[FredT300B]

Welcome to the Line Array speakers circle. For those who are unfamiliar with line array speakers, a line array is is a group of drivers arrayed in a straight line, closely spaced and operating in phase. While that's a good technical explanation it doesn't begin to describe the "soul" of a pair of well designed line arrays in your listening room. It's one of those "you have to be there" things. The first time you hear line arrays will be an epiphany, and it will be hard to go back to point source speakers.

The focus of this circle is "nearfield" line arrays used in home audio, which are different from the "farfield" professional line arrays used for sound reinforcement in large public places like auditoriums and churches. We'll be discussing all the line arrays that are available for home audio use, ranging from the mainstream arrays like the Pipedreams, Epiphanies  and McIntoshes, through the more affordable arrays offered in kit form or completely assembled through direct internet sale by companies like GR Research, Selah Audio, AV123, and others. We'll also discuss DIY line arrays, including the low budget arrays that are being built by many DIY speaker builders, often for less than $250/pr using "buyout" drivers.

The technology of line arrays is complex, and I'm hoping the Audio Circles' regular line array expert posters, including Danny Ritchie, Rick Craig, and Dr Jim Griffin, will help guide us all toward a better understanding of this remarkable speaker type.

It's customary in the first post of a new circle's facilitator to remind everybody to observe the rules of the forum. OK, you are reminded, and there's one that's especially important. I expect everybody to get at least a B- on their report card each semester under "Works and plays well with others". Participants who are commercially involved in line array speaker design are held to an even higher standard, and they are expected to consistently get A's.

So let the fun begin!

[JohnR]

Awesome 

Thanks Fred!

[TheChairGuy]

Very, very cool - hiya' Fred, and thanks for hosting 

[JohninCR]

Great idea for a circle.  While so much time at AC is spent discussing the subtle differences of things like cables, amps and tweaks, line arrays (LA's) are even more different sounding from typical point source speakers than open baffles are from boxed speakers.  A properly designed LA is something special indeed.  To me a good point source speaker brings the performance into your room, but an LA transports you to the actual event.  Like OB's, LA's offer some unique in-room behavior advantages that help take the room out of the equation.

I hope the discussions will not be restricted to only LA's, but will also include true line sources such as long ribbon speakers, since LA's only approximate the behavior of a line source.  Having not heard a true line source, I'd be especially interested in comments about direct comparisons from those who have heard both.

In any event, I believe that Dr. Griffin's work, that he's so graciously shared with the online community, is a must read for anyone interested in LA's.  It's not only important for those wanting to build their own, but it will help those purchasing speakers identify a proper design, since a number of multi-driver speakers are marketed as "line arrays", but the physics prevents much meaningful line source behavior.  One of those "must reads" is here:
http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

[S Clark]

Fred, you couldn't have started this forum at a better time.  This year I plan on having a group of my high school physics students build a line array as a project.  I have no doubt that this will be an invaluable tool for them (and myself0. Thanks for moderating.

Scott

[lonewolfny42]

Good luck Fred with the new circle.....

                                     Chris

[spudco]

I'm hooked!

If I ever get any $ in by bank account, I will purchase a line array to replace my Dunlavy Vs.

Across the last 4 years, I have heard several arrays and they work for me!

[KCI-JohnP]

Hey Fred,
Cool, glad you got your own circle. As you know I am soon to be a member of the LA club and I'm pretty darn excited about it. I wish I could have them here in time for the meet but alas, maybe next time. I'll be sure to post a pic or two in here when I do get them. Congrats on the circle Fred!!

Regards,
John

[Wardsweb]

Congratulations on your new circle Fred. I can't think of a better person to host this one.

I think Fred has built more different line arrays than anyone that doesn't do it as a business.

It also helps to have a serious wood shop:

[bluesky]

Hi

Congrats to Fred on this circle.  I have two different line arrays ideas which I hpe to start in the next month or so.  Once I've assembled all the drivers and the wood I'll do a post seeking advice on contruction and dimensions etc

Bluesky

[Charivari]

Congrats on the forum Fred!

I hope the discussions will not be restricted to only LA's, but will also include true line sources such as long ribbon speakers, since LA's only approximate the behavior of a line source.  Having not heard a true line source, I'd be especially interested in comments about direct comparisons from those who have heard both.

