Autotuba/Floorstanding speaker worklog with pics.

[mastertee31]

So I decided to take on a new project building a pair of home audio speakers. I thought you guys might like to see the work log.

They're intended solely for high efficiency and music reproduction. These are the second pair of speakers I've built for home use (The first being a pair of bookshelfs) I found the bookshelfs to be quite good but they lacked in the low end. These are a mix of my bookshelfs re-built bigger and better, along with folded horn woofers to address my bass problems. These speakers will feature the Focal polyglass 165 V1's I already had lying around. The Focal's are decent speakers for now, and If I decide to upgrade I can always swap out the speakers with minimal work. The folded horn woofers are MCM brand (known for they're incredible efficiency in this application)

Estheticly I'm aiming for a look similar to the wilson watt puppies and these:




These are progress pics from the last 3 weeks (On and off work):

















Almost done....:



I will post more as I go along.

[DJPhatman]

May I ask...Why the MDF? Even for a permanent install, the MDF is so much heavier than 1/2" plywood. And such a PITA to work with.

Also, is the glue you are using expanding polyurethane glue? Horns require an airtight seal through the entire pathway to function properly. Air leaks pretty much anywhere in the horn's pathway will ruin the sound.

[LelandCrooks]

Very nice.

I can answer the glue. For home speakers you are going to finish, the pl is problematic. It's difficult to cover if you want a high gloss finish unless you veneer. Careful attention to detail and you can build with yellow glue, but it is not nearly as strong, nor does it fill . I'd never use it for a box I was going to move around, period. For high end furniture grade construction I would.

[Sydney]

Practically speaking doesn't working with any engineered wood product involve dealing with the pluses and minuses of each product.
Not all products are the same; MDF, Ply, etc are being made out of differing composition of fiber types ( including hemp ) and differing glues ( instead the formaldehyde based glues ), and differing densities - now HDF is available.
There continues to be different materials on the market: Hardwood veneered Plywoods and an increasing variety of laminated products like MDF core boards with hardwood and various plastic laminates. There are also panel products that are laminates of materials of differing acoustic materials designed with intent of having a strong but acoustical absorbent material.
If a panel material came out that was a strong as ply, and lighter there would a lot of interest in it and a serious evaluation of the pluses and minuses of getting it to work.
I'm not a master furniture finisher, so I have not been able to get any raw wood product to look good, without some kind of exterior coating/treatment/hardwood veneer or laminate.

[WB]

Air leaks pretty much anywhere in the horn's pathway will ruin the sound.

I'd be very concerned about air leaks using the yellow glue. I would at a minimum use the polyurethane on all the internal panels.

[Tim A]

For high end furniture grade construction I would.

As would I, however, on that box I would absolutely positively seal every single joint with a bead of hot melt glue.

When looking a the pics, I have to wonder. Is this a another case of a guy who's built a few cabinets 'knowing a better way', or is it a case of a guy with enough experience to know how to make changes to the plans and properly compensate for those changes?

[Mikey]

When looking a the pics, I have to wonder. Is this a another case of a guy who's built a few cabinets 'knowing a better way', or is it a case of a guy with enough experience to know how to make changes to the plans and properly compensate for those changes?

Looks like he has the tools and ability to do woodworking, and it looks like he pays attention to detail, but the bottom line is whether he did SOMETHING to absolutely ensure that every joint is airtight. It's a shame he didn't use the specified wood and adhesive, as the build would have been easier and the end result would have been better, but if it all works out well in the end, then at least he has this experience under his belt.

[mastertee31]

May I ask...Why the MDF? Even for a permanent install, the MDF is so much heavier than 1/2" plywood. And such a PITA to work with.

Also, is the glue you are using expanding polyurethane glue? Horns require an airtight seal through the entire pathway to function properly. Air leaks pretty much anywhere in the horn's pathway will ruin the sound.

Finding void free plywood is somewhat problematic where I live. The weight of the MDF is not a problem for me and is something I actually want. Weight will help reduce unwanted resonances and improve sound quality. My bookshelf's that I made were of MDF and were very easy to finish, primer, basecoat, clearcoat and they turned out quite good.

