Electrical one - 2 subwoofers in parallel...

[jakesmith]

Hello
I have a 4 ohm subwoofer that's rated as 200W RMS continuous
I have an amp that is rated as 500w @ 2ohm or 300w at 4ohm
I was jut about to start install in my car then I thought, couldn't I get another sub the same, wire them in parallel, drive from the amp and therefore create a 2ohm load with 250w per sub?
Is this right?

[E-bmw]

If it were me I would just buy one correct one & flog the one you bought in error.

[jakesmith]

There is only space for 8” subs as it is a low shelf (behind seats in an r8)

The one I bought is fine for the amp, but there is enough space for 2 so seems a shame not to if it would work

[OldGermanHeaps]

yes, that would work.

[jakesmith]

E-bmw said:

If it were me I would just buy one correct one & flog the one you bought in error.

It wasn’t bought in error, it matches the amp but then I realised I could potentially have 2 for even more bass as I drive around!

[E-bmw]

jakesmith said:

E-bmw said:

If it were me I would just buy one correct one & flog the one you bought in error.

It wasn’t bought in error, it matches the amp but then I realised I could potentially have 2 for even more bass as I drive around!

2 subs doesn't mean 2 x the bass.

Each one will do 1/2 the work (approximately) rather than 1 doing it all.

[Peanut Gallery]

As you say wire them in parallel, give you 2 ohm, all will be good!

Just be sure that all the positives are positive, and all the negs are negs, and you have enough power going to the amp.

[GreenV8S]

jakesmith said:

I have a 4 ohm subwoofer

I have an amp that is rated as .... 300w at 4ohm

couldn't I get another sub the same, wire them in parallel, drive from the amp and therefore create a 2ohm load with 250w per sub?

Yes, although you would get 300W total, not 500W, according to the figures you gave.above.

[OldGermanHeaps]

no, 500w, 250w per driver if the coils are identical. At 2 ohms load the amp can deliver more current.

[GreenV8S]

OldGermanHeaps said:

no, 500w, 250w per driver if the coils are identical. At 2 ohms load the amp can deliver more current.

You're right.

[jakesmith]

The reason I’m going for 2 is that the amp is rated at 500w and the subs are rated at 200w. I’ve alrea got the amp from my old car and as there is only space for 8” subs I might as well have 2.
Due to the space of the shelf, it would look odd not to use the full space so given that the subs are only £75 each its a no brainer to install 2 not one now I’ve established the electrics work

Thanks for all the help

[OldGermanHeaps]

2 4 ohm subs in your situation is better than 1 2 ohm sub in a diameter constrained situation, because you are shifting double the amount of air for each watt. You are on the right track.

[ruggedscotty]

wont work - Ill swap you my A6 for your R8 and it will work.... ;-)

[OldGermanHeaps]

you could probably fit 2 or 3 18s in an a6, sounds a good deal to me, but you would be better swapping for my a6 allroad as it has self levelling suspension to account for the weight of speakers amps and extra batteries.
Actually mine has 2x12s, a 1200w pioneer amp ans a jbl ms8 processor already in it so it would save your valuable install time.

Edited by OldGermanHeaps on Sunday 24th March 12:23

[jakesmith]

Thanks for the kind offers chaps, I may take you up on it in a few weeks if the install goes really badly and the car becomes fire damaged!!

Bit of a challenge this one, I’ve worked my way up to it having done some less valuable cars. One of the pains is that to get the amp power cable through the bulkhead from the front battery, involves removing the wiper arms to take out the front trim and front trunk tub to access the battery. It doesn’t get any easier on the inside you can’t just pull the wire through, it involves removing trim pieces and the b&o sub which is behind the glovebox, to do that the glovebox has to come out. So probably half a day or a full day just to get power to the amps.

All downhill after that, apart from stripping the doors with no instructions available online (unlike the Porsche’s I did before that are a lot more common).

Got 8 speakers going in, 2 amps, new head unit with canbus module, passive crossovers and a lpf due to how the 3 way needs to be wired up. Then I’ve got to fabricate the sub box too.

[OldGermanHeaps]

lol fire damaged r8 would sit nice next to my flood damaged repaired pug.