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Old 11th March 2011, 03:03 AM   #591
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Quote:
It also cuts of the path length a little (see blue line) although this is to small to be significant.
The Blue line looks longer to me. seems like the more ref lines you put into a corner the more accurate the measurements can be. I only used one becuase I was hand drawing. Looking at the three you put in the last post seems the best way to measure. Andy
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Old 11th March 2011, 03:18 AM   #592
Djim is offline Djim  Netherlands
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The other two important reference points I show you in green (90 degrees straight on the outline of the cab). If you integrate these 3 new reference points you will see in your horizontal representation why this is important. Maybe not in volume difference but sure when it comes to air resistance, I think.

In my opinion this is exactly the reason why corner correctors (deflectors whatever...) are so 'sensitive' to the real output plot. I think JBell 'discovered' that the hard way with his big cab and his cube.
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Old 11th March 2011, 03:21 AM   #593
jbell is offline jbell  United States
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djim:

I like the way you think.... and some how, I think I owe you...

yes, my learning was definitely, 'the hard way....'
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Old 11th March 2011, 03:26 AM   #594
Djim is offline Djim  Netherlands
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Now I will show the difference what it makes for corner bracings.
On the left the method how it is done by the 4 reference points method.
On the right how it is done by the 7 reference points method by 2 pieces instead of one.
In 'huge' corners (like in the big cab) I suggest 3 pieces...

The importance of those 'new' 3 reference points is this: The all point the the max (corner) and minimum path width that are not 'visible' with the method that is used around here...
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Old 11th March 2011, 03:31 AM   #595
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by jbell View Post
djim:

I like the way you think.... and some how, I think I owe you...

yes, my learning was definitely, 'the hard way....'
Not at all JBell... and thanks for my broken lips after the cold carnaval event over here "stupid" flutes...

(Oh and another more important thing I still on that challenge, improving that 'silly' concept of yours!)

Last edited by Djim; 11th March 2011 at 03:33 AM.
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Old 11th March 2011, 04:13 AM   #596
Djim is offline Djim  Netherlands
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Now with the 'new' reference points in mind, I try again (remember this is rough drawing idea)...
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Last edited by Djim; 11th March 2011 at 04:15 AM.
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Old 11th March 2011, 05:09 AM   #597
Djim is offline Djim  Netherlands
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And my second suggestion (before I fall in sleep). If you worry about point A, it almost follows the outline of the driver's cone. You can see it as a driver volume correction (in both ways). Tell me what you think...

Btw it was my intention to lift the driver panel parallel from its original position... sorry for my skills
The extra volume around corner one is now partly 'used' by the driver panel.
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Last edited by Djim; 11th March 2011 at 05:14 AM.
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Old 11th March 2011, 09:03 AM   #598
AndrewT is offline AndrewT  Scotland
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I am lost in the need for this "area" accuracy around the bends.
Previously I have seen the experts and good amateurs telling us that for low freqency reproduction that step changes in area make no difference to the sound that comes out.
I remember one designer saying that an LF horn would work just as well with cascaded parallel sections of increasing area.
They further went on to say that filling in the corners with rounded profile was a waste of effort and material.

DJM in his graphical method of minimising the "area" change is slowly approaching a curved "bend".

Is this really going to affect a speaker that has a maximum upper passband frequency of 60 to 120Hz?
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Old 11th March 2011, 01:58 PM   #599
tb46 is offline tb46  United States
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Hi AndrewT,

Post #598: "Is this really going to affect a speaker that has a maximum upper passband frequency of 60 to 120Hz."

I doubt it, but both screamerusa and jbell have seen measurable differences in their respective tapped horns by using reflectors. So far nobody has reported controlled and repeatable measurements of the effects of reflectors in a tapped horn. So beyond screamerusa's and jbell's reports, we are just guessing.

I think they are most useful for freeing up space for wheels, handholds, and spots to the protect the input connectors. They can also be great to strengthen the box. Reflectors right around the throat area do make a difference in Hornresp, particularly when they affect the S1/S2 region.

One more note to the centerline discussion, soho54 has suggested that his corner method (which is what I'm using now) arrives at dimensions that produce Hornresp outputs that correspond to his measured results. I've tried a number of different ways, and there is just not enough difference to matter much. I do think it is worthwhile to enter a design into AkAbak prior to building, as most of the tapped horns that have multiple bends also end up having multiple tapers (flare rates), here AkAbak can give you a more correct simulation.

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Old 11th March 2011, 02:06 PM   #600
tb46 is offline tb46  United States
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Hi Djim,

It would be nice to see a complete design build around your ideas in Post #596, complete with a respective Hornresp input.

Regards,
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