Focal Car Audio Q&A

Listed below is a selection of questions by existing and potential users of Focal product.

If you have any questions specific to you please do not hesitate to contact one of our dealers or us. Even better if you have time call into a Focal dealer and experience for yourself the “Spirit of Sound”.

Is it wise to search for the cheapest possible price online? - Courtesy FHRX Studios

This discussion originated as a thread on Mobile Electronics Australia however over the years we’ve had so much correspondence about it that we’ve now transferred it here for preservation.

When it comes to car audio there’s an elephant in the room we seldom discuss; whether it’s wise to always seek out the lowest possible price online when purchasing equipment, or whether you should instead look to develop a working relationship with a technically competent store. The original discussion went for many pages, so we’ll just simplify it into four quick points.

Part one – What your local stores require from you.
Whilst this ought to be obvious, it only takes a minute of discussion with some people to realise it’s not. That is the concept of how stores work; not just car audio stores but all stores worldwide. We intrinsically make a living by selling products for slightly more than we buy them. Most people understand this basic commercial phenomenon yet we still get person after person asking for everything to be sold for next to nothing. Bear in mind the money you pay us, whether it be product mark up or for work undertaken; is actually how we pay our mortgages, rego, insurance, groceries, gas, water, electricity et al.. This is not to say we expect you to pay top dollar; not at all. For all shops will discount prices, offer package deals, hold group buys and so on. But you cannot expect a store sell you everything at cost price, nor should you expect them to undertake your $1000 install for $250. If you’re not clear why then go to work tomorrow and inform your boss you won’t be requiring any payment this week. Sure he’ll love you, but how long will you last in the real world?

Part two – What your local stores are offering you.
When you employ a store either by engaging with them technically or having them install a system in your car you’re actually buying a service, not just a product. Sure it’s easy to have the mindset to buy everything online as cheap as possible but this action actually makes life difficult for stores, especially when they’re offering a premium service. In the fair dinkum department we’re not silly; we understand that if you’re shopping for a single standalone item like a microwave then by all means visit three hundred websites and make twenty thousand phone calls. But when it comes to car audio products and installation you’re moving beyond simple product purchasing, especially when you start partaking in discussions about how to get the best out of said products. For you’re tapping into a stores knowledge and experience. There is an old saying in this industry that states “you can price match but you cannot knowledge, service or experience match”. With this in mind consider what services your store is offering you. I cannot vouch for all stores but some of the services we offer include:

Constant tune tailoring. Every weekend we have people everywhere down here using the oscilloscope and real time analyser for tailoring their system tuning. We often help them too, listening and explaining everything as part of our service. This is often done free of charge.
We constantly give people off cuts of sound deadening and cable for free when they need it.
We help people find and solve system problems for free.
We chase noise (hiss, whine) issues in peoples installs for free.
We help people find and solve rattles for free.
We let people trial new equipment if they want to see how it goes in their car.
We write a lot for magazines meaning we get to audition many products we don’t hold accounts for. This means we can advise people of what products to use and what to avoid for any given budget.
We offer free postage on just about everything. This includes when we send your components away for repair.
We fit and remove products often for free after the initial install price is charged (if you upgrade your amplifier for example).
We often buy products back off people if they wish to move sideways with a product (changing amplifiers for example).
We often re-install dodgy system installations for a significantly reduced or free price because we’re of the opinion that you shouldn’t be charged twice for the one install.
We work all hours of the night to fit into people busy schedules. Spare a thought for our spouses, children, friends and families who often don’t see us until well into the night each day.
We answer email enquiries within minutes, not days.
We offer free yearly battery servicing (discharge, test and trickle charging).
We offer free bench testing of existing components.
We offer free system and enclosure design if you’re not sure how to design the best enclosure.
We run and fund car audio BBQs and competitions.
We pick people up, drop them off and not just to the local station either; last year I dropped a customer off at Jindabyne which is a thousand kilometre round trip.
We often spend hours installing processors into people’s cars in order to show them what they do rather than trying to explain it verbally. Again; all for free.
Now they’re just the labour related things. Then there is the material aspect of service. These are the products and miscellaneous items we often provide without charge:
We’ve given people replacement speakers free of charge in the past. The most recent example was when we gave Wayne a replacement Boston Z6 midrange when his amplifier died and damaged an existing one; that’s a $300 driver by the way.
We gave Doug a free Audison sub controller.
We gave Zenafore a free dash kit because I had it sitting here taking up space.
There are countless numbers of people on here that we’ve given earth upgrades too, just to show them how their amplifier works better once it can get serious current.
We offer people free drinks when they’re here.
We’ve given many people many small things like fuses and terminals.
We’ve given people alarm items such as glass break and tilt sensors for free.
We’ve done free amplifier repairs for people whose product damage wasn’t their fault.
Finally there are the various aspects of the install itself. When it comes to the physical install all stores charge a certain amount for hour for labour, however we regularly spend up to four times the actual man-hours to get your install just right, all without charging you a single dollar more.
So after reading through the aforementioned lists you’ll hopefully appreciate that it can get a little despairing when people bring us a boot full of equipment they’ve bought somewhere cheap online and then ask us to put it in cheaply and preferably immediately. All whilst expecting us to maintain a high standard.

