# A-Pillar Line Array



## Guest (Jul 12, 2005)

I kinda like line-array speakers ... or I guess more accurate to say I'm very intrigued by the possibilities. Mostly, I think, because they may be the best dynamic approximation to my most beloved Martin Logan CLS electrostats  Wide horizontal dispersion, narrow vertical dispersion, rather loud listening levels with little diaghram movement, no crossover near the vocal range, etc.

Well I'm sure I'm not the first to consider building a line array of wide range drivers in the A-Pillars. But i'm thinking that maybe we now have access to the right technology to pull it off. Here's the issues, and possible solutions, as I see them :

1. Driver choice. Why, the Aura NSW2 Whisper of course  Hats off to DS-21, and npdang of course, for advocating & pioneering the use of this little marvel in the car. Yes, it has higher-than-expected distortion (given it's large xmax) ... but it's mostly 2nd harmonic and, as suggested by DS-21, that ain't all bad ... at least for an old bottlehead like me. Plus, with enough of these little babies in an array, each driver works less for a given output level, minimizing the distortion. The energy storage near 2kHz, evident in the CSD/waterfall, may be more troublesome. I wonder how much EQ can help ... SL builds a little notch into his Pluto electronics ... not at 2kHz, but closer to 4.5kHz I think to tame a peak observed with the NSW2 mounted in the PVC pipe.

2. Midrange cavity resonance, behind the driver. I've always maintained that what goes on _behind_ the midrange cone/dome is more important than what's in front. May need to drill vents in the A-Pillar, use good damping material, etc. to control that rear-wave from the Aura Whisper.

2. The A-Pillars are not vertical ... the top being much closer to the ear than the bottom. But here's where things can get really interesting  We now have access to digital time delay technology ... not _delta_ alignment in this case, but _parallel_ alignment (Delta means different delays for left/right drivers, parallel means same delays for left/right drivers in order to align drivers in the same stereo channel). It's quite possible to give each driver, or, more economically, maybe each pair of drivers, it's own time alignment & amp channel. One can therefore delay the drivers, as you climb up the array, for matched arrival time. In other words, we build an electronic "delay line" into the A-Pillar array to compensate for it's non-vertical angle. Yeah it's possible to do it analog, even passive, but that Quad ESL63 wasn't built overnite, if you know what I mean  

3. Windshield reflections. Perhaps not as bad as one might think. If anyone labored through the ECA clinic thread, you'll remember that image theory tells us that you can model the reflection by placing an "image" or 'phantom" driver where the observed reflection is in the glass, then conceptually "remove" the glass, and get the same radiation pattern. In other words, windshield reflections really mean each side has _two_ line arrays. This may wreak havoc on horizontal dispersion, but might also help attenuate the close array more than the far array ... which ain't all bad for combatting side bias.

Why bother? Simple ... I think we're always looking for ways to create a realistically HIGH stage in a car. No, I haven't heard the best kick panel cars in the world. But I've gotta agree with DS-21 on this one ... tonality & stage height are too often sacrificed at the pathlength altar. It's not a tradeoff to be taken lightly.

Anyway, congratulations npdang on a GREAT forum. Very helpful, informative, happy to be here. And I promise to stay out of any political debates


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## newtitan (Mar 7, 2005)

now thats a first post!!!!!

glad to see you around these parts 

I too have been considering this

I bought 4 aura ns3's to model just this possibility (two in each pillar)

not sure theyll fit so I bought some backup vifa 4-1/2"

I do think ideally the ns2 would be easier to mount , but the response of the ns3 seems more attractive

now if I could only find a way to mount them withou the flange


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## npdang (Jul 29, 2005)

Excellent post!

Have you by chance heard any of the M-design (Monster Cable) line array speakers using the Aura drivers? I managed to sneak an audition over at the local Best Buy (lol) and unfortunately they had it setup in the worst possible condition.


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## low (Jun 2, 2005)

the wolfman - always full of wonderful information and class. i think we're all lucky to be involved in car audio with this guy posting. great post mr werewolf.


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## Guest (Jul 13, 2005)

Thanks for the kind words guys ... but the credit here goes to npdang for sharing his time, knowledge & resources  

Haven't heard the M-design array yet ... but I did listen to a McIntosh array at CES 04. Not sure what drivers, but I wasn't very impressed with the tonality. Stage was decent, however.

More than a few DIY'ers seem to have had some success with Jordan line arrays ...


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## blackreplica (Mar 14, 2005)

muahahah mr wolf i knew it was only a matter of time before you ended up here.

i was also considering a mini-line array of 2 NSWs per channel, dash mounted and firing away from the windscreen. Your GURT thread really helped me make the decision to go this route. My aim is to minimise secondary sound sources (as per your discussion, i want the primary source to overpower the reflections) Ever thought about mouting it in the corner of the dash, against the windscreen, and facing the listener instead? That way you avoid all the possible nasties with glass reflections and such. Imagine an array of NSW2s going from dash to ceiling, how cool would that be :shock:


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## DS-21 (Apr 16, 2005)

Have you started this very interesting project already? I think it's a neat approach over all, and I'm all the more in admiration because doing it right is far beyond my technical competence right now. Would you be using commercial processors or fabbing your own using, say, DSP chips intended for multichannel receivers? Amp-wise I wouldn't think it's an issue. Apex Jr. has some surplus amps that would probably work fine, or you could DIY your own mobile gazillion-channel "Gainclone" chip amp....

I’m curious as to why you chose the Aura Whisper over the Aura Cougar for this application. The Cougar allows ~15mm closer C-t-C spacing, thereby pushing the onset of comb filtering higher up in frequency and probably extending your usable top end by a third or so. (That’s a third in the musical sense, not 33%...) Keeping CTC spacing as tight as possible is why most DIY line arrays use planars/ribbons, and commercial ones such as the Pipedreams use tiny domes. The Cougar also might be slightly less deep, allowing a smidge more flexibility in damping the backwave. (I damped mine with a layer of 2-ply cashmere from a Burberry scarf that was attacked by moths over the rear grille, and an XL cotton ball ball-sized wad of polyfill right behind that.) Then again, I’ve never played with the Cougar, and SL did pick the Whisper over the Cougar for his Pluto when either would’ve probably worked....

As for getting CLS-like sound, might it be possible to get some sort of dipole up front? (Yeah, I know, stupid question  ) IMO, the main effect of line-source radiation in a nearfield setting is to make sonic images universally bigger. The glorious stage depth and palpability you (and I, and our Maggie-using host) find in planar speakers seems to come largely from their dipolar radiation pattern, I think. I base that thought on my own experiences auditioning three monopole line sources and two dipole/cardoid point sources, albeit in different rooms. (The monopole lines were the Linus by Jim Griffin and Rick Craig, set up by Dr. Griffin, and the commercial speaker from BG that used their 50” planar. The point sources were the Quad ESL-63US, Siegfried Linkwitz’s Audio Artistry Dvorak, and the Gradient Revolution.) The dipole/cardoid point sources had the magic, the monopole lines were both neat neat but to me ultimately more Starbucks than Julius Meinl.

PS: If you don't see a reply from me for a little while, I'm not ignoring you. I'm going to be in London for ~10 days to attend a cousin's wedding, do some shopping, and check out a few rental property prospects....[/img]


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## Guest (Jul 13, 2005)

Hey DS-21  Well, this particular adventure (like so many for me in our captivating hobby) is just in the "thought-experiment" stage ... at least for now. I do agree completely on the Cougar advantages though. Just maybe sometimes when you really want to crank it, to tear your skull open, ya know ... one might wish for more midrange output :wink: 

It is a bit of an issue finding an existing processor with enough time delay channels to realize the full potential of the idea (assuming there's any real merit here). But a few home-based processors are linkable, so I'll keep thinking. But yeah, little power amps aren't hard to come by ... maybe even something like what SL cooked up for Pluto, for each Aura driver. It's just so tempting to think that we might be able to electronically "stand-up" the pillar (with the appropriate delay-line) to realize a vertical line array, at ear level, in the car. 

