Under My Skin - Skinz Acoustic Treatment
We routinely mention sound deadening as a by-line to every article we write. High time we had a deeper look into this strange but very obvious requirement.
Let’s go back to the beginning. Why are good quality speaker cabinets so heavy? In order to get the most out of a pair of speakers, it is essential that they are mounted in a stable environment. By this I mean one that is not going to change too much at any given moment in time. With the luxury of static speakers, this is achieved by making the boxes as solid as possible. However, this fundamental of speaker cabinet design is not available to the in car listener where weight and size are often restricted and the priority to keep a vehicle’s interior looking as untouched as possible can be an added burden to even the most expert of installer.
Over the years, several materials have been made available to treat the environment that motor manufacturers give us. This has given rise to many brands with fancy packaging and “funny” names to navigate through. For the purposes of this explanation, we are going to focus on Skinz as it has as complete a range of solutions as any other and we are big fans. With products that deaden, diffuse and line, the area of acoustic treatment can be as much a minefield as purchasing electronics. The one overriding recommendation here though is that any treatment is better than none at all.
Skinz Expert and Skinz Pro are two forms of the same thing. They consist of several layers of bituminous material sandwiched between a foil backing on one side and an adhesive backing on the other. The principle is that adhering a sheet of one or the other to a flat surface of tin like a car door skin for instance, will help to stop it from vibrating. The vibrations can happen as a result of structural or air-born transmission of road noise, or by the movement of a speaker cone. Any of these causes is undesirable and applying these products will reduce the effects hugely. In some cases such as converted panel vans, it may be necessary to affix Skinz deadening to as many panels as possible just in order to be able to hear “the wife” offering cheery directional information whilst on a long journey or maybe to reduce the sound of rainfall on the roof of your camper whilst trying to sleep out in the wilds. Such examples however, simply suggest the amount of deadening required rather than offering a deep explanation.
As metal is relatively rigid, a large unsupported surface area will naturally have a resonant frequency. This is one that will make the panel vibrate in sympathy with other causes of that frequency. These are the most undesirable of all vibrations, as they will act to over amplify that frequency when reproduced from a source including music and add unwanted colouration to the sound. At other frequencies, a resonance can also cancel out harmonics or overtones that will have the same effect. It is essential therefore, to deaden at least the panel to which the speaker is going to be mounted against. So why have two types? This simply comes down to how susceptible to vibration the panel to be treated is. Skinz Pro is new to the market and is just 2mm thick. This makes it much easier to apply and is therefore perfect for secondary panel damping or use on panels that do not have a speaker mounted on them. Skinz Expert is 3mm thick and suited to door panels, floor panels and bulkheads liable to transmit the most road noise. Some vehicle manufacturers will employ their own systems to reduce noise however, as with speakers and amplifiers, the major design criteria tends to be price rather than efficacy.
As with all scientific solutions, there is no single perfect material for treating a car door. Even with Skinz Expert, there are other measures that can be taken to make the environment even more stable and help to project more sound into the vehicle. Although the bituminous layers previously described are very good, they do not totally eradicate the problem of vibrations. To this end, Skinz have what they call a panel liner available too. This is thicker but much lighter and looks very much like a neoprene membrane you might find used in a wet suit. The principle is that the cell structure of the neoprene absorbs and dissipates vibrations even further when used in conjunction with Skinz Expert or Pro. Skinz Panel Liner is available in either 10mm or 6mm thicknesses.
The final acoustic treatment solution from Skinz is called Wave Diffuser. Once again it is a foam based product but much thicker than panel liner and does a very different job. Rather than damping metal panels, Wave Diffuser is designed to sit directly behind a speaker. A speaker cone moves both forward and backwards when producing sound. As a speaker chassis is open at the rear, sound emanating from the rear can be reflected off the surface behind it and adversely affect cone movement and shape. Wave diffuser has a form much the same as the inside of an egg box. Its role is to “scatter” the energy coming from the rear of a speaker to prevent it reflecting back with enough energy to compromise performance. This ensures that even more sound is projected into the vehicle.
Often dismissed as an unnecessary dark art, sound treatment for your car really does work. Could you treat the doors in order to make factory speakers sound better? Undoubtedly yes, but while you have the door cards removed, it would be much better to replace them. Whatever the esoteric badge on the speaker position may say, you are unlikely to find that same name stamped on the rear of the speakers. Change them even for something modest to realise unbelievable improvement. Do you need sound treatment? No, but your speakers can perform up to 40% better with it.
In association with our partners The FOUR MASTER Network, we are able to provide you with a no obligation custom quote on a system for your car.
Not ready for that yet? Why not book a demonstration at your home, place of work or with your local FOUR MASTER?