Basic Information on In-Car Entertainment (ICE)

[jayadev]

basics to advanced

if anybody asks me what is most important factor in good audio setup in a car?

cables!!!

if you have 1000 watts of power amplifiers the cables should be able to withstand that much amount of power.

the battery of a car is 12 volts
power = volt x currents (ampere)

1000=12 x ampere
1000/12= 83.3 ampere

imagine if your power amp is in the boot so considering the car length to be 4meter and cabling harness extra 2meter, you need 6 meters of total cable which can deliver 83 ampere at 12 volts!!!
anything less means you are compromising seriously!!

so you choose the guage of cable accordingly.

hope you get it that just any kind of cable kit available in shop is not going to show you the path of nirvana.

 

[jayadev]

now the question , what is the requirement?

1.just clear music and with melody (100hz-20khz):- generally stock head units and speakers would be alright ,just fiddle with he audio options in the hu you can get more juice.if not, just upgrade to better speakers that will help in most cases.

2.gut-wrenching bass to knock off the people on the road(30hz-20khz) :- there is plethora of options with a good range of amplifiers and woofers in market. most probably
400watts amps for left and right coupled with above 600watts for subwoofer is just the beginning for that.

3. earthquakes,thunders and glass shattering(15hz-30khz) :- well you have to see a sound engineer(car sound engineer) with electronics background (with loads of patience. )

 

[jayadev]

i think designing and building part of ice is not necessary here as it would be a boring procedure and many won't appreciate it. so lets move on to something else..

 

[jayadev]

so ,

more number of speakers more sound , more power ,more value , more people say wow!!!

well that is not how reality is!!!

each speaker is producing sound along with certain amount of colouration or distortion in sound ,even though very much negligible but they do it. as its all happening out of vibrating cone of speakers. so what happens is
more speakers more sound more distortions...how?

well each speakers produces individual sound or waves and depending on wavelength they crisscross each other producing superimposed waves or harmonics. that is where harmonic distortion leads the role.

often you pay more for more number of speakers and amps with bunch of freebies called distortions they follow you like ghosts if not treated by a knowledgeable guru they are going to haunt you like hell !!!

what all happens if ghosts haunt your speakers. have alook or read on

bass thumps would sound puff puff instead of boom boom.
cymbles and guitars would sound like vessels and utensils banging in kitchen.
romantic vocals would sound angrier or sad..so and so ..
whole sound reproduction may get disturbed depending upon the setup which may vary from 0.001 percent in high end systems to 50.0percents in cheap bargain setups.

 

[avindu]

Wow! Wonderful thread Learnt so many new things today!

Just a clarification - About the Head Unit's "output voltage", guess, the minimum is usually 0.5 volts but 2 volts and above is common in high end units. So, higher the output, lower the noise?

 

[Zinam]

Yes, The higher the preout of HU, greter the clearity & lower the noise levels.

But it also counts on the hardware specs of Preout, like 7200MK II has gold plated pre-outs which creates very less disortion.

 

[jayadev]

Yes, The higher the preout of HU, greter the clearity & lower the noise levels.

But it also counts on the hardware specs of Preout, like 7200MK II has gold plated pre-outs which creates very less disortion.

gold plated connectors is good as far as corrosion is concerned gold remains immune to it. you might not be surprised if i say 100 percent of electronics are soldered which is nothing but metals known as lead and tin.
100 percent of all circuit boards in any electronic component consist of copper circuits and conductors.
so gold plate on outside adds negligible to nothing in overall quality of a component but the corrosion ,gold plating remains clean and conductive for longer duration and of course aesthetic part also cannot be overlooked.


higher the preout of HU, greter the clearity & lower the noise levels.-apparently or practically it sounds right but the grass greener on side is not always safe.

what if the amps were designed for lower level of sound signals (high sensitivity).
what if high voltage preout is is throwing high levels of noise also.

truth is there is nothing much relations between high pre-out or lower noise.
fortunately all those exhorbitant head unit have faithful high level preout.
but basically noise and clarity begins from the source of sound itself like cd,usb,dvd,radio or whatever. if the initial source had some issues it will be multiplied or amplified proprtionately.
but if the head unit had no proper or good noise handelling no matter how high the preout is the noise will be evident.

the notorious ones to add noise and distortions are digital to analog convertor if they are not much reliable one included in any given circuitory not even god can help for good results.
then comes the sound enhancements like bass treble boosters, equalizers, surround and such they all add up noise and considerably if not well designed.
and the list goes on from preout to amps to speakers.

just for the sake : amps have generall gain of amplification of 30db or 30 times.

so if you apply with 2 volts of audio signal from preout it would provide 60 volts to speakers.

if those 2 volts had 0.1%,1.0%,10% of noise ( which is common figures general audio components ) they too would be amplified as 0.06,0.6,6 volts respectively with the said 60 volts from amplifier.
and did you know amplifier itself have noise figure of same levels which would be amplified adding to the pre out signals.
that makes the overall noise to double as 0.12,1.2,12 volts respectively,

if we consider the highest noise 12 volts into 4ohms speakers

12/4= 3.0 ampere(voltage/resistance =current)
12x3=36watts( voltage x current=power)

36 watts is definitely audible and loud enough for human ears.

ps: that was all about noise, and distortions are even worse which add up with the sound along with noise. if not carefully considered while selecting components, hope you understood where it leads.

