spawned_x

I am new to the audio world so please bear with me.

I have been trying to find a simple worded explanation on these wattages but it seems things only get more complicated. I am trying to get the below two things to work together:

Subwoofer: JL 12 W3v2-D4
- Power handling (continuous): 300W
- Dual 4 ohms

Amplifier: Alpine MRP-F240 4-Channel
- 40 watts RMS x 4 at 4 ohms
- 50 watts RMS x 4 at 2 ohms
- 100 watts RMS x 2 bridged output at 4 ohms

Would there be a problem using a 200W amp with a 300W sub in terms of over-heating, under-power, etc? I mean, I would assume having a 300W amp to go with a 300W sub would be ideal but that's not the case just yet.

Any help would be much appreciated. Also, if there is a need to get another (more powerful) amp, what numbers should I be looking out for and possibly any suggestions as far as Alpine models go?

Thanks!

Eli47

There's no problem in using a 200W amp on a speaker that CAN handle up to 300W .
However, the(Alpine) amp will only put out 100 watts to EACH coil, barely enough to move a 12" sub properly, without overdriving the amplifier to get volume levels that you may LIKE.
So.., yes, more power will prevent chances of overdriving your amp into distortion, which will damage the woofer.
I would recommend no less than 150W to each voice coil if you can do it.
keep the 4 Ch for the other speakers, and get a dedicated amplifier to run the subwoofer.

spawned_x

I do appreciate your quick reply and understand the basic concept as it seems straight forward but it always helps to get clarification from someone who knows so thanks.

To make the decision easier for myself, here are few things:

1. I only plan to connect the sub to the amp (no speakers) so having multi-channel vs mono amp would not make a difference. I just happen to get my hands on the MRP-F240 which unfortunately is under powered for the sub.

2. What 'best choice/dedicated' amp will give me 150W to each coil (300W to dual coils is I am assming what you meant since the sub is 300W D4)? I have come across the Alpine MRP-F200 Multi-Channel and MRD-M300 Mono Channel.

I just happen to go with Alpine since it's all I know of and JL amps are out of my budget but if you have any suggestions, please share!

Haunz

iTrader: (3)

there will be no problem.....

if you go to a larger amp that sub will handle up to about 5-600 watts depending on the enclosure and your listening tastes....

spawned_x

Thanks -- not sure if you read my reply to the post that was made earlier since we both posted around the same time but as for enclosure goes, it's exactly like this one: http://www.bybb.com/images/products/se12.jpg

Also, about wiring kits, which one to use? I have seen them range from 0 guage to 16 guages (I think) and would spending more money on a kit ideally mean better results or the extra money is just to get the name brand?

Eli47

Ok, so you plan on using the Alpine in 2 ch. to two voice coils on the same woofer.
Shouldn't be a problem as long as the amplifier is operating in dual-Mono.

As for the best choice in Amplifiers, I'm hesitant to recommend a particular brand, however I will offer some insight which may help in making a wise choice.
There are 2 designs in amplifier operation, Voltage driven, with current applied last, and Current driven with Voltage applied last.
Voltage driven Amps (like the Alpine) typically sound more musically accurate, but are a tad short on attack (hitting hard), and although bass response seems more extended than Current driven types, and their treble more earpleasing especially at moderate to high levels, it's recommended to get a higher power (voltage driven)amplifier to drive sub-bass.
Current driven designs tend to have a very fast attack/response, seemingly tend to fall shy on the very low frequencies, and somewhat harsher on the upper range at higher levels.

As for power cable, I'd say for the amount of power you plan, an 8 AWG cable will do nicely considering 16feet of + cable to be used. (please remember to beef up the ground connection from the battery negative, to the chassis of the car, same gauge of ground used for the amplifiers or better.)
Some kits are indeed more expensive, some of that is attributed to brand name, but mostly because the actual cable uses better copper, and more strands in the same gauge, so physical comparison is recommended, look for the most strands in the cable,a pliable cable is also more expensive, but easier to deal with when installing. Look for as much shielding on the RCA Interconnecting cables, good quality connectors also make a small difference, not so much with sound, but rather durability, and aesthetics.

spawned_x

Thanks for the detailed reply! It's a lot more information than I anticipated but helps that much more. Since you mentioned Alpine amps are voltage-drive and "it's recommended to get a higher power (voltage driven)amplifier to drive sub-bass." Would that generally mean to always get a higher (max watt) power amp then the sub itself (if not then atleast of equal power)? Because with the current step, it seems that the amp is 100 watts less than the sub unless I misunderstood the comment.

Eli47

Yes, that's what I would suggest, to get as much power as you can, the more the better, and the less chance of damaging your subs(within reason).
The extra power will allow for great headroom on dynamic passages, without straining (distorting) the amp.

keep in mind that power is rated per channel, not total, which can be misleading.
Each coil(speaker) get X- amount of power, the total of all channels/power is irrelevent..,except for bragging rights.

Cluster

If your willing to put in a bit of reading time, Basic Car Audio Electronics is a great site which goes step-by-step through the theory of electricity, and progresses into explaining how amps and speakers work.

http://www.bcae1.com/

For your setup, if you can, always go for a bigger amp. Matching watt for watt amp-speaker works, and if your budget is tight may be your only option, but in general i like to have my amps have ~20% more RMS wattage than the speakers they'll be hooked up to.

Another thing, and they do a decent job explaining on BCAE, is speaker resistance. If you use the two channel amp with the DVC(Dual Voice Coil) sub, don't worry about it, just enjoy it. But if you were to have a single channel amp with a DVC sub, then you should know the basics of series/parallel speaker hookups.

Check out the site, lots of good tips for ya.

Good Luck

spawned_x

Thank you so much to both of the repliers, all your help is much appreciated. Precis and clear! It appears, the current amp will have to do, for the moment atleast, until my budget allows me to get a more powerful one.

Thanks again!