3000gt audio question.

[Lordpaxin]

I know this isnt a 3kgt site, but its general info.
after market headunit using stock 6 speaker infinity speakers,

eliminated stock amp.
some say the stock speakers, will blow the amp in the headunit, and i have to replace all the speakers.

 

[SGTalon]

I'm not too educated in stereo (I've done 2 systems) but I've never heard of speakers blowing amps...I don't really see how they could. Maybe I've been living under a rock though.

 

[Fayt]

Your speakers will never blow an amp. If anything, they might be underpowered and not sound as good, but they will NEVER blow the amp. They have no current of their own, how can they blow something?

 

[Lordpaxin]

ok good deal.

i wasnt too sure, but i wanted to ask.

the speakers used to have good bass and sound powerful, they seem lacking now.

perhaps a 10watt RMS drop may cause this?

im gonna replace them all someday anyway.

The headunit has built in crossovers and i had to drop the bass out completley becuause the speakers seemed to be getting raped by the unit, even with less power.

im guessing the stock amp divided power through the channels differntly and now the front and dash speeakers are getting full channel power.

 

[demonchild]

what kinda head unit did you buy that has a 10RMS (which is pretty substancial) drop in power over the stock head unit. That info seems wrong.

In other news, if you are running two speakers off the same channel, there is your problem. Hook only the door speakers up to the head unit, and not the ones up in the dash and you'll get reasonable decent sound. However, that being said, you're goign to want to swap those door speakers if you want "better" than stock sound.

 

[Lordpaxin]

the stock setup was an Infinity 6 speaker setup.
with a underseat amp driving all 6 speakers.
the amp pushed 37 watts RMS

the headunit pushed 25-27 RMS its a sony cdx blah700

on 3si.org it shows the aftermarket installation by tying the door and tweeter speakers together.

4 channels now, rear left and right, and front door and tweeet left and right.

the speakers just act like the sound is blasting them. even at less rms, perhaps the peak is stronger.

but i would assume the sound could be underpowering. with any type of bass one the Hu selected they sound horrible, so i got it filtered out.

just seems odd though, before there was lots of bass, almost woofer sounding, now bass it gone.

a subwoofer not hooked up right someplace?

i have plans to swap out all 6 speaks soon, so that should help it out.

perhaps the ohms of the stock speakers, 4 for the door and rears, and 8 for the tweets is not cool with the power from the headunit. and its just overpowering them.

information gathered from here
http://www.3saudiofaq.com/

speaker specs on stock speaks here
http://www.stealth316.com/2-speakers.htm

 

[Morphius]

Your speakers will never blow an amp. If anything, they might be underpowered and not sound as good, but they will NEVER blow the amp. They have no current of their own, how can they blow something?

Sure you can. If the amp is designed for a 2,4, or 8 ohm load and you run it at a lower resistance, it'll overheat. Thus, blown amp.

Taken from Crutchfield.com (for those looking for a source):
"When you drop from an 8-ohm to a 4-ohm load, you cut the electrical resistance in half, which usually causes your receiver to increase its total power output. Some people are tempted to mate their 8-ohm receivers with 4-ohm speakers, in order to get more wattage. It's wise to avoid this temptation, since it can lead to greater distortion, and cause the receiver to run hot or activate its protection circuitry. "

 

[Morphius]

the stock setup was an Infinity 6 speaker setup.
with a underseat amp driving all 6 speakers.
the amp pushed 37 watts RMS

the headunit pushed 25-27 RMS its a sony cdx blah700

on 3si.org it shows the aftermarket installation by tying the door and tweeter speakers together.

4 channels now, rear left and right, and front door and tweeet left and right.

the speakers just act like the sound is blasting them. even at less rms, perhaps the peak is stronger.

but i would assume the sound could be underpowering. with any type of bass one the Hu selected they sound horrible, so i got it filtered out.

just seems odd though, before there was lots of bass, almost woofer sounding, now bass it gone.

a subwoofer not hooked up right someplace?

i have plans to swap out all 6 speaks soon, so that should help it out.

perhaps the ohms of the stock speakers, 4 for the door and rears, and 8 for the tweets is not cool with the power from the headunit. and its just overpowering them.

information gathered from here
http://www.3saudiofaq.com/

speaker specs on stock speaks here
http://www.stealth316.com/2-speakers.htm

The reason for the difference in how loud it is (front to Rear) is likely the difference in the load you are putting on the headunit. Tying the front and door speaker together could add/delete load on it, depending on how you wired it. By wiring the speakers in series, you are adding resistances. (R1+R2=R3; 4ohm+4ohm=8ohm) Running them in parallel, you cut the resistance. ( (R1xR2)/R1+R2=Requivlent; 4ohmx4ohm/4ohm+4ohm=2ohm)

