Yes... the others range was a little higher...
AND THE PRICE WAS 40% HIGHER! Those are nearly a DOLLAR!
I just got back from a friends house bandsawing off the two obtuse angled bits... keeping the mounting hole bits, but losing some other stuff (cap & harness plug). They will now go to a 2.270" C/C distance, compared to 2.610" before.
chipco3434 said:
24 tweeters.....all running up to 20k.....i would not recomend that. at 20,000Hz your c-c has to be .0165m (1.65cm or 0.65"). that means the domes have to be about 0.5" dia and touchig each other....before interference/cancellation.
one way out is to use what polk did on it's SDA seris in the 80s. run 1 tweeter fullrange and roll the rest off (LP). only i dont see much merit to this.
Same config as mine
I've got the same mid/tweeter combo in an array http://www.ryoshu.com/line_array_full.jpg
I'd suggest using a rotary to remove the phase shield, and use "rope caulk" to seal them to the baffle. The rope caulk is easy to remove if you mess up, and you probably will (that's *alot* of speakers!). You'll also want to trim the outside plastic on those tweeters to get the closest c2c you can. With an even hand, you can get them to stack flat pretty nicely.
/edit
I'd strongly suggest the more expensive but smaller buyouts. Comb filtering is noticable on the larger Onkyos. I would have built new cabinets for another set with the smaller tweeters, but I can't gather the motivation to cut that many holes agains.
I've got the same mid/tweeter combo in an array http://www.ryoshu.com/line_array_full.jpg
I'd suggest using a rotary to remove the phase shield, and use "rope caulk" to seal them to the baffle. The rope caulk is easy to remove if you mess up, and you probably will (that's *alot* of speakers!). You'll also want to trim the outside plastic on those tweeters to get the closest c2c you can. With an even hand, you can get them to stack flat pretty nicely.
/edit
I'd strongly suggest the more expensive but smaller buyouts. Comb filtering is noticable on the larger Onkyos. I would have built new cabinets for another set with the smaller tweeters, but I can't gather the motivation to cut that many holes agains.
tweeter installation
I trimmed the all the plasic last night and Dremeled off a few of the phase shields on the tweeters.
I going to run the Onkyos on this set. I have enough of the 4" drivers to build a second set with cherry panels & birch stiles. For project 2, I will go with the Dayton planar tweeter. As for back mounting, that was my plan. I anticipated routing a substantial radius on the tweeter baffle holes. What are the technical advantages of a 45 over a bevel for these holes?
Let's talk about crossovers!
I trimmed the all the plasic last night and Dremeled off a few of the phase shields on the tweeters.
I going to run the Onkyos on this set. I have enough of the 4" drivers to build a second set with cherry panels & birch stiles. For project 2, I will go with the Dayton planar tweeter. As for back mounting, that was my plan. I anticipated routing a substantial radius on the tweeter baffle holes. What are the technical advantages of a 45 over a bevel for these holes?
Let's talk about crossovers!
I'd say you want a pretty steep-slope crossover on this project, like 4th order or something. Look at the response graphs of your 4-inchers and the Onkyo tweeters and find a crossover point where the responses are still reasonably flat. A 4th-order crossover will have lots of components, though. Be ready for that.
I'd say find as big of a roundover bit as you have and go over all the tweeter holes, to make a sort of waveguide, with some horn loading and directivity control. I don't know how good of an idea this is. I imagine some of the other guys can give you better ideas about how to do effective waveguides.
In addition, if the Onkyo tweeters just plain don't work, you can cut out the section of cabinet that has waveguides and put a piece of that plywood over the hole, round-over all 4 of the edges that don't mate up with the main baffle, and then stain the board the same color that those reddish cabinet trim edge thingies are stained. Then you can get a number of the Tang Band 25-302S neodymium tweeters ($13.96 ea., PE #264-804). They have a small faceplate that is truncated on two sides, making them "perfect for line arrays!(tm)" You could get away with four or eight per side, and then do some frequency contouring on the NSBs so that in order to match the sensitivity of just four 25-302S tweeters, the NSBs need to be padded down a few dB, and then you could have it so that the slope of that filter compliments the bass rolloff of the NSBs, so you get deeper bass extension, at the expense of just a little sensitivity. Just an idea.
I'd say find as big of a roundover bit as you have and go over all the tweeter holes, to make a sort of waveguide, with some horn loading and directivity control. I don't know how good of an idea this is. I imagine some of the other guys can give you better ideas about how to do effective waveguides.
In addition, if the Onkyo tweeters just plain don't work, you can cut out the section of cabinet that has waveguides and put a piece of that plywood over the hole, round-over all 4 of the edges that don't mate up with the main baffle, and then stain the board the same color that those reddish cabinet trim edge thingies are stained. Then you can get a number of the Tang Band 25-302S neodymium tweeters ($13.96 ea., PE #264-804). They have a small faceplate that is truncated on two sides, making them "perfect for line arrays!(tm)" You could get away with four or eight per side, and then do some frequency contouring on the NSBs so that in order to match the sensitivity of just four 25-302S tweeters, the NSBs need to be padded down a few dB, and then you could have it so that the slope of that filter compliments the bass rolloff of the NSBs, so you get deeper bass extension, at the expense of just a little sensitivity. Just an idea.
