NaO Note II RS CNC Build

danvprod · « **on:** 7 Nov 2016, 02:37 am »

I'm building a set of NaO Note II RS open baffle speakers. My aim is to document the process here. The NaO Note II RS speakers are a TM design by Music and Design. Please purchase the plans from John K if you are going to build them. The decision to build these are based on much research. Considering the alternatives and competition, I've decided that these are the best design for my room. I hope I am right.

My listening room is 16'3" x 13'6" x 9'0" tall. I'm building this version with the help of my friend who has a CNC router, which greatly simplifies the cutting out of the baffles, the most complex part of this build.

The components of the speakers include (per speaker):
1) A pair of Peerless by Tymphany OX20SC00-04 3/4" Fabric Dome Tweeters.
2) A Scanspeak 22W/8534G00 Discovery 8" Woofer.
3) A Scanspeak 10F/4424G Discovery 4" Midrange.
4) A pair of Peerless by Tymphany SLS or XXLS 10" subwoofers.

The speaker requires 4 or 5 channels of amplification and a MiniDSP 4x10 HD.

I already have the MiniDSP 4x10 HD and I just purchased a Crestron CNAMPX 12x60 amplifier, which turns out to manufactured by ATI in the USA, and available a price that is almost too good to be true.

I have to figure out the best way to wires these up, with 5 channels coming from the amp. Considering a snake cable terminated to a SpeakOn 8-pin connector.

So far, we've figured out the tool path for the baffle, which I will cut out first with MDF and then eventually solid 3/4" walnut. Hopefully this build will be useful to others considering making these awesome and well-designed open baffle speakers.

More to come...

poseidonsvoice · « **Reply #1 on:** 7 Nov 2016, 02:51 am »

John Kreskovsky has a good head on his shoulders. I've listened to his designs in the past and have been pleased compared to commercial designs. And I've listened to the SL Orion, Pluto, LX521 and LX Mini series, all were fine designs and are the primary speakers many will compare to when looking at Kreskovsky's work. But John has a few things up his sleeve including the implementation of small waveguides to assist in pattern control.

Too bad you have a square room but the 9ft ceiling helps.

Looking forward to your build log

Music & Design: http://www.musicanddesign.com/naomain.html

Best,
Anand.

richidoo · « **Reply #2 on:** 7 Nov 2016, 05:00 am »

Looks cool! I will follow your progress here.

danvprod · « **Reply #3 on:** 7 Nov 2016, 02:20 pm »

I should add, and should have made this clear from the start. This is a trademarked design of John K from Music and Design. You can read about the speaker on his website: http://www.musicanddesign.com/NaO_Note_II_RS_Details.html. I have licensed his plans. This thread is more about building this speaker, going from the plans to a CNC-realized version and my system setup with the speakers.

I'm looking for ideas and opinions on the following two topics:

1) How best to wire up the speakers?

I plan on going from my 12-channel amp to the speakers with 5-channels, powering each woofer independently. My thought was to run a 8-conductor cable terminated to a speakON NL8FC for the tweeters, upper midrange and lower midrange. And then a high-gauge 4-conductor wire terminated to a speakON NL4FC. I won't need all 8-conductors of the NL8, just 6. And then on the other side of the cable, have banana plugs to plug into the 10 channels of the amp.

2) Should I build these with the standard SLS woofers, or go all the way with the XXLS woofers? The SLSs are $271 for the 4 from PE, with the possibility of a coupon coming up soon. The Peerless 835016 XXLS 10" Aluminum Cone 4 ohm woofers are $231/each for a total of $924 for the 4. Total cost of drivers with the XXLSs are $1350, all from Madisound.

My Crestron CNAMPX should be coming on Friday, and I hope to have more to report on the cutting of the front baffle.

John K makes a good point about the XXLS vs SLS. The difference in price is $653. That is certainly enough to add a powered subwoofer or two. Although something about the simplicity of a single pair of speakers without subwoofers are desirable as well.

danvprod · « **Reply #4 on:** 8 Nov 2016, 03:10 pm »

We started the process of cutting out the baffles for the build. For this first test, I am using some scrap MDF to make sure the cut is working out.

The CNC being used is a Shapeoko XL Kit: https://shop.carbide3d.com/collections/machines/products/shapeoko-xl-kit?variant=15826339270

This machine gives me a cutting area of 33" x 17" x 3". This is big enough to cut the baffles, but too small for the sides, so I am going to have to be creative in cutting out those pieces. The designs are being drawn in Adobe Illustrator and the tool paths realized in Carbide Create. A couple of learnings from the draft cut:

1) Pick your feed rate carefully. I started at 75" (default). Way too fast. 20" for 3/4" MDF is a good compromise. Cut depth is 0.05", which may be a bit conservative. I'll have to continue to experiment here.

2) Carbide Create is easy to use, but some things are tedious right now (the software is in beta). You can't mass-edit the feed rate or cut depth on all paths, for example. That is a challenge. Although once this is set up and locked down, it should be good to go for the final cuts.

