ER18 build (for real this time!)

[capricious]

No ... as you can see, the flared port is about 6" in length, and i cannot cut it further. What i can try is to remove the flare at one end, and even then it'll be a little over the specified 3 1/4". Wonder what the other guys (like skyline_123) did.

 

[mattsk8]

Guess I was a little over zealous, not much done so far. I have the dados all done and had the cabinets all mocked together and everything fits well. I also have 2 of the braces cut out, so now I can use my tracing bit in my router and do the rest. Won't be able to get after these till prob Monday again.

 

[mattsk8]

Tonight I got a bit done, I have the braces all cut out and rounded over. Was definitely a nice day ender bonus, didn't think I'd get to touch these today.

Now I'm still going over in my head all different ideas for a baffle. I can either do a full front, solid cherry baffle and just do the radius at the bottom of the grill, or I can do a solid 3/4" thick baffle that goes around the drivers (what everyone I've seen build these so far has done), or I can do a baffle that goes around the driver's that's satin black (like Jeff's or like most of the Songtowers). Trying to think of other options as well, not a fan of having regrets w/ something this involved at all!!

So far I'm leaning toward either the full front, solid cherry baffle w/ a 1/2" thick grill w/ a radius at the bottom (grill would just cover the drivers, not the whole front of the cabinet); or I like the 3/4" solid cherry baffle that only goes to the bottom of the drivers, w/ a 1/4" thick grill that basically follows the baffle. Decisions, dicisions...

 

[mattsk8]

Can anyone offer suggestions on a removable panel so I can access the xover? My plan is to mount it in the base of the cabinets. I have 2 ideas- either I do a 1/4" rabbet around about a 6"x8" cutout in the bottom center of the rear baffle and put threaded inserts in it, and make a 3/4" thick plastic panel to screw to it (the access panel); or, make a 7"x9" cutout and glue some 1 1/2" wide x 3/4" MDF pieces around the opening, that would give me the 3/4" lip to fasten the plastic panel to (would use threaded inserts here as well) and this way the removable plastic panel would then be flush w/ the rear baffle.

Any other ideas?? Maybe some that are better? I've managed to get away from having to do this w/ my other builds cuz I can access the xovers thru the speaker holes in the cabinets. W/ the woofer braces on the ER18's, I won't be able to do that w/ these.

 

[Swerd]

Can anyone offer suggestions on a removable panel so I can access the xover? My plan is to mount it in the base of the cabinets. I have 2 ideas- either I do a 1/4" rabbet around about a 6"x8" cutout in the bottom center of the rear baffle and put threaded inserts in it, and make a 3/4" thick plastic panel to screw to it (the access panel); or, make a 7"x9" cutout and glue some 1 1/2" wide x 3/4" MDF pieces around the opening, that would give me the 3/4" lip to fasten the plastic panel to (would use threaded inserts here as well) and this way the removable plastic panel would then be flush w/ the rear baffle.

Any other ideas?? Maybe some that are better? I've managed to get away from having to do this w/ my other builds cuz I can access the xovers thru the speaker holes in the cabinets. W/ the woofer braces on the ER18's, I won't be able to do that w/ these.

Although I can't quite imagine exactly what you're suggesting, make sure the cutout and removable panel doesn't get in the way of or interfere with the port, which is mounted on the rear baffle, horizontally centered, with its center 3" above the interior cabinet floor.

Here's another idea I've seen a few times. Instead of mounting the speaker cabinet on a plinth, make a box about the same size as the plinth and tall enough to hold the crossover inside. You can mount the crossover board upside down inside the box and leave the bottom of the box open for easy access. Install spiked feet in the corners or along the edges of the open box.

Make 6 terminals in the back, 2 for the standard + and – inputs, 2 for the woofers, and 2 for the tweeter.

Other than holes for wire terminals to and from the drivers, you don't have to build any large openings in the cabinet.

 

[capricious]

Can anyone offer suggestions on a removable panel so I can access the xover? My plan is to mount it in the base of the cabinets. I have 2 ideas- either I do a 1/4" rabbet around about a 6"x8" cutout in the bottom center of the rear baffle and put threaded inserts in it, and make a 3/4" thick plastic panel to screw to it (the access panel); or, make a 7"x9" cutout and glue some 1 1/2" wide x 3/4" MDF pieces around the opening, that would give me the 3/4" lip to fasten the plastic panel to (would use threaded inserts here as well) and this way the removable plastic panel would then be flush w/ the rear baffle.

Any other ideas?? Maybe some that are better? I've managed to get away from having to do this w/ my other builds cuz I can access the xovers thru the speaker holes in the cabinets. W/ the woofer braces on the ER18's, I won't be able to do that w/ these.

You can make the bottom removable. To put it simply, it would be just like a removable front or back baffle you see in many speakers. You can cut two 1" strips of ply and glue it near the bottom about 3/4" away from the end. You can then screw the bottom panel flush into this strip. The bottom panel will hold your cross over, and can easily be removed.

