[musiclear]

Here is a version of the "Avalon Acoustics Time" with my own tweaks added. I decided to go bigger than the OEM version and give it a bit of a Tee Pee shape. The approximate measurements are about 52" tall, swept back 6°, 14.25" wide at the bottom and 10" wide at the top and about 22.5" deep.  1.25" side and back panels, 1.5" top and bottom and 3" a front panel.

 I wanted to open up the space behind the woofers so I choose to use cut out panels for my fist two layers of the four front baffle layers. This three inch front baffle depth gave me the depth I needed to cut the side angles, and the cut outs in the first two layers lowered the weight of the baffle and I believe still maintains good panel stiffness. Here are some of the drawings I went with.

       

 



Keep in mind that some of these measurements have changed by a fraction here and there, so please do not use this as a plan without checking all the measurements for yourself."
The Drivers are Wavecor WF182BD02 woofer, TW022WA05 Tweeter, a pair of Dayton RSS265HF-4 and two Dayton 12" PR's. 

Here is a box model of tuning and frequency response.

[musiclear]

I've had an opportunity to start cutting wood and this is what the beginning looks like held together with big clamps. 





I'll be including braces that look like these pics.  The drawings suggest 1/2" mdf but I went with 3/4" instead.

The drawings show the baffles going perpendicular with the ground, but Phil Bamberg mentioned that maybe it would work to make them perpendicular to the front and rear or the cabinet.  That was a great idea, for minimizing cabinet panel resonance and making assembly a lot easier.

[JohnR]

Wow, nice work!

Pardon my ignorance but how do you cut the angles on the baffle?

[mrhyfy]

+2!!

[mresseguie]

Tell me making your own speakers is easy (I'm pretty gullible.). This is going to look great! 

[musiclear]

Wow, nice work!

Pardon my ignorance but how do you cut the angles on the baffle?

This is a much bigger project than I have ever done before and I had no idea of how heavy these panels and front baffle was going to be.

I have seen people in other projects make jigs and cut baffles like this on a nice table saw and I thought, I have a nice table saw.  Well, apparently a $250 Ridgid is not nice enough because nothing about it was really stable enough to take the weight and maintain tolerance.

I found a custom wood working shop, Jefferson Woodworking around the corner and they have a master craftsman working there who agreed to do the cuts.

He was going to make them on the HUGE saw with a roller bearing rolling table and a 20" blade.   In the end though, he drew some lines on the sides of the wood and after making some rough cuts on the saw, used a belt sander to bring the surfaces down to spec. 

Something I would never been able to do, but his 30 years of professional experience pulled it off.  I mentioned to him I was impressed with his craft, he said, Oh, ya...It wasn't much.  MDF is so soft it comes off like butter."  Nice....

Since I was there, I had them tighten up the tolerances of my other panels also.  That made the assembly a little nicer.

[Vapor Audio]

Something I would never been able to do, but his 30 years of professional experience pulled it off.  I mentioned to him I was impressed with his craft, he said, Oh, ya...It wasn't much.  MDF is so soft it comes off like butter."  Nice....

I bet you could do it 

I'm a master of making due with the wrong tool.  I've done a similar thing by selling a guide using a metal straight edge and clamp that into place, then cut as deep as I can with my hand held circular saw.  It might not go all the way through since you're at an angle, so finish it off with a basic rip saw ... you know, the one that's been hanging on your wall for 20 years unused.  After that it'll be a bit rough, smooth it all out with a rigid sanding block. 

Voila !  And if it's still not as even as you'd like, that's why we have Bondo 

Nice looking work so far.  Is the midrange in it's own isolated chamber? 

[musiclear]

They say, "necessity is the mother of invention" and your probably right.  It was also nice to have these well trimmed and clean pieces come back to me.

I have given that midrange a bunch of thought and I came up with an idea that I hope will work out well.

I have had a love hate relationship with the idea of cabinets at all.  They can give you pin point accuracy as the sound wave is well controlled when compared to an dipole baffle, yet inside the cabinet is a LOT of energy bouncing around and creating havoc. 

