Overnight Sensation Build -- Two Sets

[Randall Kepley]

Re: Overnight Sensation Build -- Two Sets

Ron, man those are looking GREAT! I love threads like this, and I would also love to hear a set of OS. Keep the great pix coming. And Jim85iroc, by looking at your black finish, I can tell thats not your first square dance in wet sanding and buffing, Looks great also. R.K.

[Soundslike]

Re: Overnight Sensation Build -- Two Sets

From jim85iroc:

... I've been happy with the Duplicolor stuff. When you seal the MDF, it doesn't take a lot of high build primer to get a smooth paintable surface. I've even built enclosures without using a sealer... just using extra coats of the high build primer to seal the wood. That's how the tall cabinet in the attached pic was done, prior to the automotive Urethane finish. After a wetsand & buff, the black paint was mirror smooth, just like you'd expect from a high quality automotive urethane finish. That said, a coat or two of sanding sealer or equivalent will result in a much faster & easier primer application.

Good suggestions -- I've also had good luck with Duplicolor products or similar materials from other manufacturers. I'll just about always grab a spray can if the project is small enough, rather than go through the setup, cleanup, and overspray tasks. I haven't tried wet sanding enclosures yet, out of concern that moisture might find its way into the MDF. You must have done a very thorough masking job to keep from splashing/dripping/seeping water into the enclosure. You sure got an impressive result -- your suggestions have motivated me to give it a try. Care to contribute a little more detail about your process, such as masking, the grits used, buffing compounds, buffer type, pad types, drying times? I own a Milwaukee buffer that I'd like to use on the larger surfaces.

About sealing -- I've recommended sealing with resin in this thread because it penetrates and strengthens the MDf and provides a good surface for the body filler to adhere to. I suspect that the body filler would adhere to the MDF nicely on the flat surfaces without the resin, but the exposed edges might be problematic. I also wanted to avoid the possibility of a splotchy look, caused by uneven absorption of the finish material, but a primer should should take care of that. I have had primers fail me, however.

Just a note here to anyone who might be following the resin sealing process I've been describing -- a bit of recent reading has shed a little light on the "waxed vs. unwaxed" issue. After visiting a site recommended by Beemain (now Mikers) I discovered that the waxed types are formulated to minimize clogging of sandpaper. The unwaxed types, are strongly recommended for multiple layups, which I take to mean the process of building up multiple layers of fiberglass cloth and resin. Most likely, wax could interfere with adhesion of layers.

And more valuable input from Randall Kepley:

...I will be more than happy to address your questions and I also want to say that , Please dont think Ive tried to Hijack your thread. Its quite obvious you have put alot of time and effort into this thread and I dont want to detract from what this is realy about and thats "Your great pair of OSB builds" and they do look great by the way. I also want to say the advice I give may not be the only route to take in any given certain situation but I can promise you what ever advice I give, is advice that is tried and true and I use w/ great success every day. To me this is how I make my living and not just a hobby. Theres alot of crappy advice on diff forums and Im not in the habit of steering anyone in the wrong direction...

Randall, please have no concern about the appearance of hijacking -- I'm honestly motivated by a desire to create a string that will be useful to others, and I can see you want to do that too. If someone, like yourself, is gracious enough to offer an authoritative opinion, that's great. Your contributions have taught me a lot, and I can't help but think that others are learning too -- things that they would otherwise have to figure out through trial and error. By all means, please continue to contribute -- you've improved the quality of information here a lot. And please, be as thorough as you think necessary.

I'll be looking for a source for the Titebond adhesive -- I really don't like using the contact adhesive, unless I have to. I'm also interested in the vacuum bagging process -- maybe I can justify the investment. It's getting harder and harder for me to credibly use the "It's an investment dear; it really doesn't cost that much when you amortize the cost over a lifetime." argument, because of my, uh, advanced age.

Thanks again Randall. By the way, I think you'd love the Overnight Sensations.