 

[jayadev]

my general prefernce,

i do not go for 4 channel amplifiers.
i prefer two channels and buy two of them if required.
(of course two channels which could be bridged )
4 channel remain bit noisy as too much electronics goes into it. more over heating issues which reduces the life of amps.

i fix speakers in such a positions that sound hits from front ,which could be extremely challenging task in a car but that is the best thing.

monoblock power amplifiers with thick cable is the only way for good subwoofer so no compromises here. but those two channels tied to bridge also does fine but again heating issues and peak power delivery problems arises.

subwoofers : bigger the better,but hey not always costlier the better.

subwoofer enclosure :- hmm its no child play or carpenters job.. a computer is the only way!!!!

linearteam(d0t)dk may help to an extend.[click the isd online on right side coloumn]
thanks to Juha Hartikainen

diysubwoofers(dot)org has covered almost everything theoretically
thanks to brian steele

 

[ilango[speed thirst]]

Crisp truth about audios.

Yeah i can agree on your point to use 2 2 channel amp , but the work required and wiring job etc , can be saved on 4 channel , and yeah so called noise is reduced by reduction of wiring.

We generally use 4 channel to power up speakers in a car ,and no issues.



Though 2 brand amp have same spec , the output differs.
a jbl mono differers from a sony mono

and a RF mono differs from a alpine mono

Amp should be chosen for spl and sql respectively

And enclosure , you have info in the sub woofer , construct accordingly.

But in market some idiots sell sub woofer with port , When a port dimentions are put up in woofer info chart

 

[jayadev]

When a port dimensions are put up in woofer info chart

even the manufacture specs or data does not help much . as that would be inhouse specification not for the car its being used.

as said by ilango, the amplifiers of different manufacturers sounds different and the same happens with bass response , bitter truth is manufacturers over hype the specs.

the 50 watts amplifier may be specified with 150-200 watts.

and there are very unpleasant tricks like adding a steep roll off in amps for low frequency cut off ,which makes amps sound big at vocal ranges but bass response become shallow and weak.

there are lot of specs mfrs dont reveal which shows true face of said amplifier like instantaneous power,long term power,slew rate,type of power supply used etc.

 

[cooldhaya]

I am breaking my head on how to improve the thump effect in my car!

 

[jayadev]

dhaya , put up your configuration here let us see why.

 

[cooldhaya]

Okay here goes.


Front JBL components(entry level) powered by Sony 2 channel amp. Rear Pioneer co-axials powered by HU. Two JBL 1100W subs(again both entry level) powered by JBL mono block amp. Sony USB/Aux-in HU with 3 RCA pre-outs. A very basic enclosure which Ilango gave me because i was very tight on budget , wiring also not branded ones.


I know the enclosure and wiring is the issue here but i don know where to get the perfect enclosures done here. But still i doubt whether i will get good boomy effect heard on the outside. Right now it is audible on the outside but only very little hardly a few feet! With windows rolled down and boot open , the effect will be great! I enquired with many dealers , some said ported boxes will do the trick , some say that is the maximum that can be achieved from my JBL sub , some say it is difficult to get loud effect seen in many Swift's in Verna because of the tightly closed boot!


Am confused! Vocals are really great , but BOOM effect is what is missing!


PS:Don ask the specs or model number , i am weak at remembering those!

 

[jayadev]

dhaya,
just some more facts , dimensions of enclosure , (port size including length)** ,and dia of woofers and JBL mono block amp wattage.
i believe they are not provided by you elsewhere in TAI.
** if no port then better have it asap.!!!your boom boom gets double the power with right kind of port.

for tightly closed boot there is trick :- make a hole or two on the parcel tray with 12'' dia and cover it with flat speaker mesh,grill(rs75-rs150) ..that how it is done normally.

2 jbl woofers can be a killer!!!even one does miracles!!

there is no maximum minimum thing as said by dealer jbl is one of the best in sound technology so..

for your concern let us hope that all components are original as it is difficult to distinguish the counterfeits, which steals vitamin-m only without any juice.

 

[cooldhaya]

Well all i the things which i got is from Ilango our member except for the mono amp and component speakers. I believe him fully so no worries about counterfeits. Enclosure details , Ilango can tell them. 12" dia 1100W JBL sub and 360W mono amp.


One dealer actually said the same thing you have mentioned , a good ported enclosure , branded wiring , cutting a hole in the parcel tray but he demanded 7k for that! I felt it was little too expensive!