The BaSSlines (was High Sensitivity Design)

[dlneubec]

Hi Ed,

What are you creating these days (besides wood panels for Paul)?

I kind of like the baffle edges being defined by the rough edges, but it would be nice to be able to sand/buff the roundovers around the drivers smooth, so all the wood behind is visible.

BTW, did you try that polish out? I have a car-type buffer that I got from Sears that may work, if I can come up with the proper material to use for the buffing.

[cjd]

Dan,

There are a whole pile of buff compounds and wheels available specifically for working with plastics that I had access to back when I was at school - all sourced from Rio Grande - that'd be a jewelry/metalworkin supply house. I don't recommend you even attempt any way other than the right tools.

Looking superb as they are, but I agree - it would be nice to polish up the roundover at the drivers.

[dlneubec]

I just read this online in some googling in regards to polishing polycarbonate:

"Polished edges may be achieved by solvent polishing. After sanding to remove all the tool marks, dip a cloth in a solvent such as methylene chloride and carefully wipe the sheet’s edges. Do not allow the solvent to drip on the sheet face as discoloration will occur."

I don't know under what name methylene chloride sells, but it might be worth testing on a sample piece to see what it does do, if ne can find it locally. I might even try a wipe down of acetone on a sample piece.

[Dennis H]

Methylene chloride (aka dichloromethane) -- wear a respirator and keep it off your skin. POISON.

[EdL]

What are you creating these days...?

I had a second project this weekend along with Paul's. Scott Lindgren (aka Scottmoose) worked up a back-loaded horn enclosure using the Dayton DVC 8" sub. I got it assembled for some Sunday night listening and I'm very pleased. Thanks go to Scott for indulging me.
I'll gather up some supportive info for a thread.

Ditto on Dennis' caution, get the rubber gloves and all the personal protective gear out.

I haven't polished the dust cover as of yet.

[dlneubec]

I tried some acetone and also some tripolene paint thinner and they didn't appear to do anything to the polycarbonate. I'm not sure where Methylene chloride can be purchased, even if I wanted to try it out.

I also tried a synthetic abrasive flap wheel in my drill and it actualy did a pretty nice job on smoothing out the roundover I made in a test piece. Before I'd use it on the finished baffle roundovers, I would want to mask the adjacent flat surface, just in case of a slip. It might work to smooth out the roundovers and make them more translucent. It has too much grit to actually get it to transparent, though I think it might be an acceptable solution.

[Paul Ebert]

Dan, you might find that using heat to melt it to a polish works easier once it is at the translucent phase. I used heat polishing on my DIY turntable plinth and, with some practice, it worked out well. I found that the less the heat had to do, the easier it was to avoid overheating.

YMMV, of course.

[dlneubec]

Paul,

What kind of heat did you use?

I used a propane torch, but I wonder if a heat gun or maybe a pencil flame butane torch might be more appropriate. I don't believe the pencil flame butane gets as hot propane and you can really make a fine flame so as to be precise in what you heat. The heat gun would not be as precise in its delivery, but you could dial in the heat and use a consistent temperature, once you figured out what the heat setting was.

[Dennis H]

I was wondering if you could use micro mesh and liquid polish on polycarbonate like you can on acrylic -- it's how they take scratches out of aircraft windows. This place sells the materials ($$) but they caution it doesn't work as well on polycarbonate because it's so soft. Clicking around the site is somewhat informative.

http://www.sisweb.com/micromesh/acrylic_plastic_kits.htm

[dlneubec]

I've got some synthetic abrasize flap wheels (180grit) as well as felt and cotton polishing wheels that all fit in a 1/4" drill coming from MSC to try out. We will see if they are of much help.

The one flap wheel I do have and mentioned above is quite worn out. It is from 3M, bu is around $35 for one, so I'm looking for a cheaper alternative. It could be that if I can get the roundovers to a more translucent stage with abrasives, a little applied heat will finish the job, as Paul suggests.

[cjd]

Using the right buff compound is the key. That and keeping the heat away.

[Paul Ebert]

I used a propane torch. I was polishing 1 inch thick sides, so a wide flame was good, actually. I would try a heat gun on some scrap to see if it gets hot enough. I would think it can.

The nice things about using heat is that once you get the hang of it, it is very quick and the result is perfectly clear. But, before you get the hang of it, it is easy to overheat and get bubbles. Also, it is possible to set the acrylic on fire 8O . That happened to me a few times. The flame is not very intense so it's easy to blow out, but where there's flame, there's bubbles.

[Dennis H]

Also, it is possible to set the acrylic on fire

Dan's using polycarbonate (I'm sure you knew that.)

[dlneubec]

I wanted to post a step by step process to show how I did the baffles for this project, both the bass bin and open baffle mid baffles. This post will cover the bass bin baffles. Sorry it is so long!