Part three – What are the negative consequences for you if you’re not supporting the local industry?
When purchasing products cheaply from online stores you’re exposing yourself to various risks. The most obvious of course is that the product you ordered plain doesn’t turn up. However some of the less obvious ones are:

Some of the products sold are fakes. We constantly see people buying equipment online, only to seem surprised to find their brand new $1000 speakers they only paid $100 for aren’t the real McCoy.
You might get evaluation, test or malfunctioning stock. If you have a look around various websites such as ARC Audio and Zapco you’ll see numerous warnings against buying online for these exact reasons. We cannot tell you how many times people have brought stuff online only to find it’s either used or malfunctions when they power it up.
Lack of warranty. Many manufactures track their products via serial number and won’t provide any warranty if they’re not in the continent they were initially distributed too. To get around this many online stores simply remove the serial number. This will net you the same result; no support at all.
You have no avenue for returns much of the time. If you get a new set of speakers and they don’t fit into your car, many local stores will gladly take them back. This is very rare if you’ve bought them online.
Part four – What are the negative consequences for the industry itself if you’re not supporting it?
Taking your business elsewhere doesn’t just impact upon us car audio stores, but upon many facets of the industry. Some of these include:

Stores close down due to being forced to compete with prices under their cost price. Importers close down due to shops not asking for any stock. The only winners initially appear to be you. But who will you turn to for assistance once all the knowledgeable and experienced shops are no longer around?
Information websites and forums suffer because the funds they depend on, funds that come from shops and importers; cease to come in. This means less free information, advice and assistance for you. Reliable assistance we mean, not just old mate on FaceBook who’s thrown together a few systems in his time and is now apparently an expert.
The product itself suffers. As more and more people simply chuck equipment in their cars on the cheap, sadly many have very limited knowledge about how to get the best possible sound from it. This means that the entire quality level of the car audio industry goes down as a whole. There is a good reason why specialist shops are called ‘specialists’.
The brands suffer. Leading on from the previous point; many big name brands are barely considered anything more than entry level these days. Sadly this perception hasn’t developed because they’re bad quality per se. It’s because the people installing them cheaply have zero clue, ergo they reflect this by performing terribly.
Competitions suffer. Stores sponsor and run many of the sound offs we all compete at. Without stores it’s quite likely there will be limited (if any) sound offs.
Publications suffer. When stores and sound offs start disappearing, advertising is no longer required and feature cars are in less abundance for publications. Therefore; what direction are the rags like INCAR Magazine going to go?
In conclusion.
Now we’re not fools; as aforesaid we appreciate completely that you can save a lot of money online, and whilst we don’t like to admit it we tend to agree that if you can legitimately save thousands off your products then you probably ought. But don’t buy everything online to save yourself fifty dollars and then expect stores to bend over backwards for you. We’re all more than happy to help you regardless of where your equipment came from; i.e. we’re not that stringent. But keep the following three points in mind. Firstly remember you might just be shooting yourself in the foot by purchasing everything cheaply online thereby killing off the local stores. Secondly; keep in mind that just like you we need to make a living by charging a fair price for your install. Thirdly; why not give your local store a chance to at least price match before you send all your cash online?


I am purchasing an ES165KX3 and EC165K and already have a peer I sting sub. I don’t want to run multiple amps. Does focal have any 1 amp solutions that can handle the power requirements of the speakers, in particular the ES165KX3?

The ES165KX3 don’t need massive power, like most of our speakers they are very efficient.
I don’t know what a peer 1 sting subwoofer is, I can’t find it on Google. Without understanding the specs of the sub, it’s hard to advise you.