Here is a picture of the CNC getting started on the cut:

I'm still planning on doing the tweeter roundovers (1/2" radius on the front and back of the baffle), driver roundovers (back; 1/2" radius), and baffle roundovers (3/8" radius, front and back) manually using my hand router vs. doing this on the CNC. I am also planning on drilling pilot holes for the driver mounting during the CNC cutting process, to simply the assembly.

matevana · « **Reply #5 on:** 10 Nov 2016, 02:07 pm »

Your thoughts on the 4 and 8 conductor Speakon pole connectors should work well and will keep things as orderly as possible. Rather than using two separate multi-conductor cables, I would suggest individual strands of teflon covered silver coated copper wire that you can bundle as one wide diameter cable in tech flex sheathing. You may find this has several advantages; one would be varying gauges for each of the intended drivers. The Speakon connectors can be a little trying to terminate neatly, especially with a heavy gauge multi conductor cable. I've run as many as 12 separate strands of teflon wires in 3/4" tech flex and it looks and sounds great. The stranded wire is sold in many gauges, is relatively inexpensive, and can be purchased by the foot on eBay.

danvprod · « **Reply #6 on:** 10 Nov 2016, 10:31 pm »

Thank @matevana -- that is a great idea. I actually found and am watching some 5-conductor cable: PTFE covered silver coated color coded wire on eBay. A pair of runs of this material will get me there for each side. It's 16 AWG. And then maybe using twisted pair cable for the hookup within the speaker might work.

Have the draft baffle cut out now. There are a couple things that I need to change in the tool path. The recesses for the upper and lower mid are reversed and surprisingly everything is not as straight as I would have expected it to come out. So some further exploration there.

danvprod · « **Reply #7 on:** 10 Nov 2016, 10:46 pm »

Here is a closeup of the tweeter pocket cutout:

JohnR · « **Reply #8 on:** 11 Nov 2016, 04:47 am »

Cool

danvprod · « **Reply #9 on:** 11 Nov 2016, 11:58 pm »

The amp has arrived! Glad the seller double boxed it because FedEx trashed the outer box. These Crestron CNAMPX 12x60s (and 16x60s) are interesting little amps. The build quality is amazing. They are ATI all the way and you can tell. Trick is you need to provide +24v power to the CresNet to get them to operate. I ended up purchasing a proper Crestron 24v power supply along with the amp. Should work perfectly for my use-case. If you don't have them on a Crestron system, you do need to press the bypass switch on the back and then all channels will work. This thing is a beast.

jzexport · « **Reply #10 on:** 16 Nov 2016, 08:09 pm »

Congratulations on your choice and good luck with your build.

I built a pair earlier this year and am very happy with the result.

A CNC machine would have been nice. I made a set of templates for the upper baffles from 1/4" MDF to use as a guide for the router. I made the baffles from 3/4" walnut veneered plywood.

I chose the XLS woofers, just for peace of mind. My guess is that they aren't really necessary. There is zero issue with sufficient bass response.

For the speaker cable, I used ProX speaker cable that bundles 8 12 AWG OFC copper wires into a single cable. So, only a single cable goes from the amps to the speaker. I hard wired the cables at the speaker end, i.e., there are no intermediate connectors at the speaker. You can get an idea of this by looking at my post on diyaudio.com:

http://www.diyaudio.com/forums/multi-way/289361-nao-note-ii-rs-completed-march-2016-a.html

My amps are two multichannel Lexicon LXs with 200W per channel. I doubt I use a fraction of that.

Josh

danvprod · « **Reply #11 on:** 17 Nov 2016, 07:28 pm »

Thanks, Josh. I did find your build thread on DIY. Your finish is beautiful, the nicest I've seen of the Notes built to date. Did you veneer over MDF? It's hard to tell from the pictures. I see you also used Kreg pocket-holes -- I was planning on doing that as well.

BTW, here is the CNC cut paths for front and back, I thought it was pretty cool:

Yesterday I made some good progress -- I built the 10 conductor cable and tested out the amp on a small full-range loudspeaker. Everything is working as expected. The result is a single cable connecting the amplifier to each speaker. Should be a clean install. The cable is wrapped in tech flex and covered with heat shrink tubing at the ends. A bit worried that 16 AWG is a little light, but we will see.

mcgsxr · « **Reply #12 on:** 17 Nov 2016, 08:16 pm »

Every time I see excellence like this, I get even more embarrassed by the raw mdf panels I ran for 10 years!

Great stuff, and thanks for sharing.

danvprod · « **Reply #13 on:** 17 Nov 2016, 08:52 pm »

I started my open baffle journey the same way just over four years ago. I started with a pair of Bestys on big hinged baffles and fell in love with the open baffle sound. However, they were big and didn't fit in my listening room well so I quickly started doing more research. That is when I found AC and the works of MJK.

I moved on and experimented with adding a pair of Alpha 15s and ran Betsys above A15s on a flat baffle. At that point I also found the MiniDSP. This was better but still needed improvement. I played around with putting the Alpha 15s in H-frames and also tried Mark Audio 10Ps on flat baffles for even a better result.

