Stupid Cheap Line Array

18Hurts: those links you sent are awesome.

OPC: That's for the advice.

I'm sure you could tackle the EQ in the analog domain, but the DEQ is such a capable device that it's worth 10 times what it costs to buy, and the end result is better than you'd get with an analog filter. If you're building a line with full range drivers you absolutely will need active EQ of some sort.

My understanding of the DCX was that it did work in the digital. Analog coming in (which is probably good since the best digital input that this unit takes is optical, and my Onkyo 3007 has a good DAC), digital convert, processing, analog convert, analog out. Or are you just advising against an analog x-over?

I'm running the lines full range (without a sub) in a very large room, and I get genuinely flat response (-3dB) down to 20Hz.

How do you get down to 20 Hz with a driver that doesn't really produce much down there? Is it just EQing everything level regardless of the output? This seems to open the driver market wide open.

For $3.50/each, It would be well worth it to test out a pair of these drivers, along with others. I tend to forget that not all audible characteristics are measurable.

Greg
 

opc

Member
Joined 2004
Paid Member
Hi Guys,

Thanks for the comments, very much appreciated! Let's see if I can cover the questions asked.

18Hurts:

After I read about arrays, I decided to run a 2-way crossed at around 4,200 Hz to limit beaming. The tweeter line should also limit excessive EQ requirements which is important when used with guitar amps etc.

Very interested in your comments of the 1 to 2 meter sound change. I noted that when I was 1.5 to 2 meters back, testing my 5" woofers "full range" sounded much improved. Can't wait until I can hear the tweeter line come to life as I'm still waiting for XO parts to arrive.

I'm curious to hear what you think of the two-way solution when you get it up and running. I would imagine the tweeter array should have no audible comb filtering from any distance, but that depends on driver to driver spacing.

Do you have any measurement gear to check the results after the passive XO is implemented? Measuring these things is tricky ;)

You stated you tested eight different brands of 3" woofers and FRs--any of them Dayton ND-91s or Tangbands? My only concern is up to 4KHz with efficiency and bass response critical factors. My minimum efficiency is 85dB 1w/1m since I'll be using it with lower power amplifiers (guitar, car amps etc) and need final efficiency at least 96dB at one watt/one meter. The dream 3.5" would run 89dB with decent Xmax and Fs of 65Hz but I'm not holding my breath.

If you want to live long enough to hear them, then I definitely wouldn't hold your breath! You're pretty much spot-on with your criteria, but I can assure you nothing like that actually exists. With a driver that small, there's a direct tradeoff between LF response and efficiency. You can have one or the other, but not both. If you want to run them full range, then Xmax and FS quickly become very important, and you'll have to live with lower efficiency.

Here's what I tested:

Vifa TC19FD18-08
Vifa TG9FD10-04
Dayton RS75T-8
Dayton ND90-8
HiVi M3N
HiVi B3S
Tang Band W3-1053SC
Fountek FR88EX

The Fountek was actually the standout of the group, and I would have used them if it weren't for the cost, availability, and questionable build quality. They sounded incredible, measured very well, and had the best LF response for the given efficiency. If I were to build another array, it would be with those.

Both Vifa drivers sounded exactly the same, which was a surprise to me. I ended up using the paper cone primarily because there was no audible or measurable difference, and the paper cone was cheaper.

The Dayton RS75T was bar-none the worst of the group. There's so little radiating area left thanks to the phase plug, that you get literally no output from the driver. All the EQ in the world wouldn't save that poor thing.

The Dayton ND-90 was the biggest disappointment for me because I was expecting so much from it. On paper, it looks pretty good, but the extremely low efficiency coupled with only marginally more Xmax meant that it didn't really play any lower than the Vifa drivers. It also has the most ragged FR I've ever measured on any driver. When I first measured it I thought something was badly wrong with my setup, but it was actually just the driver. It sounded harsh and abrasive at anything above even a low volume, like it was in breakup over its entire range, all the time.

The Tang Band driver was actually really nice at low levels, but it couldn't keep up with the others at higher outputs. The bottom end was really lacking, but it had a great midband and top end. If you planned on running the array only above 100Hz, this would probably be a top contender.

The Hi-Vi drivers also sounded almost identical to one another, but both were a little meh... :apathic: . Neither sounded all that great, and both got harsh very quickly at higher output levels.