Anyway, have a safe trip. We've certainly debated many things not related to car audio in the past, but please do exercise some care in London. Please keep your eyes open, I'll promise to keep my heart & mind open


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## Guest (Jul 14, 2005)

some more thoughts on the delay line ...

What's really needed is a (conceptually) simple "digital delay line". Simple digital memory (FIFO, RAM), "tapped" for each driver in the pillar. But then, of course, each driver needs a DAC & power amp. Not much power for each single driver, of course, so maybe something like the chip-amp LM3886 used by Linkwitz in Pluto. Perhaps each driver won't need it's own separate EQ ... maybe perform a combined or "group" digital EQ before the delay line.

Alternatively, maybe this is a good use for the new Alpine F#1 PXI-H990, which can somehow be linked to another one for a total of 16 channels. Not a cheap option, but certainly a more promising application than DVD-Audio  I gotta learn more about this new Alpine processor. Anyone know where I can find a PXI-H990 Owner's Manual online? The Alpine site doesn't seem to have it ...


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## DS-21 (Apr 16, 2005)

werewolf said:


> Hey DS-21  Well, this particular adventure (like so many for me in our captivating hobby) is just in the "thought-experiment" stage ... at least for now.


The only things in this hobby more fun than thought experiments are listening and discovering either that you were right, or that you were wrong but now you know why....  



werewolf said:


> I do agree completely on the Cougar advantages though. Just maybe sometimes when you really want to crank it, to tear your skull open, ya know ... one might wish for more midrange output :wink:


True, but as long as you keep your crossover reasonable I don't know how big an issue would be. However, there probably is a good reason SL went with the Whisper...



werewolf said:


> But a few home-based processors are linkable, so I'll keep thinking. But yeah, little power amps aren't hard to come by ... maybe even something like what SL cooked up for Pluto, for each Aura driver. It's just so tempting to think that we might be able to electronically "stand-up" the pillar (with the appropriate delay-line) to realize a vertical line array, at ear level, in the car.


Actually, now that I've thought a little more about it, too, doing that actually shouldn't be that hard. I don't remember the model number and I've since sold the piece, but in the late 1990s Bill Burton recommended that I try rear-fill delayed using a "pro audio" processor by Roland, and dammit if that didn’t do more than anything else I’d tried to flesh out those half-left and half-right images. Surely that box (assuming the delay steps aren’t too coarse) or something similar could be easily applied to your concept. However, IIRC it was a 2-channel processor (or at least I only used two channels) and 5 or so of them would just take up a shizzle-ton of space. That’s if why if you've got the time and inclination it might be neat to use two AV receiver DSPs that combine individually settable delays for 5+ channels each and some rudimentary EQ functions with a global DAC, and fab a bespoke delay box/DAC using them. That's a level of involvement in this hobby far beyond my competence, so I don't know exactly what's involved, or if those parts are commonly available. Given my academic background and time constraints, it's also a level I'm never likely to be able to reach. I greatly admire those with the chops to do it and do it well, though.



werewolf said:


> Anyway, have a safe trip. We've certainly debated many things not related to car audio in the past, but please do exercise some care in London. Please keep your eyes open, I'll promise to keep my heart & mind open


Honestly, I'm far more worried about the absurd Communist-style self-criticism session in place as airport so-called security by the spiritual heirs to Leonid Brezhnev currently running our government than I am of any trouble once I'm in the UK. I've got running the gauntlet down to a science by now - big orange flag on the Powerbook so the TSA jackboots don't throw 12 baskets on top of it and try to carry it away while another agent restrains my attempt to stop them (again), drawstring trousers so I don't have to wear a belt, no writing utensils on me, ceramic-case watch, driving mocs that don't have any metal in them, unlined sportcoat, and so on - but nonetheless I still arrive four hours early because I’m invariably flagged by the jackboots for the crime of having brown skin. Assuming Comrade Gonzales’s thugs don’t whisk me to a secret gulag or something for possessing a functional mind, the most ominous potential danger for me is the cuisine. When this cousin's sister married, the caterers for one of the functions gave about 300 people food poisoning; hopefully they’ll use a different one this time. More flippantly, I run the likely risk of forgetting when I see the prices at Turnbull & Asser's summer sale that the UKP is worth about twice as much as the USD until several minutes after the charge plate's been scanned.  
But seriously, "terrorism" is something Americans badly need to keep into perspective, despite (or perhaps BECAUSE OF) the obvious incentive of the powers that be to stoke mindless fear in our population and thus win their crusade against our civil liberties. The entire UK had considerably fewer victims of violent crimes including terrorism per 100,000 people in 2003 than we had people per 100,000 murdered or injured by non-commercial trucks and SUVs over the same time period. Despite the horrific efforts of a (thankfully incompetent) clique of four madmen that will be true in 2005 as well. So ultimately I like my odds once I'm there better than I like my odds driving to and from the airport on this end.


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## Guest (Jul 16, 2005)

Alrighty then. What we need is a plan of attack on this idea.

I think the first step is a "proof on concept". Nothing particularly fancy, pretty or (hopefully) expensive. In this experimental phase, we don't even need car-based processors or amps. What we do need, is an A-Pillar lined with good candidate drivers ... like the little Aura Cougar suggested by DS-21. We're contemplating ribbons as well .... but that seems more expensive (at least, at first glance) and time consuming. Plus, I think we'll want something closer to full-range drivers to really flush out the idea.

I've got a Honda Civic with pretty accessible A-Pillar trim. And I've got some smarts, and a bit of capital ... but precious little time  So I'll just outline some more thoughts for now, cool?

It's quite possible, I think, to fit 16 Aura NS1's in a 24 inch A-Pillar. In a Civic, the A-Pillar trim comes off pretty easily. Some ribbing on the back side would have to be gutted, that's easy. Then, the array must get attached ... drilling & screwing. I'm not sure that it makes sense to ultimatley mount the array to the trim, rather than devise a more solid mount to the A-Pillar metal and just use the trim for cosmetic covering. But remember ... first step is proof-of-concept.

Now, how to drive the array? We'll need a good A-B comparison, of course, with & without delay. Without delay is easy : sixteen 8-ohm drivers can be wired to present a final, non-delayed load of 8 ohms. Somebody can describe this for homework 

Delay options, for proof of concept. Yes, it's possible to do a "passive delay line", of varying degess of complexity & accuracy. In it's most simple form, the passive delay line would look like a series inductor and shunt capacitor between each driver up the pillar. If you think this would present a very low impedance to the amp at DC, you're quite correct. And hence we see the first issue with passive time delay : it's typically only approximately valid over a certain frequency range. But the Aura's will need to be high-passed at 200 Hz (at least) anyway, so I'll give this option some more thought.

Digital delay still sounds attractive to me. The ultimate form would be a custom digital delay line, probably operating at 96kHz or 192kHz (higher sampling rate through the digital delay line means better delay resolution). Of course the fundamental digital audio signal would be created by upsampling to 96kHz or 192kHz by ASRC ... another big topic, favorite of mine  Yes, you would need a battery of DACs & amps, but each amp is pretty low power so the ultimate space & cost wouldn't be too bad. But I'm getting ahead of myself ... proof of concept needs some off-the-shelf processor with buku channels of delay. Good news is, can be a home processor ... hell we're just gonna fire this thing up in somebody's garage to prove the idea first  Can even use some cheap, low power home amps for proof of concept.

