Project NEXUS... A timbre matched family of Hi-Fi/HT speakers

Discussion in 'DIY Speakers and Subwoofers' started by Matt Grant, Feb 10, 2014.

  1. Hi, hoping for some help. I am building the MTMWW tower speakers, and am up to making the crossover. On the PCB boards designed by Matt there are codes printed for each component. What do these mean? I am thinking they have something to do with what component joins to what?? I can easily place each component the same as the photos above, but am looking for an easy diagram showing what component joins where for this configuration. Any help appreciated.
     
  2. Did you miss the crossover schematic for those on post #6? That shows how the crossover components are wired up.

    Otherwise if you bought the PCBs from me I include a layout diagram for the parts.
     
  3. No I did see the schematic and should be able to work it out. I have just seen some schematics that show the components drawn in position with each connection drawn in. Just looks a lot easier to follow. First time doing this and don't want to make any mistakes.
     
  4. #104 Matt Grant, Dec 4, 2018
    Last edited: Jan 13, 2019
    This might help then:
    Nexus MTMWW Tower PCB component layout + Traces.png
     
  5. Awesome, that is perfect Matt, thank you very much. Just one more question in regards to the crossover coils. I noticed the 0.1mH and the 1mH have a centre wire and an outside wire on your diagram. With the 2- 0.4mH coils which way do the run? ie which is the centre and outside wire in you schematic?
     
  6. It does not matter which way the leads are run, there is no polarity to the inductors.

    When I am installing coils like that I usually position them so that the lead length to the through holes is shortest whichever direction that might be for a certain brand or value of coil.
     
  7. Hey Matt

    I have fallen in love with your Nexus project and im seriously looking into building them. It will be my very first try at DIY speaker building so i'm somewhat of a newbie. I choose your project so i didn't have to design everything from scratch so I would be reasonably sure to be successful and because I like you have used Dayton Audios the way you have.

    Being from Denmark I have redesigned your speakers into metric dimensions and taken the liberty to make the towers into a square design - but I've run into a issue sourcing the 1-5/8" ID x 4-7/8" L Flared port you are using for the small TM's - I can only get that from PE in the US, which is a bit of a pain. I cant read directly what frequency you have tuned you port to, but i'm shooting for 60Hz. My/your box size is 7,07L internal volume (internal dimensions W150mm D206mm H268mm) and i will build them out of 3/4"/19mm MDF. I'm able to get a 1-7/8" ID x 5-5/8" L Flared port, a 1" ID x 4" L Flared port or a 1-1/2" ID x 4" L Flared port. What is my best potion in your opinion - I've looked into calculating the port on my own but i'm worried about chuffing since I honestly have no clue what i'm doing. Hope you can help me with this final step. Thanks in advance.

    Hers a picture of your Nexus speakers (the Danish version). I think they will end out being in white high gloss finish.
    Screen Shot 12-09-18 at 07.25 PM.JPG
     
  8. The enclosure for the TM design is tuned to about 60hz.

    These ports should work for the TM design if they are easier to get:
    https://bekent.dk/br-45tr.html

    I think the speakers will look great in a gloss white finish!
     
  9. #109 LexxDk, Dec 10, 2018
    Last edited: Dec 10, 2018
    Hey Matt.
    Thanks for the quick reply. Yes this port is way easier to get. I have to buy stuff there anyway. This really helps me out.
    Should I keep the full length of the port?
    By the way, do you have any pictures of the dampening inside the different speakers? If not, I'm planning to follow the advice from Troels Gravesen homepage about cabinet damping.

    Thanks for the help
     
  10. Yes keep the port at full length.

    I don't have many good images showing how I put the damping in these cabinets but the guide by Troels is a good approach and would work well for these cabinets.

    Here is the MTM (older narrower cabinet design) where I have the inside lined with recycled denim insulation.
    [​IMG]

    And one of the Tower cabinet design as well when I was stripping it down to re-apply the veneer.
    [​IMG]
    [​IMG]
     
    LexxDk likes this.
  11. You can get the same port tube from a EU store: http://www.audiohobby.eu/

    You want this item:

    https://www.audiohobby.eu/en/jantze...tml?search_query=Jantzen+Port+Tube&results=12

    It would be great if you share your metric plans. In my country we also use metric system.
     
  12. Hey mga2009

    Sure ;) I can share them. I'm currently working on finishing the drawings as I want them. I'm planing to route out tracks for my internal braces and I'm currently working on that. What are you looking for - I mean how detailed planes are you looking for?

