JoeESP9
ESL's & tubes since 83
I was trying to point out how large that many 12" speakers are in any kind of alignment.
What’s the buzz with Line Array?
- Thread starter nick parkin
- Start date
I was trying to point out how large that many 12" speakers are in any kind of alignment.
No question. Since first octave bass is non-directional, the value with having an array of woofers is improving power handling and/or sensitivity.
I'd be much more interested in sourcing a large number of smaller 3" drivers like you find with the IDS-25 if you choose the dynamic route. Collectively, they have the area of a single 15" woofer.
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It gives the EMIMs lower response. You'll necessarily need to run the woofer towers at a higher frequency.
Do you know if this design is dipolar with separate drivers on the rear?
Justgotohm
Super Member
I was in a fellow enthusiast home recently that had built these arrays. He currently did not have them hooked up but I very much would like to eventually hear them. The guy next to them is about 5’10” or so I’m guessing.
JoeESP9
ESL's & tubes since 83
You're not the one who called EMIT's and EMIM's ribbon speakers. Many also call the various Heil clones ribbons. They are not ribbons either.
EMIT: Electromagnetic Induction Tweeter
EMIM: Electromagnetic Induction Midrange
Heil (AMT): Air Motion Transformer
With a ribbon the diaphragm is also the voice coil. There is no Mylar or Capton substrate to which a voice coil is added.
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Well, actually I did.
I’m aware of the acronyms, but like Magneplanar considers some of their panel designs quasi-ribbons, the Infinity design shares similarities.
First heard the IRS at Sea Cliff in 1980.
JoeESP9
ESL's & tubes since 83
I've often wondered if Arnie Nudell was influenced by the Magneplanar design. He did go from esl's (Servostatik) to EMIT's and EMIM's while keeping the servo subs.
I'm currently using a pair of Maggies that are "Quasi Ribbon". IMO the Quasi Ribbon thing is an advance and improvement over older Maggies with glued on wires. Yes, I've had both types.
The main panels on old Apogee planars were quasi ribbon. They used flat traces on Capton(?) film. AFAIK their tweeters were actually real ribbons.
I'm currently using a pair of Maggies that are "Quasi Ribbon". IMO the Quasi Ribbon thing is an advance and improvement over older Maggies with glued on wires. Yes, I've had both types.
The main panels on old Apogee planars were quasi ribbon. They used flat traces on Capton(?) film. AFAIK their tweeters were actually real ribbons.
I would think so. Winey's first Tympani came out about the time of the Servo Statik around 1970. And the SS did suffer some reliability issues with the RTR panels, so Nudell was likely looking for an answer. When you read the brochure on the QRS that followed, recall that it used EMIRMs (a true ribbon) along with the recently introduced EMIT. Discussion of both midrange and tweeter compares them to electrostatics in possessing low mass with distributed driving force. And the similarity of the EMIT to a "true" ribbon.
As previously noted, don't forget the ribbon based midrange that preceded the EMIM.
Harry tried those before the IRS was introduced and while he liked the mid and top, he greatly preferred mating the bass panels from the Tympani 1D to them instead of using the cone woofer dubbing them the "QRS-1D". Harry said Arnie visited a number of times and no doubt experienced them. While I never heard the QRS-1D, I suspect I would prefer them to the continued use of cone woofers in terms of coherency. It might be interesting to mate the IRS/Genesis mains with the 30.7s woofers!
Coherency freaks like me find the mating of dipolar panels and monopole woofers extremely difficult to get right unless the xover lies lower than most designs you see. Which is why I'm not a fan of hybrids like most Martin-Logans and the Sanders Sound models which cross right at the top of the bass/lower midrange (170-300 hz). With the HT, I cross the subs to the 1+1s at 60 hz which is still a bit higher than ideal from my viewpoint. I chose that frequency based upon measuring the results and achieving the most linear response in my room.
edit: I remembered it half right. High pass to 1+1s at 60 hz, low pass to subs at 50 hz. Coherency remains quite good.
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Looks kinda like a Pipedreams clone albeit in a three-way design. That's the kind of driver to driver spacing you typically find - none!