Anyway, just a download of thoughts-to-date. Who's got some time, and some A-Pillar trim from their vehicle, to experiment? I'll supply the Aura cougars for anyone interested to experiment & report the results. I'll also look for the right processor ... home or car ... to help us through proof-of-concept. Of course, any help in finding a processor with maybe 16 delay channels, with enough delay resolution (at about 1 foot per msec, we'll need delay resolution well below 0.1msec) would be great too!


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## blackreplica (Mar 14, 2005)

maybe someone could use a couple of daisy chained behringers? How about mounting the drivers such as to incorporate a natural time delay? eg driver on top of line array is as far back as possible, and the line sort of approaches the driver as it goes down to the dash. Would take some fancy fibreglass work though. Or maybe someone could use a shorter line, say about 4-5 drivers so that the PLD when comparing the top and botton wouldnt be a big deal and we could skip the TA step altogether. As long as the line covers the listening position, and maybe a couple of inches above and below it should be no different from a longer array? I recall in jim griffins Line array white paper that you only need to make a line as long as it covers where you are listening from. or maybe i misunderstood


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## spaceman_spliff (Jul 15, 2005)

why run it up the a-pillar? Why not skip time/A...and just run it up either the front part of a door (yes i know furter ahead of the kick drivers) or from the bottom of the apillar, in a nice stright line down to the bottom of the dash or floor, i know i could do this in my truck. I would attempt this in my car if it was a flush line, and not an pillar angle dealie-O. 

oh and I have no idea how to delay such a thing, way out of my league, but I have no problem tearing up my dash more to sink the front face of the line flush with the dash.

I am scared to use a driver that small that i've never heard...anyone give me some pointers on what people normaly use these drivers for, and if they really sound good enought to hang with their big-boy friends in ones (my) ride?


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## spaceman_spliff (Jul 15, 2005)

*Hats off to DS-21*

WoW a real intelectual!

aka not a sheep: nice politics, self-thought, and articulation.

Thank you.


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## Guest (Jul 16, 2005)

Spaceman, running up the A-Pillar places the line array at ear-height. Same reason most people lift their speakers up off the floor at home 

Furthermore, running the line array from dash-level down will not avoid the time delay issue. The fundamental issue is not so much the angle of the pillar, but the arrival time from each driver to your ear. Even with a purely vertical array running from dash-level down, each driver will have a different arrival time to your ear. You'll benefit from a time-delay line in this case to "steer" or "tilt" the dispersion pattern toward your ear.


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## Guest (Jul 17, 2005)

I just saw a thread on line arrays (in cars) over on carsound. Some interesting challenges for near-field listening, of course, especially in a small, reflective environment. An interesting reference was quoted :

http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

Still haven't read the whole paper in detail, but one intersting technique described is "power tapering" the array, as a simpler alternative to delay tapering.


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## Diru (May 23, 2006)

you taken my thunder lol

now my secert it out

are ideas are not so dissimular

i also have the array bug, very nice sounding when done right. Or as close as possible.

http://www.diymobileaudio.com/forum/showthread.php?t=17960


im starting small with this idea, but I am usen the glass to direct the planers. from the seat looking ahead at the glass you can see that the planers are at ear level. 

I still might rework it to a MTM up there.


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## Weightless (May 5, 2005)

I am really interested in doing an array also. 

What kind of amp options are out there for running 6-8 pairs of cougars or whispers(which madisound is sold out of right now). 

Right now I have a PPI DCX-730 for processing, which I might buy another one to add another 6 channels of delay giving me a total of 7 channels of mids per side (the farthest mid doesn't need time alignment), and if I do pairs of cougars per channel, that would give me 14 mids per side.

Geez, the amp rack on this is going to be huge.

Is there any reason why there needs to be a certain amount of speakers per side? Would 6-8 work or to do an array correctly, more drivers would be needed?

Last question, what about multiples of these amps to power the array:

http://cgi.ebay.com/150W-Motorcycle...ryZ39732QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


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## Oliver (Jun 25, 2007)

Has anyone implemented a "Line Array"?


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## t3sn4f2 (Jan 3, 2007)

Bump for a good read.


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## jp88 (Jun 25, 2007)

a$$hole said:


> Has anyone implemented a "Line Array"?


That depends on your definition of implemented. I have 2 line arrays in my vehicle. I only wish I had a setup to do some measurements  Im fairly happy with the results of the experiment to this point, but I have a bit more work to do before I will be finished


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## fish (Jun 30, 2007)

t3sn4f2 said:


> Bump for a good read.



Short but sweet. I wish this one would've been one of those 500-post 12-page threads.


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## cvjoint (Mar 10, 2006)

Wait...that was it? I too was hoping for some more action.


Let's see some line arrays or by God I'll get one done by the end of the month and report back!!!!


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## cvjoint (Mar 10, 2006)

Done! Copied from my thread as I got lazy. 

First some pictures.

This was the *single Faital Pro 4"* on the test baffle. I mounted it right next to the tweeter. This way I can still use the baffle for the line array. It just so happened it helped staging too since it was at ear level and closer to the tweeter and therefore a better point source.










Once I'm done with the test baffle they can mount right on the pod for an even more stealth look. 

For now on the test baffle they are. *Line Array!*:










The paper cone treatment gives them quite a bit of shine for a paper cone. I was coming down from the top of the parking structure and I kept staring at how gorgeous they are as the parking structure lights illuminate the cones. 

Phone camera doesn't do it justice but:










Tests are done from the driver's seat. Only the right pod is tested, and it's about 1 meter away from the mic. 

*FR Faital Array vs. Faital Single*










Theory predicts 6db gain when mounted in a line array at 1m. The pod is about 1 meter away. I get anywhere from 2 to 12db more. Maybe the extra gain in low frequencies is due to coupling and the loss up top is due to comb filtering, I don't know. 

Talking about comb filtering, when I had the single mounted I took a pic of the FR at higher resolution just to see if comb filtering could exist at *1/24 octave smoothing* but not at 1/6 octave like I usually test. The ear is generally believed to hear sounds as if 1/3 octave smoothed. Unsmoothed looked too nasty to even overlap imo. 

From the overlap above it seems that even if comb filtering exists it is not audible. In this graph I can't even see a trace of it at 1/24 octave smoothing. I'm not going to be worried about it and cross wherever. For now I'm ok with 6.3khz. 










Also on this topic, the *mic SPL level was right at 6db* more than the single, just as predicted. 

*THD @95db:*









*THD @100db:*









*THD @105db:*









*THD @110db:*









Heck, more! That's a single pillar pod crossed down to 200hz!

*THD @115db:*










*95db* Excelent! 
*100db* Excelent! Most of it under .3%!
*105db* Excelent! All under 1%.
*110db* Some problem areas begin to appear, 2% distortion at 200hz and 630hz. At 200hz the distortion is probably motor induced from the need for higher excursion. The 630hz is probably my car acoustics. The rest is under 1% as well. 
*115db* Under 3%, amazing. It was so loud it started being annoying even with ear plugs on.


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## 60ndown (Feb 8, 2007)

way to bump a 6 year old thread


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## dbiegel (Oct 15, 2006)

George, very interesting!! I'm thinking about going this route as well...

A few questions for you:
1) How does it sound so far compared to the Neo8s you had? 
2) Given the 6db gain, I wonder if something that can play lower but is normally inefficient (e.g. Aura Whispers) would be worthwhile? What do you think?
3) As far as aiming the line array goes, mine would have to be cross-firing. This might help with side bias... but I wonder if it would sound good?

