Without DSP an array like that is IMHO impossible. The spacing is what irritated me at first sight
Wiringwise it's not such a nightmare, you'd need a 12pin harting connector plus a 6pair speaker multicore
Regds,
Gerald
EDIT: plus an extra pair and 2 more pins for the sub...
You are correct, I am not building arrays. But I use that driver in a lot of other projects, so any info is welcome. Thanks.I don't think he is planning to build arrays, or are you, Pano?
About cutting the holes for the drivers
I have used a cheap fly cutter from General Tools for holes up to 6 inches or so. If you don't try to cut too fast, it works very well, and you can sharpen/profile the little cutter piece as needed. It needs to be used on a drill press, though. Google them and you will see that they are widely available.
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I have used a cheap fly cutter from General Tools for holes up to 6 inches or so. If you don't try to cut too fast, it works very well, and you can sharpen/profile the little cutter piece as needed. It needs to be used on a drill press, though. Google them and you will see that they are widely available.
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I didn't catch those tweeters... I still need to follow the link. Had to run off to work earlier
.Due to the nature of a curved array the spacing would be a little less important in the exact sweet spot though.
Do you still have plans for OB arrays?
Do you mean something like this: Heavy-Duty Circle Cutter | Rockler Woodworking and Hardware
They make really nice circles in MDF and are infinitely adjustable, but you need to go slow to avoid heating up the blade too much and burning the wood.
My buddy Rick Craig of Selah Audio has done a similar array called the Symmetrica which has a dual line of small woofers separated by a line of ribbon tweeters. Some discussion is on line about this approach. Click on the compressed image displayed above to see the actual view.
See Rick's gallery at:
Gallery ? Selah Audio
Jim
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wesayso - did you ever consider a curved baffle? I know the concept of laminated sections doesn't lend itself to that design, but just curious if it was a consideration at some point. For my own build, it occurred to me that I could potentially do a "sectioned" curve perhaps in thirds or fifths, so just wondering what your thought process might be on it.
I wish! But building a demo tower is costly. I have a small sealed array of 9 local drivers, I'm thinking of just opening the back and see / hear what a 9-driver small OB array does.
That's the beast. Walmart has it for under $20. Heat buildup is slower in baltic birch. Just lift for cooling after 4-5 seconds.
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My buddy Rick Craig of Selah Audio has done a similar array called the Symmetrica which has a dual line of small woofers separated by a line of ribbon tweeters. Some discussion is on line about this approach. Click on the compressed image displayed above to see the actual view.
See Rick's gallery at:
Gallery ? Selah Audio
Jim
I know the one from Selah Audio well. With the tweeter line in between it makes much more sense. I should have clicked the link in Halair's post before replying.
Yes, I did consider a bend array. I considered both the focussed array and the backwards bent "Keele" style arrays.
I didn't opt for the focussed array because I wanted a large pleasant listening area. The focussed array would work very well at one spot.
The Keele array should be able to get that wide listening area, but bend backwards while using full range drivers didn't seem like a smart option. You're creating more problems than you solve by having larger distances between drivers and ear of the listener.
That's the reason why, after a considerable amount of thinking I ended up with the solution in the middle. Trusting I could use DSP to get me closer to the ideal.
I'll share a (twisted) brain wave:
It still sort of works like Keele's array, as long as the array is large enough and you factor in floor and ceiling reflections. Think of the arrays as being part of one huge endless circle of enormous diameter. The shading (and time delay) is the floor and ceiling reflection. DSP gets the FR plus Phase back in line. A comment from Tom Danley (about in-living-room floor to ceiling arrays) confirmed I wasn't the only one with crazy visions like that.
Way off the path here, showing my twisted mind
but these ideas/visions entered my mind while considering my options. I've studied all arrays I could find online. I had backup plans with single tweeters, alternative wiring schemes for shading (with or without passive components to only shade higher frequencies) and even rows of tweeters were in the back of my mind.Luckily this DSP/array combo worked out way better than I could have imagined.
The beauty of this Forum is we get the chance to ask questions to people like Danley, Geddes, Griffin, Smith and many more...
I fell in love with the look that member Koldby showed with his all aluminium enclosure.
That made me look into the option of the back mounted drivers. After some searching on the net I found someone on a German forum, using the TC9 in a FAST setup. He showed measurements, comparing a back mounted TC9 to the same driver flush mounted.
The back mounted driver, with a fillet on the hole showed better measurements, both on axis (flatter around 8-9 KHz) and more similar behaviour out to about 30 degree off axis. That sealed the deal for me. Sadly some of the pictures in that project disappeared. I should have copied those graphs.
Here's a couple of pictures to show the cone, flowing into the round over and enclosure shape:
And
I wanted to create an as seamless transition as possible, no sharp edges.
Flowing into the overall enclosure shape:
I did mention I love the look of it too, so that helped.
That made me look into the option of the back mounted drivers. After some searching on the net I found someone on a German forum, using the TC9 in a FAST setup. He showed measurements, comparing a back mounted TC9 to the same driver flush mounted.
The back mounted driver, with a fillet on the hole showed better measurements, both on axis (flatter around 8-9 KHz) and more similar behaviour out to about 30 degree off axis. That sealed the deal for me. Sadly some of the pictures in that project disappeared. I should have copied those graphs.
Here's a couple of pictures to show the cone, flowing into the round over and enclosure shape:
And
I wanted to create an as seamless transition as possible, no sharp edges.
Flowing into the overall enclosure shape:
I did mention I love the look of it too, so that helped
.
