I was thinking for a while about building a incredibly loud set of speakers using pro-audio type drivers in a line array.
I've started out by ordering 16 of these: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-010
I'm going to start out with 8 per side and if that isnt enough I'll move on to 16 per side.
For lows I was thinking 2 of these per side:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-085
I havent even really begun to consider different tweeters so suggestions are welcome.
What I'm going for in this project is sound quality comparable to higher end pro sound speakers(hopefully better) and of course high SplMax/efficiency.
Drivers should arrive next week, so enclosure building begins...
I've started out by ordering 16 of these: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-010
I'm going to start out with 8 per side and if that isnt enough I'll move on to 16 per side.
For lows I was thinking 2 of these per side:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-085
I havent even really begun to consider different tweeters so suggestions are welcome.
What I'm going for in this project is sound quality comparable to higher end pro sound speakers(hopefully better) and of course high SplMax/efficiency.
Drivers should arrive next week, so enclosure building begins...
Darn, I wish I could get something like those Dayton 5" over here ! I would have done the PA line array thing ages ago if I had access to driver like that !!!!
8 in series/parallel will give sensitivity of around 102dB at 4 ohm (quick brain calc) and around 400wrms power....... sweet
GO FOR IT !!!!
8 in series/parallel will give sensitivity of around 102dB at 4 ohm (quick brain calc) and around 400wrms power....... sweet
GO FOR IT !!!!
What I would do is build 4 lots of eight, then you can use either one or two sections per side depending on venue. Don't forget, unless they are "in-situ" (go 16 a side for sure) then someone has to move them !!!
Remember, that 16drivers only gives you 3dB gain over 8 speakers.
10 a side in a 3/2/2/3/ taper would work nice and be a workable size I think !
Remember, that 16drivers only gives you 3dB gain over 8 speakers.
10 a side in a 3/2/2/3/ taper would work nice and be a workable size I think !
We have to be a bit careful here. That second lot of 3dB is due to impedance halving hence amp doubling current. Trouble is , the 8 driver system would already be running at 4 ohms, so on most PA amps you could not run 2 sets parallel.
In fact , it would probably be best to run the second set off a separate amplifier.
In fact , it would probably be best to run the second set off a separate amplifier.
Yes I was thinking two amplifiers would be the better way to do things.
I was thinking I'd seperate the arrays into cabinets of 4 mid/woofers. So evetually I might have 4 cabs per side.
Anyone have thoughts on a tweeter like this:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=272-125
I was thinking I'd seperate the arrays into cabinets of 4 mid/woofers. So evetually I might have 4 cabs per side.
Anyone have thoughts on a tweeter like this:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=272-125
Bass,
I strongly urge you to read Dr. Griffin's work that he has shared online. You say "sound reinforcement", but in what kind of venue(s). Of greater importance than number of drivers is the length of the array and XO points. The real advantage to line arrays is in their range of nearfield operation and the resulting dispersion pattern. In the nearfield they decrease in SPL by -3db per doubling of distance vs -6db for regular speakers. With listening distance of 25-50ft (avg for a small venue) you're talking about a 10db advantage which is huge. The nearfield range is line length and frequency dependent. The projection distance and frequency range will tell you the line length required and number of drivers you need (driver spacing). Plan it well and you'll get great results. Purchasing a bunch of midrange drivers is the easiest part.
I strongly urge you to read Dr. Griffin's work that he has shared online. You say "sound reinforcement", but in what kind of venue(s). Of greater importance than number of drivers is the length of the array and XO points. The real advantage to line arrays is in their range of nearfield operation and the resulting dispersion pattern. In the nearfield they decrease in SPL by -3db per doubling of distance vs -6db for regular speakers. With listening distance of 25-50ft (avg for a small venue) you're talking about a 10db advantage which is huge. The nearfield range is line length and frequency dependent. The projection distance and frequency range will tell you the line length required and number of drivers you need (driver spacing). Plan it well and you'll get great results. Purchasing a bunch of midrange drivers is the easiest part.
No particular venue... this is just for my personal enjoyment. It will probably go in the basement of my shed most of the time... I have little use for a system like this(except to **** off neighbors and impress friends), just money to blow and curiousity.
