If you’ve ever taken any interest in subwoofers, you’ve probably heard the term “Subwoofer Break In”. Additionally, if you frequent any of the popular car audio forums, you’ll notice that more and more people are asking about the importance of a good break in. Is it mandatory? How long should a break-in period last? Does breaking in your subs improve sound quality or is it just a myth doing rounds in the audio forums? What can happen if you skip breaking in your subs? Is there an appreciative difference in performance pre- and post-break in?
These are just but a few questions that most people ask when it comes breaking in subs. These questions need proper answers in order to demystify and assess the efficiency and the effectiveness of subwoofer breaking in.
So, let’s get it to it…
What is subwoofer break in?
Breaking in a subwoofer means playing the subwoofer without pushing it hard for a certain period of time for the purpose of ultimately loosening the unit’s suspension and improving performance.
Breaking in a subwoofer takes time and patience; The most common break-in practices recommended by subwoofers manufacturers include gentle playing, avoiding pushing the subwoofer hard, and always increase volume gradually.
Why breaking in a subwoofer is important?
To prevent their cones from falling apart under heavy load, subwoofers use heavy duty suspension that’s strong enough to mechanically handle outrageous amount power on continuous basis. Out of the box, the mechanical parts that the subwoofer consists of – especially the spider and cone surround – are really tight and stiff.
The spider of a subwoofer (also known as the damper) controls the cone’s movement and keeps the voice coil centered in the air gap. The spider acts like a suspension or shock absorber, smoothing out the cone’s ride.
Most car subwoofers have elastic deformation or “low compliance” that require a break-in period to gradually loosen the stiff spiders (suspension), thereby ensuring higher excursion and allowing the subwoofer to dig deep into the lower frequencies.
As the subwoofer is being played, the resins in its spider begin soften and partially break apart. The woven poly-cotton fibers that compose the spiders begin to loosen and stretch out, and as the cone is vibrating, its surround become more pliant. That’s why you need to give your subwoofer some time. It’ll eventually play louder and lower as it breaks in.
During the break-in period, not only are the suspension and the surround softening up a bit, but that softening is also causing a shift in the electro-mechanical parameters of the subwoofer. And if you’re familiar with T/S parameters (which define the specified low frequency performance of a subwoofer), you’ll notice significant shifts in the free-air resonance (FS) of your sub as much as 10-20%.
With all of that being said, think of breaking in a subwoofer as a freshly built car engine. After the first oil change, gas mileage and performance increase. It’s the same concept with subwoofers.
Most often, a subwoofer that underwent a long break in period will easily last beyond its intended lifespan, compared to a subwoofer that was never broken in.
How to properly break in a subwoofer?
There are two efficient ways to break in a subwoofer. Before we get into them, it’s worth mentioning that maintaining a steady power load on your subwoofer during the break-in period is highly recommended. Additionally, keep in mind that music tracks with intermittent bass rumble won’t do the trick. What you need is some continual bass heavy music played at a low volume.
We’ll start off with the easiest way which is the most common and widely used method, and that is to simply mount the subwoofer as you normally would. Next, keep playing your favorite tracks at low to medium volume a couple of weeks.
As the days go by, the suspension of your subwoofer will become more flexible and its Fs (Driver free air resonance, in Hz) will drop, allowing your subwoofer to play louder and hit low frequencies with less power.
A few weeks down the road, you can set your gains accordingly and listen at normal levels.
This method does require some nifty tools and isn’t as straight-forward as the first one. However, it yields much faster results.
In this method, the subwoofer is mounted outside the enclosure — free-air setup (aka: Infinite baffle) — before installing it in its designated enclosure.
You’ll need the following:
- A tone generator app (can be downloaded from PlayStore, or Google Play).
- An external amplifier
- 3.5 mm jack to RCA so you can connect your phone directly to your amp.
- A board or mounting surface (called a “baffle”). This can be a flat piece of wood with your subwoofer mounted to it. Put it between two chairs or tables, and make sure you weigh the sides down so it won’t move.
- Now that the subwoofer is mounted to the board, you can begin the break-in process. Use the tone generator on your smartphone to play a 40 Hz tone for about 15-20 hours. You can set it with a good clean signal overnight. Once this is done, you can mount your sub in its box.
What can happen if you skip breaking in your subs?
If you push a brand new subwoofer hard from day one, you could run into either a burned coil or a ripped suspension.
- Burned Coil: Stiff spiders means less suspension which in turn means low cone excursion. This coupled with excessive power causes the coil to heat up very quickly in the gap as it cannot move enough to shunt heat away. With excessive heat build-up comes the increased risk of burning the voice coils.
- Ripped or torn suspension: Pushing your subwoofer from the get go will put a lot of strain on your sub’s mechanical part. Hence, you risk tearing the suspension from the basket causing mechanical failure.
Not properly breaking in a subwoofer means two things: a lot of distortion and much shorter lifespan.