Project Category:
Tower Speakers

Project Level:

Project Time:
20+ Hours

Project Cost:
$500 – $1,000

Project Description:
Mid sized line array with improved realism vertical image, low distortions and high power handling.
Bass response projected to 80hz.
Relatively small budget for line array, using low distortion buyout Fountek drivers within desirable passband.

Design Goals:
Affordable Line Array sound in a small package.

Driver Selection:



Enclosure Design:
Sealed enclosure for both midrange and woofer sections. Multiple bracing is highly recommended.
Drawings are for 3/4” thick material.

Crossover Design:
Crossover design is fairly straightforward. Tweeter array is represented by a single T1 driver as well as midrange array is represented by M1 driver and woofers, by W1. This is done so the crossover CAD screen is not cluttered with 16 drivers.
Wiring the array.
Tweeters are numbered from the top to the bottom. Top tweeter is #1 and lower tweeter subsequently numbered #5. Tweeters #1,#2, #4 and #5 are wired in series to each other. This quartet is wired parallel to the center tweeter #3.
Midrange drivers.
There’s total of 9 drivers. They are wired in 3/series parallel so the final impedance is equal to a single driver. Easiest way to connect the drivers correctly is to lay out 3 groups of 3 drivers. Solder series connections in each group of 3 and then connect 3 groups, parallel.
Woofers are wired parallel to each other.

Tips & Tricks:
The heart of the system is Fountek’s FE87 2-1/2″ full range driver. By itself it has a fairly low sensitivity, limited x-max and limited low end response. The midrange, lower treble are however very extended and the driver even deeps in to upper bass. This extremely wide pass-band lands it perfectly for a line array where it will used in multiples and low sensitivity will not be an issue any longer. Wide response also allows it to be used with low crossed woofers on the bottom and small tweeter to extend the response cleanly all the way to 20khz and makes the crossover network easier to design.
7” Dayton Aluminum woofers were chosen to reinforce bottom end. Positioning them close to the floor will somewhat negate the need for baffle step compensation and using a pair will increase sensitivity and decrease distortions. This will also allow for the form factor of a speaker to remain a slim tower. Sealed alignment, in my opinion is preferred from the various points of view. For starters, it is the volume and appearance of the box. Secondly, ported design for this woofers will entertain the situation where the drivers will quickly overextend below port tuning frequency and may introduce distortions. Sealed response in to 80 hz on the integration hand, makes the use of the dedicated low crossed powered subwoofer easy.
Finally to the tweeters.
It’s a small dome with the neo motor. Using 5 tweeters in the array configuration may invite itself for shading the tweeters and altering vertical image of the speaker.

Box assembly.
Section, housing midrange drivers and the tweeters can be assembled separate. This is really up to the builder. One requirement to both, lower and upper compartment is extensive bracing. Because the upper section is fairly tall, it will produce standing wave. To negate the effect, it is recommended to use 5” or so of Rock-wool or Owen’s corning on the top and bottom of the midrange cabinet. The rest of the chamber can be filled with either Acustastuff (sold by Parts Express) or fiberglass if you don’t mind handling it. Woofer chamber also needs to be stuffed with Acustastuff or fiberglass.

Experiment with the R10 to your own preferences. I ended up using 10Ohm value in a fairly reverberant space. This lowered output of the midrange array by about 3.5 db.

The system is up for a reviews by enthusiasts and will be shown on the upcoming NY/NJ DIY speaker fest.

About the Designer:
Roman Erlikh is a professional furniture maker and a speaker builder.
Roman also hosts NY/NJ DIY Speaker fest in Brooklyn Navy Yard.


