The BaSSlines (was High Sensitivity Design)

[dlneubec]

David,

Yes, you are correct. I lost my place across columns and posted the 12"x24" price. The 1/2"x24"x24" price is ~$71.

[David_D]

I think we may have a winner on looks from one of these.

Both of those are gorgeous. I am partial to the second. Just watch how the grains will raise differently on the different species. I foresee lots of sanding in your future. Can't wait to see pics. :T
BTW; I like your logo. Maybe an aluminum or stainless plate with the characters Waterjet cut out of the center on you can see the wood grain behind. Just an idea.

[Saurav]

If I do sloped, then I have the option to do one continous baffle, with no need for rear bracing of the open baffle mid panel.

You might want to wait on that until you build it. My last speakers had a single panel for the baffle which included the front of the sealed woofer cabinet and the upper OB portion. The upper panel vibrated quite a bit from the woofer. I never did anything about it, but I'd suspect you wouldn't be happy with that.

[dlneubec]

You might want to wait on that until you build it. My last speakers had a single panel for the baffle which included the front of the sealed woofer cabinet and the upper OB portion. The upper panel vibrated quite a bit from the woofer. I never did anything about it, but I'd suspect you wouldn't be happy with that.

Yeah, you're right. After I posted that I remembered that was one of the reasons I didn't follow the Salk design with a single straight baffle. I wanted to separate them to try and attenuate vibrations in the open baffle panel from the woofer. My plan was to connect the support legs for the open baffle panel to the top of the bass bin box with some rubber washers and leave a small gap at the bottom for something like a strip of adhesive-back vinyl dampening sheet between the mid/tweet and the bass bin baffles.

[dlneubec]

Both of those are gorgeous. I am partial to the second. Just watch how the grains will raise differently on the different species. I foresee lots of sanding in your future. Can't wait to see pics. :T
BTW; I like your logo. Maybe an aluminum or stainless plate with the characters Waterjet cut out of the center on you can see the wood grain behind. Just an idea.

Ok, you lost me with the last sentence. I cut the logo's by hand from vinyl vibration dampening sheets, which was a bit tedious. I'd love to know another way to do it, that is not prohibitively expensive.

[cjd]

Yeah, you actually did exactly as I would have, cutting the center color piece so it doesn't actually go above the tweeter. And I didn't even say that. Could add a third speces there too possibly.

If you want to make the top part completely stand-alone, that center rib would be a natural to extend back and be a rear "leg" for this so the entire upper mid-tweet baffle just rests on the bass bin.

C

[cjd]

Ok, you lost me with the last sentence. I cut the logo's by hand from vinyl vibration dampening sheets, which was a bit tedious. I'd love to know another way to do it, that is not prohibitively expensive.

Have a vinyl sign shop whip up a batch for you. Give 'em a computer file (they'll tell you what formats) and it shouldn't be too bad. Can probably get different colors, even metallics.

C

[David_D]

Ok, you lost me with the last sentence. I cut the logo's by hand from vinyl vibration dampening sheets, which was a bit tedious. I'd love to know another way to do it, that is not prohibitively expensive.

Sorry, I didn't realize you already had a method.

Have a vinyl sign shop whip up a batch for you. Give 'em a computer file (they'll tell you what formats) and it shouldn't be too bad. Can probably get different colors, even metallics

Looks like that's the ticket.

[dlneubec]

C

We are thinking alike here. The plan is to have two horizontal legs, parallel to each other, that are glued into the lamination (I guess that would be a lap joint?) going back to support the whole baffle, so it can all sit on the bass bin. Depending on vibration, they may have to be bolted down, just to maintain position. The legs would be connect by dowels, aluminum rods or similar toward the back end. I wanted two legs, 3/4" wide x 1-1/2" tall (1-1/2"- 2-1/4" apart) or so, so I can hide the binding posts in between them. I will also router a channel in two of the laminated vertical pieces, to make about a 3/8" square conduit, so I can run the driver cables up through the baffle. I want the wires to be hidden, unless you go looking for them. I did this with my NaO Mini's and liked the "wireless" look.

I had thought about a vinyl sign shop, but just assumed that they didn't do things that small. I'll contact the one shop we used for some of our company logo/signage. Thanks for the idea.

