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Discussion Starter #21
As promised - unboxing photos.
 

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Discussion Starter #22 (Edited)
First Cuts

Got the parts cut to basic sizes today. Had Home Depot cut the big sheet down to manageable sized pieces taking care to keep the factory edges in usable positions for the following cuts. I marked all the factory edges with an "E".



Before I started I checked the alignment of the saw. I use a Mag DRO Miter Slot BAse Table Saw alignment tool. It holds the shaft of standard calipers and is more than solid enough for wood working. I got the blade aligned to .0035" error front to back at full extention.



While the blade was up I checked it for square.



Then I used the Mag Dro setup again to check the rip fence. It was out .011", a little more than I'd like but usable. (I like the outfeed end to be a little open anyway, but ~.003 or .004 is enough to help prevent binding and burning.)



Then it was time to do rough rip cuts to get the 3 sheet sections from HD down to the approximate sizes for the all the parts. Take care when you make these types of preliminary cuts. They don't need to be real accurate in width, over wide by some margin is fine. What you need is a STRAIGHT cut. The edges you make here will be the edges you use later. Focus on the interface between the work piece and the fence. Don't ignore the blade. When you ignore blades they tend get their feelings hurt and are more likely to bite fingers and other fleshy things, but the most important thing is the work against the fence. Maintain that and good down force and what's happening at the blade will work out right. Focusing on the cut is a rookie mistake that makes for un-parallel cuts.



From there it was time to rip to final width. Measure twice from the fence to edge of the carbide tooth on the blade. Then cut all of the identical width pieces in a batch. Move from group to group till all the widths are complete.

When all the ripping was done I mounted the crosscut sled and got a block of wood and a clamp for a stop block. For each length I set the piece in place, line up a cut mark to the saw tooth, then set the stop block. Re-check the length to the cut mark and make the cut. Then use the stop block to make the remaining cuts for identical pieces. Stop blocks are best used on the kept end as opposed to the off cut. This allows you to adjust for the final length (cut long then small corrections till right). If the stop block is on the off cut (sometimes it's unavoidable) you need to measure for each cut to prevent errors that rise from inconsistent lengths of the raw pieces.



When I was done I checked the widths and the lengths of the sides and the backs for consistency.



The sled/stop block setup makes for quick work on things like brace pieces.



All done with the sizing cuts.



Tomorrow I'll get the detail cuts marked off and completed.
 

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Discussion Starter #23
Made some progress today. Back cuts on the sides and all the rabbets and dadoes. I had to quit early to attend a church function I had forgoten about. I have pics I'll try to post tomorrow.
 

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Discussion Starter #24
Creating the back cut for the front panel.

I used a strip of ½" MDF to measure for the notch cut in the sides that will receive the front panel.



Then thought some more and used the piece of ½" to act as a spacer for setting a straight edge guide, in this case my 4' level.



It made for a nice straight cut right where it needed to be.

I could have done the same for the other pieces but instead I used the first piece as a pattern and did the rest with my plunge router and a flush trim bit. This insured a perfect match with the exception of the rounding on the inside corner which was cleaned up with a sharp chisel.



Four sides ready to receive rabbets and dadoes. (In retrospect I should have cut the rabbets and dadoes first as cutting the notches made for some difficulty in registering the pieces against the fence of the sled)



One might think that the dust that resulted would be a problem. That dust and a little wood glue will make a perfect filler later. (Yes, I'm cheap) The first bag shot was from just the first routed piece. I think that I'll have enough.




One more note. A few years back I bought a cheap ($100) wood working bench from Ace Hardware. It's a 5' light weight toy of a thing that has non-standard, ⅝" dog holes, and pathetic little wood dogs that barely get the job done with lame front and end vises. I've never regretted the purchase. Sure, I'd like to have a really nice solid maple 7 footer with nicer vises and standard dog hole sizes but this thing has been just what I needed for jobs like this one.



Next up - Rabbets & Dadoes
 

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Discussion Starter #25 (Edited)
Long rabbets on the rip fence.

The long rabbets are done with a sacrificial fence (3/4 ply clamped to the table saw fence - not shown) and and dado stack set up for an over sized width. In this case all 6 ⅛" cutters and chippers plus the 3/32" chipper.



You should always engage ALL the threads of the arbor nut.



The stack is lowered fully into the saw, the sacrificial fence is then positioned to overlap the stack by about ⅜". The blade is then started and slowly raised till the proper cut depth is reached. Test it on a piece of scrap.



Once you have the depth correct check the width.



Make incremental corrections till the width is correct. I'm calling this good.



Proper prep makes for quick work on the rabbets. Always use push blocks even when the blade doesn't come through the top of the work piece. (not shown - the rabbets on the side pieces)

 

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Discussion Starter #26
End rabbets & dadoes.