Fully agree with you on the amount of TIME it takes to build such things. Since I didn't know if I was building scrambled hash in an echo box, I made allowances to make it easily to upgrade the woofer line. Pull the machine screws, removed the bezel and cut out the 5" woofer holes portion and glue in a new bezel cut for 3 to 3.5" speakers. (The tweeter lines stay!) The Dayton ND-91 looks to be purpose built for arrays, I just wish it had more sensitivity.

Good call on the replaceable baffles! I actually had mine CNC machined in town by a guy who makes signs and has a large NC controlled gantry router table. I just gave him a cad drawing, and popped in the next day to pick them up. He charged me a comical $75 for the job, and I walked away smiling about how long it would have taken me to them by hand. If you can find this service where you live, it's worth every penny!

Vix:

Don't want to get things off topic, but can't resist: What is the other "hidden by a plant" speaker next to line array?

They're a pair of speakers I made for a friend that I called the BGTB. They use a Tang Band W6-1721 in a TL with a B&G Neo3-PDRW planar tweeter. Both great drivers that I would highly recommend!

MisterTwister:

opc, very nice looking speakers. Do you have unequalized frequency response of an array, from far distance (1meter maybe) I'd be interested to see it.

I do have one somewhere, but I'll have to dig it up. I'll post it in the next day or two.

Is there a reason (besides cost) why you didn't build them up to the ceiling height? I agree with you about choosing good drivers, but sometimes sound quality is not the first priority.

I actually built them for my old home which had 9ft ceilings, and then moved to a place with nearly 11 ft ceilings. Even considering that, I probably would not have built them full height since they'd never fit anywhere else! The cost of 10 additional drivers was negligible, so it really wasn't a cost issue.

gmcalabria:

My understanding of the DCX was that it did work in the digital. Analog coming in (which is probably good since the best digital input that this unit takes is optical, and my Onkyo 3007 has a good DAC), digital convert, processing, analog convert, analog out. Or are you just advising against an analog x-over?

You're absolutely correct, that's exactly how they work. The key is to try and minimize the number of A/D or D/A conversions you're doing, especially if they're not necessary. So if your source is digital (eg a CD or a music server) then you definitely want to run digital into the DCX, and then digital out of the DCX to your DAC. If you do it the other way, then you're introducing two completely unnecessary conversions, which is bad news. IMHO, the second worst part of the audio chain is D/A and A/D conversions, and they're second only to the loudspeaker!

How do you get down to 20 Hz with a driver that doesn't really produce much down there? Is it just EQing everything level regardless of the output?

It is indeed just EQ. In my case, it takes 15dB at 25Hz to get them flat in-room. I honestly didn't think I was going to get any lower than 40Hz when I was working it out on paper, but sure enough, they were good for it.

On the negative side, I'm running an amp that is good for a real 225 watts into 8 ohms, and it clips long before the drivers run out of excursion. I really loved the F5 amplifier I was using, but it just doesn't have the power to drive these.

If you crossed above 100Hz then the lines would actually be very efficient (about 96dBSPL at 2.83V) but as you can imagine, needing an additional 15dB to get down to 20 Hz really takes a toll.

This seems to open the driver market wide open. For $3.50/each, It would be well worth it to test out a pair of these drivers, along with others. I tend to forget that not all audible characteristics are measurable.

Not all drivers are going to be suitable for that kind of treatment. You still need radiating surface and Xmax to get output at lower frequencies like that, so drivers with 1.5mm of Xmax and Fs of 200Hz are not going to cut it.

As for testing though, it's worth every penny. I spent a little over two hundred to buy the 8 pairs of drivers I tested, and it was a very valuable learning experience. As I mentioned above, if I had selected the drivers that looked best on paper, I would have been pretty disappointed with the result. In the end, I sold a few pairs and gave a few away at a local audio meet, so it worked out pretty well.

Forsman:

- Totem Forest

:rolleyes:

Cheers,
Owen
 
Thank you, Owen

Out of the eight you tested, I own the Tang Band W3-1053SC which I use for surround sound. You are correct, they sound good but the bass is quite weak. The 2-way array allowed use of 5 inch woofers for SPL, bass capability and more Xmax. The 15-year old playing guitar drop D tuned guitar with his tongue should be OK. I would not pay the $16 each MSRP but bought in bulk at close out, the $60 for 24 of them eased the pain.

The Mark Audio CHR 70 Generation 3 has great specs, 85.5 dB, Fo of 65.4 Hz, 4.3mm Xmax and is a full range. Alas, it has a giant plastic frame which is 5.3 inches across. Maybe Mark will make a version with a cast aluminum frame cut across one axis to squeeze them in tightly? At least I know that those specs are possible and at $36 each for the CHR-70, they won't cost $500 to get something along those lines.

