Compatibility question

[The_Councillor 10+ year member]

So I told my friend I'd help hook up his amp, and subs in his car as I've done it once before so therefor I must be the expert on car audio.

He bought a used amp off of someone and then purchased 2 subs

The amp is a Boss 850 Chaos Monoblock

Max power @ 2 OHM: 850W x 1

RMS power @ 4 OHM: 200W x 1

RMS power @ 2 OHM: 400W x 1

The subs are 2 JBL CS1214 1000 12

250W RMS

4 Ohms, SVC

After doing a bit of research and reading, mostly on crutchfield, I told him I wasn't sure if his amp was going to be able to power his subs, am I correct in this?

If the subs total RMS is 500 watts so the amp would need to put out between 375 and 750 Watts correct?

Which I see the amp is barley capable of at 2 OHM..

Question 2:

RMS power @ 2 OHM: 400W x 1...what does the "x 1" mean exactly in those ratings exactly? is that saying that that is for 1 amp or 1 channel since it a single channel amp?

Question 3:

Lets pretend that his amp will work

His subs are 4 ohms SVC connecting to a single channel amp is this the wiring diagram we would use to make the amp put out the 400W RMS at 2 OHM?

http://images4.crutchfieldonline.com/ca/learningcenter/car/subwoofer_wiring/2SVC_4-ohm_mono.jpg

If you guys need any more information let me know, thanks.

Click to read more...

 

[Jeffdachef 5,000+ posts]

The subs will work fine on that amp. The amp is junk and will probably do more like 40-80 actual watts but it should power the subs for now until he gets a proper amp.

With normal amps that do rated power... 400 @ 2 ohms means 400 watts when it sees a 2 ohm load with the wiring configuration, its a monoblock thats it.

Just wire the subs parallel to the amp like in the diagram

 

[The_Councillor 10+ year member]

Alright thanks.

What about the power wire running to the amp? What gauge would be best for us to run? We've got roughly 18 feet of car to cover.

 

[n2audio 5,000+ posts]

10 awg is adequate for that amp, but knowing an upgrade needs to happen sometime soon you should probably just run 8 awg, it's only a few $ more.

Jeff is exaggerating a bit with the 40-80w comment. That amp will likely do 150-200w at 2 ohms.

A mono amp has only one channel, but it can power multiple subs. It just needs to be connected to an impedance no less than 2 ohms. That can be a single sub, two subs, or as many as you want. The power is distributed among the load so a pair of 4 ohm subs wired parallel for 2 ohms getting ~150w from the amp means each sub sees 75w.

Sub wiring:

http://www.sonicelectronix.com/product/img/subwoofer_wiring/2_subs_SVC_4_ohm_mono.jpg

 

[Jeffdachef 5,000+ posts]

10 awg is adequate for that amp, but knowing an upgrade needs to happen sometime soon you should probably just run 8 awg, it's only a few $ more.
Jeff is exaggerating a bit with the 40-80w comment. That amp will likely do 150-200w at 2 ohms.

http://www.sonicelectronix.com/product/img/subwoofer_wiring/2_subs_SVC_4_ohm_mono.jpg

After impedance rise and voltage drops thats basically what he will see. You'd be surprised how much sound subs can make with only 50 watts clamped going to them.

 

[n2audio 5,000+ posts]

After impedance rise and voltage drops thats basically what he will see. You'd be surprised how much sound subs can make with only 50 watts clamped going to them.

No, i wouldn't.

Might as well throw crest factor in too since the goal here seems to be to go into the weeds for no apparent reason.

The 150-200w approximation is what it would be if it were from a reputable brand.