Car Audio?

[Vyk]

This really isn't the forum or message board for this. But I figure everyone here probably has other hobbies outside of video games and the internet and stuff. So why not. I love this place and trust everyone here. So if anyone tinkers with the sound systems in their cars. I have a question. Possibly more to come

I'm changing the head unit for my car. For those that are like I used to be and have no clue what I'm talking about, I'll translate. I'm replacing my car's radio.

My car has six speaker surround sound. Tweeters in the dash. Midranges in the car doors (its a 2-door coupe). And a sorry excuse for subwoofers in the trunk (these are currently 6x9 generic paper brand). My tweets and mids are dying. I've had to unplug one of each because of scratchy noises. And now my second mid is making the same noise. Everything's going to need replaced eventually. But we'll stick with the here and now

I got a new radio online which should be here next week. I've read the manual online. It stresses very severely that its made for four speakers only. Which are part of the regular wiring in the back. Eight speaker wires (positive and negatives for each speaker) and power and dimmer and stuff that radios do. All go into one plug. Adjacent to this however is 2 RCA outputs (think audio/video cables for those that don't know). And next to those are 2 pre-amp outputs (essentially the same thing in looks though I have no idea what the real difference is). So I can run six speakers, just that the last two need an amp which plugs into these. I'm assuming anyway. Regardless, I know the best audio you can get involves amps. So I'm going that route regardless.

One quick question. This pre-amp thing. Does that mean I can plug subs into these without having to have an amplifier to power them?

Despite the answer to that question, I'm looking at two decent amps. I'm not one of those people that likes to feel my chest vibrate and break windows while driving down the raod. I don't need that kinda bass. So I'm not looking at getting a 4000 watt amp

I've found a decently priced 2400 watt 2 channel (1200 watts per speaker for stereo). I would NEVER max that out. I like my hearing. So with that in mind. I figure I don't need anything that powerful. SO! There's also this nice 600 watt one.

So here's my main question. In case I want to upgrade later. I'm sure people are aware of the possibility of blowing a speaker from overload. My buddy recently told me that there's a little known fact about blowing speakers. Sometimes they like to keep drawing power. And if you don't have a unit to provide that power, they burn out. So he suggests buying an amp with more power than the speakers. Because if it gives too much power, it'll just turn off. Supposedly if you have speakers that can handle more wattage than the amp can provide, they'll burn out trying to draw on power that isn't there.

This seems kinda counter productive. I would think you'd want speakers that could handle more power than the amp can provide, so it'll never juice them too much. But maybe there is a failsafe

So... what should I buy for? An amp with more watts, or speakers with more watts?

This way I'll know, if I buy the 2400 watt amp, I can still be safe buying a couple 300 watt subwoofers without worrying about blowing them. Or if I buy the 2400 watt amp should I get something along the lines of 1100 watt subwoofers to make them more close so I don't blow them (in which case I'd get the smaller amp and lower watt speakers)

Any knowlege on the issue would be appreciated. Sorry about the long post

[Samuraid]

This really isn't the forum or message board for this. But I figure everyone here probably has other hobbies outside of video games and the internet and stuff. So why not. I love this place and trust everyone here. So if anyone tinkers with the sound systems in their cars. I have a question. Possibly more to come

I'm changing the head unit for my car. For those that are like I used to be and have no clue what I'm talking about, I'll translate. I'm replacing my car's radio.

My car has six speaker surround sound. Tweeters in the dash. Midranges in the car doors (its a 2-door coupe). And a sorry excuse for subwoofers in the trunk (these are currently 6x9 generic paper brand). My tweets and mids are dying. I've had to unplug one of each because of scratchy noises. And now my second mid is making the same noise. Everything's going to need replaced eventually. But we'll stick with the here and now

I got a new radio online which should be here next week. I've read the manual online. It stresses very severely that its made for four speakers only. Which are part of the regular wiring in the back. Eight speaker wires (positive and negatives for each speaker) and power and dimmer and stuff that radios do. All go into one plug. Adjacent to this however is 2 RCA outputs (think audio/video cables for those that don't know). And next to those are 2 pre-amp outputs (essentially the same thing in looks though I have no idea what the real difference is). So I can run six speakers, just that the last two need an amp which plugs into these. I'm assuming anyway. Regardless, I know the best audio you can get involves amps. So I'm going that route regardless.

One quick question. This pre-amp thing. Does that mean I can plug subs into these without having to have an amplifier to power them?