We have a possible candidate, the FPX5.1200

If this is a massive subwoofer, I would like to suggest keeping it on its’ own amplifier. Subwoofers are ‘current-hungry’, especially big ones. If the music includes a lot of bass they tend to suck all the available power from the amplifier and the remaining four channels will be struggling to provide clean sound.

If you want really hifi performance you might consider a special sound-quality amplifier like FPX4.400SQ and a subwoofer amplifier FPX1.1000. The SQ amp will have adequate power for the front three-ways and the rear co-axials and you have the subwoofer isolated on its’ own amplifier. Just a thought . . .


I want to power two E30KX 12 inch subwoofers, should I use a single amp that is rated at 2400 watts into one ohm or two Focal FPX1.1000 amps rated at 700W RMS into two ohms? The cost of one single amp and two Focal amps is similar, around $1400.

I would prefer to see two separate amplifiers since you are running two heavy duty subwoofers. The weakest part of an amplifier is usually the power supply which is a collection of oscillator, transformer and capacitors which collectively raise the voltage from 14 volts to around 70 or 80 volts on the high voltage rail. I think two separate power supplies are preferable, two amplifiers, one dedicated to each subwoofer.

Many amplifiers can put out their rated output for a short burst and therefore can claim massive power output. However when presented with sustained load and asked to produce that output for ten, twenty or thirty seconds, it’s another story. If the voltage on the high voltage rail sags because the power supply can’t keep up, the bass loses some of it’s impact. Two amplifiers would be my choice, rather than one big amplifier working hard.


I have two E30KX subwoofers I am about to instal. What amplifier should I use?

To get those subwoofers to kick hard they should have one amplifier each. Subwoofers are ‘current-hungry’, more than any other speaker they require big surges of power. Sharing one amplifier between two big subwoofers in this category, no matter how big the amplifier, is not going to be as good as having one amp dedicated to each subwoofer.

I would recommend FPX1.1000’s.

The power cabling needs to be heavy duty, not just the positive cable through to the amps but the earth return. The weak spot is the engine-to-chassis earth which regrettably even a lot of professional installers don’t understand. You need a heavy earth cable joining the car chassis to the battery negative terminal. From the factory all cars have a heavy cable to the engine block to carry the current for the starter motor, and a small earth wire from the engine block to the chassis to carry the earth current for the lights, wipers etc. That small cable is not adequate for the current surges demanded by large amplifiers you are adding, which can be above 100 amps.

That’s a side-issue from your original question as to which amps to use, but if you don’t get the cabling right you are restraining the new amplifiers output.


I have a 2013 Ford Focus with the factory Ford/Sony head unit. I currently have a set of old aftermarket speakers playing in front but they are failing. They are rated at 70 watts, what do you think I should replace them with?
Don’t worry about matching the power ratings, Focal speakers are very efficient so don’t need a lot of power to work. But if you want to boost the power with a small amplifier we make a tiny amp that will hide behind the dash called Impulse ($359 retail), plus an ISO cable kit that lets it plug into the car wiring harness without cutting any wires IY Impulse at $55. This will give whatever speakers you choose more mass, tighter bass and clearer vocals etc.

Speakers, 6.5″ is the format so you have a vast range to choose from. I would strongly recommend using the same series of speakers front and rear, it makes a lot of difference. Using the factory speakers in rear doors is a no-no. Even if no-one sits in the back ever, it still matters. They will invariably be out of phase with the front speakers at various frequencies. If you can’t afford to buy matching front and rear speakers, best to disconnect the factory rears, they are interfering with the new front speakers.

Let’s look at the ranges: Auditor is the entry level, Access is two up, Flax is next, then Elite K2.

Matching front component speakers and rear co-axial in each range, at 2020 prices:
Auditor RSE-165 $209  RCX-165 $169
Access 165AS $349  165AC $249
Flax PS165FX $629  PC165F $399
Elite ES165KX2 $1099  EC165K $575
 
Add the amp and its cable kit $414 and you have a pretty good system. Obviously the higher up the speaker ranges you go, the better will be the results, but even a basic Auditor kit front and rear, without the amp, will be an improvement on your old speakers.
 
If you can afford, lining the doors with a sound-absorbing material like Focal BAM will significantly improve sound quality of any of these speaker ranges. BAM works by absorbing the back-wave from the rear of the speakers which interferes with the sound from the front of the speakers. Don’t confuse it with sound-deadener which has the principal purpose to stop door panel vibrations. BAM does that also, but it has a soft surface that absorbs sound waves.
 
