Constraints & Requirements:
This is one of the most important aspects to a mobile audio install. It is important to understand the environment you're working with and its specific acoustic challenges before you dive head-first into mobile audio. One of the biggest mistakes people make in mobile audio, and a mentality that is perpetrated by much of the mobile audio industry, is that you can get better results by just throwing more money at it. While there is some ray of truth to getting better results by using better components, everything has to be used correctly.
Since audio installs tend to be highly subjective with a great deal of brand bias/loyalty, it's important to establish the constraints around which this system was designed and built. Without constraints and requirements, we don't have an objective manner in which to design the system. With constraints and requirements clearly defined, we can narrow down our options. Here are the constraints and requirements I've set for this showcase project:
Space: This is the most obvious of our constraints. The car is small, so the components used will have to be as well. Multiple considerations will be made for component location, which may involve some unusual and unconventional install locations for components. This will inevitably make install more difficult, but will better utilize already extremely limited space. Folks, it doesn't get much more limited than this. Despite this limitation, the goal is for this system to not take away any functional space from the interior or storage of this vehicle. Every effort possible will be made so that the trunk, storage compartments, and interior space will remain the same as stock.
Budget: As I noted before, this isn't a Ferrari, so I will not be installing Focal or Morel speakers, Hertz amplifiers, or Audison digital processors. That's not to say you can't get good results with those, it's simply difficult to justify components of that caliber with my budget and the noise floor we have to deal with. I am setting a target budget of $1,200 USD for this project. .
Noise Floor: Because this is a convertible, no matter what you do, the car will not be suitable for ultimate sound quality. That being said, sound quality is not the only goal of an upgraded system. Most people following this thread will be looking for louder and less fatiguing sound under top down driving conditions, as well as clearer sound with the top up. We won't be chasing every last bit of distortion away, and I won't be spending money on high dollar amplifiers to get rid of that last 0.1% THD. You're more than welcome to your adaptation of this build, but I don't feel that the extra cost of high end amplifiers justifies the comparably minor sound quality improvement. This will make it easier on our budget while also allowing us to set reasonable expectations. I'm going for loud and clear with low fatigue.
Complexity: Because we have some pressing constraints, that increases the complexity of our install. This is more of a compromise than a constraint, but it goes without saying that this will not be as simple as in larger vehicles. For example, while I might be able to get away with more easy to use drivers like I did in my Cruze, this car may require some unconventional approaches to driver choices. That being said, I am setting a requirement for simplicity.
Because I want world-class sound to be accessible to everyone, I will make the following efforts to reduce complexity:
- I will be doing all of the tuning for free. That means I will spend several hours in my car with a measurement microphone precisely tuning the in-cab response, adjusting crossover with 3rd order harmonic distortion, and setting time alignment so all you have to do is download the file, upload it to the DSP, and hook it all up. The only drawback to this approach is that the tune will be specific to the speaker drivers I end up using.
- I will only use a 5-channel amplifier in order to eliminate wiring and reduce component cost.
- I will provide a power cable kit with hydraulic terminal crimps specifically measured for the 124 Spider's cabin so all you have to do is run the cable, hook it up, and you're done. You'll have good, true AWG OFC cable for power and ground with proper crimps.
- I will use factory integration wiring to effectively eliminate any cutting or splicing of factory wiring and allow you to revert the entire car back to stock without any trace of anything having ever been done.
I don't like splicing into wiring; it damages the casing and exposes it to corrosion long-term. As a result, I have spent hours of research finding factory integration modules. As a result of these efforts, if everything fits according to plan, there will be no need to cut or splice any factory wiring, resulting in a clean, easy install that anyone can do on their own.
LFE (Low Frequency Extension): Basically, bass; how low can you go? Not that we need earth-shaking bass that can be felt from a block away, but we do need tonal accuracy and the capability of the lower frequencies to keep up at louder volumes. For that, we need a subwoofer, and this system will have a subwoofer! I have not decided if it will be an 8" or a 10". I am 90% confident that we can fit a 10" sub, without using the trunk or any cabin space that is currently available for driver or passenger.
We're not just going to slap a pair of component speakers in and call it good. I have a level of sound quality that I won't compromise on. This system will include time alignment, frequency response tuning, and precisely measured crossover slopes to allow the best sound stage this car can possibly have.
Nothing says "rob me" more than fancy high dollar equipment that you can see plain as day. We will build everything into this car in hidden or factory locations so you won't even be able to tell anything has done, aside from the preset controller on the DSP.
Last edited by XtremeRevolution; 02-11-2019 at 05:30 PM.