The tweeter line will start to beam at exactly 9,600 Hz or at the 1.41" center to center distance between them. I'm counting on the ear's reduced sensitivity to 10KHz and up frequencies to make this a moot point for non-critical listening. The Audax tweeters show 90dB at 4 Khz then it starts to rise to 93dB at 8Khz then taper down to 90dB again at 11 KHz. I set up the crossovers to be even at 4 KHz so the expected increase at 5 to 11 KHz will stay in place. After that, I'll have to EQ for beaming which is not much of a problem.

If I ever upgrade the things to twenty 3" driver lines, I'll then ponder the 10KHz+ beaming issues of the tweeter line. If running 3.5" full-ranges beaming at 4 KHz and up does not bother the ear--I don't see myself getting offended if the tweeter line beams at 10KHz.

In theory--the FedEx truck just dropped off my XO and PA speaker parts order so this sucker is going back to making sawdust reality. Jimi Hendrix wanna-be musicians await. :rolleyes:
 

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FYI: Supplement simulations(3-way near-field array) to the picture here-above by using Svante's Edge program:

b:)

I'm not sure I understand. I can understand why the phase goes wacky and gets worse as pitch goes up, but what effects the frequency response like like? Is that all directionality of the woofers equating to a large amplitude addition at LF and little/no addition at HF? If so, how does any line array avoid this? A 3" is going to beam like hell at 20kHz, but most people seem to like lots of 2" and 3" instead of a multi-way system.

I've yet to DL Edge, but ArrayShow doesn't work on my computer and this makes me sad. I'd imagine I could learn a lot from it.

Greg
 
BTW, I know that for arrays, most people bi-amp. In the case that this wouldn't be true (/if someone used series drivers in a normal 2-way/3-way, etc.), what is required for a Zobel circuit? Can one wire a single Zobel over all series/parallel drivers? One Zobel per parallel bunch of drivers? One Zobel per driver?

Greg
 
I've started reconsidering drivers... I've also reconsidered a full line tweeter array with the Apex Jr tweeters. I am worried about the low end of those drivers mashing up with the high end of the woofers. Specifically, I'm wondering if lower frequency combing is more of a problem than higher frequency. For example, lets use a X-over @ 4000 when the C-C distance is 6". That means that anything over @2800 Hz is combing, assuming a 1 wavelength C-C is acceptable (yes, I know that 1/4 lambda is more idea, but it ain't hapennin'). Is that range of 2800-5500 (depending on X-over) more noticeable than OPC's 3900 and up? Is there a particular range that I should avoid?

If you can't tell, I've been tempted by larger drivers, particularly the Aura NS6, used along with a tweeter line. The driver itself isn't horrible above 3-4k, but I'd imagine the comb filtering would get bad.

18 Hurts: how are things going? Is that tweeter line calling the cops yet?

Greg
 
"Also, someone PLEASE convince me not to buy a case of those Sony 5.25" neo-woofers."

You're posting on the wrong forum for help there! PE Tracking indicates that my case arrived today! The closest I can come to helping you out here is to say that the last time I ordered a bunch of <$1 drivers they were almost unanimous in having terrible voice coil rubbing. But I'm suckered in again, hoping that these Sony buyouts will be good enough for silly projects...
 
I've started reconsidering drivers... I've also reconsidered a full line tweeter array with the Apex Jr tweeters. I am worried about the low end of those drivers mashing up with the high end of the woofers.

18 Hurts: how are things going? Is that tweeter line calling the cops yet?

Greg

I'm back!

I finished my 12/48 sealed line arrays and they are resting comfortably in the garage. Those 48 tweeters are a !@#$! to install, wire and create crossovers for but it is finished. Went with a 4,300 Hz XO Linkwitz-Riley point at 18dB/Oct for the tweets and 12dB/Oct for the twelve 5" woofers. Installed a removable aluminum panel with power resistors thermal epoxied to them so I can adjust output from -2 to -10 dB if desired. At this point, they are running wide open as I'll do my adjustments when I find my EQ. :(

I drive them full range for now with a 1981 Pioneer 45 watt per channel receiver. My initial thoughts are they are LOUD! They have a very "big" sound that is larger than life but at least they don't get everything rattling in the garage (except at max power with classical) They do sound better than point source since the garage is metal with wood panels on the inside and the line hammer effect seems to minimize excessive reflections off the walls and cement floor.

There are a few downsides though--with basic tone controls I can't get the midrange smooth, it needs EQ. Not a lot of EQ mind you, but some adjustment in the 1 to 5 KHz bands so it meshes better with the tweeter line. The tweet line seems to be OK, maybe a touch higher at 16 KHz but for the most part, it is fine. I'll set the padding resistors when I find my EQ and do the final setup.

The bass is interesting, quite boomy so I set the bass knob to 9 O'clock and turned the loudness control on. The boom went away and the deeper bass was noticeable although not earth shaking. That is fine, I'll be building a subwoofer to take care of the lower bass issues and take the load off the 30 year old receiver. Cutting out the bass boom helped elevate the mids so it sounds decent, not perfect but much better. The treble comes in and is a bit higher than the 5" woofers, EQ and padding will take care of that.

My C to C distance is 5.625 inches for the woofers or a wavelength of 2,400 Hz. I figure beaming issues from 2.4 KHz to 4.3 KHz give me some of my EQ requirements but it is not the end of the world. It is less than an octave and if I lose sleep or go OCD, those HiVi 3" speakers have a 78mm C to C for 4,400 Hz wavelength so.... there is a solution.

Initially, I was a bit nervous about crossing a 10mm dome tweeter with an Fs of 3K at 4,300 Hz. The LR -6dB slope at the crossover frequency coupled with the 18 dB filter cured my paranoia. There are 48 tweeters in the line so distortion or destruction is not an issue. I don't detect tweeter beaming which would be north of 10KHz since they are packed in tight. My ears lose sensitivity to artifacts over 10K so I'm not worried about it.

My mods are to get some EQ in there to smooth the mids, bring up the bottom end with a subwoofer and pad in some resistance to the tweet line to finish it up. The sub build is next since a party is scheduled in the garage on 11/11/11 complete with BBQ, brew and music. They are garage/party/PA speakers after all.

Had a guitarist buddy of mine stop by and give them a listen. He absolutely loved the "big" sound of them and the huge sound stage. His comment was they sound amazing with bass guitar and those tweeter lines really sing although the mids seem a bit light. When he saw the 10 watt peaks on the old Pioneer's meters, it shocked him how loud they could be at such low power. We discussed it and now he is bothering me about my sub build, finding the EQ and linking in a mixer.

Normally, they are operating at around 1 to 3 watt peaks in the garage. Since I'm walking around, standing up, sitting down or getting on the floor--the line sound works well for my uses. If I quickly stand up I can hear a little beaming in the mids so jumping around on a pogo stick while listening critically is not suggested. The sub and EQ should get the sound quality at the level required so all the time and effort to get 120 speaker drivers working together was worth it.

In the future, I can easily remove the front bezel as it is mounted on a gasket with machine screws. Eventually I'll throw 16 to 24 three or four inch speakers inside to replace the 5" woofers and keep using the sub woofer. That is years down the line, for now they do what I wanted them to do and sound better than I thought. The Sony Neo 5" woofers are on close out from PE at $4.50 each or $2.50 when buying 10+. They are the blue coned ones with the screen grill over them which protects them from garage slop but also stiffens the light weight frames. Don't forget to add a liberal amount of plumber's putty to prevent ringing.

All in all, the line arrays make a unique speaker with a big sound that works in the acoustical nightmare garage. Although not perfect, they have a unique sound stage that puts a grin on my face. My point source HT system in the house need not worry--yet.
 
Ooohh, let me know...

I'd imagine that the $2/each upgrade to the Auras would be worth it, just judging by their flat response. The Sonys could probably kick butt if they were smooth just because with so many drivers you could cut those peaks down. Then again, you're left with a 75 db sensitive driver...

Greg
 
Sorry for breaking into this thread but I'd like to get opc's input on the drivers he used,

Not all drivers are going to be suitable for that kind of treatment. You still need radiating surface and Xmax to get output at lower frequencies like that, so drivers with 1.5mm of Xmax and Fs of 200Hz are not going to cut it.

As for testing though, it's worth every penny. I spent a little over two hundred to buy the 8 pairs of drivers I tested, and it was a very valuable learning experience. As I mentioned above, if I had selected the drivers that looked best on paper, I would have been pretty disappointed with the result. In the end, I sold a few pairs and gave a few away at a local audio meet, so it worked out pretty well.