 

[Lordpaxin]

WOW

this is how its setup.

rear speakers are 4 ohm
and are on the rear left and right channel.

door speakers and dash tweeters are tied together,sharing the signal wires. tweeter is 8 ohm, door is 4 ohm.


like this image shows.
this method is widley discussed on 3si.org,

half of them say the stock speakers will melt down the headunit internal amp.

the difference in sound is not necessarily a difference front to back, its compared to before and after amp bypass.

even by raising volume the speaks cant seem to handle it.
all the noise comes from the front, so the idea that the stock amp crossed over signal is obvious.

the main idea is "will running the setup like this, fry my new headunit before i replace the speakers in 1-2 weeks"

or will it just result in a dead speaker setup.

 

[fostytou]

I ran fine like that for about a week before the stock Infinity dash speakers blew. Then I put them on a low power amp by themselves and the blew in about 3 weeks..... never had a problem with either amp though.

Over the winter I replaced the door speakers and rear speakers with Blaupunkts... my car is pretty loud and they definitley have enough sound quality for the application. Already things sound way better because they cover some of the highs that the dash speakers were supposed to get. I have a set of Type S 3.5 inch speakers for the dash, but I need to pull the dash to install them. Just sitting there they make the car sound 10000x times better, mostly because there isn't that great of a path for sound to travel to your ears from the door speakers, you will get good midrange and bass from them, but the highs can't bounce around as easily and get lost in the cockpit since it is kind of molded around you

And YES, having incorrectly matched resistance CAN blow an amp, what do you think happens when you run 2 DVC (dual voice coil) 4 ohm subs (1 ohm) on an amp not rated for any less than 4 ohms.... either it goes on protect or gets fried. Either way this WURKS your alternator, and requires a larger power wire if you don't want it to heat up/melt.

For anyone who is confused you compile ohmage in parrallel as 1/o + 1/o = 1/To
so in the case of the parrallel DVC subs : 1/4 + 1/4 + 1/4 + 1/4= 4/4 (which reduces to 1 on the bottom)
however if you wire in series you do exactly the opposite. So if you wired each DVC with a positive to one voice coil, a negative to the other coil, and tied their remaining positive and negative together you would get 8 ohms for each sub, and then if the subs were run in parrallel you get a total load of 4 ohms. To do this you multiply the ohmage of each connected circuit, then add the total parrallel load....
EG: (1/(4 * 4) + 1/(4 * 4)) + (1/(4 * 4) + 1/(4 * 4)) = 1/4 for a 4 ohm total load
(in the above equation you can see that you have an 8 ohm load for each sub, then you add them and get a 4 ohm overall load)

If you were wondering there is a 1 farad cap feeding a JBL GTO 601.1 runing an Infinity perfect 12.1D in my trunk. This amp was actually designed to run 2 ohms (59x watts at 2 ohms, 380 something at 4, and safe at 1 ohm with about 900W).... this is a class D amp, and those wattages are RMS. The peak power of the amp isn't huge, but because it is so efficient you use less power to produce more "bang" at a constant rate, and lose a little Uber distored top end. My sub is only rated for 300W RMS, though the peak is 1200W or something.... though this amp can't peak the sub over its limit, it can EASILY make the sub hit maximum excursion at about half power (at max excursion the sub has moved as far as it can, now any power fed to the coil will produce heat instead of motion, which will destroy a speaker). I like the quality of the sub, and with a 1cu foot box its tuned to about 18hz (dropped off real quick after 25hz in my testing with a sin wave generator).... but this makes the loudness (enough) drop and the pound (usually enough) drop and adds a tiny bit of distortion. I have been looking at getting an eclipse or a W7, but I value the little trunk space I have, and a 3.5ft cubic box wouldn't give me any room!

 

[ddavisaf]

heheh Okay, to answer your question.

Yeah, disconnect your dash speakers from your door speakers. It's not worth the risk if you ask me. You might not fry the deck, but you'll damage it. Replace the speakers and match the ohms to the deck, or buy a 6 channel amp. Or a 2 and 4 channel amp or two 3 channel amps. However you wanna do it, but make sure you match ohms. If you'd like more help in selecting an audio systems let us know and we'll give you a hand.

 

[Lordpaxin]

i took the dash tweets out and unhooked the wires, and it does sound a LOT better.

no distortion now, and it sounds more powerful.

when i upgrade speakers can i tie the doors and dash together again? if they are the same ohmage.

 

[demonchild]

NO, you need a crossover network