Improving the Mustang

The Ford Mustang GT, 5 litres of good honest, V8 muscle car.

The Mustang looks great from any angle and the rumble from that big lump up front is wonderful. Unfortunately the same can’t be said for the sound inside the car; the performance from the audio system is very weak. We recently worked on just such a car equipped with the Shaker audio system which, although fitted with an amplifier and subwoofer in the boot as standard, was distinctly lacking in performance.

As you may know I am an advocate of simple systems. The simpler they are the easier they are to control. Dozens of speakers does not automatically mean better performance where sound quality is concerned. A lower part count but of a better quality is much to be preferred.

The owner of the Mustang felt the same about the sound. After a discussion regarding his musical preferences he left the car with us for three days.

Choosing the system:

The first job was to assess the interior of the car for speaker and hardware locations and to listen to it to get a feel for the general acoustics both stationary and with the engine running. Try to work out where extraneous noise was coming from and gauge the sound stage from the seating position. The Mustang has six speaker locations in the front and two more on the rear deck; with an 8 inch sub in the boot. There is no spare wheel and the empty wheel well is spacious so ideal for amplifiers. There was also quite a lot of road noise in the cabin so we knew that a complete sound deadening treatment was required.

The audio performance for this car had to be spectacular, for me that meant A and AB class amplifiers for the main speakers with full active EQ control. I wanted detail and power in the front but also an all-encompassing performance from the whole cabin. I was instructed not to change any part of the car so that it could all be returned to standard so I knew I could only use an eight inch sub.

My choice of amplifiers had to be from the magnificent Audison Voce range.

I needed seven channels for a fully active system so that meant an AV5.1K and a Due. The beauty of the 5.1K is that channels 1 and 2 are full class A which is perfect to drive the tweeters. Channels 3 and 4 are class AB and ideal for the mid drivers. I had settled on the staggeringly accurate Rainbow Profi series for the front speakers and the Voce 5.1K would be the perfect partner. I opted not to install tweeters in the front A pillars as I felt they were too far forward to be of use and I knew I could tune the sound stage with the Audison Bit 1. This way all front speakers would be in the doors for the optimal imaging.

For the rear deck I chose the Hertz Mille Pro 165.3 coax. These are tight and punchy, perfect to complement the front detail. The Voce Due amplifier is very dynamic and again suits the performance I was looking for.

Since I was restricted to an 8 inch sub in the original enclosure I opted for the Hertz Mille Legend ML 2000.3. I have the same sub in my Discovery and know how much punch and performance this speaker can deliver. The 1000W from the sub stage of the Voce 5.1K amplifier will help as well!

Once the system had been decided upon it’s time to start work.

Initially we need to strip the car down to allow for cable runs and sound deadening treatment. This in itself can take a full day; as it is imperative that cable runs are safe and cannot cause rattles. A job like this requires a significant amount of cabling so we have to ensure that there is room under all the trim and all looms are protected and supported. Power cabling should be separate from any audio cabling where possible and of course carefully fed through grommets and sealed where passing through bulkheads.

Once I knew all the amplifiers and processor would fit in the wheel well I set about sound deadening the area.

This is made easier with all the trim panels out and will really help to reduce noise but will also improve the sub performance as no acoustic energy will be wasted into the resonant panels. Although the picture does not show it the treatment goes right up the side of the boot area onto the rear wing panels.

I also treated the rear deck as this can easily resonate with the extra energy we are generating in the speakers. I also built new wooden speaker collars to replace the standard plastic ones. This helps to isolate the speaker from the resonant metal deck.

Next Steps:

Once the rear treatment is complete I could start to manufacture the panels to support the hardware. Even though this can’t be seen I like to make this a perfect fit and trim it to look like the original.

This shot shows the initial setting up of the processor and amplifiers. This process tells the system where the input signal is coming from, what speakers are installed and allows me to set up the initial crossover points for the speakers, fine tuning will take place at the end of the install.

Now my attention turns to the front doors.

The Rainbow Profi speakers are quite simply stunning, their accuracy is very close to perfect so careful installation is essential. This of course means a full sound deadening treatment inside the doors as well as making wooden speaker collars and supports. Although not shown we also apply foam speaker rings around the mid and tweeter drivers. This helps to ensure an acoustic seal to the door card.

Great care is taken to ensure everything is moisture sealed to prevent any damp getting to the door card.

As I mentioned earlier, we were to use the original subwoofer enclosure to keep the car looking standard. This enclosure was manufactured from plastic so needed significant treatment to improve its acoustic properties. This was accomplished by lining the interior with copious amounts of sound deadening and adjusting the internal volume to suit the Hertz Mille Legend driver.

With all the trim panels back in place and a grille on the subwoofer the car looked almost standard. We did install the Bit 1 controller in the centre dash below the radio for convenience but even here the chrome finish and blue illumination looked perfect.

So how did it sound after tuning?

Well words can hardly do it justice. The image was high but surrounding with everything placing exactly where it should be. The sub was powerful without being obtrusive and a perfect blend with the front speakers. The Profi speakers benefit from an extended run in period but even initial performance was stunning. Playing my usual suite of test tracks demonstrated amazing clarity and detail; I use Eva Cassidy’s Fields Of Gold as a test piece and in this system her voice is sublime. This is one system I could listen to forever without any stress.

If you would like to know more about how we can improve the audio in your car please feel free to contact us on 01625 432707. Better still, call into our shop on Sunderland Street in Macclesfield. You’ll be glad you did!

 

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