Forsman:



:rolleyes:

Cheers,
Owen

You have built exactly what I was planning after finding the Roger Russell IDS-25 line arrays. I figured I'd use the cheaper Vifa TC19FD18-08 and get very close. After modeling the TC19 and comparing it to the IDS-25 original it lacked about 4 dB in the lowest regeons. I was looking for the amount of boost needed to get them flat somewhere around 25-30 Hz. Thanks for sharing that. I have a 25 year old Pioneer amp that only puts out 100 watt into 8 ohm so that would be my limit to reach high volume. I could consider only flattening it out to about ~ 30 Hz I guess.

I actually stumbled over this thread in search of a replacement for the Vifa TC19FD18-08. I was pretty sure I was going to use them until I found out the xmax of these is only 1.5mm compared to 2.23mm for the drivers Roger Russell used (Known here in Europe as Vifa 9 BGS 119/8, the Vifa TG9FSD10-08).
Your experience with the Vifa TC19FD18-08 tells me that 1.5mm might be enough after all. I have seen xmax reported as 3mm but that's the mechanical limit. Linear xmax is only 1.5mm.
Damn shame I have to pay about 600 euros for 50 of these drivers over here. I did look at importing but it would come out about the same after shipping and taxes.
Here in Europe there are 2 more names for these Vifa TC19FD18-08 drivers, The Peerless FR35/8 and Vifa 9 BN 119/8. Specs are all over the place though.

Vifa 9 BN 119/8 specs in Europe:
http://www.lautsprechershop.de/pdf/vifa/vifa_9bn119_8.pdf

Vifa TC9FD18-08 specs in Europe, only slight differences:http://www.lautsprechershop.de/pdf/vifa/vifa_3_5zoll_fullrange_tc9fd_18_08.pdf

Tymphany's specs Peerless TC9FD-18-08:
http://www.tymphany.com/files/TC9FD-18-08 Rev1_0.pdf
That last one has different Qts of 0.95 compared to the 0.72 of both examples above. So I guess there are 2 versions of this driver? The other small differences of the first two could be attributed to driver selection and labeling.
I asume you used the last example. It even reports a bigger xmax of 2.55 mm.

Maybe I need to import after all? The most confusing to me is PE lists the parameters similar to the European model (Qts 0.72) but puts up the spec sheet quoting the Qts 0.95.

I am lost :spin: someone help me here...
 
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18 Hurts: Thanks for the long writeup. I would have liked to get back to you earlier, but I left for California for 2 weeks, 3 days after buying my first house. Since then, my head has been SPINNING.

Went with a 4,300 Hz XO Linkwitz-Riley point at 18dB/Oct for the tweets and 12dB/Oct for the twelve 5" woofers.

There are a few downsides though--with basic tone controls I can't get the midrange smooth, it needs EQ.

The treble comes in and is a bit higher than the 5" woofers, EQ and padding will take care of that.

My C to C distance is 5.625 inches for the woofers or a wavelength of 2,400 Hz. I figure beaming issues from 2.4 KHz to 4.3 KHz give me some of my EQ requirements but it is not the end of the world. It is less than an octave and if I lose sleep or go OCD, those HiVi 3" speakers have a 78mm C to C for 4,400 Hz wavelength so.... there is a solution.

Initially, I was a bit nervous about crossing a 10mm dome tweeter with an Fs of 3K at 4,300 Hz. The LR -6dB slope at the crossover frequency coupled with the 18 dB filter cured my paranoia. There are 48 tweeters in the line so distortion or destruction is not an issue.

My mods are to get some EQ in there to smooth the mids, bring up the bottom end with a subwoofer and pad in some resistance to the tweet line to finish it up. The sub build is next since a party is scheduled in the garage on 11/11/11 complete with BBQ, brew and music. They are garage/party/PA speakers after all.

Normally, they are operating at around 1 to 3 watt peaks in the garage. Since I'm walking around, standing up, sitting down or getting on the floor--the line sound works well for my uses. If I quickly stand up I can hear a little beaming in the mids so jumping around on a pogo stick while listening critically is not suggested.

All in all, the line arrays make a unique speaker with a big sound that works in the acoustical nightmare garage. Although not perfect, they have a unique sound stage that puts a grin on my face. My point source HT system in the house need not worry--yet.

It sounds like you'd prefer smaller drivers overall though. Is this simply the comb filtering effects in the midrange?

