Sound System

The "sound system" for a 60's vintage Healey, or for that matter any other British car, of that era was generally an AM radio with a built-in 4" speaker.  I know, I had one in my 1959 100/6.  I got mine from Sears.  It was terrific fun to be cruising down the road on a warm summer evening and be tuned into a local rock station.  Then when they played a current Beatles' song, I'd crank up the volume and drink in the moment... life was good... college, beautiful girlfriend, and a big Healey.  Things have changed a bit in the world since then... one of which is the on-board listening experience.

To keep up with the times, the Sears AM radio has been replaced with a full function stereo with remote RF controller and a host of current high end features.  It sports 200w output (I think my Sears had about 5w peak) for its 4 channels.  To give it some muscle, I've added a 200w Alpine amp to pump it up to a total of 400w spread across 6 speakers in custom enclosures.  While the sound may not match an Aston Martin high end Bang & Olufsen sound system... it's pretty darn good.  So exactly what did I do to create this quality sound explosion in my AH?

I had a few packaging requirements.  Since I'm building a Works rally replica, I wanted to keep the interior looking functional... but upscale.  I didn't want the radio or speakers to be a prominent focal point in the car, and yet, I wanted a sound system worthy of a modern grand touring machine.  I'll be running with a factory hardtop, as the Works rally cars did, which gives me a bit of additional space in the back compartment.  Specifically, with the soft-top removed, I have the space normally occupied by the stored convertible top.  Additionally, since I built an electrical compartment (link), I had space to hide much of the electronics.  With those factors in play, I set about building a killer system.

The heart of the system is a Secretaudio SST (link) made by Custom Autosound.  Pic #1, 1b, 1c  It has a hideaway 200 Watt AM/FM CD tuner/amplifier/controller with USB port, direct iPod interface and much more.  A 10ft cord from the tuner/amp plugs into an LCD display.  It also features an "RF" (radio frequency) remote control.  The tuner can be placed anywhere within range of the 10' cord... which in a Healey means you can place the tuner anywhere you find a convenient place.  The LCD display, was the absolute most important element in this unit's arsenal of features that sold me.  It gives you total flexibility on your installation.  The fact that the display is only 1" deep means that your imagination is the only limiting factor in its mounting location... and with the RF remote, you don't even have to look at it if you don't want to!  Oh, yes, you will have to either convert your electrical system to a negative ground to use this stereo or you can purchase a Power Inverter from Custom Autosound to stay with your positive ground system.

I mounted the tuner in my electrical compartment.  Pic #2  Lacking an electrical compartment, you could mount it under the dash or behind the seats.  I have my under dash filled with A/C hardware, so that wasn't a good option for me.  Then place the LCD display in a location of your choosing... you've got 10' of cord to work with so play around with your options before you commit to the installation.  I put mine on the package tray.

Secretaudio provides a mounting bracket for the LCD, but I wanted something that integrated the display a bit more seamlessly with the surroundings.  To that end, I made a display housing that I then had powder coated in a black wrinkle finish to match the rest of the dash components.  Here is how I built it.

I've used the following methodology on a number of little projects.  It works well if you don't have a metal break, and it provides a very accurate sizing of the finished piece.  I started by mocking up the face plate in cardboard to the dimensions that I needed.  That got transferred to 1/4" steel templates (incorrectly labeled as 3/8" in the images).  I made two similar plates.  Then I rough cut a piece of 16 gauge steel larger than I knew I needed.  I sandwiched the 16g between the two 1/4" templates, drilled, and bolted it together.  The reason I use this approach is to keep the face of the display from warping when I hammer the edges over.  Pic #3,4

Then cut as shown and continue folding back all four sides.  Pic #5

This is what you should end up with.  Pic #6

The beauty of this technique is that you end up with all four edges nicely rounded and no distortion on the front surface.  I suppose it's a bit low tech but it certainly works.  As you can see from this image of the inside, Pic #7, the sides are not the same length.  I make no attempt to equalize them during this step... I'll do that later.

After removing the 1/4" steel templates, the insides of the corners were MIG welded.  Pic #8

Now cut the face of the housing to fit the LCD mounting bracket provided in the Secretaudio package.  Pic #9  I trial fit the LCD display to determine how deep the display housing needed to be.  With that determined, I put masking tape on the housing to mark where to trim.  Pic #10

I used a high speed cutter to trim along the line marked by the masking tape, followed by some work on a table belt sander to clean it up.  Tabs were MIG welded in to provide attachment points for the back cover and for mounting the display to the package tray.  Pic #11

The mounting tabs were tapped for 10/32 screws.  I cut an oversized piece of 16g for the backing plate.  After locating and drilling the holes to mount the backing plate, I trimmed it to fit... approaching it like this makes it easier to end up with a very tidy edge that closely fits the main housing.  Pic #12

The bespoke housing is held in place by a knurled knob which screws in through the package tray.  The reason I've attached it in this fashion serves a few purposes: 1) It swivels for easier viewing by the driver, 2) it can be easily removed for car shows, if I don't want the interior to look too high tech, or 3) I want to secure it when parked.  In any case, I like the flexibility of this arrangement.  The LCD display housing was then powder coated in black wrinkle finish... similar to the other items under the dash.  Pic #13

Now with the receiver and LCD display located, we can cover what, arguably, really makes this system better than I ever anticipated it would be.  On that note, I want to acknowledge my friend Ric Navarro.  Ric's day job is President of Home Electronics Professionals (link).  Ric, you may recall from other project papers, was the brain trust behind my EFI conversion... he's the guy leading/doing the overall wiring of this technical tour de-force.  Ric also knows a lot about sound systems... no surprise there.  But I digress; Ric guided me on the construction of the speaker enclosures.  Now there are speaker boxes and then there are speaker enclosures... these are the later.  First let's talk about the front speakers.

