Line array assistance

A couple friends want me to make something quote '*******'n loud' for parties in the near future, for less than 150 bucks if possible. I was thinking a line array would probably do the job, just a bunch of cheap drivers right? Sound qualtity doesn't matter for these things (to them, not to me) but I'm curious if there is anything important I should take into account when building these arrays as I've never done one before, or if there would be a better solution to extreme louditude...

Also, I've found a number of drivers on blowout at parts express, notably a 4.5" vifa for 4 bucks, and an audax 6.5" for 10 at madisound, any benefits to size? We'll be fine in the bass department, I think every one of us has a pair of subs lyin around...

Anyways, thanks for any help offered

Edit: nice anti-swear script :)
 
A few more questions then, since I finally have a cheap driver..

1. It wouldn't appear to be necessary for a tweeter, at least not for what we're gonna be doing, am I looking at this right?

2. I remember a few people saying they coated these paricular drivers with watered-down glue or something to stiffen the cone up, what exactly was used and how does it help?

3. Any reason to bother with filters? Or would it be an unnecessary bother since I can just set the speaker setting to "small"

4. Sealed or open-baffle? Either way will be cake to do, I would think sealed would sound better personally, but then again we're just goin for spls here. Thanks for quick responses guys :)
 

thylantyr

Member
2001-02-19 10:38 pm
Mars
The NSB project is good but remember that it's just a midrange driver and you won't get any real low end bass out of them.
I would imagine for parties people want the 'boom boom'
{double meaning, rofl}...

The other issue is size. Are these speakers you want to build
have a permanent home ? you don't plan to move them alot ?

To keep cost down you can make a an array of 16 NSB
with a center horn so you have 8 NSB above the horn lense,
8 below. {actually, you can put that horn where you think it's
optimal for best sound}.

PE has lots of horns to choose from depending on the budget.

I don't know if not using a horn would be acceptable even
if they are not too picky on the sound quality.

If you want decent boom, model the NSB in software to
find the enclosure size/tuning you desire {ported box}.
I found that tuning them to 100hz is a nice compromise. I used
the enclosure volume indicated by the software to achieve a 6 to
9 db boost centered around 100hz. Nice natural 'boom box'
sound. You can add a subwoofer to capture the low if you want alot more bass.

The NSB is tricky to install, it has a frame issue to be dealt with.

Search google for "nsb line"
 

dastardly

Member
2004-08-20 5:20 pm
US
What about 16 NSBs with 12 dayton NEO tweeters?
OK. I modeled a crossover for this one in Speakerworkshop a while back just in case someday I have the money and motivation to try a line array. Of course, I haven't actually built anything, so my comments should be taken with a very large grain of salt. It may be crossed too low though, need to work on that part.

How many db down should a tweeter be at Fs?

Still $.49 per NSB and $4.10 per tweeter. And, ~99db/watt.
 
The NSB's are going to need a tweeter. Just use one of these per side with an Lpad to balance them with the array. A tweeter array isn't worth the trouble and expense for party speakers since you'd need alot more than 12 tweeters because everyone's ears need to be in the plane of the tweeter array sitting down or standing up. One of these per side will keep up with the array.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=272-115

A great tweak on the tweeter is to stuff 4-6 pencil eraser sized pieces of foam rubber down in the throat around the bullet. Tune to taste. It makes them worth far more than the $20/ea.

Although I love OB arrays, if loud is a primary concern, you'll want to go with a sealed box for power handling reasons and the subs you use need to go up to 100hz or so. You may want to build them to be hung from the ceiling for a cool look that can't get knocked over during a party.
 
Fortunately I'm not paying for this...I told my friend about the NSB's and he picked up 128 of them, just muttered something about 2 pair, which I assume means 32/loudspeaker...Anyways yeah that looks like the perfect tweeter John, I'll have to mention it.

Honestly I'm not really looking forward to mounting all these things...maybe I'll charge something for my services.

Shouldn't have to worry too much about bass, finishing the boxes for a pair of Avalanche 18's today, also got 2 Atlas 12's on the way, could always use them too i spose since I really don't need them right now...

Oh yeah, nice idea about the hanging speakers, realtor probably would charge us for it though...
 

dastardly

Member
2004-08-20 5:20 pm
US
johninCR said:
The NSB's are going to need a tweeter. Just use one of these per side with an Lpad to balance them with the array. A tweeter array isn't worth the trouble and expense for party speakers since you'd need alot more than 12 tweeters because everyone's ears need to be in the plane of the tweeter array sitting down or standing up. One of these per side will keep up with the array.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=272-115

A great tweak on the tweeter is to stuff 4-6 pencil eraser sized pieces of foam rubber down in the throat around the bullet. Tune to taste. It makes them worth far more than the $20/ea.

Although I love OB arrays, if loud is a primary concern, you'll want to go with a sealed box for power handling reasons and the subs you use need to go up to 100hz or so. You may want to build them to be hung from the ceiling for a cool look that can't get knocked over during a party.

Ooooo... that is a neat tweeter. Should the OP also be sure to pad the tweeter to a few db higher than the array level in order to compensate a bit for the difference in the way sound drops off for a point source vs an array?

