Blog Forums DIY Speakers and Subwoofers Who wants to Design a Speaker with Me?

last updated by tvor-ceasar 2 years ago
9 voices
86 replies
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    • #11127
      123toid
      Keymaster

      Anyone interested in helping out design a desktop speaker?  I am doing a new video on how to design a speaker from start to finish.  This will be the thread for it.  Feel free to ask any questions.  I’ll also add the files, so you guys can try out different crossovers.  Ask questions about what is being done and why.  Who is in on this fun?

      The drivers to be used are the PC83-4 and the ND16FA-4.  

      I am thinking small sealed to be used with the mini earthquake. Thoughts from anyone?


    • #11129
      tvor-ceasar
      Moderator

      Nice looking graphs, though the SPL levels are a bit disparate. Can always tune down the tweeter in the crossover.

      Would you be able to redo and repost the  measurement graphs on the Mini Earthquake? I’ve looked at them with 3 different browsers and none will pop out like a normal picture does and I just cannot see/read them in the post. I’d like to see where that lands before going forward. That’ll give a sense of what to do with the upper set of drivers.


    • #11132
      123toid
      Keymaster

      I should have the ZMA and FRD files later today.  We can see how much attenuation we’ll need to put on the tweeter. My hope is to make this as simple of a crossover as possible for people. I’m not sure why they’re not opening up fully for you. I’ll have to add the mini earthquake stuff for you when I get back to the computer. 

       


    • #11133
      tvor-ceasar
      Moderator

      @123toid

      I don’t know why either, I’m using my phone and 2 different desktops with both IE and Chrome. Other ones do, for example, the photo of the receiver you just put up does. 

      Totally bizarre.

      Totally.

      🙂


    • #11134
      123toid
      Keymaster

      That is really weird. I’m getting ready to glue together the enclosures now. I’ll try to re-upload those once the kids wake up from their nap. 


    • #11135
      tvor-ceasar
      Moderator

      @123toid when you go to wake them up, use the link I just added above.


    • #11137
      tvor-ceasar
      Moderator

      Using the T/S numbers provided for the PC83-4, I plugged them in and found:

      Sealed – in box Q of 0.7 (considered optimum) gives an interior volume of 0.09 CuFt, and a FB of ~104 Hz

      938-PC83-4-sealed.mp3

      Ported – using the same box size above (0.09 CuFt), you can go a little lower with a FB of ~74 Hz and a F3 of ~71 Hz

      939-PC83-4-Ported.mp3

      Using the inside volume of 0.09 CuFt, and since the thinnest regular useable thickness of MDF available at the Home stores is 1/2″, a couple of box sizes:

      Golden Ratio – 9-3/4″H x 6-1/3″W x 4-1/3″D

      Acoustic Ratio – 7-3/4″H x 6-1/3″W x 5/14″D

      I thought that since the PC83-4 is only a hair more than 3-1/4″ wide at the frame, the width could be made a bit more skinny, maybe 5-1/4″W, which would change the Golden Ratio to a depth of 5-1/4″ also. Then glue another piece to the front, making the mount area for the PC83 1″ thick while keeping the tweeter area 1/2″, and you could then do a 1″ round off on the edges there, while transitioning to a smaller one on the upper area. That’d help time align the drivers, while helping to mitigate baffle-step.

      Crossover TBD.

      Sound like a starting point?

       


    • #11138
      123toid
      Keymaster

      @tvor-ceasar

      I think I want to go smaller size over a standard Q.  We can add some poly, but even making it considerably smaller really doesn’t affect the response that much. I should have mentioned, I already had the box cut (sorry).  But your work is perfectly on point.  I kept it at 7″ by 5″ by 5″  Which is not the golden ratio, but I have used it for this driver and with the 6db high pass at 100hz that is built into the Lepai, it seems it should work out well.  Maybe I’ll make a second box which has the tweeter behind the woofer for better acoustic alignment.  That is a cool idea. 


    • #11139
      123toid
      Keymaster

      Here is the response of the W5.  This will be a 2.1 unit.  THe two desktop speakers and this as the sub. 


    • #11140
      scotty
      Member

      @tvor-ceasar

      What is the difference between the golden ratio and the acoustic ratio?
      Do they have different internal volumes?

      Scotty

       

    • #11141
      derek
      Participant

      These would be pretty similar to the Reveals. I still have the parts for them, just never cut the boxes. 😱 I don’t have a shop so kits are a big help to me. That was Olympic level procrastination though. 

