How to Set the Phase and Crossover Frequency on Your Subwoofer

Norvan Martin
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Properly managing your processors and receivers is critical if you want to get the best audio performance from your audio system. properly managing your audio system will require frequency control.

Most systems will recommend 80 Hz. However, not all systems are easy to tune to that frequency.

So, we will discuss specific tips to help you get it right when you need to set the phase and frequency on your speakers and subwoofers. Of course, these tips are general and therefore not specific to any brand or type of subwoofer.

What Is The Phase of a Subwoofer?

You may be asking ‘what is phasing?’ Well, let’s explain in simple terms. When you are producing sound from multiple sources, such as two or three speakers, there is a risk of being out of phase.

This means that each source could be contradicting the others. What do we mean by contradicting? Well, speakers produce sound by vibrating back and forth in a constant cycle.

What Is Speaker Phase

If speakers are in phase, then they are vibrating at the same rate back and forth and at the same time (the vibrating cones move in the same direction and at the same rate). When speakers are out of phase, it can lead to much distortion.

For example, when subwoofers are out of phase with each other, the bass quality coming from each speaker will effectively cancel out that of the other. This results in poor-quality sound.

To get your speakers in phase, you will need to do the following:

1. Set all of your speakers so that they are facing the same direction.

2. Ensure that speaker wires are aligned (wires are connected to the same terminals). In some cases, speaker wires cannot be switched. These speakers normally have a phase switch that you can use to switch around the polarity.

3. Now carefully listen to the quality of the sound from your speakers that should be in phase. If it still sounds muddy or distorted, then flip the phase either to 0 or 180– listen for quality- and that should be it!

4. If your sound system’s bass is important to you then you may also want to set your subwoofer LFE+MAIN settings as this also affects your subwoofer’s performance.

How To Set Subwoofer Phase

To eliminate distortion in your audio system, one of the most important considerations is phase.

However, the first step is to determine if your subwoofer is out of phase.

The phase of a subwoofer is a major determinant of how your overall audio system sounds.

setting speaker phase

So here’s how you phase your speakers:

1. Position Your Subwoofer

You should also check what orientation the subwoofer is meant to work in. Ensure your subwoofer is in its final location, as changing its position can affect the phase relationship with other speakers. Subwoofers are omnidirectional so it normally does not matter much.

2. Start with 0 Degrees Phase

Most subwoofers have a phase switch or knob, usually ranging from 0 to 180 degrees. Start with it set to 0 degrees.

3. Play Test Tones or Music

Use bass-heavy music or test tones to assess the bass response.

4. Adjust the Phase

While the music is playing, adjust the phase control. Listen carefully for the point where the bass sounds the fullest and most integrated with your main speakers.

5. Fine-Tuning

This process may require back-and-forth adjustments to find the optimal setting.

What is Speaker/Subwoofer Crossover?

Crossover is the frequency at which speakers begin to roll off, and the subwoofer starts outputting bass notes and LFEs.

Explained differently, crossover is where the unfiltered audio signal is divided according to a predefined upper or lower frequency threshold.

As explained yet another way, crossover refers to the point at which your receiver stops sending bass to each of your speakers and starts sending it to your subwoofer.

In other words, speaker crossover ensures each audio driver is provided with the signal range it was designed to best reproduce.

As an example, crossovers ensure that tweeters only receive the highest frequencies and that subwoofers receive low frequencies.

What is Speaker CrossoverBecause of this, crossover ensures that each audio device only receives the frequency ranges that it is designed to handle.

Not any of the lower ones this driver was not designed to reproduce. As you might imagine, crossover is rather important!

If your system has an EQ feature, it is best to leave the system alone and simply set the EQ. However, if you want to set crossover manually, here’s how you can go about it:

  • Check the speaker’s tolerance range/frequency range. If you don’t know the range, use a subwoofer matching tool. This tool will recommend the ideal SVS subwoofer for your speakers and tell you the best crossover frequency.
  • Now set the crossover point 10 Hz higher than the low end of your speaker’s tolerance range. In other words, set the crossover point roughly 10 Hz above the lowest frequency your speakers can cleanly handle. Keep in mind that the most common crossover frequency recommended (and the THX standard) is 80 Hz.
  • Now carefully listen to the speakers and subwoofer. You are listening for a smooth transition between the subwoofer and the speakers. The blending/transitioning should sound clean and seamless. When this happens, you won’t be able to localize the bass and everything will play in unison.
  • In some cases, you might notice issues such as a bass bump at the crossover frequency. If you notice this, try adjusting the volume control to match the output of your main speakers.

