Car Audio System Design: What to Get Right First
In a car you never hear a speaker on its own. You hear it together with the cabin, the mounting and the tuning, so the same driver can sound superb in one car and ordinary in another. Peter Steinbacher of Pssound, a high-end car audio installer, builds everything around one idea: get the location, application, installation and tuning right first, and treat the price of the equipment as secondary.
The short version
Peter's priorities run location, application, installation, then tuning, with speaker and amplifier choice after that.
A rigid, vibration-free install of modest speakers beats expensive speakers that are just fitted in.
The car decides where each driver can work, and no speaker or DSP (a digital processor that tunes the sound) can rescue a bad location.
Tuning is last but often the biggest upgrade, and design knowledge shows what it can and cannot fix.
Hardware matters in a few places, above all the tweeter, and amplifiers come last.
A great system makes the speakers disappear and stays controlled when turned up.
Simple daily systems can sound excellent if they meet his minimum standard.
The order that matters most
Peter's recipe is short: location, application, installation, tuning. Location is where each driver sits in the car. Application is how it is used there, such as in a sealed box or on an infinite baffle (IB: the driver sits in a sealed wall and uses the boot or the outside air as its box). Installation is how rigidly it is mounted. Tuning is the final set-up of the sound.
He has repeated this order for years. Locations come first, then installing the speakers in the best way for their application, then tuning. Only then do you choose speakers and amplifiers, with the amplifier last (watch). A DSP cannot fix a poor installation, so installation comes before tuning.
Vibration is probably the biggest thing that can disappoint him. Whether bass sits in a floor-cut IB mount or an enclosure in the kicks (the side panels by your feet), it must be free of resonance, because every buzz is lost energy (watch).
He says to plan soundproofing first, before buying amps or speakers, because once the build starts you will not want to take things apart. Our guide to deadening and road noise covers how.
Leave the music source until last. People fret over hi-res files and costly players while their tweeters (the small high-note speakers) point away from them and fade out from 8–10 kHz (watch).
Why installation beats expensive equipment
This is a point Peter repeats often. He rejects the claim, made by some speaker makers, that an expensive speaker with a normal install beats a cheap one in a crazy install. In a Megane door, the window mechanism, motor and brackets still rattle behind a bit of deadening and a door card.
Pssound's S-Class demo car uses only £230 of midrange and tweeter. Peter credits the result to another 20 years of knowing how to get it (watch).
The Suzuki from his Cheap Sound Quality Car series has moderate equipment, an extreme install and at least 150 hours of work (watch). In the Brighton meet's group chat, people mostly name it the day's most memorable system, though they expect magic from systems with £10–20k of kit (watch).
Two several-time European champions in the Expert class could not see how his own Honda was so dynamic and controlled, and guessed at the priciest amps. It ran standard, unmodified Zapco amps and a Helix DSP Pro Mk1, then 5–6 years old (watch).
He sees no point paying over a thousand (pounds or dollars) for midbass drivers (speakers for the punchy lower notes) and mounting them where things resonate; one costing 200, built in properly, sounds far better.
If money is tight, start with cheaper speakers and do the installation properly, because speakers can be upgraded later (watch).
The car decides: location and aiming
Peter says what you hear is the car, the location and the application, with the driver itself probably the smallest factor. The same driver measures very differently in a Golf, a bigger saloon or estate, or a Transporter with a wall right behind you. When people suggested costly speakers for a high-end Mercedes E63, he said: "It's the car dictating what you can do, not your wallet." (watch)
So the first job is to find the best spot for each speaker. A car whose driver locations and applications are poor can never go beyond a certain level, however good the DSP or the tuner.
You cannot fight a bad location. EQ (turning particular frequencies up or down) can trim a peak, but a cancellation, a deep dip in the sound at one frequency, is game over (watch).
Location beats price. In the S-Class, swapping the Brax ML3 mid for the much rarer Micro Precision Z Studio gave almost no improvement, because the spot behind the door card carries its own character (watch).
Do not assume the factory door is best for midbass. Choose the driver after the location, going by its technical parameters for a kick, a door or a box, not by brand or price.
Aim every driver. Midrange and tweeters are more directional, and a badly aimed driver cannot be rescued with EQ. Peter says right aiming matters more than symmetrical looks.
Tuning, and why design knowledge comes first
Tuning is the last step, but Peter says it makes the biggest difference. In his view a simple day's tuning does more than replacing all the components, amps and cables (watch). If a DSP-based system disappoints you, get it tuned or checked before spending more.
Tuning rests on design. You must understand system design before you can tune, or you will not know why things happen or what a DSP can and cannot fix. That is why the first two days of his masterclass are theory.
