New Altec speaker boxes Part 2

[bigjunglejim]

Gary, you have put forth some good stuff.

I for one have never seen spray paint on fiberglass. As I said, I have 5 of them and they all have the cloth. I don't doubt you, I'm trying to understand what Altec did and why. As for the difference in the wood under the speaker flange, your explanation makes sense. I thought about the the cabinets being oiled but I never thought about the gasket bleaching the wood or sucking up the stain, especially if the gasket on the speaker was made of a paper or cardboard like substance. Like I said, mine aren't like that.

I looked at Jeff's building plans listed in the link below. The building plans calls for the fabric. I'll copy and paste below where to find the details and the definition of "scrim"

http://home.earthlink.net/~jmarkwart/index.html

Jeff Markwart's Corner
Vintage Altec Lansing Model 19 Cabinet Plans
Model 19 Material & Finish Data
Item #12 "COVER FIBERGLASS, VISIBLE THROUGH PORT, WITH BLACK SCRIM" (I copied and pasted this, I didn't use the upper case letters).

"The Collaborative International Dictionary of English v.0.48"
Scrim Scrim, n.
1. A kind of light cotton or linen fabric, often woven in
openwork patterns, -- used for curtains, etc,; -- called
also India scrim.

[bigjunglejim]

One more point of interest. In the Altec plans that Jeff posted (see the link in post above) there is a cross brace across the back of the bottom section of cabinet. I can't make out the date on the prints. Perhaps this was a later version than yours and it had improvements such as the diagonal brace and fabric. One of my 19's has the woofer removed and I just went and checked. I can feel the diagonal brace behind the fiberglass and fabric.

[bigjunglejim]

GM... You wrote

"At least into the early '80s, Altec was fairly particular about its wiring, specing it as the electrical component it was in the signal chain, so I recommend using whatever they did with the original, ditto when (re) wiring XOs and choosing its components WRT resistance, inductance, capacitance. That, or use what you want and add series resistance if needed to balance out the system in the form of the appropriate small gauge magnet wire or similar if you don't use an amp with adjustable damping"

If I only supply wire that goes from the terminal to the XO, would it still be critical to do as you suggest? Perhaps once the signal leaves the XO going to the drivers it would make a difference. The way I see it, until the signal hits the XO the wire going from the terminal to the XO is a convenience item so you wouldn't have to attach your speaker wire directly to the XO. What do you think? Also, where can I find the specs for the wires Altec used?

[gamalot]

You are correct about the diagnal brace along the back panel. I never had my insulation off but did check and they do have it.
As for the paint or fabric blackening, you have seen it and I posted the pics above. Every 19 I have ever owned had black crusty type paint just like in this pic and none ever had fabric.
I would like to see a pic of one of your cabinets with the fabric if you can be sure this was not added later.
I don't think it matters how it is accomplished, paint, fabric or any other method will do but all my original cabinets just had something like a crusty undercoating sprayed in this area that does flake off.

This cabinet is not a 19 but it is how I will build the boxes when I get to that project and I will add some diaginal bracing in them as well.
Every broken 19 cabinet I heve seen is broken along the seams so this should support them and add some strength where needed.



Gary

[[email protected]]

These were bought new in 1977. No sign of any cloth...... Mark

http://www.pbase.com/mazda/image/76454844

[gamalot]

Yours are the same as all the ones I have had.

Looks like your bases are gone! This is what causes the typical cabinet seam separation I see with many 19s. Keep them up and off any type of floor that they can wick moisture from.

Yours do have some nice figuring in the Walnut.

Gary

[bigjunglejim]

I talked with Bill at GPA. I discussed my plans on having some 620's build to offer for sale. I wanted to know his thoughts on retuning the 620 enclosure for his new 604's. He recommended not retuning the cabinets. He said they are fine the way they are.

My brother told me the factory is having second thoughts about building the 620 for me. It seems they were building cabinets for another and it became a pain the the neck for them. They haven't ruled it out. I'm keeping my fingers crossed.

[Sounder]

JJJ,

I suspect the "pain" they are referring to is all the internal bracing.

My suggestion would be to have them construct the carcass (with corner bracing, cutouts for speakers and tuning port) but leave the majority of internal bracing for the end user. These are very easily added and would save shipping weight.

You could include a set of directions (recommendations) on the internal bracing along with the sound damping requirements. I personally prefer densified polyester batting (used by upholsterers) since it is so benign to work with. I bought a bunch of the stuff and the remainder I am using for making beds for my dogs.

Don't forget that there are plenty of good cabinet shops out there looking for work.

John

[jmarkwart]

JJJ,

The original drawing date of the Model 19 plans on my site are April 1976.

Jeff

[jmarkwart]

JJJ,

As to wiring - my old A7 assembly instructions from 1965 lists the internal wire as #16 stranded cellac, whatever that is. It appears to be the same wire that Altec used to wire their crossovers and also jump from the compression driver cap connectors to the voice coil terminations.

It's noisy - I can hear white noise from Altec horns using the stock wire. I switched to Vampire long-crystal OFC copper years ago for Altecs. It's dead quiet and smooth.

Jeff