I am not aware of any sub $100 open baffle projects that have been posted. The most economical open baffle projects I have seen are Paul Carmody's Aether variants.
Do these need to cover bass frequencies as well? What are your size limitations?
Depending on the answer to that question there are a couple of options for you, but none with pre-determined results.
One option is to build a two way box-based design, keeping the baffle dimensions but not the whole box depth. The dipole correction may then be applied at the line level to your amp using a passive crossover. The low frequency ability of this type of system will be limited compared to the box-based design.
If you want full-range output from an open baffle design and you want to build a pair for under $100 then there is only one obvious solution to me. A low cost full range driver couped with a low cost 15" woofer on a relatively large baffle. Martin King used this arrangement in his open baffle designs and his white papers are worth a read. He uses more costly drivers, but the approach is still valid for your budget.
No, they don't need to handle bass frequencies. I'd like to stick to a between a 4 and 6 1/2 inch woofer. I'd like to keep it no bigger than a typical two way w/ a 6 1/2 inch woofer, as far as the size of the baffle.
No, they don't need to handle bass frequencies. I'd like to stick to a between a 4 and 6 1/2 inch woofer. I'd like to keep it no bigger than a typical two way w/ a 6 1/2 inch woofer, as far as the size of the baffle.
You cannot get there from here. Read the white papers on Martin J. King's website.
Last edited by Jim Griffin; 07-12-2011 at 04:30 PM.
Reason: correction
I just heard these open baffle speakers at the Capital AudioFest in Maryland, and they are excellent. They are called Surreal Sound, and I think they are about $10,000 a pair.
I was wondering if it was possible to make somthing even one quarter as good, just concentrating on the tweeter and a mid bass, and use a conventional sub if needed. I'm not much on bass so a sub might not be necessary for me.
To put an example with Jim's point: I built a pair of desktop dipoles back in college that used a beast of a 6.5" woofer: the Adire Audio Extremis. This woofer is capable of +/- 12mm of excursion and can displace as much air as some 10" woofers. Even that woofer could not produce meaningful bass from a standard sized 6.5" 2 way baffle.
If you are willing to stretch the baffle size a bit, you could build something similar to Linkwitz' dipole protos, but you would be exploring new territory trying to keep it under $100.
Edit: Just saw your response. If you can get the subwoofers (you would need a pair of them) close to the dipole panels then you might have a shot. With a standard 6.5" woofer you could probably stretch the crossover as low as the 200-300Hz range. You would not need much dipole correction at that crossover frequency. In this arrangement, you might be able to hit your $100 mark for the midrange/tweeter panels, but obviously the subs would be extra.
The idea there is to take a high q driver (1.3 in this case), put it on a narrow baffle (just wide enough to give you the low end frequency response you need) and... that's it. The driver qts and baffle width are critical and need to complement each other but it's very easy to model with software of your choice. For under $100 this is going to be one of very few options. It doesn't have to be a coax driver and ideally it would be crossing over around 700 hz to a "fullrange" tweeter to minimize certain compromises. This type of speaker NEEDS to be high passed to protect it, and even then it's not going to extremely loud. But it doesn't need any dipole correction circuits which can eat several times your budget by themselves.
So it's possible but the bass driver selection is critical if you want flat response on a budget. If you need to keep it under $100 look for car audio drivers, the old GM/Delco 6x9's from the last couple of decades are perfect for narrow baffle OB and are cheap or free (I've got a bunch from old cars and they will easily get low enough to cross to a sub). Car audio coaxes with very high qts, like in the linked project are an option, but the dipole hump is a problem since the speaker crosses over so high, and the crossover is usually just a single NPE in drivers in this price range, so if you use a coax you won't be able to take out the dipole hump with the crossover.
If you could double the budget it would open up a world of possiblities but the ideas here will get your foot through the door of the OB world for less than $100 if that's what you need to do.
Don't even try
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If I were tinkering for fun, and under a budget like yours, I'd buy something like the TBs about one or two from the top of the classifieds, or the $12 TBs that are on sale at Madisound and then get a pair of 15" GW or another eBay 15" driver you can find specs for and use a simple first order high and low pass to get by. At least it will be fun. You might be surprised.
Or, if you want to use smaller drivers, you could extend your budget a little and grab a pair if those Aurasound subs on the Madisound specials page along with those TBs I mentioned. That would be $150 or so, but better than most 6" drivers.
Haven't heard 'em but if you have free wood laying around these just fit your budget: http://wildburroaudio.com/projects.php
...if you're not looking for the high-tech look!
Anyone know of any open baffle 2 way projects w/ parts around $100 or less for a pair?
A little more that $100 a pair but I designed this small dipole a few years ago. I never released it because of the limited SPL. I was actually a very nice small dipole.
John k.... Music and DesignNaO Dipole Loudspeakers. "We have no right to assume that any physical laws exist, or if they have existed up to now, that will continue to exist in a similar manner in the future." Max Planck
Thanks John, that's just along the lines of what I was thinking of, in terms of size and appearance. A little more than I'd hoped to spend, but it might be the way to go. I think they would look terrifc.
Have you looked at Aurasound drivers on sale at Madisound. You could do an Aethers type build with 4 of the NS525 (at $8 each, $32), 2 of the NS-8 in a small ported box to provide bass (at $19.5 each, $39), and because the NS-525s go pretty high, maybe cross high and use the Dayton 3/4 neos, or the Sinar Baja TWD25 (at $5.85 each, or $11.70). Total cost of speakers, $82.70.
May have to go a bit over budget with crossover parts, but likely could use simple crossover and could stay pretty close.
Inexpensive open baffle
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Originally Posted by daveinva