[dlneubec]

Sorry, I didn't realize you already had a method.




Looks like that's the ticket.

The ones I made by hand were for these. I created the logo tiff file, printed it, glued it to the vinyl an then cut it by hand and superglued it on the speaker. I'd rather find an easier way to do it, however.

[cjd]

You could also have them cut stencil versions on a low-tack vinyl and use it as a mask to apply a die... *should* be affordable enough to make worth considering...

[Bill Schneider]

Or use the stencil to mask the polycarbonate to give it an etched crystal look.

With a thin enough stencil and steel wool, you might be able to do it by hand without sandblasting or using etchants.

Experiment with some masking tape on a piece of scrap.

[Saurav]

I wanted to separate them to try and attenuate vibrations in the open baffle panel from the woofer. My plan was to connect the support legs for the open baffle panel to the top of the bass bin box with some rubber washers and leave a small gap at the bottom for something like a strip of adhesive-back vinyl dampening sheet between the mid/tweet and the bass bin baffles.

Sounds like a plan. You basically need something that'll damp vibrations in the frequency range that the woofer will be handling, and I have no idea what the right materials would be for that. Materials used for speaker enclosure damping would be a logical choice, as well as (potentially) sorbothane or other materials used in audio isolation products. Though there's so much mumbo-jumbo and so little physics in that industry that I find it hard to decide who to trust.

Following the 'isolation products' line of thought, another option might be a free-standing upper baffle, with cones or some other type of 'feet', maybe with dimpled plates or whatever on top of the woofer enclosure to ensure repeatable placement. Hiding the wires might get trickier with this approach.

Fundamentally, you're trying to prevent a certain frequency range of vibrations from moving in one direction through whatever interface you establish. And since the vibrations are coming direct from the woofer, they're probably stronger than what the average CD player feet (and related products) need to handle. I'm sure every product out there will say that it's the right solution for the problem, but hopefully with some research you can narrow down on what is actually likely to work. Maybe your idea of using cabinet damping materials is the best approach after all.

[dlneubec]

Following the 'isolation products' line of thought, another option might be a free-standing upper baffle, with cones or some other type of 'feet', maybe with dimpled plates or whatever on top of the woofer enclosure to ensure repeatable placement.

That's how I did it with my NaO mini's which set on top of 12" subs and in the HOSS project (pictured above). I recessed rubber footpads for chair legs into counerbores in the bass bin top. They were recessed enough and just the right size for the dimpled spike feet to fit into. Then I used small, 5/8" tall spikes on the bottom of the MTM section. It worked very well and looks great as well. However, for this one, I'd like the option to have it a little more secured, especially with the prospect of using the clear baffle.

[dlneubec]

In order to have the thin center piece, I had to shift the lamintes from my original design, which had a laminate edge cetered. This makes the whole center section a 3/4" narrowe or 1-1/2" wider. I chose 3/4" narrower. Then I added the name and/or logo on the polycarbonate. Hopefully, this can be done with a template, as CJD suggested. I'll have to check on the cost for a template, of course.

What do you guys think?

[Saurav]

How does it looks with dln on top (like your first picture) and BaSSlines on the bottom, below the woofer?

I like dln on top better than BaSSlines on top.

[dlneubec]

I can do that, give me a minute!

[dlneubec]

Something like this?

[Saurav]

That looks pretty good to me. I'd visualized the lower text in black, on the front baffle above the base... basically, where you had your logo in the earlier pictures. Black text might look nice under the black woofer. But your version looks more understated, which I also like.

Disclaimer - I am known to have very little eye for design

[Hdale85]

I liked the black logo at the bottom better.



This would be my favorite with the black logo placed at the bottom like in the first pics.

[Bill Schneider]

I'd K.I.S.S. with logos and such. You don't want it to look too corporate.

If you're using a stencil to give the polycarbonate the etched look using a hand abraded technique, you probably want a thicker stroke to the letterforms. Thin strokes on glyphs can be problematic. Of course, experimentation with scrap polycarbonate will tell you the limits.

One thing I noticed with the BaSSlines logo is how the capital S's suggest treble clefs. I found that to be a clever touch, without it going into "syrupy excess" by actually using a treble clef character as shown below.