It does seem like unless you EQ the woofers to hell, you're not going to get great low bass. I think that one of the things that I was attracted to is the FLAT bass response, but I guess you're only gonna get that by cutting out almost all response but the bass like OPC did. I think that the drivers that I chose (the 5.25" ones) are pretty bad for that too (worse than OPC's 3"ers despite the size). For that reason, I started considering those cheap Aurasound 6" neo woofers that are known for their bass and dynamics as a point source, along with the ApexJR tweeter. What I am worried about then will be 1. beaming (6" drivers beam above 2250 and I don't think that I can crossover lower than 4khz at best, even running LR4) and 2. comb filtering. I don't expect audiophile on a pogo stick quality, but 6" drivers running to and above 4k is probably pushing it. Then again, that's only a few % larger than the 5.25's are running. What would you say from experience?

Greg
 

opc

Member
Joined 2004
Paid Member
wesayso:

Sorry for not getting back to you sooner... I stopped getting notifications on this thread for some reason! hopefully I'll catch you in time.

I find the spec sheet fiasco with those drivers to be a huge disappointment from DST. Usually Vifa and Peerless are pretty good with datasheets, but with the 3" versions it's a real nightmare. I basically didn't bother with the datasheets (after reading 4 different conflicting sheets for what appeared to be the same driver) and I just bought them and measured them.

I can verify that the fibreglass driver (the one I think Roger Russell uses) is exactly the same in terms of acoustic response and resonance as the paper cone drivers I used. I've attached some measurements I made of both drivers in the exact same enclosure for reference. The only difference is that one is 4 ohms, and the other is 8 ohms. Both measurement were done at 1W and amplitude is not absolute, but is correct in relative terms.

The drivers in these measurements are these:

Vifa TC9FD-18-08 3-1/2" Full Range Paper Cone Woofer 264-1062

Vifa TG9FD-10-04 3-1/2" Glass Fiber Cone Full Range 264-1064

I can't vouch for any other driver from any other source, as they may indeed be different.

For what it's worth, I really do like my arrays, and fully endorse them if you're thinking of building a pair!

Cheers,
Owen
 

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Hello Greg,

I've been giving the arrays a work out in the garage...threw in an old AR 12" 120 watt ported sub in the corner to give it more punch. Sounds much better but the poor little sub runs out of gas at around 20 watts per channel into the much louder arrays. :eek: The solution is the dual 12" JBL tapped horn sub which should match up with the arrays quite nicely--they are the same height and width within an inch.

Generally speaking, they sound better at about twice the distance away as they are tall--or around 12 feet away. They sound "different" if you are sitting down with your ears in the middle of the array or standing as your ears are at the "top". The treble is there which is great for a garage--but the sound changes.

I've had people over to listen to them and the general consensus is they like the sound. Very "big" sound, very loud but not distorted or tiring. Could use more bass and the midrange needs some EQ but for a sound system that you don't need to locked into position--thumbs up. To check for beaming issues, just stand up quickly and it can be heard as it is there. Generally speaking, the beaming is not an issue for it's intended purpose. To beat the evil beam requires a crossover at HALF the distance of center to center distances but my ears are not sensitive to it. I've built a MTM center channel with the C to C at 0.98 distance and a 1,850 Hz XO and don't notice any beaming. The array I can hear it if I'm moving around--close enough.

Figured going with a 2-way line array would cure the treble issues at 4,300 Hz to 10KHz since after 10K, your ears are not that sensitive to the tweeter beaming. The 2,300Hz when the C to C exceeds one wavelength (to me) is not that big of an issue--the EQ requirement is more noticeable. For garage PA use, the Yamaha mixer I'm going to buy has a 2.5 KHz EQ adjustment and that should be close enough...it needs a boost of 3 to 5dB in that range. Not sure if it has to do with the beaming, the downward tilt that arrays have at higher frequencies or the Sony woofers just do that...but it is an issue. Mariah Carey MTV Unplugged shows there is an issue there but for rock music it generally is fine.

The Aurasound 6 inchers would make a very LOUD array! Alas, when I was looking at them my specs where no major beaming for more than one octave so I had to pass. The other requirement was poly coated or poly cones with rubber surrounds to resist flying liquids and variations in temperature better than foam surrounds. I built them to last 30 years.

If you want the speakers for PA type output or really high output, the Aurasound 5.35" poly cone neo woofers are a better option than the Sonys. They naturally roll off at 4,200 Hz smoothly so a filter is not required if bringing in the tweeter line around that range. They are about 3dB louder than the Sonys, handle around 40 watts RMS and have vented magnets and would sound better. I've been eyeballing them at $8 each when buying 24+ at Madisound. The 5.125 diameter equals a wavelength of 2645 Hz and the output of the woofers increase in that area until rolling off at 4,200 Hz. (less midrange EQ required) If Madisound has a 50% off sale on Black Friday--I'll buy 30 of them!

