Hello! This is Soldermizer. Those who know me (insert sigh) know that I am interested in many items and probably fortunately, don't try and build all of them. Search for Frankenclosure, Polluto and others and you'll find my recent ill builds. To be fair, the Frankenclosure (a 2' cube sub) was actually built and works ok, after two failed tapped horns. My idiotic plans for current feedback have been limited to the purchase of pencil leads (envisioned to make sensing resistors).
Latest project, just ideas for experimentation really: I've been reading some of the line array threads and this is something I want to try. Rather than use quality components, which you know is not my style, I want to try something using material on hand. Being a Bose 901 (series I, II) afficionado ("victim"?) I have available quite a few drivers that could -- at least in theory -- serve in a line array. I'm sure this has been done but haven't found any mentions of it yet.
Labor: that would be the biggest investment (since I already have enough ? drivers and EQ). How about some plans, though? I'd like to build the unit in modules of perhaps 4 drivers and make them stackable. Perhaps from my "medium" (coroplast signs), or even xrk971's foam core? Easy to work with and if it's a disaster (likely!) only some adhesive removal and de-soldering is required.
How big the array? I probably don't have enough to make a floor to ceiling array. Furthermore, my living room has high angled cieling. For getting a taste, 8 or 16 drivers per side? If building out of wood, how does one counter-balance the far side of the enclosure?
Since building in modules is a goal, here is my idea for rev 0: make a module from a single sheet of coroplast (about 18x24" IIRC) in a triangle prism shape; eyeballing looks like this will easily hold 4 drivers vertically.
Latest project, just ideas for experimentation really: I've been reading some of the line array threads and this is something I want to try. Rather than use quality components, which you know is not my style, I want to try something using material on hand. Being a Bose 901 (series I, II) afficionado ("victim"?) I have available quite a few drivers that could -- at least in theory -- serve in a line array. I'm sure this has been done but haven't found any mentions of it yet.
Labor: that would be the biggest investment (since I already have enough ? drivers and EQ). How about some plans, though? I'd like to build the unit in modules of perhaps 4 drivers and make them stackable. Perhaps from my "medium" (coroplast signs), or even xrk971's foam core? Easy to work with and if it's a disaster (likely!) only some adhesive removal and de-soldering is required.
How big the array? I probably don't have enough to make a floor to ceiling array. Furthermore, my living room has high angled cieling. For getting a taste, 8 or 16 drivers per side? If building out of wood, how does one counter-balance the far side of the enclosure?
Since building in modules is a goal, here is my idea for rev 0: make a module from a single sheet of coroplast (about 18x24" IIRC) in a triangle prism shape; eyeballing looks like this will easily hold 4 drivers vertically.
Hahaha, the sudden burst of interest in line arrays makes me smile. They were the big thing in 2005, 2006 (remember Pipe Dreams?) and this feels like a retro boom of interest.
I'd say go at least for 16 drivers per channel. Are they all created equal? The Bose speaker drivers I mean. If it were up to me I'd run impedance checks on all chosen drivers to see where you're at. If they are equal enough it could be a fun project.
Hand picked 32 drivers should get you there, That's a lot of Bose plundering, still!
I'd say go at least for 16 drivers per channel. Are they all created equal? The Bose speaker drivers I mean. If it were up to me I'd run impedance checks on all chosen drivers to see where you're at. If they are equal enough it could be a fun project.
Hand picked 32 drivers should get you there, That's a lot of Bose plundering, still!
Bose would be ~ 1ohm driver - here's my Series I 901 outdoors with no eq😀
- the red trace was with the rear of the 901 in typical distance to a back wall using
the outside wall of my house - note the midrange prominence
that popular little Vifa TC9FD should make a good 901 knockoff
- the red trace was with the rear of the 901 in typical distance to a back wall using
the outside wall of my house - note the midrange prominence
that popular little Vifa TC9FD should make a good 901 knockoff
yup, be ready to add eq, that 4" will need some trebble boost.
To me 4 x 4" is the area of an 8" (not enough).
The tc9 drivers, a 3" having a little more than half the area of a 4", can work, especially at $11 each.
