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GM
GM
thanks for the time info.
Dave, I’m going to take your advice on not going with the two lines. Here is my drawing for one line about 37 inches in a smaller enclosure. Since I’m doing this for experimentation of those 5 drivers, modeling itwon’t help their Fs’s range from 45fs to 125fs. Do you think the 10:1 taper ratio is ok for the qts range between .46 to.89 or should I drop it back a little?
Does it look like I have enough space behind the cone area(about 1.5 inches and then then beginning CSA?
Thanks
Dave, I’m going to take your advice on not going with the two lines. Here is my drawing for one line about 37 inches in a smaller enclosure. Since I’m doing this for experimentation of those 5 drivers, modeling itwon’t help their Fs’s range from 45fs to 125fs. Do you think the 10:1 taper ratio is ok for the qts range between .46 to.89 or should I drop it back a little?
Does it look like I have enough space behind the cone area(about 1.5 inches and then then beginning CSA?
Thanks
I don’t model our TLs, Scott does. But from comments that have been made those Qts are best for straigh pipes for the lower Qts and Voigt pipes for the higher Qts. A Voigt usually needs to be mass loaded for best performance.
I doubt that a single line will be a good experiment for such a range of drivers. If that driver is to scale, that line looks far too small, even for an aperiofic midTL (not an ideal line either).
With the taper, tuned to below 87 Hz. Martin has suggested a good starting point when you are modeling is 3 x Sd for initial CSA, but in the end it is related to Vas, Fs, and Qts.
dave
I doubt that a single line will be a good experiment for such a range of drivers. If that driver is to scale, that line looks far too small, even for an aperiofic midTL (not an ideal line either).
With the taper, tuned to below 87 Hz. Martin has suggested a good starting point when you are modeling is 3 x Sd for initial CSA, but in the end it is related to Vas, Fs, and Qts.
dave
If the box inside =10 x 10 x 5, then the CSA of the line opening will be 1.25 x 10 =12.5 sq in = 80 cm2 sothat is 2.5x sd not 3x sd. So if I use your recommendation, then I would need to make the box about another 1/2" in height = 5.5" - then CSA would be 3x+. That is nice to know.
About the line being to small. Do you mean in length or volume?. It measures about36-38 inches baffle to baffle and the volume goes from 16 sq in to 1.6 sq in (just about 3/16 x 10) slot.
With those figures, does it make sense to experiment with it?
About the line being to small. Do you mean in length or volume?. It measures about36-38 inches baffle to baffle and the volume goes from 16 sq in to 1.6 sq in (just about 3/16 x 10) slot.
With those figures, does it make sense to experiment with it?
Not my recommend, a suggestion from Martin when starting one of his MathCad models
Volume.
I’d be experimenting in a modeler to start.
dave
PS: The Font, Color, and Size tags are for emphasis, not the body of the post. It is a lot of work cleaning up your posts.
dave
dave
Sorry about that - not sure what I'm doing wrong - I use Msword to compose it with TimesRoman, font 12 and automatic color (black) and just copy and paste in this forum. The above characters, I just typed in using the forum's message box.
In this sentence, I copied in from mswork, font = arial, size =12 andblack font. Does this sentence need cleaning?
In this sentence, I copied in from mswork, font = arial, size =12 andblack font. Does this sentence need cleaning?
Yes that sentence needs cleaning. That does explain why it happens so often, and looks so ugly. The formatting is being carried over from Word. If you use a text editor, or maybe save the file as text, it likely will not come over.
dave
dave
I have modeled each of those 5 speakers and a few more and you are right. The CSA varies a lot, basically from 19 to 36 sq in and the line lengths from 17 to 46 with the F3 from 33 to 91. The good news is that they all will fit in the 550 cu in box. So I will design three or four strip inserts to drop into the box that varies the length with the CSA.
One last question: In the picture, assuming I should start the CSA measurement at A, do I need the line labeled B to keep the line somewhat tapered or can I leave it off for a larger "chamber?" Thanks Dave, you have been a great teacher!
One last question: In the picture, assuming I should start the CSA measurement at A, do I need the line labeled B to keep the line somewhat tapered or can I leave it off for a larger "chamber?" Thanks Dave, you have been a great teacher!
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I don’t understand your question. BTW starting CSA is above the driver, so yours gets larger then shrinks.
dave
dave
Of course, see the new picture with the slanted line reversed. Now, the same question which should be clearer. Do I need the line labeled B or can I eliminate it. The taper is less then perfect but I have a bigger chamber vol for the speaker. Which is better and do you see anything that will make the design better?
By the way, what does BTW mean?
By the way, what does BTW mean?
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On my prototype for noisePlank, I found that when I put a 3/8" thickness of felt in immediately behind the driver I couldn't get the driver to sit flat, so I added a little baffle thickness. Space between the rear of the driver and the felt was perhaps 3mm. It worked fine.
So I think 1.5 inches is oodles.
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