Full range arrays? I have run the arrays with music that contains sub 20 Hz information and it does have output--very low output but no funny noises at 40 watts into the 12 woofers. To get 30 Hz performance would require a very long stroke woofer and heavy EQ in a sealed box (mine are sealed) others have done it and it works--but not worth it in my case. 5" woofers can only get you so far even if you have 24 of them! If attempting a full range array, you MUST have EQ capability--1/3rd octave at a minimum. I don't have an EQ connected to the system yet so use a subwoofer to "cheat" and it works well.

Eventually, a decent 4" mid-woofer that has decent Xmax and efficiency might show up...one designed for arrays. My box is done, the tweeter line will remain there until I die so at least the hard part is done. Figure in a few years, the right 4" midwoofer will arrive at the right price and I'll upgrade the arrays. Or not! My major complaints is in the 1.5K to 4K band with EQ being a solution and I need serious bass support so I can play classic music in the garage. They sound decent with classical and once the deep bass and midrange EQ gets sorted--I'll probably be content for garage sound.

Would I want something like that in my house? I've thought about it and they would be great surround speakers but I would not want them for left/center/right. They image well but there is a slight "haze" to the sound--they don't have pin point perfect imaging and that is what I prefer for the house use. The big sound, even treble response and high output without getting the metal garage walls interacting too much make the arrays a keeper for that area.

For home use, I'll be looking into Synergy horns eventually...
 
18: wow, pretty complete review there.

I did think about the paper/foam longevity issues, but I doubt I'm going to have the speakers that long. I don't want to throw money away, but I don't see a pair of speakers with such... how do I say... needs, proclivities, etc. staying in my house that long. Honestly, I'd like a pair of speakers to mess around with and maybe even loan out as PA equipment. Not that I think that much of my design, but it would be cool to go to a bar with a PA system that doesn't sound like screachy scrambled hash. I despise those 2-way PA horn junkers. Also, I realize that that's where cheaper line arrays belong. PA. Not refined enough for home, much better and cheaper than 2-ways.

The other hope, for the time where I use them for my home, is to use them for left/right channels set up as corner arrays. Pin point imaging is really wonderful, but very grand dynamics can make an action movie or shooter videogame truely epic, especially witha 58" Samsung plasma (ok, 58" isn't that big, but my room isn't either). In fact, that's a bit of concern to me as I will probably only have ~12 ft between the speakers and the center listening position.

The 6" drivers really make me want to find a decent/cheap 2" midrange. Then again, why don't I just suck it up and use higher quality drivers at that point... cost. And those 6" Auras at 16/side is going to run something over $200 in drivers, so this is more of a mid-priced project (for me, anyway). But I really don't want to run subwoofers, especially since then the PA use becomes a problem (line and point source mixing) and few subs can take that kind of power to keep up with a line array at any distance.

I'd imagine that OPC did his homework pretty well with those 3"ers because they're some of the cleanest and most capable down low and small enough to run up high. Especially for home use, the flat bass at expense of efficiency really isn't a problem. OPC, I do wonder how those arrays you built would do with a tweeter line as well. With the setup, you could pretty much use as small a tweeter as possible.

Greg
 
This looks like more than 1.5mm Xmax to me:

Aurasound NS525-255-8A Excursion - YouTube

I did message this user and he was using these drivers along with an unknown tweeter line, crossed over at 60hz LR8 (but getting 103db/W for the whole line). He went on to state that they sounded like $30 5.25", the Xmax ratings were way small and efficiency was higher than published. He's using them in a CBT array.

Sounds good to me to run full range at much lower overall sensitivities (especially considering my Onkyo won't do well to room correct 103 db speakers anyway. Then again, if they're that good, but still going to make me want a midrange and more excursion/low frequency bass, why not get the 6" version and find a good 2-2.5" midrange? Every time I think about this, I really really want to run 3-way again. Does everyone get that feeling?

I think I'm gonna pony up on a bunch of the driver we've all been talking about and take a listen. Sometime after I pony up and get those new rotors for my Mazda... I'm told brakes are more important than speakers.