I'm thinking to use the new HiVi BMR12 in an array, with tweeters too, since it would make for a super easy install.


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## cvjoint (Mar 10, 2006)

dbiegel said:


> George, very interesting!! I'm thinking about going this route as well...
> 
> A few questions for you:
> 1) How does it sound so far compared to the Neo8s you had?
> ...


1 is a tough one. I didn't really run the Neo 8 that low. I do however have the same tests done for it (THD +FR) on my thread. I would say the BG planars still have better attack if that is the word. I would imagine the decay and impedance is better. Strings for example are not as vibrant with the cone drivers.

On the other hand these are very very low distortion when used in pairs and they take up the same amount of space as a Neo 8. With a combined SD of 127 it's like having a high efficiency pro audio midrange on the dash. The vocals are very meaty. It's all low THD. I started with a 3" Peerless and it sounded tiny, doubled the surface area to the single faital, and then doubled again to the line array. Everytime the sound got more robust. If I could fit anything it would probably still be the Neo10 but I think the line array does better in the low midrange and does not compromise any of my windshield viewing area. 

2 Not for me. The smallest I'd go is the 3" Faital. I was originally going to try the Peerless which is a very nice 3" in pairs as well. I decided against it since the singles would noticeably lose steam at mid levels. THD creeped up from 200hz to 1,200hz, it was very audible and at times they cracked and popped with dynamic songs. Of course going three low sensitivity 3" might be worthwhile. 

3 I handle side bias with TA, EQ. and gain. Cross-firing makes for odd nulls IME that you can't really tune out. You may also run out of EQ. steps if the reflections are too much. This is something you may want to temporarily mount and test to see how bad it is when you sum up the channels. You can try a noise track RTA, L, R, then both at the same time.

It seems to be HIWAVE btw, which is something I never heard of. To me the FS is a bit high for covering the entire vocal range and then you don't really get the efficiency either. It's a square! I dig it in multiples though. It would just be risky, we know next to nothing about this driver. BTW, Faital CS just emailed me the Klippel for the Faitals! I'll post it in my thread later. It looks fantastic, especially for $40.


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## dbiegel (Oct 15, 2006)

I can't wait to hear it in person!! Please keep us posted as far as how it sounds once you have more tuning time on it etc. I'm curious how this approach compares to a conventional setup. This topic has been talked about, but very few people seem to have attempted it. It seems to be the best of all worlds as far as SD, THD, and efficiency, and you get some directivity control, too. 

I guess the better attack time of the Neo8s makes sense given the almost zero response/decay time. However, was that with the 12k peakiness completely removed on-axis? I've found that it can give a false impression of speed and detail if not fully removed, even if run off-axis, some reflections still have it. Could try giving the Faitals a big bump at 12k and see what happens. 

I've officially decided to go the a-pillar line array route as well. I'm trying to work with a tight budget and I just don't have enough space on my pillars to integrate the 3" Faitals or any 3" for that matter, let alone the Neo8 (trying to keep it OEM-looking). I just scored a great deal on a set of 16 (possibly more) Aura NSW1's (Cougars) and 8 NSW4's. The nice thing about the Cougars is they're tiny and shallow, so I can arrange them however / put them wherever I want. Supposedly with enough of them, you can cross them around 200-250hz.

My plan is to use somewhere between 3 and 8 Cougars on each a-pillar in a vertical array. How many do you think I'll need?

Then, for the center channel, I'm thinking somewhere between 2 and 4 NSW4's plus some Cougars... I really want to make this a two- or even five- seat system.

If anyone has thoughts as far as where on the a-pillar to place these (thinking bottom/as far away from me as possible) or general comments on this plan please share them here.


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## cvjoint (Mar 10, 2006)

dbiegel said:


> I can't wait to hear it in person!! Please keep us posted as far as how it sounds once you have more tuning time on it etc. I'm curious how this approach compares to a conventional setup. This topic has been talked about, but very few people seem to have attempted it. It seems to be the best of all worlds as far as SD, THD, and efficiency, and you get some directivity control, too.
> 
> I guess the better attack time of the Neo8s makes sense given the almost zero response/decay time. However, was that with the 12k peakiness completely removed on-axis? I've found that it can give a false impression of speed and detail if not fully removed, even if run off-axis, some reflections still have it. Could try giving the Faitals a big bump at 12k and see what happens.
> 
> ...


One of the ideas I had was to use the MS8 for a line array as an amp/processor combo. When you start adding a lot of drivers to the array, like 8, the top speaker might be hella far from the bottom requiring you do pay more attention to time alignment discrepancies. The output and frequency response could also differ a bit. 

You can use 2 processors. One will run your 5.1. The other will run your line array. At 8channels with amplification the MS8 can EQ, TA, and gain match every driver in your line array. I think either 4 per side or 8 per side can be run off one MS8 very nicely. Otherwise, the more the better. THD seems to fall every time one driver gets added on. This will be particularly important near the HP at say 200hz. 

The 5.1 processor can then feed two channels to the line array, two for the rears, one center, one sub, and have two left over for the midbasses. 

Two processors might sound like a lot of processing but think that you want 5.1 and a line array. It's fairly subtle once you make use of the MS8 amplification. Cuts down one amp! One less amp, one more processor, it's a wash. 

The pillar is going to be chock full of drivers, lined up from top to bottom. I'd go on axis as much as possible and not use a tweeter. Top bottom is not going to really be a choice with 4-8 per side is it? 


All my setups are EQd flat. The neo8 peak wasn't a worry as I use a supertweeter, it's 5 degrees off axis, and EQ.d flat. I think it is the decay. I'm thinking of testing them with a CSD graph next.


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## dbiegel (Oct 15, 2006)

Hmm, neat idea... the MS8 is an 8-channel amp after all  A bit cost-prohibitive for me at the moment... though you make a good point about needing less amps. Hmm.

The neo8 peak can still significantly alter their sound even with a supertweeter. I'm guessing you are not using 72db and above slopes  They'll still have significant output in the 12k region. I'm finding it's very important to EQ drivers well beyond their crossover points, not just in their passband. In this case, the 12k peak can be desirable (sense of detail) -- but it's important to consider its lingering effect if comparing drivers.

The Auras I'm using are only 1.5" square, so I wonder if I can somehow arrange them in a circular arc or something such that there's some "natural" time alignment, at least to some extent... There's enough room to choose top or bottom, because if I use, say, 4 of them, that's only 6" in total array length.


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## fish (Jun 30, 2007)

dbiegel said:


> The Auras I'm using are only 1.5" square, so I wonder if I can somehow arrange them in a circular arc or something such that there's some "natural" time alignment, at least to some extent... There's enough room to choose top or bottom, because if I use, say, 4 of them, that's only 6" in total array length.


Yeah, Lycan talked about the use of an arc (called it "Lycan's Arc") using 3 of the same drivers somewhere on this board.


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## cvjoint (Mar 10, 2006)

dbiegel said:


> Hmm, neat idea... the MS8 is an 8-channel amp after all  A bit cost-prohibitive for me at the moment... though you make a good point about needing less amps. Hmm.
> 
> The neo8 peak can still significantly alter their sound even with a supertweeter. I'm guessing you are not using 72db and above slopes  They'll still have significant output in the 12k region. I'm finding it's very important to EQ drivers well beyond their crossover points, not just in their passband. In this case, the 12k peak can be desirable (sense of detail) -- but it's important to consider its lingering effect if comparing drivers.
> 
> The Auras I'm using are only 1.5" square, so I wonder if I can somehow arrange them in a circular arc or something such that there's some "natural" time alignment, at least to some extent... There's enough room to choose top or bottom, because if I use, say, 4 of them, that's only 6" in total array length.