[John_E_Janowitz]

hi Dan,

regarding your logos, I have access to a vinyl cutter. If you get me a logo in some kind of vector format I can cut a few and send to you. If you're going with the black logo on there one thing you can do is do it in black vinyl and bury the vinyl under the clear coat. If you need stencils for etching on the polycarbonate that is easy too. For our dustcap logos on the AV series we're using the vinyl stencils now. We spray the clear coat on the dustcaps, then come back and etch with 120grit in the sand blast cabinet. It's nice because we can do custom logos for customers on the alum cones too.

John

[---k---]

Wow. Very cool. As always, "Not what you know, but who you know."

[dlneubec]

hi Dan,

regarding your logos, I have access to a vinyl cutter. If you get me a logo in some kind of vector format I can cut a few and send to you. If you're going with the black logo on there one thing you can do is do it in black vinyl and bury the vinyl under the clear coat. If you need stencils for etching on the polycarbonate that is easy too. For our dustcap logos on the AV series we're using the vinyl stencils now. We spray the clear coat on the dustcaps, then come back and etch with 120grit in the sand blast cabinet. It's nice because we can do custom logos for customers on the alum cones too.

John

Thanks, John.

I'll see what I can come up with. I have it in a .tif file as of now, but it did come originally from my cad system, if I still have it that way. If I do, let me look at what formats I can output the file.

I'll get back with you. Hopefully we can work something out! :T

[ttan98]

Hi,

Reading your recent posts, you did not mention any change in your tweeter choice, I assume you are still using the Morel tweeter MDT33, I found the Madisound no longer sells them?

Any thoughts.

[dlneubec]

ttan98,

No, I was never going to use the Morel. I'm going to try the Peerless HDS.

[dlneubec]

hi Dan,

regarding your logos, I have access to a vinyl cutter. If you get me a logo in some kind of vector format I can cut a few and send to you. If you're going with the black logo on there one thing you can do is do it in black vinyl and bury the vinyl under the clear coat. If you need stencils for etching on the polycarbonate that is easy too. For our dustcap logos on the AV series we're using the vinyl stencils now. We spray the clear coat on the dustcaps, then come back and etch with 120grit in the sand blast cabinet. It's nice because we can do custom logos for customers on the alum cones too.

John

John,

Can you help me with what file formats you can accept for the graphics? I can give you an Autocad .dwg, .pdf, .tif, .eps, or possibly a vector plot file.
Would any of these work?

I would like to look into getting some black vinyl logos made and perhaps some stencils for testing on the polycarbonate. I would probably have to do the etching by hand with sandpaper, steel wool or something like that. I don't have any sandblasting capability.

[cjd]

eps *maybe* if it's the right type. I'd guess illustrator or freehand formats for sure... not pdf or tif i'm sure...

[ttan98]

ttan98,

No, I was never going to use the Morel. I'm going to try the Peerless HDS.

Hi,

Peeless HDS you are using has SPL about 91-2db, so you are losing some overall efficiency.

[dlneubec]

Hi,

Peeless HDS you are using has SPL about 91-2db, so you are losing some overall efficiency.

It is rated at 93db, (see published graph below) which is the max I was expecting for this system. I have yet to measure it to confirm. The Lambda TD12H is actually the least sensitive driver in the system at about 92db, but I can push it to about 110db with 100w and it will not even be breaking a sweat. I will be more than happy, if i can end up at 91-92db overall.

[Saurav]

The Lambda TD12H is actually the least sensitive driver in the system at about 92db, but I can push it to about 110db with 100w and it will not even be breaking a sweat.

Right. And your midrange can handle the same SPL levels at low distortion because it'll be well within its Xmax limits at those levels. So you need to make sure your tweeter isn't the SPL-distortion limiter, or at least, isn't too far below what the other drivers can do.

I know you know this, but I thought I'd point it out anyway After living with (albeit, poorly implemented) ribbons for several years, I'm really enjoying the dynamics of a good compression tweeter/waveguide.

