I Just Got Bored And Typed A Long Answer For A Question...wiring And Ohms

[littleitaly1990]

I think we need like a newb area in the site, where general information can be found quickly and easily, all bundled in one, so I decided to start by making like a short (you could call it that compared to just going to bcae.com or whatever that site is called) explanation of what ohms are and how they relate to car audio. I call it, the idiots guide to Wiring woofers, and if there are any errors, misleading info, hard to understand info, or anything you want to add, please let me know so I could change it up!

Ohms law is a pretty complicated thing (at least in setups with multiple subs and weird ohm loads), but the basics are easy. Ohm's law is V=IR: Voltage = Current x Resistance.

The lower your impedance (ohms) the more heat will be produced. If an amplifier is stable down to say x ohms, then using ohms law you can wire down your subs to that x or higher and be safe. Subs can either be wired directly to an amp, parallel, or series. Each speaker and subwoofer will specify the speakers impedance, usually either SVC (single voice coil) 2 or 4 ohms, or DVC (dual voice coil) 1 2 or 4 ohms in car audio applications. Home audio speakers tend to yield higher impedance levels. When you wire a system one of the most important things to remember is to make sure the impedance level is not below the level that the amplifier is stable down to, as this will very likely cause failure and a destroyed amplifier.

Determining what impedance lever your amp is seeing is easy. The first thing to do is look at the speakers. They will tell you whether the are DVC or SVC. If they are SVC, and you plan on directly wiring the speaker to the amp (pos sub to pos on amp, and neg sub to neg on amp) then whatever ohm your speakers are will be what your amp sees. Therefore, if you have a single voice coil speaker @ 4ohms (which the manufacturer will tell you what impedance it is) wired directly to it's own amplifier (or amplifier channel), the amplifier will see 4 ohms. If you wish to power 2 of these same subs on the same amp (or channel) then you can wire either parallel (pos sub1 to pos sub2 to amp, neg sub1 to neg sub2 to amp) which cuts the impedance in half to 2 ohms at the amplifier; or series ( negative sub1 to neg at amp, positive sub 1 to neg sub2, pos sub2 to pos amp) which will double the impedance at the amplifier to 8 ohms. If you have dual voice coil, treat the wiring of the second voice coil as that of another woofer. So having two dual voiced coil subs can be wired that same as 4 single voiced coil ones, etc. etc. I find this site to be very helpful in determining impedance when my brain is tired http://www.rockfordfosgate.com/rftech/woofer_wizard.asp.

So if you want to wire down to the lowest impedance to maximize the amount of watts your amp will put out, simply wire the subs in the correct way to reach that impedance at the amp.

KEEP IN MIND

Don't go lower than the amplifiers advertised stable impedance level!

The amount of watts RMS your amp is advertised to put out at a certain impedance is the TOTAL it will put out, so if you have say 6 subs wired to that impedance, you will divide what is advertised as the RMS by 6. For example, if your speaker is DVC @ 2 ohms, and you are wiring it to one amp using parallel, the impedance will be 1 ohm at the amp. If the amp puts out 1000 watts at one ohm, the speaker will see a total of 1000 watts. Similarly, if you have 2 SVC speakers @ 2 ohms wired parallel to the amp, the impedance at the amp will be 1 ohm and the speakers will see 500 watts each (1000 total).

As the impedance goes lower, the heat gets higher. Therefore, thicker wire must be used to carry the current and guarantee full performance. This page will show you recommended wire thicknesses.

http://www.stevemeadedesigns.com/board/ind...?showtopic=1005

When you wire correctly, you will have the ability to guarantee that your speakers are seeing the correct wattage, neither over nor underpowered, which will maximize performance as well as improve the life of your speaker...Happy Wiring!

Edited March 20, 2008 by littleitaly1990

[KWP369]

very good info, and i second the new section, we could put the big 3 there, we could have this, and we could move the topic that italy posted bout the different wire sizes and watts that can go through the wire, um we could have a write up on how to work with multiple battery setups, that all i can think of right now, i think we should make a list of common noob question and then find the thread that answers it and move it to the noob section

[littleitaly1990]

LOL I was thinkin we could add like a list of respectable companies and their products, or move that product ratings section from miscellaneous into NEWB haha

...this way, instead of trying to do a search (which is difficult when someone has never used forums and doesn't realize their is a search bar, ie. me way back in the day; or when there is a 4 letter minimum search and they wanna look up btl.) the newbs will know right where to come. And questions about basics in that section will be welcome, because let's face it, we all were bumpin sony's at one time or another, wired like shit, with a walmart head unit, and we needed guidance too!

Edited March 20, 2008 by littleitaly1990

[Tkitt21]

whats an ohm???

hahaha

jk good explanation and info

[littleitaly1990]

whats an ohm???

hahaha

jk good explanation and info

I don't know what it is, but I know how to use it!!! LMFAO

[Tkitt21]

I don't know what it is, but I know how to use it!!! LMFAO

hahahaha

[MickyMcD]

Ohms law is a pretty complicated thing, but the basics are easy.

No, Ohm's law is Easy. Ohm's law wasn't said anywhere in that paragraph.

Ohm's law is V=IR. Voltage = Current x Resistance.

Cheers,

Mick

[bass 4 love]

how do you run subs where the OHM load will be ok with the OHM load on the amplifier stay if i had 6 12'' subwoofers all of them 4OHM a pieace!!!

[littleitaly1990]

how do you run subs where the OHM load will be ok with the OHM load on the amplifier stay if i had 6 12'' subwoofers all of them 4OHM a pieace!!!

Well it depends on the subs voice coil configuration... if you can wire them through a mix of series and parallel to a load that isn't too low for the amp, you will be all set.

And thanks Mick, I knew I missed something!

[bass 4 love]

Well it depends on the subs voice coil configuration... if you can wire them through a mix of series and parallel to a load that isn't too low for the amp, you will be all set.

And thanks Mick, I knew I missed something!

Yeah cause i messed up my amp about 3 days ago!!! and i bought another one and I'm scared to turn it up!! LOL