Announcement

Collapse
No announcement yet.

Making my AviaTrix MLTLs

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Making my AviaTrix MLTLs

    In 2001, 16 year old me started a hobby of speaker building by building a sealed enclosure for two 12" JBL LC-S1250w subwoofers for my '85 Jeep Cherokee (overkill, anyone?). Last fall, I build the ported Tritrix MTM bookshelves for my brother, then the ported Overnight Sensation TM for my cousin—both are extremely happy with the results. I also built a boom box for a buddy, called the Sope Box. After those successes, I decided I had gathered the skill set to make a pair for myself that I wouldn't be too self-critical on: the AviaTrix. I love how the Tritrix sounds, and for as small of a living room as I have, I don't need much SPL-wise. I don't really even play my music obscenely loud, anyway ... unless it has a good bass track. Then you have to crank it to 11, of course.

    I'm just going by the books for the MLTL version using parallel 12.5Ω and 10Ω resistors on the tweeter net and the 3" Precision Port. Enclosure is 3/4" MDF all around with one or two window braces (just two square windows, not four), and I'm going to laminate a 1/2–3/4" thick piece of nice hardwood—yet to be sourced—on the baffle section where the drivers are. The hardwood will stop about 4" under, and radiused to match, the lower ND140-8. I'm not sure if I'll do the same for the port, but if I do I'll match it on the rear for the terminals and extend the width so they act as small outriggers.

    So this will be the start of my living room, even though I rent a house and can't do major construction. They will be used as L/R, with a sealed AviTrix for center channel and ported AviaTrix MT for surround. I'm planning on building the Digger8 for HT duties—it will be turned off for music as I prefer two-channel.

    The crossovers are done, and compared to the other two designs I've built it was no problem. Sorry for the low-quality snaps... when the D90 is charged, and when actual progress is made, I'll post more.

    Click image for larger version

Name:	20140717_002031.jpg
Views:	1
Size:	581.6 KB
ID:	1189491

    Click image for larger version

Name:	20140717_002020.jpg
Views:	1
Size:	504.9 KB
ID:	1189492

    Everything driven by a Pioneer VSX-820 receiver ($110 on Craigslist!)
    Click image for larger version

Name:	20140717_002101.jpg
Views:	1
Size:	456.8 KB
ID:	1189494

    The sadness and current setup: white van speakers (London Audio!) and half of that old sealed box with the same ole JBL LC-S1250w from long ago, driven by a plate amp pushing 180W. After "testing" the Tritrix and OS speakers for months and having to finally give them to their respective recipients, it seems like a shame! BOTH of those designs sounded awesome in my small living room... I wonder how the AviaTrix MLTL will match match up?
    Click image for larger version

Name:	20140717_002041.jpg
Views:	1
Size:	456.5 KB
ID:	1189493

    I'd like to extend a sincere thank you to Curt Campbell and Paul Carmody for designing the speakers I've built so far: they've opened my ey....ears.

    My 29 year old bachelor pad living room: basically a 15' x 11.5' area, minus 5' x 3.5' for the bathroom directly to the right of the TV. The room is open on the right by a wide doorway to the kitchen and above the TV to the staircase. Ceilings are 8'. The area immediately the left of the left speaker is open to the front door/staircase, and the right speaker is flanked by the bathroom door.
    Last edited by JoshuaC2U5H; 07-17-2014, 04:29 PM.

  • #2
    Re: Making my AviaTrix MLTLs

    Excited to watch your build come together!

    Comment


    • #3
      Re: Making my AviaTrix MLTLs

      Thanks Matt—I'm more excited, I guarantee it!

      I've been burning in the drivers just running at low volume (L/R channels on AVR set to "small," crossed over at 100 Hz). I think I'll have these done in two or three weeks, so next week I'll change the AVR to "large" and allow some more bass through to the ND140-8s... let that spider epoxy get nice and loose for the debut! We're talking low volume, no LFE movies or anything. Little bit of random music thrown in.

      I was thinking more about what kind of hardwood I want to use for portions of the baffle, and I think I settled on purple heart. Dense, beautiful, different. Tung oil finish (unless guided otherwise). Any thoughts on this?

      Comment


      • #4
        Re: Making my AviaTrix MLTLs

        I think the problem with an oil finish on purple heart is that it won't keep its purple hue. Might be worth searching on some wood working forums for some ideas on what the result would look like.

