When people buy a subwoofer to supplement their home theatre system, they expect their HT system to perform better, bringing their movie experience to the next level, and to have that oomph feel, instead, they get fart noises coming from the sub. My earlier comment may sound a bit childish but the port noise from a sub really sounds like farting noises. It is also quite loud which will get you up on your seat. It is a truly unpleasant and somewhat nerve-wracking experience which I have the displeasure of experiencing with my first HT setup. I thought I broke my sub just after a month of usage.
I understand how frustrating and disappointing it can be, but it is not the end of the line for your home audio system. I am going to share with you now the causes of having noises coming from the subwoofer’s port and what are the solutions.
What is Subwoofer Port Noise
So what are these heart-wrenching and annoying port noises coming from the subwoofer? These port noises are created when the subwoofer port could not handle the amount of air trying to be pushed in and out of the sub cabinet. It is also known as port chuffing and it can sound like a farting noise.
This usually happens during movie scenes with deep bass at high volume, this will most definitely disrupt your movie experience which I have first-hand experience with. In some cases, subwoofer port chuffing may happen even while you are listening to music. This issue can happen on quite a lot of ported subs and there are solutions.
Solutions to Port Noise Subwoofer
Turn down the gains
The most immediate way to rectify this will be to turn down the bass level and volume of the subwoofer so that air can be pushed in and out of the port smoothly. This will also mean your subwoofer will be softer than your desired loudness hence diminishing your movie experience. You can also try adjusting the crossover setting but to be honest, it may not be of help.
Relocate your subwoofer
If you prefer not to diminish your movie experience, then maybe you can reach a compromise with your sub. You should still lower down the gains, bass level, and volume of the subwoofer till there’s no more port chuffing. Then relocate your subwoofer, typically to the corner of the room where the back and side wall can reinforce the bass. Then test it out to see if the overall volume of the sub is what you want, you can also slowly turn up the gains. Try all 4 corners of the room, to see which location gives you your desired perceived subwoofer volume. If you do not wish to move the subwoofer around too much, you can use the subwoofer crawl method first to determine the best subwoofer location.
Another method will only be workable if you are using an AVR and has inbuilt calibrating software for example Audyssey. This will help calibrate your subwoofer to your main speakers. So when all your speakers are in sync and properly calibrated, it should greatly improve the sound quality overall. You can now try turning up the volume via the AVR, to see if the overall sound is good for you.
Change to a bigger port size – for DIYers
If you DIY your subwoofer then you can simply change to a bigger port size which will usually solve the problem unless it is not possible to increase the port length accordingly to the increment in size. You can also flare the ends of the port, which is another solution for DIYers.
Service your subwoofer
Sometimes, the noises you hear could be from other areas of the sub, probably a leaking subwoofer. If you think your subwoofer is damaged or defective, you should send it back to the manufacturer to have it service. The noises could even be from other places in your room. Let me give you a real-life example, I keep hearing rattling sounds whenever I am at a deep rumbling bass movie scene. The source of this rattling sound was actually coming from a wooden cabinet door near me, not my subwoofer.
Get a more powerful subwoofer
Sometimes in life, size does matter and is no different for the subwoofer’s performance. The larger the subwoofer the more air it could move, coupled with a powerful amplifier with high RMS and peak power, you got yourself a winner. But don’t just get the largest subwoofer you can lay your hands on. The craftsmanship and the quality of the subwoofer components are very important as well, in order to achieve high-quality subsonic performance. Another important factor will be how big is your listening area/room, no point in getting such a large bulky sub that will just overwhelm the whole room and kill off the rest of the frequencies.
There are downsides to getting a bigger and more powerful subwoofer. Firstly, it is going to cost you. Secondly, it is not easy to get the best performance from such a subwoofer. You will need to do the subwoofer crawl plus calibrate it with the right software either via the AVR (e.g. Audyssey Multeq and above) or from the sub manufacturer software (e.g. Digital Automatic Room Optimization from JL Audio).
Subwoofer Port Plugs
Some manufacturers will provide subwoofer or speaker port plugs along with the purchase of their products. You can plug them into your sub’s ports and this should prevent them from making port noises. Do note that it will tune the sub and will sound differently. Some subwoofers may not be suitable for port plugs, and you should check with the manufacturer first by contacting them.
Get a Sealed Subwoofer
This is the solution that I used myself to this day. Ever since my very first sub (ported) started chuffing and ruin my home movie experience, I told myself to get a sealed subwoofer next time. And I have not regretted that decision, no matter how hard I drive my subwoofer, it doesn’t clip and doesn’t have weird noises. I am using Ken Kreisel DXD-808, it is not cheap ($1995) for a sealed 8-inch sub but it is definitely worth the investment. I drove it so hard that my ears were in pain for a few hours (guess I was having too much fun).
The drawback for a sealed subwoofer is that for the same range, it will always have lesser bass output than a ported version but the bass will always be tighter and faster which is great for music playback.
Don’t be disheartened by this port noise, treat it as a lesson that will better help you to decide on your next subwoofer purchase. Like I always emphasize auditioning the audio components at your home first, especially the speakers and subwoofers, before making the decision to buy. This will greatly prevent bad buys and avoid port noises coming from your speakers/subs.