back to fEARful
fEARful cutouts & gaskets
Cutouts with rough dimensions for spring-loaded handles are shown in many of the plans. The majority of the spring-loaded "rack-style" handles in the marketplace fit these 3" by 5" cutouts but you need to be aware that the corners should be radiused. The handles should be sealed with flat gaskets or sealed with gasket tape or a suitable caulk gasket. For smaller cabs it's best to stick with spring-loaded handles as they do not intrude on internal space for the woofer.
For larger cabs, cup handles can also be used; on some plans rough dimensions for these are also mentioned as an alternative. Again, there is some variance between manufacturers and it is not a bad idea to order handles FIRST and get measurements from the product before making cutouts for them. Again, suitable gasket sealing should be performed.
Also note that it is a lot easier to cut slightly undersized and then enlarge if necessary, than it is to make a hole that is too large fit the item tightly for a good seal. Often all it takes is a mild round-over at the surface of the panel to fully insert a handle that is a tad too tight for the cutout.
connector cup cutout
I specify these on the plans as 4" by 6" cutouts for a 5" by 7" part, so that if it becomes necessary at a later date one can reach inside the enclosure from the back to work with a spun-out T-Nut or Hurricane Nut, and can give access to crossover boards mounted higher up. Again, these holes should err toward undersized rather than sloppy as there is some variance between cups/plates that are nominally spec'd as 5" x 7" externally with 4" x 6" cutout. You should also radius the corners rather than doing a straight 90-degree cut. Also seal any jacks from the back side if possible. Most Speakons now are well-sealed already, but 1/4" jacks are real noise makers if they don't get sealed or plugged. I use only paralleled Speakons - which are better anyway - and thus avoid this problem altogther. If you can't remember a Speakon cable which is very distinctive in appearance, you need a checklist for gigging.
Again, dimensions for driver and waveguide cutouts are listed in the plans. And again, it is better to err on the side of "too small" and then adjust when beginning to mount the actual driver into the baffle than it is to cut out too much material. This is especially crucial with the Eminence Alpha or Alphalite 6A midrange drivers because they have their mounting holes very close to the edge of the cutout. Which means a hole that is slightly too large doesn't give much wood to bite into for the mounting screws, and also makes it imperative to be careful about getting a good seal for the driver.
The 6ND410 on the other hand will slip most of the way into a hole that is a bit too small, and to make it slip the rest of the way in often just some rasp work in four places where the driver's back frame cross-members are, or some round-over work there, which will allow it to slip the rest of the way in. It has its mounting screws further out on extended frame sections which is especially nice.
3012LF and 3015LF woofer cutouts are also pretty forgiving as the front frame lip is a lot wider so it's pretty easy to get a good seal. But if you cut too large it'll still give any screws or T-Nuts less to bite into, so don't go wide of the mark when cutting or routing for them. It appears the Eminence drivers now come with gaskets installed on the back of the frame lips but when I first designed the fEarfuls they were devoid of mounting gaskets.
Waveguide cutouts are pretty forgiving, but again: tight can be right, while too loose means you lose. Some waveguides come with gaskets, some do not.
The reason gaskets keep getting mentioned is that it is important for performance not to have air pressure escape routes anywhere but at the cone, and at the port. It not only degrades performance but also can lead to noises and vibrations. If you are doing a Tolex or "rat fur" carpet finish that will often be enough to supply a gasket seal at any cutout. Otherwise, any driver, waveguide, handle, or connector/crossover cup should be gasketed by one means or another for an airtight seal. Maybe the simplest general-purpose product that will deal with all of these instances is gasket tape.
back to fEARful