Bass Bin baffles:

After glue up of the baffles, I cut the baffles down so that they were within about ½” of the final width, making sure the center stripe stayed centered in the baffle. I used a portable circular saw with clamped guide piece. The bottom of the baffle was cut at an 8º angle on the table saw so that it would match the angle of the bottom of the box.

After clamping the baffle to the box, making sure the center stripe was vertical and centered; the edges of the box were marked from the back side of the baffle. I used these marks as guidelines for cutting the baffles, which was cut about 1/16” wider all around to make up for the veneer depth. I cut the baffle on the table saw, using an angle guide along the rip fence. This could also be done by hand with a circular saw and clamped guide piece. I might have used a flush trim bit in my router, but I had none that were deep enough to trim the 1-1/2” depth.







After the baffle had been cut to fit the box, I marked, counterbored and drilled the locations for the cap head screws that would go through the baffle to hold it to the box and also marked and drilled the location of the center of the woofer. I used a forstner bit for the counterbores and a drill bit larger than the cap head screw shaft so there is room for wood movement and a less than perfect match with the threaded inserts.

The location for the center bottom protrusion on the baffle was marked and using a 45º chamfer bit, I routered a ¾” chamfer up to those points. This was done using a router table, but could be done by hand. I recommend doing it in stages to build up to the ¾” depth, rather than ¾” all at once. I then routered sides in the same manner. I also cut (on the table saw) a small chamfer on the bottom of the protruding section so it was not a sharp corner. I also cut the chamfer on the top of the baffle (shown below). This cut was at 30º and was done in on the table saw, against the rip fence. A vertical support piece was placed along the rip fence to provide a larger vertical surface for the baffle to run along. The support piece was temporarily held to the rip fence using double sided tape and removed after the cut as made. This cut need to also be ¾” deep to match the chamfer on the sides and is used to locate the front of the OB section when positioning it. This was very difficult to hold steady with such a large piece and perhaps a little dangerous. It did not turn out as well as I would have liked. If I had to do it over, I would make a sled jig of sorts that I could clamp the baffle to and slide the whole thing along the rip fence in one piece. This is what I would recommend for anyone trying to make a cut steeper than 45º. It would be much more effective and safer. You could also just do a 45º cut here also with the table saw or chamfer bit.

Next I clamped the baffle to the box and using the holes I had already drilled as a guide, drilled pilot holes for the threaded insets into the box braces. Removing the baffle, I now was able to drill the appropriate sized holes for the threaded inserts and install them.



The next step was to create the driver rebate and rear mount opening. The driver rebate was routered from the rear of the baffle. From the rear of the baffle, I routered just a one bit width slot, at the appropriate depth (leaving ½” between the rebate and the front of the baffle) that defined the outside of the rebate. Then I routered out the through hole. Using a ¾” roundover bit in a router table, the roundover for the front of the woofer hole was completed next. I recommend doing it in several passes of increasing depth. The round over had to be done before the rebate was completed so there was material left for the bearing to ride on. Once the roundover is complete, I went back and set the router depth to a depth of about 3/16” less than the depth of the ring I cut from the rear and routered out the excess of the baffle to make the rear driver rebate. The 3/16” difference provides a lip for the driver frame to set into the rebate and the shoulder provides a place for gasket to seal the driver. BTW, I removed the outer rubber mounting ring that comes with the TD12H for my application, hence the protruding lip and need for gasket.







I also had to drill the holes for the threaded bolts that hold the driver in place. To do this, I positioned driver in the rebate, making sure the hole positions lined up vertically and horizontally and the driver was centered. I used the driver frame holes themselves to start a shallow pilot hole with a hand drill, but finished them in the drill press to be sure they were 90º. I used a 1/8” bit for the pilot holes through to the front of the baffle. Shallow counterbores were drilled for the cap head screws so they were close to flush when installed, using the 1/8” pilot holes to center the forstner bit. This left about 3/8” material between the bottom of the counterbores and the driver. Larger through holes were drilled, again a little larger than the diameter of the cap head screw shaft, to allow for a little wood movement, etc.



The final step was to add the contrasting ¼” hickory strip along the back edge of the baffle. I used a dado blade in my table saw to cut ¾” wide, ¼” deep rabbet out of the hdf to act as a shelf for a shelf for the hickory strips. I stopped short of hickory base pieces along the bottom of the baffle. That leaves about 1” of HDF that has to be chiseled out so the ¼” deep hickory trim pieces intersect the full depth base hickory pieces. Then I cut the trim pieces (I had previously ripped) to fit, with mitered corners. The strips are then glued and clamped in place and were later sanded to ensure a flush match with the surrounding wood.







Some sanding of the baffle sides, bottom and top edges may be necessary for a more perfect flush fit with the box once the veneer has been added to the box. Other than final sanding and finishing, the bass bin baffles are basically complete at this point.

