open baffle rookie
Designer:
bhearts
Project Category:
Tower Speakers
Project Level:
Intermediate
Project Time:
8-20 Hours
Project Cost:
Under $100
Project Description:
i have never dealt with open baffle designs before, but i love how this turned out. wonderful, flat bass response that plays alot lower frequencies that i ever would have expected from an open baffle design.
Design Goals:
make a great sounding tower that i can give to my in laws while making them think i spent tons of money building them something that also looks good.
Driver Selection:
6.5 inch poly cone midbass speakers that are on the factory buyout deal because who doesnt want to make awesome towers using 4 dollar speakers and the goldwood 1″ softdome horn tweeters
Enclosure Design:
the face of the OB is 2 sheets of mdf thick so that i could round over the speaker exit to give it a streamline look. the face is 12×48 and the total height with stand is roughly 4.5 feet tall. i painted the rear non visible areas of the OB tower with a black spray paint, and the face of the tower was a grey with a nice clear poly over it. no real previous knowledge of open baffle designs so i just kinda winged it on the dimensions.
Enclosure Assembly:
I didnt have any huge set backs why designing these towers. i wired the speakers up in a series parallel design to end up with a 4 ohm impedance. toughest part was probably figuring out how to attach the face to the base plate, which i do think turned out looking quite fashionable. i really liked how the speakers mounted from the rear, are replaceable, and how the wiring worked itself out. its very rigid wiring design which helps because its all exposed to the elements.
Crossover Design:
i used the premade PE 5khz 8 ohm hpf crossovers for the tweeters. no filters on the midbass drivers.
Conclusion:
i dont think ill ever go back to enclosed towers ever again. the bass from this open baffle is the best thing ive ever heard. its so smooth and seems to extend down to the sub 50 range, although i have not performed any formal tests to verify this. i think these towers will look great in my in laws living room.
Project Parts List:
|
Part # |
Description |
Qty |
|
266-474 |
5 kHz High Pass 8 Ohm Crossover |
1 |
|
270-180 |
Goldwood GT-520 1″ Soft Dome Horn Tweeter |
1 |
|
299-609 |
6-1/2″ Poly Cone Midbass Woofer 4 Ohm |
1 |
To confirm your statement, “It is so smooth and seems to extend down to the sub 50 range, although I have not performed any formal tests to verify this ”, BaseBox 6 Pro predicts an f3 of 43 hertz for a infinite baffle with these drivers.
In a series parallel configuration the sensitivity of four of these mid-bass woofers is 90.7 dB 1W SPL, a good match to the soft dome horn tweeters output of 92 dB.
Whenever using a driver designed to work best in small sealed enclosure, in an open baffle, I always worry about exceeding X max. In this case, with the four drivers you are OK up to 27 watts for an output of 106 dB. That is loud enough for me.
I just picked up all of the gear to make these as they are quite nice looking and you really can’t beat the price 🙂 I have a couple of questions, can you provide some rough dimensions for the baffles? It looks to my eye that the woofers are about 1.5″ from the edges of the baffle, with 1-1.5″ separation vertically. Second, just a curiosity thing, why did you put the tweeters at the bottom? Was it just aesthetically pleasing, or is there acoustic reasoning behind the placement? Looking forward to my first foray into open baffle, thanks for the design!
the baffle is 12 wide by 48 high. i placed the woofers like 1.5 inches off center, and i believe it was 10 inch spaces between centers. originally i didnt plan on using a tweeter, but after a quick search i found out why my woofers didnt sound right by themselves. they are not a full range speaker. so the tweeter was an after though. i did want the tweeter closer to the middle of the baffle, so like between the 2 and 3 speakers. but there was not enough room to place one there without trimming the tweeters mounting plastic face. so it got mounted on the bottom, which is perfect listening angle at about 10 feet while sitting in a chair.