How to Set Up and Calibrate a Subwoofer
This article is part of our Home Theater Design Series that goes over almost everything about designing a home theater.
Adding a subwoofer to your home stereo system or home theater system can make a huge improvement in your sound if you know how to properly position the subwoofer and adjust all of the settings. If you are willing to spend just a little bit of time learning how to set up a subwoofer the right way, the addition can transform your system. You might get lucky if you just plop it down, turn it on, and everything winds up perfect, but odds are you’ll need to play around with placement and adjustments to get ideal results.
The main reason people add a subwoofer is the obvious one: you will normally get deeper, and more, bass output. What you may not realize, however, is that adding a subwoofer can also improve the midrange and treble definition of your main speakers. Although, there is a risk of a sub addition making your main speakers sound worse if you just drop one in without some tuning.
Where you sit and where you place your subwoofer will have a tremendous impact on the ultimate sound. If you have not read our article on subwoofer placement, please read that first before proceeding to the steps we describe next. This article is all about how to properly set up and calibrate your subwoofer once you have it generally placed in your home theater.
With home theaters becoming so popular, and great bass being an essential part of it, you will notice there are a large variety of subwoofers on the market to choose from. At one extreme are basic models with simple connections and at the other are subwoofers with complete room correction built-in and even some have an app to help you fine-tune your subwoofer from your listening chair! We will go over how the setup process applies to the different types of subwoofers out there.
First, there are some basic things about connecting up your subwoofer(s) you should do first before you start any listening tests.
Connection & Setup Considerations
Wiring and Connecting
Every home theater receiver or processor has one or more subwoofer output jacks on the rear panel. You want to use an RCA cable to run from the subwoofer out on your receiver to your subwoofer. If you have two subwoofers, it is great if your receiver has two subwoofer outputs, but you can still get the benefit of two subs with just one sub out on your receiver. Simply use a high-quality “Y” connector to split the signal and run two cables from there. Most subwoofers also have left and right input. For home theater, you do not have to worry about this and can just connect to either one. The only exception would be if your sub has one of them labeled “LFE”, in which case you would use that connection.
A few subwoofers have both input and output connections. Please confirm you are connecting to the ones labeled input.
While you are behind your subwoofer, you will probably see it has a knob for level control. For most subs, just set this at about 12 o'clock. Also if your subwoofer has a phase switch or dial, set it to zero.
Avoid Double Crossovers
Another thing that is critical is to make sure you are not using two crossovers. The crossover is the electronic circuit that sends the low bass tones to the subwoofer and the rest of the sounds to your other speakers.
Almost all home theater receivers have subwoofer crossovers built-in and also most subwoofers have a crossover on the back of the subwoofer. These allow you to set the crossover frequency where the division between the subwoofer and your other speakers takes place. You do not want to accidentally cross things over twice.
We find it best to use the crossover in your home theater receiver and bypass the crossover at the subwoofer. Make sure you connect to the bypass input on your subwoofer. Some subwoofers will have two sets of inputs with one labeled bypass and the other labeled crossover. Others will have just one set of inputs with a small toggle switch where you select bypass or crossover.
Home Theater Receiver or Processor Setup
Before you start listening, you will also want to make sure your settings are correct on your home theater receiver or processor. Your receiver will have a section in the menu where you can tell the system if you have a subwoofer and where you want to cross it over. Obviously, you want to tell your receiver you are using a subwoofer. You then will normally have a choice of where to set the crossover on all of the speakers in your system. Some receivers give you a choice of large or small, where others give you frequency settings. It is best to start out with all of your speakers set to small or if you have frequency adjustments, set them all to 80 Hz.
The next step is to make sure your distances are entered into your home theater receiver. Use a tape measure to find the distance each speaker is from your main listening spot and enter that into the settings. We may change these later for the subwoofer, but for now, use what you measure.
Critical Tech Tip: If your subwoofer comes with a microphone and/or has an app or is wireless, it has digital processing inside that will delay the signal coming out of the subwoofer. Most subwoofers like this have a delay of anywhere from 8 to 12 milliseconds. A millisecond translates into about 1 foot of distance. This means you will need to add, on average 10 feet, to your distance setting at this stage before you start listening to better align the signals reaching your ears from your subwoofer and main speakers. This only applies to subwoofers with room eq built-in, app control, or are wireless. We will go over how to fine-tune this distance in the phase setup.
The last step is to do a rough level settings adjustment. There are a variety of decent apps on the market for smartphones that will let you measure SPL (sound pressure level). You can easily download one on your iOS or Android device. We like SPL Meter from Studio 6. Turn the test tones on and match the levels up using the meter on your phone. In most cases, you will set the levels of all speakers to 75db. If you have multiple subs, for each additional sub, set your level about 3db lower since they will combine to about 75db (e.g. if you have two subs start by setting each at 72db).
Tech Tip: Remove the cover on your phone if you have one, flip your phone over and point it straight up when you are measuring levels.