Project Parts List

Dayton Audio ND16FA-6 5/8″ Neodymium Dome Tweeter
Fountek FE87 2″ Full Range Driver 8 Ohm
Dayton Audio DA175-8 7″ Aluminum Cone Woofer
Acousta-Stuf Polyfill Speaker Cabinet Damping Material 5 lb. Bag
Audyn Cap Q4 3.9uF 400V MKP Metalized Polypropylene Foil Crossover Capacitor
Audyn Cap Q4 82uF 400V MKP Metalized Polypropylene Foil Crossover Capacitor
Dayton Audio DMPC-5.1 5.1uF 250V Polypropylene Capacitor
Dayton Audio DMPC-27 27uF 250V Polypropylene Capacitor
ERSE Super Q 3.0mH 16 AWG 500W Inductor Crossover Coil
ERSE 0.20mH 18 AWG Perfect Layer Inductor Crossover Coil
ERSE 0.33mH 18 AWG Perfect Layer Inductor Crossover Coil
ERSE 10mH 18 AWG I Core Inductor Crossover Coil
5.6 Ohm 10W Resistor Wire Wound 5% Tolerance
12 Ohm 10W Resistor Wire Wound 5% Tolerance
3 Ohm 10W Resistor Wire Wound 5% Tolerance


Add yours
  1. 1
    Kevin H.

    I love the look! I am sure I would like the sound. Is there a thought of building a flat pack with all the wood precut with the machine in the video. Laying out and cutting by hand and routing out the speaker cutouts would take the fun out of the build. I recently built a 15″ subwoofer from a Parts Express kit. It went together great and looks good.

    • 2

      The holes for Founteks and Dayton tweeters can be drilled with hole saws. Spacing for drill points is shown on the drawings. As far as providing CNCed baffles, I think it’s a good idea but it’s up to Parts Express. I can certainly provide Rhino5 or CAD drawing for tool path. Contact me on PETT for CAD files.
      Best regards, R-Carpenter

  2. 5
    ALex K.

    Did you try to do a smaller version of this speaker? I would like to make similar but based on 4 same mid-ranges and one woofer. I wonder if you recommend to add a tweeter (or two)?

  3. 6

    I’ve build smaller arrays as well but not with this particular driver combo.
    With 4 mids I would stick with a single tweeter. Your smaller 4-mid array will be fairly directional, vertically so I would try to match directivity by using a horn loaded tweeter. There are many good ones out there.
    Tymphany BC25SC06-04
    Dayton Audio ND25FW-4
    or if you want to go to a more robust and pricier unit Morel CAT 378 1-1/8″ Soft Dome Horn Tweeter
    You will have to redesign crossover.

    • 7
      Alex K.

      Thank you Roman, I like specs of Tymphany BC25SC06-04 tweeter. Could you please help me with link where I can find guide for redesign crossover? I’ve read (http://www.diyaudio.com/forums/multi-way/189847-introduction-designing-crossovers-without-measurement.html) but when I tried to check your crossover design for woofer part and tried to calculate woofer crossover frequency (post #10) using their formula f = R/(6.3L) I’ve got very low frequency about 250 Hz.

      • 8

        I would suggest reading Speaker Building bible on PE Tech Talk.
        Crossovers are not calculated based on the standardized values but rather are designed based on acoustic output of individual drivers as well as their summation. Woofers, mids and tweeters do not have flat response and it’s the actual output and what’s in it that are important.
        There’s frequency response, phase and impedance of the drivers and for proper design, everything has to be accounted for.
        Tech talk is a great resource for beginners and advanced builders. Start a thread, describe what you are trying to do and don’t be afraid to ask a lot of questions. You may be in for a lot of reading and learning but the results will be quite satisfying. (speaker building hobby is addictive so be careful. 🙂 )
        There’s free as well as not free software and hardware. DIY hobbyist often help each other to measure the response of the speakers (I do it from time to time in Brooklyn).

        • 9
          Alex K.

          So there is no simple guide about crossover design. Do you think I can use only 8 or 9 mids for making center channel without any crossover? As well I have another question. What was rationale for connecting tweeters like you did? It looks like only one of them will be heard because the rest four will get only 1/4 of the power that first one gets.

