Before starting off with the DIY story, let me clarify a couple of things…
 Every DIY has its own inherent risks. I considered the ‘worst-case-scenario’ and decided that if I ended up with damaged speakers / blown HU or Amp, I was ready for it. [Acceptable risk]
 I have been using the setup in my cars since 2002, first in a Santro [with the rear-speakers running off a single Sony XM222 – 2 channel amp], then in 2004 the system was transplanted into a M800, then in 2005 the system was transplanted into the Xing, and an extra amp was added. Over the past 6 years, the speakers have worked great.
 My initial concern was around degradation of the speakers due to heat, since my car would be parked in sun for long hours. The only precaution I would take was to cover the speakers with a cloth to prevent direct sunlight from falling on them. They continue to work fine till date, so I can say that this is a ‘tried and tested’ DIY.
 The longevity of the speakers, the performance of the system etc. may depend on what you are starting with and how well-made the speaker boxes are etc.
 The only damage I have experienced is that one of the speaker metal grills is slightly dented due to a suitcase being placed on it. [No change in sound quality though]
 Before embarking on any similar DIYs, just ensure that you get the full tech specs of the amp / HU in your car and the ratings of your speakers to ensure that they match. [Look at the RMS, Impedance ratings etc.]
 Before I give the car for service, I disconnect and take out the boxes.
 Once every few months I use a vacuum cleaner blower to blow out dust from the speaker cones. [Not at full blast, might damage the speakers, I reduce the wind speed with a gauze / mesh cloth.]
How does the system sound?
 Sweet! Really sweet!!. Since the rear speakers are full-range speakers, with built in cross-overs etc. the sound quality is quite good throughout the volume range that I use.
 The bass is quite good, without the ‘dead-bass’ beats that come from a sub-woofer and powerful enough to require some mild-damping.
* See my DIY damping story. : A DIY (Damp It Yourself) story: DynaMat, FonoMat…Yoga-Mat ????
[I avoid sub-woofers since I tend to get a headache after a few minutes of being subjected to the ‘dead-bassâ€™ frequencies.]
What kind of music do I listen to?
Everything – from Bryan Adams to Eminem, Bhimsen Joshi to Jagjit Singh, the latest Bollywood hits to the old Hindi classics, KennyG to Infected Mushroom… so the system has been tested for almost all kinds of music.
Now for the DIY story…
Think about it, for an average Joe like me, buying a decent home audio system is a relatively painless exercise. Just walk into any good electronics store and I can walk out with a system that suits my budget and taste. Be it a Sony, Philips or a Samsung, they all make complete and ready-to-use systems.
But look at a typical car audio system buying exercise; first choose a head-unit, Pioneer or Sony or Blaupunkt or XYZ. Then choose the front speakers – components or coaxials? Next move onto the rear speakers – there must be atleast 100+ options available on JC Road, in all shapes, sizes and brands.
Other decision points include – should I just connect everything to the HU or should I use an amp? Do I need a sub-woofer?? Adding to all this complication is the fact that for every original component, there must be atleast two counterfeit ones in the market. With all these variables thrown into the equation, will the final result be what I want? Depends on luck I guess… lots of it.
When I got my first Santro in 2002, I did a lot of R&D, checked out all my friend’s cars and then finally went JC Road thinking that I was ready to get my car ICEd. After deciding on the HU, I got a pair of Pioneers fitted in the front. Now the crucial rear-speakers, I bought a pair of Sony ovals (The pre-Xplod series).
Since I did not want to sacrifice on the usable boot-space and did not want a rear plank either, I got a pair of slim ‘side-boxes’ fitted in the rear – the kind that fit on the wheel arches. All connections done and system switched on… and it sounded really crappy. I had used better sounding ‘2-in-1s’ in the past! 🙂
The dealer suggested using normal boxes and adding an amp, a Sony XM 222. That done, the sound did improve a lot, but I was still not satisfied. The next option was adding a plank, the system sounded decent with the speakers mounted on the plank. Since it was already past 9.00pm and I was quite tired, I decided to call it a day and returned home, with a not-so-happy feeling.
All the way while driving back I was thinking, why don’t these audio companies make good and easy-to-use car audio kits? Give me a good HU, with matched front speakers, a decent amp, rear-speakers pre mounted in good boxes – designed specifically for each popular car model. Throw in all the different wires and connectors required and you have a ready to use kit. [Sony / Philips, are you listening?]
For the next couple of months I drove around with the system, all the while thinking that there should be a better way of doing things.
I had a Sony MHC-VX501 HiFi system at home that I was not using much. The system has an amplifier rated at 120w +120w RMS @ 6ohms. The speakers are SS-VX333 boxes, 3-way, 3-unit bass-reflex type [See the spec sheet for full system details. Sony systems normally have a tendency to be ‘Bass-rich’ and the same was the case with my HiFi. Since I was catching up on my music more during my commute than at home, the system at home was under utilized.
One day, I was wondering about what if I use the Sony speaker boxes in the car… was it possible? I pulled up the spec sheets for the speakers and the car amp and the numbers looked decent. The single amp would still be quite under-powered compared to what the speakers could take, but it should work…
Went down to the car, took out the plank, placed the boxes in the boot, connected them to the amp and viola! it sounded good!!! The main argument against using home-audio boxes in a car seemed to be whether they could take the heat and vibration. Considering that the speakers were not being utilized fully at home, I thought that even if they last for a year or two, it should still be ‘paisa vasool’.
