How to Fix Speakers Placed Inside a Cabinet
It doesn’t matter the reason, but you have a cabinet where your TV lives. It might be custom, it might be a piece you bought years ago. But it is the TV’s spot and your speakers have to live there as well. If you bought home theater-specific furniture, there may be shelves that are designed to hold speakers. Most likely, this is not the case. At best, you have shelves that could contain a speaker but weren’t designed for it. What do you do? How does placing those speakers inside that cabinet affect the sound and is there a way to fix it? Well…
Sonically, This is a Bad Idea
As you probably expected, placing speakers inside a cabinet is usually a bad idea. We hope you have the foresight to realize that you shouldn’t close any doors while the speakers are meant to be playing. If you have, and you didn’t notice a change, then you have some serious hearing loss and should probably see a doctor. So, let’s assume that you put your speakers inside of a cabinet that has sides and a back. But not a front. Either that is because it literally doesn’t have a front or because you open the door when you use them.
If you as any manufacturer, they’ll almost universally tell you this is a bad idea. You really want to have some space around the speaker. This is because the soundwaves don’t just emanate from the front of the speaker and go forward. At high frequencies, this is somewhat the case. But as the frequencies get lower, the soundwaves start to wrap around the speaker. That means that the walls around the speaker will start reflecting the sound. This will muddy the speakers’ sound and sound strange.
Some of the waves will bounce and hit each other. Depending on how they hit, they may make certain frequencies louder or softer. You will also have waves arriving at your seat at different times. Instead of having a single wave arriving at your seat, you’ll have the wave that came from the speaker, and a number of other waves that also arrive. These will be from slightly different angles and delayed. This can confuse your ear (your brain, really) which will manifest as dialogue that is hard to understand, sounds that seem overly loud or soft, and general unintelligibility.
May the Universe Help you if you have a Speaker with a Port
If your speaker is ported, you are really in for trouble. The best-case situation is if the port is on the front of the speaker. Then, the port has all the problems that we described above. But if the port is on the back, the air escaping the port will be firing directly into a wall. It will bounce around the small enclosure until it escapes out the front. No one can predict how that will affect the sound. We do know that it is will be unlikely to sound correct.
Simple Fixes for a Speaker Placed in a Cabinet
The simplest fix is obviously not to do this. But speaker stands, mount them to the sides of your cabinet with a wall mount, or just put them on top rather than inside. Anything is better than placing your speakers inside a cabinet. But we’re guessing that isn’t an option. So, let’s go through a couple of quick fixes
Author’s Note: Some speakers, center channels in particular, are designed assuming that some users will place them in a cabinet. These speakers will have switches on the back to adjust the bass and treble to compensate for the expected problems such placements create. As the manufacturer has no want of knowing what your cabinet looks like or how it will affect the speaker, feel free to experiment with these. But don’t assume they will “fix” your in-cabinet speaker placement. We’d still recommend following all the steps below you can and THEN testing the different switch settings.
Fix 1: Pull the speaker as far forward as possible
When someone places a speaker inside a cabinet, it is likely because they don’t want to see the speaker. Their next move is to shove the speaker as far back as possible. This makes all the sonic problems so much worse. You want the speaker to be pulled as far forward as possible. If you can, the front of the speaker (not the grille, the speaker) should be in line with the front of the shelf they are sitting on. A little proud of that if you can get away with it. While this will not eliminate the sonic problems, it is a good first step.
If this is an open shelf, and you really don’t want to see the speaker, consider covering the opening with some speaker grille fabric. This fabric is acoustically transparent meaning it lets the sound through without affecting it. But it will block the speaker from view.
Fix 2: Plug ports
You’ll want to contact the speaker manufacturer before you do this one. To help counteract the negative effects of a rear-firing port, you could plug it. This will reduce the bass output of the speaker and could potentially damage the speaker. While you placed the speaker inside the cabinet for that clean look, you certainly don’t want to break it. The manufacturer will let you know if you can do this. The speaker design and how loud you generally listen will determine if this is a viable option.
Fix 3: Add insulation
If you can, fill the space around the speaker will insulation. While we often recommend rigid fiberglass or Rockwool, any insulation will work. More is better. This will reduce the volume of the soundwaves bouncing around the cabinet. If you have placed fabric over the front of the opening, then this should be fairly easy. Just fill up the space around and behind the speaker with as much insulation as you can. Remember, you don’t want to compress the insulation. Just place it in there.
Fix 4: Remove the Back of the Cabinet
Home theater specific furniture usually won’t have a back. There are a number of reasons for this including ventilation and access for wires. If the furniture you are using wasn’t made for home theater, it probably has a back. If possible, remove the back behind the speaker. This helps with the rear-port issue as well as gives the sound somewhere to go other than out the front. Of course, you’ll want to catch all the sound coming out the back before it gets back into the room. Place a nice, thick absorption panel back there. It’s behind the cabinet anyhow. No one will see it.
Fix 5: EQ
If you are a geek that loves numbers, you could fix this with EQ. You’ll still want to do all the things we said above, but you could take the next step and add EQ. You’d want to measure the response of the speaker in your room outside the cabinet and then placed inside the cabinet. You’ll add EQ that will make the in-cabinet placement sound more like the in-room response. This is higher-level stuff so we won’t go into detail here.
The real “fix” for placing your speakers inside a cabinet is to not do it in the first place. But if you must, you can mitigate the issues by following our steps above. If you’ve been living with speakers inside a cabinet and have been wondering if upgrading your speakers will fix the problems you’ve been having? The answer is no. Unless a speaker is specifically designed for in-cabinet placement, it is going to suffer from some or all of the problems above. Try our fixes before buying new speakers. You may find that your current speakers are just fine. They just needed a little help.