Same here. My mains are hodge-podged true ribbon and planar-magnetic line sources.

- JP

[John Casler]

Welcome to the Line Array speakers circle. For those who are unfamiliar with line array speakers, a line array is is a group of drivers arrayed in a straight line, closely spaced and operating in phase. So let the fun begin!

I hope the discussions will not be restricted to only LA's, but will also include true line sources such as long ribbon speakers, since LA's only approximate the behavior of a line source.  Having not heard a true line source, I'd be especially interested in comments about direct comparisons from those who have heard both.

Just dropped in to see what this Circle was doing, and found some of the posts very interesting.

While definitions are "only" used for technical understanding, I was wondering about a couple.

It would seem that any drivers (more than one?) arranged in a group are an "array"?

If that group is in a line then it is a "line source"?

Is there any traditional or official designation that all the drivers be of like, size, frequency, output? to be a line source? or a line array?

Is there any specific length in the definition of a "line"?  That is, does it simply have to be longer than wide?, or does it need to be 2:1?, or longer than 6"? or what?

I have a pair of RM40 speakers, and while it is not important that they be qualified or classified as WMTMW, or WLSTLSW or any such, I was wondering if a line of planar panels was generally considered a "line source".

It would seem that you can have dissimilar drivers in "side by side" lines and still be a "line".  Is there any qualification "traditional or official" that a line has to be "unbroken" in the vertical? as in the my personal RM40 example above?

Obviously in understanding the "physics" and Psychoacoustic properties of "lines" it seems that the primary definers are the "wave launch", dispersive/radiation properties, and the the reinforcement of of SPLs by the number of drivers.

[FredT300B]

Just dropped in to see what this Circle was doing, and found some of the posts very interesting.

While definitions are "only" used for technical understanding, I was wondering about a couple.

It would seem that any drivers (more than one?) arranged in a group are an "array"?

If that group is in a line then it is a "line source"?

Is there any traditional or official designation that all the drivers be of like, size, frequency, output? to be a line source? or a line array?

Is there any specific length in the definition of a "line"?  That is, does it simply have to be longer than wide?, or does it need to be 2:1?, or longer than 6"? or what?

John, thanks for stopping by. Those are interesting questions, and one could spend hours debating what is and is not a line array, but my preference is to be inclusive and not establish a restrictive definition.

[samplesj]

Welcome to the Line Array speakers circle. For those who are unfamiliar with line array speakers, a line array is is a group of drivers arrayed in a straight line, closely spaced and operating in phase. So let the fun begin!

I hope the discussions will not be restricted to only LA's, but will also include true line sources such as long ribbon speakers, since LA's only approximate the behavior of a line source.  Having not heard a true line source, I'd be especially interested in comments about direct comparisons from those who have heard both.

Just dropped in to see what this Circle was doing, and found some of the posts very interesting.

While definitions are "only" used for technical understanding, I was wondering about a couple.

It would seem that any drivers (more than one?) arranged in a group are an "array"?

If that group is in a line then it is a "line source"?

Is there any traditional or official designation that all the drivers be of like, size, frequency, output? to be a line source? or a line array?

Is there any specific length in the definition of a "line"?  That is, does it simply have to be longer than wide?, or does it need to be 2:1?, or longer than 6"? or what?

I have a pair of RM40 speakers, and while it is not important that they be qualified or classified as WMTMW, or WLSTLSW or any such, I was wondering if a line of planar panels was generally considered a "line source".

It would seem that you can have dissimilar drivers in "side by side" lines and still be a "line".  Is there any qualification "traditional or official" that a line has to be "unbroken" in the vertical? as in the my personal RM40 example above?

Obviously in understanding the "physics" and Psychoacoustic properties of "lines" it seems that the primary definers are the "wave launch", dispersive/radiation properties, and the the reinforcement of of SPLs by the number of drivers.

Please read Dr Griffon's paper.  It answers so many of these questions.

If it isn't a mostly room height line then it isn't a line source.  A line source (or approximation with a line array as JohnInCR points out) isn't just a marketing term to use to sell more speakers.  It has specific dispersion characteristics and can only have those if its "long enough".