For end rabbets and dadoes going over wide isn't an option. Setup will determine if you have a good fit or if the dado/rabbet is to loose or too tight. Too loose and you lose the alignment qualities you're looking for. Too tight and rabbets have visible overlap and dadoes either won't assemble at all or may even split the material at the joint.

You need to assemble the dado stack first using the fractional ID's of the blades and chippers, test for fit on scrap from project stock and make adjustments, usually with the supplied shims. I started with the 6 ⅛" blades/chippers and needed to make 3 adjustments before I was happy. I consider a good joint to be a good friction fit that can be disassembled by hand with light effort. If inverted the captured piece should remain in the dado.



Setting up for the end rabbet cut is a simple matter. Run the sled to place the fence over the blade and attach a stop block on the far side that just kisses the blade teeth. This will achieve the desired cut virtually every time.



For the dado lining up all the slots will be critical during assembly so the position needs to be referenced to a common edge. In this case the front doesn't go all the way to the top so the bottom was the only choice. A strategically placed stop block works all around.



One last detail for the cuts. Check the length of the brace pieces. They need to be the same length as the space between the long rabbets on the fronts and backs.



That'll work.
 

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Somewhat off topic.
I've been putting off building a crosscut sled for my table saw and this is a perfect reason to go ahead with it. If anyone is interested in it, sing out, and I'll include it in this thread.
Otherwise i'll keep it to myself.
Hi.
Saw your post on the Routerforum. If you include something about the sled, I'd be interested.
Mark
ps
I bought an Infinity ServoStatic-I set in the 70's.
The owners at the then startup company, were true innovators.
 

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Discussion Starter #28
Links to everything are in the first post. I did three construction posts on the sled.
 

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Discussion Starter #29 (Edited)
Not a lot of progress during the week. Work gets in the way. I manage to do a little prep and research.

I'm going to use a template to mark the baffle positions for the drivers and the attachment points for the grill. This way the grills have the best chance of being interchangeable. The centers of the drivers and the attachment points for the baffle I'll drill with the smallest brad point I have and I'll use it as a transfer punch. The current plan is to use rare earth magnets to hold the grills in place.



I checked the crossovers against the middle partition and as I had guessed both would not fit.



I'll mount the tweeter xover on the side near the tweeter. This has the bonus of allowing the inductor to be mounted so that the axis is at right angles to the other two. I was already planning to attach them both with screws (double sided tape was applied by Madisound - nice touch). I want to be able to remove the xovers in the event we don't sell and stay here. If so I'll need to build a stand mount/bookshelf version of the enclosure to fit the space.
 

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Discussion Starter #30
Weekend progress:

First up - the terminal cup. The cup has a nice rounded edge profile that would look better if surface mounted so I ignored the recess and setup for a simple through cut. All I needed was a pattern and a flush trim bit for the router.

Making the pattern was easy enough - a few 1" strips of ¼" MDF taped together around the body of the cup.



Then attach the pattern to the back. I made center line marks on both the location on the back piece and the pattern and used them for alignment. Attach with brad nails or double sided tape (if tape is used, watch the amount of lateral force applied during routing as the pattern could shift.) Once the pattern is in place use it to locate a hole large enough for a jigsaw blade in each corner and cut the bulk of the waste out with the jigsaw. Leave a little waste to be removed by the router.



When matching the radius of a part to a bit always use a bit with an equal or, in in this cas, lesser radius. just be sure if using a lesser the tighter corner will be covered and unseen. Make certain there is sufficient clearance below the work by raising the piece on spacers (in this case some ¾" scrap). Clamp the work down.
Set the depth of the bit to allow the cutter to just extend past the bottom edge of the work piece and insure the bearing will make good contact to the pattern. Move clockwise around the hole keeping the bearing against pattern.



When done the pattern is removed. The brads can be pulled but will require filler so I opted to use a fiber reinforced cutoff wheel with my Dremel. Personal note: I use only the fiber wheel. The cheap carbon wheels shatter too easily. Since the brads were a little long I had some excess on the back side before I started the cut. The Dremel took care of that, too.



Nice fit.



Port:

The port needed a recessed cut for the flange. A plunge router is the best tool for getting an accurate recess depth. Most plunge routers have some sort of depth stop adjustment. The Bosch I own (model 1617) uses a stop rod/rotating stop turret arrangement.

With the bit chucked into the collet, set the router on a flat surface. Plunge the router till the tip of the bit is just touching the flat surface and lock it into place.


Sometimes it's possible to use the work piece itself to set the depth but in this case the piece interfered with parts of the router and would not set straight.


Here's where a set of calipers can be used. Just take a measurement of the flange thickness and use it to transfer the dimension to the stop. Zeroing the calipers at the measurement will allow for easily seeing if the calipers shift during the transfer.