Also, for some music I love the sound of dipole baffle, yet there is definitely a reduction in pin point realism with all the energy from the back of the speaker bouncing around the room.

To get around this, I decided to use a design that will be a compromise between the two. I decided to use a 6" thick wall PVC pipe glued to the front and back cabinet with a Scan Speak vent at the end and 4" of fiber glass board to soak up the back wave. 

With this idea, there is virtually no energy bounce off the back wall, because it is open to the room, and there will be virtually no energy going into the room as it will be well damped with the fiber glass board.

I would have liked to have a little more room between the side of midrange tube and cabinet wall, but I figured the total square inches is about the same as the SD of the drivers, so I am hoping that will be enough to take advantage of the volume above the mid tube for total cabinet volume.

Here is the beginning of what that looks like.  I guess  I will see how it pans out.

[Vapor Audio]

That idea will work, just be aware you now have your midrange in a tuned port that will have it's own resonance.  To damp that out you'll add stuffing, but too much stuffing does tend to suck some of the life out of the presentation.  Like I said, it'll work - just be prepared to tune by ear.  Take the time to try quite a few different densities of stuffing in the tube and let your ear decide. 

[jimdgoulding]

 

[musiclear]

This is the back of the front baffle.  It is four layers of MDF.  The first two layers were cut out to open some space behind the drivers.

As you can see, there are biscuits here and in every joined surface.  Some of the veneer is sitting on the bed.  I am going with Curly maple with a clear satin finish.

[musiclear]

That idea will work, just be aware you now have your midrange in a tuned port that will have it's own resonance.  To damp that out you'll add stuffing, but too much stuffing does tend to suck some of the life out of the presentation.  Like I said, it'll work - just be prepared to tune by ear.  Take the time to try quite a few different densities of stuffing in the tube and let your ear decide.

I appreciate that comment and was thinking I could tune the pipe by moving the fiber glass disks forward or rearward to attenuate the node.  I came across this interesting calculator and you can see the resonance's. 

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html#c1






My thinking is these resonance's can be measured at the back end of the tube and the driver will not be effected by it as the flow of energy is out the back since it will be open rather than reflected back into the tube as would be in a closed tube?

Also, I noticed I made a huge error in the previous post and have corrected it.  I confused the term infinite baffle, which I was thinking was open to the room with dipole, which is open to the room.  Sorry if I created confusion with that mistake.  It has been corrected.

[JohnR]

Interesting, I'll be interested to see your measurements and what you find to work best.

[musiclear]

I'm interested also.  Who knows what will happen until I get the mike out and start measuring.

Things have moved along a bit.  Here are a few pics.  It's getting exciting.

If you look through the midrange tube, you can see the cut out on the back for the vent and the speaker connectors.  I decided to go with SpeakOn connectors.

[musiclear]

These are the SpeakOn connectors and vent I am planning on using.

[bladesmith]

Very nice, keep the pics coming.  Looks great.

[musiclear]

Very nice, keep the pics coming.  Looks great.

Thanks.  I appreciate your comment.  This is by far the most complicated build I've done to date.  I'm happy with the way it is going though.  Time consuming beyond what I thought, but at least it is rather fun in many ways.

[musiclear]

Here are a couple pics of the connectors for the back of the speakers.  Each connector caries up to two channels.  The tweeter wire is mounted in the cabinet already and will have to soldered as I install the connector. I used the second channel on the bass wire to carry an additional set of wires giving it the ability to carry the signal more efficiently. I have also got a dual run of the same 14g wire from the amp to the back of the spaker.  Need it....probably not.  Will I hear a difference.....probably not.  Does it feel good to know that it really will do the job no matter what?  Yup.

[musiclear]

One more step under way.  I've changed my mind about the sides and am waiting for more veneer to show up, but I got the fronts glued on.

[JohnR]

Looking pretty nice so far...!