        Comment


        • #5
          Re: Making my AviaTrix MLTLs

          Originally posted by knowledgebass View Post
          I think the problem with an oil finish on purple heart is that it won't keep its purple hue. Might be worth searching on some wood working forums for some ideas on what the result would look like.
          I've also thought about doing crystal clear shellac + sanding (3 coats) + basic clear lacquer. Endgrain would receive extra sanding at a grade or two above the rest based on research.

          Comment


          • #6
            Re: Making my AviaTrix MLTLs

            Got the enclosures roughed out, but still need to make and install the two window braces in each tower. Don't ask me why I didn't have them in there already before I put the other side board on. I don't know.

            Click image for larger version

Name:	20140719_212245.jpg
Views:	1
Size:	436.6 KB
ID:	1159258
            Attached Files

            Comment


            • #7
              Re: Making my AviaTrix MLTLs

              Got the four window braces roughed out--just gotta run the 3/4" roundover bit around all the edges and sand, then install.

              Click image for larger version

Name:	uploadfromtaptalk1406424428065.jpg
Views:	1
Size:	30.5 KB
ID:	1159395

              Also picked up a Dual 1009 turntable ($40 on Craigslist!) and the 3/4" purple heart boards for the baffles under the drivers and port.

              Click image for larger version

Name:	uploadfromtaptalk1406424437859.jpg
Views:	1
Size:	69.1 KB
ID:	1159396

              Click image for larger version

Name:	uploadfromtaptalk1406424447060.jpg
Views:	1
Size:	42.6 KB
ID:	1159397
              Last edited by JoshuaC2U5H; 07-27-2014, 07:43 PM.

              Comment


              • #8
                Re: Making my AviaTrix MLTLs

                More progress today...

                Ended up doing 1/2" roundover on the braces because I didn't have a 3/4" one, haha. Silly gansito. Hand sanded afterwards. A lot of effort put into them even though I'll be sealing the enclosure up for no one to see!

                Click image for larger version

Name:	20140727_094219.jpg
Views:	1
Size:	417.4 KB
ID:	1159409

                Click image for larger version

Name:	20140727_100047.jpg
Views:	1
Size:	412.1 KB
ID:	1159408

                Click image for larger version

Name:	20140724_184752.jpg
Views:	1
Size:	306.0 KB
ID:	1159410Click image for larger version

Name:	20140727_134135.jpg
Views:	1
Size:	291.2 KB
ID:	1159411

                Click image for larger version

Name:	20140727_144057.jpg
Views:	1
Size:	347.7 KB
ID:	1159412

                Comment


                • #9
                  Re: Making my AviaTrix MLTLs

                  Another of the braces

                  Click image for larger version

Name:	20140727_132549.jpg
Views:	1
Size:	301.5 KB
ID:	1159413

                  Got the bottoms of the 3/4" purple heart baffles routed how I like. 7.5" diameter arc.

                  Click image for larger version

Name:	20140727_170833.jpg
Views:	1
Size:	402.5 KB
ID:	1159414

                  Comment


                  • #10
                    Re: Making my AviaTrix MLTLs

                    Quick mockup (port portion will have radius on top to match)
                    Click image for larger version

Name:	uploadfromtaptalk1406680228496.jpg
Views:	1
Size:	37.3 KB
ID:	1159483

                    Comment


                    • #11
                      Click image for larger version

Name:	20141206_170131.jpg
Views:	1
Size:	531.1 KB
ID:	1162590

                      Click image for larger version

Name:	20141206_170308.jpg
Views:	1
Size:	530.8 KB
ID:	1162591

                      Comment


                      • #12
                        Re: Making my AviaTrix MLTLs

                        I like the AviTrix plans.
                        Haven't seen many builds .
                        Will be watching this one, can't wait to hear how you like them.
                        They're looking good so far.

                        Comment


                        • #13
                          Re: Making my AviaTrix MLTLs

                          Thanks Dew, I appreciate it. I chose the Avi since I had already built and loved my brother's vented TriTrix bookshelves but wanted to change it up and upgrade a bit, too. I also have barely seen any build of it—seems a shame that Curt and Paul put all that work into its design. I love the ND140-8's capless cone and large rubber surround, and their silver metallic color will go great against the contrasting Purple Heart.