    My thinking in my design revolves around copying Matt's internal volume. I really wanted to make my speakers to have a similar design. I was shooting for a design with rounded sides, but it was not possible to make with my current set of tools. My second design idea was a "squared" evolution of the rounded design - but it became too big a pain to cut out :p so I abandoned that idea as well. Anyway - the first picture is a sketch of the internal volume of the two first design ideas.
    Screen Shot 12-14-18 at 07.25 PM.JPG

    I came up with the design by first calculating the internal volume of Matt's original design, then drawing a model of the internal volume in CAD (I used autodesk inventor) fiddling with the dimensions until the volume and the looks where to my liking - remember to take the internal bracing into account if you are going this route.
    The lower left pics shows Matts design volumes in Liters (without the braces) and my final "boring but makeable" designo_O. I also made a model of the volume finale design - The top/upper chamber is not used for anything but is a consequence of having make a complete box. Hope this makes sense. in the bottom there is a small chamber which can be avoided - I chose this to get a nice dimension on the front baffle (its 1200mm). Some of the measurements have to be tweaked a little when converted from inch to mm.
    Internal Volumen.jpg

    An easy way of finding the volume of the bracing is to draw them all as one piece and letting your CAD program tell you the total volume of your bracing - very easy and fast and most important!! No energy spend on doing math :D No calculators where hurt during this design:p:p:p
    Screen Shot 12-14-18 at 08.18 PM.JPG

    I used the same method for the CENTER and the TM's. My center design is longer than Matt's original but has the same volume - but I might change the center design - i'm not sure

    I'm planing to share my build here, when I start cutting the MDF:D

    Cheers
     
  13. Hey Matt,

    I am making the MTMWW towers my first speaker build. They should make a good match for my recently recapped Marantz 2325 receiver (thanks to our friends at AK for their guidance). Time to move on from the Cerwin Vega rock and roll speakers to more jazz friendly units.
    I have just completed the cabinet construction using 3/4” MDF and these are certainly substantial pieces of furniture! I plan to cover them in cherry since your originals looked really good in red with the all black speaker faces and black grill covers. I will post pics when that is complete.

    Do you have any crossover boards for the towers available?

    Thanks for the excellent plans,

    Keith
    Denver
     
  14. #114 Steeve-O, Jan 13, 2019
    Last edited: Jan 13, 2019
    BTW, on this scheme and also on the instructions that come with the PCB the LF R1 is missing I believe. I noticed it for the Tower and center channel. I think it’s a 0,51 ohm resistor that is supposed to go there?

    I also have a question. I lined the inside of my cabinet with walmart eggcrate foam (open cell). I left clearance for the port. Should I add polyfill in the upper part of the tower? Would it help with standing wave?

    For the mf/hf compartments in the center and tower wich is better? Polyfil, eggcrate foam or both? I can’t seems to find denim here.
     
  15. Thanks for catching that, I did forget to add the text for 0.51 Ohm resistor in the LF R1 position on those diagrams.

    Adding polyfil to the top portion of the cabinet won't hurt, I do have the top angled section on mine lightly filled with material.

    For the MF/HF section it shouldn't matter, you just want all the empty space taken up by damping material leaving only small holes for the drivers to set into. If using foam try not to compress it as that reduces it's effectiveness but polyfil should be lightly packed in there.
     
  16. Matt, How are you doing it's been a while. I few years back I built a new house with your run of the mill media room and I just wanted to report in and state that your speakers are still a rockin the neighborhood. I have driven these hard and loud from epics like the Avengers in DDS to Heavy Metal bands like Pantera, Metallica and Tool with few nights of Mozart or Pavarotti in between and I am still amazed at how good they sound especially for the price and I still can't believe I don't see more of them on the internet. I think the angle on the back scares a lot of people with wood working skills so I plan on rectifying that by building another set that's just plain ole square and will post my progress.

    While I spend a lot of time in the movie room we also have a living room that's never had much of anything but a Samsung soundbar/woofer setup but now that I have settled in here and find that the kids spend most of the time in my room playing xbox and wii on the bigscreen I never have time to listen to my music on anything so for the last few months I have been looking for a new set of living room speakers.

    I really wanted to build the Statements one day but I just don't have the room for them given they need to be so far off the wall and my left right space on this project is also impacted because we wanted a fireplace we never use and then I was thinking about doing the Anthology's MTMWW Tower which are very similar but after months of sifting through forums for a new set of decent rockers I have decided why not go with what works and build another set of these.