      The Reveals were not the only ones though. I was taking inventory of the drivers in my collection and making sure that the correct crossover parts had been obtained. Sadly at the time of purchase I didn’t know that inductor DCR was even a thing or that it mattered. Luckily just a few cheaper ones were wrong.

      Also, sorry for derailing the thread. Carry on.

    • #11142
      tvor-ceasar
      Moderator

      7x5x5, is that internal or external measurements? If external, what is the board thickness? Looking for internal volume.

      Thanks, I can see the graph now. Still no clue as to why it did that on my end.

       

      Hmm, add a separate enclosure on top, backset, that would allow round over of the 3 edges not on the desk and would make for a visually interesting aesthetic. Kinda diggin’ it.

       

      Did you play that link for the kids? What interestingly fun times they were!

       

      Addendum:

      Looking at the tweeter dimensions, a 3″ x 3″ box, 4.5″ (0.5″ shorter than the main box depth) or what it needs to be set back to align. Nice rounded edges, maybe all 1/2″, would give it an almost Art Deco style.


    • #11146
      tvor-ceasar
      Moderator

      Aw shoot, you guys replied while I was writing. Sorry I missed you.

      @Scotty,

      Golden Ratio is something you’ll find throughout time immemorial, from nature to art to man made objects. If you look back at most older speakers (mid to late 70’s and earlier), they all have the same basic shape. The ratio is 1.6 units high x 1 unit wide x 0.6 units deep. The numbers actually go on forever, but 1 place is sufficient. It is reputed to be a very aesthetically pleasing ratio.

      Acoustic Ratio is designed to minimize interior standing waves, and like above, the numbers are basically 1.2 units high x 1 unit wide x 0.8 units deep. Also like above, these numbers go on and on, but 1 place is close enough. 

      Both ratios contain the same interior volume.

      Thing is, these are just starting points. From the initial box to final product may be many iterations and many moves away from initial calculations. This is both the fun and frustration of the hobby. 

      @Derek,

      Sounds like a shot at getting going on the Reveals. I saw a guy who used hand tools in his kitchen to build some really nice cabinets (speaker boxes). And his kitchen was tiny. Lucky if it was 10′ x 10′ with counters and table.

       

      PS: here’s a link that gives some insight into the Golden Ratio.


    • #11147
      123toid
      Keymaster

      @derek

      It actually is the same enclosure as the reveals. Since I knew that the enclosure worked really well already with the PC83, I wanted to use it again. I’m thinking that this tweeter will actually be a better fit for the PC 83. That is why I decided to try it on this end. But I don’t know yet. I’m going to try to get some measurements tonight. But yes, that is some serious procrastination, lol. 🤣 

      @tvor-ceasar

      Those are external measurements with half inch material. The woofer is going to be round over and set behind. So the acoustic centers will be fairly off. But I’ll just equate for that in the crossover. I’m going to try to get some measurements for everyone to play with tonight. Then I’ll go ahead and hook all of them up and do some sound tests and measurements. And then we can decide together what we think looks like the best combination. Then I’ll do a video and give you guys all credit. 

      PS, the kids enjoyed the song.


    • #11148
      tvor-ceasar
      Moderator
      Posted by: @123toid

      @derek

      It actually is the same enclosure as the reveals. Since I knew that the enclosure worked really well already with the PC83, I wanted to use it again. I’m thinking that this tweeter will actually be a better fit for the PC 83. That is why I decided to try it on this end. But I don’t know yet. I’m going to try to get some measurements tonight. But yes, that is some serious procrastination, lol. 🤣 

      @tvor-ceasar

      Those are external measurements with half inch material. The woofer is going to be round over and set behind. So the acoustic centers will be fairly off. But I’ll just equate for that in the crossover. I’m going to try to get some measurements for everyone to play with tonight. Then I’ll go ahead and hook all of them up and do some sound tests and measurements. And then we can decide together what we think looks like the best combination. Then I’ll do a video and give you guys all credit. 

      PS, the kids enjoyed the song.

      Check my addendum above. I was typing while you were. You could even slim it down to 2.5″ wide if need be. You could trim where the tweeter box hits the main box with some small cove, if you can find it or maybe some 45° trim. 

      I ran the numbers for outside dims and 1/2″ board, comes out to be an in box Q of 0.79 and a FB of ~117 Hz. Still a nice bottom for such a small driver.

