2009
11
This is something which plagues you from the time you buy a vehicle. Most of us try to find that elusive ‘awesome’ sound quality and in 90% of the scenarios, we fail. To start with, we base our primary objective wrongly. Considerations start with the following factors in mind:
- Cost
- Wattage / PMPO
- Playing multiple media types
- Phone integration
- What fits in the car? Single or Dual DIN?
To name a few.
A dual DIN head-unit from Kenwood
A single DIN head-unit (Kenwood iPod Series)
Cost
This is of prime importance and one should limit the cost of the product else one can land up with a vehicle which has a more expensive than itself stereo system. Think about it this way, if you just want a good stereo, get it for your home. A reasonably good car stereo is much more expensive than a very good home audio product. If you have the cash, get a larger car, probably a great stereo will come with it. In case it did not, we move to the next point..
Wattage / PMPO
Wattage of a stereo amplifier is the measure of energy it is generating in the form of sound / music / audio / noise. PMPO is a measure of nothing and is used by marketing gurus to empty pockets of the unsuspecting consumer. Picture this, a 10,000 W PMPO Amplifier in your car. Question the fact that where is all that power coming from, since its way past a commercial establishment’s requirement. The PMPO is a tentative measure of how loud the stereo amplifier can get. (Will leave out Monaural / Mono audio as we have gone past that barrier about 80 years back, successfully.)
Advice is: Do not go by any PMPO value advertised.
Ask for the RMS value for the same. That’s pretty much the actual measure of how much audio will be produced. For a car, 50W to 100W total is good enough.
Playing multiple media types
So what would you finally play on this gadget you purchase. Any of the following:
- CDs
- Audio Tapes
- MP3 Files from Data storage
- MP3 Files from CDs / DVDs
- DVDs (Video and Games)
- VCDs (Chinese version of a video disc)
- Connect your MP3 player like iPod etc.
- Connect your phone with Audio in it
- Navigation System
Chances are, you will want all of it. Once you get all of it, here’s what you will finally use. The FM Radio, the MP3 Player / Data connection and the occasional CD. Lets face it, it’s outright dangerous to watch a video while driving, so the DVD will be used when you are in the car and have got nothing else to do. Chances are unlikely unless you moonlight as a Chauffeur. The same goes for VCDs no matter how cheap they are, you still need your eyes (off the road) to watch them. As far as audio tapes are concerned, well they are in the past. Some old tapes you may have, which I would suggest you listen and cherish them carefully on a proper Tape Deck at home. Anything new is all MP3 and CD.
A dual DIN DVD player with an in-dash screen from JVC (http://mobile.jvc.com/)
Phone Integration
Phone connection may be an advantage for people who drive a lot and get calls a lot. Still, a standard hands free set fitting into the ear is much less cumbersome than a stereo that has to be paired every now and then. Also, imagine you are travelling with 4 other’s in the car and the phone rings.. what do you do? Not to mention if its your secret ‘other girlfriend’ you are in great danger of a collision of a different kind. Avoid.
Navigation System
Navigation Systems only make sense if the supplier of the Map and directions is reliable. In most cases, the Nav System gives you the shortest possible route, and not the best possible route. An important component nevertheless. One should probably note that a Standalone Navigation System comes a lot cheaper than an Integrated with Stereo one. Plus, you can shift them from one vehicle to the other if need be.
A Delphi NAV 300 installed in a car
This pretty much narrows down the sensible scope of add ons to a CD player which reads MP3 and has some kind of input to play external MP3 players. Which brings us to a different kind of a problem, do we select an Auxiliary Input or a Direct USB Input? The auxiliary input will definitely be cheaper and will have almost no quality difference it terms of playback as compared to a direct USB interface. Here’s what will have a difference, the ease of use. In case of an Auxiliary Input, every-time you want to change a track / song, you will have to hunt down the every diminishing sized MP3 player and then change the song. With any luck you would not have collided with the next jay walker on the road. In case of a direct USB interface, it ’s the same button on the CD player which is at a pre-determined fixed place. Operation is smooth, without danger, and over time you will not have to grope the dash either thanks to our “Muscle Memory” (The same biology stuff that helps us remember the difference between 2nd and 4th gear.
What do we have till now!
We have a headunit (the stuff that sits in the dash) which plays a CD, tunes to FM, connects a MP3 player through USB, and probably displays the number of the person calling you on the phone. But this is just 25% of the drama. The rest begins after this.
Sound Quality and Wattage
We have finalized on that we are doing with the stuff on the dashboard. Now it’s time to see what can be done with the stuff you do not see. Before we get into the whole issue of how much wattage and how much quality, we need to look at one important factor, that is how many speakers can be fitted in the car. Most headunits will come with the provision to plug in 4 speakers, but most cars wont. So search for all the provisions to fit speakers in your car, chances are there will be at least 2. Start with them, find out what size of speakers an be fitted into them.
- Small Cars: 4″ (2 speakers)
- Little larger hatch backs 4″ or larger (4 Speakers)
- Larger mid size vehicles 5″x7″, 6″x9″ (4 Speakers)
Now that we have a value, for the above, we can go looking for the wattage that we actually require to power these. By thumb-rule, smaller speakers are best driven at lower wattage. The wattage a speaker can handle at the maximum will be rated and printed on them. Along with that, there will be the impedance value (load the speaker puts on the amplifier, higher the value, greater the load). This should land you with a set of speakers that have X wattage and Y impedance. These have to match exactly to the X and Y of the head-unit, if they do not, the joy is short lived. There is provision for a marginal variation in terms of wattage but variations in terms of impedance is a definite “No No”.