I'll add a step by step on the open baffle later.

[dlneubec]

Open Baffle Section:

The open baffle section has a lot of small steps and if not done in the correct sequence can cause difficulties. Of note is the fact that you have a sandwiched baffle made up of Lexan with hardwood sandwiched between the Lexan and the drivers. Since the roundovers for the rear mounted midrange and tweeter have to those sandwiched materials match exactly, it is critical that they be created with the sandwich together in one process. I used double sided tape to accomplish holding them together during almost the entire process.

Starting with the raw laminated baffle, I marked the center points for the drivers for use with a circle jig later in the process. I used these center marks to draw the baffle shape on the wood so I could tell where to stop the routering at the circular intersections. I created a little extra interest by adding a little shadow box-like detail to the hardwood baffle that added one extra complication. This was simply an extra ¼”wide x 1/8” depth shelf around the mid section at the edges of the baffle that faces the back of the Lexan. You can see this in the lines drawn on the wood. Here it is laid on the back of the Lexan baffle.



The routered circular shapes are all done first since they require a center hole for the circle jig. Here is a series of photos where I have used double side tape to hold the hardwood section of the baffle against an mdf backer piece for the edge routering.









Here I have positioned the reshaped baffle onto the Lexan and lined up the centerlines on the pieces and then stuck them together using double sided tape. They will be held in this position for the remainder of the construction, so ensure everything is perfectly aligned. The center holes that were measured and drilled into the hardwood are now completed through the Lexan baffle. On the face of the Lexan (or its protective covering, that is) I’ve drawn centerlines though the drivers center holes. These will later be used to help located the drivers mounting holes at a later step.



As with the woofer baffle, both of these drivers will be mounted from the rear, so a rebate needs to be created from the rear. This must be done after the driver through holes are made, However, since the full depth of the two sandwiched materials is needed for the roundover bits bearing to ride on when the roundovers are completed from the front side. Here is a series of photos that show the steps of creating the start of the rebate for the tweeter, the mid and tweeter through holes and then the roundover. The roundovers were done in numerous small increments in the Lexan, to ensure it would not grab. Also included is a shot of locating and creating the tweeter bolt holes before the roundover is done. This is done by using the tweeter faceplate and the registration lines I drew on the front of the baffle while visually lining up the through hole in the baffle with the center hole in the faceplate. The faceplate was again held in place using double sided tape, as shown. I did small pilot through holes for the tweeter mount and did the counterbores for the round headed hex head screws before the roundover was done.











After the mid and tweeter roundover were done (mid 5/8”, tweeter ¾” radius), next the mid driver rebate and mounting holes had to be completed. First I placed the mid driver font of the baffle and aligned the driver holes with the alignment marks I had drawn on and while holding it in place, flipped it over to visually align the driver in the center of the driver through hole. I had to flip it back and forth about one more time to get the driver mounting holes aligned and the driver itself centered in the through hole and then held it in place while I marked the mounting holes on the front and drilled pilot holes through to the rear. Then I used the same process to drill the counterbores and larger through holes I used before with the woofer and tweeter. I used a template to do the driver rebate after mounting the driver in place and using it as a guideline for aligning the template. The rebate depth was at a depth so the driver ended up 11/16” back from the baffle front.





The tweeter rebate was then routered out. I then had to drill some recesses for the terminals on the tweeter, which were done with a forstner bit, once the locations were marked. The tweeter was also rebated such that its depth is 11/16” from the face of the baffle.





You will notice that in the last photo, I have tried to polish the roundovers a bit. I used the synthetic flap wheel in a drill first and then followed that with a cotton polishing wheel in the drill. Without much effort they look pretty good, translucent, not clear, but maybe good enough without further effort.

I forgot to take photos of the construction of the support pieces for the back of the open baffle, but I will take some when I disassemble it all for the bass bin box veneering process, which will probably start next weekend. More to come then.

[---k---]

Very nice. Thanks for the detailed write up. I picked up a few ideas for my next project - whenever that gets kicked off.

[dian1511]

Great documentation and really professional looking work. I like the look of the curved circles after working them. Thanks for all your efforts.

Darren

[dlneubec]

Here is a little update. I got the veneer complete on one speaker and the hardwood slot port installed. I sanded it all down and put two quick coats of zinsers sealcoat on it. The crossover is still out of the box, with wires through the slot port. Here are a couple shots. Unfortunately, they are taken this evening after dark, so I had to use a flash. Really looking like a speaker now. I have not done any polishing on the roundovers on this baffle yet. I have yet to decide whether to do a high gloss or satin finish on the wood parts. What do you all think?

[Face]

Very nice.

IMO, I would consider a satin, it would look better if the glass and cabinet have a similar amount of sheen.