If you want something that'll knock your socks off but ok limited to couch wide sweet spot width at 9', and ideally only sitting, you could focus them for excellent sound.
Norman
To me 4 x 4" is the area of an 8" (not enough).
The tc9 drivers, a 3" having a little more than half the area of a 4", can work, especially at $11 each.
If you want something that'll knock your socks off but ok limited to couch wide sweet spot width at 9', and ideally only sitting, you could focus them for excellent sound.
Norman
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[Blows dust off history book.] Once upon a time Bose 901 (series I and II) were a sealed box, er polyhedron 🙂 using an 8-ohm driver, the CTS 4C1077. Many Bose-os consider this the better model, especially with the cloth surrounds. Starting with series III-present, the Bose 901 mutated into a ported unit using a 1 ohm driver. Really two completely different speakers. I see no reason one could not use either in arrays, just you would need to put a whole bunch of the 1 ohms in series 🙂
I probably do have enough drivers on hand if I were to stoop so low as to cannibilize my working 901s. Hmmmm....
Unless they take me away first, I am going to build me a mini one and listen to how it sounds.
Freddi: thanks for the graph. The midrange SHOULD BE prominent ... sans EQ it is a midrange driver. But it tells us nothing about how a single driver would sound, or two dozen in an array 🙂 I would wager that [insert your favorite midrange or midwoofer driver here] would have a ragged graph under similar test circumstances.
I probably do have enough drivers on hand if I were to stoop so low as to cannibilize my working 901s. Hmmmm....
Unless they take me away first, I am going to build me a mini one and listen to how it sounds.
Freddi: thanks for the graph. The midrange SHOULD BE prominent ... sans EQ it is a midrange driver. But it tells us nothing about how a single driver would sound, or two dozen in an array 🙂 I would wager that [insert your favorite midrange or midwoofer driver here] would have a ragged graph under similar test circumstances.
Not be constrained by knowledge of the T/S specs for your Bose drivers, you might consider composite fence post covers available at typical home centers (Home Depot, Lowe's, etc.). Most available are 4" W x 4" D by 48" H dimensions. These covers are available made from a composite of recycled plastic milk cartoons (or similar) or plastic tubing. You can cut the tube length to mount the number of drivers you desire per module.
While the wall thickness of these fence post liners is typically 1/8", the tube is strong and could be supplemented by glued on strips of 1/4" thick hardwood if you wish additional strength.
I've designed MLTLs for 3" TangBand drivers with this material. I used hardwood caps to add some style to these designs.
While the wall thickness of these fence post liners is typically 1/8", the tube is strong and could be supplemented by glued on strips of 1/4" thick hardwood if you wish additional strength.
I've designed MLTLs for 3" TangBand drivers with this material. I used hardwood caps to add some style to these designs.
I used many of the pro PA model of the 2nd gen Bose (had to replace the darn foam surround periodically). I'd recommend 32 to 64 drivers a side if you like some dynamics...then you get some real body slam. I'm not sure whether a skinny line array can do that. The 3rd gen wired the drivers up the middle, and added a crossover on the outer dirvers...when you stacked them they formed a narrower vertical line array for the high frequencies using the middle drivers, then the drivers on the left and right sides kicked in for the lower mids. Lots of active EQ.
Re using the fence posts (other than having one's intelligence compred to one 🙄 )
I have eyed them when shopping for my hare-brained projects at the local home-improvement store (usu. Lowe's near me). But this was when I was considering TL's. For my 1st attempt, similar to what some other person did, is use a Sonotube or something even cheaper that I used for my "Polluto": a huge (and free!) cardboard tube that carpet comes on. No newer version of the Polluto has materialized yet, so why not try it for mounting the 901 drivers? I think 64 or even 32 is a bit optimistic at least at first; I haven't bought THAT many 901 pairs yet (or have I? I have 4 pair that I know of = 4 * 2 * 9 = 72 drivers + an unknown amount of disassembled units.) SO I could technically do the 32 per side pair. But I don't want to trash my working 901's.
