New Altec speaker boxes Part 2

[GM]

I believe I've expressed enough opinions in this thread already.

[bigjunglejim]

GM, your opinions are welcome, even after the boxes are built.

Without question, after the boxes are built, I'm sure there will be a whole bunch of "Monday morning quarter backs" offering their opinions. My thinking has gone from exact clones to a box with slight improvements and a lot of options.

With all the recommendations I've gotten about adding more bracing, you'd think a HDF would be a better choice than LDF Altec used. Was HDF even available when the 620 was designed? HDF costs more than MDF or LDF, perhaps that was a consideration when Altec designed the 620. Come to think of it, I don't recall any Altecs built boxes using HDF. All the Altec factory boxes I've seen made out of fiberboard were made using a low quality fiberboard with just enough plastic to hold the sawdust together... I'd call it LOW density fiberboard or LDF. Was this done for economic reasons or am I missing something?

[bigjunglejim]

One more question..... This is a BIGGIE. What do you people think about having the factory do the cutting, without assembling the box? Would it be better if the 620 is offered as a kit to be assembled by the consumer?

[LICORNE]

Sooner or later those who want speaker cabinets
wiil figure out that you can bring your plans to any hardware store and they will cut the wood for you . Much cheeper .All you have to do is assemble it.

...................................

[bfish]

From a Wednesday evening waterboy;

http://www.aes.org/e-lib/browse.cfm?elib=848

[bigjunglejim]

Call me cheap. If I can find the information for free, I'll take advantage of it. And, pass it on. Here's a little something from JBL.

JBL....
THE MOST COMMONLY ASKED QUESTIONS ABOUT BUILDING ENCLOSURES

[16]
Q: What is the best material to use for building enclosures?

A: For home and permanent installation use, high density particle wood is the most cost-effective material for general enclosure construction. The best wood to use for portable enclosure construction is 14 to 20 ply per inch Finland birch type. Birch plywood is very expensive however, and a carefully braced enclosure made of high grade void-free fir plywood can do the job just as well in most cases. The thicker you can make the cabinet walls, the better the results will be because of reduced wall vibration and resonance, but the tradeoff is cost and weight. Enclosure walls should be cut so that edges form an air-tight seal when glued together. Cleats and caulking can also be used if needed to insure a good fit and tight air seal.

[17]
Q: Is bracing necessary? How much should be used?

A: Bracing should be added to the enclosure interior to minimize enclosure wall vibration. Enclosure walls simply cannot be stiff enough since wall vibration indicates that energy is being wasted to move enclosure panels rather than moving air. 25 X 76 mm (1 X 3 in) pine bracing fixed on edge with glue and screws to the enclosure walls will help provide the minimum necessary stiffening without affecting the internal volume significantly. If you are building large subwoofer enclosures, bracing with two-by-fours works better, though you should take the bracing volume into account since a 3 m (10-foot) length takes up 12.9 liters (0.36 cubic foot) of enclosure volume.

[TnTn]

Convergence,

Here in the US, it's difficult to find a good hardware store that will do the kind of precision cuttings required for a speaker cabinets. Some places don't tell you, but they won't guarantee accuracy better than 1/4 of an inch. Imagine trying to recut most of the pieces using a circular saw back home and especially if you don't work with wood that much. Now your boxes have the wrong dimensions and such.

I won't go through this again.

T.

[LICORNE]

Our large hardware warehouses have a cutting department. The guys in there are semi retired construction workers. They are very acurate
at cutting wood.

They would assemble it for me for additional cost. How's that for service.

......................................

[Old Guy]

Originally posted by TnTn:
Convergence,

Here in the US, it's difficult to find a good hardware store that will do the kind of precision cuttings required for a speaker cabinets. Some places don't tell you, but they won't guarantee accuracy better than 1/4 of an inch.
I won't go through this again.

T.

<font size="2" face="Verdana, Helvetica, sans-serif">Quite true- which is why I would NEVER buy at a hardware sote unless I was taking it home to cut myself

However, try "Lumber Yards"

I live in a decent sized city- columbus ohio- but I have a choice of maybe a dozen places that do a great job. I'm sure there is one close to you...

Having lumber cut at a hardware is akin to trying to buy a professional camera at an appliance store- best to go to a real camera dealer.

[bigjunglejim]

The factory I've mentioned several times in this thread if swamped with work building interiors for Carl's Jr. It looks like it may be after the first of the year before I can have the 620's made unless I find another factory willing to do the job sooner. I'll keep you posted.