[jim85iroc]

Re: Overnight Sensation Build -- Two Sets

From jim85iroc:


Good suggestions -- I've also had good luck with Duplicolor products or similar materials from other manufacturers. I'll just about always grab a spray can if the project is small enough, rather than go through the setup, cleanup, and overspray tasks. I haven't tried wet sanding enclosures yet, out of concern that moisture might find its way into the MDF. You must have done a very thorough masking job to keep from splashing/dripping/seeping water into the enclosure. You sure got an impressive result -- your suggestions have motivated me to give it a try. Care to contribute a little more detail about your process, such as masking, the grits used, buffing compounds, buffer type, pad types, drying times? I own a Milwaukee buffer that I'd like to use on the larger surfaces.

My process is fairly simple. I soak the sandpaper in a coffee can of water, and re-dip as needed. I wasn't the least bit concerned about small amounts of water working their way into the enclosure. I had enough overspray on the driver mounting surface to protect it from absorbing water, and if a few drops got into the cabinet, it wasn't going to be enough to cause any problems.

Essentially, when I sprayed the clearcoat over the black basecoat, I put it on with the intent of wetsanding & buffing... that means at least 3 wet heavy coats. When in doubt, err on the side of too much clear. If it runs, you can wetsand it out, and with experience you learn how to get it as heavy as you can without runs. Once it dries, then it's a matter of cut & buff. I usually block sand with 1000 to 1200 grit to knock down the orange peel. Once that's down, I move to 20 micron paper until the 1200 scratches are gone, then repeat with 10 micron paper. From that point, it's on to a mild rubbing compound, followed by a swirl remover, then your car wax of choice. With something as small as one of these little speakers, or any front baffle for that matter (way too many edges), you're usually better off doing the rubbing compound & swirl remover by hand instead of with a buffer. Taking a buffer to something with so many edges is just asking for trouble. By the time you sand something with 10 micron paper, it's already so smooth that there's really not a lot of elbow grease left with the compounds, so it makes sense to do it by hand when dealing with something so small. That said, I probably hit the sides, top & bottom of that cabinet with the buffer because I'm impatient, but when I did the front baffle of my Silver Flute - Vifas (Zaph design), I polished those completely by hand. Attached are a couple lousy pictures. As dusty as they are, you can get a decent sense of the reflection in the base of the stands, which were finished in the same way.

For those who don't have access to automotive paints, don't be afraid to use spray paint then wetsand & buff that. You can get nearly identical results with spray cans.

With any luck I should get to painting the baffles of the RBRs that I'm currently building in the near future. When I do, I'll document the process and post it here.

[Soundslike]

Re: Overnight Sensation Build -- Two Sets

Very nice work jimiroc85. I'll be using your process in the future. I think I'll be refinishing a Tritrix TL set I have. Thanks for the tips..

[ericJ]

Re: Overnight Sensation Build -- Two Sets

More good ideas -- thanks Leroy and Swander.

Continuing with the build process -- after completing the veneering of one set, I flush trimmed the baffles with a router and a flush-trim bit. A flush trim bit does a great job of matching up the baffle with the box and I ended up with the baffle perfectly matching the surface height of the veneer. As I mentioned in a reply to Randall above, I did experience a little superficial marring of the veneer surface -- I say superficial because it was easily removed with light sanding, but it did cause me think I'd be wise to guard against that in the future. Leroy and Swander suggested using tape and that does seem likely to either prevent a problem, or at least raise my comfort level. I also rounded over the edges (top, bottom and sides) with a 1/2" round over bit and router, and flared the ports on both sets with the same bit. The vents were originally epoxied in place flush with the outer face of the baffle on one set, and the back on the other set. That meant that routing around the port opening would involve cutting the PVC which left about 1/4" of contact area between the PVC and the MDF where they are mounted. The PVC cuts easily, providing you don't rush and move the router in the correct direction.

After looking at your photos and reading your description, I think I may have messed up on my build. I did the reverse. I assembled, flush trimmed, rounded over the baffle, sealed and painted. NOW, I have to veneer the sides, bottom and back. This means the veneer will be a hair higher than the baffle all around.

