If you use a driver like this in a couple cubic feet it would still be movable:
Peerless by Tymphany STW-350F-188PR01-04 15" High Power Subwoofer
Peerless by Tymphany STW-350F-188PR01-04 15" High Power Subwoofer
The bit of wood with holes in will bend more easily than one without holes. Maybe 60% more.
I think the holes should really be of different sizes when used typically. Looking at baffle step talks, some holes between 50 and 150mm would be resonant within the audible range. I'm just skirting round the idea though, I have not looked in any detail. I avoid multiple use of the same dimension though. Often using a jigsaw for such jobs, knowing that being a bit rough will reduce the area of parallel surfaces.
edit: It's the subwoofer forum. Doh.
That'll help.
I've run a half dozen pieces just in from the driver hole from front to back using PL glue inside and a screw front and back and that supported the driver a lot better. That PL construction glue is strong stuff and you could probably get away easily with no screws.
Grant.
the little Karlson cabinets (KK-Audio, Transylvania Power, Acoustic Control, etc.) all used 3/8" all-thread rod to brace the "wings". It ran all the way from the wings through the inner baffle to the back and reduced modulation effects as even 3/4" Russian birch plywood would flex in this application.
3/4" dowel rod and closet poles are pretty good too
3/4" dowel rod and closet poles are pretty good too
K15 made a good sub for John Tucker of Exemplar - it was re-tuned down to around 30Hz with 2 3" PVC elbows, loaded with low fs Altec, then boosted like a 6th order reflex. I tried it with an Altec 416Z - very articulate - perhaps due to Altec's motor and low moving mass. That said, I can't guess how much the front chamber would come into play for subwoofer use.
with the old K15 vent spec of 4.5" wide by 9" talle, there's plenty of room to mount the new vents on a board right over the stock vent. I think Exemplar used "street-el" with flange on one end. I used regular elbow with both flranges and it fit nicely. Exemplar said the modified Karlson was the only sub at the time which would keep up with their hybrid (A7- like) horn.
looks like roughly 28Hz with this old SpeakerWorkshop plot
with the old K15 vent spec of 4.5" wide by 9" talle, there's plenty of room to mount the new vents on a board right over the stock vent. I think Exemplar used "street-el" with flange on one end. I used regular elbow with both flranges and it fit nicely. Exemplar said the modified Karlson was the only sub at the time which would keep up with their hybrid (A7- like) horn.
looks like roughly 28Hz with this old SpeakerWorkshop plot
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So this brings me to some cabinets I want to have made, and maybe a matching table. I have a rustic table, made of pine, LOVE the table and the look BUT every little thing scratches it.
- How do birch and spruce compare for surface hardness/scratchability?
- It was a bit typo'd but I think you said you felt 1/2" spruce ply was as stiff as 3/4 baltic?
Because to make large cabinets, which would go on casters to spread apart for wider staging when nobody is home, I'd sure consider thinner ply and bracing/damping. Maybe modify the drivers so I could fill the enclosures with specially absorptive Jello-or Jello Biafra ha ha.
"How do birch and spruce compare for surface hardness/scratchability?"
Spruce is softer.
Try a google search like "Janka Rating timber" or "Janka rating X", where X is the species of interest.
Most of the woods with high hardness are rare / exotic / exploitative / not available as plywood.
...so if you want a hard (scratch proof) surface that looks like timber, I'd recommend strand woven bamboo.
You can laminate this onto a normal ply substrate. That gives the nice finish with a bit less expense (thick bamboo panels are rather expensive).
Spruce is softer.
Try a google search like "Janka Rating timber" or "Janka rating X", where X is the species of interest.
Most of the woods with high hardness are rare / exotic / exploitative / not available as plywood.
...so if you want a hard (scratch proof) surface that looks like timber, I'd recommend strand woven bamboo.
You can laminate this onto a normal ply substrate. That gives the nice finish with a bit less expense (thick bamboo panels are rather expensive).
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