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Author Topic: Advice on raw loudspeakers (old skool vs new skool)  (Read 38024 times)

Tim Duffin

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whats my grade?
« Reply #70 on: December 31, 2007, 12:30:32 am »

Iain Macdonald wrote on Sun, 30 December 2007 14:53

Tim Duffin wrote on Sun, 30 December 2007 21:16

Well now you are just getting all semantic.  Finite Element Analysis must take place within a computer system-- we agree on that?!  So anyone who uses the method of FEA must have a computer at hand-- it seems like you are arguing about nothing.

Oh, and about the "large" cross sectional horn area--- how large?  You seem to avoid saying anything concrete.  So, you first: I would like to see how you came up with the hypothesis that "stupid" levels cause non linear flow simply due to heat.  If you just made that up, I understand, not many people on the LAB ever back up anything they type with actual math.

T  


Semantics? You obviously used terminology that you didn't understand.

Stupid= Not practically realisable in a conventional/normal design.

Where do I say that it is simply due to heat?

I said "WRT the horn. Remember the pV constant. Also consider that just forcing air through the throat will ultimately, at stupid levels, just give you heat, and non linear airflow problems. ie massive distortion." Have you ever put your finger at the output of a bicycle pump and then compressed the plunger. Did you get a burn from the escaping high pressure air. An old playground trick.

You wanted maths, so here's a little.

1) Boyles law. V

Iain_Macdonald

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Re: whats my grade?
« Reply #71 on: December 31, 2007, 05:56:25 pm »

Tim Duffin wrote on Mon, 31 December 2007 05:30

Iain Macdonald wrote on Sun, 30 December 2007 14:53

Tim Duffin wrote on Sun, 30 December 2007 21:16

Well now you are just getting all semantic.  Finite Element Analysis must take place within a computer system-- we agree on that?!  So anyone who uses the method of FEA must have a computer at hand-- it seems like you are arguing about nothing.

Oh, and about the "large" cross sectional horn area--- how large?  You seem to avoid saying anything concrete.  So, you first: I would like to see how you came up with the hypothesis that "stupid" levels cause non linear flow simply due to heat.  If you just made that up, I understand, not many people on the LAB ever back up anything they type with actual math.

T  


Semantics? You obviously used terminology that you didn't understand.

Stupid= Not practically realisable in a conventional/normal design.

Where do I say that it is simply due to heat?

I said "WRT the horn. Remember the pV constant. Also consider that just forcing air through the throat will ultimately, at stupid levels, just give you heat, and non linear airflow problems. ie massive distortion." Have you ever put your finger at the output of a bicycle pump and then compressed the plunger. Did you get a burn from the escaping high pressure air. An old playground trick.

You wanted maths, so here's a little.

1) Boyles law. V
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Tim Duffin

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Re: whats my grade?
« Reply #72 on: January 01, 2008, 07:27:18 pm »

In all fairness... I did manipulate the numbers a bit by using the ideal gas properties of air.  In reality, there is no way one can have an absolutely perfect vacuum in a pro audio sense because there will be more than 1 sound occuring at the same time.  Most likely, that sound will be over 90db.

So

Using that spl pressure reference 10^5 instead of 10^-12 --- the distance to measurable distortion in free space at 194db is 23 meters.  

I do not have experience designing or modeling horn throats, my experience is limited to acoustic properties of waves in defined spaces.  I will yield to you on this subject.  


Happy New Year!

T

Andy Peters

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Re: whats my grade?
« Reply #73 on: January 01, 2008, 10:46:22 pm »

Tim Duffin wrote on Tue, 01 January 2008 17:27

I do not have experience designing or modeling horn throats, my experience is limited to acoustic properties of waves in defined spaces.  I will yield to you on this subject.  


Praise $DIETY.

-a
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Ian Hunt

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Re: Advice on raw loudspeakers (old skool vs new skool)
« Reply #74 on: January 01, 2008, 11:09:12 pm »

Hi Douglas

RE: Fane drivers, the company closed it's doors last year (possibly the year before) so I would guess that the Colossus is indeed discontinued.

Ian
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Plus ça change, plus c'est la même chose

Iain_Macdonald

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Re: Advice on raw loudspeakers (old skool vs new skool)
« Reply #75 on: January 02, 2008, 04:48:38 am »

Ian,

Fane did close down early last year. But the company, assets, and tooling etc have been bought by the owners of Eminence Europe. They also own PD(Precision Devices). On the web site front page there is a note to say that the Colussus range are in stock, dated 11/26/07. The distribution page indicates that Eminence are the USA distributors.

Best wishes.

Iain.
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Ian Hunt

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Re: Advice on raw loudspeakers (old skool vs new skool)
« Reply #76 on: January 02, 2008, 08:25:45 am »

Oops

It seems I posted prior to verifying my info, thanks Iain and welcome back Fane.
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Plus ça change, plus c'est la même chose
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