[Soundslike]

Re: Overnight Sensation Build -- Two Sets

Continuing with the build:

I block sanded the primer with 220 grit paper, then 400 grit paper. I used spot putty to fill in a few nicks and scratches visible on the surface. I'm wearing gloves here in an attempt to prevent all the moisture in my fingers from being soaked up by dust generated by the sanded primer. The black primer makes your hands look like you've been handling charcoal all day Gloves also help to avoid depositing oils on the primed surface. The rounded edges were sanded using the finest flexible foam block sander I could find.



After sanding, I painted the front-vented enclosures with an automotive urethane three-part paint, applying a tack coat followed a few minutes later by a full wet coat. Here's a photo of the product I used:



I'd judge the finished result as fairly successful, but not perfect. These photos were taken as soon as the paint dried enough to allow the enclosures to be moved inside. The paint continued to level out over the next 24 hours, producing a smooth glossy finish that will be impressive to most.

Here again, I didn't use my best equipment and opted instead for the detail gun. In hindsight, I'd say if a project is worth painting with materials of this quality, use your best gun. When mixed according to the specified ratios, this paint is fairly thick and small siphon guns don't do it justice.

One other thing to consider -- to get the outstanding performance three-part urethanes are capable of, you have to use a hardener that's suitable for the temperature range you'll be painting in.

At this point, if perfection is your goal, and you're willing to devote the necessary time and effort, follow the process described in jimiroc85's most recent post (most recent relative to this post). This process is generally called "color sanding" and has been used for many years -- it was very prevalent for quality automotive paint jobs using lacquer (for those who could afford it). I plan to use this process the next time I do a piano black finish (the process described by jimiroc85).





The veneered set was finished in semi-gloss black and urethane varnish, both applied with spray can products. Here we we the four enclosures after finishing. That nick you see above the tweeter cut-out on the nearest enclosure was caused by a careless bump of the spray gun.

[Soundslike]

Re: Overnight Sensation Build -- Two Sets

I assembled, flush trimmed, rounded over the baffle, sealed and painted. NOW, I have to veneer the sides, bottom and back. This means the veneer will be a hair higher than the baffle all around.

Eric,

It's probably not too late, if you want to go to the trouble. The baffle width and height could be increased by adding strips around the perimeter. If I were tackling a problem like that I'd cut a dado 3/4" in width (from the front edge of the baffle and into the edge of the box). That should be easy to do on a table saw. I guess the easiest way to describe what I'm talking about is with a drawing. The dado would go around the perimeter, no more than 1/4" deep (1/2 the thickness of the box sides), and 3/4" deep (measured front to back) as shown in the drawing. The yellow indicates the baffle, and the red indicates the box sides and top. Then I'd cut strips from MDF just slightly larger than the dado and glue them in place. You could then apply the veneer, followed by flush trimming of the enlarged baffle. Body filler will do a great job of repairing any visible seams.

That's probably not as much trouble as it sounds, but you could also just live with the higher veneer. I think it would be pretty tricky, but you might get away with sanding a taper into the baffle and the veneer. Let us know how it turns out...

I feel your pain :(

[Mikers]

Re: Overnight Sensation Build -- Two Sets

for filling with your glazing putty may I suggest a razor blade? I works really well considering you should only be filling pin holes and small pocks or possibly deep scratch here or there from sand paper.

[Soundslike]

Re: Overnight Sensation Build -- Two Sets

for filling with your glazing putty may I suggest a razor blade? I works really well considering you should only be filling pin holes and small pocks or possibly deep scratch here or there from sand paper.

I noticed that you did that in your build -- I'll give it a try.


Now that the enclosures were completed, I turned my attention to the crossover networks. Actually, I began planning the crossover network layout when drawing the plans for the enclosures posted at the beginning of this string. Using a CAD program, my first step was to measure and draw the individual components to scale in top view. I also drew the inductors in side view since one type would be mounted vertically. The components are shown in the area labeled "Component Set," in the drawing. Drawing the crossover network to scale makes it possible to determine how everything will best fit on a small board, and ensures that the completed board can be installed inside the enclosure through the driver openings. Once the components were drawn, I copied the individual components and placed them in a group which was manipulated experimentally by rotating and moving them around. I established three requirements for whatever design I ended up with:

1. The board should be as small as reasonable and fit easily through the driver opening.
2. The two inductors should be placed apart as far as possible from each other, with one mounted horizontally and the other mounted vertically.
3. The input and output screw terminals should be located on different sides of the board to make connections shorter and more logical.
4. The two heat producing components (the resistors) should be separated, i.e., not located beside each other.

