How many watts do I need for a sub?

[ajd344]

Currently I have a Pioneer DEH-2100IB headunit with factory JBL speakers. With the correct EQ settings and a lot of volume I can actually get decent bass out of them. However I feel I'm pushing my speakers to the limit and would like to improve my bass using a subwoofer.

I want to get a set up that performs well: I'd like to be able to "feel" the music, but on the other hand I'm not wanting something thats gonna shake my car apart, strain my electrical system or be heard a block away. I just want good bass inside the car.

I feel because I'm able to get something half decent out of pushing a 50W peak head unit hard, it shouldn't take a lot more power to achieve what I want. Right?

I'd like to spend as little money as possible (without sacrificing too much quality), so what kind of set up would I need? How many RMS watts? Would a 200W rms sub and amp be alright?

[Exit9]

How many watts you need kind of depends on the subwoofer speaker you pick out - high or low sensitivity and impedance (4 or 2 ohms) for example - and what sound pressure level (SPL) you want to achieve inside the car. Amps generally put out more power into a 2 ohm load and high sensitivity speaker (i.e. speakers range from about 86 dB to 93 dB). Every 3dB increase from baseline 1 Watt output at the sensitivity rating requires a doubling of amplifier power.

The Eclipse XA1200 is rated at 500W RMS @ 4 ohms (or 350W RMS @ 4 ohms depending on which source you use). This is probably enought power to run most single subwoofers for non-competition use and it is on closeout for $129. The Eclipse brand is being discontinued in the US and Eclipse equipment is selling at a pretty good discount (i.e. Amazon, Woofersetc.,others). It is fused for an 80 amp load, but I don't think it would be driven anywhere near that hard, or you could need a big three upgrade and possibly a new high output alternator. It is nice to have a high amp power capacity for short peak dynamics, but not have it operate full capacity and put a big load on the electrical system. (You don't want a dead battery.)

The Eclipse XA1200 is a class D ICE design (small and high efficiency) and it will fit on the driver's side rear seatback. That leaves the passenger side rear seatback for adding a 4-channel amp and small processor if you want to expand later.

Everybody has their own favorites for amps and subs, so I am sure you will get many other recommendations. I was trying to pick something low cost.

I really am not familiar with best deals for a good quality subwoofer. I went to a good local custom audio shop. I told them I was looking for a sub to play the low bass in recordings, but that I wasn't looking for anything more than reasonably loud bass to achieve balanced music output. They recommended a lower-line ($100) JL Audio 12" speaker in a JL Audio enclosure ($50) in the trunk, so I went with that. JL Audio is probably not your best deal, but they make quality products and I think most people who get them are happpy with their decision.

You also will need a wire set for the amp. I went with Stinger brand 4 gauge power wire with the included 150 amp fuse which supports the Eclipse and provides expansion capability for a 4-channel amp. All wires are not the same and consequently you will see other 4 gauge wires that are not made as well (i.e. less copper) so they include a lower rated fuse. You need the power wire to have a properly sized fuse that is at leash higher than the fuses on your amp and ideally with room for growth into a 4-channel amp.

[gameguru1360]

Originally Posted by Exit9

How many watts you need kind of depends on the subwoofer speaker you pick out - high or low sensitivity and impedance (4 or 2 ohms) for example - and what sound pressure level (SPL) you want to achieve inside the car. Amps generally put out more power into a 2 ohm load and high sensitivity speaker (i.e. speakers range from about 86 dB to 93 dB). Every 3dB increase from baseline 1 Watt output at the sensitivity rating requires a doubling of amplifier power.

The Eclipse XA1200 is rated at 500W RMS @ 4 ohms (or 350W RMS @ 4 ohms depending on which source you use). This is probably enought power to run most single subwoofers for non-competition use and it is on closeout for $129. The Eclipse brand is being discontinued in the US and Eclipse equipment is selling at a pretty good discount (i.e. Amazon, Woofersetc.,others). It is fused for an 80 amp load, but I don't think it would be driven anywhere near that hard, or you could need a big three upgrade and possibly a new high output alternator. It is nice to have a high amp power capacity for short peak dynamics, but not have it operate full capacity and put a big load on the electrical system. (You don't want a dead battery.)

The Eclipse XA1200 is a class D ICE design (small and high efficiency) and it will fit on the driver's side rear seatback. That leaves the passenger side rear seatback for adding a 4-channel amp and small processor if you want to expand later.

Everybody has their own favorites for amps and subs, so I am sure you will get many other recommendations. I was trying to pick something low cost.

I really am not familiar with best deals for a good quality subwoofer. I went to a good local custom audio shop. I told them I was looking for a sub to play the low bass in recordings, but that I wasn't looking for anything more than reasonably loud bass to achieve balanced music output. They recommended a lower-line ($100) JL Audio 12" speaker in a JL Audio enclosure ($50) in the trunk, so I went with that. JL Audio is probably not your best deal, but they make quality products and I think most people who get them are happpy with their decision.

You also will need a wire set for the amp. I went with Stinger brand 4 gauge power wire with the included 150 amp fuse which supports the Eclipse and provides expansion capability for a 4-channel amp. All wires are not the same and consequently you will see other 4 gauge wires that are not made as well (i.e. less copper) so they include a lower rated fuse. You need the power wire to have a properly sized fuse that is at leash higher than the fuses on your amp and ideally with room for growth into a 4-channel amp.

typically you want an amp that has at or slightly above what's rated for the sub. So like in my setup, I have a hifonics olympus 12" sub that supports 1600 rms watts and an MB quart 1500.1 amp that actually puts out about 1650 rms watts, give or take. Also what kind of music determines what kind of box you'll be putting your sub in.

Sealed boxes work best for rock & pop whereas vented/ported boxes work best with hiphop, rap, R&B but sometimes rock as well. The inside volume also determines how loud or deep your bass can get. My 12" box has 3 cubic feet which is a lot. Most standard vented boxes have 1.75" cubic feet. If you're looking for quality, go with a sealed box. They can be small but still sound good whereas ported/vented require more volume. For SPL or loudness, go with a ported/vented.

Also sealed boxes require lots of power from an amp whereas vented/ported don't require as much. This means you can underpower a sub and it'll still sound loud. So if you have a single 12" sub that supports 800 rms watts and have an amp that puts out 600 rms watts, it'll still sound loud in that vented box if you tune it right. With a sealed box, you'd want to get an amp that puts out at least 800 watts.

Hope i didn't lose you there!

[gameguru1360]

also the size power and ground wire is determined by how much power you will be running from the amp. Typically 4 gauge is standard and supports about 1000 watts. Most audiophiles will say you should upgrade to 2 or 1ga wire if you run close to that to be on the safe side, but you can get away with just 4ga. Thicker wire allows more power and you can tell when an audio system is suffering from too thin a power wire.

You should also make sure you fuse the power wire right 12" from the battery and at the amp. This will protect your electrical system like the fusebox if there is a short. Typically an 80a fuse from the battery is standard and the size of the fuse at the amp is determined by how much power. Sometimes you can match the size fuse by adding up the fuses on the amp itself.