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Looks great! Do you remember if the German forum dimensions were similar? I'm considering a 3/4" round over on a 3/4" thick baffle. Eyeballing yours looks roughly like a 1/2" round over on a 1/4" baffle? So wondering if that would be a significant difference. I could do a 1/2" baffle as well I suppose. Should probably be ok considering the baffle width is only a few inches.
Panos, you can use 3" hole saw, then kiss the edge off the corner about 1/16" with a 45 chamfer bit, if necessary. I test-fit the driver into 3" (hole saw) hole last week, it fit perfectly. I guess every hole saw has some tolerance since they are rather crudely made.
I got my 64 drivers to make 9 foot arrays. Designing the boxes now.
I got my 64 drivers to make 9 foot arrays. Designing the boxes now.
My front baffle plate thickness is 6 mm. The radius is bigger and flush with the front, 8mm to be exact.
If I remember correctly the round-over used in that example on the German site was 9 mm. I've linked to it somewhere in this massive thread. I don't recall the thickness of the baffle or if the driver was inset into the baffle from the back.
I also remember xrk971 running some simulations for me in Akabak on the effect of that waveguide shape (using my dimensions). I wanted to keep it subtle, basically "just about" hidden behind the surround when looking 'out' from the cone profile point of view. That's how I determined my own dimensions.
With a thicker front baffle I'd use an even bigger round-over. However keeping the close driver spacing will result in removing more material in between drivers.
I wouldn't want to "create" something resembling a front cavity. Just some wave guide like shape, flowing continuous from the cone/surround outward.
The round overs already "meet" each other in the middle with my thin baffle.
Maybe I should put up a warning: I'm always overthinking things (lol).
If I remember correctly the round-over used in that example on the German site was 9 mm. I've linked to it somewhere in this massive thread
. I don't recall the thickness of the baffle or if the driver was inset into the baffle from the back.I also remember xrk971 running some simulations for me in Akabak on the effect of that waveguide shape (using my dimensions). I wanted to keep it subtle, basically "just about" hidden behind the surround when looking 'out' from the cone profile point of view. That's how I determined my own dimensions.
With a thicker front baffle I'd use an even bigger round-over. However keeping the close driver spacing will result in removing more material in between drivers.
I wouldn't want to "create" something resembling a front cavity. Just some wave guide like shape, flowing continuous from the cone/surround outward.
The round overs already "meet" each other in the middle with my thin baffle.
Maybe I should put up a warning: I'm always overthinking things (lol).
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Man, those baffles are amazing. No matter how many times I see them.
I am concerned about creating a "front cavity" as you mention with 3/4" thick baffles if using a ~8mm round over. And the intersection of round overs may look weird at 3/4" round over. Using 1/2" baffles with perhaps something a little less than 1/2" round over might work ok though.
Also, what size is the actual hole itself? Or more directly, a 3" hole saw should work fine, yes?
I am concerned about creating a "front cavity" as you mention with 3/4" thick baffles if using a ~8mm round over. And the intersection of round overs may look weird at 3/4" round over. Using 1/2" baffles with perhaps something a little less than 1/2" round over might work ok though.
Also, what size is the actual hole itself? Or more directly, a 3" hole saw should work fine, yes?
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I'm suggesting to use a bigger round over than the actual baffle size. Almost hiding the round over behind the surround as an extension of the cone.
My 77 mm hole (see how I didn't round over the complete hole with that bigger radius? It's more open that way) would be slightly bigger than a ~ 3" hole in imperial standards. The round over would amount to that 76 mm figure. So I opened up the hole 1 mm. It may be hard to tell but the dimensions follow the round over. I used a template to make this using 2 hole sizes, 76 mm for the round over bit to follow, 77 mm to cut the original hole. My template had another 78 mm hole in it for the back baffle I use, that hole fits the back side of the driver.
My 77 mm hole (see how I didn't round over the complete hole with that bigger radius? It's more open that way) would be slightly bigger than a ~ 3" hole in imperial standards. The round over would amount to that 76 mm figure. So I opened up the hole 1 mm. It may be hard to tell but the dimensions follow the round over. I used a template to make this using 2 hole sizes, 76 mm for the round over bit to follow, 77 mm to cut the original hole. My template had another 78 mm hole in it for the back baffle I use, that hole fits the back side of the driver.
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Another interesting thread from Patrick Bateman. I love this guy for always bringing up interesting discussions and thoughts: http://www.diyaudio.com/forums/multi-way/303155-what-do-roundovers-do.html
His original thread on DIYMA made me redesign my tweeters in my car. It was also a big influence on how my array's shape ended up. It made me read up a lot on all kinds of speakers and their ability to disappear.
My conclusion from all of that reading was: You either need very wide baffles "or" very small baffles to have the best shot at that disappearing act.
My choice was to use the smallest version, with round overs to aid in that disappearing act. I made sure to make the speakers smaller than an averaged sized head.
There you have it, another one of my crazy brain waves out of the bag. I did mention I had a lot of reasons to do what I did. (there's even more reasons why, dare I mention those?)
Thanks to member Patrick Bateman, appropriate handle for someone with crazy out of the box ideas and theories.
His original thread on DIYMA made me redesign my tweeters in my car. It was also a big influence on how my array's shape ended up. It made me read up a lot on all kinds of speakers and their ability to disappear.
My conclusion from all of that reading was: You either need very wide baffles "or" very small baffles to have the best shot at that disappearing act.
My choice was to use the smallest version, with round overs to aid in that disappearing act. I made sure to make the speakers smaller than an averaged sized head.
There you have it, another one of my crazy brain waves out of the bag. I did mention I had a lot of reasons to do what I did.
(there's even more reasons why, dare I mention those?)Thanks to member Patrick Bateman, appropriate handle for someone with crazy out of the box ideas and theories.