I'm using two Infinity Kappa Series 52.9i (5 1/4") speakers, these are the largest I could fit in the front. There isn't any magic to my speaker choice.  I went to a local audio stereo emporium and listened to a bunch and felt these gave very good price performance... so that's what I went with.  The front speakers are driven by the 200w Secretaudio tuner/amp.  The speaker enclosures are custom made 1/8" aluminum.  I mocked them up in cardboard and then worked under the dash to find the best place I could mount them given the restrictions imposed by the A/C system I have installed.  Once satisfied with where they would go, I had my local aluminum fabrication expert whip them up for me.  Pic #14  This shows the driver's side.  I've attached the housing to the air box and the steering column mount.


The key to the enclosures performance is the 1/2" port that spans from one side to within 1/2" of the other side and is vented to the outside.  The port, or reflex port, does more than what a simple hole in the side would do.  The port improves the low frequency response or overall efficiency as the speaker has to "work" to pump the air.  A simple hole in the side would cause the speaker to act as if there wasn't an enclosure and function as if it were in free air... that would reduce the low frequency sound.  Pic #15  As you can see, I've lined these enclosures with a fiber insulation and had the housing powder coated in black wrinkle finish.  When the enclosures are mounted all the holes are sealed... air can only enter through the port.

It would probably be better to mount the driver's side speaker vertically, rather than horizontally as I have, but the A/C ducting prevented that on my car.  If you don't have that area filled with something, I'd suggest mounting it vertically.  The passenger side speaker is mounted on the package tray, which is a natural.  Pic #16  My package tray has gone from a simple "tray" to a multifaceted technology facilitator with A/C ducting, power outlets, component plugs, heat isolators, etc., etc.

The rear speakers are a completely different animal.  As mentioned earlier, since my car will be configured with a factory hardtop, I could use the storage area normally used for the convertible top.  With a bit of fabrication, that became my rear speaker enclosure.  I used 1" oak for the speaker mounting surface and 1" pine in this image for the upright surfaces (these were later changed to oak).  Pic #17  I started out by mounting the 6x9's and then followed up with a pair of 5 1/4's... all speaker were sealed with foam to the oak.  Pic 17b

The metal area has been lined with Damplier Pro insulation by Second Skin (link); it's very similar to Dynamat.  Pic #18  I've used this insulation (Second Skin) throughout the car's interior, including the doors... with double layers on the engine facing surfaces.

After installing the rear speaker enclosure for the last time, the entire area is sealed using the silver aluminum tape used on the sound/heat insulation.  Pic #19  When the car is upholstered this area will get covered and the speakers will be rendered virtually invisible.  I didn't change any of the original top mounting brackets in building this enclosure.  If a future owner wants the original convertible top, this can be removed and the top reinstalled.  "No animals were harmed in the filming of this....." 

The speakers are two Infinity Kappa Series 52.9i (5 1/4") and two Infinity Reference Series 9602i (6"x9").  The rear speakers are driven exclusively by the 200w Alpine amp (MRP-F250).  The 6x9's are driven by the Alpine as low frequency (base), while the 5 1/4's are driven as mid-range.  The additional amp certainly improves the overall system.  While the 200w Alpine is a small amp, I felt that given the size of the car it would be more than adequate... I'd say that has shown to be true.  If you can't fit another amp, I suspect that the Secretaudio's output would still be a significant improvement over most systems currently in Healeys

So from the driver's seat this is what I'm looking at... Pic #20

The sound system has exceeded my expectations.  As I said, it's not a true high end system, but it certainly has impressed me and the folks I've forced to preview it with me.  I have been putting my CD's on USB Flash Drives (memory sticks (loaded in MP3 format))... a 2 gig stick will hold up to 40 hours of music.  The tuner handles it like a CD changer.  Pop a flash drive (memory stick) loaded with your favorites into the handy USB plug-in on the package tray, and you are good to go!  Of course, if you are an iPod person, you can plug it into the iPod cable also located on the package tray.

So the Sears AM radio has been superseded.  Life in the world of sound systems has changed forever... not all changes are bad... in fact, I kinda like personalization.

Oh, and by the way, the young lady sitting beside me in the AH 100/6, in the aforementioned run down memory lane, will be my copilot in this AH 3000... 42ish years later and some things don't need to change! 

Steve Thomton

This project paper was first posted on April 28, 2010.