I hope this helps.

Can you give me any clues on where to install my speakers for best sound quality?

Try to mount your midrange speakers on a wooden panel if possible, or at least on a solid surface. A lot of good installers cut out MDF panels for every speaker. This ensures a few things: a good air seal for the speaker, it avoids buckled frames, and it addresses the issue of spill. Don’t raise the speaker above the surrounding panel with those little speaker spacer rings if you have the option to make a small MDF mounting panel. This need only be a couple of inches bigger than the speaker.

Don’t use tweeter ‘surface mount pods’ if you can devise a way to recess mount the tweeters into the doors or into a fibreglass or body putty custom mount. I have heard some good results from mounting tweeters at the base of the A pillars. This will involve making up a fibreglass or body-putty moulding on the A pillar. The mirror pods are probably second-best position. The mirror pod is the easier position to mount tweeters on, the A pillar gives better sound quality but will cost more labour.

If you are shaping up a tweeter mount using fibreglass or bog, try to create a flat area extending a centimetre or two around the tweeter. This reflects the ‘spill’ from the tweeter out toward the listener.

The aiming of the tweeters is also important. They should aim across the car at the opposite front seat headrest. In other words the passengers side tweeter should be aimed at the drivers head and vice versa. If you pay attention to these details you will get 100% better sound quality.

When people complain that their tweeters sound bright and intrusive, you can bet they have broken one or all of these installation rules.

Adjust the crossovers at installation, then again two months later. If you have installed tweeters at or above dash level, turn the level down a little with the adjustment switch inside the crossover. The KP and K2P range have eight tweeter level settings inside their crossovers, the other Focal ranges have three, so you should be able to find a setting that suits you.

There is a principle that tweeters and mids should be in the kick panels to get them equidistant from the listener. It sounds great in principle, I can never deny the theory is absolutely correct. The problem in practice is that your legs obstruct the sound. Kick panel mounts sound best if you sit with your feet tucked under you. Another important principle is that woofer and tweeter should be within fifteen inches of each other. Technically correct again, but it’s not always possible without rebuilding the whole door panel, an expensive operation.

Don’t expect to get a carefully planned tweeter and speaker installation for $100, it will take someone half a day to build-out A-pillars or mirror mounts, fit the tweeters and then re-skin the panels in new vinyl. Unless you are a whiz at motor trimming, be prepared to pay for an expert to do this.

Most car radio shops won’t volunteer to do A-pillar installation of tweeters when they sell you the speaker kit because the cost would scare most customers away. If you’re after hi-fi sound, you’ll have to ask for specialist installation, be prepared to pay the money.

Factory tweeter mounting position in many new cars direct the tweeter against the windscreen glass. It’s an absolute no-no in home hi-fi to point your tweeters anywhere near glass and the same applies in your car. Reflected sound off a windscreen is not going to be good.

Focal put a lot of research into designing tweeters with a linear sound output. If you install them right, you’ll reap the benefits.


I have 130V slim speakers in my car as that is all that would fit, I was expecting more bass…

All slimline speakers lose out on the bottom end. It’s a function of the cone shape, a wide angle cone doesn’t play bass as well as a conventional shaped cone. That’s why flat panel speakers never caught on, they play beautiful midrange but little bass.

Limited bass is the price you pay for having to use slimline speakers and it applies to all brands, it’s not peculiar to Focal.
Don’t despair. 5″ speakers play beautiful midrange such as guitars, vocals, saxophone etc. Few people realise that 5’s are vastly superior when reproducing that part of the sound spectrum, compared to the more popular 6″ and 6.5″ speakers.. Everyone is looking for the speaker that does everything, and they overlook the 5’s. In simple terms, the cone of a 5″ is much lighter than that of a 6″, therefore it can change direction easier and it can follow the music more accurately.

There are some cars which just don’t have space in the doors for anything other than a slimline speaker. You might be able to get a good car radio shop to build you custom door pods to hold the full-size speakers 130V2. Many things are possible when the customer is prepared to pay for the time and materials to modify door panels to accommodate better speakers. However some cars are just impossible to fit anything other than a slimline speaker.

Some car manufacturers have strange ideas about speaker locations. Some speakers face forward and down, toward the drivers and passengers ankles. Others face into the laps of the driver and front seat passenger. Other cars have only a fifty millimetre speaker mounting depth. Until car manufacturers wake up and start to think about speaker placement, there will be plenty of work for good car radio shops.

