7 or 4, room shape, cabinet materials, etc. [message #63406] |
Fri, 16 July 2010 09:24 ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
mfaughn
Messages: 2 Registered: April 2010
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Esquire |
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Hello,
New here. I've just got some 2226H on the way. Now I'm trying to decide what to do with them, 7pi or 4pi. Here are a couple of questions I have so far...
1) MDF or plywood? Does it matter much? Appearance doesn't matter a whole lot...might even have them painted as I've got some very talented artists at my disposal.
2) What is a good corner? I understand that both or these work well in corners but that the 4pi can also manage against a wall too. My room is 20x24 and there is a very good chance that the speakers would need to be placed in the corners 24' apart. Also, there is likely to be two 4x8 glass windows between them on this wall if that matters. It seems like the 7pi is the better speaker if one has the right space for it but that the 4pi is more versatile in placement options. I suppose I could build the 4pi and then work on the cabinets for the 7pi and transfer the drivers.
Thanks,
Michael
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Re: 7 or 4, room shape, cabinet materials, etc. [message #63409 is a reply to message #63406] |
Fri, 16 July 2010 15:30 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18757 Registered: January 2001
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Illuminati (33rd Degree) |
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"What is a good corner?" That's a good question.
The biggest thing (other than the obvious, no rattling furniture or windowpanes, etc.) is the corners shouldn't be too far apart. When you have a rectangular room with a long wall and a short wall, this approach only really works well if the corners are unobstructed and they are at each end of a short wall. The reason you want that is you want to be able to sit behind the point where the forward axes cross.
The spectral balance is good everywhere in the room, but the channel balance is only good if you're sitting between the speakers, equidistant from each one, except for the special case where you're behind the crossing of the forward axes. In that area, you can move side to side a fair amount and still have good channel balance. This is because movement away from a speaker simultaneously moves you closer to being on-axis with it. This has a self-balancing effect. See the posts in the link below, especially the ones on placement and toe-in:
As for the cabinet material, I prefer MDF for its acoustic properties but Baltic Birch for its architectural properties. MDF is non-resonant because it's really just a bunch of sawdust held together with white glue. But it turns to mush in the presence of moisture, and even humidity can make it swell. Sometimes, after a while, in humid environments, you can see the seams underneath veneer where MDF is glued together. Baltic birch is much more durable. But like any other plywood, if there are voids, then there can be debris in the void that will buzz. Baltic birch seems to me much better than other plys in this regard, but it is always a concern. Even if the wood doesn't buzz when a cabinet is first built, if there are internal voids, some debris can break loose over time and a cabinet can develop a buzz.
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