Rerurn to Romy the Cat's Site
In the Forum: Horn-Loaded Speakers
In the Thread: Macondo’s Midbass Project – the grown up time.
Post Subject: The Iron RodPosted by Paul S on: 7/17/2010
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Yes, I "see" it.
The "doubled 2X" beams are very rarely used anymore, mostly because they rate much lower than a "comparable" solid header/beam/etc. A solid 4X10 is rated for 8' clear span under that condition, or maybe less with the centered "point load" from the listening room ridge. As it is, I'd add sand a little at a time...
The "suspenders" you propose are called "rods", and they actually serve the same purpose as wooden webs would in their stead, except, obviously, the rods can be nice and thin, so as not to interfere much with the sound waves. Although the rods do re-load the rafter, if you add them every 2' or so they will effectively re-distribute the rafter load, too.
You might structurally remove some of the vertical load from the double 2X10 beam by installing true valley rafters; but this should be laid out carefully before any common rafters are cut, since the exact layout of the to-be jack rafters would be critical for a tight dry fit of the framing members of the to-be true dormer valleys. This would open up the space entirely, and, again, it would also unload the beam. Your carpenter might not want to tackle such precision work under those conditions, but he will likely know what I mean.
Best regards,
Paul SRerurn to Romy the Cat's Site