Then I experimented a bit with high-efficiency horns -- I sold the Betsy, Alphas (still in their H-frames) and 10Ps and invested in some JBL pro gear: 2445J 2" compression drivers, 2405 Super Tweeters and 15" 2226 LF drivers. I've been running that system for the past three years. But now I'm ready for a new challenge and I've always missed that special OB sound. It's been a fun journey and I hope that these NaO Notes don't disappoint, and I suspect that they won't.

And now it's time to sell the JBL gear and move on to something else. That's what is fun about this DIY journey -- the journey. It's awesome to build something and learn all of the skills in the process. DSP design and configuration, woodworking, electronics, soldering, driver selection, speaker design. And find out what I like and what I don't like. I'd never have all the skills I have now if I purchased a set of commercial loudspeakers. Not even close.

danvprod · « **Reply #14 on:** 17 Nov 2016, 09:07 pm »

Here is the dry fit of one of the speakers in profile:

danvprod · « **Reply #15 on:** 17 Nov 2016, 09:25 pm »

Had a better thought about cutting this out. This simplifies the cut and lets me lock the material down better over the cut front and back.

Basically, the first step is cutting out the front holes and rabbits for the drivers. Then I flip the stock and cut out the tweeter pockets and finally cut out the through cuts. This will hopefully obviate the need for doweling.

I'll report back tonight.

poseidonsvoice · « **Reply #16 on:** 18 Nov 2016, 01:21 am »

Quote from: danvprod on 17 Nov 2016, 08:52 pm

I started my open baffle journey the same way just over four years ago. I started with a pair of Bestys on big hinged baffles and fell in love with the open baffle sound. However, they were big and didn't fit in my listening room well so I quickly started doing more research. That is when I found AC and the works of MJK.

I moved on and experimented with adding a pair of Alpha 15s and ran Betsys above A15s on a flat baffle. At that point I also found the MiniDSP. This was better but still needed improvement. I played around with putting the Alpha 15s in H-frames and also tried Mark Audio 10Ps on flat baffles for even a better result.

Then I experimented a bit with high-efficiency horns -- I sold the Betsy, Alphas (still in their H-frames) and 10Ps and invested in some JBL pro gear: 2445J 2" compression drivers, 2405 Super Tweeters and 15" 2226 LF drivers. I've been running that system for the past three years. But now I'm ready for a new challenge and I've always missed that special OB sound. It's been a fun journey and I hope that these NaO Notes don't disappoint, and I suspect that they won't.

And now it's time to sell the JBL gear and move on to something else. That's what is fun about this DIY journey -- the journey. It's awesome to build something and learn all of the skills in the process. DSP design and configuration, woodworking, electronics, soldering, driver selection, speaker design. And find out what I like and what I don't like. I'd never have all the skills I have now if I purchased a set of commercial loudspeakers. Not even close.

You are absolutely right! It's about the journey not a destination. Keep it up, I'm enjoying this thread as I had (once) toyed with the idea of building John K's designs.

Best,
Anand.

jzexport · « **Reply #17 on:** 18 Nov 2016, 01:36 pm »

I used 3/4" pre-veneered poplar-cored plywood. It cost about $120 for one sheet, which is all that is needed. It comes in many choices of veneer. My only complaint is that it is somewhat lightweight. For the flat edges, I used pre-glued iron-on veneer edge banding, even on the sweeping curved edge of the side baffle. Very easy. On the rounded over edges for the driver cutouts and the upper baffle, I used closely matching paint.

The pocket holes were the suggestion of the wood working friend who helped me. I think they were a very good idea and since he had the jig, drill bits and screws it was an easy decision. We used them at every joint possible.

I cannot comment on 16 gauge wire. I am not a believer in specialty cables, but the lower the resistance the better. Without knowing the current draw, cannot say.

Why are you using 5 pairs of cables?

Josh

danvprod · « **Reply #18 on:** 18 Nov 2016, 11:14 pm »

Josh -- thanks for the info on the plywood. I'm planning on painting mine black, so the birch ply is not so big of deal, but yours sure do look nice. I am not a big believer in high-end cable either. My runs are short -- about 7' and having each speaker driving with a single pair of cables ought to keep the resistance low. We will see.

I am running each woofer on a separate channel of my 12-channel amp. This should let me give each woofer a separate 60 watt amp. My amp is a bit on the low-end of wattage that John recommends, and I had the channels available, so he recommended wiring it up this way.

danvprod · « **Reply #19 on:** 21 Nov 2016, 06:15 pm »

Done! (Well sort of.)

I put together the speakers this past weekend and put all the drivers in to test if everything is working. I still need to build the grills and paint the cabinets. I also need to mount the tweeters permanently (right now I am using blu-tack). And I need more flexible hook-up cable as the ones that I am using now is causing some rattling. This will also be fixed once I zip tie the cables to my mounting hardware.