      Glad the kids liked the song. It’s never to early to introduce the kids to Zappa. 😀

      941-PC83-4-reveals.mp3

       


    • #11150
      123toid
      Keymaster

      Here are the FRD and ZMA files.  I came up with a z offset of 1.07in in Xsim.  Let me know your design and I’ll test it.  I will say, that these ND series tweeters can sometimes act different then they measure and this is the case with this.  Give it your best shot.  

      942-collab.rar

       P.S.  If you need any help on how to import files or put in the z-offset in xsim.  Just ask.  I’ll post pictures to help along the way. 


    • #11151
      diy-audio-guy
      Participant

      I used the pc83 in my boombox build.  Nifty little driver.

    • #11152
      123toid
      Keymaster

      @diy-audio-guy

      I agree. It’s a great little cheap driver. Did you port yours? Or keep it sealed? I’m curious what people are going to come up with with the crossover. If this goes well, we’ll do another community build with some buyout speakers. That way people can get some experience and if they want to build some, they can do that as well. I’m thinking an MTM for cheap. 


    • #11153
      diy-audio-guy
      Participant

      @123toid

       

      Sealed, and I paired it with an air motion transformer tweeter.  Mostly because I ended up with an extra pair of earmotion transformer tweeters.

    • #11154
      123toid
      Keymaster

      @tvor-ceasar

      Let’s redesign the box. Maybe we’ll try a ported. So if you want to design a box, let me know. I had already figured out a crossover that’s viable. But I was going to wait to see what everyone else comes up with.  INstead, I’ll make a new box and take new measurements. Do you use a program like SketchUp?  I’m more of a visual person to understand the box. 


    • #11155
      tvor-ceasar
      Moderator
      Posted by: @123toid

      @tvor-ceasar

      Let’s redesign the box. Maybe we’ll try a ported. So if you want to design a box, let me know. I had already figured out a crossover that’s viable. But I was going to wait to see what everyone else comes up with.  INstead, I’ll make a new box and take new measurements. Do you use a program like SketchUp?  I’m more of a visual person to understand the box. 

      I was looking at various programs last night. I have AutoCad at work, TurboCad at home, plus Blender, Inkscape and Gimp in addition to the venerable Paint.

      I also looked at ones that were online, and since SketchUp is a widely used program, I think I’ll sign up for that. I just have to figure out how to do 3D, all that shading and faces stuff. I use Cad for Civil drawings, so 2D lines and topographic surfaces are a no brainier, but doing small stand alone objects is a new thing. I’ll hit up the SketchUp website tonight. FYI, I’m a numbers guy so I can then translate to drawings. 🙂

      I also downloaded WinISD and XSim, so there’s another step done.One of the original boxes I came up with was a 0.09 CuFt box that tuned to FB 74, F3 71, and 0.6″D hole in the face (1/2″). I think a 1″ port was somewhere around 3″. I can remodel it to the Reveal box size. I wonder what it would look like if we used the basic Reveal box with a smaller box on top, all open to each other. Hmm…


    • #11156
      123toid
      Keymaster

      @tvor-ceasar

      It doesn’t matter which program you use. I just need to visually see it. And have an idea of the dimensions. I like the idea of doing a cool looking box. Don’t worry about the size, we’ll completely redesign the size. Then I’ll get you guys the new measurements. I’ll also do a video on how to import the measurements, just so everyone knows what to do.  I like the idea of having the woofer stand out further from the tweeter, so I think that’s a good idea. I’ll redo the box in the next couple days and then I’ll take some measurements


    • #11157
      speaker-toni
      Member

      @123toid

      I’m not really familiar with all of these crossover simulation programs so I probably won’t be a big help here. Although I would like to try them its mostly because I couldn’t find any that work on Mac yet, so maybe someone has suggestion for me? 

      But I was wondering what exactly you meant with the woofer standing out. Do you want to fully time align it with an extra step on the baffle? 

    • #11158
      tvor-ceasar
      Moderator

      @speaker-toni

      Can you use Excel On your MAC? There’s a guy who made up one heck of a spreadsheet that does just about all of the stuff we are talking about. I’ll see if I can find it for you.

      Found it.
      http://audio.claub.net/software/jbabgy/jbagby.html


    • #11159
      tvor-ceasar
      Moderator

      First attempt at SketchUp. This is the sealed version based on the Reveals, 5″ x 5″ x 7″, with a 2″ x 3″ x4″ tweeter box on top. Has the Z-offset. I wanted to round-over the edges, and put a 45 Deg. bevel around the tweeter box base, but it was not that easy to find how. If anyone knows, would you mind enlightening me?

       I have the SKP file if needed.