Speaker crossover is a component of every speaker, except full range speakers and speakers controlled by software.

In fact, crossover is a component of many other audio systems including amplifiers, receivers, and subwoofers. Most importantly, speakers with more than one driver in their enclosure require a crossover.

setting speaker crossover

If you are working with a car stereo, check out our guide on how to set high pass and low pass frequency filters on a car stereo receiver. You can also use this speaker crossover chart and calculator to calculate the crossover frequency of a certain speaker circuit. 

How To Set Subwoofer Crossover

1. Understand Your Speakers’ Frequency Range

You should be familiar with the lowest frequency your main speakers can handle effectively. This information is typically found in the speaker’s manual or the manufacturer’s website. The specifications section usually lists the frequency response of the speaker. 

You can also check the label of the speaker. Most speakers have a label or plaque on the back or bottom that lists their specifications, including the frequency response.

If you have trouble with any of this, you can always contact the manufacturer and ask.

2. Set the Crossover Point

The crossover frequency should be set slightly above the lowest frequency your main speakers can reproduce. For instance, if your speakers go down to 80 Hz, set the subwoofer crossover between 80-100 Hz.

3. Use a Receiver or Preamp Settings

If you are using a receiver or preamp with a built-in crossover, set the crossover frequency there.

4. Adjust by Ear

Play a variety of music and listen. The goal is a seamless blend where you can’t easily pinpoint the crossover from the subwoofer to the main speakers.

FAQs

Why Are Speaker Phase and Frequency Response Important?

Speaker phase and frequency response are very important for many reasons. The primary of these is really sound quality.

With speaker phase and frequency response set up correctly, your speaker and subs will be able to play all the low, middle, and high tones correctly.

This means you will experience loud, rich sound. For example, subwoofer box designs are done deliberately the way they are dor for proper phase and frequency response.

How Do I Know My Systems Frequency Range?

In most cases, your speaker’s manufacturer will provide specs that indicate where your speakers stop producing bass.

As an example, you may  see something like “Frequency Response: 60Hz-20kHz.” What does this mean?

The manufacturer is indicating that the speakers can play to 60Hz, but often the bass is much weaker at its lowest-rated point than it is in the rest of its performance range. Because of this, you will want to move the number up by 20Hz or so to be on the safe side.

The numbers below highlight general guidelines for speaker/subwoofer crossover frequencies

  • On-wall or tiny ‘satellite’ speakers: 150-200 Hz.
  • Small center, surround, bookshelf: 100-120 Hz.
  • Mid-size center, surround, bookshelf: 80-100 Hz.
  • Large center, surround, and bookshelf: 60-80 Hz.
  • Very large center, surround, bookshelf: 40-60 Hz.
  • Tower speakers with 4”-6” woofers: 60 Hz.
  • Car woofers (5.2″ and 6.5″ woofers): 80 Hz
  • Full Range Tower speakers with 8”-10” woofers: 40 Hz or Large/Full-Band.

What Frequency Should I Set A Subwoofer Crossover?

If you want to set frequency range, knowing the subwoofer frequency range is even better. Set the crossover point about 10 Hz more than the lowest frequency the speakers can reproduce.

Generally, 80 Hz is the most common and recommended crossover frequency. It is also the THX standard.

How Do You Adjust Crossover On A Subwoofer?

Should you want to adjust the crossover on your subwoofer, look at the back of your subwoofer. You need to set the low-pass crossover at least 10 Hz higher than your main speakers’ range.

This is the starting point when configuring your crossover. If your center speaker can produce 80 Hz to 120 Hz, you want your low-pass crossover to be anywhere close to 90 Hz.

This is actually the starting point when configuring your cross-over. If your center speaker can produce 80 Hz to 120 Hz, then you want your low-pass cross-over to be anywhere close to 90 Hz.

Conclusion

In summary, effectively managing speaker phase and crossover is crucial for superior audio performance. Setting your phase correctly ensures alignment and reduced distortion. On the other hand, setting crossover correctly ensures each speaker operates within its optimal frequency range. In general, this overall fine-tuning is essential for a balanced and high-quality sound experience.

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Norvan Martin is the founder of BoomSpeaker.com. He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics. My email: [email protected]  Connect on Pinterest and Linkedin