Stupid Cheap Line Array

WRSugar:

For what it's worth, my best success has been a 1st order Butterworth at 500 and 7000 (to the Apex Jrs). The report shows nearly flat output and very flat phase. The tweeters are probably getting a bit too much low frequency, so I've put in a tweeter protector -15 dB below 700. Then again, you're not using the tweeters, are you? I'm going to try two-way with the 525's and 3's alone when I get home and let you know what I come up with.

Greg
 
Greg,
Now to find a 12" woofer that will go low and be loud enough to keep up with the other lines. I'm not going with a line array of woofers, although it would be cool to see--I think I'll call my 3-ways IRS V but not for Infinity Reference System... more like Idiot Recycling Speakers revision 5. :rolleyes:

I really like the 3.5 way, especially considering the bass boost will be applied actively but the 0.5 way passively with only a coil. No major passive x-over issues there. Then again, if I'm going to have 10.5" wide worth of woofers, why not just get some of those MCM 8 or 10" woofers with much more excursion, a lower natural frequency, and overall cheaper? This way I won't have to cut 15-20dB off of the meat of the curve, maybe 5-10.

Greg

That's the direction I'll be heading with my Stupid Cheap Line array :D

The 10" PE buyout I got 12 off ebay for $50 shipped, and 4 from PE when I wanted to test em. So I have 8 10" for each array, 16 sony neos per side,
and left to acquire is upper midrange and treble :D

The waiting game sucks :D
 
Kahooli,

16 Sony Neos per side? I'm running 12 of them and they work well for 75 to 500 Hz bass response, they are not good for mids as the main reason I'm going with the NS3s either 3S/7P for 7 ohms or 4S/5P for 13 ohms depending on how well they mesh with the Apex Jrs at 6KHz and the Neos at 400Hz.

Greg,
I find you using such a shallow 1st order filter to the tweeter line at 7 KHz very interesting, is your tweeter protection basically a 12dB filter running at 5KHz then a cap after it? If that works well, it will be one less point of problems to deal with so care to elaborate?

For sub bass I'm going to use the "Kraken 1x12" or a 18Hz tuned tapped horn 5.5 feet H, 14" W and 24" D crossed at around 70Hz. The Sony Neos can handle that without issue and the horns should preserve the dynamics of the arrays (in theory)

9 more days and I get to have that new driver NS3 smell :hohoho:
 
Kahooli,

16 Sony Neos per side? I'm running 12 of them and they work well for 75 to 500 Hz bass response, they are not good for mids as the main reason I'm going with the NS3s either 3S/7P for 7 ohms or 4S/5P for 13 ohms depending on how well they mesh with the Apex Jrs at 6KHz and the Neos at 400Hz.

The 10s will provide relatively flat capability down past fs in room. 16 x ~91db woofers with fs of 33 is quite capable, especially with the directive gain of the array.
So appx ranges are fs-80 Sammi 10s
80- (800-1.6k) sony neo
(800-1.6k) - (??) something
(??-??) something else.

I've set a strict per-line limit on my budget, so far I'm at
$.67*32 +$69 = 21.44 + 69 = $90.44 for both, or $45.22 each.
I'm either going with an apex tweeter line or wait for some new product to arrive.
I still need something to bridge the gap though.

Sorry for threadjack.
 
Kahooli,

16 Sony Neos per side? I'm running 12 of them and they work well for 75 to 500 Hz bass response, they are not good for mids as the main reason I'm going with the NS3s either 3S/7P for 7 ohms or 4S/5P for 13 ohms depending on how well they mesh with the Apex Jrs at 6KHz and the Neos at 400Hz.

Greg,
I find you using such a shallow 1st order filter to the tweeter line at 7 KHz very interesting, is your tweeter protection basically a 12dB filter running at 5KHz then a cap after it? If that works well, it will be one less point of problems to deal with so care to elaborate?

For sub bass I'm going to use the "Kraken 1x12" or a 18Hz tuned tapped horn 5.5 feet H, 14" W and 24" D crossed at around 70Hz. The Sony Neos can handle that without issue and the horns should preserve the dynamics of the arrays (in theory)

9 more days and I get to have that new driver NS3 smell :hohoho:
Yeah, the Aura NS525s have the same problem. I was going to use them initially over the NS6 because I figured they had better upper midrange, but it's garbage. The NS3's and NS6's midrange is superior.

18, I'm not sure how much I can elaborate on my filter to help you out... I'm running this all through the Behringer. So yes and no, I'm running a 12dB/dec second filter on the tweeter for LF protection. But the phase issues doing this don't pop up for me crossing actively, and phase is the whole purpose of the BU1 filter to begin with. And I can tell you for my system it works like gangbusters over the BU3, or LR2/4/6. I haven't tried Bessels yet, but I'm VERY happy about how tight an image I'm getting from Nina Simone's vocals. I've heard better, but never from $8.50 worth of drivers ($5 of which is that Sinar Baja (SB Acoustics) polydome (yes, it's listed as fabric on Madisound, that's BS).