Unfortunately I didn't use polyurethane glue, even though I did buy some for this project. (I had concerns of how it would cover once painted) I did however put very generous amounts of wood glue down, Brad nailed down and ran 2 seperate beads of glue down all joints to insure a good seal. I also put a bead of silicone down all the joints. (Overkill I know)

The only part you guys are making me nervous about now, is when I put the finished side on. I probably should have used the poly glue for that part, oh well "live and let learn..."

[mastertee31]

When looking a the pics, I have to wonder. Is this a another case of a guy who's built a few cabinets 'knowing a better way', or is it a case of a guy with enough experience to know how to make changes to the plans and properly compensate for those changes?

Looks like he has the tools and ability to do woodworking, and it looks like he pays attention to detail, but the bottom line is whether he did SOMETHING to absolutely ensure that every joint is airtight. It's a shame he didn't use the specified wood and adhesive, as the build would have been easier and the end result would have been better, but if it all works out well in the end, then at least he has this experience under his belt.

I appreciate the compliments and criticisms. I do however regret not using the poly glue, but don't quite understand how the choice of wood would make for an easier build?

[mastertee31]

These are some pics of previous projects I've done: (I've learned something new from every single one)

The only picture I have of my bookshelfs unfortunately: (The orange peel you see is from applying the primer with a roller, this time everything will be done with a HVLP gun)


The center console I built out of fiberglass for my car: (I never ended up using it lol)












Rear speaker pods for my civic:






Front door pods in my civic:






Current setup: (1 12" sub with 2 8" sub/midbass in a stealth install)

[Tim A]

Unfortunately I didn't use polyurethane glue, even though I did buy some for this project. (I had concerns of how it would cover once painted)

So, you decided to possibly sacrifice performance for aesthetics? Bad move. Also, polyurethane glues such as Gorrilla Glue are not the same as PL.

I did however put very generous amounts of wood glue down, and ran 2 seperate beads of glue down all joints to insure a good seal.

Wood glue is not flexible. Once it dries, it is brittle. There is very high pressure in the throat horn which could cause wood glue to pull apart over time.

I also put a bead of silicone down all the joints. (Overkill I know)

Not in this case, it may be the only thing that saves the cab's performance. However, keep the box ventilated while curing, and make very sure it is fully cured before installing the driver.

There's really only one way for a neophyte to build one of Bill's cabs. Follow the plans. Anything else and you have no idea what the end result will be. Then we and everyone else on the internet hears about how crappy Bill's cabs are because they don't perform as advertised. They will perform exactly as advertised, but you have to build them as shown in the plans. Please keep that in mind when you fire it up.

[DJPhatman]

mastertee31, I will assume that you live in a fairly populated area. Are there kitchen cabinet makers in your area? I'll bet there is. Stop in one day and ask them where they get the high grade plywood that they use. You might even be able to work out buying from them, saving you run around time and money. Plywood is used for a couple of reasons. It's cheap, it's very strong when used as directed, it's much lighter in weight, it's easier to work with, it doesn't soak up moisture like a sponge...the list goes on.

If you will post where you live, I am sure someone on the forum will guide you to a source for good plywood.

BTW, if you are in the US, seriously consider building a set of SLAs. With your skills, I think you could knock a pair out in a day, sans finish. They are inexpensive to build, sound fantastic, and are a pretty easy build. I am finishing my first one, that I have built one-handed!

[Mikey]

With your obvious degree of interest in speaker building, it would definately do you a lot of good to read through all of the posts on this forum and join-in on "the festivities". Please don't take this wrong, but your pics show that you've obviously been influenced by much of the misinformation which is abundant in the world of speaker design (ESPECIALLY car audio), and this is the perfect place to deprogram and learn things properly. Almost all of us came here with our heads full of such misinformation, so you're far from alone, and the good news is that it's definately curable. There are a lot of very sharp, knowledgeable experts here, and they share their help and knowledge freely. "Nothing great was ever achieved without enthusiasm", and you have that in spades, so you're already well on your way.

[Ron K]

Pretty nice glass work ! Do you ever do vacuum forming? How bout exponential or CD horns?

[mastertee31]

Pretty nice glass work ! Do you ever do vacuum forming? How bout exponential or CD horns?

Vacuum forming, nope, but I'd like to try one day. As for horns this is all new to me so I have a lot to learn.