How to improve the sound quality in your car?

• Car Audio Systems
• Is car audio system replacement necessary? Design of car audio systems and the influence of their main components on the sound quality.
  • Main amplifier
  • Car stereo (radio and equalizer settings
  • Speakers
  • Arrangement of car speakers
  • Subwoofer
• Car audio system and sound improvement solutions.
  • Mats and door soundproofing
  • Spacers
  • Cables, mainly speaker cables
  • Cable ends and XLR connectors
• Catalogue of Car Audio products at TME

Many music lovers spend a lot of time in their cars. Therefore, it should come as no surprise that they put so much effort into improving the sound quality produced by their on-board audio system. There are two ways of doing that: expanding and upgrading the factory-installed audio system or building one yourself from the scratch with the use of highest quality components. In both cases, it is worth using the solutions offered by TME grouped under one clearly described product category: Car Audio.

Car Audio Systems

Back in the 1980s and 1990s, a car audio system was simply supposed to generate sound, with little focus on its quality. Usually, the most important feature was what types of data carriers it would support – cassette tapes, CDs, then even DVDs and files saved in various formats (Wave, MP3). Selectivity and clarity of sound were less important, though there were some noteworthy exceptions. However, we cannot overlook the fact that specific parts of these audio systems were of unknown origin, as car producers would commission building them to those with the best prices or those who had their business near the assembly facility. This changed with time, and just like the high-end Hi-Fi systems made by renowned manufacturers (premium products) have become popular in our homes, also our cars now often have audio systems of high or even excellent quality, from brands such as SONY (i.e.: Ford), Harman Kardon (i.e.: BMW) or Bang & Olufsen (Audi). At present, when they decide about car configuration, music lovers – no matter if we are talking about middle class or luxury cars – can choose, for an additional fee, an optional sound package available for their model, which provides average, high or very high sound quality. Still, the most fervent enthusiast of the purest sound quality may find even the acclaimed sound systems made by premium brands insufficient. In such cases, they head for specialized Car Audio shops or (if they have enough knowledge and money) make the improvements themselves. Out of these two factors that are needed for the latter option, knowledge seems to be much more important. The reason for that is the complexity of new car audio systems and the variety of subassemblies, accessories, and software available on the market.

Is car audio system replacement necessary? Design of car audio systems and the influence of their main components on the sound quality.

A car audio system made of components such as a radio, or more advanced multimedia system, main amplifier, which may or may not support a low-range subwoofer, high-, mid- and low-range speakers (woofers), a subwoofer, which is a separate transducer responsible for the lowest bass sounds (often having a separate amplifier), cables and various accessories and additional equipment (i.e.: antennas, sound deadening materials, spacers. etc.). Every part plays a crucial role in the audio system and can impact the sound quality of music. While the influence of some elements is very prominent and hearable, the role of other components is inconspicuous or sometimes even unnoticeable. However, each of them is worth having its own subsection.

Main amplifier

This element is necessary for the work of the drivers – it can help you achieve the high quality of sound and improve your control over it (drive it). It also ensures the higher volume level of the whole car audio system, as it is able to support bigger speakers – ones with a larger diameter and more power. This means that its influence on the sound quality is quite significant and that is why it is important to think thoroughly which amplifier to choose. For audiophiles, the most important feature is the minimization of the distortion level and the fact that the user gets a strong influence on the final timbre and dynamic range of the sound – however, this requires a high-quality amplifier with a build-in sound processor (Digital Sound Processor). For an average person who likes to listen to their favourite tracks in the car, the amplifier for the car audio system solely means hard basses and raising mid-range sounds. When choosing the amplifier, the key issue is not only its quality, but also the number of channels it supports, as this is reflected in the number of receivers that can be connected. For years, 4-channel amplifiers have been the most popular choice. They allow for 2 sets of speakers to be connected, a radio and a small- or medium-\sized subwoofer, though recently it is more common for the last element to be supported by its own, individual power supply system. Another important attribute of the main amplifier is its voltage, which cannot be chosen randomly. Its voltage has to match the voltage of speakers in the set, based on a rule that “power supply voltage = 1/2 to 2/3 of the voltage of the connected speakers” which results from the need to protect the speakers against damage resulting from too powerful PSU. That is why, if you decide to replace the speakers and the amplifier, you should first calculate these two values and match the amplifier (its voltage) to the target voltage of the speakers that you want to achieve.

