Car Audio – Power over Quality
In search of the ultimate car audio system
Some scientific types believe that the walls of Jericho fell because of resonance. In a few years from now we are going to be seeing a lot of hearing loss amongst generation-Y and Millenials. Generation Baby Boomer may well be exempt except for the musician variety. Many musicians today suffer from tinnitus. The frightening aspect to all of this is that it can happen to anyone, especially those subject to loud music on a day to day basis. When wearing headphones on a day to day basis one would think that a feedback system would warn the user when dangerous SPLs are being generated but no.
Above: If this is what the Yellow Pages looks like after a few seconds imagine the guy’s cochlea.
The problem with headphones is that we do have a tendency to use them at a level which may not seem uncomfortable at first but will cause damage over a prolonged period. And one doesn’t know until one day you find yourself asking someone to repeat what they have said. Over and over again.
I touched on the subject of Jericho specifically because of the ease at which large structures can be made to resonate and cause untold damage. The human body can be broken down to various sub-parts each with it’s own resonance and the chest and surrounds are believed to be at that very frequency where our modern car audio culture is aiming – deep high powered bass. Okay, this is opinion only, I am not a scientist neither the most knowledgeable about the human anatomy. There has been research done in this field and it seems credible that high powered audio will not only damage your hearing but other parts of the body as well. In fact disintegration is highly likely.
Audio Outputs for auto sound
In the 70s car audio would in all likelihood be working around powers of about 4.5W RMS into a 4 Ohm load using our wonderful formula (Vcc * Vcc) / 8RL. Supply rails at 12V. At 13.8V we are looking at about 6W, 12W into a 2 Ohm load and 48W bridge tied into 2 Ohms. The thing is I don’t really recall many car audio systems being bridge tied until the 80s. 20W into 4 Ohms was more or less the norm and this was loud enough. Why then ramping the supply rails up to +40/-40V and into a 2 Ohm load? Marketing is a fairly reasonable assumption. Youngsters of today compare sound systems and the likelihood that they are making comparisons based on quality rather than raw power is negligible. Power is king.
Upholstery sound killer
Upholstery kills the high notes. We do not have a pre-emphasis feedback system which will crank these registers whilst applying attentuation to the bass. Listening to rap music at the traffic intersection is a case in point. Loud belching, farting, burping like sounds emanating from the car next to you is not uncommon. The thing is, and I mean this in all sincerity, what is it doing to you listening to that hellfire and brimstone spitting sound system? Having good acoustics is the first point of action.
Insane power levels
To Mom and Pop 10W per channel was more than sufficient and when they hit their 70s and if they were in good health their hearing mechanisms were usually intact.
New York band Manowar hit the SPL charts a few years back when they reportedly spewed out enough power to push dB meters to nearly 130dB. This is insane. Car audio enthusiasts see this as small puppy. Pushing levels to nearly 140dB at a few hundred Hz is common. And they drive playing at this level?
Our conversation level is usually at around 60dB, jackhammer at around 105dB and explosive power tools at around 120dB (nail guns). Ford Bronco with a 48kW sound system generating an SPL of 175dB? Utter madness.
Marketing the stuff
Ironically the best audio is found in luxury vehicles. Money spent on quality and not quantity.