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New member Username: Us1Post Number: 1 Registered: Jan-07 | I have ordered a 250/1 amp and 2 10" JL marine subs that are rated 150W rms @ 4 ohms. BTW, these are designed and will be installed as free air subs in my boat. I have no room for boxes. I originally wanted to order the 500/1 amp, but my JL dealer said that was overkill and the 250 would be a better choice. So that is what is ordered. I talked with the JL tech guy and he recommended the 250 over the 500 also. I don't understand how a 250 amp will be enough for 300 w subs (2 x 150w) I didn't understand either guy fully as I don't know all the technical terms, so I got lost/confused. A boating site I participate in all reccomended the 500 saying the 250 would be under powered. Some of those replies came from very knowledgable guys in the audio field. So now I have conflicting info and am looking here for clarification in very simple terms (that's were I get lost) on your guys opinion between the 2 amps. I pick it up in a day or so and might step up to the 500. I'm not into the load bass boom, rap music. More after the qaulity sound of todays hits, hip hop, country and the likes. Not looking to upgrade at a later time, so looking for the best amp for these 2 subs. Thanks, if more info is needed, please ask. Jerry |
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Bronze Member Username: Notoriousroc1Post Number: 18 Registered: Jan-07 | i have that same amp with an old Alpine Type-R 300W sub. Once my knukonceptz wires get here i'll install them (probably friday). The thing is, JL underrates their amps by a little bit; not as much as RF and Kicker, but I think the JL 250/1 can get pretty damn close to 300W. But, I would go with the 500/1 because it has more of a buffer in wattage. that way you wont clip your signal from the amp. but, the 250/1 will still push them pretty good anyone wanna add anything to this??? |
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Gold Member Username: MixneffectOrangevale, Ca. USA Post Number: 1400 Registered: Apr-05 | Jerry, I agree JL underrates their amps, but thats not the reason you should use the 250/1 amp for those subs. You want to use them in free air, right? Well in free air you will have very little suspension resistance against the cone as opposed to being in the box. If you power up a speaker in free air with full power (RMS), you will overdrive them and probably damage them. Sure you can use the 500/1 amp and just be carefull with the volume button, but why take the chance of having your subs damaged by someone else when they are turning the volume up when you are unaware. I would say that this would be cheap insurance. Sealed boxes provide the most suspension resistance and may be powered above the RMS rating of the speaker because the cone will not be overdriven. |
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New member Username: Us1Post Number: 2 Registered: Jan-07 | So that's 1 for the 500, 1 for the 250. ;) mixneffect, That brings up another discreptancy in the info I've been getting. My dealer also mentioned the free air use of the subs require less power because of no resistance, but another person said they actually take more power in free air, because in a box you get some power benefits from the rebound of the cone. I'm just not quite sure on that one, but counted on his knowledge, as I have none on this. I take it that both amps will be fine and perform the 'exact same' up to a volume level, at which time the 500 will perform abit better at higher levels? I'm assuming the difference won't be noticable until the volume is near the top. I'm installing these subs and amp, along with a 300/4 amp for the highs to replace the single 50-4 MTX Blue Thunder that came in the boat when purchased, I think this should be a big improvement. So the risk of too much power to the subs with the 500 is the only reason to stay with the 250? FWIW, Other people don't mess with our stereos, so the chance of someone else turning it to high is unlikely. Thank You both. Jerry |
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Gold Member Username: MixneffectOrangevale, Ca. USA Post Number: 1402 Registered: Apr-05 | " but another person said they actually take more power in free air, because in a box you get some power benefits from the rebound of the cone" Totally untrue. In a box you get more volume, not power. By the way, you get very little more volume by pushing 500 watts instaed of 250 or 300 watts into a given speaker (than can actually handle the extra power). Remember, Watts are a unit of measure for the power you push into a speaker, not volume. Decibels (dB's) are the unit of measure for loudness/volume. One more thing. Watage handling is a limit, not a goal. This means that you should not turn the volume past that given wattage rating. If you do, it will overdrive the speaker, and will not necessarily yield more volume. It will however distort the sound, and even damage the speaker. |
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Silver Member Username: Dsmith07LaGrange, NC US oF A Post Number: 419 Registered: Jun-06 | i got the 500/1 and i love it, nice amp! |
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Gold Member Username: MixneffectOrangevale, Ca. USA Post Number: 1403 Registered: Apr-05 | https://www.ecoustics.com/electronics/forum/car-audio/306822.html https://www.ecoustics.com/electronics/forum/car-audio/284611.html#POST915100 https://www.ecoustics.com/electronics/forum/car-audio/189437.html#POST579893 https://www.ecoustics.com/electronics/forum/car-audio/131798.html#POST293778 https://www.ecoustics.com/electronics/products/articles/109138.html |
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Gold Member Username: MixneffectOrangevale, Ca. USA Post Number: 1404 Registered: Apr-05 | https://www.ecoustics.com/electronics/forum/car-audio/310162.html#POST993844 |
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New member Username: Us1Post Number: 3 Registered: Jan-07 | mixneffect, Thank you! Hopefully not to much of a bother. I have spent countless hrs researching on this board over last several days since I ordered the amps. But unless you know what to look for, very little gained. Sounds like the 250 will be just fine then. The power between the 2 amps really comes into play here, or should I say makes very little difference. Jerry |
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Gold Member Username: MixneffectOrangevale, Ca. USA Post Number: 1408 Registered: Apr-05 | Personally I am in favor of matching up an amp to a speaker that has 10-20% headroom. It is because it allows the amp to fully power your speakers and not be driven to its max as the speaker gets its fill. The extra 10-20% is an opinion, not a fact, but it does help a lot. Most cheap amps distort quite prematurely, so if you underpower your speakers and run the amp full blast, you will distort the sound, damage your amp, and speakers. JL is not a cheap amp (build wise), so it will have better control. In your case I would go with the 250 instead of the 500. |
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Gold Member Username: N2audioLawrence, Ks USA Post Number: 1141 Registered: Mar-04 | 2nd the 250/1. If you had more powerful subs, or were planning to use a sealed enclosure I might lean toward the 500, but why spend the extra money when all you'll really gain is the likelyhood of damaging the subs. |
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New member Username: Us1Post Number: 4 Registered: Jan-07 | Thanks. Everyones input is very much appreciated. I'll stay with the 250/1 now. |