When designing a car audio subwoofer system, the Product Specialist and Installer you’re working with have two options for mounting subwoofers in your enclosure. There is, of course, the typical method with the motor assembly and basket inside the enclosure. With that said, many installations have the subwoofers mounted upside down, or as many call it, in an inverted fashion. There are benefits and drawbacks to this installation method – let’s talk about it!
Benefits of Inverted Subwoofer Installation
The most significant benefit of having your subwoofers installed such that the motor assembly and basket are visible is cooling. The heat generated in and around the voice coil and magnet can easily escape into the air in the vehicle. Access to all the relatively cool air in the vehicle can dramatically improve thermal power handling, especially compared to an acoustic suspension (sealed) enclosure.
The second benefit of an inverted subwoofer installation is mounting depth. With only the cone inside the enclosure, you can install deep subwoofers in locations with minimal mounting depth. Yes, you’ll have a large woofer protruding from the enclosure’s front, which may affect your vehicle’s cargo carrying capacity.
Extending this same philosophy regarding depth, another small benefit of inverted subwoofer installations is increased enclosure volume. Subwoofers with large baskets and motor assemblies can easily displace 1/10th of a cubic foot. Thus, your installer can reduce the size of the enclosure or use that extra airspace to improve the low-frequency output of the subwoofer system. The difference isn’t likely to be dramatic, but more deep bass is always a good thing!
Drawbacks of Having Your Subwoofers Upside Down
There are some drawbacks to inverted subwoofer installations. First, it’s challenging to protect the rear of the subwoofer and the wiring from damage caused by cargo. This isn’t the sort of installation you’d choose for a daily driver that’s also used to get groceries or go on vacation. On the other hand, it might be great for a company demo vehicle or a show car where there’s a conscious and consistent effort to keep things safe.
It can be tricky to come up with a way to keep the wiring to the subwoofer’s voice coils looking tidy. Inside an enclosure, so long as the electrical connections are solid, few care how the wiring looks. When the wiring is visible, then terminations and wire routing become a genuine consideration. Protecting those connections from damage or from objects that might short the terminals is also an issue.
The next drawback is a minor reduction in efficiency. No, the operation of the subwoofer doesn’t change, but the effective cone area might be reduced. When the woofer is mounted conventionally, you have the entire cone surface available to pressurize and rarefy the air in the vehicle. When mounted upside down, the area of the cone inside the voice coil may not contribute to moving air. This effect depends somewhat on the design of the woofer. If there’s a vented pole piece, the change will be minimal.
Lastly, and perhaps the most significant drawback of having a subwoofer mounted in an inverted fashion, is the chance for unwanted noise. Not all voice coil cooling systems are quiet at high excursion levels. Airflow around the coil, top plate and in and out of vents may add unwanted huffing and chuff at high output levels. There is also a chance that tinsel leads can make noises if they come into contact with the cone when played loudly. Unfortunately, if you have a subwoofer that makes these kinds of noises, there’s typically no easy way to remedy the issue. It’s best to mount those subs in a conventional cone-out installation. Your installer can test the subwoofers by applying a signal to them and listening for noise without any enclosure. Be careful not to bottom out the woofer, though.
Balance the Benefits and Drawbacks
As you can see from the images we’ve included in this article, sometimes the only option is to mount the subwoofers such that the motor assembly and basket are visible. You can discuss your inverted subwoofer installation options with the installer before work begins on your car or truck to ensure that you’ll be happy with the results.
Lead-in Image: Thanks to Matt Schaeffer from Musaic Audiophile Design in Lewes, Delaware, for sharing this installation of a pair of Focal subwoofers in the back of a ZL1 Camaro.