How to setup a subwoofer in your recording studio

On the topic of subwoofers, a question we often get asked is "what do all those switches and dials on the back of a sub actually do?".  It's a worthwhile question to investigate because these little settings can dramatically affect how your sub will perform when paired with a set of studio monitors. So, in this article we'll strip it down and define each individual switch and dial, with the hope that this provides you some fundamental knowledge with which to set up your newly acquired sub.

I will be confining this article to a stereo 2.1 system that you will most likely see in a recording or post-production studio. Also, when I say Satellites, I'm referring to your existing studio monitors that you are pairing with a sub (not the big metal objects flying around in space).

Subwoofer Placement

The placement of your subwoofer will depend on your room size, seating position and room acoustics. It's all about achieving a full, even integration of the subwoofer output in relation to the satellites. A sub will dramatically extend the low-end frequency of any system, and go lower than most studio monitors will on their own.  When dealing with low-frequencies, your room comes into play because in any room you will get a boost in low-end frequencies of about 6db when 2 walls meet. This increases when a third wall comes into play; like in a corner for example. Having a small room can dramatically increase low-end volume, especially if your seating position is close to a wall. In the diagram below you can see that the closer to a wall your sub is, the more bass output you will have, but you will also experience a slight 'blurring' of the bass response. Alternatively, if your sub is close to your listening position, you will have a more focused, integrated bass response, and the overall bass output will be lower. In any room I suggest starting with your sub in the position of the second figure below, which is middle and slightly behind your satellites.  From this point, move the sub either closer or further away depending on how it sounds. 

Subwoofer Size

Ideally, you want to match a set of studio monitors with a sub that has a bigger subwoofer speaker diameter than the low-frequency driver in your satellite speakers. Eg if you have a pair of studio monitors with a 6" driver, I would suggest getting a sub with at least an 8" speaker diameter, but I typically recommend a 10" to our customers. The reason for suggesting a 10" is that I personally don't like a sub to be struggling under load. As low-end frequency has more energy than the rest of the frequency spectrum, a sub will always be working pretty hard. So, better to have more power and size than have it flapping around and struggling with volume.

Connections

The best way to run a 2.1 system is to pass the audio through the sub on route to the satellite speakers. This essentially means you run your signal from your soundcard or monitor controller outputs into the L and R input of the Sub, then run the L and R output from the sub to your studio monitors. I suggest running your cables fully balanced: either on TRS cables or XLR if these connections are possible. In this configuration, changing the volume that you feed the sub (whether it's from your soundcard volume dial, or from a dedicated monitor controller) will change the volume of both sub and satellite speakers in unison.

Once everything is connected up, it's time to start playing with all the dials and switches! 

1. Phase 

This button is used for speaker placement, and will alter the phase relationship between the sub and the satellites. You will typically have a choice of zero or 180 degrees out of phase, however I have seen more options depending on brand. If you want to run the sub further away from your satellites (i.e in the corner of the room) I recommend hitting the 180 degree out of phase button to see if the sound becomes tighter. If you want to run the sub pretty close to your listening position, try zero. Leave the button in the position where both sub and satellite sound tight and 'as one'. 

2. Satellite Filter

The "satellite filter" is a High Pass filter that when engaged will limit the frequency range that is sent to your satellite speakers. Depending on the sub this can either be a single selection, multiple selections or completely variable. You can also run the satellites in full range, however I suggest setting the filter to about 80 Hz. This means the satellites will only receive frequencies above the frequency set by the High Pass filter - in this case, 80 Hz. Because the satellites aren't producing a full-range signal they aren't working as hard, and when paired with a sub that's pumping out frequencies of 80 Hz and below, the whole system can be a lot louder.

3. Sub Filter

The Sub filter is a Low Pass Filter that sets the upper-frequency limit of the subwoofer. It is typically fully variable. I suggest setting it to match the Satellite filter so that you eliminate any overlapping frequencies. This means if you have set your satellite's High Pass filter to 80 Hz, then set the sub filter to stop passing any frequency above 80 Hz.

4. Sub Level

This step is easy but is the most crucial. Sub Level is a dial that sets the output level or volume of the sub in relation to the Satellite. Change this dial to balance how loud the sub is compared to your satellites. I suggest setting it low, then get a friend to slowly turn it up while you sit in your natural listening position. Tell them to stop turning when you start to feel the sub kick-in. You don't want to overpower the system by having too much low-end volume as your mixes will suffer. The best way to know if your sub output is set accurately is to note when the music sounds even, full range and complete.  You really shouldn't notice that you have a seperate sub at all - it should blend seamlessly with the music. So, if you're thinking "wow listen to that killer bass" chances are it's too loud!

That's pretty much it. Once you've got it "dialed in", put on your favourite track, turn up the volume and have a good listen. The sound should be big and impressive without sounding too bass-heavy.  

Sounds Easy sells a range of Subs from brands such as; Adam Audio, Genelec, Focal, Mackie, Presonus and JBL. You can see all of our subs here!

Thanks for reading! If you're interested in getting a sub to add to your existing monitors, feel free to use the coupon code below at the checkout to get even more discount. 

*Coupon Code will expire on 1st September 2016. 

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