As a side effect of that there is NO such thing as a W LS T LS W if you use that to describe vertical layout.  You can't have 2 line sources on top of each other.  Together they are a single line source or neither is.

I find it humorous that last year when I mentioned Dr Griffons paper and asked about ceiling bounce for Maggies you were claiming they weren't line sources, but now want to call the speakers you sell line sources/line arrays.

[Rick Craig]

Welcome to the Line Array speakers circle. For those who are unfamiliar with line array speakers, a line array is is a group of drivers arrayed in a straight line, closely spaced and operating in phase. So let the fun begin!

I hope the discussions will not be restricted to only LA's, but will also include true line sources such as long ribbon speakers, since LA's only approximate the behavior of a line source.  Having not heard a true line source, I'd be especially interested in comments about direct comparisons from those who have heard both.

Just dropped in to see what this Circle was doing, and found some of the posts very interesting.

While definitions are "only" used for technical understanding, I was wondering about a couple.

It would seem that any drivers (more than one?) arranged in a group are an "array"?

If that group is in a line then it is a "line source"?

Is there any traditional or official designation that all the drivers be of like, size, frequency, output? to be a line source? or a line array?

Is there any specific length in the definition of a "line"?  That is, does it simply have to be longer than wide?, or does it need to be 2:1?, or longer than 6"? or what?

I have a pair of RM40 speakers, and while it is not important that they be qualified or classified as WMTMW, or WLSTLSW or any such, I was wondering if a line of planar panels was generally considered a "line source".

It would seem that you can have dissimilar drivers in "side by side" lines and still be a "line".  Is there any qualification "traditional or official" that a line has to be "unbroken" in the vertical? as in the my personal RM40 example above?

Obviously in understanding the "physics" and Psychoacoustic properties of "lines" it seems that the primary definers are the "wave launch", dispersive/radiation properties, and the the reinforcement of of SPLs by the number of drivers.

I would suggest reading Jim Griffin's paper. In my experience having both lines (woofers and tweeters in a 2-way design) 45" or longer works best for a typical home listening room. I've designed "mixed" point source / array systems by customer request but feel they have tradeoffs that make a true line array the better choice.

[John Casler]

John, thanks for stopping by. Those are interesting questions, and one could spend hours debating what is and is not a line array, but my preference is to be inclusive and not establish a restrictive definition.

Hi Fred,

While I have no interest in "designing speakers", I do find "speaker design" interesting.

In general, it seems that classifications are based on dispersion/wave front and launch (Dipole, bipole, Omni-polar, point source, line source, etc) and or, the number, arrangement or types of drivers (line array, single driver, 3-way, 2-way, MTM, WMTMW, TMW, etc)

I occasionally have people ask me what my speakers are, or hear or read of them calling them a particular type.

I was also curious as to the "orientation" of the Line Array.  It would seem that they are always operated "vertically".  Is that a requirement?  If it is placed horizontally does it then become something else?

Jeremy,

You might have me mixed up with someone else on the Maggie comment, or it may have been a communcation mix up.

I wasn't interested in causing a heated debate, since I don't find a "classification" to offer anything except information about what design is used.  I think it is good to try and understand the differences between a line source, and a line array, and or a "mixed array", or Hybrid, if there is such a thing.

A Maggie certainly would be an interesting speaker to discuss, since it would seem to be a continous "line source", and since some have a tweeter and MR/Bass panel, it then is a 2-way.  But is it an "array"?

And while the tweeter panel is a "line source", it seems to act a bit like a "point source", in those frequencies, since you only (to my understanding) hear the portion of that driver at ear level, due to the "qualities of dispersion" of that type of driver.

I have read the Griffin  paper several times, and it seems to speak to what I was asking, and that is, the wave launch and dispersion (as well as the "interaction of multiple drivers).  While it says the perfect LA would continue into infinity, it doesn't set a qualification of length on the shortest end.

Hi Rick,

Thanks for the answer.  I had seen one of your designs, the OmegaRay I think and noticed that it was a 3-way, and I had wondered to myself was it still a LA, or a "hybrid".

[Rick Craig]

John, thanks for stopping by. Those are interesting questions, and one could spend hours debating what is and is not a line array, but my preference is to be inclusive and not establish a restrictive definition.