If you have to use slimline speakers it’s a good idea to use a subwoofer.

You might consider an 8″ subwoofer such as 21V2, which will take up minimal boot space and needs only a small amplifier. This will give you excellent sound quality and good bass extension.

Another possibility is 11″ version, the 27V2. This compact sub sounds tight and fast. It’s not a subwoofer to show off with, it’s a subwoofer that you don’t know you have until the music hits a low note and it just takes over the show for a second or two, and people say ‘what the hell was that? I never heard that part of this track before.’

A simple system with 5″ front speakers and a good little subwoofer can be a lot of fun, and it’s a perfect for a small car.

The 33KX will be much more impressive than27KX, they have a much bigger cone area, therefore they play louder than 27KX. Also, they play lower by around 5 Hz, which is quite a big measure in subwoofers.

If you face them forward, they will be tighter-sounding and less ‘boomy’ than rear-facing subwoofers. An ideal solution would be to manufacture fiberglass boxes for each back corner of the boot. The extra distance from the listener gives a longer path-length for the bass to develop so ;it will be deeper and louder. The sound will achieve a boost as it is fired from the back of the vehicle along a ‘passageway’, it’s as if the sound was being fired from a cannon, it’s concentrated toward the front of the vehicle. This installation method will leave you with less vibrations in the boot area, less number-plate rattle, and harder-hitting bass.

The fiberglass boxes should be constructed so that each driver faces forward diagonally, aimed approximately at the opposite passengers door. The boxes themselves should be lined with sound-deadening material such as Dynamat or Road Kill. This makes them more rigid. An extra enhancement to the bass would be to line each sub box with as much Focal Plain Chant as you can afford. It’s expensive but it makes a huge difference inside a sub box. Its purpose is sound absorption. It creates a ‘black hole’ for the sound created by the rear of the subwoofer cone, thereby cancelling reflected sound and standing waves within the sub box.

This is the most expensive installation option but it will give the best bass and leave you with plenty of boot space. If you’ve bought op-quality equipment, don’t cut corners on the installation.


How To - Set-up my Focal Solid Amplifier

Setting the amplifier gain

Settings are optimised on the Solid car amplifier range. The principle is the same for the majority of Car Audio quality amplifiers. This table explains the simple procedure to follow for optimal amplifier gain setting.

Necessary equipment:

  • Voltmeter (AC setting)
  • Focal Tools or frequency test CD (supplied with all Solid and Focal Power Symmetric line amplifiers).

Procedure to follow

  1. Disconnect your Car Audio amplifier from your speakers.
  2. Adjust the gain to the minimum setting.
  3. Start your engine.
  4. Check whether your car radio is in its original configuration: bass/treble at 0, balance/fader in the centre, equalizer on FLAT and set at three quarters of its maximum volume.
  5. Insert the Focal Tools CD – a. Solid 1: Adjust the cut-off frequency to 150 Hz – Track 14 (50Hz); b. Solid 2 & 4: Set to Full position – Track 27 (1kHz)
  6. Connect the voltmeter to the output terminals that you wish to set.
  7. Gradually increase the gain until you reach the reference value in the following table.
  Solid 1 Solid 2 Solid 4
Channel 1 1&2 1&2 3&4
30V 16V 16,5V 16,5V
26V 24V 14,7V 14,7V
Bridgé 4Ω   26V 28,5V 28,5V

I'd like some advice on setting up Focal Kit 7 Active three-way speakers using my old six-channel amplifier in place of the UNIQ crossovers. I'm doing the installation at home to save money, also there isn't a Focal dealer nearby. Alternatively, I could use the UNIQ crossovers, bridge four of channels on my six channel amp to achieve more power, and have two channels remaining for the rear speakers.

Yes it is possible to use your old amp in a fully-active configuration, however I urge extreme caution. I’d suggest you leave the installation and tuning to an expert installer, even if it means a long drive . There are many subtle design features built into Focal UNIQ crossovers which you will be bypassing if you use active amplification. The failure rate of speakers is much higher when using them without the factory crossover.

I’d draw a parallel to installing an after-market engine-control module into a new car. The car may perform a little bit better in straight-ahead acceleration but many other functions don’t work as well as the they normally would, for example gear changes will be rougher, the idle will be rougher and the car will chew through fuel and exhaust filters.