Listening Adjustments for Subwoofer Placement
If you have not read our article on subwoofer placement please do so before proceeding with the next step. You want to first place your subwoofer or subwoofers in the best spots possible in the room and then move on to sub EQ calibration below.
Subwoofer EQ Calibration
If you are lucky enough to have a subwoofer with auto-calibration, it is now time to do that step. There will be instructions that come with your subwoofer on how to do this. Normally there will be a calibrated microphone and stand you will connect up either to a computer or the subwoofer. Just follow the steps and let the subwoofer calibration do its thing.
Note: There are a few subwoofers on the market that have manual room eq on the rear of the subwoofer. To use these, you will need some more advanced audio tools as you will need to know at what frequency the peaks are occurring in your room. Room EQ Wizard is a good one, but you will also need to purchase a good USB microphone. You will play some test tones through the subwoofer to visually see the peaks, then try to take them down by reducing the same or a close frequency on the back of the subwoofer. We do not suggest you try to take out dips by boosting the EQ controls on the rear. Trying a different position in the room for the subwoofer is a better idea.
For those of you with subwoofers that have no calibration feature, you will skip the calibration step.
Subwoofer Phase Adjustment
For the best experience, we want the sound from our main speakers and subwoofer to arrive at our ears at the same time. This is what phase adjustments can do. This adjustment is a bit geeky and you can skip it if you are more of a casual listener. However, when you do get the phase-matched between your subs and main speakers you get this sense of effortless sound that is pretty amazing.
There are a small handful of subwoofers on the market that give you the ability to adjust the phase from 0 to 180 with everything in between either with a knob on the rear of the sub or an app that allows you to do the adjustments.
Changing the distance in your receiver will also adjust the phase, which is what will be more common for most home theaters. Some subs have the phase knob (which adds delay) whereas others use an app--using a phone app allows you to change the phase from your seat which is generally easier.
We actually find it easiest to just change the distance in your home theater receiver or processor.
First, you will need to get a test tone to do this with. You can use this youtube link for a good long 80hz test tone that can play while you run your test. If you set your crossover with your main speakers to something other than 80hz, then use a YouTube test tone that matches your crossover frequency as our goal is to match the phase of our main speakers and subwoofers where they are both playing the same frequency.
Room With One Subwoofer
Set your home theater receiver or processor to play stereo.
Now sit in your primary chair and start up the test tones. Make a note of the SPL you are getting. Then slowly increase the distance in 1ft increments and stop where you get the highest SPL measurement. If your subwoofer does not have digital processing the maximum SPL will likely be at approximately the actual distance from the subwoofer. If your subwoofer has digital processing, the SPL will be highest somewhere between the actual distance and about 12 feet extra which would correlate with a 12-millisecond delay.
You are done.
Room With Two Subwoofers
For two subwoofers, the process will depend on your home theater receiver or processor.
There are a few possible combinations.
For those of you using a Y connector for two subs and neither sub has variable phase or an app, just follow the same steps as above if they are both on the front wall. If one is in front and one in the rear and the rear has a 0-180 phase switch, try it in both spots to see which gives you the most output
If you have subs with an app or variable phase that are connected with a Y connector, do one sub first (preferably the one furthest away from you) using the distance control on your home theater receiver, then add the second sub and change its phase until you get the highest level reading.
If you have two subs with no adjustments, but your receiver or processor has independent distances, follow the same steps just using the distance instead of phase for each one.
Room With Four Subwoofers
For those of you with four subwoofers, you likely have a home theater receiver or processor that has Dirac or Anthem Room Correction and it will do all of the phase adjustments for you.
At this point, it is a good idea to make a note of the distances you came to when you were doing phase as some receivers will get them wrong in the next step.
Final Receiver/Processor Calibration
Now that the subwoofers are all set up properly, if your home theater receiver or processor does not have any kind of room correction, simply go back through the test tones and balance all of your speakers out to 75db (with the combined level of all your subs at 75db).
If your receiver or processor does have room correction, follow its steps now. Unless your receiver/processor has phase alignment like Dirac or Anthem Room Correction, you will need to go back in after it is done and change the distance(s) for the subwoofer to the one(s) you noted after the phase calibration. Our experience tells us the other systems get the phase part wrong.
We also suggest you look at our tips on calibrating your center channel speaker and running through them after these steps are finished.
That concludes our tips on subwoofer setup. We hope this article was helpful and brought your home theater up a notch or two! If you have any questions or comments, feel free to reach out to us via chat, email, phone, or drop by one of our locations in Raleigh or Charlotte, NC.
FREE Interactive 3D Home Theater Design Tool
Enter your room dimensions, audio, and video preferences while it designs your theater in real-time. Receive optimal screen size, seating locations, speaker locations, and receive precise measurements for your room layout. Work with our system designers via chat, email, phone, or in-store for expert advice, product selections, and more.