Hi Fred,

While I have no interest in "designing speakers", I do find "speaker design" interesting.

In general, it seems that classifications are based on dispersion/wave front and launch (Dipole, bipole, Omni-polar, point source, line source, etc) and or, the number, arrangement or types of drivers (line array, single driver, 3-way, 2-way, MTM, WMTMW, TMW, etc)

I occasionally have people ask me what my speakers are, or hear or read of them calling them a particular type.

I was also curious as to the "orientation" of the Line Array.  It would seem that they are always operated "vertically".  Is that a requirement?  If it is placed horizontally does it then become something else?

Jeremy,

You might have me mixed up with someone else on the Maggie comment, or it may have been a communcation mix up.

I wasn't interested in causing a heated debate, since I don't find a "classification" to offer anything except information about what design is used.  I think it is good to try and understand the differences between a line source, and a line array, and or a "mixed array", or Hybrid, if there is such a thing.

A Maggie certainly would be an interesting speaker to discuss, since it would seem to be a continous "line source", and since some have a tweeter and MR/Bass panel, it then is a 2-way.  But is it an "array"?

And while the tweeter panel is a "line source", it seems to act a bit like a "point source", in those frequencies, since you only (to my understanding) hear the portion of that driver at ear level, due to the "qualities of dispersion" of that type of driver.

I have read the Griffin  paper several times, and it seems to speak to what I was asking, and that is, the wave launch and dispersion (as well as the "interaction of multiple drivers).  While it says the perfect LA would continue into infinity, it doesn't set a qualification of length on the shortest end.

Hi Rick,

Thanks for the answer.  I had seen one of your designs, the OmegaRay I think and noticed that it was a 3-way, and I had wondered to myself was it still a LA, or a "hybrid".

The Omegarray was a 2-way with a powered subwoofer at the bottom.

[samplesj]

I was also curious as to the "orientation" of the Line Array.  It would seem that they are always operated "vertically".  Is that a requirement?  If it is placed horizontally does it then become something else

Its all about the dispersion pattern so why not.  I'm sure someone else will chime in if this isn't possible, but keep in mind that a horizontal line source is going to need to be nearly as wide as the room.

Jeremy,

You might have me mixed up with someone else on the Maggie comment, or it may have been a communcation mix up.

I wasn't interested in causing a heated debate, since I don't find a "classification" to offer anything except information about what design is used.  I think it is good to try and understand the differences between a line source, and a line array, and or a "mixed array" or Hybrid if there is such a thing.

A Maggie certainly would be an interesting speaker to discuss, since it would seem to be a continous "line source", and since some have a tweeter and MR/Bass panel it then is an 2-way.  But is it an "array"?

And while the tweeter panel is a "line source", it seems to act a bit like a "point source", in those frequencies, since you only (to my understanding) hear the portion of that driver at ear level, due to the "qualities of dispersion" of that type of driver.

I have read the Griffin  paper several times, and it seems to speak to what I was asking, and that is, the wave launch and dispersion.  While it says the perfect LA would continue into infinity, it doesn't set a qualification of length on the shortest end.

Here is that thread where we talked about maggies and line sources http://www.audiocircle.com/index.php?topic=25489.0

Anyway, the special dispersion pattern is a characteristic of line sources.  Line arrays are one way to simulate that.  You can also use a full size driver (like a maggie).  Maggies are not line arrays, but they are a true line source.  There is a tweeter, midwoofer (on some models), and woofer line source but it isn't a line array.  Griffin's paper even talks about tweeter/woofer line sources.  Multiple line sources doesn't make you an array.

Now there are other advantages to line arrays (multiple drivers can =  efficency for example), but in terms of dispersion they are an approximation of a true line source.  Even Griffin's (sorry for the spelling error before) paper clearly says "The goal in determination of the spacing between drivers in a line array is to position them so that you approximate a continuous line source as closely as possible."

It doesn't matter if a line source/line array only lets you hear a certain part of the ribbon (or only certain drivers).  It is the fact that the sound travels in a cylindrical wave vs a spherical that makes it a line source.

[FredT300B]

This thread is headed away from the original topic, which was simply to introduce the new circle, so I've decided to lock it and start a new thread entitled "Defining a line array?"