    My Main issue is that I have no room for a sub and if I did put one in the only place I can find, it would have to be wireless or something because there is no way to get a LFE signal or speaker wire to it without running the wire 100 feet around the house so my primary goal was a set of speakers that have the best amount of bass in a space that is 12 inches wide and no more than 20 inches deep because that is all the room I have on either side of the 70 inch plasma in the L/R area.

    So my questions are, Number one

    do you still have any of those cool crossover boards you made because that would make this a lot easier.

    In making a square cabinet, does the addition volume behind the MTM affect much or should I block some it off. I cant see that it would I just wanted to confirm.

    I don't think I will but is there any reason I can put the port tube facing front or even down firing instead of the back or will this impact the bass. These are going to have to sit about 3-4 inches away from the wall to fit. I might be able to squeeze 5-6 by pulling the media center a little more off the wall to fake the wife out but she she gave me a no fly zone any further than front of the media center. She would be one of those people that says: whats wrong with the sound bar, why cant we just keep using it....

    Also since I was so busy at the time I never had a chance to post photos of my detailed build so I found them all and will be posting them here as well should others may want to follow.

    Thanks again for designing such a wonder speaker. In 1994 I was blessed with the find of the century at a local pawn shop where a man had just hocked his Carver AL-III plus speakers in mint condition and never showed to pick them up so I got them for 750.00 each and for almost 20 years I had those in my old house powered by a Onkyo Integra TX-SV919 as a head unit and Kenwood M1 power amplifier that was rated down to 2 ohms. The Carvers were rated at like 2.8 or something like that and the Kenwood was the only thing at the time I could find that would not blow up after a while running them at full blast. So the Kenwood just drove the Carvers and the Onkyo everything else.

    Sadly 20 years later, the woofers finally started to disintegrate as well as the black foam that ran up and down the 7 foot length of the face and I most likely could have repaired them but the woman was tired of looking at these 7 foot monoliths in the living room so I gave them to a good friend of mine when I moved. They also weighed about 70lbs each so I wasn't looking foreword to moving them either.

    Point is, I had a good reference point for many years and I can say with out a doubt that with the Nexus MTMWW now in place, I really don't miss them. Those Carvers were almost 4000.00 new and for someone to create a tower that sounds equally good for a few hundred in parts is quite an accomplishment. Great job and I hope more people find these soon.
     
  17. I'm glad you like them so much.

    I do still have crossover PCBs for these available.

    Making the cabinet back square instead of angled is no problem, You don't need to change anything else to do so. Internal volume of the cabinet will be increased slightly but that won't hurt anything.

    The port can certainly be placed on the front of the cabinet, I only placed it on the back for appearance purposes. I will note that it only needs 2-3" of clearance to work effectively so you could possibly leave it on the back if you wanted to.

    It should be ok to place these up a few inches from the wall, you will get an increase in low bass response and output. Depending on the room gain it could end up being excessive/boomy but if you are using a receiver with room correction it should be able to tame that.
     
  18. I built these a few years ago and got too busy with other things in life to post the build photos but now I plan on building another set for my living room with a few modifications to the cabinet and thought I might share my process on the previous as well as the new ones once I get the parts in.

    I will probably have to post this in several parts due to the quantity of photos so bare with me as I try and get this right.

    My past is many trades or mostly hobbies one of which is woodworking. As stated in a post above my previous mains were a set of Carver AK-III Plus speakers I had for almost 20 years until they gave out and started searching for another set of replacements and when I saw these in a random google search I fell in love with them.

    The first photo is my make shift movie room and my Iphone would not take a better picture so sorry for the quality. That is a 130 inch screen for reference, I am driving these new speakers with a old school Yamaha M65 amp which weighs about 50lbs and I am using a Yamaha RX-V1800 AV Receiver to control everything. The setup isn't perfect but it works. Those speakers sitting on top of the Nexus Towers are some RCA/Optimus Dipole Linaeum tweeters I had in storage that I am using to produce my Dolby ATMOS and have some JBL Loft 50 for the rear surrounds. I'll be building some new subs this summer but currently I have a one of the older 12 inch JBL Venue subs that has been retro fitted with a 600W amp as well as a BFM Tuba sub that sits behind the main couch also powered by a 600w amp for LFE. The Nexus Towers put out plenty of bass and most when listening to music I turn off the subs because it's just too much. I really like the TubaHT but my next build will be more of a midbass unit like the FLEX-12 VBSS or the PA460 which I think might be too much. The media room is on the 2nd floor and the room already shakes when the bombs go off, I just feel like I am missing that chest punch I read about on the AVS Fourm from the GTG meet a few years ago.

