Celica Forums General Discussion General What the hell is an "ohm" and why should I care?

So I'm about to drop a bigger, badder, beefier system into the back of my car. I just want to have a little background knowledge about this stuff before I go talk to an audio shop. Like what the hell is an ohm? I'll post specs on my new stuff down below.

Sub:
Audiobahn ALUM12Q 12" Subwoofer
1000W RMS Power Handling
120 Oz. Magnet Weight
Efficiency 96.4dB
Frequency Response 18Hz - 500Hz
3" Dual 6 Ohm Voice Coils (3 Subs Wire Down To 1 Ohm Bridged!)
Mounting Depth 5-5/8"
PHAT 1.75" EPDM Rubber Surround
Spun Aluminum Cone
Multi-connect Lug Lock Terminals
Vented Oversized Back Plate
Protective Chrome Finish

Amp:
Audiobahn A8002T 2 Channel 1600W Amp
Class A/B MOSFET Power Amplifier
2 Ohm Stereo Stable
MOSFET High Speed Switching Power Supply
Non-Regulated Power Supply
Double Sided Epoxy Circuit Board
Air Induction Fan Cooled
RCA (Low Level) Inputs
Speaker (Hight Level) Inputs
RCA Outputs
Variable High Pass Crossover : 50Hz - 750Hz
Variable Low Pass Crossover : 50Hz - 120Hz
Variable Subsonic Filter : 20Hz - 50Hz
12dB Crossover Slope
Signal to Noise Ratio >100dB
0.02% T.H.D.
18dB Bass Boost
Bass Boost Control On/Off
Phase Shift 0 - 180
1/2/3 Channel Operation (Mixed Mono)
Tri-way capable
Soft Start Circuitry
4-Way Protection Circuitry: Thermal, Short Circuit, Overload, DC Offset
30A x 2 Fuses
Dimensions: 11-1/16"W x 1-7/8"H x 11-7/8"D
2 x 200W RMS @ 4 Ohm
2 x 400W RMS @ 2 Ohm
1 x 800W RMS @ 4 Ohm

Go here (and other links on this page.)
http://www.crutchfieldadvisor.com/learningcenter/car/subwoofers.html
and read a lot before you talk to the audio shop (if you don't want to get ripped off)

If you want something bigger, badder, beefier...i'd stay away from audiobahn. They are mosly for looks which is chrome. If you want some sound quality and deep bass, go for something else.

So you don't think 2000 watts is going to sound better than the 250 watt single 12" I have now...

Edit: The speaker guy that saw what I was putting in my trunk was like, "...jesus." It was funny.

An ohm is the resistance of the speaker. Speakers have many ohm ratings usually 2 or 4 ohms, but then you have dual voice coil subs which are more flexible in the final ohm reading of the sub. You only have to be sure the amp you buy can run at the ohms of your final speaker load. With those subs(if you have two) you can run each at either 12 or 3 ohms or run both at 6 or 1.33 ohms. So most likely that amp will not be great for those subs, you should look for an amp stable at 1ohm bridged.

If you know anything about audio, Audiobahn doesn't have any subs that can take 2000 watts(besides there huge 30" sub) . I bet you'll never have a 2000 watt rms amp to power a sub like that. Maybe your amp says 2000 watts max...but that doesnt mean nothing. You go buy the RMS, but Audiobahn is way overrated even on the RMS. I use to work at an audio store, and we benchtested an Audibahn amp that said it put out 300 rms/600 max, and we found out it's putting out 160 rms. If you go with reptuble amps such as alpine, JL, zapco, etc. A good amp that puts out more watts then they state is Rockford Fosgate which also comes with birthsheets stating how much watts its really putting out. Just to let you know, our alternators will never ever ever be seeing 2000 REAL WATTS. Audiobahn=blingbling...dont get me wrong, i would get audiobahn if i was going all show.

So would the amps I'm getting HAVE to run at 6 ohms? God I hate electricity.

They dont list amp at 6 ohms (not efficient), you need an amp that puts out around 600 watts at 1 ohms to run both your subs. On second thought that amp you listed should be okay if you run each speaker at 3 ohms and each will see around 300 watts, but you wont be able to bridge it. No matter what those spec say I wouldn't put over 400-500 watts to each speaker.

I was going to run an amp to each sub, that way they'd each be getting 800 watts rms. Why wouldn't you go over 500 watts?

I didn't mean 2000 watts rms to each sub, I ment 2000 watts rms total.

The key words in the amp description is that it is a non regulated power supply, meaning they can draw any ammount of power. From 10 volts to like 16. The more voltage the amps get, the more power they produce. Unless you upgrade your alternator to a high output alternator, change the battery under the hood to a yellow top, AND throw a yellow top in the back too, your system is NEVER going to play to it's potential. I went thru all this for my set up. Don't blow the money on high end electronics, when they aren't going to play to their best. Our alternators are only like 85 amps. The car's electronics with the heater off and the headlights off is about 35-40 amps!! That only leaves about 40 amps to run the system. My system draws about 90 amps, in addition to the regular car stuff! Just be careful, don't want you to waste some large $$$.

^^^yeah, smart guy. What is wrong with your system? I always was impressed with crossfire. If you want a good set up, which has deep, low street bass why still maintaning high sound quality, try two JL W3's, and the JL 500/1 amp. Give them each 1.4 Space sealed enclosure. THat is a great set up. Your never going to get that 2000 watts rms. NEVER. it's really hard to achieve that. You should stick to around 400-500 RMS for you whole system. So you can still have performance and sound. Hope that helps. I'm not trying to be a smartass, just trying to help a fellow celica owner.

Thanks for the help man. Now I'm looking at getting something at around 750 rms instead. I was thinking maybe eclipse or orion? I've got a crossfire 12" with 400 watts ( don't know what it is rms) at the moment. It's not bad, but I want something that you'll be able to feel from other people's cars. Any suggestions?

There are two types of sound. SQ(sound quality) and SPL(sound pressure level). Your going for SPL. IF you want bass that can be felt from other peoples cars (which i dont' like because that's just asking for them to steal it) you should look into the Kickers square solobarics. The hit the ground deep. You know sometimes when your sleeping in the middle of the night and you hear deep bass, well the kickers will do that for you. My friend has two in a small ass box and he parked outside my house, and it knocked off all the things on my walls. It sounds decent. it's More of a Rap and rock sub. It's not meant for techno,trance,softrock. BTW, nice car. I have one question. Since you have those fender flares and all the body is molded in together, don't you ever have to take off the body kit for any reason? Just wondering. Looks like a pain when dealing with fog lights, oilchange, clutch change..things like that. Because i take off my bumper all the time.

The molding is a bitch when the dumbass stereo shop runs it into a curb. Then you have to fix it and repaint the whole car. But other than that, no, haven't had any problems with it. You take the front fender off for oil changes??? I've replaced fog bulbs as well, didn't have to take off the front bumper. And I have an auto, so don't have to worry about the clutch. If I wanted to get a turbo though, I'd be screwed.