If you have an adjustable circle cutter that you put in your drill or drill press, what you can do is cut the hole the regular way. (cut all the holes first but dont remove the material from the sacrificial piece you are using undernieth it) Then rotate the cutting piece from the circle cutter and rotate it 180 degrees and extend the length about a quarter inch, now put the drill piece back through the same hole as before when drilling and you will have nice 45 degree 'flares' to mount the tweeters into. (Note: this only works with thin material like 1/4'' hdf)
Just an update on the line array cabinet project...
Last night I hole sawed 24 1-3/4" holes on the face of the speakers at 2.270 centers. I followed with a 1/2" radius routing bit with just enough clearance to provide bearing surface for the ball bearing router guide. It produced a very nice looking horn wave guide. I have absolutely no idea how it will affect the sound, but I have read that right angles aren't the hot setup.
After the holes were routed, I brush painted the exposed MDF with black acrylic. Looks sharp.
Regarding the 4th order Butterworh crossover suggestion, is that principally to avoid the phase shifts associated with other lower order crossovers? The circuitry doesn't bother me as much as the price. As for the learning experience, I will first install just a simple high pass filter for initial testing. This is on the recommendation of some guy called Nelson Pass who has posted on this forum. His statement was that he starts with a high pass and starts playing from that point. Good for Nelson... good for me!
So on my way to Milwaukee, I'll stop by and pick up some caps in the range of 4-7 muf.
Cool?
Last night I hole sawed 24 1-3/4" holes on the face of the speakers at 2.270 centers. I followed with a 1/2" radius routing bit with just enough clearance to provide bearing surface for the ball bearing router guide. It produced a very nice looking horn wave guide. I have absolutely no idea how it will affect the sound, but I have read that right angles aren't the hot setup.
After the holes were routed, I brush painted the exposed MDF with black acrylic. Looks sharp.
Regarding the 4th order Butterworh crossover suggestion, is that principally to avoid the phase shifts associated with other lower order crossovers? The circuitry doesn't bother me as much as the price. As for the learning experience, I will first install just a simple high pass filter for initial testing. This is on the recommendation of some guy called Nelson Pass who has posted on this forum. His statement was that he starts with a high pass and starts playing from that point. Good for Nelson... good for me!
So on my way to Milwaukee, I'll stop by and pick up some caps in the range of 4-7 muf.
Cool?
Holy *******.
I can't beleive other people are doing this too. I just go 50 of those little tweeters and finally decided on the 4" as midranges. My plan is to mate them with a Peerless 10" in a TL or ML-TL.
I've got to ask you guys, what about the goofy tweeter assembly. What is the best way to mount them and get rid of the phase sheild? I don't trust my dremel skills enough to lop of the phase sheild. Is there an easier way?
I can't beleive other people are doing this too. I just go 50 of those little tweeters and finally decided on the 4" as midranges. My plan is to mate them with a Peerless 10" in a TL or ML-TL.
I've got to ask you guys, what about the goofy tweeter assembly. What is the best way to mount them and get rid of the phase sheild? I don't trust my dremel skills enough to lop of the phase sheild. Is there an easier way?
Prepping the tweeters.... I call it shucking oysters. Hold the tweeter face down in the left hand. Plae thumb against side of connection jack and give it one big push. Now thats gone. Still holding the tweeter in the left hand, snip off the wires of the jack with diagonal cutters. Now snip the terminal of the yellow wire that holds the cap. Move the tip of the cutters under the cap and pry upwards against the cap using the plastic case as a fulcrum.. it's loose. Wiggle the cap so it fatiques at the red terminal junction. Finish by pulling the wires out of the strain relief. Strip wires and serve on plate! ~ About thrty seconds prep time.
You can Dremel the shields off. If you are shakey, baby diagonals will clip them off also.
The speakers are in the living room and connected. I'll try to get a photo today or tomorrow. Start to finish... (who's counting a decent crossover?) about ten days.
You can Dremel the shields off. If you are shakey, baby diagonals will clip them off also.
The speakers are in the living room and connected. I'll try to get a photo today or tomorrow. Start to finish... (who's counting a decent crossover?) about ten days.
tweeter prep
I forgot to mention on the last thread... The tweeters are first prepped by cutting off the excess plastic on the housing. Specifically, the plastic that increases their center/center distance is removed. We made a wooden jig ~(fixture/template) that held pinned the tweeter through the mounting holes. This we fed through a band saw to trim about 0.200" on each side.
I forgot to mention on the last thread... The tweeters are first prepped by cutting off the excess plastic on the housing. Specifically, the plastic that increases their center/center distance is removed. We made a wooden jig ~(fixture/template) that held pinned the tweeter through the mounting holes. This we fed through a band saw to trim about 0.200" on each side.
MDF is medium density fiberboard, generally in 3/4" thickness (~19mm). It's wood chips and saw dust mixed with glue. It is available with a variety of veneers, usually with one "good" side and one "bad" side, each about 2mm thick Pretty vs. not so pretty. This one is birch, unstained and laquered. The stiles (vertical rails) are also birch, but stained. The construction is splined & glued. Both speakers are constructed from a single sheet of 4' by 8'.
I'll post pictures today.
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