    • #11161
      elliottdesigns
      Participant

      @tvor-ceasar

      Pass over the dimensions and I can do a full sketch up in Solidworks, I can even run fluid dynamics if we are designing it with a port. I’m happy to do any modeling or simulation for you guys. 🙂

      I say this because I don’t believe SketchUp has those kinds of modeling tools, and I’d just be happy to help in any way I can.

      Also as for crossover software, I really like Vituix CAD 2.0 as it integrates lots of features, with WinPCD for looking at how the crossover and baffle arrangement effects polar response.

    • #11163
      elliottdesigns
      Participant

      A few examples of my most recent 3D printable 2 part bookshelf speaker:






      I also have a large variety of wood and paint types that I can render from:

      An unfinished ash for example


      Just to give an idea of what I can do for any of your projects guys. I want to give back from what I got from your videos and general support in this forum.

    • #11164
      speaker-toni
      Member

      @tvor-ceasar

      I’m not currently using it but I could get Excel. I’ll look into it, thanks! 

    • #11167
      elliottdesigns
      Participant

      @speaker-toni

      The two I mentioned are free and don’t need excel. WinISD doesn’t need excel either and is also free (good for enclosure design).

    • #11171
      tvor-ceasar
      Moderator
      Posted by: @diyaudiphileelliottbridge

      @speaker-toni

      The two I mentioned are free and don’t need excel. WinISD doesn’t need excel either and is also free (good for enclosure design).

      @speaker-toni

      Your MAC should be able to run Windows Compatibility modes, so you should be able to use these, I think. I’m not a MAC user, and what I do know of them is mostly through reading. So take that with a grain of salt, so to speak. In this case, Google is a better advisor than me. 🙂

      I was just looking for something that would run natively, more or less, on the MAC OS, and I figured that if you had a spreadsheet program that could read/write .XLS or .XLSX files, you’d be good to go.


    • #11172
      elliottdesigns
      Participant

      @tvor-ceasar

      I didn’t realise anyone was using a mac. Sorry guys.

    • #11173
      tvor-ceasar
      Moderator

      @diyaudiphileelliottbridge

      No problem. It served to remind me that it “should” be possible with emulation, so it’s good.


    • #11174
      mumbles202
      Member

      This is a great idea and I’ll definitely keep an eye here. Would be interesting to try my hands at this as well. I built 1 set of the Reveal and actually have all the parts for a second that I never got a chance to build so would be interested to A/B them against the final design here. 

      ?: If I have a pair of ND16FA-6s as well would the physical dimensions of the box be the same and just the crossover be something I’d need to work out separately? 

    • #11175
      tvor-ceasar
      Moderator

      @mumbles202

      The tweeter is a front mount unit with a depth of 0.57″ from face to rear and when mounting to 1/2″ board, it would more or less be flush on the inside due to the lip on the front. So yes, the X-over would be all you’d need to work out.


    • #11176
      123toid
      Keymaster

      @mumbles202

      That is something we are still discussing.  However, if you want it to be the same and just change the tweeter, I can PM you a crossover schematic for the new tweeter in the same size box (as well as placement of the drivers). I worked one up, before we decided to change the enclosure. 


    • #11177
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      That design was sick!  You really know your cad program!  I might need to hire you sometime to teach me some of that.  ALthough< I don’t knwo I have any of the programs you have. 😊 Keep up the awesome work!

       


    • #11179
      123toid
      Keymaster

      @tvor-ceasar

      If I correctly understand the design, I worked something up.  The total box will be about 0.13 cubic feet (7in deep double front baffle, 6in wide and 12″ tall (3″ tweeter and 9″ woofer box). Ported with a 1″ port would be 60hz f3 and could be ported front or rear.  Sealed f3 would be 108hz. LEt me know if I am on point.  What do you guys think of this?

       


    • #11180
      mumbles202
      Member

      @123toid that would be great if it’s not any trouble. I have the tweeter for the Reveal as well but would be curious to try this setup. 

    • #11183
      elliottdesigns
      Participant

      If we are doing a ported speaker I would love to 3D print a flared port for the speaker, it would be nice to contribute something. 🙂

    • #11184
      tvor-ceasar
      Moderator

      Just catching up. I’ve been messing around with the DATS V3, plus I found that REW will work with the Imm-6 Mic. Haven’t used it yet, but I will. Tried WinISD and Xsim – varying degrees of partial success.

      Anyway, here’s what I was thinking of for the first iteration.