[dlneubec]

Yes, I'm well aware of the limitations of dome tweeters. I have seen the Peerless used in some well respected systems, like this one for instance:
Elsinore

I believe this has a pretty high sensitivity and has been reported to play comfortably at 110db at the listening position. IIRC, it uses a much lower crossover than I'm anticipating, but he uses a flat delay type of configuration that is first order initially and then drops like a rock. I will also be testing the HDS mounted in a 1/2" deep waveguide, which could supply some low end boost centered around 3khz, which when equalized with the crossover, should provide more headroom, if it tests out well in his instance.

Here's a comment about the HDS in that thread by the designer of the Elsinore that is of note:

"Re Tweeter: Sorry, but I just love the new Peerless HDS 810921. Not only is it as good as tweeters several times the price but also they have one huge advantage: They are 8 Ohm. Most of its more expensive competitors are 4 Ohm (often really 3 Ohm like Vifa XT25). In speakers with higher sensitivities and using 1st order, the negative phase angle combined with Low Z (and no attenuation to keep sensitivity high) is really troublesome. I had this problem with the Mark 1 Elsinore and it was much easier to deal with when I went over to the HDS. Not to mention the HDS also sounds better, it is very versatile, and, to me this is important, the higher Z means the voice coil runs cooler - the dynamic compression is audibly very low. yes, there are other tweeters that I like but the HDS still comes up trump even if I wanted to spend more. Now if the new SS D30 (D3004/660000) was 8 Ohm - that would really tempt me. An 8 Ohm Seas Millennium too. But alas..."

He also confirms that the HDS has a sensitivity of 93db. At this point, I'm not to worried about it handling what it is asked to.

[Saurav]

Sounds like you've got it covered.

[dlneubec]

I made some small changes to the design and have started cutting mdf. I have cut the raw pieces for the mdf bass bins, but have to cut some rabit joints and all of the slots for the ribbed box construction. I will try to take lots of photo's to document the construction as I go along. For initial testing, I'm making the bass bin baffle and the open baffle section out of mdf. This is because I want to test the concept of rear mounting all the drivers, inset 1/2" with a 1/2" roundover.

For the tweeter, this will function as a shallow 1/2" waveguide. I followed Zaph's concept for this, proposed for an easy way to mount the Vifa D2NC55, on my Duo project and it worked exactly as he predicted, providing a 3db or so boost centered about 3khz. When equalized in the crossover, it has the potential to drop distortion levels even further and allow it to play at a higher spl without strain at the low end. It also, sets the tweeter VC back another 1/2", getting it in closer alignment with the woofer and midrange. I will test this with the Peerless HDS tweeter. If it tests out well, then I can mount the tweeter behind the Lexan baffle face, cut the appropriate diameter hole and do a roundover on the Lexan. Of course, I will have to test that on the Lexan first as well. :E

For the mid it will not really provide any real benefit. If it was a wood baffle, the rear mount would allow you to avoid having to router that odd shaped hole, but for the Lexan, you will still see the whole flange, so there is little advantage. Alternatively, if I want to mount the mid flush, it will take more work to extend the mid 1/2" forward to make it flush with the Lexan. In that sense, a rear mount, 1/2" deep, with 1/2" roundover may still be easier to accoplish. Of course, I will not do this mount if it has a detrimental effect on the FR of the any of these drivers in the passband.

For the TD12H, I like the idea of rear mounting because it visually plays down the mass of the driver, which is very dominant in this design. It will mean, however, that I have to make the front baffle removable, which is not a big deal and typical of most of my designs. I like to have full access to the inside of my box in case I decide to make changes in the future, like re-using the box for a different design with a different driver and baffle configuration. To rear mount the woofer also means it has to be lowered about 4", so it will fit into the box when mounted from behind and under the chamfers on the edges. This probably has the benefit of a bit more boundary reinforcement from the floor, but it separates the mid and woofer a bit more as a trade off. The temporary MDF baffle will allow me to test this configuration before I have to cut holes in the laminated version, which I obviously want to get right the first time! Below is what it would look like with a rear mounted woofer, sitting 4" lower. You can see the actual size of the woofer frame under the baffle in this drawing.

