I have taken the 1st step in assembling my 15 cu.ft. enclosures. I have been waiting for this for 30 years or so.
Marshall.
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I have taken the 1st step in assembling my 15 cu.ft. enclosures. I have been waiting for this for 30 years or so.
Marshall.
These the ones we discussed a year ago?
GM
GM, surely the ones. Many thanks for your input. Could do with further advice as things progress.
Cheers, Marshall.
The photo shows the clamping of 2 glued hardwood 2x1s which will give good screw bite for the removeable front panels. Fixed panels will be glued to 2x1 pine cleats.
Looking good!
Some years ago, I had a very large indoor area paved with natural slate tiles on a concrete slab. The adhesive used was rubber loaded to provide load spread and noise damping. If this type of adhesive will adhere to wood products it may work in constrained layer damping applications. I will experiment.
Cheers, Marshall.
You're welcome! You know where to find me...... ;)Quote:
Originally Posted by mah
GM
I am considering supporting the 15 cu.ft. cabinet on rubber tyred wheels at the rear and short solid legs at the front. Bottom panel X-braced. Timber floor on bearers on concrete stumps. Spikes don't appeal to me. Is this an OK arrangement?
Cheers, Marshall.
Same basic flooring construction as mine except concrete columns are assembled with concrete blocks.
I guess it depends on the tire's physical properties, though whatever it is should in theory be matched at the front. FWIW, my ~20 ft^3 cabs have rigid, high durometer rubber casters at the bottom rear with handles higher up for some ~back friendly mobility even up/down steps with a helper, so only contact the floor if tilted back a bit. The bottom has a thin sheet of cork like used to line tool chest drawers to allow them to be slid around on the floor for minor position adjustments or move them out of the corners enough to gain access to the handles.
GM
I have some 3 inch fibreglass/rockwool type insulation. Is this too thick to use in a large enclosure?
Marshall.
Quote:
Originally Posted by mah
Much too thick, 1 or max 1,5 inch is perfect.
I used 1 inch wool felted in my A7 cabinet.Quote:
Originally Posted by mah
Wayne
Thanks, guys,for you input.
Marshall.
Ping GM,
I am about to mount the 2"x4" braces to the enclosure panels.
I have some construction adhesive. Would you use the adhesive as a contact adhesive or in a glue and clamp(screws) method? The former is obviously easier.
Marshall.
If you mean this type of adhesive I used for most of my active building 'career', then if it doesn't shift or fall off from its own weight I don't bother with any fasteners or clamps, though if it were a prosound or other physically abusive app I'd at least add a screw or two as 'clamps' to ensure the wood around the bond breaks first: StickWithPL - Sealants, Adhesives Products Page
Since then though, this has come out, so I'm wondering if it might be an even better choice and plan to try it if/when I get to build something out of wood: StickWithPL - Sealants, Adhesives Products Page
GM
Sides done. Backs in progress.
Also a pic of some material I will use for damping the panels, if necessary.
This is literally a kitchen based assembly. So far no nails or screws.
Cheers, Marshall.
At least you still have a kitchen to use for assembly, I gave mine up to parts storage long ago.Quote:
Originally Posted by mah
Looking forward to that big grin you're gonna have... :coffeedrinker:
Not grinning yet but starting to smile.
Preparing to glue and screw the carcase.
Hi GM,Quote:
Originally Posted by GM
The links didn't seem to spec a particular PL formula. Were you spec'ing the 375 formula perhaps?
thanks!
Here's a product I used with some success for constrained layer damping. Acts as an adhesive & damping.Quote:
Originally Posted by mah
Available from Hawthorn Audio......Green Glue [GG] - $18.00 : Zen Cart!, The Art of E-commerce.
No affiliation.
Hmm, I dimly recall being on individual product pages, so would have copied whatever was in the address bar.
Anyway, PL Premium is what I've used pretty much exclusively since it became available decades ago and Liquid Nails Sub-flooring/Decking for when I want it to stay elastic for constrained layer construction. What I want to try is the PL400.......
GM
That PL400 Polyurethane Glue is some strong stuff use it a lot. You will pull the wood apart before a glue joint with that Stuff.Quote:
Originally Posted by GM
Ditto the premium, but the 400 supposedly works on wet, frozen wood too, something I could have used last Fall doing the roof had I known about it.
GM
and...?Quote:
Originally Posted by mah
:coffeedrinker:
511B Restoration.
Before: Weathered, oxide patches and rough paint job done to areas visible from front-on.
Initial prep.:
1. Scrape off poorly adhering paint.
2. Sand with Norton NO-Fil A295, P80 to finish-off step 1.
3. Sand with Norton NO-FIL A219, P120 to smooth the surface further but still leave the exposed aluminium areas with enough 'key' for the Metal Etch Primer. You may prefer a higher grit number for a smoother surface.
4. Dust off, water wash and wipe down with tack-rag or rag dampened with a paint compatible thinners.
5. Apply Metal Etch Primer Coat(I use automotive aerosol cans). In the picture below the 'bells' are yet to be etch-primed.
Finishing:
Then comes the sandable primer/undercoat, body filler, primer undercoat, followed by the finish coats. Sanding between coats may be required and a touch up application of the previous coat applied before proceeding to the next stage.
Not difficult. Time will depend on level of finish required.
Dusty, dirty and smelly-outdoor job. OBSERVE SAFETY PRECAUTIONS.
