Car audio really is a science, but for most of us, science is something best left in the classroom. However, there are some real dos and don'ts to a good car audio system. For whatever reason, despite our best attempts to stamp them out, the don'ts always seem to live on, like the cockroach.
So we thought we'd tell you about some of the most common misconceptions we come across when reading your e-mails and letters (and when talking with people when they let us out of our cages). To make sure we're not just blowing smoke, we contacted three experts in their fields and asked them to debunk these myths and put everyone on the right track.
Speaker PlacementThis is probably one of the most sensitive subjects and everyone seems to be an expert. Speakers come in all shapes and sizes and the OEMs stick them everywhere, sometimes in really crummy places.
Guys, let's start with tweeters. Where's the best place to put one? We've seen them high on an A-pillar, at the top of the door, in the dash, in front of the mid, in kickpanels, you name it.
Mark: For me, most of the time, it's right next to the midrange. You've got the two speakers; you want to keep the wave front coherent between the midrange and the tweeter. And that doesn't always mean move the mid up to the tweeter because you've got so many reflective things up high. But if you mount them down low, like in a kick panel, sometimes you can add a second tweeter up high and add a little salt and pepper to the high-frequency range without affecting the overall wave front. If you do that, it should have a higher crossover frequency like 8[kHz] to 10,000Hz.
What if your stock door panel has the tweeter high in the door or in the dash and there's no place to put the tweeter by the mid? Is it worth paying extra for a custom mount or something to put the tweeter next to the mid?
Mark: Well, that's kind of a can of worms. The midrange in the bottom of the door is a compromise compared to the midrange in the kick panel and the tweeter compromises it even more. With the kick panel, the path lengths are so much closer to equal, but you never see this from the factory. The guys that make the cars do seats, the dash, the doors, the steering and all that, and then they give it to the stereo guys and say, "You can put your stuff here." But, doing that (mounting the tweeter next to the mid) is no guarantee. It comes down to the experience of the installer and making sure that it sounds good. Maybe he's done it before and it turns out that the set of components you're buying were designed to be mounted apart. Maybe there's a setting in the crossover for high or low on the door. Just because the guy puts it down there doesn't mean it's going to sound good. A lot of times, if you don't do other things correctly, it might make it sound worse. It comes down to the installer.
We need to pin you down here. You're saying speaker placement is critical in every system and you say the best place for the tweeter is close to the mid to make the wave front coherent. But it's not an always thing?
Mark: Man, we're getting into territory that, ah ... I teach a sound quality course that's five days, and we spend a day and half, almost two days, just on speaker placement on how to handle different situations like that. And that's in person with demos and test gear and hands-on stuff. How about this: In general, you're going to be better keeping the tweeter next to the midrange.
SubwoofersOK, that horse is dead. Let's say keep it close, but always listen and don't be afraid to experiment. So how about woofers? Again, everyone knows everything about woofers. One of the most common myths is that the larger the woofer, the "slower" it sounds. What is this? How can a woofer be slow or fast?
Garry: I love this one. I hear it all the time. The reason that whole thing got started was back in home audio there were a bunch of sealed box systems and the boxes were being built too small. That made the sound really boomy and people would blame it on the woofer's size. Well, no, it's because that woofer's not in a 6ft3 box like it needs. You can have 15s that sound very tight and fast or you can have 10s that play very low with good output. The whole object of the game with loudspeakers is air displacement. It's done two ways: either with diameter or excursion. You can take a smaller speaker with more excursion and it will actually play lower and louder than a larger speaker with less excursion.