[Hdale85]

I really like the super gloss finish on any speaker.

[dlneubec]

Very nice.

IMO, I would consider a satin, it would look better if the glass and cabinet have a similar amount of sheen.

Ok, you have me confused here. Are you saying you would prefer satin or high gloss on the wood?

[MuaDibb]

Dan I think you have enough figure in that wood and veneer to warrant more of a gloss finish. Just my opinion tho, Tom.

[CupCak3]

You sir, are an artist!

[dlneubec]

A daytime pic with more natural looking colors:

[---k---]

Dan,
I don't think the pictures are doing you justice.

[CraigJ]

And how do they sound?

[dlneubec]

And how do they sound?

Very, very good. I believe they are my best work so far.

[ttan98]

Very good looking speakers, Excellent work.

What is your total approx. cost including:

1. drivers
2. x-over
3. cabinet
excluding labour, probably costs more than all the above. Itemised if possible?

Cheers.

[dlneubec]

Very good looking speakers, Excellent work.

What is your total approx. cost including:

1. drivers
2. x-over
3. cabinet
excluding labour, probably costs more than all the above. Itemised if possible?

Cheers.

I have a preliminary cost estimate for the pair(see below). The crossover has changed a bit since this was done, but it is still pretty close. I have this in a spreadsheet and will update it after any final tweaking. This does not include mdf for the box, probably 1 sheet at $22 or so, the hardwood for the baffles (cost me $104, IIRC) and the Lexan, which is currently about $66 plus shipping.

[JoshK]

Wow!

[cjd]

Not bad at all on the price!

Beautiful work as usual. Really makes me wish I had a proper workshop where I could let projects gather dust for much much longer periods...

[dlneubec]

Not bad at all on the price!

Beautiful work as usual. Really makes me wish I had a proper workshop where I could let projects gather dust for much much longer periods...

Thanks.

I hear you on the shop! One day I'd like to build my own dedicated workshop. My current "workshop" is half of my garage. It is not insulated, but I keep it reasonably comfortable this time of year with a 50,000 btu kerosene heater. The other half keeps the wifes car under roof while my car sits in the driveway (not fun this time if year). I have to pull her car out before I do any work, however. With no dedicated dust removal system, sawdust gets all over the car, tracked into the house, etc. :roll:

If I had a basemement, I'd have done a shop in it long ago.

[EdL]

Dan,

Where do you plan to place the led's which will illuminate the baffle? Bling! :B :rofl:

OK, just kidding.

Seriously, we heard these in the development stage @ diyLex and the sound will be hard to top. mid- range clarity with controlled directivity stand out in my memory.

Concerning the shop location: think twice before you put one in the basement, words from my grandfather.

[dlneubec]

Hi Ed,

You know I'm not afraid of a little Bling! :W

My wife has said these are her favorite so far, which is important to me, since they have to reside in our main living space.

Since I don't have a basement, I will have to settle for something else. Given the economy and the looks of my 401K after the last year or so, it will probably have to stay in my garage for the forseeable future!

BTW, I should have Paul's speaker this weekend to start on the crossover design. I'm looking forward to seeing what it looks like.

[JoshK]

My shop is in my basement. Its kind of a drag for the reasons that space keeps shrinking, wife complains of dust in her laundry area and dust gets upstairs sometimes. We do what we have to.

[thadman]

Those speakers are breathtaking!

[dlneubec]

I took a break to work on a crossover design for another project, but I'm back trying to wrap up the BaSSlines finish. I have decided to go high gloss throughout. Here is a little taste of what they will look like when completed. I hope to have the finish wrapped up in the next week or two and then will make any final crossover tweaks (if any) and publish the completed design. I used a small spare room we have upstairs to do the finishing in, since it is easier than doing out in the garage this time of year. I etched the logo on the Lexan with by hand with a dremel using vinyl stencils (that John over at AE speakers did for me, thanks John!) as a guideline.

[AJINFLA]

If AE has a showcase, these certainly belong there.
If they don't, maybe this would be a good reason to start one

cheers,

AJ

[dlneubec]

Thanks AJ!

[ttan98]

Dan,

Looks good, I wish I have your carpentry skill.

Can you please summarise the details of your design, esp., x-over, ie x-over freq. etc.

cheers.

[dlneubec]

I will post a summary, and/or maybe put it in the first post at the start of the thread when I have everything finalized. Crossover points are about 450 Hz and 2400 Hz. More on that later.

[dlneubec]

Here are a couple more:

[titch--]

Very nice Dan!

[JoshK]

These turned out wonderfully. They look fantastic as all your projects do!

I'm jealous.

When are you going to start on mine?

[Johnloudb]

Beautiful looking speakers you've built there Dan! You definitely have an artists touch. Can't wait to get you're sonic impressions on these.