Dayton Line Arrays...

Questions:

Why the full range drivers? They have an xmax of 1.5mm

DAYTON PT2B-8 PLANAR TWEETER (partsexpress 275-085)- 4 or 6 in each array
DAYTON PA130-8 5" FULL RANGE P.A. DRIVER (PE 295-010)- 9 or 12 in each array

Those PT2s should cost under $25 if you order bulk vs. $32. The PT2 performs better in
big arrays, approx 8 - 12 unit per array using low impedance wiring to boost sensitivity.
A single PT2 isn't a great tweeter but when you use alot of them, distortion is much lower
than the single PT2 at the same SPL level. More is better when it comes to line arrays.

The tweeter is the bottleneck so figure out what you want by analyzing the tweeter
performance and try to get a decent amp to run a lower impedance. You can cheat
the amplifier impedance rating. If you have a quality power amp rated for 4 ohms/ch,
it can probably work well with 1 ohm/ch tweeter load only. For midranges, you can
cheat but not as much. If your quality amp is rated for 4 ohms/ch, you can run midranges only with as low a 2 ohms/ch. This will help you optimize performance.

Look at different tweeter setups to find what you like;

Four PT2 wired for 8 ohms = 94dB sensitivity.
Four PT2 wired for 2 ohms = 100dB sensitivity.
Six PT2 wired for 5.3 ohms = 95.8dB sensitivity.
Six PT2 wired for 1.3 ohms = 101.9 dB sensitivity.
Eight PT2 wired for 4 ohms = 97dB sensitivity.
Eight PT2 wred for 1 ohm = 103dB sensitivity.

Assuming no power tapering, less tweeters = smaller sound stage. Less tweeters
used = more distortion at higher SPL.

Eight PT2 wired for 1 ohm is pretty sweet. 103dB sensitivity calculated. Suppose
you can make this work, then you are looking at a 65" tweeter line. I'd probably
choose 12 Dayton mids to mate with this because that is about a 69" line with
5.75" CTC spacing. This is about 100dB sensitivity just by using 12 mids. Good wiring options are 6 ohms [102dB] or 2.6 ohms [105dB]. Even with a comfortable 6 ohm
wiring option, you can get about 102dB sensitivity which fits well with your 103dB tweeter
line. You get the idea.

If you want to crossover to subs in the 50hz range, you can probably run your
subs higher, perhaps up to 80hz to integrate the sound to the line arrays. You can
dial this in later. But for now, you may want to model the Dayton midrange array
in a ported box to see what the graph looks like to extend the bass performance lower.

If you can afford a DCX2496, that can help you in many ways. You can learn more
about audio as it's a great tool and it has alot of features to play with and really good
crossovers, EQ, delay, etc. Don't be afraid to use XLR gear. You can make your own
XLR to RCA cable to interface with your amplifiers that use RCA input. You can make
a special cable to reduce XLR output by -6dB to optimize the noise. Later, you
can get a better source to drive the DCX input if your source is RCA output with a low
voltage - it will work, but not optimal. The PT2 array really benefits from the LR 8th
order crossover found in the DCX. You can take the crossover down to 1.7khz and
get much better sound vs. 3.5khz or so using 2nd order slopes. Try to get at least
LR 4th order for the line array project.

* Use your current active crossover for now as you can always upgrade gear if you think
you need it.

* You should contact PE and see what kind of volume discount is available
on the drivers.

* Another idea: Get the 12 mids right now to make your 70" midrange line.
Design your line array box to support ten PT2 which is a 65" line. Chamber the box
so the tweeter airspace is isolated from the midrange airspace, for two reasons.
You may have air leakage into the PT2 diaphram, it has been known to happen before.
You can install six tweeters per tower right now, but there is room for four more later
when you get more cash. You can cover the empty tweeter slots with a piece of wood so it won't
look to weird.

* You can do clever wiring, lower impedance and higher impedance since your are using
an active setup, this makes your array more user friendly with amplifiers.

* You can make a prototype test box using cheap wood to test a ported design, then
plug the port to see if you like the sealed box sound.

* If ported, model the midranges in different chamber designs as it will
give you some options for different porting methods. For instance, my budget
array worked nice with four chambers, four mids per chamber and a 6" hole in the back as the port, one hole per chamber. Plus, the wood to create the shelf
for each chamber also serves to brace the box to make it dead.

I don't see any reason why this project can't have great sound, just pay
attention to the details when you make your cabinets. Make sure you brace
well, install polyfill properly, make sure the mids are sealed well when you
install them, perhaps buy some PE rope caulk to put around the mids to
make an air tight seal. All the these small details yields higher performance.

DAYTON PA130-8 5" FULL RANGE P.A. DRIVER (PE 295-010)

Some generic ideas for a ported box design using 12 mids.

#1 - Four mids per chamber, three chambers. 1 cu. ft. per chamber tuned anywhere
from 70hz - 90hz, 4" rear port.

#2 - Four mids per chamber, three chambers. 1.5 cu. ft. per chamber tuned anywhere
from 65hz - 75hz, 4" rear port.

