sealed alignment...now thats where i'd start, before i cut any vents. so accurate, so fast. or tune to 16 hz...hmmm
If there is accomodation to get back into the cabinet, a removable bottom, back, top, or front, you could cut the front baffle port opening to the correct minimum size and use a separate port "box" of any length to attach to the back of the front baffle. Cleats are going to be your friend in that type of construction.
I've almost relegated myself to a two part front baffle for my Altec cab's. There is just no easy way around getting back into the cabinet should the need arise. I can see a change of stuffing density and port modification as two of the reasons to allow for that.
sealed alignment...now thats where i'd start, before i cut any vents. so accurate, so fast. or tune to 16 hz...hmmm
"those sounds to which no definite pitch can be assigned are usually classified as noise"<br />harvey fletcher-1928
Total vent length, so for a 0.75" thick cutout, its matching duct would be 3.25" long.Originally Posted by Altec Best
OK, then Pano's suggestion is one option, though I suggest you use WE9's cleats regardless and make them beefier if rear mounted.
Cardboard tubes are fine if a grill is used, but are generally a pain to make nice looking, so plastic pipe is your friend here for typical size vents. If you work it out though, the slot is a close enough 8" i.d. pipe, but 8" o.d. is what's available and fairly expensive. OTOH, cardboard tube diameters are i.d. IIRC and it's large enough to fairly easily paint or wallpaper (been there, done that).
(8) 3" plastic pipes would work, though for 25 Hz they would need to be around 5" long each due to wall friction losses. These could be attached to a removable veneered plate with just a long slot in the baffle. WRT to blind fastening it, Velcro it with the heavy duty grade. Be careful though, use too much and you'll need a crowbar to remove them.
If you're dead set on a one piece baffle though, might as well leave it finished and use side vents.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
All great ideas, Thanks Guys !! :2thumbsup: I will have the ports done last to allow for collaboration. Hmmm now I really don't know what to do.What is the easiest to do here.At this point in the game i'm ready to get them done ASAP. I'm ready to get them home so the real fun can start "Tweaking" that reminds me, I think I need a Crossover real soon ! :lollipop:
Thanks Again Guys !
Easiest? Get some ~6" diameter plastic drain pipe and either just cut snug fit holes in the bottom back left/right corner sides to corner load each vent to reduce their otherwise increased length some (all?) or make small removable grill plates for a more finished look.
Again, these will be big enough to warrant an internal mounting flange to double up the mounting thickness.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
The pipes in a removable baffle seems like a good, practical idea. Double thick panel would be good. Maybe make a flange ridge of single thickness around the edge of the removable plate for a better seal.
GM, do yo mean the bottom corners of the front baffle? As these are corner units, the ports have to be in front.
I think the 6" pvc would be pretty easy to do paint them black.But I would need 2-3 of them would I not to equal the port dims givin.
Anyway, looks like ~25 Hz Fb = 16.875" W x 3" H slot x 4" long vent and baffle thickness cutout = ~30 Hz, so this would be the minimum size cutout spaced up off the cab floor ~3".
And would the length still be the same 4" if say 3 tubes were used ?
According to his drawing, these stand proud of the corner 10" o.d., so while a rear offset with a ~6.62" dia. pipe would be a minimal difference between centered, best to have as much bulk in the bottom front corners to keep baffle mounting rigidity as high as practical.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
If you work out the pipe's cross sectional area (CSA), (2) 6" diameter pipes have a bit more CSA than (1) 8" diameter pipe, so one on each side panel is plenty and I'm hoping the extra acoustic mass loading of these short conic horns that the cab, floor plus two walls creates will reduce the longer calculated vent length to around 4", but they may need to be longer if a true 25 Hz tuning is desired.
Since the lowest note on a piano is 27.5 Hz though, this is all you need unless you decide to drive them with a very high output impedance amp which in this case will require tuning the cab to the mean of the two driver's actual Fs.
With these somewhat acoustically small cabs, any organ pipe symphonies with < 20 Hz output are best played with plugged vents and use EQ if necessary to flatten the system out.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
You are talking about the 10" side panels,as these are corner cabs i thought the vents are supposed to go on the front baffle at the bottom 3" from floor
Now I can put them on the side. There is no difference between front or side placement of vents? The actual part of the cab that will be going into the corner are just the 24" Triangular sides.But the ports if mounted in the 10" side panels will be firing essentially into/off the wall.a 25 Hz tuning would be sweet though that's what I will shot for ! Let me get this straigth to tune the cabinets lower I have to lengthen the vents correct ? Haven't had my pot of coffee yet so a little fuzzy ATM working on it though. :coffeedrinker:
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