I think if you have the right source you can get the MS8 at $450 dollars, it also sold for that much as a hot deal not too long ago so there may be many used ones floating around. That's just speculation on my part though. You can start with an 8 channel amp and then convert it to an MS8 for added tuning. My guess is that an 8 channel amp will be two 4 channels amps and cost roughly as much as an MS8. See my point? 

On the Neo 8, depends on what you mean by altering sound. Is it just the amplitude? Yes, it will still prevail after my crossover is set but then I still EQ. the final response. Believe it or not the P99 does not EQ. each speaker individually, just L, R separately. Major drawback for an "ultimate" deck eh? A peak might also/or always is? a resonance. That I cannot eq. This is why I'm turning to CSD lessons next. 

There is such a thing as a natural time alignment. You can build a fake pillar slopping opposite of the one that comes with your car. Post pics!


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## Ultimateherts (Nov 13, 2006)

What if you built an array the length of the dash? In my Equinox there is a space right below where the windshield meets the dash going all the way across. Could I build a small wedge and have say a BG NEO8's or NEO10's going across there?


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## cvjoint (Mar 10, 2006)

Horizontal line arrays have different properties that vertical line arrays. Because our ears are mounted on the sides of our heads the vertical line arrays are a better fit. There would also be more stage width with a vertical line array. With a continuous horizontal line array L,R signals are almost indistinguishable. Might as well grab a large BG planar like RD40 and lay it on the dash in mono.


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## Ultimateherts (Nov 13, 2006)

cvjoint said:


> Horizontal line arrays have different properties that vertical line arrays. Because our ears are mounted on the sides of our heads the vertical line arrays are a better fit. There would also be more stage width with a vertical line array. With a continuous horizontal line array L,R signals are almost indistinguishable. Might as well grab a large BG planar like RD40 and lay it on the dash in mono.


That would seem to make sense. I would think you might be able to use the windshield to reflect a lot of that to get it to sound however you wanted? See the problem I have with vertical arrays is that there is not enough space on the apillar to do anything decent. I like what you are currently doing though... Kepp us posted.


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## cvjoint (Mar 10, 2006)

Thats where the Honda S2000 shines. The pillars are extra wide to maintain rigidity in case of a rollover. Well to be fair even if i had narrower pillar speakers I wouldnt uncover more widshield area. I have nothing to lose, lol, not really a gain.


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## Ultimateherts (Nov 13, 2006)

cajunner said:


> at first, I dismissed the idea of horizontal arrays across the dash as simply a misunderstanding of dispersal plots, and line array positives.
> 
> but then, I started to think about that B&O car with the 62 drivers all around, and I started to think about the Bose 3-2-1 system for home theater, and then the MS-8, and I think it could work!
> 
> ...


From the BG Neo10 specs they can play down to 150hz with an enclosure of around .07 or so which gave me the wedge idea. I think given how far digital eq's, time alignment, and software have come we might be on to something. The only problem I have is powering everything because I still have my stock alt and battery.


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## cvjoint (Mar 10, 2006)

cajunner said:


> at first, I dismissed the idea of horizontal arrays across the dash as simply a misunderstanding of dispersal plots, and line array positives.
> 
> but then, I started to think about that B&O car with the 62 drivers all around, and I started to think about the Bose 3-2-1 system for home theater, and then the MS-8, and I think it could work!
> 
> ...


The whole point of having discrete 2.1 or 5.1 is to get better separation and stage recreation. If a "seamless" blend of drivers would be ideal then everybody would use a beefy center channel, 1.0 and call it a day. Point: distinct left only and right only material is good. I think Ultimateherts got it right. You can use a neo10 on each side. Lay it flat, fire it towards the windshield, and install them as far apart as possible, touching the pillars.


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## Ultimateherts (Nov 13, 2006)

What I actually had in mind was kind of mirroring what both of you are saying. Depending on the length of the actual dash and vehicle you could run either three going all the way across the dash or two separated for a left right traditional setup. Either way I think it could have a lot of potential


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## BowDown (Sep 24, 2009)

Wow this thread has definitely taken a different turn. Is it Audi that's doing the 32 speaker line array?


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## SSSnake (Mar 8, 2007)

> At 8channels with amplification the MS8 can EQ, TA, and gain match every driver in your line array.


How would you set up the MS-8 to do this? In the setup menu you have to tell the MS-8 the mapping of the speakers (FL, FR, SL, SR, etc). All of these, I assume would be front something. The the only choices are one way, two way, etc...

I guess with Logic 7 off you could setup one side as F,S,R and get away with it but I am not sure how you would address 4 or more drivers per side with EQ and TA on each.


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## cvjoint (Mar 10, 2006)

SSSnake said:


> How would you set up the MS-8 to do this? In the setup menu you have to tell the MS-8 the mapping of the speakers (FL, FR, SL, SR, etc). All of these, I assume would be front something. The the only choices are one way, two way, etc...
> 
> I guess with Logic 7 off you could setup one side as F,S,R and get away with it but I am not sure how you would address 4 or more drivers per side with EQ and TA on each.


You mean you can't bypass the fancy algorithms on it? I never owned one but I imagined you don't have to use logic 7 on it. Whoever does try this has to make sure that all 8 channels can be used for midrange duty with no fancy programing lol. 

Another idea of course is to use amplifiers with build in DSP. Here you have to make sure they can do TA, very few do. No matter how you approach the problem, MS8 or dsp amp make note that you are using at least one more additional DA conversion or maybe two. So to get more flexibility and tune each individually you are also degrading the sound in a way. 

For those of you that can fit a BG Neo 10 in whichever configuration use singles. That driver is so bad ass you don't need to use them in multiples. I find the BG larger units like the 8 and 10 to be direct competitors to line arrays not cadidates. They already have the large rectangular frame and come with the low THD and high sensitivity. You would need an army of cougars or what have you smallish cone to equivalate a Neo 10. You may also need to bridge a 4 channel amp on a pair to give it enough power. It's stout in singles.


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## cvjoint (Mar 10, 2006)

cajunner said:


> the way I understand it, line arrays act as one unit.
> 
> using a line array in a horizontal positioning, will create a narrow band of focus up and down, and nothing to the sides.
> 
> ...


We are fooling the brain into thinking a bunch of drivers are one. We can do this more convincingly when the drivers are in a vertical array rather than an horizontal one. Also keep in mind we are in nearfield. The wolf man has a good post somewhere on this site about it and it all comes from where our ears are placed on our heads.

Even on the topic of dispersion, 
1. is the bottom of the windshiled ear level to you or to most of us? If that were true we could hardly see where we are going
2. wide horizontal stage > wide vertical stage
3. the windshield is not god's gift to man. It's not a perfect waveguide but for some reason everybody assumes it is. Can you predict at all what the response is when you get both direct sound and indirect bounced off an irregular object? If you have 7 bands of parametric EQ, wouldn't you want to use them for the midrange where you will always need them versus on the top two octaves where you can get away without it on-axis?
4. comb filtering is in my experience inaudible. I have no doubt it exists, but it seems to be visible only in unsmoothed graphs, or at least less than 1/24 oct smoothed. I would think in extreme cases it would sound like a decrease in sensitivity in the top octave.


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## thehatedguy (May 4, 2007)

A 4 Cougar array would only have the Sd of a single 3" speaker. You would have a little better efficiency that your typical 3" wideband driver. But you would start to run into comb filtering and the other array problems when your array exceeds 2 speakers.