Greg
 
Greg,

It all depends on what the system's use is and priorities in the design. To me a "garage system" is old junk--cast offs from time past that sit around collecting dust. The 1981 Pioneer receiver was a gift a few years back and the 1993 Sony CD player was used back in the day prior to DVD players. The 1999 Acoustic Research 120 watt 12" ported subwoofer was used before I built my 15" isobaric passive radiator HT sub etc.

Nothing in the garage system is from this millennium yet alone this decade! ;) The speakers are "new" but consist of factory close out stuff and I figured it would be a good experiment. That stack of old equipment is out of the house and in the garage--makes my wife happy.

The winner in the design is that 6 foot tall 48 tweeter line array with 18dB third order crossover--many comments on that. My musician buddies mention that the treble is very broad and can be heard when moving around and LOVE how it operates. The tweeter line allows the speaker to put out high levels but it won't smoke your ears when walking or dancing past it. The system is loud but allows you to get very close to it without blasting your ear drums. It requires physically putting your ears on one of the 48 tweeters to make sure it is operating. Try that with a horn! :eek:

Cost is a HUGE issue with arrays--that would explain why I never see them in audio establishments. I bought 100 tweeters for the project so cost is a very large factor there. 25 bucks a tweeter X 100 becomes serious money quickly and there is always that voice in the back of your head--you are blowing $2500 on something you have no idea if it works. The JBL/Audax close out 10mm tweeters at $50 for 100 (DIY forum discount) allowed me to try without breaking the bank if I hated the sound of the devices.

The CLA or corner line arrays mention the destructive/constructive "tilt" in frequency response. That concept is very real and evident with the twelve 5" woofer/48 tweeter line array. The tweeter line should be at least 106 dB at one watt with the woofer line at 96dB or burn paint territory. It don't work that way though--the tweeter line runs a little hot but the tilt calms it down. The multiple woofers DO create a midbass/upper bass boom but my bass knob takes care of that. The only thing left is the midrange tilt which must be EQ'd out. As I stated, the sub in the corner crossed at 80Hz takes care of the deep bass issues but I need much higher SPLs to keep up.

All in all, it is a very fun form of sound that matches well with beer and BBQ--not a wine and cheese system. If you enjoy tweaking speakers and want something that exceeds the sum of it's parts--start off with close out parts and throw one together, you just might like it. If it horrifies your sense of sound, at least you won't be out a large amount of money. There is always a use for a speaker that puts out fairly high amounts of SPL and it works well for parties. :drink: Amazing how it sounds better after a few cold, frosty ones. :superman:
 
wesayso:

Sorry for not getting back to you sooner... I stopped getting notifications on this thread for some reason! hopefully I'll catch you in time.

I find the spec sheet fiasco with those drivers to be a huge disappointment from DST. Usually Vifa and Peerless are pretty good with datasheets, but with the 3" versions it's a real nightmare. I basically didn't bother with the datasheets (after reading 4 different conflicting sheets for what appeared to be the same driver) and I just bought them and measured them.

I can verify that the fibreglass driver (the one I think Roger Russell uses) is exactly the same in terms of acoustic response and resonance as the paper cone drivers I used. I've attached some measurements I made of both drivers in the exact same enclosure for reference. The only difference is that one is 4 ohms, and the other is 8 ohms. Both measurement were done at 1W and amplitude is not absolute, but is correct in relative terms.

The drivers in these measurements are these:

Vifa TC9FD-18-08 3-1/2" Full Range Paper Cone Woofer 264-1062

Vifa TG9FD-10-04 3-1/2" Glass Fiber Cone Full Range 264-1064

I can't vouch for any other driver from any other source, as they may indeed be different.

For what it's worth, I really do like my arrays, and fully endorse them if you're thinking of building a pair!

Cheers,
Owen

Thank you Owen for this reply. I had done some inquiries and came to the conclusion that all Vifa TC9FD-18-08 3-1/2" divers sold today are the same. I have ordered the drivers and allready have 2 of them to check out.
I decided to go ahead and build the arrays, partly because of your replies to this thread. I even had email contact with Mr. Russell about my planned project and he was very supportive. The drivers he used in his IDS-25 are no longer made and where a shielded 8 Ohm version of the fibre glass driver you tested. The specs are very close to the paper cone driver and x-max is about 2.55 mm for both.
Can you describe the sound of your arrays in comparison to the ones 18Hurts built? I'm just curious if better speakers make the difference.
Also you stated you have the speakers sealed as a group of 5 (the ones that are hooked up in series. How did you determine that way of building the box? The original plans from Mr. Russell has one big box with ribs every 2 drivers with two holes in them aboit 1-1/4" in size.