"Crossover Design for New Project"

[SOOTSHE]

Better late than never

Tri-plex Bass Ultraflex

http://www.antiqueradios.com/archive...spkr_plans.pdf

Some fantastic vintage designs in there. Have definitely taken a copy for reference.
Thanks for sharing!!

[GM]

GM Have you had a chance to look at the port dims ?

Sorry, no, just now getting back to it and I thought I knew how thick the panels are going to be, but can't find it, so........ what's their finished thickness since your drawing dims are o.d.? Also, there's no base, right?

Did you decide to use the 1/6 and 3/5 driver pairings at least initially?

WRT to bracing, you ideally want them spaced at golden or acoustic ratios to keep each panel section from vibrating at the same frequencies, mostly defeating the point of using them, so I recommend putting one ~directly underneath the drivers and work out the spacing for any others.

That said, window braces look neat and work well, but impedes 1/4 WL pipe action in a high aspect ratio cab and since most of the cab's internal pressure is along its length, vertical board bracing is desirable and can be scrap no-void plywood, hardwood or HDF boards or similar, offset on the panels with some more boards tying them altogether like the window brace does to ensure the cab doesn't 'breathe'.

Got to finish patching up the roof's storm damage and fix a flat tire (body willing!) before I can get back to what's important in life, hobbies!

GM

[Altec Best]

[quote]

Sorry, no,

Bummer ! My cabs are being built as we speak so I will need them very soon at least an estimate i can have them cut short and tweak them later.When i get them home.

just now getting back to it and I thought I knew how thick the panels are going to be, but can't find it, so........ what's their finished thickness since your drawing dims are o.d.? Also, there's no base, right?

Thickness is 3/4" Baltic Birch ply with a applied veneer of 1/16" . Yes I plan on building a base for them, base is going to be 2" these cabinets will be on carpet so I want to mount furniture sliders on them as they will be very heavy and will make it much easier to move.

Did you decide to use the 1/6 and 3/5 driver pairings at least initially?

Yes I am !

WRT to bracing, you ideally want them spaced at golden or acoustic ratios to keep each panel section from vibrating at the same frequencies, mostly defeating the point of using them, so I recommend putting one ~directly underneath the drivers and work out the spacing for any others.

That said, window braces look neat and work well, but impedes 1/4 WL pipe action in a high aspect ratio cab and since most of the cab's internal pressure is along its length, vertical board bracing is desirable and can be scrap no-void plywood, hardwood or HDF boards or similar, offset on the panels with some more boards tying them altogether like the window brace does to ensure the cab doesn't 'breathe'.

Yes I was planing on using 2 window braces and tieing them all together from top of cab to the bottom,with some braces on edge on panels as well. Very stiff hopefully.But have decided to use single layer of plywoood (Window Braces) instead of the 3 layers initially.With the tieing them together with 2x3's should be extremely stiff.

:thankU: Again GM for your help it is much Appreciated !!!!!!!

Here's the veneer that has been stiched together for the front baffles starting to get an idea of what the Veneer will look like and I Like it Very Much.After a bunch of coats of Lacquer they will look saaweeet. :2thumbsup:


John

[GM]

[quote=Altec Best;1843058]

.........so I will need them very soon at least an estimate i can have them cut short and tweak them later.When i get them home.

Here's the veneer..........

OK, just to make sure, is the revised 54" height for the cab only or does it include the base?

Hmm, vents cut short? I guessing they won't be simple reflex holes. They will probably be multiple tubes or a single rectangular duct if you prefer the 'look' of a reflex vent. The tubes will be easier to shorten if need be though (longer = lower tuning, so this is where you start for in-room fine tuning).

Yes, they should be stunning!

GM

[Altec Best]

[quote]

OK, just to make sure, is the revised 54" height for the cab only or does it include the base?

54" is for cabinet only with the base it will be 56"

Hmm, vents cut short? I guessing they won't be simple reflex holes.

No they will be simple reflex holes,what I meant was I can widen the ports if need be.See they will be done by mid week so I will have to tell him what size to cut them.If I don't have the correct measurements I can tell him to cut them small and I can tweak when I get them home see when they are done I have to pick them up ASAP.

They will probably be multiple tubes or a single rectangular duct if you prefer the 'look' of a reflex vent. The tubes will be easier to shorten if need be though (longer = lower tuning, so this is where you start for in-room fine tuning).

I guess I would prefer a regular port,but if I use tubes to length the port are you saying that I can lower the tuning to say 25 Hz.At the moment I was shooting for 30Hz. What is the best course of action do you think ?

Yes, they should be stunning!
GM

Thank You ! Now if they sound as good as I know they will look then it will be all


John

[GM]

OK, I came up with ~18.56 ft^3 (~525.56 L) net which is about right for one driver tuned to ~30 Hz, so only ~half size for two, ergo raises F3 ~1.4x into the 40s, but corner loading hopefully will shift it back down a bit and with 107+ dB/sens/stereo +room/corner gain there's plenty for shelving EQ to flatten it out to Fb in-room.

Since the lowest Fs = 25 Hz, for now we'll assume it's the lowest tuning with the highest being ~40 Hz based on averaging everything out, though sealed is theoretically looking best overall if there's some half decent room gain.

You can use a rectangular duct vent, it's just more hassle to adjust its length and why I suggested a removable vent plate.

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".

GM

[Altec Best]

OK, I came up with ~18.56 ft^3 (~525.56 L) net which is about right for one driver tuned to ~30 Hz, so only ~half size for two, ergo raises F3 ~1.4x into the 40s, but corner loading hopefully will shift it back down a bit and with 107+ dB/sens/stereo +room/corner gain there's plenty for shelving EQ to flatten it out to Fb in-room.

Since the lowest Fs = 25 Hz, for now we'll assume it's the lowest tuning with the highest being ~40 Hz based on averaging everything out, though sealed is theoretically looking best overall if there's some half decent room gain.

You can use a rectangular duct vent, it's just more hassle to adjust its length and why I suggested a removable vent plate.

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".

GM

Ok Now I have something to work with !! Sounds Good Thanks GM !! John


:thankU: :thankU: :thankU: :lollipop::lollipop:

[GM]

You're welcome!

[Altec Best]

OK, I came up with ~18.56 ft^3 (~525.56 L) net which is about right for one driver tuned to ~30 Hz, so only ~half size for two, ergo raises F3 ~1.4x into the 40s, but corner loading hopefully will shift it back down a bit and with 107+ dB/sens/stereo +room/corner gain there's plenty for shelving EQ to flatten it out to Fb in-room.

Since the lowest Fs = 25 Hz, for now we'll assume it's the lowest tuning with the highest being ~40 Hz based on averaging everything out, though sealed is theoretically looking best overall if there's some half decent room gain.

You can use a rectangular duct vent, it's just more hassle to adjust its length and why I suggested a removable vent plate.

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".

GM

Are you saying vent length of Total 4" or with the baffle 3/4" + 4" Total 4.75" ? Please clarify.One other thing, I understand about the removable vent plate, but if it was going to be a utility gray i would have gone that route.But since I'm using a very nice veneer I think it looks better keeping the baffle all one piece.

Now would using round tubes be an option.I think they maybe easier to find in cardboard if tubes are used but i would need at least 4 at 3" diameter and 4" length correct ? I personally think the rectangular vent is better looking but would like to have options if I need some.

[Panomaniac]

Well I was thinking what you might do is have the vent hole cut 1.5" larger, then make several square tube vents of different lengths that you can put in there. Make the vent tubes of 3/4" material. Once you find the right length, have the small edge that shows veneered.

It's an idea, anyway.