Enclosure

[nikki1]

Good day Guys,

This is my first post on here with some questions concerning enclosures. I have a pair of 411-8A's, 511B horns (don't know the drivers-no id on them) and 501-8A xovers. The amp is a Marantz 1060 (250W).They were purchased by my brother back in the early 60's an, and I have them. Haven't been used much and still work fine.

I want to build a pair of enclosures for the woofers to take advantage of what they offer. I freely admit I'm not an audiophile, although I do appreciate good sound. There's a danger in this in that I tend to be pretty anal about things and if I don't restrain myself I'll be looking for that last hertz? and wanting to shatter windows. The system will be used for casual music listening and as a sound system for TV.

The room they will be in is 36'x34'. Hardwood floors, one open room (post and beam) with the ceiling finished in knotty pine and the ridge 28' high. When watching TV our position is about 10' form the speakers. Slight overkill for that but when listening to music around the room it oughta' be OK.

After poking around on the web I think either an Altec 620 or 825 (A7 500?) enclosure would do me nicely. I have both the ability and tools to build either one, although the 825is a little more work.

Any comments or recommendations? Even a different enclosure? Infinite baffle versus ported?

Questions-

1- Is there a certain ratio between the HxWxD of and enclosure? XCan they be played with as long as one maintains the same volume?

2- What's the reasoning behing covering part of the woofer cone in the A7 vs having the whole thing exposed as in the 620?

3- Can the two bottom panels on the A7 be made as one? I can't see nay reason for having two.

4- How critical is it to align the voice coils above each other as opposed to being staggered?

This has been pretty verbose, and for that I apologise but the more info I can give the better the answer I get.

Thanks for your time, info and patience,

Lee Halverson

[bowtie427ss]

1- Is there a certain ratio between the HxWxD of and enclosure? XCan they be played with as long as one maintains the same volume?

It's called the "golden" rule or ratio. It can be bent via certain compromises. You'll find that "hifi" is precisely the point where satisfaction meets compromise, a differing point for most of us.

2- What's the reasoning behing covering part of the woofer cone in the A7 vs having the whole thing exposed as in the 620?

You're comparing two very different enclosure types, the A7 is a constrained throat midbass horn with exaggerated bass reflex volume in an attempt to extend the usable LF response. The 620 is a "golden ratio" bass reflex cabinet. The 411 woofer doesn't belong in either of them.

3- Can the two bottom panels on the A7 be made as one? I can't see nay reason for having two.

Yes they can. They were made removable to accept internal horn mounting for both the 811 and 511 horns while observing more or less proper port area. There are many discussions here and at other forums on the topic of "re-tuning" the A7 port.

4- How critical is it to align the voice coils above each other as opposed to being staggered?

It's not per se`, more critical is the alignment of the acoustic centers of the horn/driver combination with that of the woofer.

This is just my .02, there are others here with far far more knowledge than i, and there will likely be some dissent from what is considered "ideal" A7 tuning.

You might also look at some of the other fairly fresh 411 discussions here on this board to get an idea of the best use for them.

[nikki1]

Well so much for those ideas. If not the 620 or A7 what would be a good home for the 411's?

Thanks for your responses.

Lee

[bowtie427ss]

A sealed or even perhaps a tuned ducted port version of the 620 might be a suitable home.

I strongly encourage you to review the other threads currently running regarding the 411, there is much useful information to be assimilated from them. Perhaps a clone of the 9846 monitor or clone of the Barcelona home speaker might appeal to you. You have the bulk of the components minus the 30904 attenuator network which is easily duplicated.

FWIW, Altec only used the 411 in sealed alignments, but it has come to light that Bass Reflex is a possibility for them too.

I would also encourage waiting for some of the other experts here to chime in.

You have some very good components, and there are fellas here who can advise you in a manner that will save you a lot of hassle and help expedite you on your way to success.

[nikki1]

Clearly a sealed enclosure would be the easiest of all to build. I will dig around in here for scoop on 411's and await more comments from other members.

Thanks again,

Lee