ER18 build (for real this time!)

[mattsk8]

To measure inductance you need an LC meter, such as this Digital LC Meter 390-570. A few years ago, I found a less expensive one on Amazon. Poke around to see what you can find now.

All I do is unwind the coiled wire until the meter (attach the leads to both ends of the wire) reads the desired inductance value. As wire is unwound from the spool, it no longer acts as an inductor, so you don't have to cut wire until you have the value you want. After making the cut, I use sand paper to scrape away the lacquer coating from about ½" of the end of the wire so I can solder later.

About the burn marks where you cut the recess for the drivers. I usually use a black marker, like a Sharpie pen, to blacken any visible part of the recess cut. Maybe that will cover the burn marks without sanding.

Guessing that gadget does something that my auto ranging digital multi meter doesn't do. Maybe a future tool purchase but I need to hold off from it for now. I have to get a few things from Meniscus (binding posts, and threaded inserts) so I'll either just get the .06mh ones from them or have them unwind the ones I have. Thanks again for the input Swerd!

By the way, nice look on the baffles, I like how you stopped the radius & than transitioned to the horizontal section. Must have been a little tricky to do.

It was actually pretty easy (ish). I wanted that channel under the baffles to tuck the veneer under as well, so I made the baffle w/ the radius 1 1/2" less wide than I wanted it, then trimmed around it w/ some 3/4" pieces. Basically I cut the baffle, then made the radius on the bottom, then routed the 1/4" channel into the bottom back side of it, then glued the 3/4" pieces to the top and sides of the baffle. I'll get a better pic when I finish them and hope it'll make sense then!!

[mattsk8]

Question about the xovers. In Swerd's writeup it says to use a 50 ohm resistor. I ordered the parts per the list on Swerd's write up and have 2 25 ohm resistors. My question is...

Would I hook these up so it goes- line into one resistor, then out then back into the other resistor and by the time it comes out of the second resistor I have 50 ohms of resistance?

That might seem like a really dumb question to a lot of you but there is one other option, just making sure I was doing this right. Thanks for any help!!

[Swerd]

Question about the xovers. In Swerd's writeup it says to use a 50 ohm resistor. I ordered the parts per the list on Swerd's write up and have 2 25 ohm resistors. My question is...

Would I hook these up so it goes- line into one resistor, then out then back into the other resistor and by the time it comes out of the second resistor I have 50 ohms of resistance?

Hook up the two 25 ohm resistors just as you described, in series with each other. To get the total resistance of resistors in series with each other, just add up the resistance of each individual resistor.

[mattsk8]

Hook up the two 25 ohm resistors just as you described, in series with each other. To get the total resistance of resistors in series with each other, just add up the resistance of each individual resistor.

Thanks!! Xovers... are done

Curious if someone can double check these and make sure they're right before I box them in.

Tweeter xover-



Woofer xover-

[Swerd]

It looks good to me.

I can't read every value printed on the components in your photos, such as for the resistors, but I trust that you read them and got them right.

[mattsk8]

Since I put pics of everything else, I may as well put my screw ups on here too.

Planned on putting my threaded inserts in last night but had to rewind a bit. Woofer holes are great, but anyone that reads this and uses my tweeter hole dimensions is going to be pretty frustrated w/ me .

When I originally measured out for the tweeter cutout I just took a dial caliper and measured the cutout for the tweet based on the width of the tweeter's back side. The problem is, the tweeter's are kind of square and you can't make the holes round; if you do that (which I did) it puts the 4 mounting holes 1/16" from the edge of the cutout . My fix for this was to take a rabbeting bit and rabbet out 7/16" of the tweeter hole on the back side of the baffle. Then I cut out a piece of 3/4" mdf and glued it in. Hopefully (if I have time) this evening I'll make the correct cut out in the newly glued piece that will allow for my threaded inserts.

Pic of the repair piece glued in on the backside:



And a pic of it from the front:



The bad part of all this is that I've installed these same tweeters in the Statements once already and didn't make this dumb mistake! One of those brain dead moments I have when I'm trying to hurry I guess . Just glad I found a way to fix it w/out having to make the entire front baffle again !!

[David LR]

Thanks for posting the screw-ups too. It illuminates possible pitfalls for other builders plus gives them good creative solutions if it does happen. Yeah, those brain dead moments, sometimes I think we all just go on auto-pilot, not realizing we, (me anyway), have to be aware & thinking all the time or I will screw up !

Those Cherry baffles are going to look really nice !

[jinjuku]

For odd shape tweeters (like ribbons) I take calipers and transfer all the different measurement points to a piece of heavy construction paper.

I connect the dots. Over cut the diagram out. I then spray adhere it to 5/8's or 3/8's brown board and cut out with a fine tooth jig saw. I now have my template showing the hole and use double sided carpet tape. I then use a bearing guided up cut spiral bit to knock out the hole on the table router.

[mattsk8]

For odd shape tweeters (like ribbons) I take calipers and transfer all the different measurement points to a piece of heavy construction paper.

I connect the dots. Over cut the diagram out. I then spray adhere it to 5/8's or 3/8's brown board and cut out with a fine tooth jig saw. I now have my template showing the hole and use double sided carpet tape. I then use a bearing guided up cut spiral bit to knock out the hole on the table router.

Thanks for the tip, templates are the way to go for sure. I have tons of 1/4" thick plastic up at work (I work for a plastic recycling plant) that I can make them out of.

[mattsk8]

All fixed . There's a lot of debate over whether to use threaded inserts or just use pan head wood screws- I'm all about the threaded inserts. From building subwoofer boxes for cars, I learned the problem w/ woodscrews in MDF is that if you pull the drivers out and put them back in more than once or twice you end up w/ screws that don't hold anymore. W/ the threaded inserts, as long as they're installed right, it's generally good forever. This is a good thing for me because I like to totally assemble the speakers so I can listen to them before the final finish; which means I put the drivers in and pull them out a couple times at least. They do take quite a bit of time to install, but to me it's worth it. If I didn't have a drill press, it would probably be different though just because getting them in straight w/ a hand drill would be tricky.

I didn't make a template for these. The cutouts were totally done by hand w/ a 1/4" bit in my router so the holes are pretty crude, but fully functional. Kind of looks like the bat signal. The holes in the statments I built are perfect so I think I'll use those to make a template when I take them apart to finish the cabinets.

Pic of the backside w/ the inserts installed:



And a pic w/ the screws finger threaded in to make sure nothing went south when I drill the holes: