OHMS are driving me insane!

[Austin 10+ year member]

Here is the problem. I dont know how to figure out what speakers will work with what amp and how much power i'm going to be getting from the amp because I dont know how to figure out what the ohm load of the speakers will be so I know what power rating I should look at on the amp specs(1ohm, 2ohm, 4ohm, etc). So i'm going to elaborate on waht I could be getting.

First..here is the fitting diagram for my car and infinity speakers:

ok, so I want to get the Infinity Kappa Series 60.5cs 6.5" 2-way components in the FRONT :

Specifications

MSRP US$: $349.95 System

Power Handling, RMS: 90 Watts

Power Handling, Peak: 270 watts

Frequency Response (±3dB): 45Hz - 21kHz

Sensitivity: 90dB

Impedance: 4 Ohms

Mounting Depth: 2-3/16"

ok, so I want to get the Infinity 5-1/4" 2-way loudspeaker components in the REAR :

Specifications

MSRP US$: $329.95 System

Power Handling, RMS: 85 Watts

Power Handling, Peak: 255 Watts

Frequency Response (±3dB): 55Hz - 21kHz

Sensitivity: 90dB

Impedance: 4 Ohms

Mounting Depth: 2-1/16"

ok now I have to find a amp for these. I want to go with this amp:

its a PCX-480

SPECIFICATIONS:

Channel: 4.

4 ohm Stereo: 80 x 4.

2 ohm Stereo: 160 x 4.

Bridged 4 ohm: 320 x 2.

Damping Factor: >500.

S/N Ratio: >115 db.

Dimension: 2.375" x 10" x 18.5".

THD: 0.02%.

FEATURES:

Power Input: 4 Gauge.

Freq. Resp.: 4.5 - 100k.

I/P Sens.: 1.5 - 12V.

X/O Slope: 12 db.

X/O Freq.: 30Hz - 4kHz.

X/O Type: 2-way.

Input Type: 12V.

Cooling Fan: Yes.

QBass: Q-Bass

now here is where the problem lies. I have a total of 8 speakers...which I guess would turn into 4 channels because of crossovers(if i understand that correctly)..now how would I figure out what the ohm load for these 8 speakers would be?

Click to read more...

 

[Wonderbread 5,000+ posts]

you would be running 4 ohm stereo!

4 channels total, just wire it directly to your amp!

 

[ShaunMac 10+ year member]

Each x-over with a woofer and tweeter will be a 4 ohm load.

Just think of the woofer and tweeter together as a 4 ohm load.

You'll have one set in each door. 4ohms x 4

With that PPI amp you will be putting out 80w x 4. Plenty of power

for those speakers.

 

[fantomas 10+ year member]

you sure you want components in the back?

 

[evo2k3 10+ year member]

the resistance is calculated for each channel.....since you amp the signal before the x-o's you really only have 4 "speakers" ( i am calling one speaker both right and left) that the amps sees. So each of those is 4 ohms, wire right and left channels up to it, you at 4 ohm stereo like Wonderbread said......and you get 80 watts to each channel. good deal.

 

[Austin 10+ year member]

ok good stuff..now i gotta decide if i want components in the back(i think i do, i have tons of passengers in my car) and also I need to figure out if the tweets will fit in my factor tweet location(on window).

 

[evo2k3 10+ year member]

Originally posted by Austin ok good stuff..now i gotta decide if i want components in the back(i think i do, i have tons of passengers in my car) and also I need to figure out if the tweets will fit in my factor tweet location(on window).

I would suggest comps up front where you have a place for the tweeters, but then many throw a set up coaxials in the the back doors so you dont have to cut for tweeters. Coaxals sound great too.

 

[Austin 10+ year member]

ok, i've decided on Infinity Kappa 52.5I 5-1/4" 2 way Speaker for the rears without components..the only problem is these new speakers are only 55 rms...and the others are 90, so how do I tell the amp to only send 90 up front and 55 to the back? is this possible?

i also heard that I should buy a good crossover...so I was looking at this one

if I did get that, what do i do about the built in crossovers that coem with the speakers? Will they still be filtering out some frequecies even with this crossover? It seems pointless if its going to be using the speaker crossovers anyways..or is this just replacing the crossovers built into the amps?

thanks

 

[ShaunMac 10+ year member]

The PPI PCX-480 has x-overs built in. LP/HP

Use the x-overs on the PPI amp to filter out all

the lows from your speakers. Still use the x-overs that

come with the components. They filter out lows from

the tweeter and highs from the woofer.

Use the GAIN controls on your amp to adjust the amount

of power you send your front speakers and your rear speakers.

External x-overs are good if you don't have x-overs built into your amp.

 

[Austin 10+ year member]

ok thanks

my current setup is 2 12" W3's on a PPI 2200 tahts why I want to get ppi for my other amps so they will match //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

anyways...

does anyone know anyone that will design boxes if I give them pictures and demensions? I can build it but my matt skills are hurtin on trying to figure out the right amount of airspace and tuning a box to the right frequency and all that garb. So if anyone knows anyone that can make some good plans on how to build a box for 4 12" with a amp rack for 3 amps please email me at Austin@Cashville.net

on another note

my electrical system is going to get ***** with 3 amps running off of 80amp alternator..i dont really wanna upgrade my alternator but I dont really have a choice..****

anyone know where I can get a alternator for a 2001 4runner that will fit without much modification? I have talked to one guy that supposedly can hook people up..and ehre is what he said:

"Same case alt as you have now...150 amp $289.00

if you have room for a large case, you can do these amperages...

220 $324

240 $354

260 $394

280 $454

300 $484

350 $549

400 $599

all 1yr warranty except 300 and up..

Let me know if you have any questions.

"

do those lookl ike a good deal?