 

[mattsk8]

Although I can't quite imagine exactly what you're suggesting, make sure the cutout and removable panel doesn't get in the way of or interfere with the port, which is mounted on the rear baffle, horizontally centered, with its center 3" above the interior cabinet floor.

Forgot about the port being in the way. For my idea to work, I'd have to put the cutout above the port and remove the port to access the xover (which will hopefully never need to be done!).

Here's another idea I've seen a few times. Instead of mounting the speaker cabinet on a plinth, make a box about the same size as the plinth and tall enough to hold the crossover inside. You can mount the crossover board upside down inside the box and leave the bottom of the box open for easy access. Install spiked feet in the corners or along the edges of the open box.

Make 6 terminals in the back, 2 for the standard + and – inputs, 2 for the woofers, and 2 for the tweeter.

Other than holes for wire terminals to and from the drivers, you don't have to build any large openings in the cabinet.

You can make the bottom removable. To put it simply, it would be just like a removable front or back baffle you see in many speakers. You can cut two 1" strips of ply and glue it near the bottom about 3/4" away from the end. You can then screw the bottom panel flush into this strip. The bottom panel will hold your cross over, and can easily be removed.

I love both of these ideas but I'm leaning toward capricious' idea just because I wouldn't have a fortune into terminals going that route! Although, those terminals would look pretty cool. Thanks for the input!!

 

[David LR]

As far as I know, there's nothing wrong with putting the crossovers vertically on the side walls, in the woofer chamber. That's what I'm planning on doing unless someone tells me that's a big mistake. I believe one of the builders in the original thread handled it that way. That way you still have access. Of course, if you want to put them lower, I'd want an access hatch also.

I did build one small speaker with a completely removable baffle, used the rabbet method with corner braces & threaded metal inserts. Worked fine, but what a lot of work. I only did it to see if I could do it. They were my daughters speakers, I doubt very much she will remove the baffle just to see what's inside !

 

[mattsk8]

As far as I know, there's nothing wrong with putting the crossovers vertically on the side walls, in the woofer chamber. That's what I'm planning on doing unless someone tells me that's a big mistake. I believe one of the builders in the original thread handled it that way. That way you still have access. Of course, if you want to put them lower, I'd want an access hatch also.

I did build one small speaker with a completely removable baffle, used the rabbet method with corner braces & threaded metal inserts. Worked fine, but what a lot of work. I only did it to see if I could do it. They were my daughters speakers, I doubt very much she will remove the baffle just to see what's inside !

If it'll work I'm all in, all about the easy route! My only fear was that I wouldn't be able to get the crossover through the woofer hole, that it would be too big to fit in around the brace. Guess I'll build the xover as small as I can and play w/ it a little before I glue everything up. No sense to me in making the removable baffle if I don't have to.

 

[David LR]

I've only actually assembled two crossovers, with each I put the tweeter & woofer circuits on separate boards. The boards can be kept smaller that way, although, the real reason I do it is because using a common ground & combining the circuits on one board just confuses me at this point. !

If you search through the original thread, I think you'll find that one of those guys did it this way & Swerd said no problem. I'm waiting for his confirmation on that though. I used to be concerned with overheating since the crossovers will be buried in the dacron stuffing but I guess that's not really an issue.

Found that info, on page 15 of the original thread, Jeff G wants to put the crossover behind the woofers, Swerd said "no problem with that", so, that's what I'm going by anyway.

 

[Swerd]

The way I imagined building this speaker, is to install the crossover boards and wires before gluing on the front baffle. That way it will be easier to screw it in place – such as on the rear or side vertical wall. Any place below the polyfill is fine, as long as it isn't close to the inner opening of port tube where it might interfere with air flow.

I used to worry about having access to crossovers after building a speaker. With crossovers designed by Dennis Murphy I have never needed to modify them, so why take the extra effort? If for some reason you find the tweeters a bit too bright for your taste, take the tweeter out and add a 1 or 2 ohm resistor just before the + terminal behind the tweeter. You don't need to pull out the crossover board to do this.

The only time I ever had to pull out a crossover board for repair was when a heavy inductor coil pulled loose and broke its electrical connection. Back then I was lazy and thought hot melt glue was enough to secure things to the board. Now I use at least 2 heavy 8" long cable ties to mount the heavy coils to peg board. The caps and resistors are not nearly as heavy and usually need only 1 cable tie. I don't bother with any glue at all.

When I connect wires to the board I loop them through 2 holes on the board in an S shaped pattern for stress relief. I also use cable ties, solder, and crimp on insulator caps just to make certain that nothing pulls loose.

 

[David LR]

Swerd-

So, putting the crossovers below the polyfill is the best way ?. Anything actually wrong though, with putting it in the polyfill chamber ? In my inexperience I start thinking things like it takes up too much room, it's going to overheat, etc., although it takes up room no matter where you place it I guess.

Also, there are lots of smaller sealed speakers with both polyfill & crossover inside. I guess I just don't have enough confidence in my crossover abilities to deny myself corrective access.

