First build, in progress...

[captainobvious99]

I'm taking the first steps in the process of my first home audio build. Since Ive learned alot from this and other sites, it's only fair that I post my *attempt* for others to see as well, whether succesfull or not. :o
Now I know alot of you veterans would probably recommend something much easier as a beginner project...and you're probably all correct. But I love to fly by the seat of my pants and dive in head first, so this is going to be a big, big challenge for me. I'm quite sure I'll make many mistakes along the way, but its all a learning process and it will be good fun either way.

My goal is to build a reference level WMTMW system with a much different enclosure look. I want something that doesnt look "boxy" or hard edged, and sounds great too. This thread will be my log of build notes and pictures. I'll update it with ideas, progress, failures (hopefully not too many), and look to you all for suggestions, advice and support.

The drivers I plan on using are:

Usher 8955a
Tang Band W4-1320SJ
Vifa XT25TG30

I *may* end up using LCY110 ribbons Im aquiring if I like the sound better as they will still be a decent fit with the overall system. The crossover duties will be handled actively by a Behringer DCX2496. I like the versatility, easy adjustment and tuning, and the option to use it on other builds down the line.

That said, here are my initial *rough* sketches for enclosures.




Because of the shape of the rear portion, I will be doing a mix of fiberglass and wood construction for this project. A rear "shell" and a front baffle would be two pieces, then mated together. I'm no FG expert, but I have used it before and feel comfortable at least with the work. My plan is to build a "mold" to then use to create the shells so that they are visually consistent.

To do this, I went with the recommendation of a friend to use foam to create the base for the mold. I used the polystyrene insulation foam found at the local Home Depot. The reason I used this is its ability to be shaped and smoothed using a standard wood working "cheese-grater" and sand paper. The sheets come in different sizes. I used the 2" thick, 24" X 96" pieces.



Cut to size, 12" X 44"






And then joined together using the 3M High Strength 90 spray adhesive. This is probably not the best stuff available to use, but it made good strong bonds.

[captainobvious99]

Re: First build, in progress...

I used some full paint cans laying around to keep pressure on the pices for a good bond. After that, I measured and marked/traced out the locations where the speakers will eventually be at (mounted to a proper wood baffle of course). This is more just so I could visualize it ;)






Next up, the shaping of the rear shell...This was done using these tools, just a grater a hand saw and rough sandpaper block.

[captainobvious99]

Re: First build, in progress...

After the first round, I was not super happy with the over all shape...needed to be more rounded, especially the sides and transistion to the back. I got some more work done on them yesterday. Here is the current progress after another 2 hours of work :eek: (This takes a while!)



















A couple of things to note...
Earlier I had said that the High Strength 90 might not be best suited for this. As you can see by the craters in some areas, this is where the solution was thickest and reacted with the foam. It slightly eats at the contact point, but still creates a good bond. Also, be sure to wear a breathing mask/respirator while doing any of the work seen in this project, especially later when I get into the fiberglassing. While this foam isnt particularly nasty , its still not going to be fun to breathe it in. The fiberglass is a whole different ball game. You need the proper respirator and filter, and a vented space. Be safe !


Well, there you have it so far. My fiberglass supplies have been ordered and should arrive sometime next week, so until then I am on hold.

Another quick note about my plans for construction...The front baffle will be a thick (appx 1.5-2") hardwood which will be mated to the rear shell once completed. This will allow me to swap out baffles down the road if I decide to try some different drivers/configurations. Also, by doing a pseudo-mold for the rear shell portion, I should be able to reproduce the shells if I ever want to make more. The fiberglass shell should be extremely strong especially considering the curvature. I would expect it to be in the neighborhood of 3/8" thick. One thing Ive been thinking about is resonance of the shell. I dont know if it will be an issue or not, but if I can take steps to ensure that it wont be DURING the construction process instead of bandaiding it later, that would be best. Im open to any suggestions along this regard. Ive considered layering the construction with CLD material ( i have extra laying around collecting dust), and also increasing mass with an additive like sand.

Thoughts ?

EDIT:
Also, forgot to mention, but it should go without saying...the midranges and tweeter will have their own airspace within this enclosure (likely made of MDF-Box inside a box, sort of), so the volume of this shell, after displacement of the mids' box, will be shared by the (2) 8955a's.

[the kid]

Re: First build, in progress...

Wow, with all the effort you are going through and the time it takes to document & post everything, I have a question: In your 2nd post, what are the speakers ALREADY built in the background?

And your current project is a doozy!

[captainobvious99]

Re: First build, in progress...

Wow, with all the effort you are going through and the time it takes to document & post everything, I have a question: In your 2nd post, what are the speakers ALREADY built in the background?

And your current project is a doozy!

Those would be my LG laundry transducers ;)

No speakers currently built, unless you consider my PVC test enclosures sitting in the living room anything special. But I didnt see them in any of the pics.

[DoubleTap]

Re: First build, in progress...

How much air volume are you going to have once that's done? Sure doesn't look like enough for a pair of 8955's, and a separate internal chamber for the 2 Tang Band's.

Your process sure is interesting though. I'll be interested in how it turns out.

[jettore]

Re: First build, in progress...