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## cvjoint (Mar 10, 2006)

thehatedguy said:


> A 4 Cougar array would only have the Sd of a single 3" speaker. You would have a little better efficiency that your typical 3" wideband driver. But you would start to run into comb filtering and the other array problems when your array exceeds 2 speakers.


Amazing how hard it is to gather up surface area. I was looking at how many Aura drivers would take to equal the surface area of my dual 4":

10 whispers
24 cougars 

Either way that's a two feet long line array Lol I'm sure they would have a combined higher sensitivity by then but the FS is still high so the low end sensitivity is still low. Then the actual xmax on a very small driver can't be as good either so the surface area doesn't move as much. 

Given the length of a standard pillar in a car I'd say only 2"+ drivers are worth going for. Otherwise you can simply cross your midbass drivers higher and get lower distortion.


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## thehatedguy (May 4, 2007)

But it's not a horn.

Keele has a real nice paper on Bessel Arrays in which he talks about other array properties. 

IF you really wanted to get really trick with an array in a car, I would start reading up on Keele's Constant Beamwidth Array (CBT). He is using the floor bounce to mirror image the top half of an arced array.

I mean where would we find something highly reflective like a concrete or wood floor up high in the car?

Here is Keele's website which has links to his AES papers: http://www.xlrtechs.com/dbkeele.com/CBT.php


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## cvjoint (Mar 10, 2006)

cajunner said:


> Don't forget what Fulcrum Acoustics does with DSP, that's where the meat of this design is.
> 
> Temporal Equalization, check it out.
> 
> Fulcrum Acoustic: Technologies


So I read their tech page and it says absolutely nothing. The pdf? The same, nothing. If you know how their DSP actually works I'm open to hearing about it. 



thehatedguy said:


> But it's not a horn.
> 
> Keele has a real nice paper on Bessel Arrays in which he talks about other array properties.
> 
> ...


This is cool. I was wondering why the newer line arrays in HT are starting to curb like a sunflower. 

Implementing this idea in a car is...well, not possible. You would have to start with a really flat dash. Mount the line array where the windshield meets the dash, then build the arc extending out from the car!


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## dbiegel (Oct 15, 2006)

Guys, check this out... posted about it before, but noone really caught it:

US Patent 7343020 - Vehicle audio system with directional sound and reflected audio imaging for creating a personal sound stage

I think you guys would find it particularly interesting.

I've thought about trying this, but I don't have the advanced fabrication skills to make this look good on my dash. Trying to keep my car OEM. But this looks like a really neat potential paradigm shift for car audio.


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## cvjoint (Mar 10, 2006)

Lolzers. "A reduction in crosstalk", understatement of the century. There is hardly enough reduction in crosstalk to make this work. The planars would have to be a tiny strip of ribbon. How in the world would you get low end extension then? In fact anything under 200hz would still have to use conventional technology, and would be omnidirectional. How did she get a patent on this?


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## cvjoint (Mar 10, 2006)

I tested mine quite a lot for vertical dispersion, it's still pretty good. When you throw 4 nearly touching eachother in a car you are going to get a boatload of crosstalk. This is going to sound like ass, no doubt about it. Don't believe my findings, fine. Look up Zaph's tests on the Neo10, they are sitting on his blog. Look at those vertical FR plots and tell me this patent would work. 

You are going to get only one of the following:
1. limited cross talk
2. low crosspoint

Why? because to reduce vertical dispersion you will have to make a very thin planar element. You can't make it too long or it won't fit in the car, especially when you want 4 of them on the dash. The surface area is bound to be very limited. This will prevent you from crossing low.

Either way you won't be able to cross under 200hz, so this won't work as it will require conventional technology at some point.


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## bassfromspace (Jun 28, 2016)

Considering the size of the BG Neo 10, are you suggesting they be mounted in the pillars?


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## thehatedguy (May 4, 2007)

I see what you are saying. I seem to remember reading something about this...but I swear I can't remember the name for it. That was way back in my 2 channel only days and before I was shown the light of multichannel audio.


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## cvjoint (Mar 10, 2006)

DSP steering? Link?


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## SSSnake (Mar 8, 2007)

> imagine the wall of sound coming from 24 1" drivers that span the dash, using the gain from a quasi-horn loading


I am unsure of the amount of horn loading gain you will get in this situation. The throat of a horn is critical to ensure the proper coupling of the cone to the atmosphere. It is this coupling and the gradual flare to the open atmosphere that provides the gain for a horn. The throat in this situation would be MUCH larger than the SD of the cone. In this situation I don't see a lot of gain from a classic horn loading situation. I do see a lot of gain from reflections. But we all know that this type of gain is typically detrimental to acheiving smooth FR and quality sound.

Take a look at some of Patrick's posts for dash mounted horns. All of the throat entry areas were at SD or less. Where I think he rean into problems (IMO) is where he terminated the mouth into the dash because he had a large discontinutiy in the flare rate in the horizontal axis (which BTW is unavoidable without a dash rebuild or giving up substantial viewing area from the windshield).


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## Ultimateherts (Nov 13, 2006)

SSSnake said:


> I am unsure of the amount of horn loading gain you will get in this situation. The throat of a horn is critical to ensure the proper coupling of the cone to the atmosphere. It is this coupling and the gradual flare to the open atmosphere that provides the gain for a horn. The throat in this situation would be MUCH larger than the SD of the cone. In this situation I don't see a lot of gain from a classic horn loading situation. I do see a lot of gain from reflections. But we all know that this type of gain is typically detrimental to acheiving smooth FR and quality sound.
> 
> Take a look at some of Patrick's posts for dash mounted horns. All of the throat entry areas were at SD or less. Where I think he rean into problems (IMO) is where he terminated the mouth into the dash because he had a large discontinutiy in the flare rate in the horizontal axis (which BTW is unavoidable without a dash rebuild or giving up substantial viewing area from the windshield).


I totally get what your saying about throat size. However, I feel that planars in general give a totally different sound and require such a smaller enclosure size that you could possibly get away with a smaller throat size. Again what makes me think it could work in my Equinox might not work in other vehicles.


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## SSSnake (Mar 8, 2007)

Planars a definitely different animals... My comments were primarily directed toward Cajunner's 24 1" driver approach. I believe the wider the driver (because of the width of the windshield that is forming part of the horn) the better the coupling would be. Planars mounted horizontally would likely - IMO - benefit from greater horn loading than an array of smaller drivers each driven individually.


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## dbiegel (Oct 15, 2006)

One possibility would be to create a "divider" or acoustic lens on the dash to help reduce crosstalk and dispersion between left and right. In other words, create an obstacle between the driver's side speakers and the passenger's head and vice versa.

If the array is only 1.5" wide, that shouldn't be too hard to incorporate, especially if you build a horn lens anyway as cajunner suggested.


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## dbiegel (Oct 15, 2006)

cvjoint said:


> I tested mine quite a lot for vertical dispersion, it's still pretty good. When you throw 4 nearly touching eachother in a car you are going to get a boatload of crosstalk. This is going to sound like ass, no doubt about it. Don't believe my findings, fine. Look up Zaph's tests on the Neo10, they are sitting on his blog. Look at those vertical FR plots and tell me this patent would work.


That's true, but perhaps only because the dimensions of the Neo10 and Neo8 aren't radical enough. A 10x5" planar will have very different ratio of horizontal to vertical dispersion than a 10x1" array.

Also see my comment about the divider/acoustic lens idea above. It doesn't need to be perfect -- just to drop the relative SPL low enough.



> You are going to get only one of the following:
> 1. limited cross talk
> 2. low crosspoint
> 
> ...