I'm sure I can get a "hit" of what a line array may have to offer me -- if anything -- from just a little mini pair. As I described in Polluto thread, even two pair of a single cheap driver atop a glorified toilet paper roller (about 3' off floor) produces quite nice sound at "table top radio" listening volumes. I shall expect the same from my Line Arrays ... I want a 3-D performance of (say) light jazz; if I want same for Led Zeppelin at concert volume then I shall recur to more drivers. 🙂
I have eyed them when shopping for my hare-brained projects at the local home-improvement store (usu. Lowe's near me). But this was when I was considering TL's. For my 1st attempt, similar to what some other person did, is use a Sonotube or something even cheaper that I used for my "Polluto": a huge (and free!) cardboard tube that carpet comes on. No newer version of the Polluto has materialized yet, so why not try it for mounting the 901 drivers? I think 64 or even 32 is a bit optimistic at least at first; I haven't bought THAT many 901 pairs yet (or have I? I have 4 pair that I know of = 4 * 2 * 9 = 72 drivers + an unknown amount of disassembled units.) SO I could technically do the 32 per side pair. But I don't want to trash my working 901's.
I'm sure I can get a "hit" of what a line array may have to offer me -- if anything -- from just a little mini pair. As I described in Polluto thread, even two pair of a single cheap driver atop a glorified toilet paper roller (about 3' off floor) produces quite nice sound at "table top radio" listening volumes. I shall expect the same from my Line Arrays ... I want a 3-D performance of (say) light jazz; if I want same for Led Zeppelin at concert volume then I shall recur to more drivers. 🙂
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I built a 3 way line array a few years back
Twelve 5" woofers, Twenty 3" full range for mids and forty-eight 10mm dome tweeters. XO is at 350 Hz and 6KHz. The main thing I learned is to use full ranges with enough in the 100Hz to 10KHz band so subwoofers and super tweeters can be sliced in easily.
It has been 25 years since I've seen a 901 but it should do 100 to 10KHz without too much EQ. Always wondered why Bose didn't make a line array all those years ago...just kept building a backwards sweet 16.
Let us know how it goes--maybe start with a 9 stack since a standard pair has that many. Never know, if it works well with DSP it could be an option for all those Bose ohs out there.
Twelve 5" woofers, Twenty 3" full range for mids and forty-eight 10mm dome tweeters. XO is at 350 Hz and 6KHz. The main thing I learned is to use full ranges with enough in the 100Hz to 10KHz band so subwoofers and super tweeters can be sliced in easily.
It has been 25 years since I've seen a 901 but it should do 100 to 10KHz without too much EQ. Always wondered why Bose didn't make a line array all those years ago...just kept building a backwards sweet 16.
Let us know how it goes--maybe start with a 9 stack since a standard pair has that many. Never know, if it works well with DSP it could be an option for all those Bose ohs out there.
Might as well over-think this (thinking as an exerise is a novelty to me 
)
Other than tarnishing my reputation as a DIY audiophile ("How can you tarnish rust?" asks the peanut gallery.) I see no reason to not build the four drive module. This mainly is because it should fit on my standard sheet of coroplast: Well ok, there are some reasons to not to. My "unit" is 18x24". I have laid out drivers on a sheet, and 4 is just too big for the 18" side. But 5 drivers fit nicely on the 24" length. This would suggest (duh!) 5 per module. If so, the the front is 6" and indeed, make a triangle and 6" per side. Now to dredge for high school algebra and calculate volumes
Er, A = 1/2 * b * h; equilateral triangle so h = (er...) Pythagorean theorem so h^2 = sqrt ( 6^2 + 3^2) => h^2 = sqrt(36 + 9) = sqrt(47) => where's my damned calculator! => h = 6.86; A = (1/2)*6*6.86 = 20.57; V of a prism should = 20.57 * 24 = 493.6 in^3.
Now, off I go to Hornresp...
)Other than tarnishing my reputation as a DIY audiophile ("How can you tarnish rust?" asks the peanut gallery.) I see no reason to not build the four drive module. This mainly is because it should fit on my standard sheet of coroplast: Well ok, there are some reasons to not to. My "unit" is 18x24". I have laid out drivers on a sheet, and 4 is just too big for the 18" side. But 5 drivers fit nicely on the 24" length. This would suggest (duh!) 5 per module. If so, the the front is 6" and indeed, make a triangle and 6" per side. Now to dredge for high school algebra and calculate volumes
Er, A = 1/2 * b * h; equilateral triangle so h = (er...) Pythagorean theorem so h^2 = sqrt ( 6^2 + 3^2) => h^2 = sqrt(36 + 9) = sqrt(47) => where's my damned calculator! => h = 6.86; A = (1/2)*6*6.86 = 20.57; V of a prism should = 20.57 * 24 = 493.6 in^3.
