JunJTan

I am new to sound system. Do you guys think this will be compatible?

I just bought the Rockford Fosgate P8002 800 Watt 2 Channel Punch Amplifier :
100 W x 4 @ 4 Ohms RMS
200 W x 4 @ 2 Ohms RMS
400 W x 2 @ 4 Ohms Bridged RMS
Total power 800 Watts

I also bought a pair of MTX Subs:

300 Watts RMS to 600 Watts Maximum Each
Frequency response (Hz) 35Hz - 150Hz
Impedance (Ohms) 4
Sensitivity (dB) 88.25
Single 4 Ohm voice coil

JunJTan

no comments from anyone?

yellow350rag

the specs you mention for the amp dont match with the model. If it's a 2 channel amp then there wouldnt be a 100x4 rating or anything x4 for that matter. Also with a 2 channel amp if you're going to bridge it you would need 2 8ohm subs not 4ohm. 2 4ohm subs requires a mono amp for best performance. Also having dealt with Rockford for over 5 years, i can tell you that that amp (meaning an 800 watt Rockford amp, regardless of channels) is almost TOO powerful for a pair of 300watt subs. Just my opinion. Good amp, and good subs, just not neccesarily in that pairing.

JunJTan

thanks, for the best performance, am i supposed to bridge the amp? that will be 800 watts at 4 Ohms on 1 channel, that works as the same way as mono amp, and each MTX sub can maximize to 600 watts RMS.

The specs. above for the amp should be incorrect.

The specs. for amp rockford p8002:

Channels Amplifier Type: Dual Channel
Amplifier Output: 2-channel

Power RMS Power: 200 Watts x 2
Output Details: 200 Watt - 4 Ohm - 2 channel(s),
400 Watt - 2 Ohm - 2 channel(s),
800 Watt - 4 Ohm - 1 channel(s)
Output Power 800 Watt

Features High Pass Frequencieszz: 40 - 400 Hz
Low Pass Frequencies: 40 - 400 Hz
Response Bandwidth: 20 - 20000 Hz
Bass Boost Frequency: 45 Hz
Bass Boost Gain: 0 to +18dB
Crossover Slope: 12 dB/octave

So is the amp compatible for 300 watts RMS subs?

yellow350rag

still no, because when you bridge the amp you need to see a 4ohm final impedance, meaning you would need to wire the 2 subs to 4 ohm... 4ohm and 4 ohm will not make 4 ohm, it would make 2ohm or 8ohm. you need two 8ohm woofers in order to get total performance out of that amp. Yes it will run two 300watt RMS subs, but they need to be 8ohm models, not 4ohm

JunJTan

I understood your point. so how should i do to run the best performance out of them? should I just normally connect the 2 subs into 2 channels for the best quality.

JimRHIT

iTrader: (6)

Run one channel to each sub and you will be more than happy. What kind of box will these subwoofers be going into?

JunJTan

I am using the under strut customized box. It looks awesome. I am still little confused about amp power. If the amp supports 800 watts when it's bridged, so does it only support the total amount of 800 watts from all the subs added together, or it's able to supports more than 800 watts subs as long as each sub is under 800 watts? regardless the ohms under this case.

JimRHIT

iTrader: (6)

The amplifier is capable of delivering a cetain amount of power into a giver "load" (impedance/resistance). When you add subs together .. you either ad up the ohms or you add the inverse of them (series or parallel).

Doing this changes your final load and allows your amp to see something that either easier or more difficult to power. Therefore you can get more or less power from it.

In this situation .. the subwoofers you chose are compatible .. but not the best match for the amp. You will need to run it in stereo (one channel per sub) so that the amp doesn't see a bridged load that is too "easy" to drive .. it will overpower and overheat, essentially.

Don't worry man .. 200W to each of those subs is more than enough .. and you can still say you got 800W... as this still will be the max power output of this amp .. just not the RMS

JunJTan

what you saying is. it will overpwer and overheat when I run it on one channel per sub or when it's bridged essentially?

JimRHIT

iTrader: (6)

When bridged. One per channel is 100% fine.

Bridged is (1/4+1/4)^-1 .. aka 2 ohms ... not good for this amp.

JunJTan

so when bridged, it's fine if i run one sub (4ohms) to this amp. If i run 2 subs (4ohms) into this amp when it's bridged, which they will become 2 ohms, this isn't good the amp. So the best way I need to run 1 sub into each channel, and don't bridge it. Is that what you tried to point out? Sorry, I know I am not smart enough.

JimRHIT

iTrader: (6)

Yep ... and for a better understanding

www.Howstuffworks.com

you don't have to be smart .. you just have to want to learn

JunJTan

thanks.

perrogrande007

iTrader: (4)

Just run 1 speaker to each side. It will sound better in stereo and 400 watts on 2 subs is pleeeenty, especially in a Z. It's not power that you need, it's multiple speakers (which you have) put in the right box (based on specs). People focus too much on power these days. You are going to move more air with more speakers which means more sound. Put 4 subs on 100-200 watts and see how hard that hits vs 1 sub on 1000 watts. The 4 subs will hit much harder and will sound cleaner. The problem with a Z is that you only have so much airspace for subs.

JunJTan

each sub is 300 watts max, but the amp only supports up to 200 watts at each channel. will the amp overheat if it plays long?

JimRHIT

iTrader: (6)

Nope.

The subwoofer's rating means that the manufacturer has power tested them to a certain level. This level gives an impressive marketing number, as well as a degree of confidence to the manufacturer that they won't be getting half of their subwoofers back as returns with fried voice coils.

Trust me .. 200W per 10" sub is plenty and your amp will be fine.

perrogrande007

iTrader: (4)

Agreed, 400watts total is plenty. I remember the days where 400watts was a lot, and people ran more subs instead of more power.

JunJTan

thanks, you guys are helpful. I am gonna install it today or tommorrow, to get me a surprise as you guys said, hopefully.

JunJTan

ok, I installed it today finally. It gives me what I wanted, but the under strut box has too small airspace for the air flows around inside, which limits the performance of the sub. Anyway, it still beats hard though.