Car stereo (radio) and equalizer settings

The car stereo (radio) panel is an element of factory-installed car equipment that is a part of its dashboard and affects the look of the whole interior. For that reason, the decision to replace it often requires some form of alteration of the dashboard, however just as often the whole process boils down to the purchase of a higher quality model of the same size, which guarantees easy installation in the factory-made frame. The function of a car stereo is pretty self-explanatory: to play the sounds from various data carriers and via wireless communication modules (CD / CD-R / DVD / USB stick / Bluetooth / Wi-Fi / radio waves received by an external antenna). This means that a car stereo has a direct influence on the sound quality in a car, comparable to that of the speakers. Whenever we start improving the sound quality in a car by upgrading the speakers first, the effect might not be what we expected, because even the best speaker cannot produce high-quality sound if the signal is weak. That is why the experts from the Car Audio field recommend that we should start from “the source”, i.e. simply replace the stereo receiver with a high-quality unit featuring the best possible drive, analogue-to-digital converter and – what is important for those who enjoy listening to CDs as they drive – a laser. Of course, the chosen equipment should be compatible with the system installed in the car, meaning that it should communicate with, for example, steering wheel controls, as well as offer an individual way to control the sound going through the subwoofer. Such a replacement – even with the factory installed speakers remaining in the car – quite often offers significant sound quality improvement. However, if we also replace the factory-fitted speakers with top-shelf ones, the effect becomes even clearer and can often fully satisfy the expectations of a sophisticated and demanding user of the car audio system.

Speakers

Speakers, alongside the car stereo, influence the sound quality generated by the Car Audio system. Based on their frequency range, they are often divided into low-, mid-, and high-range transducers, though often car producers use full-range speakers that cover all tones at once, which lowers the quality and selectivity of the sounds but is significantly cheaper. The diameter of a typical subwoofer membrane is at least 25 cm, the one of a mid-range speaker is usually 13 or 16.5 cm, whereas the high-frequency speakers, i.e. the so-called “tweeters”, are characterized by small membranes – their usual diameter is around 5 cm. Factory-fitted car speakers can also be categorized as component – physically separated – and coaxial, i.e. two- or even three-way speakers. In their case, over the big, low tone speaker, another one or two are placed – a mid-range speaker or a combination of a mid-range one and a tweeter. Regardless of the setup functioning in the car, these sets are often not powerful (efficient) enough and generate mediocre or low-quality sound. Sometimes there are simply too few of them, or they weren’t matched properly, and their layout is incorrect. All these errors result in similar problems: the audio system uses mostly mid-tones, but cannot generate selective high tones and low basses. In such a case, there are two solutions – you can either leave the speakers and fix the aforementioned errors, thus creating appropriate setting for them where they can fully use their potential, or look for new transducers if the factory fitted ones cannot be improved in any way.

Arrangement of car speakers

When choosing new speakers, you need to think about the appropriate diameter – nowadays, standard models are usually 100mm, 130mm or 165mm. You also have to, based on the model, brand, and the location inside the car, choose spacers with an appropriate inner diameter. This means higher efficiency and power demand at the same time, but the aforementioned amplifier solves that issue (usually the power coming solely from the stereo (radio) unit is not enough). Also, the required mounting depth is quite important (sometimes their magnets are too big and do not fit into the spaces where the previous, factory-made speakers were installed), as well as the location. Experts strongly advise against installing the speakers in the rear deck or anywhere behind the front seats, as it negatively influences the sound perception. After all, when going to a concert or listening to music on your Hi-Fi system at home, most of the time you turn in such a way as to face the source of the sound. Besides, our hearing and the way our ears are built make this the best way of listening. The optimal place for tweeters is somewhere around the dashboard, for mid-range transducers – well soundproofed doors are the perfect spot, while powerful bass speakers can be placed – mostly because of their size – at the back of the car. When installing new speakers on a steel surface, you should use spacers made of MDF (more expensive, but much more effective than their plastic counterparts) – that way the vibrations will not transfer to steel. The most crucial parameter that has to be taken into account when choosing new speakers is – next to the high quality guaranteed by a renowned producer – the efficiency of the transducer, indicated by dB/1 per W/1. This parameter describes the volume (sound pressure) generated by the speaker 1 meter away from it at 1W. Because the sound pressure is measured using the logarithmic scale, each increase of the parameter by 1dB equals to a more or less 35% volume increase of the transducer (when powered with the same current). Also, the power rating of a speaker is of great significance, as it describes the maximum volume of the transducer, but most importantly the maximum amount of electrical energy that the speaker can take. This means that even when powered with less energy, the speaker will still work effectively.

Subwoofer

This is basically the last of the key elements of the Car Audio system. Due to its size, shape (a box or a tube) and the diameter of the speaker, it is usually installed in the back part of the car where it emits the lowest tones – simply, basses. It can be powered by the main multichannel amplifier, but in modern systems – especially those upgraded, with high efficiency and power – this speaker is mostly powered by its own, individual amplifier. Do not forget that the amplifier power cannot be higher than the power of the subwoofer (otherwise it can be damaged), and that this element is an additional load for the car battery. Going back to amplifiers designed individually for mid-sized and large subwoofers, we have to point out the strong position of a single-channel device, called Monoblock, that reaches high stability at low impedance. Monoblocks achieve the highest available power efficiency while also producing “juicy” bass. The typology of subwoofers boils down to three most important categories: small, low-power speakers (Ø 20-25 cm and 100-200W RMS), medium speakers (Ø 30-35 cm and 300-500W RMS) and large speakers (Ø 38-40 cm and 500 or more W RMS). In terms of design, the box with one speaker seems to be a popular choice, however, there are also more and more dual speakers (both small and medium models) available on the market. Even the choice of the box might be something you want to think over, as the shops that specialise in Car Audio installations offer a variety of options, from bass-reflex, to closed boxes and band-pass.