    Anyways enough babbling and on with the photos. All I can say if you decide to build a set of these you will not be disappointed. They sound every bit as good as the Carvers I had and I have run them hard for 3 years now and they still sound as good as they did new.


    [​IMG]

    I built these out of Oak plywood because I had a few sheets and hate working with MDF but I also re-covered the entire cabinets in oak veneer because the quality of the oak wasn't that great and I wanted to cover all my nail holes. I clamped and glued all of these but I also shot 1 3/4 16g brad nails into most of seams to keep the alignment from moving when clamping.

    [​IMG]

    [​IMG]

    [​IMG]

    Before I cut the speaker hole I laminated the two front with veneer so that holes would match instead of trying to go back and trim later. The rest of the cabinet I left bare until they were complete then I laminated the rest.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    The hardest part of building these cabinets was getting that angle on the back but that what makes them unique however getting them to all cut and match up was a PITA thats why the next set will be square,

    [​IMG]

    [​IMG]

    All in all they came out pretty good. What I did was tack all 4 sides together on top of each other as one big sheet and then I made one cut on the table saw with a sled jig I made. That way the angle was the same on all four without me having to re-produce the same cut 4 times.

    [​IMG]
     
  19. [​IMG]

    I covered the inside walls of the speaker with some batting I got at the cloth store used for making comforters or quilts I guess. It was about a 1 1/2 think and I just cut to fit and used a power stapler to cover the inside.

    [​IMG]

    When I veneered the back I used one long sheet starting at the end and then scoring the seam where the back angles with a box knife to make the veneer break a little when I folded it down to the rest.

    [​IMG]

    Veneer takes time and patience. I always cut the sheet where its about 1/4 inch larger on all sides that the piece I am applying it too. Once I glue it down, I use a iron to smooth it all out starting at one end and working side to side all the way to the other end until it's all firmly seated and then immediately I cover that area with a piece of 3/4 plywood that is at least the size or or larger than the piece I just applied and then clamp the scrap plywood down all the way around with 6-7 clamps for a few hours til it sets to keep bubbles out.

    After it sets, I use a palm router with a formica ball-bearing trim bit to go around the edges and flush everything up and then use a piece of 120-180 grit sand paper wrapped around a 1x2 by 12 inch long to gently rasp the edges.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    For the base on these I drilled 4 9/16 inch holes in the bottom of the tower in each corner of the bottom 3/4 of an inch from the inside walls. With the speaker on it side I ran each of the 4 inch 9/16 inch bolts out the bottom from the inside reaching thru the speaker hole. I then slid on the first base which was cut from 1/2 MDF about 3/16 inch larger than the base of the speaker on all sides and then put a washer and nut on each to firmly hold the first base in place.

    I then cut 4 1-1/2 inch length pieces of some ~1-3/4 inch steel electrical conduit I had (which I spray painted a dark silver) and slid down on each of the 4 bolts sticking out from the base and then slid the next base down on those. The base was cut 1 inch larger than the base of the cabinet and rounded off with a trim router. After I made sure all the conduit tubes were centered I put another washer and nut on the bottom of the last base to sandwich them all together and tightened firmly. This left me with about 1 inch of thread still sticking out the bottom which basically became my floor spikes for the speaker to sit in the carpet firmly. I dont know if all that made sense or not, I failed to take a photo of that step but I can draw it up if anyone is interested.

    On making crossovers, here is my tip. Of ebay I ordered some various sizes of the cheapest electrical breadboards I could find. I got some of these for like 3-4 a pack for 5x7 and 4x3 and 6x8 or something like that, They work great for hold parts for making crossovers

    [​IMG]

    [​IMG]

    Project complete. On the stool is my test amp. You can get these TDA3116 class D amplifier boards off ebay for less than 20 bucks and they seriously pack a punch. That one on the stool is 100 watts per channel and I feed it with my ipad or testing. They will pretty much run off anything from 12 to 28 volts. I run mine with a 22v 5a laptop power supply.

    [​IMG]

    EOL.
     
    louisdamani, Erich H and marc seals like this.
  20. Well there, after 3 years I finally got around to my pics. How do I order some of those boards? I would like to get 2 sets or 4 speakers total. After I build this next set, I have a friend that wants a set too. I can paypal if you have that.
     
  21. Here are my Nexus TM still WIP.

    [​IMG]

    I made them a little bit taller and deeper, as I added an internal brace. Front baffle is 2.4cm thick... made some mistakes and needed to install a new front...

    I habe de XO assembled and within the next days I will veneer them and install the drivers.
     
    louisdamani, Erich H and marc seals like this.

Share This Page