The genuine Focal crossovers were carefully designed to restrict the individual speakers to certain frequency bands, compensate for phase shift at the crossover frequencies and balance the outputs of each speaker appropriate to an overall sound. Engineers with years of university education have spent a lot of time designing these things, so to double-guess their design would be a case of hit-and-miss. Bear in mind that should you burn out any of those 6″ Utopia speakers it will cost you $415. There is no warranty on speakers with burnt voice-coils.

Your entire Focal Kit 7 could run quite happily on a good amplifier of 60 watts RMS per channel. Amplifiers with higher power ratings are also okay, a bigger amplifier is probably a wise investment as that amp will be idling, not stressing out. Speakers don’t burn out by themselves, overworked amplifiers tend to pass the stress along to the speakers in the form of clipped signal and it’s clipping which releases the smoke from the speakers. An amplifier with plenty of headroom is always safer than an amplifier too small for the job, and you’ll get better sound quality as a bonus.

Whatever you do, don’t bridge an amplifier onto any speakers other than a subwoofer. The sound quality deteriorates noticeably whenever you bridge an amplifier. Considering the speakers you are using, which are very revealing of any weakness in the system, bridging an amplifier to get more power is a definite no-no.

So when it comes to recycling your old six-channel amplifier in this new car, I’d suggest you start again and buy the right amplifier for the job, an FPS4160 four-channel amplifier. Use two channels to run the Utopias through the UNIQ crossovers, the remaining two to power the rear speakers. Sorry, no matter how high a quality your old amplifier may be, if you have to bridge it to make use of it, you are defeating the purpose of buying excellent speakers.


I have some great sounding (brand X) speakers from my last car. Would these be okay to use in the rear of my new car with my new Focal 165WRC in the front?

No, you should never mix up speaker brands and series within the one car. Always use the same series speakers front and rear. If you use Focal K2 Power in front, you should use Focal K2 Power in rear.

It’s to do with cone mass and magnet material etc. If the speakers front and rear have similar characteristics, they will move in time with each other at all frequencies. If you use speakers of a different series, even if from the same manufacturer, they will be ‘out of phase’ with each other at certain frequencies causing some blurring of the music.


How do I adjust my Focal iBUS20 for the best sound?

We would suggest as a starting point:

  • Subsonic at 35 Hz,
  • Bass Boost at 6
  • Low pass at 80 Hz

What is active configuration?

Active configuration is when each individual speaker, each tweeter, each midbass driver, is powered through a separate amplifier channel.


Why do people consider it is superior?

It’s a bit of a myth promulgated by online chat and blogs, which are usually run by weekend experts. In the hands of a very well educated installer, with a lot of high-end test equipment on hand and the skills to use that gear, you can get sound quality improvements. The level of improvement achievable relates back to how cheap and nasty the factory crossovers were.

With most European speaker brands a lot of design work went into the crossovers so you won’t get a big improvement by second-guessing the manufacturer, trying to do an active system with just an amplifier and the inbuilt crossovers.

In as few words as possible, use the crossovers that came with the speakers. Do not bridge amplifiers onto any speakers other than a subwoofer. These are the two commandments of car audio. Defy them at your own risk.

To do active configuration properly:

  • you need to sell the customer a sound processor (Focal FSP-8 for example: $899 retail)
  • you need to know the design frequency range of each individual speaker
  • you need a machine called a Real Time Analyser (RTA) to analyse the output sound
  • you need an oscilloscope to check for clipping of both input and output signal
  • you need training in which crossover slopes to use in which situations

Customers will come in and try to bluff you into taking their job on, as an active installation.  The risk of damaging one or multiple speakers are great. Best to avoid the job if you don’t have the equipment and training.

A signal processor and an active configuration in a car stereo system can give significant sound improvement because the installer can make compensations for frequency response dips caused by the vehicle interior or various components in the audio system. However selling a processor is fraught with dangers unless you have the above equipment and know what you are doing.

If you really want a noticeable improvement with minimum fuss, sell the customer on sound-absorbing sheets (Focal BAM etc). Don’t confuse sound-absorbing with sound deadening material. Sound absorbing material has a soft rubber surface to absorb sound waves. Sound deadener has a shiny surface and is a reflector for sound waves, so it causes more trouble acoustically than it fixes. Lining the doors with sound-absorbing material will give bigger bang for the buck than wiring speakers active configuration.

Keep it simple. Don’t get talked into active wiring setups. Better to let them go elsewhere if they insist, it’s just going to end in tears.