Now, off I go to Hornresp...
Many line array threads here. Read 'em first.
The early Blose 901 CTS drivers are fairly horrid all things considered. Parts Express had some Vifa closeouts dirt cheap last year that make the old CTS drivers look sick.
IF you have working 901 boxes, sell them and buy decent drivers?
Work in sets of 3, series parallel the modules.
Ur plowing a field that's been cultivated many times, check to see what worked before starting a scratch re-invention of the wheel, imho.
_-_-bear
The early Blose 901 CTS drivers are fairly horrid all things considered. Parts Express had some Vifa closeouts dirt cheap last year that make the old CTS drivers look sick.
IF you have working 901 boxes, sell them and buy decent drivers?
Work in sets of 3, series parallel the modules.
Ur plowing a field that's been cultivated many times, check to see what worked before starting a scratch re-invention of the wheel, imho.
_-_-bear
Thank you for your insights. If you will so to speak "bear " with me, consider that a great part of DIY Is the joy of discovering something that is new to me, even though it be old news. A lot of our speaker designs we discuss here are fairly simple to build, yet or almost impossible to find anywhere unless you know another hobbyist that will demo one for you
Did you ever do this? I've got 18 Series III drivers, 18 cloth replacement surrounds to put on them (so no more refoaming after this time) and thinking about doing the same thing. These are 1 ohm hard plastic frame drivers with pretty big magnets and paper cones; 9 in series should make a nice easy-to-drive array. How will it sound? I dunno but I bet it plays loud!
With a little EQ will sound great. You need to go floor to ceiling for arrays to work well. At least 18 drivers at 4.5ohm series parallel.
Well, now I have 30 of them (all Series III and with production dates within 2 months of each other) and enough cloth replacement surrounds to do them all (and then some). 15 per side in series will make 15*0.9 = 13.5 ohm total impedance, perfect for my big old SET amps. In an 8' ceiling room that will just make the Jim Griffin criterion of woofer line length >/=70% of ceiling height.
Maybe two more just to be sure...
xrk971 is right. Lots of theoretical advantages to a line array but it has to meet basic assumptions.
Can anyone comment on building a dipole line array - that doesn't mute the rear radiation into a fence protector or sonotube?
Ben
Can anyone comment on building a dipole line array - that doesn't mute the rear radiation into a fence protector or sonotube?
Ben
Magz: yes, I did build the pair of Marimbas but only 9 (nine) drivers per side. They sound "good" but I have not yet done any more detailed measurements. What shall I compare them to? I have six Bose 901 (I, II) speakers I could use as "controls" 🙂
One thing I should test (oh God I am committing to something!) is to test the main reason for building the Marimba: Does the tube (resonator) actually give more efficiency? At what cost with peaks and nulls? Etc.
One thing I should test (oh God I am committing to something!) is to test the main reason for building the Marimba: Does the tube (resonator) actually give more efficiency? At what cost with peaks and nulls? Etc.
Thanks for the reply. Interesting LA/TL hybrid!
Mine will be a true LA when I get around to building it. I like the Series III drivers because I can make a very tube-friendly array with a simple series connection, and I also like the heft of them -the injection-molded frames are very rigid and the magnets are substantial.
I got a pair of them for free and sold the cabinets to someone else for what it cost to buy twelve more drivers online, so no net cost so far. That'll change going forward...
Mine will be a true LA when I get around to building it. I like the Series III drivers because I can make a very tube-friendly array with a simple series connection, and I also like the heft of them -the injection-molded frames are very rigid and the magnets are substantial.
I got a pair of them for free and sold the cabinets to someone else for what it cost to buy twelve more drivers online, so no net cost so far. That'll change going forward...
Not if your cabinets are castoff tubes. You could give each driver its own sealed box, er cyliinder ;-)
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