He has become more confident over time. In 2018 he said you cannot predict a new location's behaviour unless you have done that car several times. By 2023 he said pretty much everything in car audio is predictable. His proof: after two days of theory, course participants measured their own cars, which Peter had not built or tuned, and a cancellation he had predicted at 72 Hz appeared at 72 Hz (watch). Sound, he says, is physics, not magic.
Tuning is a never-ending climb. Few people worldwide can do a correct tune, and it took Peter years to tune consistently. See our tuning guide.
Where the hardware does matter
Peter does not say equipment is irrelevant. His point is about where extra money pays off.
Tweeters are the exception. For midrange, midbass and subwoofers, location, application and tuning do most of the work. Installation can only change a tweeter's position and aiming, and no tuning can add detail the driver does not produce. A DSP can lift a top end that rolls off in the cabin, but not its resolution (watch). If you must choose where to put the most money in the front end, he says put it in the tweeter. See our tweeter guide.
Among hardware, speakers matter most (his 2022 view), and he says to upgrade amplifiers last. For a daily car, especially for someone new to fully active systems, he would now (2024) skip a stack of separate amplifiers without a very specific reason. Even DSP amplifiers, he says, sound so good that most people cannot tell the difference (watch).
A good DSP can make a $100 front three-way (tweeter, mid and midbass per side) and a $10,000 one read the same on a measurement. They still sound different, because transient response (how well a driver follows sudden changes in the music) and distortion matter a lot (watch).
Mixing brands is fine. The Skoda mixes four brands of speakers, and his Honda did the same for years without anyone caring when they listened.
Think about failure before buying made-to-order kit, which cannot be replaced quickly. The Insignia's top-end amps and DSP died twice, and the owner sold them.
What a great system should do
Peter's biggest goal is to lose the hardware. You listen to music, not speakers, and stop looking for where the sound comes from (watch). Once every speaker works in its range without cancellations or vibrations, and you know how to tune, they blend so well that all you hear is the music. He applies this to looks too: hardware you cannot see is hardware you do not focus on, and LED lights or a show boot do nothing for the sound.
Balance comes first. He calls equal amounts of top end, midrange, lower midrange and sub-bass the most important thing in any system, even if the staging (where instruments seem to sit) is not accurate.
Build in headroom, the spare capability to play loud without strain. Any car can tick the boxes at 80 dB, but his systems must reach at least 100–105 dB at the front end (watch). Do this even for owners who say they will not play loud, because they tend to turn it up. It must also sound good at low volume: "The first watt should count."
Enjoyment comes before scores. By 2023 he said he no longer cares about competition score sheets; the best moment is someone sitting in a car that gives them goosebumps or tears. He also notes that a car gives you far more listening time than a home room, since every drive is your own.
Layouts: the minimum standard and simple daily builds
Peter's minimum standard is a fully active system: a separate amplifier channel for each speaker, so each one can be given its own range and balanced on its own. He calls active with a DSP a must, and far easier than cutting the car up to a crazy level.
A basic two-way (door midbass plus a conventional tweeter) has a weak spot. The door midbass falls apart above about 300 Hz, leaving a hard stretch from 300 Hz to 2 kHz, where most of the information is (watch). So the absolute minimum Pssound builds is a three-way, or a two-way using widebands, fully active (watch). A wideband replaces the tweeter, covers from about 300–400 Hz up, and is easier to place high.
His preferred layout is a three-way front plus a front sub (a subwoofer up at the front of the car) and a rear sub.
A simple daily package is one amplifier with a built-in DSP running the front end, plus one sensitive sub in a sealed box (his workshop demo used a Zapco ADSP and a JL 13W3).
Cutting the car is a choice, not a rule. For really high-level sound he says cutting is unfortunately needed, but an everyday owner with good factory locations does not need it.
His scale: 7 out of 10 is the minimum Pssound builds. A simple daily system with a door midbass that still buzzes, plus custom pillars for mid and tweeter, can easily reach a seven.
Common mistakes to avoid
Buying expensive speakers before deciding where they will go and how they will be mounted.
Fitting speakers into a door or panel that still buzzes, and hoping tuning will hide it.
Chasing hi-res files, players and cables before the midbass, aiming and tuning are right.
Buying more gear when the system needs a proper tune.
Designing only for quiet listening, so the system strains the first time you turn it up.
Watch Peter explain it
This is an independent, plain-English summary of Peter Steinbacher's public YouTube videos, written by VA3 Car Studio. It is not affiliated with or endorsed by Pssound. The links jump to the moment in each video where he makes the point. Part of our series: Car audio lessons from Pssound, start here
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