Dallas II BLH Plan

mightym · « **Reply #20 on:** 18 Aug 2010, 11:30 pm »

Quote from: andrewbee on 18 Aug 2010, 09:26 pm

To make all internal pieces the same width use the sawboard and cut them ~ 3/16" oversize and then set your TS and run them through... all will be the same width.
The ~3/16" should take care of the blade kerf and not waste much wood.

Thanks andrewbee, excellent idea. If you saw my cruddy little table top table saw you'd know why I use the saw board. Even if I could find someone to catch the boards, I can still get a more true cut with the saw board.

Measure twice, cut once My Mantra. OMMMM...

John

I had an epiphany last night, (I can't say it came to me in a dream, 'cause I thought of it before I went to sleep) I'll make a "Gauge Block" to set the saw board with. Then if I carefully set up the cut, it should be repeatable infinitely.

mightym · « **Reply #21 on:** 23 Aug 2010, 01:07 am »

The only problem with using a gauge block, isn't that it's infinitly repeatable, it's that when you make the gauge block the wrong size because you forgot to carry the one when you added the distance from the saw edge to the kerf, and the length you want to cut off, Everything you cut with it is wrong.....

Let me start again. I worked all weekend on the Dallas II's. I took pictures and put them in the gallery ( the ones that weren't blurry).

Long and short of it is this: I added 3 13/16th" ( the distance from saw shoe edge to the far side of the Kerf ) to 17 11/16th", and forgot to carry the 1, making a gauge block that rendered 16 11/16th" cuts. I beboped along not realizing my mistake until I'd cut out the sides, and bottom of the cabinets....an inch short...GaaHHHH.

Not to worry, I found a piece of Pine, and glued it to the short pieces ( in the back where it won't show ). I only made 2 gauge blocks, the other was perfect, and was used to cut out everything that goes between the cabinet sides, it worked out very well.

The cabinets are all cut out, everything has been given it's first rough sanding, the baffle's are machined, everything is ready to go 3D, tomorrow, and what ever I can squeak out in the shop next week. This will be another new adventure, I've never assembled a cabinet with glue and brads before, usually I glue and clamp. I hope the nailer speeds up the process.

I hope all 3 of you watching are as excited as I am.....

Here's a gratuitous pic.

Stay tuned.....
John

rjbond3rd · « **Reply #22 on:** 23 Aug 2010, 03:46 am »

Hey congratulations on getting everything cut.

Yowie, this is a big project, and you are almost there!

mightym · « **Reply #23 on:** 23 Aug 2010, 11:32 am »

Thanks Robert.

The only thing is, I know how far along I'm not...

Next step Glue slingin', brad drivin', maybe some cussin' ( probably ).

But I've got to sweep up, and pull the drop cloth off the shop system first, so I can keep breaking in the drivers, and have some tunes to work to.

John

mightym · « **Reply #24 on:** 25 Aug 2010, 03:09 am »

We've gone 3D!

A little bit of progress tonight and last night.

Robert your question about the panels possibly needing to be " evened out" was spot on. Even though I was very careful in my layout, I am having a few of my pre-cut pieces vary as much as a 32nd of and inch in width. A few parts came out less than square too. So far everything is lining up on the baffle nice and even. I forsee some time spent with a straight edge, and my belt sander before the final sides are attached. So far it's not looking too bad. I am using PU glue, so small gaps are not a problem.

5 more pics in the gallery ( yeah, 5 more of his crappy phone cam shaky hand pictures.....).

John

rjbond3rd · « **Reply #25 on:** 25 Aug 2010, 06:52 pm »

Looking sharp! You must be so psyched.

Yeah, I didn't phrase it well in my original post, but I was imagining (due to the lack of perfect 90-degree angles) that you might want to sand down the sides to get things perfectly true.

What I saw others do is to put sand paper on something known to be perfectly flat, and just go back and forth. Maybe putting some colored pencil on the side edges would help? Once the color is gone, it's flat?

(That's what they do at the dentist - they use some kind of carbon paper, you bite on it, then they sand down the high spots.)

mightym · « **Reply #26 on:** 26 Aug 2010, 12:15 am »

Thanks Robert. I am Psycheded.

The bits that are not lining up are usually not off by more than a 32nd". I have a couple of different straight edges I can use to check the horn before I button them up. The boxes are too big, and heavy to do like you suggested. I'll use the straightedge in combination with a belt sander to level everything up. The PU glue I use will also fill small gaps.

I never got the call to go to work today, sooo, I've been glue slinging, brad driving, and digging the tunes as I break in the drivers.

I assembled the bit that goes behind the driver, took pictures, then glued them into the cabinets. All that is left to put into the cabinets, is the part that attaches to the bottom of the baffle, and splits the last 2/3rds of the horn path ( first bend outside to second bend inside ). I'll take more pictures after I finish diner, I expect to post again later tonight, I'm very pleased at my progress today.

John

PDR · « **Reply #27 on:** 26 Aug 2010, 12:19 am »

Looking forward to the new pics......

mightym · « **Reply #28 on:** 26 Aug 2010, 02:31 am »

More crappy phone cam pics posted to the gallery. Here's a tease:

I got a little more accomplished on one of the horns after dinner, but it's not ready for photos yet. This part I decided to clamp, and not brad nail. The last board in the mouth of the horn is in ( board directly under the baffle ), and so is the long divider terminating in the second bend. Next thing to do is install the outer portion of the first bend/ flare to the horn mouth. I didn't like the way the full size drawing came out here, so I'm re-engineering it to smooth the outside of the bend slightly. Instead of being made up of 3 pieces, I'm using 4 ( Strike that, it's now 5 I wasn't happy with how the expansion arcs were being followed, now I am). It still follows the radius indicated on the plan.