So yeah, long way of saying I've got an extra LR2 at I think 700Hz (if you place it at 5kHz you'll severely effect the Butterworth rolloff). I wanted to make sure that it wouldn't effect anything about 2000 Hz. Keep in mind that the sub 1kHz output on those tweeters will be -45 to -60 dB (going by memory), but since that's a good part the acoustic rolloff, not electrical. Probably not a good thing, but as loud as I've pushed my single driver 3-way system, I've yet to get scratchiness from the 1" domes.

I guess that I got pretty good imaging going with an LR2@7kHz/inverted tweet as well, but not as nice as the B1.

Greg
 
More on-topic threadjacking.
the NS3's may work well by themselves down past 200Hz, but I wouldn't want to use them with a 5.25 on the bottom. I'd rather use something smaller to have the array reach higher. The madisound distortion plot shows a peak from 5-7k. How high are most people running the ns3?
---
Are there any inexpensive 2s floating around the net? Are those gento 2s on ebay worth a damn?
 
More on-topic threadjacking.
the NS3's may work well by themselves down past 200Hz, but I wouldn't want to use them with a 5.25 on the bottom. I'd rather use something smaller to have the array reach higher. The madisound distortion plot shows a peak from 5-7k. How high are most people running the ns3?
---
Are there any inexpensive 2s floating around the net? Are those gento 2s on ebay worth a damn?

Not threadjacking at all.

I'm running the NS3's down to 500 BU1. 525's on the bottom are ok with subs or if you're running active and taking advantage of the super high sensitivity in order to cut down the mids (make the low bass pop out). OPC's 3" full range array got flat to 20, so I'd imagine the 525's would do it easier.

That said, I'd say one of two things; use the 5's passively if you have a single subwoofer channel with the NS3's on top (or NS3 mids and apexjr tweets on top). OR, and I think this is kinda interesting, if your amp has 2 channel subwoofer outs, then set the sub's cutoff for as high as you can go with the 10's or 12"s (maybe 250Hz if you can), and cut NS3's off at that point at the same rolloff. The "subs" being directional at those frequencies is irrelevant if you place them near the front channels. I believe that most receivers have an LR2 cutoff to sub outs. If you ran the NS3's full range above, they'd be ok on the top, but I prefer them with a tweeter.

As far as I know, there's no real decent 2" driver in the price range. I haven't seen many on ebay though, so I can't discount what you were looking at. I would think that a decent 2" mated to 6" drivers (maybe the Aura NS6) would be ideal, but I agree with 18; there really isn't a 5" driver with decent midrange, and no cheap tweeter that can run low enough to keep the 5's and 6's from combing. A 2" may be a solution, so long as it can go low enough.

Greg
 
Looked at the distortion graphs on the NS3s

The THD is well below 1% from 400Hz to 6,300Hz and my tweeters are recommended a crossover at 6,000 Hz second order. Figure a LR2 at 6KHz would be a decent compromise to stay out of the distortion band from both drivers. 21 NS3s should give me very, very low distortion in the first place so more of an OCD thing on my part.

They are a fun project to learn about vertical dispersion limiting in a metal walled garage--so far, so good. By the time 42 NS3s hit one watt each, I don't think I'll be concerned about half a percent of distortion--the 105+ dB levels 4 meters away would probably run me out of there before hand. :cheers:
 
I was intending to do everything active during the design and testing. I have 9 channels of spare amps lying around, and a dsp capable of doing anything I program it to do.
Why not use it? :D
=======
Like I said, just need something to bridge the gap from the 5.25 sony line to some sort of tweeter array, likely being the apex jr tweeters.

The ns3 could work. I doubt they'll run out of them anytime soon so I'll play the waiting game for a while.
 
Kahooli,

16 Sony 5" woofers, NS3 mids and Apex Jr. tweeters--that sounds very familiar. ;) I don't have 9 channels of amplification laying around and no dsp, but I do have a RTA with microphone, a laptop to play test tones, multi-meters, o-scope and skills with a Roto-Zip.

Figure by the first week in January, (NS3s are a Christmas gift) I should have new bezels cut, the 3 inchers will be broken in and I should be able to get meaningful results out of them. My main curiosity is how efficient each line is compared to each other. 12 Sony woofers, (7 ohms) 21 NS3s (7 or 13 ohms) and 48 Apex Jrs (4.5 ohms) = ???

