Speedster TMM

[Beau]

Re: Speedster TMM

Beau,

Another option to consider is the Speedster Tower that I built and demo'ed at the Kentucky DIY event. It is Speedster MLTL which uses the original Speedster bookshelf crossover but repackages the drivers into a small floor standing speaker. The F3 cutoff and bass performance is akin to the TMM version. More data at:

http://techtalk.parts-express.com/showthread.php?240332-The-Speedster-Towers-A-MLTL-version-True-to-the-Originals

Jim

Jim,

Thank you. I try not to "blown sunshine" at people, but I have been VERY impressed with your designs.

Beau

[Jim Griffin]

Re: Speedster TMM

Beau,

Thanks for the comment but Paul deserves more credit for his basic design. I just designed the MLTL version to accommodate his bookshelf design.

Jim

[Beau]

Re: Speedster TMM

Understood.

The as-originally-designed Speedster changed my mind about what was possible wit small drivers.

[Squidspeak]

Re: Speedster TMM

My first build was also a huge strain to get the finish looking decent (and sadly, it never did). However, I have learned a lot of tricks over the years to getting a decent finish quicker.

For spray paint, the surface has to be in excellent shape. So if you have the time to use lots of bondo, it's worth it. Also, the surface needs to be primed and sealed VERY well, or the MDF will soak up spray paint like a sponge, and the finish can't even get a started. THe good news is, you've probably sealed the surface pretty well when you sanded down the hammered paint. So you can pretty much use whatever you like at this point.

Some people have gotten cool results using surfaces like Formica and Wilsonart. They make some pretty cool-looking stuff. I have tried it, but never could quite get the adhesion I wanted.

In the end, paper-backed veneer ends up being the most forgiving. The trickiest part is getting it to stick evenly. A bad glue job with weak corners is a disaster waiting to happen (imaging peeling off the entire finish of your speaker in one sheet). I have found the most surefire method to get veneer to stick is "cold press." Basically, spread an even coat of wood glue on both surfaces and clamp a hard, flat plate to it (ie: large sheets of MDF). Let it sit overnight, trim excess veneer, and continue on the other surfaces. Yes, it's time consuming, but worth it. There are so many nice-looking things to do with wood finishing. You can dye it, stain it, leave it natural. Then there's the clearcoat: wiping varnish is really easy (and relaxing, in my opinion), or you can get hardcore with a spray setup if you want a "guitar-quality" finish.

Another veneering option is peel and stick. Pressure sensitive veneers
are very easy to use,but like contact cement you get one chance to position it properly but
other than that it is by far the easiest method of applying veneer. Most veneer supply companies stock several species with peel and stick adhesives. Good luck,Happy Holidays

[nrg74]

Re: Speedster TMM

Quick update, the outside is done, I'm happy with it.
tomorrow I will screw in the x-over boards on the backwall.
I will use the 1inch thick dacron wool.
-- open to ideas-- I was thinking to staple each layer to ensure it stays in place at the top of the cabinet?

After that I will hold them closed with clamps to test listen and make sure all is well before the last big step of glueing it shut, again open to ideas on how to get an air tight seal between the front baffle and the box.

we are getting there! I also ordered some paperbacked veneer. Maybe for my next project!
Thanks everyone, I learned a lot, one of the joys of DIY.

[nrg74]

Re: Speedster TMM

I'm putting in the stuffing... I'm using the 1" bonded dacron. I have 10 layers to put in there.. I can't believe it: I have to cram it in. I may have to cut holes in the last 2 layers otherwise the drivers probably won't fit. Does this seem right?
Only the top 25inches have material. The photo is taken from the bottom.

[Jim Griffin]

Re: Speedster TMM

You should place it into the enclosure--not cram it in. If you cram it into the box you will essentially increase the density. What the designer intended and simulated is 0.75 lbs/cu.ft. .

[nrg74]

Re: Speedster TMM

Jim,

I appreciate your input, and I have a ton of respect for your designs. I am just a complete rookie, and apologize for my questions.

With the kit that I got the guidance is to layer a total of 10 layers of the dacron. However the enclosure only 9 inches deep, subtract from that the crossover board and the depth of the speaker magnets, etc. It would seem that 8 layers would be more appropriate.

Maybe I should direct the question to the folks that supplied the dacron and the cut-template.

Thanks for your help.

[Paul K.]

Re: Speedster TMM

I modeled this design for Paul C. and the required stuffing density is 1 lb/ft3 in the top 25" of the cabinet. Back in August, Mark Sayer emailed me because he knows I like to use his Dacron batting with its inherent density of 0.75 lb/ft3 in most TLs I design/build (for obvious reasons). When he asked me if he could supply the Dacron batting pre-cut in this kit, rather than using loose fill like Acousta Stuff or Polyfil, I told him he'd have to compress it some in order to get the required density. The total weight of stuffing required was ~10 ounces, and since Mark wanted to cut pieces 5" x 25" and stack them back to front, I estimated he'd need 11 pieces to equal a weight of ~10 ounces. So, you will need to compress the stuffing, and you will also need to cut some of it away around the woofer for clearance. I think you said there were 10 pieces of this size provided for each cabinet. Don't worry about that being 1 to few as the resulting stuffing density will be close enough.
Paul

Jim,

I appreciate your input, and I have a ton of respect for your designs. I am just a complete rookie, and apologize for my questions.

With the kit that I got the guidance is to layer a total of 10 layers of the dacron. However the enclosure only 9 inches deep, subtract from that the crossover board and the depth of the speaker magnets, etc. It would seem that 8 layers would be more appropriate.

Maybe I should direct the question to the folks that supplied the dacron and the cut-template.

Thanks for your help.

[nrg74]

Re: Speedster TMM

Paul K,

That makes sense now! Thanks for the quick reply.
I'm making lots of progress. I also realized I needed to cut holes for the drivers. I attached another photo. Unfortunately in the photo you can't see the 'metalized' finish of the front baffle.

Any last advice before I close up the box?

enjoy, this is your work as much as mine!!

[Paul K.]

Re: Speedster TMM

I assume the assembled crossovers are already installed and that you checked their wiring to make sure they are correctly assembled and all solder connections are good? Have you confirmed you have continuity to the crossover input as well as crossover outputs to drivers? If so, it would seem you're ready to close them up and start enjoying them.

Paul K,

That makes sense now! Thanks for the quick reply.
I'm making lots of progress. I also realized I needed to cut holes for the drivers. I attached another photo. Unfortunately in the photo you can't see the 'metalized' finish of the front baffle.

Any last advice before I close up the box?

enjoy, this is your work as much as mine!!
[ATTACH=CONFIG]43159[/ATTACH]

[nrg74]

Re: Speedster TMM

I have one Speedster TMM finished! It sounds good in mono, but the true test is in Stereo. I will do a side by side listening test with my Infinity Primus250 floor standers as well as the Frugal Horn.
I attached a photo of my basement setup. Next I need to work more on the room to create better acoustics.

Thank you all very much for your help and support.



I will update as I finish the 2nd speaker and allow some time for listening.

[nrg74]

Re: Speedster TMM

I finished both speakers. They are both on a diet of my class D amp and playing mp3 files through the ipod shuffle. I figure on giving them about 100 hours of easy playing.
First impression is that the bass is very strong! If that is because of the MLTL then I am a believer! Also the highs are already very clear.
So far so good but there is more to come.

[nrg74]

Re: Speedster TMM

Wishing everyone a happy, healthy and successful New Year.

[bill poster]

Re: Speedster TMM

nice project, those little tang bands have a small rise in the bass so two together must be quite ample!