Here's a good PE help article on the subject of crossovers -- the orientation of inductors relative to each other is discussed within the article.

Eventually, after moving things around a bit I arrived at three different possibilities, all using compact boards. I ended up selecting the one in the upper right corner, shown within a box which represents the available real estate on the "floor," inside the enclosure. The connections, which will be made up under the board, are shown in red and blue.








In this next drawing, I used the CAD program's auto-dimensioning feature to show where holes would be drilled through the board for wires to pass through, and for screw mounting of the terminals. I should have changed the settings so as to avoid dimensions down to 1/32" which only serves to unnecessarily complicate the drawings. I cut the boards to 3 3/4" X 2 3/4", dispensing with the teeny tiny fractions.
Note: I strongly recommend that you use the last drawing in this post, if you intend to use my layout and dimensions on your board. I've cleaned up things a bit, by lining up the holes vertically and horizontally, as much as possible. That makes marking the hole locations much simpler, since many are located along the same line. Look at the drawing (which also shows how the board is wired to the other components in the speaker) and it should be clear.



Finally, I used the mirror copy feature to create a drawing showing the wiring as it would actually look on the underside of the board where the connections would be made. I know this is obvious to most, but the dots indicate connections (excluding those showing the location of the screw holes for the terminals), and the little humps indicate that the circuit passes over the wire beneath (most importantly, it does not connect to the wire it passes over). This mirrored view provides a road-map for the connections on the underside of the board.

I should note at this point that the same result can be achieved (planning the layout) by simply drawing the components to scale, full-size, and making paper cut-out to represent the components. Heck, it could even be simpler, but I have this drawing program see, and I just have to use it. Actually, I'll have to admit that I do enjoy drawing things with the two programs I use...



This next photo shows the underside of a template I made for marking hole locations on the four boards I would be making for this build. Note that I marked the circuit on the template -- that makes it easier to check your work as you go along.


1/4" Masonite (tempered hard board) was used for the circuit board. A 4 X 8 sheet of this stuff seems to last forever, even though I find uses for it almost daily. The panel this piece was cut from got wet, but it's still usable for many things (I'm trying to offer an excuse, no matter how lame it is, for the somewhat softened look of the hardboard).

I used European style terminals this time around and I'm very happy with them. They're small, and economical since you can purchase longer strips and cut out what you need. Three connection terminals are not easy to find.

I used hot-melt glue to secure the components on the top-side. I did use a zip-tie for the vertically mounted air-core inductor because it's likely to be subjected to stress. I don't find zip-ties necessary for the other components; the hot-melt glue holds well, and the leads (passed through the board) really provide enough strength on their own. That, combined with the added strength afforded by the hot-melt glue, makes for a very sturdy board.



Here's a view from an angle:


Components should be mounted with their identifying labels up. In the event there's any question about what the component's value is, or should be, the repair technician (that might be you) can easily read the value.

Here's a view of the underside of the board showing the soldered connections. The last time I did this (showed the underside) I got a few critical comments about my soldering. I took them to heart, but I doubt I'll get an A for the work I did on these. Onward and upward, as they say, I guess....



Although not shown here, I used short pieces of dowel to make stand offs for the board. These ensure that the circuitry is held out of contact with the floor of the enclosure.

The boards were installed using hot glue on the ends of the dowel standoffs. Working as I was through the driver opening, it was necessary to make up the wiring that would connect the input side to the binding posts, and the output side to the drivers, before installing the boards. Once the necessary lengths are determined, you can attach the wires to the board terminals, before installing the board inside the enclosure.

