Paul and All -
Since I don't have WinIsd loaded on the machine I am using, I tried some hand-calculator work and found that a Qtc of .707 gives an interior volume of 1.09 cubic ft. That sounds very reasonable. The very weird thing is that a Qtc of .5 gives me an interior volume of nearly 8 cubic feet! Can this really be?
Regards,
Karl
Since I don't have WinIsd loaded on the machine I am using, I tried some hand-calculator work and found that a Qtc of .707 gives an interior volume of 1.09 cubic ft. That sounds very reasonable. The very weird thing is that a Qtc of .5 gives me an interior volume of nearly 8 cubic feet! Can this really be?
Regards,
Karl
Karl,
That doesn't look quite right. .707 should be considerably bigger. With stuffing, I often advise around 2 cu ft sealed (or a little bigger), smaller for HT. If you are not going to use BSC, then some folks like the higher Q alignments to get a little more midbass. And, I always recommend wide baffles and wall or corner placement when not using BSC. There are plenty of calculators online, including the online version of winids.
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
That doesn't look quite right. .707 should be considerably bigger. With stuffing, I often advise around 2 cu ft sealed (or a little bigger), smaller for HT. If you are not going to use BSC, then some folks like the higher Q alignments to get a little more midbass. And, I always recommend wide baffles and wall or corner placement when not using BSC. There are plenty of calculators online, including the online version of winids.
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
I'm sure some are playing happily in sealed boxes. Not too many folks actually post their projects. I'm as guilty as any one else! I always start with the intention to document my build, but I rarely get around to it. Another project usually seems more pressing. At first I was also saddened by how few customers I heard from after I shipped the speakers. Then it occurred to me that I generally never follow up with folks I buy stuff from unless I've got a problem. So perhaps no news is good news.
The Betsy and BetsyK have sold nearly dead evenly. I didn't expect that they would, but so it is. Generally, I never sell them same number in a given month. One month everybody will buy Betsys, the next month BetsyKs. But over time, it always evens out.
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
The Betsy and BetsyK have sold nearly dead evenly. I didn't expect that they would, but so it is. Generally, I never sell them same number in a given month. One month everybody will buy Betsys, the next month BetsyKs. But over time, it always evens out.
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Paul -
What is the advantage of 3/4" ply over 1/2" ply? Is a "dead" cabinet that important? I would use some bracing. I would surface mount the driver and do not want to carve out too much wood around the rear of the driver in order to create clearance for the holes in the basket.
Regards,
Karl
What is the advantage of 3/4" ply over 1/2" ply? Is a "dead" cabinet that important? I would use some bracing. I would surface mount the driver and do not want to carve out too much wood around the rear of the driver in order to create clearance for the holes in the basket.
Regards,
Karl
Karl,
Even if you don't flush mount, the basket covers the first 3/4" anyway. Generally you do not want a terribly resonant cabinet. We fullranger folks tend to not make them as heavy and braced as the multiway guys, preferring a "livelier" sound. But still, 3/4" is the norm. Bracing never hurts, but on a smaller, I wouldn't brace the baffle too close to the speaker. Something like the BIB has such big panels that more bracing is good. With mine, I even doubled up the front panel to get 1.5" thick (and then I did cut the back panel so the driver had room to "breath").
3/4" is really the standard in speaker building. Some really small cabinets can get by with 1/2". So can cabinets that are very heavily braced. For example, I have 1/2" sides cut for my tapped horn subs, but they are so heavily folded and have such a narrow line that sides are essentially over-braced. When it comes down to it, it is much easier to build a less braced 3/4" box than a adding more braces to 1/2" ply.
If you read much about cabinets, you'll see that MDF is the norm in the multi-way world. It is certainly dimensionally stable (no warps like ply). But, it is also less stiff. Most of us fullrange guys think it sounds bad. It is also really unhealthy stuff, especially if you have a big vent or leave the outside unfinished. And the dust is nasty. You'll see that Baltic Birch (different and more expensive than big box store "birch ply") is the standard for really nice builds. I'm pretty happy with AC grade pine for most things. It has nicer internal plys than much of the "cabinet grade" big box store sheets that have pretty but thin veneers and terrible internal plys. My BIB's were a baltic birch, but that was again due to the large panels.
I assume that more than answers your question!
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Even if you don't flush mount, the basket covers the first 3/4" anyway. Generally you do not want a terribly resonant cabinet. We fullranger folks tend to not make them as heavy and braced as the multiway guys, preferring a "livelier" sound. But still, 3/4" is the norm. Bracing never hurts, but on a smaller, I wouldn't brace the baffle too close to the speaker. Something like the BIB has such big panels that more bracing is good. With mine, I even doubled up the front panel to get 1.5" thick (and then I did cut the back panel so the driver had room to "breath").
3/4" is really the standard in speaker building. Some really small cabinets can get by with 1/2". So can cabinets that are very heavily braced. For example, I have 1/2" sides cut for my tapped horn subs, but they are so heavily folded and have such a narrow line that sides are essentially over-braced. When it comes down to it, it is much easier to build a less braced 3/4" box than a adding more braces to 1/2" ply.
If you read much about cabinets, you'll see that MDF is the norm in the multi-way world. It is certainly dimensionally stable (no warps like ply). But, it is also less stiff. Most of us fullrange guys think it sounds bad. It is also really unhealthy stuff, especially if you have a big vent or leave the outside unfinished. And the dust is nasty. You'll see that Baltic Birch (different and more expensive than big box store "birch ply") is the standard for really nice builds. I'm pretty happy with AC grade pine for most things. It has nicer internal plys than much of the "cabinet grade" big box store sheets that have pretty but thin veneers and terrible internal plys. My BIB's were a baltic birch, but that was again due to the large panels.
I assume that more than answers your question!
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
7.25" is a good middle ground and gives you a little leeway if you don't get the screws perfectly aligned. You could go a little tighter if you are really good. When I used to cut the hole freehand (Rotozip, no jig), I'd aim for more like 7.375" to be sure I'd be o.k.
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Fancy: 10-32 socket head cap screws (into brass inserts, T-nuts, etc)
Less Fancy: #8 black pan head coarse thread
Real cheap: drywall screws
I always use four screws even though there are eight holes.
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Less Fancy: #8 black pan head coarse thread
Real cheap: drywall screws
I always use four screws even though there are eight holes.
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
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Well, a little bigger than 2. Notice that I didn't say 2 yielded a .707 q, but it might get pretty close with some stuffing (which the online calc probably doesn't include!). And as fullranger folks tend to avoid BSC, and all fullrangers are subject to doppler distortion, I tend to recommend boxes a little smaller than .707 for most folks. You are of course free to build whatever size you want, and encouraged to share the results!
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
I'd put some thing on the back, top and one side wall. Eggcrate foam, or maybe a couple layers of that foam carpet pad that is made from chunks of different densities. Not for stuffing, but to control higher frequency reflections. Then I'd probably start with a pound of polyfill in each one. Those are my suggestions for cheap and easy. Fiberglass performs better, but is worse to work with. The right type of wool is surely great, but more expensive.
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
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