Well, depends on the drivers. For example, I have a pair of Audience A3's that are 3" fullranges. Supposedly, they can play down to 50hz (or lower with cabin gain) in an array with extremely low distortion. But then, you're faced with less directivity control over a 1" driver... so you run into other problems. Plus, 16 of them would be unbelievable expensive. Tradeoffs...

Even if we can only get this to work down to 200hz, that's pretty good IMO. The concept might be worth trying.

Another idea for controlling under 200hz -- maybe arranging/tuning midbass drivers such that there's a phase cancellation on-axis of the ones from the other side. So you only hear the appropriate one.


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## thehatedguy (May 4, 2007)

At best with the windshield/dash thing, you would have some sort of conical horn forming. Conical horns by nature do not load anywhere near the Fo of the horn. There isn't enough "squish" at the beginning of the throat, in a conical there is no "squish" there. It is the "squish" area that loads the driver and provides lowend gain (like SSSnake previously mentioned). So any frequencies below say 3x of the Fo of the horn would be direct radiating into the atmosphere- look for example the old Altec A7 bass cabinets where below 300 hertz shot straight through the horn and above was horn loaded.

Then you need to deal with reactance nulling since we are dealing with cone drivers. You would need to make the backchamber for the driver impedance peak match that of the Fo of the horn to allow the drivers to load properly in the horn.

It's just more complicated than throwing speakers on the dash between the windshield and dash and saying, "Yeap, I get horn loading."


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## thehatedguy (May 4, 2007)

On a side note about the horizontal amplitude panning and the array across the dash...I have heard from a couple of people that this is exactly what Mark Elridge has going on in his NASCAR. Is it true? I dunno, never saw behind the grill. But that is the popular rumor about his front stage.


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## chefhow (Apr 29, 2007)

cajunner said:


> imagine the wall of sound coming from 24 1" drivers that span the dash, using the gain from a quasi-horn loading, coupling, and 6 separate amplifiers running 200 hz to 20K, DSP corrected to display a stage that fills the windshield with an image of a depth and coherence previously unattainable through conventional A-pillar or dash cone means..


Didnt Audi try this in the 67 speaker B&O system they had? IIRC it circled the vehicle with 2" speakers, dont remember the exact details but it sounds like what you are describing on a much grander scale.


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## subwoofery (Nov 9, 2008)

chefhow said:


> Didnt Audi try this in the 67 speaker B&O system they had? IIRC it circled the vehicle with 2" speakers, dont remember the exact details but it sounds like what you are describing on a much grander scale.


62 Speakers In Audi’s Sound Concept project » Young man Blog 

Kelvin


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## chefhow (Apr 29, 2007)

cajunner said:


> yes, that is why I say it's sort of like the front section of a 9.2 system, Dolby Digital EXXXX or whatever..
> 
> there would need to be something coming from the sides, from behind, full ambience treatment, I would think to provide the immersive solution that surround sound is dedicated towards.
> 
> ...


I dont see that being all that hard personally. Have you ever been in a vehicle that had horns set up badly? It sounds like 2 seperate stages engulfing you within the front seats, one for the driver and one for the passenger and that was 15 years ago. The real trick would be to extend the stage out 5 ft to the front of the car and as wide as the vehicle. That is where stuff gets crazy.


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## chefhow (Apr 29, 2007)

I would still take a larger whole/complete car effect over a personal one, but that is just the way I would see it working.


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## thehatedguy (May 4, 2007)

If there is no compression of the initial wave front, then there is no low frequency (relative to the horn in question) boosting. Waveguides have no compression, no "squish" area if you will, and thus don't offer any acoustical gain only pattern control.

I mean you could make a large diffraction slot to transition from the speaker to the dash and windshield, but then you have a massive discontinuity in the horn.

And then you have to (or should) think about pattern control since we are doing a waveguide or a horn. How would would do such a thing using the glass and dash without making something come out on to the glass of the car? That is unless you used some sort of amplitude panning. But at that point what are you gaining by doing a waveguide? You use a waveguide to provide directionality and a horn to provide gain...which you wouldn't need the first and aren't getting the second.


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## cvjoint (Mar 10, 2006)

cajunner said:


> DSP can do things today that are limited only by imagination, with this windshield designed front stage you can probably access directional zones from above built into the headliner to encapsulate each passenger in their own personal sound field.
> 
> now that's where the stuff gets crazy...


Imagination yes, also most memeber's combined total savings, actual lifes etc. I built a carputer over ohhh maybe half a year. In the end it could do some neat tricks, 64 band parametric, 100db slopes and linear phase filters. Even then some things that were coded in didn't work well, like the brick filters had a noticeable drum beat to them, some coding was custom to make it all work together etc. 

That was maybe 1 millionth of the technology that is invested in the Audi. With the first try more than a century ago, 5 years of work by qualified engineers etc. My dual 2.5ghz was running at 25% duty just for minimum phase distortion filters. Forget about linear phase filters, I could only run it on 2 or 3 channels out of 8 before the cpu would max out. Then you have to cool it, and in So.Cal. and many other places around the work it's no easy feat. 

I think you are taking this too lightly. The challenges are monumental. Then when it's all done you have to use a jacked up algorithm that converts 2.0 sound into wave form. If the alogorithm is crap, as it usually is, all breaks down. This format is never going to be popular because it takes major investment. Movie theaters wouldn't do it. Personal HT? Yeah right, very few even went up from 5.1 to 7.1. 

Then we need to satisfy basic requirements like SPL and low THD. It seems to me that each one of those speakers are small wide bandwidth drivers. What is their answer? Fiberglass cones...wow. All that to hinge an argument on cone materials.


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## Ultimateherts (Nov 13, 2006)

I still think 2 - 2.5" drivers are pretty sh1tty no matter how many of them there are. Just look at the Tymphany LAT!!! At some point you need larger cone area per driver to actually get a low enough usable FS. If each 2 -2.5" driver can only play down to 800hz then you are screwed from the get go.


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## SSSnake (Mar 8, 2007)

Well as the owner of some Tymphany LAT subs I would take exception to the comment. They do very well in IB or large boxes. If you are referring to the mids they did alright. Not my cup of tea but I can see how they could be utilized effectively.


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## cvjoint (Mar 10, 2006)

There is no clear line on what works and what doesn't. For example, there are an enormous amount of cars with single 3" mids. Would never work for me but with the right material, in the right low noise car, for someone that loves to listen at low levels I'm sure they are splendid. Different strokes for different folks. 

One thing that was expected but still amazed me was how THD dropped when I added a second driver. Whether you need the high output or not there is no doubt adding more drivers will reduce nonlinear distortion. I know SPL is often frowned upon on an esque site like this but low distortion and output almost always go hand in hand.


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## Ultimateherts (Nov 13, 2006)

cajunner said:


> you can go a lot lower than 800 hz with a 1.5" driver...
> 
> have you ever heard an Aura Whisper?
> 
> those things are amazing, I was a skeptic too until a pair came in and made me re-think some of the "tweeter" comments.


Still though cone area is the name of the game.


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## omegaslast (Nov 4, 2010)

cvjoint said:


> There is no clear line on what works and what doesn't. For example, there are an enormous amount of cars with single 3" mids. Would never work for me but with the right material, in the right low noise car, for someone that loves to listen at low levels I'm sure they are splendid. Different strokes for different folks.
> 
> One thing that was expected but still amazed me was how THD dropped when I added a second driver. Whether you need the high output or not there is no doubt adding more drivers will reduce nonlinear distortion. I know SPL is often frowned upon on an esque site like this but low distortion and output almost always go hand in hand.


I have REW with a dayton xlr mic... any way to run HD measurements on my LS6? not sure how you actually measure a line source though.


