I’ve been asked to do a pictorial how-to about building kick panel pods,and the techniques outlined in here can be applied any one off fabrications of a similar kind.The beauty of this method is that if you are careful,you won’t need to use any body filler to make the curves,which is normally a very time consuming process.Because the fleece used will naturally make perfect curves when stretched over a former,this means that getting repeatable results when you need to make mirror image left and right pods or door builds is very easy.
I needed to make a pair of pods to take the soft dome mids and tweeters from my DLS Iridium 8.3 component set after the relatively easy job of mounting the 8in midbass drivers in the front doors using the lazy mans method of a pair of Autoleads off the peg adaptor rings (I keep promising myself I will make some proper ones from MDF or plywood when I get the chance).There are a number of reasons for mounting the mid and high frequency drivers as low as possible,the first one being that I really don’t like the sound of having them mounted anyhwhere near reflective surfaces such as the side windows or windscreen (to me this makes them sound unnaturally bright).The low mounting position also goes someway towards equalizing the path lengths (further helped by the time alignment built into the Pioneer DEH-9400MP head unit),and lastly to keep all the drive units as physically close as possible to each other (the overly large separation of the stock speakers produces two separate sources of sound),and to keep them as close as possible to being perfectly on axis to the listeners ears (in this case from the drivers seat).
It is necessary to mask much more than the area you intend to take a mould from as it can get very messy once you start splashing the resin about,and also it’s a good idea to put AT LEAST two layers of masking tape on,as it can find it’s way through the smallest of cracks or gaps in the tape.
I cut normal fiberglass matting into strips about 1in wide and assorted lengths from about 4in to 10in.
Mix up the resin according to the instructions,but not too much at any one time otherwise it will go off and be wasted before you use it all.Use a 2in or similar paintbrush to apply the resin to the area you need,plus a couple of inches overlap all round.I normally put some strips of matting around the outside of the area first to overlap the required area,and then fill it in to make up the first layer.Apply more resin using a stippling action until ALL the matting is fully wetted and has turned to the same colour.No real strength is needed with something like this,so I normally only do about three full layers of matting,each layer should be at right angles to the previous one.
Once it’s set properly (not too soon otherwise it’ll crack),you can peel the whole lot off ,the fiberglass,masking tape and newspaper all as one.
The masking materials can now be peeled off the fiberglass moulding,and trimmed roughly to size using tinsnips or a jigsaw (wear a mask when cutting fibreghlass with powertools).
The drivers are mounted on a 6mm MDF baffle board as close to each other as possible,with a raised trim piece around them.
They are glued and screwed together,and using hot melt glue and short lengths of wood to get the right angle to keep them on axis,and also making sure you have enough depth to actually fit them in.Once that is spot on,final trimming can take place to give nice smooth outline.
The baffles should be coated with resin before you cover them with the fleece,and then it’s simply a case of wrapping the fleece as tightly as possible around the whole structure,trimming roughly to size,and securing the loose ends with tape.It normally takes two or three coats of resin on the outside until it becomes solid,I then roughly cut the speaker holes out,and pour enough resin inside to coat all of the inside surface by swilling it around,the important bit is where the fleece meets the fiberglass moulding.
Once you can apply finger pressure,and can’t feel any real flexing in it anymore,then you don’t need anymore resin.When it’s fully set,you can finally trim all the excess fleece from the back,tidy up the area around the speaker cutouts,and start rubbing it down.I started with 60 grit ,as the texture of the resin soaked fleece is very rough to start with,and just keep going until the surface is as smooth as possible,It may need several coats of filler primer with more rubbing down with 600 grit in between to get it really smooth depending on how you did the applying the resin part of the job.
The reason for the two different colours of fleece is that I was trying different types out,the grey is heavier duty than the dark blue and can soak up a lot more resin,but I think that even for something this small,the grey gave better results.
Once they were nice and smooth,it was time for the final finish to be applied,and the only way I could get the really rough textured finish I wanted was to apply a few coats of Fleckstone paint first (who remembers the early 90s when we used to paint everything in our soundoff cars with it????),and then finish it off with a few coats of satin black paint.The Fleckstone really needs a few days to go off before covering it as it stays soft for ages and can chip very easily.
The pods were secured to the trim with a couple of short self tappers accessible through the speaker holes,being very careful of any wiring looms that run behind the trim panels.And finally the 75mm soft dome midrange and 28mm silk dome tweeter are screwed into place in the pods,and wired up to the amp and crossovers in the boot.The mids are driven straight from the amp and are bandpassed from about 500Hz to 1.5KHz,and the midbass and tweeters are highpassed from about 65Hz via their own passive crossover.
And the result of all this? A soundstage that seems to come from eye level,and seemingly has the musicians on top of the dashboard,and no identifiable point source of sound,and very smooth and natural sounding midrange and treble with good dynamics,only being let down by the very budget amplifier presently driving them,that will hopefully be changed for a JL audio 300/4 or Genesis equivalent when funds allow.
I hope all this helps,and gives inspiration where it’s needed,and if this does tempt anyone else to have a go,please let us see the results!
Chris.