[FredT300B]

I know of several people, including me, who have built DIY line arrays for less than $1,000, and in many cases less than $500. These often fall into two categories:

For a bit under $1,000 you can build an arrays using very good quality drivers with a single ribbon tweeter (e.g. Eight 7" Dayton Reference woofers and a single Fountek or Aurum Cantus ribbon). This speaker will provide "high end" tonality, resolution, and clarity plus most of the improved sensitivity, soundstage, and dynamic capability of a more expensive line array. At one time Selah Audio offered a speaker called the Day-Tek that included eight 7" Dayton Reference woofers and a single Fountek ribbon. The ribbon was mounted to the side of the woofers on the baffle so one could later add more ribbons to form a tweeter array. A few years ago Jim Griffin exhibited his "Needles" array which included a large number of small (3"?) high quality midwoofers with a single Aurum Cantus ribbon in a sealed confuguration for use with a subwoofer. The Needles received much praise from other experienced speaker builders.

For less than $500 you can build an array using more affordable woofers with a single high sensitivity dome or horn tweeter. Some have built arrays costing about $100 using very inexpensive closeout woofers, like the NSB's, with an array of closeout dome tweeters like the 25 cent Onkyo's Parts Express was selling a few years back. Moving up a notch quite a few arrays have been built using better closeout drivers like the 4" Vifa's PE once sold for about $6 each plus a single higher quality tweeter. I previously posted a link to an example, and here it is again: http://www.lonesaguaro.com/speakers/array/array.htm

I've built a few of the under $500 type and have been pleased with the results. A few of the old farts of audio told me I wasted my money and should have built point source speakers instead using better quality drivers. As much as I hate to admit it, their point is well taken. I've also built $500 point source two-ways using better drivers, and I agree a $500 point source has better tonality and resolution than a $500 array. But while you can't overcome the limitations of the drivers you have selected, using them in an array versus a point source will give you the improved sensitivity, dynamics and soundstage of an array along with lower excursion-related distortion from the midwoofers. So it's just a tradeoff of one set of compromises versus another.

So who else has built a pair of budget line arrays, and what do you think of the sound? 

[Rick Craig]

I've designed a few budget arrays and am working on a new design. As things progress I'll post here in the circle. Like any project you need to establish your goals at the start and then test your drivers to see if they will perform well in your design.

The main problem I often see is that someone finds a good deal on a quantity of drivers and then asks what woofer or tweeter should they use with them. It seems to be difficult to find economical designs on the web that are correctly designed and implemented. Line arrays present a real challenge if you're working with a limited budget and little or no measurement / crossover software tools.

[zobsky]

I'll try and put together something later on on my budget arrays, .. but here are some random thoughts on building line arrays on the cheap for those of use who cannot, or chose not to, invest in a full blown array.

1. A critical issue when building arrays is the choice of tweeter - woofer crossover point . Jim Griffin's white paper goes into the details but basically, the larger the woofer (more / deeper bass), the earlier the roll-off when arrayed. Consequently, the tweeter must be crossed over lower. The problem is, tweeters that can be crossed over lower tend to be more expensive, .. and this really adds up in an array. Another issue of a lower crossover point is that the cost of passive crossover increases (if you use a passive crossover, that is).
Solutions (and their potential disadvantages):

2. Use a single fairly efficient tweeter (like Fred's budget arrays) . Disadvantages: a) different dispersion pattern b)the single tweeter will probably not project as far as the woofer array, and level adjustment may be needed for different rooms.

3. When arrayed, cheaper tweeters can be used somewhat lower than a single unit,.. as the power delivered to each driver is substantially less. Just don't take it too low. Another possibility would be to add a simple wave guide to the tweeter line to boost power handling and response.

4. Use a woofer with a rising response to counteract the array rolloff. That's the way I went in my project, and I still have a bit of a dip around 4KHz -5KHz before the tweeter line takes over but I consider it more like a" BBC dip of sorts", not really obnoxious. Disadvantage: Potentially, you could have a non uniform dispersion patterns , .. but I don't seem to find this an issue, or maybe I don't have golden ears.

5. Use a smaller driver. IMO, 4" woofers are the "sweet spot" for building budget arrays if you want to cross over to a line of tweeters, because they allow you to cross over fairly high (say 5KHz) without compromising on the array design. Also, budget drivers in this size tend to sound a bit better than their bigger brethen, and cabinets can be made somewhat smaller. Disadvantage: BASS !! - the array might sound plenty dynamic, but don't expect to shake the walls. Of course, a discretely placed sub or two should be able to fix this. Also, while they cost less, they are also smaller and you may need more of them to make up a specific array height.