Car audio system and sound improvement solutions.

Mats and door sound deadening

Sound deadening of car doors is often the first step in trying to improve the intensity of low and medium tones while eliminating the reverb, resonance or simply achieving a high sound pressure. Sometimes, thanks to this, the replacement of the speakers is no longer necessary. It can be done with the use of special self-adhesive sound deadening mats installed inside the car door. Mats are made from few different materials, however the mats manufactured with the use of butyl rubber covered with aluminium foil (to stiffen it) are the most popular ones because they are not too expensive and, most importantly, they maintain their properties in a wide temperature range (they work well both during winter chills and summer heats).

Spacers

Even though they have already been mentioned before, it is worth reminding that: these elements, usually made from MDF, are used for installing the speakers on steel surfaces as the separating and vibration absorbing element. Thanks to them the transfer of vibrations on steel is almost completely eliminated.

Cables, mainly speaker cables

In most cases of factory-fitted Car Audio systems, the most useful cables will be the ones with a cross-section of 1.5mm2 and made from oxidized copper. In such situations, the industry experts advise using the OFC cables with better conductivity, while the most demanding audiophiles buy from the start cables with a bigger cross-section (2.5 – 4.0mm), with the addition of or fully made of silver – which, of course, costs much more.

Usually, such changes result in much clearer, selective, and denoised sound, something that is instantly noticed by a trained ear, as long as the car is properly sound-deadened and no strong noise made by tires, wheel arches, A-pillar or side mirrors is heard. Equally important as speaker cables is the signal cable that connects the car stereo and the amplifier. In its case, multi-shielding is crucial, as is protects the sound from noises and other interferences coming from the car wiring system or other elements of the Car Audio system. The last cable that is crucial is the amplifier power cable which connects it to the car battery. Apart from proper protection against the influence of mechanical factors and heat (temperature under the hood can be quite high), its cross-section should be big enough to correspond with the current that it supplies (power consumption by the amplifier) and the cable length. If the power consumption of the amplifier is around 50A, you need a cable with a cross-section that is about half of this value – 20-25 mm2.

Cable ends and XLR connectors

This subsection deals with connectors which are probably the weakest link in the cabling construction, and which highly influence its lifespan. Using cables with high conductivity (see the previous subsection) and gold- or silver-platted XLR connectors with a screw-on tip to assure tight connection and higher deformation strength can improve the functioning of the Car Audio system.

Catalogue of Car Audio products at TME

The TME offer is very vast in this field and comprises various categories of different products – from simple ones, like car stereo frames, to more complicated ones like, for example, connectors for stereo receivers, or speakers, sold individually or as a part of a set. The search engine groups the products into categories, which makes it easy and simple to navigate the Car Audio offer. The following list presents the most important product sections that influence, directly or indirectly, the sound quality of car audio systems.

• Car antennas, including GPS, GSM, CB, TV and radio antennas, as well as connectors and adapters for them (from such manufacturers as: 4CARMEDIA, BLUEBIRD, JC ANTENNA, PER.PIC., FARUN, SIRIO, SUNKER, GOOBAY, DYNAFLEX, PHONOCAR, CALEARO and UNICON),
• Interfaces and AUX adapters(from such manufacturers as: UNI-TEC, 4CARMEDIA, BLUEBIRD and PER.PIC.),
• Car stereo framesproduced by: PER.PIC., METRA, ACV and 4CARMEDIA,
• Speaker adapters, active system adapters, car navigation adaptersand even steering wheel audio control adapters (made by: 4CARMEDIA and PER.PIC.),
• Connectors for panel car stereo, factory fitted stereo, ISO plugs and socketsand car antennas adapters (producers: 4CARMEDIA, PER.PIC. and UNICON),
• Car speakerssold individually or in sets, as well as speaker enclosures and MDF or plastic mounting accessories (made by: 4CARMEDIA, ACV, PER.PIC., BASSER and SILENT COAT),

Apart from these product categories, TME also offers:

• car power accessories,
• frames and half frames for car radio and CB units,
• radio-panel tapes,
• radio removal keys,
• CD changer cables,
• cables for HF Parrot and THB sets,
• heat shrink sleeves, electrical tapes, and many more.

Text prepared by Transfer Multisort Elektronik Sp. z o.o.

The original source of text: tme.eu