What Is The Subsonic Filter On A Amp For

Even among seasoned audiophiles, subsonic filters are a topic guaranteed to sow confusion. Some people ain amps with subsonic filter buttons that they never turn off for fear of breaking something. Others take adjusted theirs at multiple volumes and haven't noticed whatsoever divergence.

Notwithstanding it'southward non a topic amp owners can blow off. If you have an amplifier, preamplifier, subwoofer, or any other unit with a subsonic filter, and y'all desire to use it in a manner that won't destroy information technology prematurely, y'all need to know what your subsonic filter is and how to adjust it.

We're hither to help. Our Q&A covers all the big questions y'all might have about subsonic filters. If yous've got one we missed, let us know in the comments!

What is a subsonic filter?

A subsonic filter is a component on your subwoofer that reduces the intensity of notes which come up through at lower frequencies. It decreases the amplitude of those depression notes that y'all feel more than you lot hear. (To learn more about frequencies and how they work, bank check out our Beginner's Guide to Frequency Ranges.)

In other words, it's what we know every bit a high-laissez passer filter: a filter that lets through signals higher up a certain Hz threshold, and attenuates any signal beneath that threshold. Information technology'southward the opposite of a low-pass filter, which only attenuates signals above a certain line.

How does a subsonic filter work?

We've already named the main mechanic these subsonic filters utilize: attenuation. It'due south not super important to understand exactly how they're wired – it'southward a lot of electrical engineering without much consequence on what you need to know as the stop-user.

The only matter you do demand to know earlier we move on is that attenuation doesn't completely dampen sounds of a certain frequency. Instead, the number you lot gear up the filter to represents the frequency as which information technology starts to reduce the intensity of the audio.

If your subsonic filter is set to twoscore Hz, thirty Hz notes volition yet get through merely will be much quieter. Think of the filter every bit a slope, not an on-off switch.

Our Quick Guide to Bass Frequencies
Octave	Range	Center	Description	Instruments	Problem
1	twenty-40 Hz	32 Hz	Sub-bass, dial	Boot drum, bass, organ	Rumbling
2	40-80 Hz	64 Hz	Low bass, depth	Kick drum, bass, piano	Thud
3	80-160 Hz	125 Hz	Trunk, fat, booming	Drums, bass, keyboard	Unclear

Why would I want a subsonic filter?

If y'all're a true bass-head, you might be incensed at the thought that you'd want to cutting out subsonic frequencies. That's where all the os-shaking, window-rattling fun is!

We're correct at that place with y'all. We absolutely beloved the feeling of low notes thudding through our whole bodies. Merely in that location's something else we love just equally much: non having to replace our subwoofers once a month.

Subsonic notes sound awesome, merely they as well damage your hardware when they get out of command. As well many deep bass thuds tin can tax the limits of your woofer and cause information technology to wear out much faster than it otherwise would.

For you visual learners, the video beneath is a swell illustration of how low frequencies tin can misconstrue a subwoofer's cone alignment without a filter.

The trick is to find the right residue: loud enough that you can feel the bass, but attenuated enough that it'south not destroying your amp.

What nearly speakers without subsonic filters?

Some bass units on the market don't have subsonic filters congenital-in. While filtering is important, this isn't necessarily a dealbreaker — information technology all depends on what kind of music yous heed to.

Enough of genres never get anywhere almost the 50 Hz range. But if you're a fan of the ones that practise (and you know if you are), you lot need a subsonic filter to keep your subwoofers from rattling themselves to bits before their time. Check out the MTX Audio THUNDER1000.i Thunder Serial Car Amplifier for a bang-up amp with a subsonic filter.

How practise I apply a subsonic filter?

Nosotros've now covered the purpose of a subsonic filter and how it works. The next pace is knowing how to make your high-laissez passer filter work for you.

The best matter to do is listen. Play some of your favorite bass-heavy tracks and adjust the filter threshold downwardly until the low notes first to reflect. So adjust information technology back up until the bass notes tighten up again. That's a neat way to find that balance nosotros talked about above.

However, you might be the kind of audiophile who's more into hard numbers – or y'all may merely want a hint on where to start. If either of those are true, read on, and we'll get merely a little bit into the weeds.

Your approach to adjusting your subsonic filter depends most heavily on i thing: whether your subwoofer is fix in a sealed or ported enclosure.

If y'all aren't sure which ane y'all have, you can tell by just looking at the box. Is the hole for the speaker the simply hole? If yeah, you've got a sealed enclosure. If not, it's ported.

What's the best fashion to adjust a subsonic filter in a sealed enclosure?

Sealed enclosures work just like nosotros've described: low subsonic frequencies, particularly xx Hz and below, damage the structure, so nosotros want to attenuate them as much as we can. Since the Hz setting on the subsonic filter is the start of a slope, non a cutoff, we want to set it college than 20 Hz.

The sweet spot for getting some pounding bass without destroying your subwoofer is between 25 Hz and 35 Hz. Inside that ring, information technology'll vary depending on your chosen music and the residual of your setup.

What if I have a ported enclosure?

And then information technology gets a picayune more complicated. On ported speaker enclosures, you have to tune the port to its optimal frequency. Explaining that is beyond the scope of this Q&A, though if you're merely at present learning yous should melody your subs, this video is a groovy explainer.

The tuning frequency acts as a second high-pass barrier, but it does non replace the part of a subsonic filter. Besides many subsonic notes tin still damage your subwoofer.

A ported sub tin can safely play about half an octave below its tuned frequency before in that location's a gamble of damage. That means the safest setting for its subsonic filter is half an octave below any frequency the port is tuned to.

The hertz scale is logarithmic. Each octave upwards is twice as many Hz every bit the previous one, and dividing any frequency by 2 takes it one octave lower. Therefore, to get your subsonic filter setting, accept your subwoofer's tuned frequency and multiply it past 0.75. So, if it'southward tuned to 40 Hz, set the filter knob to 30 Hz.

Conclusion

With all the detail we've gone into, it's piece of cake to forget that near of these changes aren't audible to the human ear. If you don't like to crank your volume upwardly that far, you might never notice whatever divergence in subsonic sounds.

But if yous understand how to conform your subsonic filter, and practice doing it correct, you might reap some big rewards. Not just volition your low-frequency sound be less distorted, but your expensive subs will terminal a lot longer.

Thank you for reading, and as always, feel costless to audio off in the comments below. Savor your side by side ride with your newly counterbalanced bass rails!

Featured Image Credit: slightly_different, Pixabay

Contents

1 What is a subsonic filter?
2 How does a subsonic filter work?
- 2.1 Our Quick Guide to Bass Frequencies
iii Why would I desire a subsonic filter?
4 What about speakers without subsonic filters?
5 How practise I use a subsonic filter?
half-dozen What's the best manner to adjust a subsonic filter in a sealed enclosure?
seven What if I have a ported enclosure?
8 Conclusion