No. Pre-amp outputs are unamplified by the head unit's internal amps. You must connect an external amp to these outputs if you wish to also connect speakers.
You may also be able to power all the main speakers from the head unit. If you are using stock speakers, they car manufacturer probably has the speakers bridged in such a way as to be driven off 4 channels at 4Ω each, which is a very normal load for a head unit. As long as you drive your subs with a dedicated amp (and use a highpass/crossover to keep the bass frequencies from running through your head unit's amps) you will probably be fine.
If you plan to upgrade your speakers though...better to drive them off a dedicated amp.


Despite the answer to that question, I'm looking at two decent amps. I'm not one of those people that likes to feel my chest vibrate and break windows while driving down the raod. I don't need that kinda bass. So I'm not looking at getting a 4000 watt amp

I've found a decently priced 2400 watt 2 channel (1200 watts per speaker for stereo). I would NEVER max that out. I like my hearing. So with that in mind. I figure I don't need anything that powerful. SO! There's also this nice 600 watt one.

So here's my main question. In case I want to upgrade later. I'm sure people are aware of the possibility of blowing a speaker from overload. My buddy recently told me that there's a little known fact about blowing speakers. Sometimes they like to keep drawing power. And if you don't have a unit to provide that power, they burn out. So he suggests buying an amp with more power than the speakers. Because if it gives too much power, it'll just turn off. Supposedly if you have speakers that can handle more wattage than the amp can provide, they'll burn out trying to draw on power that isn't there.
Well, this is partially true and partially false. If you have an amp that supplies significantly less power than is recommended for your speakers, the amp will clip at higher volumes which will slowly damage your system. On the other hand, if your amp is more powerful than is recommended for the speakers, and you pump too much current through the speakers as a result, it can fry the magnetic voice coils in the speakers and completely damage them. This can also cause an over current and possibly cause amp damage (depending on the circumstances). You should either find an amp that is close in power to what your speakers require, or else be careful about the volume. Also, make sure you match the correct power rating with the correct speaker impedance, as most car speakers are 4Ω, but some subs can be 2Ω depending on the specs and whether they are bridged or not.


This seems kinda counter productive. I would think you'd want speakers that could handle more power than the amp can provide, so it'll never juice them too much. But maybe there is a failsafe
Again, if the amp can't provide the power and the volume is too high, the amp's output will clip (the amplification transistors will be saturated) which is bad.


So... what should I buy for? An amp with more watts, or speakers with more watts?
Match things somewhat evenly if possible. :) But going for a more powerful amp is generally the best compromise.


This way I'll know, if I buy the 2400 watt amp, I can still be safe buying a couple 300 watt subwoofers without worrying about blowing them. Or if I buy the 2400 watt amp should I get something along the lines of 1100 watt subwoofers to make them more close so I don't blow them (in which case I'd get the smaller amp and lower watt speakers)
Something else you will want to consider:
If you are getting a 1200W (peak) amp and you have the volume up, you will be dimming your tail lights each time the bass hits. You should also consider getting a capacitor to alleviate the load on your car's alternator. (a ½ to 1 Farad capacitor should be good enough)

Lastly, it's more worthwhile to buy a name-brand amp that is lower wattage than the cheapest thing you can find with high wattage. A well-built amp will do the job far better than something cheaply built with huge numbers. (I'm not saying this is what you are doing, just be careful what you buy).
For amps, Alpine, Rockford Fosgate, Infinity, Pioneer Premier, and JBL have good offerings.

This post was a little rushed typing, so forgive any oversight or unanswered questions.

By the way, what head unit did you get?

[Vyk]

I admit I'm pretty aware of the lack of respect Roadmaster has in the car audio feild. So don't look at this like I'm trying to get a really decent system and failing miserably. This is the geeky side of me coming out.

http://www.roadmasterusa.com/stereos_car_vr3.php

Roadmaster apparently has a few subsidiary companies. One of which is VR that makes these nice units. The 500 is the one I'm getting (but for less money. I found it wholesale for $80). And as I said, since I don't want competition quality sound or anything, I don't have to spend a lot. But the selling point on this was the options. These two are the ONLY units I've found to have SD card slots. I have kind of a thing for SD since its fairly universal. I have quite a few so that's really handy. More handy than anything I think. Makes it easier than using an MP3 player and the USB or Auxiliary ports (both of which it has). My thing is, with the USB port and an SD slot, and able to read MP3 discs. And Auxiliary input... my MP3 listening options are endless. And I love that for some reason. (USB extrenal hard drive full of MP3s anyone?)