      Just starting to use TurboCAD, so the learning curve is steep, but I’m finding where they hide stuff. Now if I can figure out how to do the 3D stuff, I’ll be in like Flynn.

      Oops, just saw I should have rounded the front edges of the tweeter area. There should be enough room to do that and have the tweeter still fit on the face properly.

      This is what it should look like:


    • #11185
      123toid
      Keymaster

      @tvor-ceasar

       The only concern I have with that particular design is how far away the mid range is from the tweeter.  I can’t tell the physical distance from here, not without some type of numbers associated. But anything really over 2.5in  could be problematic.  Most likely come of that tweeters going to need to cross over at a fairly high frequency.  The higher the crossover, the closer the mid range needs to be to the tweeter.  So that might really limit the crossover frequency. 


    • #11186
      123toid
      Keymaster

      I should mention, that my concern resides in both of the designs.  If it wasn’t for near field desktop use, I would be less concerned. But I don’t mind building it that way either way.


    • #11187
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      That would be awesome 


    • #11188
      tvor-ceasar
      Moderator
      Posted by: @123toid

      @tvor-ceasar

       The only concern I have with that particular design is how far away the mid range is from the tweeter.  I can’t tell the physical distance from here, not without some type of numbers associated. But anything really over 2.5in  could be problematic.  Most likely come of that tweeters going to need to cross over at a fairly high frequency.  The higher the crossover, the closer the mid range needs to be to the tweeter.  So that might really limit the crossover frequency. 

      I used 1/2″ for the box thickness, round-overs, and the 45 bevel is based on 1/2″ stock. The face of the upper box is 1/2″ behind the inside face of the lower box. It’s really not that different.

      I liked the way that just about every face for the tweeter is either rounded or beveled.

      Whichever way you want to build is fine.

      For the ported version, if you add in the volume in and around the tweeter, you’ll get closer to 0.15 CuFt, the FB would be about 62 Hz and the F3 will be around 54 Hz, and the 1″ port should be 2-13/16″ long. If you do go for the port, I vote front since they are meant for desktop use. Not sure what kind of bass extension you’d get (if any) for the rear port close to a wall (as most desks are).

       


    • #11189
      123toid
      Keymaster

      @tvor-ceasar

       This is a community build, so let’s do your box.  It’s unique, looks great and will find out if we’re gonna have any negative affects later. But heck that’s part of the fun with building/designing.  


    • #11190
      tvor-ceasar
      Moderator

      @123toid

      Here’s my sketch of the ported version, with the physical offset of woofer to tweeter being closer to 1″. The spacing of the PC83 and the port are more or less by eye, subject to interpretation. I envision the top and bottom box open to each other, providing that slight increase in volume. I found the dimension tool, so there’s that.

      I’d still like to see what others have on their mind for designs. As you can see, I like retro style with modern convenience / engineering. Art Deco is a favorite eye candy.

      Now that I know where the dimension tool is, I can redo the small sealed version if you’d like. I have to work today, but later tonight I’d be able to get to it.

       Anyone else have an idea? Elliot, any ideas? I’d love to see what you can draw up.

       

      *** On my end, I see that the picture can be hard to see, but if you Save it and view directly on your device, you can see it much better.


    • #11192
      elliottdesigns
      Participant

      @tvor-ceasar

      Sure Charlie, I’ll start by doing a 3D model of your design and then testing port flow out of the cabinet to design how the port should bend, how long and wide it should be etc. We can be very creative with how the port looks as well as I am 3d printing it we can make it look really nice and make it fit your art deco theme idea. 🙂 I’ll get to it tomorrow.

    • #11201
      elliottdesigns
      Participant

      @tvor-ceasar

      Just a couple of dimension checks, how thick is it (depth of material/wood) and how large are the chamfers and fillets? Thank you

    • #11202
      elliottdesigns
      Participant

      An interesting comparison to the current midrange/midbass driver could be this Dayton audio ND-90 it seems to have an extremely good spec for a ported design with a really good impulse response, it is a bit more expensive but I find these ND mid-basses have really underrated RMS figures (that is how it seems through testing anyway). I really like their sound signature so if everyone is ok with the price and specs I would really like to recommend it. Thanks, 🙂

      Also, what wood are we planning on using with what finish, or what MDF with what coating (paint, vinyl, etc.)? Thank you all.

    • #11204
      elliottdesigns
      Participant

      Here is a render of your design which has been dimensioned and with the appropriate cut outs and shelling. I haven’t included a port yet as that is still up for discussion in terms of shape size and length. I hope you like it, also any different materials you want to see it is very easy for me to set up so just ask. 🙂

       

    • #11211
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      That looks fantastic!

