best audio setup w/o subs?

[fluidmotion]

also, what's the best way to test if an amp is functional, and how do people even burn out amps?

I mean, I'm an EE student, and I could build an amp, and I guess you could just take an input voltage and measure the output voltage, and see what their outputting, but is there an easier method?

And I can understand accidentally overloading a speaker, but not so much an amp. Wouldn't you have to do something pretty stupid to overload an amp? Pretty much wondering, what the most common mistakes are for wrecking an amp.
Modified by fluidmotion at 1:57 PM 7/14/2005

[PoorManQ45]

TO burn up an amp you put an ohm load on it that is lower then it is capable then handling.

Meaning if it's rated at 4ohms stable and you put a 1ohm speaker on it one of two things will happen: 1. The amplifier will go into protection more, or 2. The amplifier will not go into protection mode and it will play just fine for awhile as it gradually heats up and eventually melts of hopefully shuts itself down.

Note that most current amps have either thermal overload or low ohm protection.

Basically it's almost impossible to kill an amp without doing somethign extremely stupid.

Example of something stupid: Connecting the speaker outputs of an unbridgable amp. Or somehow connecting the speaker out put to the RCA in/out.

Oh yeah, what happens alot of times is the RCA inputs on a receiver will fail. This basically renders it useless.

[Timeless240]

FOR BENCH TESTING A CAR AMP:

Is it possible to use the 12 volt lead off a computer power supply? How comparable electrically is it to a car battery? Of course, to test an amp, you would also need a 12v signal to the remote turn on line of the amp.

Just throwing out ideas, I vaguely remember seeing a pic of someone who scrounged together a very rough home theater system with an old computer power supply, a dvd player's stereo red and white audio outputs, an old budget car amp (connected to the plastic molex power cable or the PSU) and bookshelf speakers. Sure it was ugly, but the person claimed it worked well. (and was a lot cheaper than a dedicated home theater receiver/amp)

[PoorManQ45]

Yep, that's what alot of people do when using 12v equipment in a home.

Computer power supplies are much cheaper then dedicated 12v converters. You can get a 30amp @ 12v computer power supply for ~$20 where as a 30amp dedicated converter would cost close to $100

[fluidmotion]

hey Q, how do I setup the system with the 2 amps? regularly, you would connect one amp's input to the head unit and the outputs to the two crossover boxes, but that wouldn't work if you want to have the tweeters on one amp and the speakers on a second amp...

[PoorManQ45]

You should use a single four channel amplifier with seperate gains for the front and back channel.

Then you connect the RCAs from the HU to the amp. You should use two "Y" splitters to get the four inputs you need. Also, on the channels that you're using for the tweeters you'll probably have to put an external crossover in between the RCA and amp.

[fluidmotion]

sorry, I'm still confused. The output of the amp is still going to connected to the infiniti crossover, which outputs speaker and tweeter.. so in turn, isn't it always going to be only 1 amp per tweeter and speaker?

unless, you can put the infiniti crossovers before the amp, so it is directly connected to the HU and the outputs from the crossover tweeters go to an amp and the output for the speakers go directly to an amp.... would doing it that way have any repercussions?

maybe that's what you said... but I'm not sure..

[fluidmotion]

So, I've got everything installed. Except I chose to skip the infiniti crossover boxes. Unfortunately, the system doesn't sound as well as I thought and I'm pretty sure it isn't any of the components, but more of my install.

it could be...

1. Speakers need time to be broken in2. need some more insulation on the doors and around the speakers3. I skipped infiniti's crossovers and used the ppi crossovers instead. (i read that this is bad)4. my head unit sucks. (pioneer DEH xxx, one of the supertuner models, came w/ the car 45wx4).

The wiring should all be good. Instead of using the crossovers that Infiniti provided, I ended up using a ppi 2240 (75wx2 @ 4 ohms) for the tweeters and a ppi 2360 (150wx2 @ 4 ohms).

Both amps were tested using my dvd player and a car battery with the kappa perfects components and they work...

Anyway, the tweeters are clean and clear, as expected, but the woofers are crackly. I have pioneer 6.5 speakers in the back and they get louder than the kappa perfect woofers. And I can't seem to turn the woofers very high on the amp...

also, for some reason, the woofers are considered back speakers to my hu. Are all speakers on the RCA output considered back speakers?

[fluidmotion]

I got it working, just futzing with it. The HU distorts on certain settings, and it sounds much better now. Thanks.

[PoorManQ45]

happy to hear that you got everything working properly.

What was the problem with the mid-bass drivers?

[fluidmotion]

nothing was wrong with them, just when certain settings on the HU are on, it seems to distort the signal to the speakers.

I just might need to get a new HU, but it should be fine for now.

Are newer hu's with the 5 v RCA Pre-outs much better? or does that not make a difference. That should make it easier for the amplifiers to do their job and increase the output I'm guessing, but I guess it still depends on how good the HU is.

Also, I decided to keep the stock S14 speaker grills, would that cause a problem? I know the Infinity Kappa's speaker grills protrude more, and I think that the speakers are just barely touching the grills if I turn the volume higher. Just didn't want to change the grills cause they don't fit in the original spot without some more cutting up of the door panel.

[PoorManQ45]

Are newer hu's with the 5 v RCA Pre-outs much better? or does that not make a difference. That should make it easier for the amplifiers to do their job and increase the output I'm guessing, but I guess it still depends on how good the HU is.

It's not just the pre-out voltage that matters. The voltage is just the signal carrier. If you feed a crappy signal out of a high voltage preout it's still going to sound like crap. If you feed a good quality signal over a low voltage preout it's going to sound good.

Also, it won't really make a difference with the amplifier. You'll just have to set the gain(s) diffferently.

Also, I decided to keep the stock S14 speaker grills, would that cause a problem? I know the Infinity Kappa's speaker grills protrude more, and I think that the speakers are just barely touching the grills if I turn the volume higher. Just didn't want to change the grills cause they don't fit in the original spot without some more cutting up of the door panel.

What do you mean it touchs the grill at high volumes? If you mean the surround hits the grill then that's a problem and can cause damage to the speaker's suspension and motor coil.

[szh]

youre lucky i cant find my camera. the wire on my dad's audio system in our basement is 18 awg, and so is the car audio wire im holding in my hand. its obvious that the home audio wire has more strands than the other wire.

Well, the number of strands simply depends on the manufacturer of the wire and what wire it is, etc. Some "18 awg" may have more strands, some may have less - in fact, you can get "single-strand" solid 18 awg wire too!

The point is that the number of strands has less of an effect (in general) than the total cross-section area - the "18 awg" is a measure of the cross-section area.

Z