Closer To Sonic Perfection With Up Front BassUsually I end this column with a question from you, the enthusiasts that are constantly striving to improve your sound systems. We're going to break up the routine this time and start with the question of the month. I'm doing this because I've noticed that many of you ask me the same question-how do I get the bass up front with the rest of the sound stage?
If you're like me, you notice a few things right away when you listen to a high-end car audio system. One of the first things I notice is where the bass is coming from. Surprisingly, many of the best systems out there still suffer from bass in the back seat. I don't know about you, but for me cars like this are hard to "buy into". Can you imagine yourself at a concert with the drummer or bass player in the back? Unless you're the singer, that's not what the real performance would sound like.
The reason so many cars sound like this is simple: it's tough to get the bass up front. Really deep bass often requires big speakers, and it's easier to fit those in the back of your car than in the front. If you're reading this column, you're probably not afraid of a challenge, so let's see what we can do to bring the bass up, so to speak, where it belongs.
Now, don't go ripping the four 15's out of your trunk just yet. You can do a lot with simple tuning. One odd thing about the human ear is its inability to detect low frequency location. Remember the last time you heard a sonic boom, or thunder? It's hard to pinpoint where it came from, unlike, say, a human voice. If the bass in your car is low enough in level and frequency, your ears probably won't be able to figure out the origin of the emanation (which is probably behind you if you have a typical system layout). Try lowering your subwoofer crossover point to 40 or 50 hertz, and see if it helps make it harder to locate. Make sure you don't have any rattles back there, because their higher frequencies will instantly "give away" where your subs are hiding. Also, it's important to have a high crossover slope (at least 24dB/octave) or else a lot of upper-bass will end up leaking through your crossover.
If you are trying this method, realize that you will need to have something in your system to create the upper bass frequencies that your subs no longer do. That "something" is usually a pair of midbass drivers in the front of your vehicle that can play cleanly down to 50 hertz. Fortunately, since you are probably running your front stage in the kick panels, you most likely have open door holes that will accept a reasonably sized midbass driver. If you can fit a 6.5" (or larger) driver in there, you can get good midbass in the front of your car. The key is to select the right driver and to install it properly. Demo your speaker candidates with punchy music to see if they can really produce snappy bass response. The installation must be very solid, so don't simply drop it into the factory hole and call it a day. The door must be reinforced with sound damping material so that it doesn't rattle or resonate, and the driver should be sealed into the door cavity to prevent cancellation.
Some of you are lucky enough to have very large kick panels; if so, they also make great locations for midbass drivers. A sealed enclosure usually works best in the kick panel, so more custom installation labor will be required. Just like subwoofers, the proper enclosure size is critical to optimum performance, so be sure to get this information from the manufacturer. There are some speakers out there that can actually produce great midbass and midrange, and this can really simplify your system if you choose to go this way. Whichever way you go, good up-front midbass with the correct subwoofer crossover settings will help give you the sensation of bass in the front.