Home Theater Buying Guide
If you are in the market for a new home theater system or improving part (or all) of the one you already own, you’ve probably figured out that the options can be more confusing than advanced algebra! Explore our guide to understand the available options and how they might work or not work in your particular situation. If you need help customizing a solution for your space, reach out - we're happy to help!
Today’s home theater receivers come with so many features, they can make your head spin. Just take a look at the specs on any brand’s website and you’ll probably see more than 50 features listed in the long list of advantages the brand is pitching you. Sure you want all of the latest and greatest, but in the end, room EQ optimization i...
Whether you’re researching for a future home theater installation or exploring ways to enhance your current home theater, we’ve created a series of videos to walk you through upgrades to make optimizing your setup easier — including everything you need to know, from tweaking your picture to improving the acoustics in your room. In this par...
If you are a home theater enthusiast, you are probably aware of how important a role the center channel speaker plays in a great home theater experience. Here, we will give some basic set up tips and hopefully even a couple of suggestions for experts that will help you get the most out of your center channel speaker....
Check out our free tips on how to improve the picture performance of your home theater’s TV or front projector. We go over some simple steps that will allow you to fine-tune your picture like a pro. Whether you have a new home theater or yours has some age on it, these tips are sure to make you smile when you see the improvements....
Imagine you are really getting into a great action movie, the spaceship lands, and all of a sudden, you hear this terrible buzzing or rattling sound coming from somewhere in your room. The effect of the movie has just been totally ruined. This tip breaks down how to find and eliminate noises your room might be making due to vents, furniture, li...
Follow along in our guide where we help explain how and give you the right tools to perfectly set lip sync in your home theater....
This tip is designed to help you nail down the right contrast and brightness settings on your television or projector. If you have not yet watched our Top 5 Tips for improving your Home Theater video, we would suggest you watch that first as it covers all of the major items you want to adjust in order, including brightness and contrast....
This tip is designed to help you perfectly focus your projector and is part of our Top 5 Tips For Improving Your Home Theater Video series. You can follow these steps using your projector’s pattern or we show you in this video. Make sure your projector has warmed up for at least 20 minutes before running this test....
If you follow these tips, you can substantially improve your home theater or media room. This tip breaks down how to get the perfect sharpness settings on your television or front projector....
As more original Dolby Atmos movies continue to come to streaming platforms, you will not want to choose upgrades for your home theater system until you watch our next video. Since you already own most of the key parts, you won’t even have to change that many components! We will cover essential tips & tricks to get great-sounding uncompre...
Have you ever wondered why you have black bars at the top and bottom of movies? In this video, we explain everything you need to know about widescreen. If you have a home theater or are thinking about building one, this video will demystify aspect ratios and explain how to design and set up your system to get the best experience possible for new...
One of the best ways to house your gear is in a commercial-like equipment rack. These types of racks have been used for decades in data centers, studios, concert halls, and high performance home theaters. We like them because they are very easy to service and make changing things out as you upgrade super simple....
We have some great tips for optimizing one or more subwoofers in a home theater or music system. You’ll learn how the room interacts with subwoofers, the best places to put a subwoofer in your room, and how to fine tune your subwoofer to deliver bass that has both great impact and fine detail....
Custom painting your speaker grilles allows you to virtually hide your speakers in plain sight – they’ll blend in with your walls, ceiling, or cabinet for a seamless visual appeal. If you’re reasonably handy, this do-it-yourself guide will walk you through how to custom paint your in-wall or in-ceiling speakers....
A Home Theater DIY guide on how to install in-wall and in-ceiling speakers for your home theater or media room. This video walks you through a live installation of Bowers & Wilkins in-wall & in-ceiling speakers for a home theater....
A guide on how to choose the ideal in-wall and in-ceiling speakers for your home theater or media room. This article will give you some insight into different types of built-in speakers and the best use case for each one. While some of these are great for music listening, we are going to focus on how to pick the best in-wall & in-ceiling sp...
A guide on the most common home theater mistakes people makes when building out their dream home theater. Learn about components people may not think of, that can have a tremendous impact on how immersive the home theater experience will be....
Today, choosing between a projector and a TV mostly comes down to the environment and how you plan to use the room. Let’s discuss two of the most common environments for TV and movie watching today, family rooms (or media rooms) and dedicated home theater rooms and which technology we recommend for different applications....
One of our top questions we get all the time is “how should I allocate my home theater budget to the many audio and video components that make up a great home theater system?”. There is nothing like achieving the movie theater experience in your own home. You, your friends, and your family will enjoy it for decades and our thousands of happy...
Learn all about the different possible speaker layouts for your home theater. We explain the best speaker configurations and how to integrate them into your room with options for almost any situation. We’ll help you understand the Dolby Labs speaker terminology and what is best for your home theater....
Learn how to choose the best size for your TV or front projection home theater system. We’ve culminated in the advice of the movie industry and our years of experience with real-world home theaters to take the guesswork out of helping you choose the perfect screen size. You’ll just need a tape measure and a calculator....