You're very right John. Crossover frequencys will be crucial here. I think Bi or tri amping wouldnt be a bad idea using a digital crossover like the behringer dcx.
You're very right John. Crossover frequencys will be crucial here. I think Bi or tri amping wouldnt be a bad idea using a digital crossover like the behringer dcx.
A little update:
I built enclosures for the first 16 drivers. I must say when I started out and thought 8 per side might do it(and I'm sure it would if I were a reasonable person, I'm not), boy was I wrong!!!! 8 per side is pretty loud, but it's easily noticed that the ~8' line array projects the sound MUCH further. I've just set them up out in my shed for now and and have listened to them out in the yard. I'm sure the neighborhood loves it
I plan to order the next 16 drivers tomarrow and possibly tweeters also.
Does anyone have advice on the high frequency unit? I have very little experience with pro audio tweeters.
Horn-loaded compression drivers and bullet tweeters seem to be the norm, but being that sound quality is on my priority list the average pro-audio tweeter may not fit the bill
Driver spacing suggests a crossover at ~2khz
here's the tweeter I was thinking about earlier
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=272-125
I built enclosures for the first 16 drivers. I must say when I started out and thought 8 per side might do it(and I'm sure it would if I were a reasonable person, I'm not), boy was I wrong!!!! 8 per side is pretty loud, but it's easily noticed that the ~8' line array projects the sound MUCH further. I've just set them up out in my shed for now and and have listened to them out in the yard. I'm sure the neighborhood loves it
I plan to order the next 16 drivers tomarrow and possibly tweeters also.
Does anyone have advice on the high frequency unit? I have very little experience with pro audio tweeters.
Horn-loaded compression drivers and bullet tweeters seem to be the norm, but being that sound quality is on my priority list the average pro-audio tweeter may not fit the bill
Driver spacing suggests a crossover at ~2khz
here's the tweeter I was thinking about earlier
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=272-125
That Pyle tweet looks way to big for the frequencies it would be used at in a line(comb effects) and if you use it as a single unit in the center of a line the spl will only match the line at a certain distance. If you plan to set these up for a specific listening position then a single tweet is viable. Otherwise you might want to "borrow" a concept from Bill F and build a crossfiring peizo array or even a compression array for a low XO point.
I was definately thinking a single tweeter. Wouldnt the proper horn give me a decent match in dispersion???
I was thinking a horn quite like the one use for the mid unit in this project http://www.diyaudio.com/forums/showthread.php?s=&threadid=76396&perpage=10&pagenumber=2
Narrow vertical dispersion but wide horizontal dispersion(just like the line array)
I was thinking a horn quite like the one use for the mid unit in this project http://www.diyaudio.com/forums/showthread.php?s=&threadid=76396&perpage=10&pagenumber=2
Narrow vertical dispersion but wide horizontal dispersion(just like the line array)
You want a highly efficient tweeter like that, one that can outperform the line. Then just add an L-pad too it, so you can match its level with the line at that particular distance.
You should be able to audition that model locally. It's common in the car audio shops. I've used the smaller model Pyle bullet tweet in the center of several arrays. They're pretty harsh, but stuffing some small pieces of soft foam rubber down in the throat around the bullet, and that easy and reversible tweak really improved the sound. Bring a little soft open cell foam rubber and a small flat head screwdriver to stuff it in and remove it when you audition them. The store will be thankful for the idea, it works so well.
You should be able to audition that model locally. It's common in the car audio shops. I've used the smaller model Pyle bullet tweet in the center of several arrays. They're pretty harsh, but stuffing some small pieces of soft foam rubber down in the throat around the bullet, and that easy and reversible tweak really improved the sound. Bring a little soft open cell foam rubber and a small flat head screwdriver to stuff it in and remove it when you audition them. The store will be thankful for the idea, it works so well.
