Audio Advent 2021 Day 3: Do I need a Subwoofer?

One of the questions that has been asked many many times across many retailers in many shops, is "Do I really need a subwoofer?" I'm going to try and answer that question for you.

Subwoofers do more than just create bass information, they help energise a room, allowing your other speakers, either in a stereo or a home cinema system, to have to do less work to fill the room with sound.

 

No matter how big your speakers are they will very rarely reach the bass frequencies that a subwoofer can. Even the biggest of floorstanders will generally only go down to about 30hz, whilst many subwoofers go down much lower than this, especially the bigger ones, like the REL T-9x .

In a home cinema system the situation is even more critical, as not only will the subwoofer be filling in bass duties for the rest of the system but also in any cinema soundtrack there will be dedicated Low Frequency Effects (LFE) information. This is the '.1'  in any of the following: Dolby 5.1, Dolby 7.1, Dolby Atmos 5.1.2,  Dolby Atmos 5.1.4 and all the DTS formats as well.

This channel contains information that's designed only for subwoofers to deal with, and if you don't have a subwoofer in your system then your amp/processor will attempt to divert this information back into the front channels, but as I said it's very unusual to have speakers that can handle this information.

Other things to note are, subwoofers are like children: they should be seen and not heard! If you can hear your subwoofer in a room, and be able to locate where the bass is coming from, then it's almost certainly too loud. Subwoofers should be underpinning the whole system, and when you can just hear them then turn them back down one notch of volume and that should be just about right. It's only when you take a subwoofer away from the system that you will realise quite how much it's doing.

Placement of subwoofers is quite important, Bass information is relatively omnidirectional but getting the subwoofer somewhere it will perform best is not too hard to achieve, We all know that if you put a speaker in a corner or up tight against a wall it will generally produce more bass information and this can be quite undesirable, but with a subwoofer this is exactly what you do want, as it means you can run the subwoofer less hard and use the room's natural amplification to get the best performance from your sub.

The places in your room where the bass is most powerful are called nodes. Generally a room has several nodes and if you actually want to know where they are, the best way to do it is to put the subwoofer close to your listening position and then work your way around your room until you find the places where the bass is loudest. These will be your nodes so if at all possible place your subwoofer in one of those locations.

A good rule of thumb is that subwoofers like external walls so if you have a corner of your room that has two external walls this is quite likely to be a node and a great place to put your subwoofer. Once it's there don't be afraid to experiment a bit with placement. Put on something you know really well and experiment with moving the subwoofer out from the wall a few cm at a time until you find where it's producing the deepest and tightest bass information. I often use a scene from the film U571 where the waves are crashing against the submarine.

REL subwoofers are special in a way that many other subwoofers are not in that they have both an LFE input and a high/speaker level input, meaning they can be used for both stereo and AV uses at the same time. One input is specifically designed to deal with LFE duties and the other designed to be run on the speaker outputs of the amplifier so that it can underpin the main speakers.

One final question you can ask yourself is whether one sub is enough!! Installing two or even three subs can seem like overkill but even in a medium-sized room a second sub can help pressurise the room better, meaning even less work for the main speakers to do; and when it comes to home cinema it can offer even more scale and depth for those big movie moments.

So, in conclusion, the answer to the question is very clearly "Yes! You do need a subwoofer!", for many of the reasons stated above, but which subwoofer you need is a question that we as a specialist can help you answer.

If you would like to hear a well set-up subwoofer, or two or even three, then please visit us at our Lincolnshire showroom or give us a call or an email and we will be very happy to arrange an appointment or have a chat about your subwoofer needs.

 

 

 

 

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