A7 Project

**Mustang Marvin** · September 22nd, 2009, 01:00 PM

Bowtie,
Why don't you email me with your best price if you don't want to post a price here on the forum.
Thanks

Thanks Jon,
I'll keep these in mind as well.

Can anyone tell me the difference between the 416 a, b, and c?
Which one would be best for my project. As I said I have 902's for the HF so I'm good to go there.

**gearfreak** · September 22nd, 2009, 02:03 PM

Pretty plywood cabs. Strong corners. Good stuff.

I think I liked by plywood w/416 better than my 'mdf' with 515-8G. Don't know how much of that was the cab vs the speaker, different sizes so could not swap to test.

Just a curiosity that you may want to note - While you have the woofers out, check/photo the motorboard/baffleboard/where they mount.
Mine had indication of who made the cabinets (stamp was 'hill craft mfg' IIRC... posted on some other thread) obscured by mounted woofers.

Old (and all?) 416-8A's (A's) are alnico magnets. They are also suitable 'only' for rear mounting (the front of the speaker frame, mated to the rear face of the baffle) , due to the 'flutes' (for lack of a better term) which reinforce the rear side of the frame. Latter models / revisions of Altec woofers seem to have eschewed this in favor of a flat surface (like bowties') which then allows mounting the speaker from either face of the frame.

As for additional diffs, check the lansing hertiage site, altec pro site, or greatplainsaudio for original spec sheets on many such drivers. Just note which frame size you are reading about. (apparent from pics usually)

**gearfreak** · September 22nd, 2009, 02:21 PM

PS. You will find numerous posts/discussion about port size and A7 style (828/825) cabs here on the board.
Those look like a pretty good start to me, similar to what I ended up with on mine, though perhaps longer and thinner of a shape than ideal.

'That old saw: A7 port size' (or very similarly phrased) is one of the threads that comes to mind.

**Mustang Marvin** · September 22nd, 2009, 04:46 PM

More pictures...
Hostboard

The top of one cabinet has had the top layer of plywood damaged. Obviously when the cabinet was flipped. I will remove the rest of the top layer and replace it with a veneer of Birch, then repaint both cabinets. BTW they are 825's from the mid 60's according to my research. I can't seem to find any plans for this model. only the 828.

Dang, those 416B's of Bowties look awesome. I bet he wants a fortune for them. They are, I believe, exactly what I need...

BTW, can I use 2 inch fiberglass instead of the 1 inch. I need to replace the existing fiberglass. It appears to only be on the bottom and sides next to the woofer. I believe this is correct for this model.

**Audio_by_Goodwill** · September 22nd, 2009, 04:50 PM

Originally Posted by gearfreak

Old (and all?) 416-8A's (A's) are alnico magnets. They are also suitable 'only' for rear mounting (the front of the speaker frame, mated to the rear face of the baffle) , due to the 'flutes' (for lack of a better term) which reinforce the rear side of the frame. Latter models / revisions of Altec woofers seem to have eschewed this in favor of a flat surface (like bowties') which then allows mounting the speaker from either face of the frame.

That's not entirely accurate...... there were 416-8A's made that used the newer 16" frame. They probably aren't as common, Though.

**Mustang Marvin** · September 22nd, 2009, 06:13 PM

Dang,
416A's
416B's
416C's
Now I AM confused...

**Old Guy** · September 22nd, 2009, 06:18 PM

Originally Posted by Audio_by_Goodwill

That's not entirely accurate...... there were 416-8A's made that used the newer 16" frame. They probably aren't as common, Though.

Yes there were. At the very tail end of production. Since it was a year or two production versus many, they aren't as common.

The new frames were phased in, there is not a hard and fast switchover. Units from the last couple years can have either frame.

**Old Guy** · September 22nd, 2009, 06:23 PM

Originally Posted by Panomaniac

Can those 418s be reconed into a 416-8A? Is the magnet the same? Or would it be close enough for the A7 use?

I would discuss it with GPA....

I have looked at the internals and they look the same to me.

But then I have seen posts saying the MI speakers have different pole pieces.

I don't think that's true, and don't remember who said it, but he had enough cred to make me wary.

It would be sad to tear up a pair of "survivors" though.

**gearfreak** · September 22nd, 2009, 06:38 PM

... Good catch on the late model 416a's guys.
I could not remember for certain, hence the 'and all?'.

Originally Posted by Mustang Marvin

Dang,
416A's
416B's
416C's
Now I AM confused...

Don't worry. It gets even more fun when you look at 604 and 515 variants. ;-)

So, as an 825, it is setup for the smaller frame size, correct?

In that respect, the larger frame may (may) barely fit. I believe that they may have spaced the latter model frame holes for such an application - but I have not done it myself. I don't know if there are other clearance issues. Someone else here who actually knows can chime in... or you can measure and compare to the spec sheet(s).

I do know (from experience) that a (small frame 416-8A) will not 'naturally' fit in an 'A5' 828 cab which does fit it's 515-8G 'naturally'. We assume the 515-8G is OEM.

**bowtie427ss** · September 22nd, 2009, 09:19 PM

The small frame bolt circle is equal(or darn close to it) to the minimum diameter of the large frame bolt circle.

I'm pretty sure you can get a large frame in an 825 w/ no mods or hacking, and even get the T-nuts to line up. It will be a tight fit with the frame all but touching the inside of the top of the cabinet, but the 825 print spec's the center of the woofer opening at 8-1/16 inches from the inside of the top panel.

The 825 spec's a 14-9/16 bolt circle same as that of the small frame woofers, and the 828 a 15-1/8 bolt circle which must be fairly close to the largest diameter the slots in the large frame will accept.