  4. 10

    No, unfortunately, crossover design is not a simple thing. Designing crossover for this array took around 20 hours.
    I don’t think you will have a good center channel if you just connect 9 Fountek drivers without any crossover. If you do attempt it, try to arc the front of the speaker.
    As to the last question. it’s a bit tricky. Then designing array (or any speaker for that matter), polar response of the group of drivers needs to be taken in consideration. If you ever listen to a speaker system with a tall narrow high frequency driver like Fountek NeoCd2.0M the directional character of the driver is fairly obvious. It has a very narrow vertical dispersion (roughly 15 degrees) and you can stand up or seat down, getting in and out of that beam and hear high frequency appear and disappear.
    Having 5 dome tweeters wired up so the output for each is the same, will have similar effect. Very narrow vertical response.
    Wiring upper and lower pair the way I did is a version of what’s known as “shading”. It widens vertical response of the group of the drivers and audibly blends group of the tweeters better to a line of midrange drivers.
    In comparison, if I would use just a single tweeter with a line of 9 midrange drivers, you would be able to hear directional qualities of each and the system would not sound coherent. .
    Here’s something you need to consider. Directionality of the projected frequency spectrum of the driver depends on it’s size and shape. Directionality of the frequency spectrum of the group of the same drivers depends on the number and positioning in relation to each other as well as size and shape. But we are getting in fairly advanced speaker design aspects that would only make sense if you decide to go through the 101 and 201.

  5. 11

    Great build! I can’t find anything current online about the NY/NJ DIY Speakerfest. Did it happen yet? Is it open to new people? I’d be interested to attend for inspiration!

  6. 14

    Combine response of the loudspeaker is not formed only from the on axis response data. Non linear parameters (read distortions) play a big role as well as off axis performance. Arranging mid-woofers in a line, for example will cause a drop in the upper octave response because of how drivers interact with each other.
    Basically, combine response of a line of the woofers will be much different than a response of a single woofer and this is all needs to be considered while the speaker is developed.
    Full range line arrays have been build successfully and there’s no reason you shouldn’t try. I would suggest using some sort of the DSP for correction (because of it’s flexibility) and possible measurement hardware/software set up.
    It just would be entirely different original design from the E-Array.
    Best regards, Roman.

  7. 15
    John Paulicelli

    Hi. I am intensely interested in building these speakers. I have been building speakers for many years and I have never been more drawn to a project than this one. You mentioned that it was up for review at NY/NJ DIY Speaker fest in Brooklyn Navy Yard. I would like to know if these were actually reviewed and what the outcome was. I am after a big, realistic sound and I think this project fills the bill. Hope to hear from you, John P.

  8. 17
    John A Paulicelli, Jr

    Thank you, Roman. You have been very helpful I have decided to build these, but I sure would like to know what your friend had to say about them. Also, on the crossover three separate schematics are shown. How do they all interconnect??? Again thanks, John.

    • 18

      As far as 3 schematics of the crossover.
      There’s only one crossover. It’s electric filter, altering frequency response, impedance and the phase.
      3 other diagrams show wiring for the groups of drivers. You have to look at this speaker, technically as a 3 way design.
      Only instead of the single tweeter as it would be in the conventional design, you have a group of tweeters. After you wire up tweeters as shown, you end up with a single set of – and + wires that are connected to the crossover section T.
      Same with midwoofers. Wire 9 drivers as shown and you have only 1 set of – and + wires, connecting to the M section of the crossover. I broke the schematics down in to 4 pictures so the over all diagram is not overcrowded. HTH
      BTW, I like this speaker so much myself that a high end version based on Seas Excel drivers will be designed in a near future.

  9. 19

    This is the review.

    I just wanted to let you know how much I enjoyed my time listening to your line arrays. It really changed my understanding as to what is possible in my small listening room. When I initially heard them at the NY DIY I was extremely impressed by their sound in your large shop. I couldn’t believe how inexpensive the drivers were. After all, midrange drivers that were 7 bucks each-what could be expected. The overall sound had a lot of the same characteristics as your larger array which I heard multiple times in your shop as you know. I wanted to give your new smaller array a try in my small listening room but was a bit apprehensive thinking that in my small listening room I always needed small speakers. Over the years I tried a few three way floor standing speakers but they never worked out. I always seemed to come back to two way monitors on stands.

