's posts in the early archives to find his mentioning this (I think it was the post when he discussed the changes he made after getting the first prototype sample of the LAB12 from Jerry McNutt with Eminence). Enlarging the rear chambers will do multiple things: reduce the gain and increase bandwidth (subject to other low/high pass limiting T/S math involving throat area and volume, etc) as well as allowing greater excursion.

Tom also said (in an email to me, that in the target bandwidth of the labhorn) smooth expansion is not all that important (of course it is very important as you go up into shorter wavelengths at higher frequencies where disturbances approach lambda).

Jeff Robinson
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Bird thou never wert
That from Heaven, or near it
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Gregory Fenn

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Re: New LABS being born
« Reply #24 on: July 20, 2013, 12:35:12 pm »

I give up - nevermind

Don't quit; regroup, reconsider, study and approach the problem from a different angle. Sometimes you learn a lot from trial and error, but if you know that something is going to fail don't. Perhaps you may come up with something different and new.
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Ivan Beaver

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Re: New LABS being born
« Reply #25 on: July 20, 2013, 12:47:47 pm »

. Perhaps you may come up with something different and new.
But in something that is based on physics/science-it is not a matter of "trial and error". but rather trail based on scientific principals.

Sometimes there are the "un accounted fors" and such that can reach out an bite you- but when it is based on pure guesswork based on no principals-then it will be A LOT OF trial and error.

You have to look at all the different angles/problems-not focus on a single idea.  If you choose to just "ignore" the rest of what is happening-then sure-it can "appear" to work in that one aspect.

Of course that doesn't stop a lot of our industry who want to break down very complicated processes into simple drawings that anybody can understand.  "LOOK-it's a cylindrical wavefront----------------"  YEAH RIGHT
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Kristopher Cox

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Re: New LABS being born
« Reply #26 on: July 22, 2013, 07:14:56 pm »

Starting to take shape - few little details to correct but it is going together like a jigsaw puzzle so far
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Kristopher Cox

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Re: New LABS being born
« Reply #27 on: July 22, 2013, 07:19:51 pm »

 :)
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Kristopher Cox

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Re: New LABS being born
« Reply #28 on: July 22, 2013, 07:21:24 pm »

 :)
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Marjan Milosevic

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Re: New LABS being born
« Reply #29 on: July 24, 2013, 07:12:41 am »

Fantastic wood work there.

ProSoundWeb Community

Re: New LABS being born
« Reply #29 on: July 24, 2013, 07:12:41 am »


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