Dave

 

[mattsk8]

Swerd-

So, putting the crossovers below the polyfill is the best way ?. Anything actually wrong though, with putting it in the polyfill chamber ? In my inexperience I start thinking things like it takes up too much room, it's going to overheat, etc., although it takes up room no matter where you place it I guess.

Also, there are lots of smaller sealed speakers with both polyfill & crossover inside. I guess I just don't have enough confidence in my crossover abilities to deny myself corrective access.

Dave

I've heard it doesn't make a diff, that's where I put them on the statements; right behind the woofers. If I'm sure they'll fit through the woofer holes that's what I'll do w/ these as well. I don't have enough confidence in my xover building abilities either! I was glad I had access to them on my Tritrix after I completely disassembled them to finish the cabinets. I lost track of the + n - on them and had to go to the xover to figure it out. Thought I had them hooked up right but when I powered them up they sounded like a trasistor radio! Long, boring story but I figured it out.

As far as my build goes I'm at a bit of a standstill . Can't move forward untill I come up w/ an idea I'm happy w/ for the baffle. I'm afraid if I do the standard 3/4" baffle out of solid cherry it'll look funny w/ a grill on it. W/ a grill that would stick out a full 1 1/4" and to me that seems excessive. I could make the driver baffle only stick out 1/2" and do a 1/4" grill but that might look more modern than I want it to, I want nice roundovers. I have 2 ideas so far- either I make it so the driver baffle only sticks out 1/4", then w/ the grill on it would only be a 3/4" protrusion (1/2" thick grill frame); or I just make the whole front of the speaker solid and put a grill on it that only covers the speakers.

I like the first option but I'm still going over ways to make it work; the second just seems kind of boring.

As far as final finish, I'm going for this look. I love cherry and this desk always appealed to me. So much for bookmatching . It's in my parents house and they had some drywall work being done that day (the reason for the dust!).

 

[Swerd]

Swerd-

So, putting the crossovers below the polyfill is the best way? Anything actually wrong though, with putting it in the polyfill chamber?

It sure is tough being considered an internet guru, every word I say is scrutinized intensly .

So why did I say "Any place below the polyfill is fine"? I'm not sure I had a specific reason, much less a good one. I guess I was thinking that there is plenty of room to mount the crossover board in the cabinet while still avoiding areas near the port tube or areas that will be filled with 17-18 ounces of polyester. I don't think putting the crossover in the polyfill area would cause any problems, but with other areas available why not avoid the polyfill area?

Unlike a small bookshelf speaker, the good thing with the ER18 MTM is that the cabinet is large and you have several good places to mount the crossover board(s).

Mattsk8 - I'm confident you'll think of some good looking way to do the front baffle. You seemed to come with good ideas in your other builds.

 

[David LR]

It sure is tough being considered an internet guru, every word I say is scrutinized intensly .

Well now, somebody's gotta be the guru ! You are qualified, I am not.

Sorry, no pressure intended. I'm sure I obsess over things that don't need to be obsessed over.

I appreciate your help & input.

David

 

[mattsk8]

I finally have an idea on how I'm going to finish these, but I won't try to explain it cuz it'll just confuse me and anyone reading it ! (Don't ever sign me up to write an owner's manual for something, you'll want to kill me before you figure out just what I'm saying!) Now all I need is time. Hopefully this coming week I can get back into them.

 

[mattsk8]

I suck . I need more time! I even already have my next build; going to build some speakers for the sanctuary at the church I go to (that'll be another thread!). I've also decided I'm going to tackle a complete design and build for my HT system; most of you know where I'm at w/ that. I was going to do the Zaphs but decided to just try a totally new design (w/ lots of help from you guys, God help us all!). It'll be a learning experience for sure but I think I've used enough of everyone else's designs at this point that it's time to try to give something back. Might end up a monumental waist of money and be a total disaster; but maybe it'll work out

 

[David LR]

OK, so, you're going to build speakers for your church, AND you're going to design your own ? More power to ya, but, NOT before you finish your ER18's, right ??

 

[mattsk8]

OK, so, you're going to build speakers for your church, AND you're going to design your own ? More power to ya, but, NOT before you finish your ER18's, right ??

For sure I'll finish the ER18s first! Right now I have to make the veneer for them and thats a bit of a timely process, need a whole day for that. Hoping for Saturday if it rains, if it doesn't rain I'm going to be on our boat w/ the wife n kids.

 

[David LR]

Regarding veneer, it looks like the dimensions of the ER18 don't play nice with standard paper backed veneer sizes. I would like to run the veneer with the grain running vertically, up & over the speaker. The way I see it (44.5+44.5+9), that equals about 98", standard veneer is 8' or 96" long unless it's special order, standard veneer isn't long enough to do the job. Hope I'm explaining clearly here.

I've thought about putting a piece of trim, say 1.5" x 1/4" thick, on the lower end of the cab, that would take up some room, but , not sure how that extra trim is going to look with the floating shadow piece effect.

Any thoughts ? When you make your own veneer, how thin can you cut it ??


Dave