I'll try to get them at 97dB at 2.83V +/- 1dB of sensitivity from each line. That is the goal, I'll only know when the test tones play and my meter gives me the results. On paper, the Sonys should be 96dB, the NS3s at 98.5dB and the Apex Jrs when wired to 4.5 ohms about 96 to 97dB.

The strong bass boost arrays seem to throw out there might get the Sonys fairly even with the NS3s at 400Hz--I'll test and find out.
 
Measurements are the key to any success. You can simulate all day long but imo you have to measure at some point :D

That's something I learned about 2 months after leaving uni.
"wait, why doesn't it work! It simulated SO WELL"
-failed attempt at a broadband 600W UHF amplifier.
=========

I hope the 2x8 10" woofer lines integrate well enough. I plan to make this a single baffle WWMT lines, floor to ceiling, slightly tilted forward to reach seated positions at the center line, and a very slight power taper. Not sure if I want to do a U-frame or seal it up and play with Q

Gain structuring is going to be a nasty hurdle with so many different combinations of drivers, sensitivities, array directivity, and presented impedance.

oi-i-weh!
 
Measurements are the key to any success. You can simulate all day long but imo you have to measure at some point :D

Gain structuring is going to be a nasty hurdle with so many different combinations of drivers, sensitivities, array directivity, and presented impedance.

oi-i-weh!

I'm with you there,

It will be rather simple to measure--just a pain in the butt to wire them! At least the tweeter lines and woofer lines are already wired, the mids should not be too tough...just hope they are close with the initial configuration.

That's what makes this fun...right? When I grow up, I'm going to move to a place called theory--everything works there!
 
I hope the 2x8 10" woofer lines integrate well enough. I plan to make this a single baffle WWMT lines, floor to ceiling, slightly tilted forward to reach seated positions at the center line, and a very slight power taper. Not sure if I want to do a U-frame or seal it up and play with Q
oi-i-weh!

So two rows of 10" woofers, then mid, then tweet? Sounds like bass city.

So here's something different. I assume you've all seen the Kuze line array project on P-E. What about taking a hint from that for cabinets? I happen to have access to very large schedule 80 (thick walled) PVC pipe, so I'm tempted to play. I'm worried about standing waves though, even if I divide the pipe into 4 driver (or 2 or individual) chambers. What could be done is to modify the pipe by cutting it and gluing together segments as in A or C (B&W style), or just adding something like L channel or a piece of triangular molding at the back. I have NO IDEA how to design cabinets to reduce standing waves other than irregularity kinda generally being helpful.

I thought about the divider shelves, and I think that grooves in the inside of the PVC can be made with a small rotozip or dremel router attachment and small shelves can be cut from thin plywood (or something less resonant). Maybe throw a few pounds of epoxy in there... Baffles made out of MDF.

I'd bet that a little sandpaper would make piano black veneer really easy to apply to PVC. BTW, I'm sorry about B, I forgot to add the little arrow into Draftsight before JPEGing and deleting the dwg, so I painted it in after. You get the idea.

Greg
 

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Oh that's right, 4-way.

To be honest, I don't entirely see why you want to make things this complex. The table that I made up to calculate combing of drivers based on C-C shows that 10" woofers won't comb until 1351 Hz. That means that even by the more stringent lambda/2 qualification, they're good to the same frequency that I'm using now for the 525s, just not with a 1st order filter. The 525's that I have are definitely only good to about 800 anyway, and actually, despite my success with the Aura 3's running to 7k, they're going to comb again between 4-8k, since 4kHz lambda is in the 3" range. I may end up going back to a 5kHz LR4-6 for the tweeter, depending on how audible the combing is. The whole point of the tweeter was to quell that.

Greg
 
Oh that's right, 4-way.

To be honest, I don't entirely see why you want to make things this complex. The table that I made up to calculate combing of drivers based on C-C shows that 10" woofers won't comb until 1351 Hz. That means that even by the more stringent lambda/2 qualification, they're good to the same frequency that I'm using now for the 525s, just not with a 1st order filter. The 525's that I have are definitely only good to about 800 anyway, and actually, despite my success with the Aura 3's running to 7k, they're going to comb again between 4-8k, since 4kHz lambda is in the 3" range. I may end up going back to a 5kHz LR4-6 for the tweeter, depending on how audible the combing is. The whole point of the tweeter was to quell that.

Greg

The distortion performance of these 10's degrades rapidly after 400-500Hz, depending on the sample. There's a quality control issure in the motor. Some are good past 1200, most arent. that's why I'm using them as essentially a subwoofer line. Low sensitivity samples will be put nearest the ceiling and floor as a form of natural power tapering, there wont be any actual electrical tapering.

I'm limiting each driver to its most suitable range. I have no faith that the sony array can reach as deeply as I want without a separate sub. I want as close to Full range sound from a stereo pair as possible. Keeping excursion to a minimum will help the distortion figures at any output level. Why make a 5.25 do what a 10 can do better? Why make a 10 do what a 5.25 can do better? and sound better doing it? Complexity isn't a bad thing if it's done right.

I have a lot of ambition.
 
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You mentioned the NS3s sounded good crossing at 7KHz BU1,

They sounded less clean at LR2 at 6KHz although combing would have increased going to 7KHz? It all depends on your tweeters at this point, my Apex Jrs. run 4,300 LR3 at this point and that is too low so I need to push them up. It does fit the C to C distance of the NS3s as far as beaming is concerned, it just does not have the output to blend.

Audax shows a BU2 schematic for their tweeter at 6KHz, testing on an array with 49 of those tweeters show 5K to be down 6dB compared to 6K so I'll error on the side of output. The half octave of beaming will just have to be one of those things--beaming VS smooth output. My Infinity Overture MTM speakers beam from 2,000 to 3,000 Hz but their output is even and it does not bother me, figure the same will hold true with the garage arrays from 4,300 to 6,000 Hz IF I don't get any spikes/dips in output volume.

I break up standing waves in my array box very easily, the back panel has angled wood scraps, the huge amount of wiring, crossover filter boards, fiber fill and braces make it a maze. Not pretty but throwing in braces at all sorts of odd angles really helps that issue.

PVC pipe is pretty cool, it would have the standing waves of....well, a pipe organ. ;) I thought about PVC but figured it would be a huge pipe to get the bezel attached so scraped the idea. A pipe with just NS3 mids would be a great option if running bass bins. Since cutting the pipe would be a royal pain in the butt, I'd use that really stiff plastic foam and cut discs to slide into the pipe. Compress it a bit, throw some RTV in for a seal and run it up and down the pipe. The foam will stop standing waves, absorb vibration and naturally seal the pipe without requiring cutting the pipe into pieces. If your worried about standing waves inside each enclosure, use bits and pieces of the foam to glue to the back of the pipe to keep it uneven. Put that smelly RTV/foam PVC pipe out in the garage for a week to let it cure.

Another option is that plastic square cross section stuff called fence post. You can get it in various sizes and it would be much easier than pipe to make small enclosures. Get the 5 inch version, cut away a slot 3.5 inches wide down the front so you have 0.75 on each side to attach the bezel? Use some 1/4" plywood to stiffen the back of the enclosure, use the plastic foam blocks to divide it and fill with fiber fill.

Although I'm using tweeter lines, it would be interesting to see how high up the NS3s go smoothly with decent sound--a fence post column of them with a super tweeter on top at 10K or so along with active bass for 300Hz and below would be a much simpler build. Not perfect but much easier in case my buddies just have to have line arrays in their garages also.
 
I've got 8 of the 525 with a single APT200 playing nice down to 50Hz, but the cabinet is 4.2 cf ported. I'm calling that one good enough. - Next up is a tall line of NS3 with some EQ bump up high, and XO to a sub at 150.

I'm about to abandon it all and get on with proper drivers, though. I'd rather be using the things than guessing about how to make them sing. Up next are a line of Alpha 6 or Celestion with NEO 8 or PT2.
 
Opened my box of 50 NS3s today,

Roamed over to the garage and wired three of them in parallel sitting in a small cardboard box. Very clear sound but three of them have that full range shout of rising response. The array effect will cut that down when piled 21 high and cross to the tweeter line at 6KHz.

Adason crossed his to subs at 160Hz and he liked the warm sound of them, I would never use them that low as a PA speaker though--maybe 300Hz with a 4th order electronic crossover.

Might have the box of NS3 paper cones all broken in by next week--then hit or miss on warm weather to play the Roto-Zip hole cutting game. I'll need the Roto to rear mount them on 1/2" ply and cut the hole at an angle for a bevel. Finish sand the bevel to make a mild round over to prevent diffraction. Use more 1/2" ply to make a small, stuffed sealed box to protect them from the woofer line.

I can then test them and hope to get close as I attempt to bring 3 lines together then try to get them to play nice. :scratch1: Some idiot should try to get a multi-way line array to work completely passive (no EQ)--hope it is me!

Let me know if you are having any issues with the NS3s, I'm playing with my pile of them and might have a solution, or at least an idea.
 
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EQ is your best friend on the NS3's. I mean, it's S I G N I F I C A N T. They sound like rubbish without it, comparatively. This having been said, 18 of them on EQ with a sub right next to it... not-freakin-bad, man. 8 ohms and reasonably sensitive. I think I'm going to arc & power taper "a-la Keele." Hang em on the wall.