    After you graciously allowed me to bring them home for a try I placed them in my living room and my first thought was these don’t really visually over power the room. I guess because they are quite narrow, they don’t obstruct the view of the room and don’t take up more floor space then a pair of monitors on stands. I hooked them up to my 100 watt tube monoblock amplifiers and sat back for a listen. From the first note I knew you had built something special! They filled my room with a terrific tonal balance that I never heard before in my room nor did I think it was possible to have this much room filling sound. My room is no longer to small to enjoy full range music at realistic volumes! I pulled out CD’s I hadn’t listened to in years because my speakers were not doing the music justice! Roman, your line arrays are the finest loud speakers I have had in this room period! Speakers I have had (some close to $10,000) were very good but none of them filled my room with music in a way your line arrays do. I truly felt I was sitting in the best seats in a hall. I was concerned that a line array would not image well in my room and it would be like listening to a large wall of sound with no imaging and unrealistic placement of instruments and voices. Nothing worse then listening to vocals from a singer with a 10 foot diameter head! This was not the case. I don’t understand how its done but the arrays imaged better then any speaker I have heard in my room. Image height and depth was just spectacular. The bass response was excellent and did not overpower the room. There was no bloated one note bass here. I heard bass on some of my CD’s I never heard/felt before and didn’t know was on the CD. I truly didn’t hear anything negative that I would ask you to change in the tonal balance of the speakers. I heard a bit more transparency in the mids and highs that had a little more sparkle from other speaks but none of them produced the room filling sound which to me made for a much more enjoyable listening experience.

    Thanks very much for the opportunity to listen and learn from these glorious speakers. They really changed my belief as to what is possible in my small room and at this price range.

  10. 20
    dennis nagle

    Hi Roman. I had the same thought this morning so I looked up Fountek FE87 and found this project. Before I talk about the project. I was in the Brooklyn Naval Ship Yards in 1977 on the U.S.S. Savannah and stood watch with a welder named Roman. Could that have possibly been you??? The Roman I worked with raced 250CC flattrackers on the weekend.

    Anyway, the FE87 is on super sale now and I was going to use 20 per side in 6 foot+ tall cabs. The data sheet shows it goes well into the high 20khz. If so, why did you use tweeters? Or, is the data sheet um……optimistic? Cheers, Dennis.

    • 21

      Hi Dennis.
      While I have welded on the side of the ship it was not 1977. I was a bit too young back then. 🙂
      The datasheet, manufacturers provide, only serves as a guideline. The response is affected by placement on the front baffle and interaction with other drivers. You also need to look at what’s in the spectrum of the response of the driver. As you probably heard, drivers produce harmonics or distortions. In extreme cases distortions are reflected as high magnitude frequency response peaks (Dayton RS Aluminum or Seas Excel Magnesium). But in many cases additional measurements need to be performed by the designer. The distortion magnitude in relation to the fundamental output of the driver creates pleasant or unpleasant sonic signature of the system. Fe87 is not terrible in the upper octave but a dedicated tweeter will have an ability to take over and create more balanced and life like representation of the source material.

      If you want to build a full range line array, it’s not impossible at all. Murphy Corner Line Array is probably the project I would suggest as inspiration. DSP now days has gotten very affordable too and adds a lot of flexibility to crossover design.
      HTH, Roman.

  11. 22

    Hi, for a mixed system audio and PA, I’m considering building something smaller. The idea would be to build small enclosures that could eventually be stacked on top of each other. Each enclosure woud consist of one 5″ bass-midrange unit and 3 Dayton Audio ND16FA-6 5/8″ Tweeters, 2 extremes wired in series to each other. This doublet is wired parallel to the center tweeter #3. The tweeters would be mounted on a slightly bended support , cut off frequency would be around 5K Hz at 6dB / Octave. similar to each cube of http://www.ld-systems.com/fr/series/serie-curv-500/curv-500-ps-systeme-line-array-portable-power-set-avec-barres-d-espacement-et-cables-hp/
    What do you think and eventually suggest ?

    • 23

      As a single unit build, it sounds good. But if you build stack-able speakers in the future, then each 3-tweeter unit is shaded. I am not sure if this is ideal for PA application.

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