As mentioned earlier, the system worked flawlessly in the Santro from 2002 to 2004. Then I had a M800 for about a year in the interim, the system was transplanted and worked fine… when I got the Xing in 2005, the system was again transplanted. This time a second amp was added for more juice. Since the XM222 amp was not available, I picked up the nearest alternative, the XM502Z. Currently each amp is powering one rear speaker in a bridged mode. [The HU rear-speakers selection is set as ‘full range’ and the band-pass filters on the amps are set to ‘off’]. Recently I changed the HU to a Pioneer 6050UB since my previous HU did not have USB connectivity.
The front speakers are JBL GTO426e 4" 2-way units, fitted into the stock receptacles, running directly from the HU.
I got the amps wired as follows; the left rear channel from the HU is split into two using a ‘Y’ type RCA splitter cable, fed into the left and right channels of the amp and the speaker is connected in a bridged mode. [So both the channels of each amp are getting the same input.] Similar setup with the other amp. [See diagram below in this post for clarity. Why this type of wiring? It sounded better than running just one input into each amp in a ‘bridged’ input mode. i.e. like when a sub-woofer input is connected.]
There are also a pair of JBL CS265e’s fitted in the stock speaker receptacles in the rear. On rare occasions where there is a lot of luggage to be carried in the boot, I take out the speaker boxes, put in the detachable plank and switch-over to the JBLs.
I had thought of fabricating some sort of fasteners / Velcro belts etc. to hold the boxes in place. But each box weighs 4.3kilos and they donâ€™t move around, so no fastening required. I have placed them on a thick cloth / mattress.
Currently I am quite happy with the system and see no need to change it in the near future. Though I did consider picking up a more powerful 2 channel amp, it has not moved from â€˜wish-listâ€™ to â€˜action-item listâ€™ as yet.
Specs & Pics of the DIY:
How things are connected…
The speakers are normally placed like this…
The speakers look like this when placed upright…
The XM222 amp under front driver side seat…
The XM502z amp under front passenger seat…
The front speakers…
Full Tech specs…
Just in case you are wondering what happened to the Sony Music System after the speakers were taken away. Well, the system is still in use occasionally… it is connected to the DVD player for use as a home-theater setup. It now sports a pair of Jamo E370 floor standing tower speakers.
Another small experiment with a Powered Sub-woofer:
I had a unused Sony Powered Subwoofer box lying unused and on a whim I wanted to see if I could fit it up in the car.
First thought was to see if the inbuilt amplifier from the sub-woofer could be used.
Option 1: Using a DC-AC (12vDC to 220vAC) converter box – The type which can be connected to the cigarette lighter socket in the car and used to power laptops and chargers etc. (They are available at Staples / Croma / Reliance TimeOut & also as Hyundai Accessories.)
But I discarded the idea since it would involve another 1800/- expense + the charger may not be good enough to be used for long periods and also I did not want to add more load on the car power supply.
Option 2: Since most household electronics run on a DC current (18/16/12/10 etc. volts) – There is usually a AC-DC transformer inside most HiFi systems to convert the 220v AC to a 18v/12v/10v DC.
I opened up the Subwoofer to take a peek. There was no mention anywhere of the exact DC voltage that the SW amp circuit was working on. So I noted down the part number of the transformer and some of the other components.
I Googled around for Sony part number specs and found that it was indeed a 12v transformer. Which meant that I could bypass the transformer and look at directly powering the SW from the car 12v power supply.
But I discarded this idea too since I would have to get additional wiring done to power the SW. Also, though the voltage was 12v, I could not get the full specs for the transformer, so I was not sure if the SW amp circuit would survive being powered from the car battery etc.
I thought it was too risky to try since the amp circuit may fry and do damage to the car wiring etc.
Option 3: This was the option I finally used for the test and it worked perfectly.
I just disconnected the Subwoofer amplifier circuit totally from the subwoofer speaker and ran wires directly from the speaker leads. The sub-woofer speaker was rated at 6 ohms. So I could just use a normal car amp to power the SW.
My car already has 2 twin channel amps and I am using each one separately in a bridged mode to power one rear speaker each.
I switched the wiring a little to use one of the amps to power both the rear speakers.Hooked up the other amp to the sub-woofer output from the HU and connected it in a bridged mode to the subwoofer box, which was now just a ‘passive subwoofer’.
Switched it on with my fingers crossed and it worked just fine!!!
I used the setup for about a week before taking it out and reverting back to my original setup.
If it worked fine, why did I take it out?
 I like ‘crisp’ bass. Where each beat has a punch and a sharp ending. The sub-woofer added a lot of low frequency bass, but it was the sort of sound where each beat would have a deep thump but the crisp ending was missing… and I preferred the older sound.
 The boot space in a Santro is limited and the additional SW box occupied more space.
 The Sony boxes that I use produce more than enough bass and sound best if powered by one amp each. (The amps I have are not all that high powered to optimally drive the rear speakers in a two channel mode.)
So if I wanted to continue with the subwoofer in the car, I would have to either buy a separate amplifier for the SW (car would have 3 amps!) or buy a more powerful 2 channel amp to power the rear speakers and use one of the older amps with the SW.
To summarize: The experiment worked and was tested for around a week. It added to the sound pressure level, but the sound quality level was not to my taste.