I'm using the Jasper 240 circle jig for the circle cuts. When using a circle jig, use a backer board. I used a piece of ½" MDF. Firmly attach the backer so that the completed cut will not compromise the attachment. I use brads so I placed two near the center pivot and two outside the outer cut line. My first cut is the inner dim. This way it's easy to see when the flange recess cuts are complete. First the inner through cut at recess depth, then the outer flange dim., then step the diameter down incrementally till the flange recess is complete with a clean bottom. Reset to the inner through dim and step the turret to get incrementally deeper cuts till the cut goes through.


The only problem was with accepting the dimensions from the documentation. It left too much of a gap. Lesson learned.


The backs are done. Next post the baffles.
 

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Discussion Starter #31 (Edited)
The baffles.

I have my template lined up with a baffle. Use the ⅛" drill bit used to make the holes in the template as a transfer punch to locate the hole centers on the surface of the baffle. Be sure to transfer ALL holes at the same time.



Drill the holes out to ⅛" for the pivot pin on the Jasper jig.



Mount a backer board and use the same process used with the port hole in the back. When transferring the flange thickness to the router stop be sure to compress the gasket. This will insure a flush registration between the driver and the front surface of the baffle. When you compress the gasket trying to remove the calipers will probably tear the gasket so take note of the measurement, loosen the calipers and reset the measured value on the calipers. Then lock them down and zero as before.



Nice. These are acceptable. BTW the drawing specs the outer flange dim as 5½" - nope - 5-7/16". that was just 1/128" over the 5-55/128" measurement I took with the calipers. No ugly gaps this time. The tweeters worked with the dims from the drawing with no play. Measure - YMMV.

Full disclosure notice: I messed up on the first baffle on the last hole and had to re-cut the blank. That's why the first cut pics show pencil lines but the finals don't. edit: Those were the wrong pics anyway so I deleted them.:whistling:
 

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Impressive job on the accuracy of your cuts!!

I will be building these speakers some time as we'll, so I can't wait to see them finished and read a review about how they sound :)

I just ordered 4 ZA5.2 for my surrounds since I have decent fronts and center, but eventually these towers will replace my current ones.
 

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Discussion Starter #33
Sorry for the lack of updates but we've been in negotiations for selling the house and buying the new one. I've made some progress and taken some pictures but haven't had the time to upload the pics and generate a post. I need to get these finished to a point they can be easily transported to free up the garage to be packed up.

I'll post progress as time permits.
 

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Discussion Starter #34
I've said that I'm going to set these up to accept bi-amping. As I've read around various forums it's clear that passive AVR bi-amping doesn't get much support. Can't say that I can argue since I've never bi-amped before and to my knowledge I haven't heard a system where the practice was used. I had a little time at work during lunch and decided to work up a speadsheet of the reactance values throughout the crossovers and see if that would shed any light on the subject.




At the end of each section (Tweeter/Woofer) I've calculated the total impedance presented to the amplifier for that section and the power the amp would develop to drive that load. For a power reference I used the Pioneer spec for my SC-71 into 4Ω - 180w. I then calculated a peak voltage that would exist at that power and 4Ω load - 37.9V. I used that Peak voltage to calculate the the power developed by the amp at the various frequencies. I know that the 180w figure probably has more to do with UL ratings than an accurate estimation of the power supply rail voltages but it's all I had to go on.

The kicker here seems to be C11, the little cap John (Zaph) inserted to tame woofer cone breakup. It also holds the woofer crossover overall impedance down at higher frequencies which forces the amp to develop the power to drive it. If not bi-amped this power (total unused as audio) would just bleed off power that could otherwise be allocated to high freq. transients. Not saying it would be an audible improvement but at the very least it would reduce the power demands on the front channels and redistribute them to channels that were otherwise unused. That might add a couple of more years of life to the box.
 

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Discussion Starter #35
First, I'm sorry but no pictures. Selling and buying houses is taking most of my time.

I have completed the speakers. I primed them and as previously stated I gave them two coats of black gloss enamel with the expectation of giving them two more coats of satin clear lacquer. With just the gloss they look terrible. The humidity was up and every single brush stroke is visible, no leveling at all.

But all of that may be academic. They sound good but they don't sound as good as my Infinity's. Don't get me wrong I wasn't expecting them to blow the Infinity's out of the water, but they don't come close enough to warrant using them as a replacement. To tell the truth I had my doubts coming in but I thought I'd give it a shot. The footprint difference was attractive. Also the Infinity's are a little long in the tooth (they stopped making them in 1982 I believe) and it can only be a matter of time before the EMIT's go out.

I have the Zaphs setup in my living room now and they will run non-stop till we move (very soon, now). That should give them the time to open up enough to let me know if they'll meet the challenge. I have to admit, I have serious doubts.

All that said they do sound very good, especially considering the size of the drivers. The detail is excellent and the tonal balance is very good, just a little treble bright for my and my wife's taste. I'm expecting them to open up a little after they break in some and I'll give them another chance, but if they don't pass muster they'll be a gift for my son.
 
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