Nova Monitor

edit: This thread was originally for a build using the madisound aura ns6 kit

see post #13 for updated details

 

http://www.avsforum.com/t/1393595/nova-monitor#post_22294821

Edited by Jay1 - 8/9/12 at 11:23pm

Cut and flush trimmed using a dremel with it's circle guide attachment!

Gluing up some 2" ABS pipe for the port before I start gluing panels together.

Edited by Jay1 - 8/9/12 at 9:09pm

In keeping with the cheapo theme I didnt bother with cutting/routing/rounding an inner radius for the port. I drum sanded by hand with my dremel a rough radius, then smoothed by hand with 180. The ABS is 3/16" thick. It's minimal, but better then nothing and took 10 minutes. Got the sides and back glued up on one, dont have enough braces for both

Work on these has slowed considerably, but I've managed to make some solid progress. I flush trimmed all sides, then glued up the top and bottom panels. I've read threads recently on various forums bashing PL Premium for not curing (some have made a big deal after only 12 hours). I've never had a problem with it, but during this last use I definitely experienced the claims. The difference is, I know my tube was good so I gave it time, 3 days to be exact for it to fully cure. The temp had dropped significantly, and the humidity with it, so that's what I blame this whole fiasco on. Verdict is, dont rush with PL. After that cured I decided to add some bracing, which honestly isnt even need considering the box size and 3/4" ply.

I've got the front to back brace tied into the port with a line of PL, and there's another brace under the port tying into the bottom. I have a 45 degree angle brace I'll be adding to the top. I've really got to start thinking about bracing before I glue up the sides... Definitely getting extensive with the bracing on the center channel I'm doing next.

Got the boxes flush trimmed. I need to get some more 120 and sand these things down real good before I put a 1/2" round over on them. Hopefully I'll remember to pick up the 120 tonight.

Got a chance to work on these for a few hours today.

Sanded down then ran a 1/2" round-over bit. I guess I lucked out with my baffle width, as I dont think I could have got much closer to the woofer cutout. You can see the void issue I have here as well



This is on top of one of the cabs I should have been able to prime tonight, instead I'll be spending days fixing this crap plywood.



First application of bondo for my largest void. It'll most likely take at least 3 trys to fix it up


Of course I cant say when I'll be free to work on them again

I got the majority of the voids taken care of, but it seams like random areas keep breaking off. I'm going to try something new for myself, I mixed up water/wood glue and rolled a couple coats on with a paint roller. Hopefully it seeps in and seals/hardens the exterior plys. Not quite sure how it will act with the bondo'd areas? Guess I'll be the one to find out.

The glue/water worked really well, even over bondo. I only did one more application of bondo after sealing, I'm starting to get anxious to finish these. I drilled all the hardware holes then set up for painting.

All I had on hand was a can of the rustoleum primer, which I hate, but I really wanted to get this going tonight. Hopefully I'll get these top coated on tuesday.

Got these top coated! After they cure I can begin installing all the internal components, and hopefully have surround sound again this weekend!

I "scuffed/buffed" the primer with soapy water and a green scotch brite pad, since I decided to spray something other then flat I wanted the surface really smooth. I went with the krylon satin nickel this time, I wanted something similar to my wall color, but not as boring as egg shell white. They look pretty good from a couple feet, up close you can see all the voids I missed on the ply wood. Best thing about DIY is it only has to be good enough for me, which is why i didnt backfill and re prime lol.

Done! Got everything wired up and installed late last night, didnt get a chance to listen until this morning. Tried them out as monitors just to make sure everything works right, they sound good! Without my subs on bass was of course missing, as these dont really go below 80hz. Sound was very smooth and clear, with solid imaging. Cant go wrong for how much these cost!

Kit - $95
2pr binding post - $15
2 cans satin nickel paint - $7
2pr wall mount hangers (3pk) - $3
Screws - $5
spray adhesive - $5
wood - free, left over
glue - free, left over
wire - free, left over
Primer - free, left over
polyfill - free, left over
mattress pad - free


total $130 pr

Still have to wire and mount, I plan on placing some felt pads over the wall hangers just to make sure they dont rattle.

DISCLAIMER: This design was created using the PCD simulated measurement process, you can read more about it here
https://sites.google.com/site/undefinition/simulated-measurements

The madisound kit worked fine for surround use, it is clearly not an optimized design. I have since learned how to design xovers through simulation. This is my attempt at a near wall monitor design, and surround speaker. Off axis response has been highly optimized, according to simulations response is within 2 db out past 80 degrees horizontally and up to 15 degrees vertically. The rolloff below 1khz is intentional to allow near wall placement for surround usage, or as monitors in a less then ideal locations. The phase integration is extremely good between drivers, even well past the xover point. The woofer has a minor peak at 4.3khz, which was actually showing up in the tweeters response due to the phase integration, a notch filter was added to the crossover due to this. The woofers TS parameters were also completely off from what has been measured, this created a hump in the low end response that required some shaping within the xover, it also means these dont go as deep as originally planned. 80hz isn't an issue with near wall placement.


(This design should be sealed if used as on wall surround)



Impedance is very good, even with a 4ohm tweeter it never dips below 5 ohms, and is very high throughout the woofers range.


A + brace front/side below the woofer is all that is needed for these small cabs.



If anyone wishes to build this, inductors must maintain the same DCR values, but all other components can be changed based on your preferences


Aurasound NS6-255-8A $9 $18
http://www.madisoundspeakerstore.com/approx-6-7-woofers/aurasound-ns6-255-8a-paper-cone-woofer-8-ohm/
Vifa DQ25SC16-04 $23 $46
http://www.madisoundspeakerstore.com/hard-dome-tweeter/vifa-dq25sc16-04-1-titanium-dome-tweeter/


This is where I am at, I should be receiving the xover components next week and post an update when complete
Edited by Jay1 - 1/14/13 at 9:55pm

Got everything installed, and have had a bit of time to listen and compare. The off axis response is definitely very good, moving around, standing up, didnt shift much of anything. Bass is light when placed up on stands away from boundaries, with the subs on it wasnt an issue. I placed them in a "less then ideal" location for most of my time in order to test them similarly to what I intended the design to be used for. The bass was much stronger. I ran them full range, and directly compared to my ACI Essence V speakers, which are larger 3 ways, but sealed with an 80hz rolloff. The little Nova's actually had stronger, punchier bass then the ACI's! And held their own fairly well. The ACI's are very smooth, and have a much larger sound to them, with the placement helping that of course. The Nova's have more apparent high frequency energy (I wont say detail), but are still very smooth, nothing jumping out at you. I have to say, I feel like this is a successful design, and anyone who is shoving their speakers up against a wall or cabinet should consider these. The Nova's are going to be perfect for on wall duty as surrounds.


Edited by Jay1 - 1/12/13 at 11:50pm