Off-the-shelf monitor isolation products do indeed look the part but how can we know for sure that these types of tools work and if they do, how great are the benefits to our monitoring? Are they glorified gadgets or are they essential for our monitor performance?
In a recent episode of The Production Expert Podcast we explored some of the logic behind studio monitor isolation. We touched on a number of different types of off-the-shelf isolation that we can buy which all promise to improve the clarity of the sound of our monitors by means of decoupling cabinets from supporting surfaces, such as desks or large format console bridges.
Many of these isolation products can cost quite a lot of money whereas others seem to be much cheaper or come bundled free in monitor packages. Brands that specifically design and engineer monitor isolation products often support their marketing with scientific evidence designed to inform potential customers of the benefits these products provide and how they improve the sound of monitors.
When we go browsing for these types of studio tools, there are the strap lines from brands that state things like “optimise the sound of your monitors” or “decouple your monitors for an improved sound” along with evidence that appears legit enough to trust on face value… but is this enough to make an informed decision?
While there’s no reason to believe that the science behind monitor isolation is wrong we can’t ignore that reality that we, as end users, are not able to perform true blind-listening tests in the real world to determine for ourselves if these types of tools actually offer a noticeable enough improvement in our monitoring.
There are audio people out there, including top professionals, who swear blind that their chosen monitor isolation work wonders in their studio. While we would never argue with their opinions, we are somewhat curious how these engineers came to these positive conclusions in regards to their monitor isolation. As we discussed in the podcast, we feel it’s very difficult to be able to test and evaluate the performance of isolation products objectively in the real world for ourselves.
What Does Speaker Isolation Promise?
Monitor speaker isolation products simply provide a means of mounting monitors on surfaces while also acting as a means of decoupling and ultimately damping vibrations from monitor cabinets into the supporting surfaces. Damping reduced the transmission of vibrations from monitors to the surface. This is what is widely believed to improve the sound of studio monitors. Vibrations transmitted directly from the base of a set of monitors to a worktop of a desk is considered to colour the sound of monitors, which monitor isolation products promise to reduce the effect of.
Two Approaches To Minimising Vibration Transmission From Speaker To Supporting Surfaces
The basic principle is that the speaker should vibrate, but the thing on which the speaker is standing shouldn’t. Vibrations get passed readily between objects but the effect can be reduced in two ways. Coupling or Decoupling.
Coupling - If the speakers are mounted very firmly on something very heavy then transmission will be negligible, because the speaker cannot move what it is sat on. It sounds simple but in practice it is difficult to achieve. But there is an easier alternative.
Decoupling - The simplest way to stop a vibrating speaker from transmitting its vibrations into the next surface is to isolate it from that next surface, there are two approaches. I’ll call them spongy or spiky!
Spongy Isolation - By putting something soft and pliable between the speaker and the stand, it is possible to absorb the vibrations and pass on very little of them into the next surface. the choice of material is crucial here as it has to be suitably soft, but not too soft and it has to have the right damping characteristics. Products made from pliable materials and foam are all included in this category.
Spiky Isolation - This is the one which confuses people, us included, as the effect is counter-intuitive to most of us but unlike speaker stand spikes, which are designed to penetrate carpet and couple the stand base to the concrete floor beneath, as much for stability as for acoustic reasons. Spikes, or china cones rely on the effect trying to pass vibrations through a tiny surface area. Apparently this works as an alternative method for decoupling speakers in a similar way as the "spongy” methods.
Off-The-Shelf Products That Provide Speaker Isolation
Speaker Isolation Pads
These are typically the most affordable and common form of speaker isolation. The vast majority these isolation pads are made from high density foam and have been designed to be sandwiched between the base of monitor cabinets and the surface on which the monitors are intended to be decoupled and isolated from. The foam’s intention is to absorb vibrations from the monitor cabinets which in turn reduces the transmission of energy entering a surface, such as a desk that monitors are placed on. Many foam isolation pads have a slight angle on the top that enables users to either point their monitors up or down slightly or a foam insert that enables users to place their monitors flat.
Monitor Isolation Pucks
Monitor isolation pucks are quite popular. If you are considering a set you need to be sure that the product you are interested in was designed to be able to take the weight of your monitors. Users can either opt for using 3 or 4 pucks beneath each of their monitors as long as the pucks are positioned in such a way that means their monitors are stable and wobble free. Pucks generally have an inner core material between the top and bottom decoupling surfaces. It is with this core where the isolation/energy absorption takes place, acting like studio flooring floor isolation pads.
Monitor Isolation Feet - Cones/China/Spikes
Monitor isolation feet are available in a variety of styles including spikes, cones and chinas, all of which approach the purpose of isolation in a similar fashion. These types of isolation feet are small & ridged, typically with wide bases which shrink down to small pointed ends. The purpose of this shape is to reduce the surface area of the points of contact between the spikes and the speaker thus being a form of reducing the chances of vibrations passing from the monitor to the surface structure.
Desktop Monitor Speaker Stands
Similar to isolation pucks, desktop decoupling stands elevate and float studio monitors up and above a supporting surface. Many products of this type can also tilt monitors for better projection towards the ear as well adjust the height for better placement. This form of monitor isolation is available in many shapes and sizes.
The aim of using a heavyweight stand is to prevent the mass of the speaker from causing the speaker stand to vibrate by making the speakers stand so heavy that the vibrations of the speaker are too small in comparison the the stand to have any effect. Permanent brick or blockwork stands topped with concrete slabs aren’t unusual. Soffit mounting has a similar advantage though there are more advantages to soffit mounts than just the mass of the wall. Building a very heavy steel stand can work though its important to make sure that the stand doesn’t resonate or ring. A common approach is to fill hollow steel stands with dry sand or lead shot which add mass without transmitting vibrations.
How Can Users Test Studio Monitor Isolation?
The more we look into this area the more questions we end up with. How can a user decide if speaker isolation is worth investing in? Surely if we are spending significant amounts on speaker isolation we need to be sure that it is money well spent.
When it comes to testing speaker isolation, it is not possible to place two speakers in exactly the same place at the same time, one with isolation and one without.
If you are working in stereo, you have the challenge of not being able to co-locate speakers and the image width will be different, both of which will impact on the sound.
Most speaker isolation solutions will raise the speakers up so again the speakers are not likely to be in the same place.
If you add sometime between the speaker and the surface, you cannot be sure how much this might be affecting the sound, of the ‘control’ speaker.
Swapping out the speakers and adding an isolation product means you are dependent on a memory of what it sounds like and that is highly unreliable.
The best plan we have currently is to forget stereo and mount two speakers side by side in the middle of the room with one speaker isolated and the other not. Then switch the audio between them. At least this way the effects of the room etc will be minimised.
What About You?
Do you use speaker isolation? If so which type do you use? Please tell us in this poll below.
If you do them then please share in the comments how you decided which product to use.
Have you performed any tests on your chosen form of monitor isolation? If so, what was the test? Did your monitor isolation product come bundled with your monitors? Did you undertake any tests before buying them? If so how did you test the benefits of speaker isolation? Did you test them and decide not to bother? Please do share your observations and experiences in the comments below.