828 vs 825 Cab?

[v847]

What is the diff. between these as far as dimension and years of use??

Thanks,
V

[jnorv]

Not being an expert on the subject, but I think the main difference is that the 825?s were plywood and the 828?s were particle board. That and the horn flare volume is sealed in the 828?s. I ,also, think that there were 5/8?s and 3/4 inch 828?s. I think the basic dimensions were the same.

Jim N

[Roland N R]

Best to review Jim Dickenson's "borrowed" article in Sound Practices website. Look under Altec.

Basically the early 825 had a two piece back and used 5/8" plywood which was poorly reinforced. They allow use of the older 15" speaker frames and newer 16" frames and had XS bass cab volume due to non covered horn flares.. The 828 cabs allow 16" speaker frames, have been made of 5/8 and 3/4" particle board and have had the horn flares covered to give the correct bass reflex volume of about 9-10 cubic feet.

Refer to the article for more details.

[Altec19]

Hi All,

Here's a link to the Sound Practices site:

http://www.soundpractices.com/altec.html

Here's the relevant material from the "Small VOT" article:

The first cabinets, the 825 style (825's have a two-piece rear panel with only the top part removable), were made out of 5/8" plywood with minimal braces. These cabinets use a great deal of energy in wiggling the box.

The 828 (introduced in 1970) was first built for rock musicians The first ones had 2x2 rails on the outside of the full length rear panel to protect the crossover or musician's BiAmplifier during moving. It was built with 3/4" material and was far stiffer than the previous 825. It was introduced to theatres in 1976. In 1981 the 828G replaced the 828 and changed the 2x2's on the back to an internal brace. The internal flare volume was isolated and unfortunately the box material reverted to 5/8" particle board. This enclosure needs more bracing.

In early 1989 the 828H replaced the 828G and is made with much stiffer 3/4" particle board, it still could use more bracing. All 825-828 cabinets are not rigid enough in the horn flare. This degrades the midrange performance.

For many years Altec published plans for people to build this cabinet and many were built. Sometimes builders did a fine job, other times the result was cabinets that looked like 825-828's but were very flimsy. You can usually tell if cabinets were factory units by the "Voice of the Theatre" decal on the side. Unfortunately, I have seen a few miserable homebuilt examples
with the V.O.T.T. name on them as the decal was available from Altec literature.

The 825 and early 828's have a little too much reflex space in them. The 828G and current 828H are right on, they just need
bracing.

Later . . .

[Todd W. White]

The 825 was made of 5/8" plywood, and had a two-piece back. The early 828's were 5/8" plywood, had a one-piece back, and had rails on the back. The later ones were particle board.

The last 828, the 828-G, was made of 3/4" particle board, but may have gone back to 5/8" at the end.

The horn flare on the early models were made of curved 3/8" plywood, the last ones were bent 1/4" plywood.

Acoustically, they were the same - the internal dimensions were identical.

<font color="#FFFFFF"><font size="1">[ October 20, 2003 11:42 AM: Message edited by: Todd W. White ]</font></font>

<font color="#FFFFFF" size="1">[ October 20, 2003 11:43 AM: Message edited by: Todd W. White ]</font>