6. For budget arrays, I feel that you can get a good percent of the benefits  (dynamics, wide sweet spot) by not going for a full blown 6 - 7 ft anti-WAF weapons, and instead keep the size down to a more domestically acceptable 3.5 - 5 ft. Make sure that the tweeter or tweeter line is inline with your ears in the sitting position. Disadvantage - if you stand up, you will probably notice the sound collapse.

On the treble side, if you chose to use an array of tweeters, be aware that the tweeter line maytend to roll off a bit on the top end depending on response characteristic of the individual driver and also the driver - driver spacing. There are a few different ways to address this IF you find this an issue. You may not run into this issuein certain  if for instance, your tweeters have an extended high freq. response and / or can be spaced extremely close (maybe trim the flanges), if you use a single tweeter to match the woofer line or if you use a line ribbon or planar, tweeters.

1. Passive tweeter compensation - haven't tried this, .. no comments
2. Electronic EQ - should work well, provide you don't overdo it and of course, own such a device
3. Use the treble control judiciously, if you have one - that's what I do - afterall all, my array's are budget :devices)
4. Add a supertweeter crossed over high, .. somewhere about 12 - 14KHz 1st order - I've done this with my pair of radioshack supertweeters. Unfortunately, their levels weren't matched so I grudgingy removed them and hooked up a pair of fountek JP2 ribbons that  I picked up locally for a good price.



Hope that helps.

[jamisons]

I understand that taller is generally better in line arrays, but another way to cut the budget is to cut the driver count and therefore the height. So what's the practical minimum height for an array that still more or less functions as it should but doesn't tower over my wife?

[Rick Craig]

I understand that taller is generally better in line arrays, but another way to cut the budget is to cut the driver count and therefore the height. So what's the practical minimum height for an array that still more or less functions as it should but doesn't tower over my wife?

In my experience a 45"-48" line starting towards the top of a 60" cabinet.

[zobsky]

I understand that taller is generally better in line arrays, but another way to cut the budget is to cut the driver count and therefore the height. So what's the practical minimum height for an array that still more or less functions as it should but doesn't tower over my wife?

Depends on the height of the wife. ..

Seriously, consider the points below:
1. Arrays have limited vertical dispersion, and as such, you'd want the array to extend at least a bit above ear level.
2. When seated, ear level is around 3 ft off the ground
3. With 1 and 2, in mind, 4 ft is probably a good starting point.
4. This isn't as important as the other points (or may not even be important), but here's another way of approaching the question. Depending on how you wire the drivers, you'd need  either 1,4,9,16,25 etc drivers to maintain the same NOMINAL impedance as the individual drivers. IF that'swhat you want to do. . Once you get past 9 drivers, .. the number of drivers increases significantly to maintain the same impedance. In that sense, 9 drivers is the sweet spot, assuming your drivers aren't too small. Assuming you use 4" to 5.25" drivers, your array line height would be around 36" to 47" tall, .. close to what we deduce in point 3.


Of course, you can always start the array a little bit off the ground, as Rick suggested to ensure that the listeners are in the sweet spot.
I cheated and used 12 8 ohm drivers wired 4P x 3S for a 6 ohm impedance line. 

[jamisons]

Height of the wife is 5'4" and she agreed to put up with my ~4'-6" tall electrostats. I know I'd probably be better off (for the money) going with a standard 2- or 3-way but I just can't resist the draw of more exotic/unique/unusual speakers! So yes, one reason for the electrostats. I'm not terribly pleased with the 'stats in my current room which is why I'm even bothering to ask, and a line array sounds like a nifty solution to my current gripe - the sweet spot is just too darned small and I rarely get to sit still for more than 5mins in it. The ability to wander around a bit and still hear a decent image is awfully tempting!

Reality is I won't make any changes any time soon, but it's all good fodder for thought. One of those "Someday..." thoughts...

[zobsky]

the sweet spot is just too darned small and I rarely get to sit still for more than 5mins in it.

Which is exactly why I got rid of my ancient maggies a few years ago. Of course the added dynamics, sensitivity and low distortion are a huge  added bonus, even on  more frugal arrays.

[FredT300B]

Here are some seriously bad budget dipole arrays. These are based on Zobsky's arrays. They have 14 Madisound $3 Foster extended range buyouts plus the cheapest Eminence compression driver with a $7 Dayton waveguide, all mounted on a 7' 4" by 16" piece of birch plywood. Total cost to build the pair was about $220. 

http://fredt300b.smugmug.com/gallery/3387487#189291245