Stay tuned....
John

mightym · « **Reply #29 on:** 28 Aug 2010, 04:59 am »

I got home early today, after working 24 of the last 48 hours, did I take a nap?... No!

Did I check my E-Mail ( well... Yes)

Hey, I went out to the shop and worked on the project too....

Looks better in person.

Should have both cabinets to this point tomorrow...
John

Mariusz · « **Reply #30 on:** 28 Aug 2010, 05:08 am »

Get some rest John......

Good looking cabs.

PDR · « **Reply #31 on:** 28 Aug 2010, 05:21 am »

Cool.....I have done a loy of DIY projects in the last few yrs.....I know exactly how it feels....

Looking VERY nice!!

mightym · « **Reply #32 on:** 28 Aug 2010, 11:40 am »

Thank you gentlemen, Having the feedback is helping to keep me motivated. I'm going to need that when I go into " finishing mode".

Every hour I work on these( except when making sawdust ), the drivers are breaking in, sounding smoother, making more bass ( on an OB!, a low Q driver! ). I'm excited to get these together so I can see how they sound.

Thanks again,
John

mightym · « **Reply #33 on:** 29 Aug 2010, 02:17 am »

Well, I piddled along today, all I got done was the last of the bits in the first bend on both cabs.

I'm going to seal the inside up with a couple of coats of Poly/spit coat. I haven't got the foam to fill the top voids with yet (I'm using kitty litter in the bottom void only-These things have gotten heavy-the weight down low will help stabilize them from Kamikazi Kitty's), I can take care of that this week. Need to drill the wire holes, and run a bead of sealant over the seams inside the horn before I button them up. Then on to making the outsides look purty ( veneer ), and smoothing /painting the insides where they'll show when the grill is off.

Mr. Clarke recommends putting felt on the outside of the bends to help ameliorate the high freq's, and lining the chamber behind the driver too. I'll need to do this before button-up. Have T-Nuts installed already so driver tweaking can wait till after I get a chance to hear them in system, then I can decide what/how much driver tweaking to do.

It's coming along.
John

rjbond3rd · « **Reply #34 on:** 29 Aug 2010, 03:12 pm »

Those are beautiful. And now I know that this is well beyond my building skills

Teflon · « **Reply #35 on:** 30 Aug 2010, 04:34 pm »

Looks great. I've just started looking at horns for a possible project and I like this one already.

mightym · « **Reply #36 on:** 2 Sep 2010, 02:08 am »

Short update,

First, Robert don't sell yourself short, my woodworking skills are limited at best, I've only built 3 sets of speakers in my life, and these are the first BLH's I've attempted. Look at the incept date on this thread, you will notice that I started this journey about a year ago, I've had lots of time to think about how I wanted to do this with my limited tools.

Thanks Teflon, I always like encouragement, do you use the same avatar on DIYAudio? ( Big'un?) I'm going to do the Beta build thing on the FH3's when I get this build finished in a few weeks.

Just a small amount of progress to report:

The insides have been sealed with 2 spit coats of poly. The upper voids have been foamed. Tomorrow I should be able to drill the wire holes, and sand the surfaces fair for the glueing, line the bends, and pop the other side on.

Then the finishing fun can begin in earnest. I'm determined to complete the cabinets before ever installing the drivers. I do not want to look at any raw wood in my LR....I built a pair of Recession Buster series 2 from Madisound last year, in a Tapered TL cabinet. They sound very good for no more than I have invested in them, but they still don't have any finish on them

( too busy listening to them I guess ).

John

planet10 · « **Reply #37 on:** 2 Sep 2010, 06:19 am »

Quote from: mightym on 2 Sep 2010, 02:08 am

They sound very good for no more than I have invested in them, but they still don't have any finish on them ( too busy listening to them I guess ).

It will be easier once you have multiple speakers.

dave

Teflon · « **Reply #38 on:** 2 Sep 2010, 11:50 pm »

Quote from: mightym on 2 Sep 2010, 02:08 am

Thanks Teflon, I always like encouragement, do you use the same avatar on DIYAudio? ( Big'un?)

Hi John,

Yes, this is Bigun! I joined here a couple of years ago or more, although you'll find I haven't been active very much. I am in learning mode - horn speakers - fascinating.

mightym · « **Reply #39 on:** 3 Sep 2010, 10:32 am »

I'm learning too...

I've been breaking the Fostex FE 206E's in on an OB I whipped up out of some material I had on hand. They have gotten a lot smoother as they wore in, I still notice that when I give the loud knob a little twist that they can get a little spitty on top. They are un-molested, and have somewhere around 70 hrs on them now ( Guessing, I didn't keep track ) maybe more.

I want to get the horns finished so I can see what a little loading on the back of the cone will do to the sound. At low levels, other than the lack of low bass, they sound very nice on the OB. When toed in a bit in front of the listener, the rising response of the driver isn't so noticeable, and the sound stage is addicting.

These are my first foray into the " Single Driver " world, and I'm having fun.

John