This more or less sums up a decent stereo system for a car. If you manage to get higher wattage in the size available for the speakers, you can get a head-unit that pumps out more power. Higher the RMS, better the sound depth (not quality)
So what will give quality
The answer is simple. Money. Higher end audio products (head-units and speakers) with lesser RMS power output will sound better than lower end average like Sony or Kenwood. It is better to get the speakers and head-units from the same manufacturer as they tend to match and gel together better. Like a marriage between two Chinese people or two Indian people. Mix and match is risky in quite a similar kind of way, do not attempt unless you have a lot of cash to burn. Mix and match can either sound excellent or can be a pure recipe for disaster.
Lets go back a little. What IS sound quality?
No, it’s definitely not how loud the system sounds, its more of ‘how true and natural’ the system sounds. Depending on your taste of music, get a file of Tabla, Dhol, Drums, etc. A Safri Duo track will be an ideal choice. Lots of drums and beats. Once you have this track, play it. It should sound like the drums are tight and not like a ‘bucket being bashed up’. (For this you may need a reference point of actually hearing a drum, but human ears do not lie) A tell-tale sign of a base heavy system is that the reverberations remain even after the beat (much like a speaker in an Autorickshaw), avoid this at all cost.
Get something that does not retain a humming effect. This gets irritating when the stereo is on for longer durations.
Next is, how good the human voice sounds. The best tracks for this is anything by Lata Mangeshkar or Whitney Houston. Both are masters of their craft, different genres but similar octaves. If they sound good, chances are the rest would too. Most music systems get very shrill while trying to reproduce these two artists, the objective is to have them sound like artists and not a ‘machine’. Most music systems also crackle a lot when female vocals are played loud.
But how do we test this. Well, chances are the dealer will have some sort of a demo in place to test drive the Head-unit and speakers that you want to go for. If you have OEM speakers (Factory fitted in the door, boot, window, parcel tray), then just test the head-unit with multiple speakers. If the head is fine, the rest will sound good as well.
Now that we are set with the Sound Quality part, we get to LOUDNESS
Its a matter of choice, how Loud is Loud Enough. What is Loud for me may or may not be loud for you. We go back to our Basic RMS jargon and up the values. The higher the values, the louder the system gets. It is a good idea to first fix speakers with the largest (or desirable) RMS values. Remember that larger speaker have larger RMS values but there may not be the place available to put them in your car. Do not go for drilling, cutting etc of door panels. It’s a fools errand, things will start rattling before you know it and Money for Nothing, will play more of the window than of Dire Straits. Most music systems available in the market start at about 50 RMS and end at about 80 RMS (total). If you want to go on beyond this, you need to plug in a power amplifier.
Power Amplifier
These are god send devices for audiofiles, those who want more depth in audio in their cars. A typical Power Amplifier takes the audio signal from your head-unit in it’s native form and amplifies it further. Power amplifiers can take the output value to about 100 Watts of RMS per channel. Since there’s not much place available in the dashboard, these have to be fitted in the boot, under the seat etc. and the cables have to run under your floor carpet or ducting.
Note that the power amplifier can get very very hot with prolonged uninterrupted use and fixing them anywhere near the fuel tank is not a good idea. The units also carry a lot of high voltage and a short circuit within can spell disaster.
The ideal place will be to put them under the driver’s seat, or the co-passenger’s seat. Mostly they are available in black and stay out of the view. Installation will require an expert hand as drilling and bolting may be involved.
Subwoofer. What is this?
A step up in the Power Amplifier area are the Subwoofers. There are three kinds that are available.
- A type that needs a separate power amplifier and is placed in a hole on the parcel tray.
- There are those that do not demand cutting and have a large baffle (box) of their own, but still needs a separate amplifier.
- The third type, that has the amplifier, baffle (box) and speaker in a single unit.
The third type is the most preferable. The first type involves unnecessary cutting of original equipment and fitment. After market fittings are never rattle free. The second type is Ok, but it still needs an amplifier to bother with. The third type is the most hassle free and kind of plug and play. In most cases, the 2nd and 3rd types are mostly places in the boot (eating your precious luggage space). Thinner are slimmer varieties are available, which can be fitted under the seats to retain valuable boot space.
But it’s the second variety that sounds the best out of all of them. In this case, the box (baffle + enclosure) plays a major role. A base reflex type will save you further on space. Most brands like Kenwood or Blaupunkt have reasonable good subwoofers, but these are no match for a Velodyne. (Class A home theater grade Subwoofer).
A non enclosed subwoofer from Pioneer
Given the size of your pocket, and willingness to spend, you will land up with something that's schematically like this.
High pass and Low pass
Most amplifiers and head-units will have High Pass (let high frequency or ‘mid and treble’ pass to door speakers) and Low Pass (let low frequency or ‘bass’ pass to Subwoofer). If the one you selected does not have that, change your selection and get one which have. In case you are putting extra amplifiers, disregard the High – Low pass on the head-unit and set the same on the amplifiers instead. By Bridging an amplifier, you can direct all power to one speaker and use one amplifier for each door. This is a very rare thing to do in a car, and you will definitely run out space to put 5 large amplifiers. Not to mention the amount of current they will consume from your battery. Amplifiers used for the Subwoofer are mostly bridged to give it more power.
All these fitted in and you are almost done.
Set the head-unit equalizer values to suit your ear and car (keep them at 0 – 0 till this point of installation), if the Subwoofer and Amplifier sets you bought have high pass and low pass settings, set those as well. Get your favorite CD / MP3 and gun the system. Not too loud, just about 25% of its available power. Most amplifiers will only sound good till about 50% mark of their peak, after this they run out of steam. (Unless you are using a really high end one)
The next important thing is to find a good long road. But that’s another story.