Edit: I'm adding this edit, mentioning something that perhaps I should have mentioned when I first wrote this post, about nine months ago. I'm referring to the polarity of the tweeters. The OS design uses reverse polarity on the tweeter connections, i.e., the positive wire for the tweeters from the crossover board is connected to the negative terminal on the tweeter. The positive side of the tweeter is connected to the common ground. Paul's crossover drawing specifies reverse polarity, but the little minus sign is easy to miss. I must confess that I missed that little detail until someone asked about it in a PM. The harm done to audio quality by not using reverse polarity is minimal, at least to the untrained ear. Paul tells me there's a deep reverse null that results -- narrow, but deep.

Here's a drawing showing connections to the binding posts and drivers. The dimensioning has also been improved to make layout simpler.

[cwad8505]

Re: Overnight Sensation Build -- Two Sets

Man oh man.. I love your builds, but I must say, you and I go at XO's completely different!! lol... Mine usually go a lil something like this.. grab a sheet of paper out of the printer tray.. lay it out to get the same connections close to each other, then power up the soldering iron... and rock and roll.. and, my 2nd XO almost always looks a lil different than the first one..(lessons learned on the first).. Attached is a pic of my XO's for my Nano NTN's.. you'll see that the 1 on the right was my first one, then learned a way to rid of some jumpers... Well, I guess the end result is the same.. only yours is a showcase on the inside as well as the out..thanks again for sharing..BTW.. did I mention that I'm completely jealous of your set-up (Home, Hangar, tool shop, AIRPLANES?!!, and last but not least, weather!)???
Happy Building,
Chris

[Soundslike]

Re: Overnight Sensation Build -- Two Sets

Man oh man.. I love your builds, but I must say, you and I go at XO's completely different!! lol... Mine usually go a lil something like this.. grab a sheet of paper out of the printer tray.. lay it out to get the same connections close to each other, then power up the soldering iron... and rock and roll.. and, my 2nd XO almost always looks a lil different than the first one..(lessons learned on the first).. Attached is a pic of my XO's for my Nano NTN's.. you'll see that the 1 on the right was my first one, then learned a way to rid of some jumpers... Well, I guess the end result is the same.. only yours is a showcase on the inside as well as the out..thanks again for sharing..BTW.. did I mention that I'm completely jealous of your set-up (Home, Hangar, tool shop, AIRPLANES?!!, and last but not least, weather!)???
Happy Building,
Chris

I'd be the last one to say you're doing it wrong. Your crossover works every bit as well as mine, and you're finished a lot sooner. You'll be listening to them while I'm still printing out my diagram. The only good reason to go to a lot of trouble making things neat is if you get a lot of satisfaction out of the process. I do, but I'll readily admit that there are more efficient ways of doing things. Yours look good to me by the way...

I am very fortunate to live where I do, and to be around aviation all the time. I love it here, but the weather is a trade off. From mid May through about the first of October, its very hot. Very much like the heat you feel when you open your oven -- hot and dry. I will say that I've never been hotter than I have in places like Oshkosh, Wisconsin where it can be both humid and hot. I remember a day there that got in the vicinity of 105 degrees, and it was very humid. It was worse than 118 or so here. Thankfully, those temps aren't seen too often in either place.

[cwad8505]

Re: Overnight Sensation Build -- Two Sets

I very much understand the heat of which you refer to.. I was stationed at MCAS Yuma for 3 years...Ridiculously hot! Thanks again! Chris

[Leroy R]

Re: Overnight Sensation Build -- Two Sets

Looks like you used the same hardboard I used for my crossovers. I like how you drilled little holes and routed all of your wiring to the underside of the board, makes it look much neater. I do have a question though.

I see you have a tye wrap to help secure the small inductor, but I don't see one on the large inductor. Are you just relying on the hot glue to hold it in place? I initially just used hot glue and mounted mine to the side panel behind one of the woofers. When I took them back out, both inductors had come loose from the board and one had actually pulled most of the other components loose as well. While I had them out during the finishing process of the cabinets, I added 2 tye wraps to the large inductor, 1 to the small inductor and 1 for the large capacitor. I didn't want them falling apart on me again. I didn't notice any components loose in the MTs where the panels are glued to the bottom of the cabinets, just the MTMTLs where they are attached to the side of the cabinet, where gravity was working against me. The center didn't have any loose components since it also is mounted to the base of the cabinet, but since it was screwed in with feet like the MTMTLs, I took it out and added the tye wraps to it too. I got lazy on the MTs and just hot glued the crossovers directly to the base of the cabinet without feet, so they would be a little harder to get back out.