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## cvjoint (Mar 10, 2006)

omegaslast said:


> I have REW with a dayton xlr mic... any way to run HD measurements on my LS6? not sure how you actually measure a line source though.


Hey, you figured how to use REW, you can do it! Haha, well it depends on what you want. If you want to test the Ls6 itself you need to mount it on a big plywood board. Secure it etc. I just take measurements at the listening position for the overall performance. Swapping drivers in the same pod does keep a lot of variables fixed though. I imagine you can't do really close measurements with a line array, everthying else should be the same.


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## thehatedguy (May 4, 2007)

cajunner-

A Paul Kemble web page - speaker bessel arrays.

You might find something interesting in those arrays.


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## Ultimateherts (Nov 13, 2006)

thehatedguy said:


> cajunner-
> 
> A Paul Kemble web page - speaker bessel arrays.
> 
> You might find something interesting in those arrays.



Great find!


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## Golden Ears (Jul 18, 2010)

Thigpen was a planar magnetic guy.. he made speakers that had a driver similar to infinity systems EMIM midrange... The EMIM was used in the greatest home loudspeaker system made in the 1980's- 1990's The Infinity IRS I,II,III, and V (There was no 4 as four is considered unlucky in some Asian cultures like the number 13 in western cultures). This was HP's reference for many years at Seacliff NY (He is the editor of TAS - The Abso!ute Sound)

In keeping with the OP's desires...

The LFT-10 Planar Magnetic Car Loudspeaker

http://www.eminent-tech.com/randd2.html

Personally..I think what you are trying to do is compensate for the rake angle of the A Pillar..

to which I would say.. how about trying a car with a pretty straight a-pillar

like 
Mercedes-Benz W108 - Wikipedia, the free encyclopedia

and just tilting your seat back a bit to match that angle?

Also I have worked with many planar speakers and I can say confidently- that the time response of the speakers is smeared...when you do not have a planar surface to relect off of. 

Planar means FLAT. Not curved like a windshield.. I have tried reflecting home planars off of curved reflective surfaces..and it just makes them tonally sound wrong...smeared.

I even have issues with reflecting off a wall- and partially reflecting off of a sliding glass door which is recessed about 2.5 inches into the reflecting wall.. yes even small windows mess up the reflection.

I did, however at one time, want good sound in a convertible and I thought... well...why not have planar magnetics in a second layer of Sun Visors and ...gasp (as in ugly) ... in order to slow down the air buffetting when driving- you would cover them with a furry material (like you do for an outdoor boom Microphone on a camera to reduce wind noise - by reducing wind speed at the transducer)


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## cvjoint (Mar 10, 2006)

Indeed his other patents look better. I'm still not buying the patent quoted here. The shape of his planar tells me he will have very good dispersion vertically and horizontally. Then it still doesn't cover frequencies lower than 400hz. 

Cool stuff though, good read. I lol'ed at the Mercedes. Those pillars look like mine angle wise. I think most small sports cars have a straighter profile which helps. I would think you would link a VW bus or Beetle.

Could you go more in detail about smearing? Why would reflection be needed? 

"Sorry officer, I didn't see you braking in front of me because I angled my seat to match the rake of pillar." Wouldn't hold in court!


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## Golden Ears (Jul 18, 2010)

cvjoint said:


> ...snipped...I would think you would link a VW bus or Beetle.


Yes a VW bus would be much better.


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## Golden Ears (Jul 18, 2010)

The other possibility... though wild as it may seem... would be doing something very strange.

Either create a second windshield layer which is vertical- you'd need a second defroster vent too... and use panel exciters on it. The amount of surface area would allow for lower bass than with most car audio solutions... maybe low enough to a subwoofer range.


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## Ultimateherts (Nov 13, 2006)

Golden Ears said:


> you'd need a second defroster vent too


Actually in my Equinox maybe not. I know the BG NEO10 will not fit like I had planed, but the NEO8 is a definate possibility. I will take some measurements tonight and post later on.


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## Ultimateherts (Nov 13, 2006)

Ok so I just measured the dash:

Length: 51.5"

Width: 3.5"

Height: 3.75"

So it looks like the NEO10 is a no go, but the NEO8 would just fit in. Around (6) of them would fit going all the way across.


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## fish (Jun 30, 2007)

Ultimateherts said:


> Ok so I just measured the dash:
> 
> Length: 51.5"
> 
> ...


If you did this would you implement a "wall" in between the two in the center?


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## Golden Ears (Jul 18, 2010)

A wall between the left and right would keep the left ear from hearing the right channel. Akin to the problems with headphones...likely better with Binaural recordings- but the head acts as a filter and the ear must hear the opposing speaker and the corresponding inter-aural delay with the theoretical filter caused by the mass of the head. Of course ....if the sound engineer had a fat head and you have a skinny bony one...YMMV... perhaps that is why I don't get Wes Phillips recordings.


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## fish (Jun 30, 2007)

I don't know, it just seems like it would sound like it was in mono set up like that without a partition.


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## Ultimateherts (Nov 13, 2006)

fish said:


> If you did this would you implement a "wall" in between the two in the center?


A wall could be done, however I would most likely run all in the same as one big single enclosure. My only concern would be the effect it might have...


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## Yepvegas (Sep 23, 2009)

Now this thread has been a interesting read. Anyone going to build it?


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## subwoofery (Nov 9, 2008)

Yepvegas said:


> Now this thread has been a interesting read. Anyone going to build it?


It has been done already... do a search 

Kelvin


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## Yepvegas (Sep 23, 2009)

Ok I have looked and have not found a Horizontal Line Array installed. Any chance could point me in the right direction.?


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## Ultimateherts (Nov 13, 2006)

Yepvegas said:


> Ok I have looked and have not found a Horizontal Line Array installed. Any chance could point me in the right direction.?


~Aura Whispers would be a good starting point~


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## Yepvegas (Sep 23, 2009)

I will look into it. I did find a build but the car was scrapped literally and was not finished. He had drivers spanning the entire dash.


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## Oliver (Jun 25, 2007)

Ultimateherts said:


> Great find!


 read this


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## alm001 (Feb 13, 2010)

I'll bump this thread to whore my partial array.
http://www.diymobileaudio.com/forum/build-logs-project-install-gallery/106593-2001-audi-s4.html
44mm CTC spacing, current crossover has them playing down to about 2500
My initial (negative)impression was the day after Aoki live. Since my hearing has recovered - the sound is amazing.


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## Ultimateherts (Nov 13, 2006)

What about using the Tang Band 3" sub? I know the depth isn't that great to work with, but at $29 each they would be easy enough on the wallet!!!


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## Ultimateherts (Nov 13, 2006)

O.k I decided to revive this thread because it relates to my current install process involving PVC piping:

http://www.diymobileaudio.com/forum/fabrication-tools-tricks-trade/123614-pvc-piping-dash.html

I was at HOME DEPOT trying to find a 3" to 1.50" coupler and I noticed they had dual and even tri 1.5" couplers. I already have laid out the PVC piping to where it fits the legnth of the dash and extends to right out to where the driver's and passenger's side apillars are located. 

However, if one wanted to run 3" midbasses across the entire dash all they would need to do is follow what I did with running the PVC piping. Except they would have splits in sections so that they could use the tri 1.5" coupler followed by three 3" to 1.5" couplers.

Here is a crude quick sketch I drew up:


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> But it's not a horn.
> 
> Keele has a real nice paper on Bessel Arrays in which he talks about other array properties.
> 
> ...


The CBT is quite interesting. Here's a thread I'm working on, with the math and some sims on doing a CBT array, along with comparisons to a conventional line array and one of the power-tapered Griffin arrays:

Audio Psychosis • View topic - An Array That Does Not Suck?


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