The higher tune has a peak in upper midbass for more umph in sound. You can plug
the 4" ports to get sealed box sound.

You have to figure out the cabinet size and what you want to do first.

The dampener won't be as effective as you may think for a wooden speaker box
as proper wood construction rules. That stuff is good for metal surfaces, that's
why it's used in car audio installs. I'd rather sell that dampener to reclaim more money
for the project. Proper bracing is the key to success. Loose polyfill if you do a ported box
and don't block the port. If sealed box, you can make it more dense. The tweeter chamber
can be very small, just deep enough to drop in the tweeter in it's place. Integrating a subwoofer into the line array can work but there are some issues you need to know about.

My budget array is about 200 pounds per tower. 3/4" oak plywood box with seperate
chambers and 12" x 12" 5/8" MDF panels on each wall in the chambers to add mass,
to make the box dead. Then I cross braced the left and right walls with a 1" dowel
to make it more dead. hehe... Even so, the tower is very heavy. Imagine if you add
more weight by integrating a subwoofer. The next issue is.. what if you want a better
subwoofer in the future, what will you do? Build more? What if the two subwoofers
have performance issues on the spot you install the array at? What then? If you keep
the subwoofers a seperate box, you can move them around the house for best sound,
you can sell them if you want to upgrade in the future. You can make the subs a seperate
box and just place the line array on top of it. hehe

I can probably see you upgrade the subwoofer as time passes. But a good
line array can last you a long time if you pay attention to some details right now
and don't skimp. If you use the PT2, a big array of them is very sweet. If you
implement the dual impedance switch idea, it makes your array more user friendly just in case you want to push it to higher levels with some monster proamps,
those amps will hang with a lower impedance. The mids you chose should do the job well and you can do the impedance switch on them too. There are ways to
make the line array more future proof and it's small details. If you execute this project well, you should have a killer array that will have some amazing SQL potential. Nothing in the store would offer this type of SQL for under $20k.

Don't assume the project can't work awesome. Pay attention to details, take your time, and it can punish people.

You can PM or email if you want to talk about this more.

Goober,

Did you ever build this line array?

Marlboro

I have been toying with this idea aswell, I wanted to build the TMWW towers from the htguide forums.... but I keep looking at other peoples line arrays and want to build it more and more.... but like goober, I don't want to spend an arm and a leg for a "test". Besides.... I have no idea on how to contruct a crossover to match my center and make the arrays sound decent.

I thought of a design of 6 tweeters (not sure on planar or dome), 6 4"- 5" mids and 1 12"

Thy, care to shed more light on your arrays?

Random;

* Line array work best if they are big. No such thing as a small line array - harr harr

* It's a big project, lots of drivers an the costs add up. Given the $$$ scope of the project
you might as well implement an electronic or digital crossover to ease your pain.

* The line array will give you a big sound stage, higher SPL potential, low distortion.
If you don't need these three traits, don't bother.

Here's a picture of mine:

http://pub48.bravenet.com/photocente...31&album=48032

Here's a description:

I don't believe in building other people's work, but in designing my own, and then building it myself.


I chose several design goals:

1. use a 3 way, not a 2 way

2. NOT break up as much of the critical human hearing frequencies between 300hz and 3000hz as possible with the effects of a crossover

3. Use electrical crossovers

4. Separate the midranges in the array completely from each other and use a 4 lb/cu ft fiberglass stuffing, in a long tube to reduce the backwave sound radiation to almost nothing through absorption, and to prevent any interaction with any other speakers in that backwave.

5. Keep the cost for all including electronics of this down below $1300.

I was successful in all design parameters except that I couldn't get all the way to 3000hz. I will probably switch to a digital electronic crossover in the summertime.

I followed Jim Griffin's white paper to the letter, as well as had several communications with Jim about it.

1. 2 12 inch goldsound 15 mm xmax woofers

2. 34 Sammi 3 inch 3.3 mm xmax mid woofs, 5 inch c-to-c, requiring no more than 2750 hz cross. High quality South Korean speaker with a copper voice coil, paper fiber composite cone, similar to current HiVi models.

3. 60 Dayton ND20FA tweeters with cut flanges to .9 inch c-to-c to limit comb filter distortion to above 15khz(and inaudible in my environment)

4. Crossover is Rane AC23 electronic at 165, and 2600, 24 db/octave L-R, with analog electronic time delay.

5. Separate 350 w/ch amp for woofers, 150 w/ch amp for mid ranges, 60 w/ch amp for Tweeters, Kenwood B-1 Basic Pre-amp. prefer vintage 80's equipment(in this case Linear Tech for the woofers, Kenwood Km-106 for the mids, and Sherwood for the tweeters)

Each midrange is enclosed in its completely separated(3/4 inch of open air) 23.5 inch x 4.0 inch PVC tube stuffed with 4 lb/cu ft weight Pillow fill sheet covering Fiberglass insulation(from research by Vance Dickason and Rod Elliot.)

Woofers are currently in a too-small boxes which only allow a flat extension to about 39hz, but will soon move to a set of 6.1 cu ft boxes allowing a lower extension to about 23hz.