Subwoofer Information – Learn About Car Audio Subwoofers
subwoofers The bass. The loudness The glory. The most hateful component of your system, and also, one of the most necessary.
If you have read my article on loudspeakers, you are up to date. If you haven’t (and don’t know anything about speakers or subwoofers), read it here.
Subwoofers reproduce the lowest frequencies of the audio spectrum, also known as bass. They are essential to SQ and SPL systems, but for different reasons. Let’s take a look now…
For SQ systems: Effectively reproduces lower frequencies making music sound full and powerful. Instruments that play lower frequencies, such as organs, drums, and synthesizers, will sound more realistic and powerful with a subwoofer installed.
For SPL systems: Because subwoofers are loud, they are the preferred loudspeakers for making a lot of noise.
Also, because our ears are less sensitive to lower frequencies, we need extra bass to make the system sound balanced.
So what should I look for to find a great woofer? I’ll tell you!
Power management:
As with any other part of a stereo system, power handling is also important for subwoofers. Earlier in my article on speakers I talked about how you can send more power to them to increase their volume, but decrease distortion. The same goes for subwoofers, but beware! Since lower frequency distortion is harder to perceive, it’s easy to overdo and blow up subwoofers. Anyway, with that said, it’s smart to buy an amp that can produce exactly what your subwoofers are designed to receive, but take it slow!
Size:
Subwoofers come in many sizes, but the most common are 8″, 10″, 12″, and 15″. This was probably also noted in metrics for European brands. As you can imagine, the largest woofers are the ones that will play the loudest and the lowest. Of course, the smaller ones are more musical, more precise and sound more “tight”. The size you decide on usually has to do with your own preferences as well as installation considerations. Remember! 18″ subwoofers don’t fit anywhere!
Voice coil information:
SVC: Single Voice Coil
This means that the speaker has only one voice coil. In other words, just one entry.
DVC: Dual Voice Coil
This means that the speaker has two voice coils or two inputs.
Ummmmm, okay. Why does that matter?
I could go into detail here, but I know you don’t really care. Basically, it comes down to this: With a DVC subwoofer, there are more installation options. Look at it this way, a DVC “looks like” two subwoofers to your amplifier. With a few clever wiring tricks (called series and parallel), you can connect many subwoofers to a single amplifier, even if the amplifier is a “mono” or two-channel amplifier. Also, you can manipulate how many ohms the amp has to push. If you have an amp that is half ohm stable (like some old school Orion HCCA amps), you could run 4-8 woofers to a single channel! Imagine the noise you could make!
A few words about the boxes:
Enclosures are essential for most subwoofers. In other words, consider a subwoofer’s enclosure as important as the subwoofer itself. Why? Because most subwoofers need a box to work properly, sound good and not get damaged. Subwoofers that do not need an enclosure are called “free air” or “infinite baffle” subwoofers.
Like I said, most subwoofers need a box. So, let’s talk about boxes!
First, what types of boxes are there?
Sealed: The simplest type. Essentially, a sealed box is a box where the inside and outside are not linked. There are no holes and care is taken to ensure the box is completely sealed.
Ported: A ported box is a subwoofer box with at least one hole or “port”. The purpose of the led box is to emphasize a certain frequency. These boxes are used because they are often noisier than sealed boxes.
Bandpass – A bandpass box is similar to a ported box in that it has ports; however, the bandpass box attempts to de-emphasize certain frequencies, while emphasizing others. In other words, it works like a bandpass crossover. The bandpass box emphasizes a frequency band while de-emphasizing frequencies lower and higher than the band.
Isobarik – These boxes aim to fit more than one subwoofer in a small box. The subwoofers are configured to work in tandem. Sometimes both subs move in the same direction at the same time, sometimes one sub pulls while the other pushes. There are advantages to this type of configuration, but the design of the box is difficult.
Ok, now you know all about SUBZ, but here are the specs you’ll need to know to choose your subwoofer:
Power Handling: Subwoofers are speakers and as such can only handle so much power (or distortion) before they blow up! Power handling is measured in watts and is often given in two specifications: RMS and Max (or Peak). The RMS rating is the most important. If a subwoofer says it can handle 200 watts RMS and 400 watts Max, make sure the amp provides 200 watts RMS as well. Not 400 watts RMS. While it’s true that the subwoofer can handle 400 watts, it can only handle that kind of power for a short time. If you connect that subwoofer to an amp that puts out 400 watts RMS, you’ll ruin that speaker pretty quickly, because it’s constantly exposed to 400 watts, not short bursts of 400 watts. Do you dig? Okay.
Sensitivity: This term means exactly what you think it means. In short, a subwoofer with higher sensitivity will sound louder than a subwoofer with lower sensitivity when they are connected to the same amplifier. The specification is measured in dB.
Frequency Response – You obviously want a subwoofer that can handle a wide range of frequencies. However, the subwoofer works best below 100 Hz. If the subwoofer plays down to 20 Hz, you know you have a great subwoofer. The good news is that even if it doesn’t go down as low, most music doesn’t either. So, you’ll still be fine. I’d say it’s more important to have a low-end subwoofer in systems with DVD players and 5.1 sound. Also, the frequency response varies depending on the box in which the subwoofer is installed. Ummmm, so with that in mind, just go for a subwoofer that will handle power and sound the way you want it.
Cone Material – When it comes to subwoofers, this is a very important thing to pay attention to. Because subwoofers are big and powerful, you need a cone material that can take a lot of abuse. Personally, I’m a big fan of metals like aluminum. This is because aluminum is light and stiff, and likewise produces tight, musical-sounding bass. I know that many subwoofer manufacturers use exotic sounding materials for their subwoofers, which makes it difficult to determine which material is best.
Surround Material: Here’s my advice: always get a subwoofer with a rubber surround. Rubber holds up the best in the automotive environment.
Impedance – Measured in ohms, this spec tells you how much resistance the speaker presents to your amplifier. Too much, and you won’t get volume, too little, and your subwoofer will fry your amp! This spec will help you decide which amplifier to connect to your subwoofer, whether to link your amplifier together, and whether to connect multiple subwoofers in parallel or series. Also, subwoofers sometimes have more than one voice coil (also known as DVC). This means that the subwoofer will have two inputs, each with the same impedance. Dual voice coil subwoofers are more versatile to install, especially in multi-woofer systems.
The basic installation of a subwoofer is quite easy. If you buy a pre-made subwoofer box, mount the subwoofers and turn them on, you’ll get good bass. To professionally install and achieve the best sound, a lot of planning and work goes into the entire process. This is a situation where if you don’t feel confident in your ability to build a box, tune it and hook it up, you should visit a car audio store and ask them to do it for you. This can be relatively cheap or quite expensive.
If you plan to do the installation yourself, but do not have the skills to build boxes, you can buy a pre-made box. I would also highly recommend an equalizer device to fine tune the bass. This will help you overcome road noise (which ruins the bass) and will also reduce “rumble” and “muddiness”. In the end, this route is the best compromise between a custom box and a pre-made box. You’ll get great sound and save money!
Now be careful with those ears!
-Honest AEB