As for using the NEOs, yeah the length of the tweeter array was giving me fits, since I could actually match db with only 6 tweeters, but that would give a 1ft array which pretty much wasn't useful. so, doubled it to 12 for 2ft, which could work in a theater room. If I ever do get around to trying this, maybe 18 would be better for a 3ft tweeter array. But, at that point you are talking $75 a side for a cheap tweeter, which might be better spent elsewhere. Oh well, all just speculation at this point.

Don
 
Dastardly,

If you go with a single tweeter then you have to use one that is more efficient than the array, then use the Lpad to balance it with the array to suit your listening position.

I find those tweeters super harsh out of the box, but a few small pieces of foam rubber really smooths them out and brings out the detail. For $20 I don't think you can beat it, 104db, good power handling, and nice detail.

With long arrays, you really need to use power tapering and with 32 I would consider it mandatory. Otherwise you will clearly hear the drivers on the ends due to their late arrival to your ears and it will grossly exaggerate the size of the audio image.
 
Your plan reminds me of recent discussions here;
http://www.caraudioforum.com/vbb3/showthread.php?t=212800

*I want loud music
*I want it cheap
*I want to use tons of NSB's

The design talks matured to this;
http://home.pacbell.net/lordpk/misc/Feandil.GIF

The center horn with tons of NSB's.

The final design optimized;
http://home.pacbell.net/lordpk/misc/Feandil-2.GIF

I think he chose 'B'.

Remove the extra NSB's and use some $15 7" Dayton woofers
to balance the design and offer better SQ in the midbass region,
a 3 way line array but there is no tweeter line so I call it a hybrid
array.

Email the owner to get some information on sound quality/performance.

I believe he used an Eminence compresson driver with a large
lense. A good bang for buck choice.
 
danvan said:
Yeah, i was kind of visualizing a pair of columns of nsb's with a hron in the center, so 16 total above and below, I'll suggest this and it'll probably be the final design. Is closing the boxes necessary? I just ask because it'll be a real pain to wire them up if its closed.

OB, sealed, ported, all offer sometning the 'party' <heh>

Wiring shouldn't factor in on your decision. You can install the wires inside the box and then close up the rear panel.

My design has PT2 planars, ported NSB's tuned to 100hz,
actually it will be 'variable tuning' because I'm adding doors
to the ports. Four NSB per chamber, each chamber has
a 6" dia. hole {the port}, 1 3/8" port length {thickness of the
wood}. I can fit my hand inside each chamber via the rear port
if I have to 'tweak' something.

There is no reason that your project can't offer really good sound
quality and high SPL by doing some careful planning and not
rushing the construction. I'm going the extra mile and I know
the NSB array will sound awesome because the build quality
has elements to make it sound better than just an empty box.
Plus, modding the NSB with $5 worth of material can improve
the sound quality alot.

I have a diary here of my progress;
http://www.caraudioforum.com/vbb3/showthread.php?t=210115

sneak peak, low quality pics.
http://www.caraudioforum.com/vbb3/showthread.php?t=216773

Try the bigger Eminence compression driver and choose a big
horn lense to improve the sound vs. a cheaper horn.

I bet you can give the 'store bought audiophile' speaker a run for the money if you pay attention to detail.

<wink> some of those Klipsch home speakers have horns,
cheap ones too. /lol


:devilr:
 
Danvan,

16 above and below is at least 12ft tall. Is this for outdoor parties?

Two columns of drivers will work if you roll off the high end of one of the columns at the baffle step point which would be a good thing, but you can't run the 2 columns full range.

If it's for outdoors, something easy to build and easily transportable would be to mount the array on a baffle that is inserted into an 8"-10" diameter PVC pipe cut in half. If you make it folding lengthwise, then it could be folded face-to-face for easy and safe transport. Ripping the PVC lengthwise would be the only tricky part and you'd need to be very carefull doing that part.

Regarding the wiring. If you build a box, make the rear panel removeable or put it on last. The wiring is a pain, so solder wires onto each driver before even mounting it to the baffle.
 
I was thinking like this John, and I guess this is what we're gonne do (I have minimal say in what actually gets done) though I'm still trying to get them to do ported.

m m
m m
m m
m m
m m
m m
m m
m m
h
m m
m m
m m
m m
m m
m m
m m
m m

Not really sure what the rush is to make them...everybody's leaving Ames now that classes are over *so parties would be marginal at best) , but w/e. If I can get them to help I'll coat the cones with laquer, thats just a helluva lot of drivers to do by myself. 3-4 coats should be enough right? Nice looking cabinets thylantyr! I'm curious though, how are you going to hide the not-so-pretty frames on the NSB's?
 
As far as the tweeter goes, I have the Eminence APT50 compression tweeters modified by Adire for their HE kits and the Pyle sounds just as good after tweeking but is much cheaper. Also the Pyle will have better dispersion for indoor party use unless it's a very large room because the typical rectangular horn lenses have limited vertical dispersion.

Just a coil at the low end of the baffle step point may do the trick to avoid cancellation problems from the use of 2 columns in your array.

Ported or sealed will really depend on the subs you have available. Neither will get you hard hitting bass in critical 70-100hz range needed for party music, so you are going to have to rely on the subs for that range anyway. That makes it a matter of integrateing the subs output with the mains and it will probably be easiest with sealed mains unless you have subs with steep XO slopes.