Maurbacs DCR tower

[WernerM]

Well the day has finally come! I took those old Ultra linear towers, and made some sawdust with them.

Towers with sides (front and rear face) cut off and driver holes and 1 port hole on one cab finished...



Please pay no attention to the clutter that currently inhabits my garage... :o

Remnants of front and rear baffles...



Pic looking through the sides the port tube will be shortened from 8" to 5.5", this was just a test fit in the baffle hole...



Back side of baffle with NS6 dropped in it's new home while checking fit...



Backside of Vifa for same reasons...



Front pic of the drivers temporarily resting in their new home...



In this pic, I loosely placed the original grills against the sides to give you an idea of the overall size when completed...

[WernerM]

Re: Maurbacs DCR tower

For those whom are wondering the driver locations are as follows:

Upper NS6: 6" down from top, on center

Vifa BC25: 10.5" down from top, 2" offset

Port on front is 5.5" from bottom on center

Lower NS6: 15" down from top on center

[WernerM]

Re: Maurbacs DCR tower

Okay...

Now for the fun stuff. After carefully calculating an even seperation of the chamber volumes of 2/3 upper, and 1/3 lower, I have come to the conclusion that the seperation partition needs to be 23" down from the top. This gives me an upper volume of 30.58L (after deducting driver and bracing volumes), and a lower volume of 15.29L. I was originally going to mount both ports on the front baffle, however, there just ain't enough room. So, here is my dilemma; I can place the port on the rear (really my only option I can think of) mounted at tweeter level, but on center.

It would look like this, but on center, the black line would be the length after cutting it down...




What I would like to know is if anyone sees an issue doing this with the port for the upper chamber. Final port length would put the end 7 5/8" from the front baffle.

[donradick]

Re: Maurbacs DCR tower

Wowzer - you made some sawdust!
Looking pretty good. Make sure you get some significant side to side and front to back bracing
before you button it up. Ain't it nice to have a router? How'd you do the circles?
Did you (like me) find that the Vifa tweeter was just a tiny bit bigger than 2.75 inches?

[greywarden]

Re: Maurbacs DCR tower

I was going to say something along the lines of "You build boxes funny" but then I read that you had cannibalized the monkey coffins and had a "I see what you did there" moment, but I like it.

[WernerM]

Re: Maurbacs DCR tower

Oh I forgot to mention, when I am done the external dimensions will be 34" H x 8.5" W x 11" D. I will put them on ~6" riser stand so that the tweeter is at ear height while listening in a seated position. I am thinking of making a small rectangular box for the riser, that will attach to a larger base. I was thinking of putting the crossover in this riser area for easy access to for any tweaking later on.

[donradick]

Re: Maurbacs DCR tower

Okay...

No for the fun stuff. After carefully calculating an even seperation of the chamber volumes of 2/3 upper, and 1/3 lower, I have come to the conclusion that the seperation partition needs to be 23" down from the top. This gives me an upper volume of 30.58L (after deducting driver and bracing volumes), and a lower volume of 15.29L. I was originally goin to mount both ports on the front baffle, however, there just ain't enough room. So, here is my dilemma; I can place the port on the rear (really my only option I can think of) mounted at tweeter level, but on center.

It would look like this, but on center, the black line would be the length after cutting it down...




What I would like to know is if anyone sees an issue doing this with the port for the upper chamber. Final port length would put the end 7 5/8" from the front baffle.

I don't see a problem with the upper port like that. Not very many places to put it, once you start trying to figure it out.

[WernerM]

Re: Maurbacs DCR tower

Well actually I used the 2.75" setting, and it is a snug fit. I also cheated and made a new 1/8" hole in the Jasper jig for the Vifa cutout (didn't have a hole saw for it). I am going to use a half shelf brace in the upper section, and a full brace/chamber seperator. I am going to 1/4" dado in the area for the braces, and the edges (think rabbet style) in the side pieces for added stability as well. so 1/4" of the side panels will sit within the enclosure. I cut the enclosure down to 7.5" wide to compensate for this, that way the overall width will end up being 8.5" using the .75" MDF with .25" of dado/rabbet edges.

[WernerM]

Re: Maurbacs DCR tower

For finishing, I was thinking of sanding the original box with the laminate wood ( it looks worse in person than it does in the pictures), and painting it. I think I may use black DuraTex on the sides, and maybe a rustoleum hammered copper paint on the original front, top, and rear. Basically everything that is wood laminate covered right now will be hammered copper, and everything that is new, look at the grills and think of them in black DuraTex...

[donradick]

Re: Maurbacs DCR tower

Sounds like a plan. You seem to overcome woodworking "challenges" better than I do.
Plenty of smokes burned with me standing there thinking "well, just how do I fix that goof up"

[WernerM]

Re: Maurbacs DCR tower

LMAO! Well I actually test cut (and test fit) the holes in a scrap piece first to make sure I was using the right settings. :D

[Wolf]

Re: Maurbacs DCR tower

Typically the 'exit' ports go on the same surface. You should have room below the lower woofer i you use a 2/3 - 1/3 arrangement in one way or another.

How about using an elbow and placing it in the lower chamber through tothe other?
OR- you could use 2 equivalent ports to flank in the spots below the lower woofer.

OR- mount the lower port on the back as well, and cover the front hole with something decorative.
Just some thoughts...
Wolf

[WernerM]

Re: Maurbacs DCR tower

Let me ask this... IIRC the GROT is to keep one port distance away from boundaries. Is that one port distance away from the center of the port, or the edge of the port? IOW the reason I said I can't put the other one on the front, is because the edge of the port (side) will be within 2.25" from the seperation brace. As I understand it, if the port is too close to a boundry, then you effectively lengthen the port, and lower the overall tuning of the chamber. I have always assumed that this rule was from the edge of the port, not the center...

[WernerM]

Re: Maurbacs DCR tower

Typically the 'exit' ports go on the same surface. You should have room below the lower woofer i you use a 2/3 - 1/3 arrangement in one way or another.

How about using an elbow and placing it in the lower chamber through tothe other?
OR- you could use 2 equivalent ports to flank in the spots below the lower woofer.

OR- mount the lower port on the back as well, and cover the front hole with something decorative.
Just some thoughts...
Wolf

Please enlighten me. Is this for aesthetics, or is there a scientific reason for this? If I go below the woofer, that leaves me with 1.5" from the interior lower wall of the port to the seperation brace. do you think this distance is sufficient enough not to cause any real ill effects? In all honesty I would prefer it on the front as well. Reminder, port is 2.25" I.D.

[tc]

Re: Maurbacs DCR tower

Very cool idea! Man, I look at that and think "what an easy way to knock out a MLTL!" Plus, the novelty/cool-factor of reclaimed materials is bitchin!

Props do you dude!