twiiii
Lunatic Member
Line arrays or Column speakers have been around for a long time. They handle more power, put out more level with lower distortion and can control off axis emissions, better. The human ear/brain integrates the sound so anomalies created by different very short arrival times don't compromise the sound. Whether the baffle is narrow like a full range IDS or wide and tall like a XR 290 it depends on the choice of drivers, crossover, and layout design as to the success of the design. Really tall designs allow you to stand, sit, lay prone and enjoy the same sound. The longer the array the the less interference from floor and ceilings, vertical off axis energy is reduced. The increased Q or directional coefficient allow the sound to travel further with less loss, too. With a point source speaker the direct sound level drops 6 db every time you double the distance until the reverberant field becomes the dominant sound. The line array is closer 3 db and there for has less output loss. But as the sound is much more directional the reverberant field will have less of an effect and not support the out put level as soon. So there are a lot of variables as to which system will be louder with the same power. But for sure the line array will have a more intimate sound, similar to a horn system, but with out all the resonant horn quality. Line arrays brought very low distortion sound reproduction to our homes using fairly conventional drivers without using todays very expensive cone materials back in the late 70's. Magnepan are bi directional line arrays and the rear emissions can make or break a system depending on what is done with the rear emission. My favorite line array is the XR290, it is tall, but wide, too. It was designed to be used close to a rear surface where the wall and the enclosure became one ultimately wide baffle supporting frequencies in the lower midrange on down, so reflections didn't cause dips in the response, you get when pulling enclosures away from from surfaces. Standing waves are always an issue but the directionality of a line array reduces them in the frequencies produced by the mid and high freq drivers. I don't like to sit right next to speakers, I want space and yet to maintain definition, too. Fortunatly we deal with very short reverberation times which allows us some freedoms in homes to place speakers that can't be used in large spaces. So for the lowest distortion, with high out put and controlled dispersion to reduce room effects you want line arrays. Un fortunately, they are not efficient for consumers, yet, so do require ampled power just like point source speakers.Stack 10 Altec 511or 811 B horns with 802 drivers and make a line array , with 6 515's stacked in a custom column and then bi amp. 106 db 1 watt 4ft with 300 watts for the horns = 130 db, and with the high output 515 that would be 900 watts 101 db ported 4ft or about 130 db. And really as Paul was to have said all you would need would be 10 watts for the horns and I would say about maybe 40 watts for the woofers. Lets see if you used 2 817 enclosures with 4 woofers, That would be 106 db 4 ft1 watt or about 133 db for the woofers and only 10 for the woofers for concert level.. Now buying amps with 124 db signal to noise becomes important. But what do you do for frequencies below 40 HZ where stacked 817 are already rolled off about 3 to 5 db. I know stick them in a corner or for a bit less against a wall. I saw 12, placed in two corners, - 816 enclosures with 421's with an extra gasket to prevent cone from hitting the woofer horn baffle put out 32 hz at 124 db at 100 ft distance at an Altec seminar where Stanel Sound was providing us a presentation of a Neil Diamond concert, featuring "Coming to America" they had recorded live.
If you attend live concerts now days almost everyone uses line arrays. .The Grateful Dead's wall of sound was just a series of line arrays stacked to gether to form a wall. Each instrument had its own dedicated electronics and Mac amp connected to a line array column of mostly Lansing speakers.
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I think Arnie choose not to continue using electrostatic drivers and used his new drivers the EMIM and EMIT's to get away from reliability issues, not to mention cost. With electrostatics you have the high voltage issues as well to contend with. His new drives basically had the positive attributes of an electrostatic ribbon without all any of the associated negative issues all in a neat fairly low cost package, that could be used in a wide range of speaker configurations.
toxcrusadr
Omelette au Fromage
You do get a boost in output with multiple drivers. Two woofers together, for example, gives you an extra 3 db on top of the doubled output from having two drivers, just as a bonus. It's kinda complicated but you get 6 db more acoustic output from only a 3 db (i.e. doubling) of input power. That is, assuming the drivers are in parallel. With line arrays you usually end up with series-parallel grouping so the output have to be calculated. I found a cool little spreadsheet that will calculate overall sensitivity and impedance of an array from the # drivers, driver impedance, driver sensitivity, and overall impedance of the array. It's posted to this thread for anyone who might be thinking about designing a LA.
http://www.htguide.com/forum/showthread.php?27677-Calculating-line-array-sensitivity
http://www.htguide.com/forum/showthread.php?27677-Calculating-line-array-sensitivity
I belive they are dipolar /OB with some rear damping. No rear firing drivers.
Rear photo
Amps are Holton class a monos
Dipole bass towers are under construction
Speakers : DIY Infinity Emim Tower -12dB @200Hz
Bass 2x4x10" sealed
DBX PA: filter for bass
Pre: AVM V-30
Power : Holton 500L and 800R2 monoblocks
Cables : MIT-750, Monster M1
Tidal PC/USB DAC.
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Cool! And now I clearly see the acrylic(?) "wings". Quite interesting design.
I just love the acoustic space dipoles can produce when given the room to breathe. I've never been a fan of speakers slammed against (or put into) a wall. Rule of thirds!
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Actually its real glass, inspired by Toneart Etera. This guy works as a car painter and builds all the stuff himself including the class a amps. The evolution of this set up has been going on for years. Quite interesting build thread, especially regarding implementing of the bass towers and crossover design for the Emims.
And Emits
Thanks for all the information! Great DIY project indeed.
You are a better man than I in terms of managing multiple languages. I was taught French in elementary and high school but with little practical use over the years, my ability is limited. I would love to visit Norway and enjoy the splendor of the Aurora in the winter.