       


    • #11212
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      If we did a port that has a surface area of 1.5″ circle that is 7.13″ long.  Flare both ends and it should be good. What design were you thinking?


    • #11214
      tvor-ceasar
      Moderator

      Catching up. Obligations, you know. 🙂 

      Elliot, looks nice. I think you saw that everything was 1/2 ” (or whatever size is closest to 12.7 mm), from the MDF to the roundover and the 45 deg. trim. Tweeter = front mount, mid = rear mount. X-over TBD. Currently, the port is 1″ Dia., by 2-1316″ to 3″ long, depending on interior volume (0.15 – 0.13 cu.ft., respectively).

      I’ll have to look at the ND-90.

      To the finish, well, it can be just about anything. I kind of like what Uncle Doug did with this amp. Not necessarily the exact same thing, but the styling cues can be examined. You could even consider that the shape is almost a Southwest Adobe dwelling, so a matte sand or salmon  color might be an option. To me, the enclosure is a blank canvas that can truly be customized to each individual desktop.

      That’s a really nice rendering. Man, I need to get on the stick and learn my personal CADD program. Feeling just a tad “jelly” over your abilities. 😁


    • #11216
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      The ND90’s are great.  I use them all the time.  I agree with the underrated power ratings.  The main issue with the ND series is how hard it is to tame them.  They can be a bear to get the response down for a good crossover point.  Of course, I am probably more of a stickler than most people. 


    • #11217
      tvor-ceasar
      Moderator

      Hah! Simul-posting again!

      Do you know the volume we need to accommodate for the driver? What would that and the port do as well? Unless you build a false bottom to accommodate the port… Or a slot port that would minimally increase the height… Or not. I gotta go to bed. Catch you all tomorrow. 👍


    • #11224
      elliottdesigns
      Participant

      Just done a quick internal volume estimate (drivers and port not used in calculation) for your design.

       Which means it should be between 4 and 4.7L

    • #11225
      elliottdesigns
      Participant

      Just done the box calculations actually, for the nd-90 we can get a -3db point of around 50hz using a slightly curved port without any chuffing, the internal volume doesn’t change the transfer function much at all so should be fine. I’ll try the other driver next. The port is 1.6″ diameter with a 9.55″ length. I would be able to fit it by 3d printing the port if we cant to go ahead with that.

    • #11226
      elliottdesigns
      Participant

      For the PC83 driver, I did a WinISD comparison with the exact same port parameters and box size, and wattage, the bass extension is better on the nd90 driver, as well as the xmax, being 2x larger and the.. well I’ll post the graphs:


      The darker lines are the ND90-4 driver. I am just trying to provide the most information, not trying to be biased. 🙂

    • #11228
      elliottdesigns
      Participant

      Are you guys ok with a 4ohm version instead of 8ohm, the crossover seems to work a bit better.

    • #11229
      elliottdesigns
      Participant

      This is the best I could do for the series crossover circuit for the ND90 configuration (not great, especially for the difference in phase:

      I tried a parallel as well as it would give a minimum 4ohm response somehow, but I’m not good enough with crossovers to get this to work (only good at the mechanical engineering side of things), so even though this midbass would have been a superb alternative, I really just can’t nail that crossover, so maybe just go back to the other driver. 🙁

    • #11233
      elliottdesigns
      Participant

      I know it seems a bit strange but have any of you thought of using a BMR as the tweeter to shift the crossover frequency out of our critical hearing range such as one of these:

      https://www.tectonicaudiolabs.com/wp-content/uploads/2019/09/TEL-DS-TEBM46C20N-4B_Rev-1.4.pdf

      https://www.tectonicaudiolabs.com/wp-content/uploads/2019/08/TEL-DS-TEBM35C10-4_Rev-1.8.pdf

      I used a tectonic 65 in that model I showed you I designed with that rectangular port. I used it as a full-range driver and not only is the frequency range pretty decent for a full-range speaker but because of the lack of a crossover in the critical listening band (well there isn’t one at all) and the sound is so non-directional and natural sounding. I think it might be interesting including one of these drivers, it won’t need as much of an offset either.

      Just an idea, we don’t have to include it, the same as the nd90 or 91.

    • #11236
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      I like the BMR drivers. We almost used one in the Dinas. Let’s stick with the PC 83 for now. We could switch to the ND 90 if you’d like, but I’ll have to get some in. Since these are going to be designed specifically for desktop use, I’d say stick with the four ohm version. 