                          I only wish I could have heard them before I built—being in central MD, I don't seem to have a lot of DIYers around, or any local meets that I can find.

                          Comment


                          • #14
                            Re: Making my AviaTrix MLTLs

                            Wow.

                            So I guess there's a positive to having months in between builds: going back to crap speakers in the meantime makes the reveal of the newly-built speakers more extravagant and impressive. I just hooked the Aviatrix up yesterday morning and spent all day fiddling and listening. They would have been up and running Saturday, but I snapped two steel wood screws off in the Purpleheart trying to mount the drivers ... this wood really is a bitch to work with. The holes for the hardware were predrilled, too, almost too big, and they still snapped the heads off.

                            Working with an exotic, dense, gummy hardwood ain't all it's cracked up to be, especially in my lightly-equipped shop. A fixed speed, 20 year old router meant my bit speed was way too fast, burning bits/wood which made the Purpleheart gummy, using bits that weren't perfectly sharp which didn't compliment the blazing fast bit speed very well, and generally just not knowing what I was getting myself into. My brother had worked with it in his knife making for handle material, but nothing of this scope: his warnings were too light-hearted.

                            But they came together, and they sound FANTASTIC!! I'm getting a good amount of detrimental "boominess" in the 80-200 Hz department (not measured, just using iTunes EQ), but with that region attenuated a bit, the bass sounds very clear and concise. My GF and some friends that auditioned them were pleased with their performance—I, on the other hand, am ecstatic.

                            So to fix my boomy bass problem, here is where I'm starting:
                            • Near wall placement with about 6" of space available to move out
                            • Running off 100 W receiver (Pioneer VSX-820) in Large mode, no EQ, crossed at 50 Hz (I'm unable to turn the crossover completely off, have to investigate)
                            • Stuffing is on the light side, about the same density from the top until about 12" from the bottom of the tower, where is it open with no stuffing
                            • All test albums are 320 Kbps or better MP3 and some FLAC uncompressed stuff, too: Last of the Mohicans soundtrack, Daft Punk "Discovery", Jethro Tull "Aqualung", Tommy Emmanuel "Endless Road", The Infamous Stringdusters "Let It Go", Delta Spirit "History From Below" ...
                            • Listening environment is mostly hard surfaces, unfortunately: hardwood floors with a small area rug under couch, room is medium sized (~10 x 12 ft) with 8 ft ceilings, open to kitchen and stairway

                            Things I'm going to try:
                            • Bring speaker out from wall (already tried with no improvement, not much change in sound, can't keep pulled away from wall for extended periods due to space)
                            • Add more stuffing, try stuffing different ways. This is were I think the most change can be made: I pulled all the stuffing fairly loose before putting it inside, so I think the overall density could be upped a bunch, especially behind the drivers. I also kept the density fairly uniform from top to bottom, and I've read that decreasing the density while going down the TL is best, with very little to no stuffing in the crossover/port section at the bottom. I'll just have to experiment with this.
                            • Fiddling with the EQ/receiver some: I could have a setting that's a bit off on my receiver

                            Things to finish on the towers:
                            1. Add a 1/2" or 3/4" roundover to the rounded and vertical edges of the Purpleheart portions of the baffle
                            2. Flush mount the ports and ND140-8s
                            3. Seal the Purpleheart
                            4. Paint the MDF portions; still undecided on surface texture and color
                            5. Add 1-2" to overall height using feet or something

                            That's pretty much it! Enjoy some horrible cellphone pictures of them in rough form:

                            Click image for larger version

Name:	20141215_091023.jpg
Views:	1
Size:	332.8 KB
ID:	1162735

                            Click image for larger version

Name:	20141215_091042.jpg
Views:	1
Size:	683.0 KB
ID:	1162736

                            Click image for larger version

Name:	20141215_091055.jpg
Views:	1
Size:	696.5 KB
ID:	1162737
                            Last edited by JoshuaC2U5H; 12-15-2014, 03:41 PM.

                            Comment


                            • #15
                              Re: Making my AviaTrix MLTLs

                              Nice job! I like how you did the contrast between the upper and lower purple heart baffles over the boxes.

                              From my limited knowledge/reading, your symptoms sound like not enough stuffing density... I think many TL designs use a density of 0.75 lb/ft3 over the first 2/3 of the line... which is actually quite a bit of stuffing.

                              Comment

                              Working...
                              X