I have always wondered about doing a fiberglass enclosure. Keep us posted, this is very interesting. Looks good so far. How are you figuring enclosure volume? Are you going to have a separate interior space for the mids built off the back of the baffle?

Edit: Looks like DoupleTap beat me. I sure do type slow.

[captainobvious99]

Re: First build, in progress...

How much air volume are you going to have once that's done? Sure doesn't look like enough for a pair of 8955's, and a separate internal chamber for the 2 Tang Band's.

Your process sure is interesting though. I'll be interested in how it turns out.

Volume is going to come in shorter than I had hoped actually, you are correct. I would guestimate it could come in at around 60 liters give or take. Im considering a few things now. I had not really given a whole lot of thought to just how I would do the stand for these. I'm thinking that to increase volume, I can use the stand as additional enclosure volume. It would be tricky, but I think its doable. I dont particularly like the stand look in the sketch anyway, so I had already planned to deviate from that.
Its either that, or I end up tuning higher or going sealed and then using a sub for low end support.

[the kid]

Re: First build, in progress...

Those would be my LG laundry transducers ;)

No speakers currently built, unless you consider my PVC test enclosures sitting in the living room anything special. But I didnt see them in any of the pics.

oh, right. noowww i get it...(see signature below)

[dcibel]

Re: First build, in progress...

Wow, I like this idea, all I can say is "why didn't I think of this?".

Looks like a very cost effective and simple method to create odd-ball cabinet shapes. All I have to do now is learn to apply fibreglass well. The only downside of this method I can see is that any imperfection may stick out like a sore thumb, lumps and whatnot. I look forward to seeing how this turns out, I may try it in the future since I have a lack of tools and workshop and skill for the woodwork.

[captainobvious99]

Re: First build, in progress...

Wow, I like this idea, all I can say is "why didn't I think of this?".

Looks like a very cost effective and simple method to create odd-ball cabinet shapes. All I have to do now is learn to apply fibreglass well. The only downside of this method I can see is that any imperfection may stick out like a sore thumb, lumps and whatnot. I look forward to seeing how this turns out, I may try it in the future since I have a lack of tools and workshop and skill for the woodwork.

Thanks.

Here's how I plan to avoid the craters...
Since the foam would be completely eaten by applying fiberglass resin anyway, I will mask the entire thing with blue painters tape. After that, I will stretch over the structure an elastic cloth material (thicker than grill cloth) and apply resin to it. Once two coats is applied and cured, I'll remove the very thin shell and begin adding the fiberglass structural layers (chopped mat, resin and glass fibers) to the INSIDE of the shell piece, slowly building it up. This should leave very little to do as far as shaping and smoothing the exterior goes. Some sanding and spot putty here and there and I should be good to go. :D

[evilskillit]

Re: First build, in progress...

Not to belittle the awesome build that captainobvious99 is undertaking, but car audio guys have been doing this for a long time. I was never quite sure why we didn't do it here, other than that it takes some artistic talent, and fiberglass smells bad. If I thought I had the time and talent to pull of making cool fiberglass boxes I'd be doing that instead of mucking about with mdf and plywood. ;)

That and you have to paint em, you can't exactly veneer that thing. A lot of us hate painting too.

Check this out, a video showing how this is going to work.

Wow, I like this idea, all I can say is "why didn't I think of this?".

Looks like a very cost effective and simple method to create odd-ball cabinet shapes. All I have to do now is learn to apply fibreglass well. The only downside of this method I can see is that any imperfection may stick out like a sore thumb, lumps and whatnot. I look forward to seeing how this turns out, I may try it in the future since I have a lack of tools and workshop and skill for the woodwork.

[dcibel]

Re: First build, in progress...

Thanks.

Here's how I plan to avoid the craters...
Since the foam would be completely eaten by applying fiberglass resin anyway, I will mask the entire thing with blue painters tape. After that, I will stretch over the structure an elastic cloth material (thicker than grill cloth) and apply resin to it. Once two coats is applied and cured, I'll remove the very thin shell and begin adding the fiberglass structural layers (chopped mat, resin and glass fibers) to the INSIDE of the shell piece, slowly building it up. This should leave very little to do as far as shaping and smoothing the exterior goes. Some sanding and spot putty here and there and I should be good to go. :D

I was thinking that some plaster, dry-dex, or bondo would do the trick for filling craters and making a smooth surface. Something that can be sanded easily.

I have a friend who is a an artist, he has this old antique radio that he wants me to turn into an iPod jukebox. I may have to confer with him for some artistic talent if I go this route with a future speaker build.

[captainobvious99]

Re: First build, in progress...

Not to belittle the awesome build that captainobvious99 is undertaking, but car audio guys have been doing this for a long time. I was never quite sure why we didn't do it here, other than that it takes some artistic talent, and fiberglass smells bad.

Thats actually how I got my experience with fiberglassing

I wanted to get more upfront bass and impact to get better sound in the vehicle and the stocl locations accomodated a 5.25" driver. After upgrading to 6.5 and still not being happy, I made the jump to 8" midbasses which required a ton of work. :eek:

I went from the top picture (front doors, stock), to a first failed effort, to the current state...


















They still need a little more finishing work, but you get the idea...





.

[mgrabow]

Re: First build, in progress...

sweet. Looks good...