    • #11241
      elliottdesigns
      Participant

      @123toid

      Sounds great, nd-90/91s would be great if someone could design a good crossover for it. 🙂

    • #11245
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      I said that backwards.  I meant let me get some ND 90’s in and we will switch.  But we’ll have to wait until I can get some in.  I must have been tired when I typed that. Sorry.


    • #11247
      elliottdesigns
      Participant

      @123toid

      It’s all good, I think it was just me anyway. Would you say you prefer the 90 over the 91 then? I wouldn’t know because I have only tested the ND140-4 before and never tried these two out. Thanks, Elliott. 🙂

    • #11250
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      I have never used the ND91.  But I do have experience with the ND90.  In fact, I might actually have some (the Aura NS3).  I forgot they were the same driver.  I’ll have to check to see if I still have some.  The only difference is the color of the cone.  

      The ND90 is a great little speaker.  It is used often in Paul Carmody’s Sprite speaker. Neither of them will have insane bass, but will have a deeper low end. I’ll check to see if I have the 8 ohm version or 4 ohm. 


    • #11268
      elliottdesigns
      Participant

      @123toid

      I think the ND-90 has a bit more of a controlled roll-off as damping is a bit better, I think they coated the aluminium in something. They are extremely similar but one big difference is of course that the Aura you mentioned seems to be 8ohms instead of 4. Also, the 91, is like the 90 but with a longer overhang and more controlled bass reproduction. I didn’t mean about the bass being insane, I just meant low. I don’t like accentuated bass anyway. 🙂

      Thanks Toid, looking forward to seeing how your test turns out!

    • #11271
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      They are the exact same driver. Parts Express often buys speakers like this and puts their name on it. Just like their amplifier boards are made by sure electronics.  They change the color and that’s about it. The TS and everything are exactly the same. They’re a direct replacement. Paul Carmody talks about it in his post above. Don’t get thrown off by the manufacturer’s frequency response graph. Dayton typically does a pretty good job of the response. Other manufacturers though…. Well let’s just say are not always that accurate. 😁

      I believe mine are the 8 ohm version.


    • #11272
      elliottdesigns
      Participant

      @123toid

      Fair enough, I really didn’t know about that. It’s quite interesting, especially as it is much cheaper (I might have to get a few if I can). The 90 and 91 are only 4ohm so there is a little difference as we will have to do the crossovers differently but other than that, looks great. 🙂

    • #11273
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      I think you might be thinking of different drivers. The ND90 and 91 have both a 4 ohm and 8 ohm version. But you’re absolutely right, if someone were to use a different impedance driver or different driver, they would have to change crossover. 


    • #11307
      elliottdesigns
      Participant

      @123toid

      Sorry Toid, you are right. When I searched for them at the time only the 4ohms appeared for whatever reason. I am looking forward to seeing the outcome. How has quarantine been for you? I’ve kept busy preparing for a Solidworks exam I paid for a year back.

    • #11310
      tvor-ceasar
      Moderator

      Been busy as balls here. I’ll pick up again soon.

      Have you had a chance to test the drivers anymore / do any building? Just wondering what to work with for the X-over.


    • #11311
      123toid
      Keymaster

      @tvor-ceasar and @diyaudiphileelliottbridge

      sorry I was crazy busy.  We tore up some flooring and saw a crazy leak that had been occurring since the house was built.  We’ve been hit hard with rain here, so when I got two free days, I worked hard on that.  I plan to build the box this weekend and take the measurements. It is an exciting build.  I am really excited to do this with you guys! 


    • #11314
      elliottdesigns
      Participant

      @123toid

      It’s all good and fully understandable, I didn’t mean to seem impatient at all, I just mistakenly thought you had finished with the leak fixing. As for the two ended 3D printed port, I’ll be printing it in a special ABS, but need to know how many we need, how long we need it, whether we are keeping it circular (or more creative/arty) and how much of a flare we need or want, and of course the surface area of it. Thanks guys.

      p.s. Or are we sticking with what I found for our current dimensions in terms of port parameters from winISD?

    • #11315
      tvor-ceasar
      Moderator

      Seems there’s no rest for the weary. 🙂

      I was just checking in since I’ve been so backlogged. No rush. This helps to keep us all interested and waiting in Antici……………………………..pation!