I have a can of paint stripper but have not needed it, so far. Hate using it. Hate cleaning ovens, too.
Cheers, Marshall.
Up and on castors.
Plenty of top/bottom bracing, I see, but those angled cross braces may reduce the efficiency of any 1/4 WL vent loading if it's a MLTL, i.e. they should be on edge to minimize turbulence.
GM
Hi, GM.
All braces are on edge. Do you mean the left to right centre-bottom brace, which is taller than the front to back bottom braces, or the horizontal cross-braces across the middle of the sides?
Greets!
The ones across the middle and ultimately covered with damping. In acoustically small cabs for the intended BW, bracing orientation is irrelevant since there's a ~uniform particle density that just expands and contracts, but as the cab gets long enough in one dimension to make it have pipe action, then it begins to matter. Probably not much in a rectangular cab such as yours compared to a thinner, higher aspect ratio cab, but it doesn't hurt and pointing this out whenever appropriate hopefully will get folks to think in these terms when designing their own.
GM
Thanks for clarifying, GM.
Horns are finished(damping material applied) and front panels checked for clearances. The gap will be fitted with a glued-in panel.
I painted the cab carcase with automotive acrylic from spray cans. Applying several coats the finish still appeared striped. It seems that the spray fan varies in wetness from the centre to the outside. A local auto painter will lay a uniform coat over the current coats and all will be well. Lesson - don't use touch-up spray cans for large areas.
Front panels - speaker holes cut, vent holes yet to be cut, centre bracing panel to be done.
Rear panels - drilled, painted and ready to be glued in.
Front to rear stay to be done.
Yamaha NS 10M on top in the pic for scale reference.
Done many a uniform spray can finish on large cabs, cars, pick-ups by spraying an area and using a fine nap roller to smooth it out, though I doubt one could work fast enough if using a quick dry coating unless maybe a second person was rolling right behind the spraying.
What's the open area in middle of the cab for?
GM
Quote:
Originally Posted by mah
This was my project last year;
Enclusures 225 liter (net)
Width 57 cm. - Deep about 50 cm.
Total height about 135 cm. (middle horn height about 110 cm)
Spray painting (very dark grey + black) must be done this Spring
http://www.hostboard.com/forums/hbmc.../2011/04/7.jpg http://www.hostboard.com/forums/hbmc.../2011/04/8.jpghttp://www.hostboard.com/forums/hbmc.../2011/04/9.jpghttp://www.hostboard.com/forums/hbmc...2011/04/10.jpg
GM, the divider when it has an in-fill piece glued in will form a beam to give the front opening some resistance to racking.
I am getting close to sending you a PM re tuning if you can spare some time.
ALF, that is a fine looking build.
You have given me a deja vu experience. Before I decided to go with the 828 based system I was very taken with some of the high-end JBL designs. The K2 S9800/SE I seriously considered, using Altec components, until I came to my senses.
I changed my mind about the 828 and used the 828 panels I had to go BR/MLTL.
I got this close to building the JBLs:
http://www.spatz-tech.de/synthesis/p...800-9800SE.pdf
http://www.independentaudiovideo.com...itemid=1000028
Have you considered a project thread? I would like to know more about this adventure.
Cheers, Marshall.
The reason for my project was; My best friend owns a very expensive audio system with 2 MCIntosh MC1000 amps a MCIntosh C100 + Audio Note Dac + cdt and of course the JBL K2 S9800SE.Quote:
Originally Posted by mah
So my ultimated goal is to come very close or beat him with of course Altec Lansing speakers.
The basic of my project is het Model 19, only I 'm using the big Altec drivers, in this case 291-16B drivers with 8 ohm diafragms and of course 416-8B woofers.
How and what about the crossover took my a very long time to find out what was the very best solution, but at the end the N1201-8A crossover with some small upgrades and the integration of a tweeter sounded the best.
And the best is in my case is a sound wall, deep and wide, I hate the right in the face, very up front, disco sound.
And of course I hate a system with 500 knobs, no a system must sound perfect with only one knob, and that's the one on your preamp.
Of course my friend with his 2x1000 Watt amps, can create a lot of pressure, but I must say, I come very close with my 2x18 Watt 300B amp. and that was not an easy job.
For my enclosures I used high quality playwood, I glued 3 mm. cork inside, I sprayed a tick layer of some kind of DUM-DUM sealing compound (which used under cars) over the cork, and only about 1,5 cm. glass wool.
The horn I use is a EV HR60, because that horn is made of polyester, and that is not the very best way to build horns, I covered up the outside with about 5 mm. epoxy mortar, to get more massive in the horn. The results are better than expected.
If you want more inside information about the crossover, sent me a PM
No problemo, though I may answer in one of your threads if it's applicable to the masses. BTW, I PM'd you awhile ago through the board about another matter, though in retrospect I haven't had a lot of luck with the hostboard of late, so probably better to respond to it in a PM to my yahoo account.Quote:
Originally Posted by mah
GM
GM, I have sent a reply. I am not sure that the email address I sent it to is current. Could you let me know if you received it?
Cheers, Marshall.
ALF, thanks for the info. It's good to see such an ambitious Altec project. Of particular interest to me because I put it into my too-hard basket. I think this is what this forum is all about, going forward with ideas incorporating Altecs into new applications as well as celebrating what has already been achieved.