BassAwdyO said:
You can match the dispersion of a line with the proper horn, but the horn will still behave as a point source. A line array in near field operation only loses 3dB per doubling of distance; a point source will lose 6dB. If you plan to use the lines beyond the near field, you will lose the "magic" that the majority of us would build them for(keeping the sensitivity and power handling of multiple drivers), but you may level your single tweeter for the distance where the line transitions to 6dB and achieve acceptable sound for PA applications. What do you see as the primary use of these?
Primary use will be parties and small-medium performance venues.
The only reason a single tweeter seems attractive to me really is it's cheaper and it avoids any driver spacing issues. Building a line of tweeters seems quite expensive and finding a suitable tweeter is also not an easy task. A ribbon driver would be a good alternative, except they are also very expensive and most single units would probably have trouble keeping up with the mid- line
perhaps I should look into building my own ribbon driver? I have read about people having success in the alternative tech. forum.
Anyways The bass units will most likely be monopople as well. I considered horn loading, but I'd like to keep this system relatively compact and easy to transport.
The only reason a single tweeter seems attractive to me really is it's cheaper and it avoids any driver spacing issues. Building a line of tweeters seems quite expensive and finding a suitable tweeter is also not an easy task. A ribbon driver would be a good alternative, except they are also very expensive and most single units would probably have trouble keeping up with the mid- line
perhaps I should look into building my own ribbon driver? I have read about people having success in the alternative tech. forum.
Anyways The bass units will most likely be monopople as well. I considered horn loading, but I'd like to keep this system relatively compact and easy to transport.
An update.....
I bought 4 18" subwoofers for the project(eminence buyout hammer18). I know I said I didnt want extremely large enclosures and I'm sure anyone in pro audio would call me crazy(and many of you may do the same) but I built some 10cubic ft enclosures for them tuned to 30hz!!!!
I've decided against a single horn loaded tweeter.... Instead I'm thinking of using a dayton 3/4" neodymium tweeter line
Link- http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=275-035&CFID=6288971&CFTOKEN=65406144
That particular dayton driver offers spacing as low as 1 3/8 inches c-c(if modified and 1 1/2 unmodified). I dont know that 1/8" will do an aweful lot to reduce lobing issues, however I see no need to use 4 screws to mount a 3/4" tweeter so I'm thinking, heck I might as well modify it.
I was also thinking of using the same HF driver used in linkwitz's orion, but the sensitivity is quite low and power handling is no better than the dayton, plus the 2" driver size gives a larger c-c spacing and it is also more expensive!!!!
Link- http://www.madisound.com/cgi-bin/index.cgi?cart_id=5653076.18773&pid=102
I'm just not sure how long I want to make the tweeter line.... From a cost standpoint 32 drivers per side is feasible(which would give a line length of 44" for the tweeters).
The Midwoofer line is 83" long.... sooooo
Anyways here's a picture of two of the mid line prototypes(the one on the left is the one I've decided to go with) and two of the four subs!
I bought 4 18" subwoofers for the project(eminence buyout hammer18). I know I said I didnt want extremely large enclosures and I'm sure anyone in pro audio would call me crazy(and many of you may do the same) but I built some 10cubic ft enclosures for them tuned to 30hz!!!!
I've decided against a single horn loaded tweeter.... Instead I'm thinking of using a dayton 3/4" neodymium tweeter line
Link- http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=275-035&CFID=6288971&CFTOKEN=65406144
That particular dayton driver offers spacing as low as 1 3/8 inches c-c(if modified and 1 1/2 unmodified). I dont know that 1/8" will do an aweful lot to reduce lobing issues, however I see no need to use 4 screws to mount a 3/4" tweeter so I'm thinking, heck I might as well modify it.
I was also thinking of using the same HF driver used in linkwitz's orion, but the sensitivity is quite low and power handling is no better than the dayton, plus the 2" driver size gives a larger c-c spacing and it is also more expensive!!!!
Link- http://www.madisound.com/cgi-bin/index.cgi?cart_id=5653076.18773&pid=102
I'm just not sure how long I want to make the tweeter line.... From a cost standpoint 32 drivers per side is feasible(which would give a line length of 44" for the tweeters).
The Midwoofer line is 83" long.... sooooo
Anyways here's a picture of two of the mid line prototypes(the one on the left is the one I've decided to go with) and two of the four subs!
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