Its really really hard to find decent priced units that have USB ports (and aren't ugly as hell in my opinion). Auxiliary inputs are a lot more rare than they should be too in my opinion. I HAD to have an MP3 compatible unit. And it HAD to have an Aux input. But yeah, this is the MOST user-friendly unit I've found. So cheap or not. It has a year warranty. I don't plan on abusing it. Its perfect for me in my opinion. But if you can find anything I should be wary of, critique is appreciated

On the subject though. I suppose it'd be prudent to point out the amps I'm looking at so you might be able to decide if being cheap also risks them for being junk as well. The watts wasn't the only selling point

Here's the 2400 watt one (http://cgi.ebay.com/NEW-2400-WATT-LEGACY-LA2098-2Ch-Car-Audio-Amp-Amplifier_W0QQitemZ220043840298QQihZ012QQcategoryZ48599QQrdZ1QQcmdZViewItem)

600 watt that I'm more likely to get since its cheaper and I don't want a lot of thumping power (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220034359908&ssPageName=MERC_VI_ReBay_Pr4_PcY_BIN_Stores_IT&refitem=220043840298&itemcount=4&refwidgetloc=active_view_item&usedrule1=CategoryProximity&refwidgettype=cross_promot_widget)


Product Description:
Legacy Car Audio LA2098 "ICE" 2-Channel 2400 Watts Max Car Audio Amplifier

Details:
·1200 Watts x 2 Output ·2400 Watts x 1 Bridged Output ·Variable Hi/Lo Electronic Crossover Network ·Variable Bass Boost ·Variable Input Level (Gain) Control ·Power ON LED Indicator ·LED Protection Indicator ·Hi/Lo Impedance Input ·I·lluminated Top Panel ·Thermal/Overload/Short Circuit Protection ·Anti-Thump Turn-On ·Dimensions (H x W x L): 2.2" x 12" x 19"

I've been reading up. I know its best to look for bridgeable amps. For better performance you'd want crossover and low/pass filtration and such. It has a built in crossover. Its got failsafes for overload and heat protection. The impedance input. Anti-thump. I mean it might not be performance quality itself, but again, I just want something that does what I need. And this has a lot more to it than I was actually looking for. But again, any critiques would be welcome.

Either way I refuse to spend a grand on my sound system. A couple hundred should be enough to suit my needs. Especially with cheap stuff like this. And I know if you set everything up right, a cheap system can do you good for a long time. And since I'm not even expecting much it'll probably go beyond what I need. Which is a plus. Yay for being a novice.

Edit: Also, thanks for pointing out the ohms thing, I wasn't thinking about that

[Samuraid]

Well, the system you described certainly provides what you will need, but as you suspected, there are some things to be aware of.

If you want my honest opinion about the Roadmaster: stay away from it. It may have a lot of useful features, but the quality is very subpar.
The biggest shortcomings are the signal to noise ratio, the warranty, and the preamp voltage level. The SNR is only 80dB, which is very low for a car unit and involves a very audible level of noise in the system. You should get a unit with at least a 90dB SNR, and higher is better.
Also, from reading the user manual, the warranty is only 30 days. This instantly raises the red flag as to the quality of the unit. A good unit is generally warrantied for a year or more.
Finally, the pre-amp voltage level is only 1V. This translates to a poorer signal to your subwoofer amp. A good head unit should provide pre-amp outputs at 2V, minimum.
There are many units for less than 100$ that give you SNRs > 90 dB and many other things as well.
I would strongly recommend getting a unit such as this one:
http://www.cardomain.com/item/PANCQC1333U
for example, because it is a name brand, comes with a full year warranty, has a 96dB SNR, 2 x 2.5V preamp outs, MP3 playback, and a front AUX input. (also free shipping from that site, and a free wiring harness and install materials)
The choice is ultimately up to you though. Just make sure to be absolutely sure of things before spending money. It may seem like a larger sum now, but it will be a good choice down the road as you won't have to spend more money replacing cheaper parts that may have failed.

As for the amp on ebay, the price alone makes me very wary...however, for $30-something + $24 s/h, it's not a huge loss if things don't turn out ok. By the way, the 300W rating is peak power, which is an easily-falsified and very inaccurate rating of power. Many manufacturers bloat this number even though the amp may not actually be all that powerful. RMS (@ 1kHz) is a moderately better rating, and full band RMS is by far the most accurate power rating.

EDIT:
May I recommend getting a Pioneer amp instead of the Legacy amp:

300W 2 channel Pioneer (http://cgi.ebay.com/Pioneer-GM-3200T-300-Watt-2-Channel-Power-Amp-GM3200T_W0QQitemZ220040693940QQihZ012QQcategoryZ39736QQssPageNameZWDVWQQrdZ1QQcmdZViewItem)

The pioneer amplifier ratings are CEA2006 compliant.