    • #11413
      elliottdesigns
      Participant

      @tvor-ceasar

      @123toid

      Hi guys, it has been a while now. I was just wondering if you had any updates on testing for the project. 🙂

    • #11417
      123toid
      Keymaster

      @diyaudiphileelliottbridge

      I need to apologize for not updating you guys. My dad went into the hospital and I put this on the back burner while that was going on. He is out now, so I am getting back to normalcy.


    • #11418
      tvor-ceasar
      Moderator

      I hope all is better with your dad and it was nothing permanent. Family first. 

      Whenever you get to it is fine for me. I’ve been busy straight through all this and things are picking up even more, so… at this point, I’m just curious what they’d sound like with just a single high pass cap on the tweeter, say maybe a 15uF. That’d put it at about 2650 Hz. Just for a start.

      Whenever it happens, just let us know. We’re here and not going anywhere.


    • #11441
      tvor-ceasar
      Moderator

      Did a bit of looking at the drivers and my quick suggestion above. Threw them in XSim and scrolled the value up and down, and it looks like the value I picked was the best available via PE’s Cap page.

      So, this is just a starting point. Anyone else have a suggestion?

      My only concern about much more complex designs is that they will most likely reduce the output of the PC-83, which will necessitate the attenuation of the ND16FA even more than the graph shows is needed. Of course, these are for desktop / nearfield and they are rated for 30 Watts, so there’s that.

      Also, I don’t like the way that XSim plots the PC-83 falling off when it’s connected full range. Maybe I’m missing something.


    • #11446
      123toid
      Keymaster

      @tvor-ceasar

      I think we are switching to the ND90-8 from the PC83-4.  This will make it more versatile.  I plan to make the box this week.  MY wife works weekends, so I don’t get to work on projects during this time.  I watch the kids instead 🙂 


    • #11447
      tvor-ceasar
      Moderator

      Switching to the ND90-8 will drop the bottom end a good bit, FB ~63 Hz and F3 ~59 Hz, assuming the same 0.09 Cu.Ft. box. Port will change, but we can discuss that too. I’ll have to download the files and re-run the simple X-over, but I can see the tweeter will need some attenuation, as it’s about 12 dB louder.


    • #11448
      123toid
      Keymaster

      @tvor-ceasar

      I’ll make sure to get the z offset and the anechoic chamber files for you guys as soon as I build the box. That way we can get an accurate representation of what it’ll do.


    • #11452
      tvor-ceasar
      Moderator

      Simplest I could come up with that flattened out the massive hump of the tweeter vs. the full range. A little under $4 per speaker at PE. And yes, the tweeter is reversed. Looked real ugly in the normal position. And a lowpass on the Full range really didn’t do anything to help, so why add complexity where it’s not necessary.




    • #11655
      123toid
      Keymaster

      I really want to apologize for this being put on hold.  This was not my intention.  I didn’t tell anyone, but my father got really ill and was in and out of the hospital.  THen we found out my brother in law was being deployed for an entire year.  So I helped him out, jsut getting his families new house (they just bought) ready.  THat way his family shouldn’t need anything while he is gone.  But I am back and will get started on this in about a week.  I have a few other designs that I am finishing up.  I’ll post some of them on here, including a $3,500 Home Theater speaker clone for about $350. I am in the process of finishing the design of those those. 


    • #11656
      tvor-ceasar
      Moderator

      Health and family first. You can’t give a hobby/passion (even if it might bring income) the attention it deserves if you are divided over much bigger worries. Especially in the climate of today. To quote Charles M. Schulz, “You’re a good man, Charlie Brown.”

      I do hope your father is better and better every day and that your brother-in-law comes back safe and whole.

      Whenever you get around to the build is ok by me. I’ve got a lot to do in the next 2 months before I start the journey to a new me. That starts mid October, so hopefully by then I’ll be better able to participate.


    • #11657
      pwarren3030
      Participant

      I just found this thread. But I fear I’ve missed something. What is the aim of this speaker? Eg main speakers? bookshelf, bedroom, size, cost? You know all that basic stuff. Cheers Peter in Sydney.

    • #11658
      tvor-ceasar
      Moderator

      Currently, the goals are desktop use, preferably with an accompanying sub, such as the Mini Earthquake, designed by 123Toid. The beginning of this thread gives the generalities, but there is a point where the decision was made to change from the PC83 to the ND90, mostly because that is what is on hand. It’s a good driver, just a bit lower output. Should be interesting once we get back into it.

      Go ahead and start at the beginning to catch up. I welcome any and all input. This is, after all, a community build. Glad you could join in. Can’t wait to see what your thoughts are.

      ***By “I”, I mean we. After all, we are a small but growing family.


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