I still think I'll do it. But I'm not used to be so much in the dark regarding the design. If it becomes clearer how the B200 fit in the 4x4 boards then I'll go ahead with it.
Meanwhile I think I might give it a try and build something that's been done here already.
So it's not just me thinking that the sound from these spirals is unlike anything else and amazing? I'm glad you like them. I put some high quality classical recordings through them and trios and quartets and chamber stuff sound amazing. The track slow like honey by Fiona Apple is just unbelievable. SWMBO finally came down to the rec room and she said they sounded really good and much bigger than they look.
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I got read up on this theory - do you have a good reference that describes the equation which you speak of? However, I purposely put sharp turns on the inner passages of my design to filter and low pass the horn output.
thanks for the input. basically, stereo isnt an issue for my laptop, just as long as both signals are present. as far as laptop sound goes, i also produce dance music, so kinda need a bit of kick to the sound for when i occasionally want to produce something on-the-run.. beyond that, its mostly for times when im playing a basic setlist (im also a mobile DJ) for friends at small friendly gatherings. so need somewhat decent volume as well.
generally speaking, since sealing my little horn, it sounds so much better than what i had just sitting on the carpet. (that you were spot on about! and i kinda knew in the back of my mind as well) but, doesnt quite have the low bass extension that im looking for.
the new horn design (according to your maths) @~1meter extends to 85hz, which still i think isnt enough, so ill redraw again and see if i can get more length. i think even another 25-35cm will get me into the 60hz range. (good luck with that hey... lol)
as for the computer inside the house, id love a set of reference speakers for doing mastering edits on. i have a small range of different speakers i could utilise for this. ill post up when im ready.
Klampykixx,
If you only have 1 meter, make a mass loaded transmission line rather than horn. You can reach down to 55 Hz easily by constricting the exit port (opposite of a horn) and stuffing the first 2/3 of the line densely. It helps to have a driver with high Qts to do this, read Bjorn Johanessen's TABAQ thread and you will see the performance that can be achieved with limited path length. If you don't need stereo, place both left and right drivers right net to each other at the 1/3 (from closed end), double the cross section and vent area and you should have it. Bjorn recommends that the cross sectional area of the transmission line be 4x the Sd. For two 3 in drivers, make the cross sectional area about 40 square inches x 36 inches long. See post 268 in this thread to get an idea. http://www.diyaudio.com/forums/full-range/88787-tabaq-tl-tang-band-27.html.
Regards,
Xrk971
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I just checked the local dolllar store. No foamboard. Michael's (on theotherside of the grocery store has 20x30" for $5 a sheet, 2x for ones with flat colour or some patterns including glittery metallic.
Each sheet good for 4 4.5" wide 30" strips.
CAD program says the short sporals are 1585mm (62.4"), the long ones 2234mm (88") so total of 7.638m = 301"
9 strips for the short, 12 for the long, 6 sheets = $30, $10 more for a colour or patterned board in the exit area.
I'll continue to check other stores.
dave
Each sheet good for 4 4.5" wide 30" strips.
CAD program says the short sporals are 1585mm (62.4"), the long ones 2234mm (88") so total of 7.638m = 301"
9 strips for the short, 12 for the long, 6 sheets = $30, $10 more for a colour or patterned board in the exit area.
I'll continue to check other stores.
dave
Very cool, I thought you had drivers on all five sides for an omnidirectional deal, so couldn't figure out how to do stereo on that. What 3 in driver did you use?
This thread has shown how to build these quickly and cheaply. Chris tells me it easier to build and try than futz around with the theory sometimes. That has already successfully been done twice in this thread.
And if the B200 does't work out, you can try other drivers.
dave
Are you coming to the mainland before Christmas? I have 16 boards available at a great price.
Then you can hear your FF125 babies before you decide. Did Rich send you an email?
Try Walmart. The $5 a sheet stuff has really thick paper and is a pain to cut with a razor actually - I think they put glass fibers in the foam and it doesn't cut cleanly.
Yes, use something you know from other projects so that when you listen to it for the first time, you know that it's the enclosure that is doing this - by 'this' I mean turn a driver you know and like into something almost unrecognizable from a take your breath away, love. My other recommendation is to get something with a definite high end that is strong. If you look at the TC9FD's SPL vs freq plot, it packs a wallop from 9k Hz on up, exceeding the nominal SPL rating by 5 to 7 dB and I think this helps to balance it in such a bass heavy enclosure.
the only foam board stock i found at dollarama was only an 1/8" thick and seemed to flimsy.i thought about laminating it but that kinda takes the ease of use factor out of the equation.
after a little experimenting with coroplast it does seem to have draw backs,for instance if you cut it parallel to the "ribs" it's almost impossible to bend (especially a small radius) but a perpendicular cut can be easily curled into a tight roll without alot of crinkling of the inner layer.
i may make an attempt with a thin plywood (front and back) and coroplast (cut the right way) for the inner spiral.
after a little experimenting with coroplast it does seem to have draw backs,for instance if you cut it parallel to the "ribs" it's almost impossible to bend (especially a small radius) but a perpendicular cut can be easily curled into a tight roll without alot of crinkling of the inner layer.
i may make an attempt with a thin plywood (front and back) and coroplast (cut the right way) for the inner spiral.
There is close to equal pressure on either side if the 'flimsy' wall of the horns so don't worry about it. Be concerned about what the driver is mounted to. The Sure-Ply I used my might end up needing a Supra Baffle to help stiffen things up, but as is it's a heck of a start. This is an evolving project.
Those are custom, hand made driver from little known remote town, Werdifucowee in central Africa.
Are you coming to the mainland before Christmas? I have 16 boards available at a great price.
No plans to travel to Canada before Christmas.
Happy 50th coming up i understand.
dave
Seems to me that routing a template for use in a pin router would be expedient. Create complimentary channels in the front and back to receive the strips of foam core.
Also, why not go ahead and make an mtm using 2 Vifas and an economical tweeter? ...or 4 in a diamond mmtmm surrounding the tweeter? They are small enough that lobing shouldn't be an issue. There's no reason you full-rangers should have all the fun.
Also, why not go ahead and make an mtm using 2 Vifas and an economical tweeter? ...or 4 in a diamond mmtmm surrounding the tweeter? They are small enough that lobing shouldn't be an issue. There's no reason you full-rangers should have all the fun.
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