Car Audio - Sound And Music Or More?

[Dillz]

Long overdue and often underrated.

Well done mate

[Dirty32]

Top stuff Smick... Love your commitment to helping others (as usual though lol)!

I for one know next to f*k all about stereo's etc so its good info and sure to be something I use when I decide to raise the money for an overhaul.

I agree with the sticky as it seems that a lot of the same questions come up being asked in a different way and I know it must get to you spending time to reply to all of em Smick!

[sicklaser]

IF YOU NEED TO ASK QUESTIONS ABOUT EVERYTHING WHEN LOOKING AT A NEW CAR STEREO... HOW ABOUT GETTING THE TO SHOP INSTALL IT FOR YOU!!!

ITS NOT JUST AS SIMPLE AS PLUGGING A SET OF SPEAKERS IN THE NEW CD PLAYER YOU GOT FROM SANTA - OTHERWISE SANTA WOULD HAVE GOTTEN OFF HIS FAT ARSE AND DONE IT FOR YOU!

perfectly said

I have run an installation workshop for about 7 years now and there are a few pet hates for installers. one of them being people that buy gear somewhere else and want to pick your brain on how to fit it themselves. usually most of the failed home jobs that I get come thru end up costing more cause you have to spend a few hours back tracking and pulling every possibe piece off the car to find their faults.

im not saying dont do it yourself. but make sure if you are going to try then think about every part of the job and if there are things your not sure on then take it and get it done properly.

a $1000 set of splits wont work as good as a $200 set if not fitted properly. proper installation is equally as important as any component in the system.

[bunna]

lovely work smicky! I've enjoyed reading it, which is a massive credit to yourself as many lesser beings would have drowned us all in boredom and confusion. :wacko: Plenty of good info there for young players.

Speaking of boredom and confusion, here I go

One point - right at the end you mention the use of time alignment to compensate for low frequencies travelling slower than high frequencies. This is incorrect - sound travels at the speed of sound, which is constant within the same medium (air, water, steel, etc), regardless of frequency. Low frequencies are said to be "non-directional" with the respect to high frequencies due to the ability of low frequency sound waves to "bend" around objects (sound barriers on freeways are designed on this principle - think truck noise versus a police siren or traffic). Not the best pic, but

This is the reason why you can have your sub in the boot and it doesn't (or rather shouldn't) sound like it's way back there, as I'm sure just about all of you know, but anyway...

Time alignment is utilised due to the different distance between the listener and each speaker in the system (ie. your driver's side front speaker is a sh*tload closer to you than the passenger side). Since sound travels at a constant speed, but the distance varies, the sounds from the different speakers will arrive at your ears at different times (since speed=distance divided by time - km/h or m/s for instance), so time alignment allows the user to adjust when the speakers produce sounds with respect to each other (the "firing time" if you like), thus enabling the system to sound as though each speaker is equidistant.

Oh and as for resistance/impedance - resistance is the opposition to current flow in DC scenarios, and impedance can be considered its AC cousin (with its nasty "real" and "imaginary" (complex), components).

Edited 02/02/09 08:25 AM by bunna

[TaHa]

Smicky you have done it again mate! Well done!

[smicky]

bunna, you are correct.

I had not meant to mislead anyone if they thought I was actually referring to sound waves within the term itself, being of different speed rather location/distance. ie- rather the relation to distance from source to ear or test device as you have mentioned, in this case (sub in the rear and tweeters in the dash- therefore the tweeter being closer).

Speed of sound is the speed of sound regardless of it coming from a tweeter, or woofer, if they were all exactly the same distance to the test point or listener and air temp was constant, say at around 20deg, again air altitude and humidity also comes into play so say around sea level the roughly speed is around 343 m/s or just over 1200km/h.

(Re-reading that section I can see where people may be mislead, was referring more to concept of a 'perfect system' and what it would consist of... there is a few spots where I have side tracked and mixed it with other info...) - Sorry. 4am will do that too you!

Time alignment is frequently used in high end very expensive home and studio speaker systems. Two of which who are known to have mastered this, are actually Aussie companies... Duntech, and Equinox both Sydney based as well! GO AUSSIE!

btw- thanks for the credit comment bunna... really appreciate it! (again that's for all members!)

Edited 02/02/09 10:02 AM by smicky

[bjc]

Another thing to add is that for every 3dB in volume you have to double the power output.

So if your fully sic subwoofer is doofing out 150dB max with your 1000wrms amp to get to 153dB you need 2000wrms

For every 6dB (close enough to it anyway) we perceive as being twice as loud.

that's why car sound offs use kilowatts and kilowatts of power. You would need 2million 48thousand WRMS using that current configuration to beat the current world record of 181.7dB! or a safe welded on wheels with subwoofers inside it etc, etc!

[bunna]

Yeah that's right- the sound intensity level (measured in decibels dB) is based on a logarithmic scale (or sliding scale as I think smicky mentioned in his bulk post)

[bluey1]

good old year 12 physics coming back to me. looks like the crap they teach at school actually has a purpose after all.

[XR6Turbz]

smicky, well done with that post, bloody hell that is like the stereo bible :-)

nice one man.