I also have to come up with a good way to attach the Lexan to the laminated wood support behind it. I may have to drill a few holes through the Lexan and countersink for some flat head screws, but I kind of hate to do that. If the drivers are mounted behind the Lexan, I have to keep it removable, in case a driver ever had to be replaced. Speaking of Lexan, I found a source that I can get a 1/2" x 24" x 24" sheet for $75 shipped. It should be here in the next couple days. I can't make any mistakes, however, since I need to get two tapered 11.875"-7" wide by 18.75" baffles out of it. It should leave a small amount for testing roundovers, logo etching, etc.

Any thoughts?

[David_D]

Hi Dan,
As far as the Lexan goes, I thought would do it, exactly like your picture suggests. Couterbore the Lexan for the driver flanges and use the driver screws to sandwich the lexan to the backer.

[augerpro]

Looks like a solid design Dan. Sometime back I had been looking at acrylic also for my open baffle. I saved the links on my work computer, I'll try to send them to you. Prices were pretty good. I think the companies were all the first handful of results when I did a google search for acrylic sheets, so they may be the same as the one you found.

[dlneubec]

Hi Brandon,

Thanks, but too late. :W I did the same thing you did and Googled it. I found Acrylic sheets could be had for about 1/2 the cost of polycarbonate (Lexan).

However, evryone I have talked to with any experience with these plastics, strongly recommended the polycarbonate over the acrylic. It is my understanding that polycarbonate is considerably easier to work with in terms of machining, etc. That's why I decided to go with the Lexan (orderd it yesterday).

Polycarbonate

[augerpro]

Ah, good info Dan, thanks. What were the reasons for the Lexan being easier to work with? I've only used really thin stuff-not sure if was lexan or acrylic-and it was a indeed a pain to work with. Shattered really easy when you tried to drill it and gummed up bad when you sanded the edge.

[Hdale85]

I've also heard that polycarbonate doesn't scratch as easily as acrylic.

[dlneubec]

Brandon,

IIRC, they said it had much less problems with the issues you mention when compared to acrylic.

After I cut it to size, (I'll try a table saw, maybe with a plastics blade) I'm assuming I will use only tools that can have variable speeds, like a drill press, router, etc. Slower speeds are supposed to help with the heating up and melting of the edges. I've also been told you can get a pretty smooth edge by very carefully heating with a heat gun, but you have to heat it until it first starts to smooth, because if you heat too long, it can quickly bubble. I will certainly have to expriment a bunch with that. I could always leave the machining raw or hand sanded, however, which would give it a different look, highlighting the edges.

[cjd]

if you're melting your plastic, you're working to hard/fast (and generating too much heat). Polycarbonate is definitely much better to work with. Shattering too, probably trying to move too fast or using a dull bit. No guarantee here, but that's my experience.

You can get plastic buffing equipment - wheels, compound. I'd use this, not heat. If I remember right, it works like metal - wet-sand to 600 or 1200 grit, then 2 or 3 levels of buff compound. Make sure you sand with a block. For perfect results, sand with a shaped block. Buff wheels for plastic can probably be chucked in a drill.

[David_D]

Polycarb has a much higher melting point than acrylic. It is also not nearly as brittle. Typical wood machining speeds are common. Work with slightly lower feed rates but you can treat it similar to a hardwood. I have routed holes & recesses easily with jasper jig & router. The only thing i did a little differently was countersink screws into all pieces to a watse piece of MDF or whatever as so the parts won't walk around when I broke though & lost the center.
Acrylic is famous for splintering, cracking, crazing. Polycarb is famous for making bulletproof panels.

[Dennis H]

Dan, check the polycarb when you get it to make sure it's flat enough for a see-through application. I bought some once to use for some skylights and didn't peel the paper off until after I had cut it up and I was installing it. It was so 'wavy' that the image distortion was unacceptable, even looking at trees and clouds. I ended up tossing it and replacing it with tempered glass. Ouch $$.

[dlneubec]

Dan, check the polycarb when you get it to make sure it's flat enough for a see-through application. I bought some once to use for some skylights and didn't peel the paper off until after I had cut it up and I was installing it. It was so 'wavy' that the image distortion was unacceptable, even looking at trees and clouds. I ended up tossing it and replacing it with tempered glass. Ouch $$.

Thanks for the heads up, Dennis. I'll keep my fingers crossed and hope for the best. Otherwise...... :rant:

[dlneubec]

Here are some construction photos: