20-30hz tapped horn for studio with ande drivers

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#61
Hi reminence,

Post #58: "...By baffle do you mean the sheet directly in front of both drivers?"

Yes, that's correct. Use screws around the perimeter into the box sides and top every 6 to 8 inches. If you are having problems with a screw thread stripping out, redrill the hole somewhat larger (e.g.: 3/8" x 1-1/2" deep), and glue in a wood dowel. Use weather stripping for sealing, e.g.:

Speaker Gasketing Tape 1/8" x 3/8" x 50 ft. Roll 260-540 , or similar.

Post #58: "...as to what damping material to use im not sure what we have over here."

Apply damping material as close as you can to what is in the drawing, and use polyfill. For general interest-and sources in Australia-take a look at this thread:

http://www.diyaudio.com/forums/multi-way/84669-what-polyfill-stuffing.html

Regards,
 
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#66
Hi Dan,

I have gone through some of the Google SketchUp tutorials you pointed out, and it looks a lot easier than what I remember from trying to do 3D in AutoCAD in the early 80's. We got it done, but had to do some simulations by letting the computer run through the night. I still have to look into the custom input device you pointed out. Thanks.

Regards,
 
#68
Finally was able to download hornresp 😀

would it be ok to drive the box at 700wrms or 73V as at that voltage it only just touches its xmax (assuming I high pass at 20hz and low pass at 80hz)?

Also is there any point to running the drivers in series vs parallel providing my amp if perfectly capable of 2ohm?
 
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#69
Hi reminence,

That would be more a question for the people who have build the 212 Kraken with the JBL GTO1214, or a JBL engineer. See if anyone in Petter's thread has done any high power testing of these drivers.

I think the power specs for this type speaker are generally optimistic, but they claim 350Wrms and 1400Wpeak, so according to JBL you would be safe. Particularly with music. Always approach the higher power level carefully, I recommend against using sine waves for high power testing.

I practice, if you want more output you are better of with a second enclosure. That would open up more placement choices, and make it easier to dial in the room.

Have fun with Hornresp, it's a great tool.

Regards,
 
#70
fair enough! I doubt I would ever need the spl of 700w but i was simply keen to see what maximum spl would be when simulated, which for 700w is about 120db 😀

Is interesting to note that when the drivers are simulated in parallel it is about 4db above that of series wired!
 
#71
Hi reminence,

If you double-click on Eg a window opens up that allows you to enter power and impedance. If each is a 4-Ohm driver, than 2 in series are 8-Ohms, and two in parallel are 2-Ohms. The SPL will be the same @ the same power level with the correct impedance. Sorry, still no free lunch. But at least you're learning Hornresp. 🙂

By the way speakers work fine in series connection, provided they are the same.

Regards,
 
#76
Drivers on there way, pick up sheets during next week and building next weekend 🙂
I hope to get most of it done in one day and I have a woodworker helper who also has the tools.

Not long now and Then I will measure it, On that note does anyone have any software to recommend to measure the box (it must be able to use my calibration file ".cal")?
 
#80
Calibrated my sound card (fa-101) and mic (RTA-m) and did a REW room measurement right where my head would be and got what I would call a strange plot. Far to wild than I thought it would be (without sub).

Its just my studio (JBL lsr2300 8 inch's) in stereo with no eq. It seams to have massive variations of up to 50db within a few hz throughout the graph and I think I'm doing something wrong here!

An externally hosted image should be here but it was not working when we last tested it.


Edit, NVM I did not add any smoothing which is apparently what you would normally do.
 
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