Fixing a Subwoofer: Repairing or Replacing a Home-Theater Subwoofer

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My first taste of home-subwoofer bliss was watching a movie in a friend’s home theater. The subwoofer pounded “pay-$20 bucks-for-Ticket-Popcorn-and-Drink” and brought meaning into the action scenes, adding oomph I never imagined possible at home. 10 years later, I have owned and experienced a variety of home-theater subwoofers of various brands such as Sunfire, Onkyo, Bose, Sony, Yamaha and repaired more than a few of my own.

Lets Verify Its Actually Your Subwoofer

Before we start, lets make sure we verify your subwoofer is actually the problem here. We will hit on how subwoofers work in a second but for now I would like turn on some music or a movie.

Take a listen and note what part of the song is missing. This might seem a bit obvious to you, but I’ve been asked to replace subwoofers due to the a lack of “crispness” in a system.

Since your subwoofer is responsible for low frequencies you should be listening for the rumble under the the punch. Another quick thing to do is take a look at the subwoofer while your playing audio to see if you get some movement. Touching it works too!

A long story short. If you are missing that low rumble from your audio and your woofer isn’t moving, its time to continue.

How Does A Home Theatre Subwoofer Work?

Let’s determine whether we can fix your old subwoofer by familiarizing ourselves with some principals about how the subwoofer works and looking at the parts that make a subwoofer. Then we can go through a quick and dirty checklist, and grab some tools.

All speakers do is convert electrical signals to sound. So the signal needs to get to the speaker. It’s Simple right? As for the speaker itself, it’s protected by a hard basket or frame holding it all together, Suspended just inside is a foam ring that remains pliable and able to move with the thrust of the speaker.

Just inside from this is the diaphragm or cone (Normally a more rigid material in the middle). In the center is a dust cap. This protects the voice coil from dust. Most Home Theater subwoofers are enclosed in a box. They may be powered by themselves or may be connected to an external amplifier.

How To Check To See If Your Subwoofer Is Working – Where Could the Issue Be?

1. Check all your connections to make sure they are nice and snug. Start with the back of your sub and trace wires back to the amplifier or radio. (use a flashlight) If you find a loose end, this is likely your problem. Congratulations… but why not keep reading just in case?

2. Check your power – Subwoofers often have switches and LED’s to indicate whether power is on

3. Check Volume and other dials to see if adjustments are needed. (Sadly I have done this myself. I tried everything to get my sound to work only to find that I had the wrong input selected) so refer to your Owner’s Manual to see if you have the correct settings.

4. If it just doesn’t turn on you should probably check first to see if your fuse needs replacing be sure to replace it with the same rating Fuse consult your owner’s manual.

Well if that’s all good it’s time to take a look at the speaker itself. It may be obvious right away that the rubber surround is ripped or worse. Did your beloved child or pet poke a hole in the speaker, it may not be the death of your subwoofer yet and if your sub is already dead what do you have to lose? Let’s play Dr. Subwoofer

Helpful Subwoofer Fixing Tips – Getting Down To Business

You need to decide now if you are comfortable taking your subwoofer apart. Well not right now! Finish reading this article. Almost everything can be done by anyone with a little patience and help. The help is there for the asking, most Speaker manufactures have Technicians who are happy to help you with the unique troubleshooting for your Sub. Vendors too are very helpful.

Fixing small holes in a cone:

Try to put some rubber cement on both sides of the hole for a quick repair then start to look into getting a cone replacement if that doesn’t do it for you.

Replacing the torn or damaged Foam Ring:

This really sounds more difficult than it is so, don’t stress.
In mine the steps went a little like this.

1. We need to carefully remove the old surround (be careful here not to rip or damage the cone if it is not already damaged, just take your time and get it as clean as possible, You will need to clean or remove the old material from the Cone Side and the Basket side.

Many find that a razor blade helps to remove things nicely; one tip would be to use the razor blade at an angle to the cone you will be able to clean the old material off easier and reduce the possibility of cutting into the cone.

2. Now we are getting ready to glue the new foam surround onto the inside edge. But before you go crazy with the glue give the new ring a nice dry fit to make sure it’s the correct size

3. Go ahead and take your new Foam ring and flip it onto its “face” side. Now you can start to apply the glue to the inside diameter of the speaker, if your kit came with glue most and most do. Go ahead and lay down a thin but stead bead of glue then take a small brush to spread the glue evenly. This will ensure a better bond.

4. Now do the same thing to the corresponding “CONE SIDE” edge.

5. Now go ahead and give it a little press all the way around the circumference to make sure the glue is going to adhere.

6. Now the Glue needs to be done for the outside edge. Start by laying a bee of glue on the basket side working the glue all the way around the edge and pressing the new foam ring on the Basket edge.

7. Give your speaker a few pushes checking to see if it is catching on anything.

Fixing a subwoofer

Well Congratulations you just rescued a possibly trash bound Subwoofer. You should really feel good about yourself. So how about a nice refreshing drink? It will give you a chance to let your nerves unwind and after the glue has set up you can start to break in the speaker. More on advanced subwoofer repair to come.