[Soundslike]

Re: Overnight Sensation Build -- Two Sets

I see you have a tye wrap to help secure the small inductor, but I don't see one on the large inductor. Are you just relying on the hot glue to hold it in place? I initially just used hot glue and mounted mine to the side panel behind one of the woofers. When I took them back out, both inductors had come loose from the board and one had actually pulled most of the other components loose as well. While I had them out during the finishing process of the cabinets, I added 2 tye wraps to the large inductor, 1 to the small inductor and 1 for the large capacitor. I didn't want them falling apart on me again. I didn't notice any components loose in the MTs where the panels are glued to the bottom of the cabinets, just the MTMTLs where they are attached to the side of the cabinet, where gravity was working against me. The center didn't have any loose components since it also is mounted to the base of the cabinet, but since it was screwed in with feet like the MTMTLs, I took it out and added the tye wraps to it too. I got lazy on the MTs and just hot glued the crossovers directly to the base of the cabinet without feet, so they would be a little harder to get back out.

Lee,
I don't use more zip-ties or tye wraps (I believe they're both the same thing) because I don't think they're necessary, providing that gravity is working for you, and not against you, and providing that an ample amount of glue is used. I haven't experienced any problems yet, but then I haven't taken apart any of the 16 speakers I've built that way. All except one of them, have the crossover boards mounted to the bottom of the enclosures where gravity will pull them down. More importantly, gravity is not constantly pulling in a direction that would promote separation of the components from the board. The only component I've had any concern about, up to this point at least, is the vertically mounted inductor standing on its edge. That's the one component I've recommended securing with a zip-tie. Running the component leads through the board adds a lot of strength also -- in fact, as I stated above, I don't think even glue would be necessary on anything but the inductors, when the components are mounted that way.

My preference for not using a lot of ties, I will admit, is to some extent based on the appearance of the finished board. As I mentioned in my reply to Chris (cwad8505) I derive a bit of personal satisfaction when things I make turn out looking nice. Conversely, I don't like to make things that turn out looking, uh, less than craftsmanlike. As I also said to Chris, I'll readily admit that appearance logically should be well down the list of priorities for something that's probably never going to see the light of day again, once it's installed inside the enclosure. So, to anyone bothering to read this rather long discussion about securing crossover components, I'd recommend securing with zip-ties if you value the secure feeling of knowing there's no way in heck they can ever come loose, over the satisfaction of making something that few will probably ever see.

Based on your experience, I think I'll go out today and inspect the one Tritrix MTM I'm using vertically, in the shop. The crossover board in that one has been setting vertically for more than 6 months. I'll let you know what I find. I may end up eating my words:o

UPDATE: I removed the tweeter from my vertically standing Tritrix MTM and inspected the crossover network. I'm happy to report that the crossover is still hanging in there (shameless pun). Nothing seems to have moved, despite being in the vertical position for quite a while. I'd hazard a guess that eventually gravity will win the struggle, but this speaker was intended for use as a center channel in the horizontal position, so it will probably spend most of its life laying down, probably with the two MTMTLs I have. The fact that everything is still in place makes me even more confident that horizontally mounted crossovers will do just fine using the fastening techniques I've described above. But, there's no good reason I can think of for not using the zip ties, other than taking up a bit more room -- particularly if the wiring connections will be on the top surface of the board.

Thanks Lee for your contribution...

[jim85iroc]

Re: Overnight Sensation Build -- Two Sets

After looking at your photos and reading your description, I think I may have messed up on my build. I did the reverse. I assembled, flush trimmed, rounded over the baffle, sealed and painted. NOW, I have to veneer the sides, bottom and back. This means the veneer will be a hair higher than the baffle all around.

I trim my front baffle before I do my veneer work under the assumption that by the time I seal, add a few coats of high build primer, a couple coats of black, and 3+ coats of clear, that my paint thickness will be about equal to my veneer thickness and result in a good overall match. So far in the builds I've done, this has worked out well.