Qtr

I have a 12 inch woofer that is rated at 250 watts RMS and 500 watts max at 4 ohms. I'm thinking of getting an amp that is 1000 watts max but it also says:
- 165W x 2, 20Hz - 20kHz, @ 0.04% THD + N, at 4 Ohms
- 200W x 2, 20 - 20kHz, @ 0.15% THD + N, at 2 Ohms
- 400W x 1, 20Hz - 20kHz, @ 0.1% THD + N, at 4 Ohms

Does this mean if I bridge both channels the sub would be getting 400 RMS? I know this isn't always exact, so I'm wondering if it would be safe to hook this up.

MadMax07SL

Yeah, you'd be overpowering it...

ekrunch

Can you tell us more about the woofers configuration? Single or dual voice coil? 2 ohm or 4 ohm? (Per voice coil) It doesn't look like that amp is 2 ohm mono stable so if you have a dual 4 ohm voice coil then you're not going to be able to get optimal power from your amp. If it's a single voice coil 4 ohm then it looks like you're going to be delivering 400w to that 250w woofer, which is more power than you need and that can be a bad thing.

Depending on the quality of the woofer, sometimes you can get away with over powering as long as you don't abuse it! I had a pair of JL Audio W4-D4 15's which were rated for like 400w RMS each. I had them running bridged on an 1800w Hifonics Series VIII Colossus and it was absolutely amazing, you just couldn't abuse it. You had to give the woofers a chance to cool off so it wasn't good for "street bass" situations where you're just driving around ground pounding for long periods of time. I'm just saying that if you keep your volume **** under control and the gains on the amplifier are set properly so you're not distorting it, you can get away with some things. 400w RMS on a 250w RMS woofer isn't that out of the ordinary.

AscendantMax

iTrader: (7)

I HIGHLY doubt you sent a true 1800 watts to your subwoofers. If you did, the coils would have reached their thermal limit and go up in smokes...

OP, you should be fine with that amp, just be smart with the tuning.

SteveB123

iTrader: (2)

Do some more reading about music amplification.
Just because you have an amp capable of producing X watts, doesn't mean it ever will send that to a driver for any length of time.

Remember log scales?

ekrunch

Well, that's what the amp was rated (1800x1 RMS @ 4ohm/14.4v) for and I had the electrical system to drive it, so I've got to go with what I know. This was also back in the early 90's when Hifonics was one of the best amps you could buy. (Series VIII, before they got bought out by Maxxsonics) But yeah, I never played it for more than a few songs straight. It was a competition system that didn't get used all that much and I only had that amp in place for about a month.

Anyway, back to the original topic. I wasn't trying to brag or go too far off topic, just stating an example that sometimes it's not always about the numbers and that 400w on a 250w sub will probably be fine as long as you pay attention to distortion, gain levels, etc.

AscendantMax

iTrader: (7)

ohhh, then that's a different story.

i thought you were referring to the newer hifonics stuff.

Qtr

In response to ekrunch, i would be powering http://www.sonicelectronix.com/item_...JH4512-04.html
with http://www.qvusa.com/product_info.ph...d32650ec714382.

I was given the speaker, so I'm searching for an amp, but it's hard to find one that matches up with the specs of the sub that's not too expensive.

And I understanding what you're saying SteveB, but I'd rather not spend money on an amp that has the capacity of ultimately blowing the sub.

ekrunch

You'll probably be fine with this setup. If you're keeping the stock head unit, make sure to use a good quality line output converter. Distortion will blow that speaker before an extra 150w of power will! Also, spend the money on a good box that is the right airspace. A good box goes a long way in making things sound good.

Batxel

iTrader: (1)

Distortion does NOT blow speakers. Speakers don't know what distortion is only your ears do. Too much power over time kills speakers plain and simple.

MadMax07SL

No, distortion will destroy a speaker long before a quality over powered system will...

Car Addict

That amp is probably over rated. Just be careful with the gain.

Goomz

iTrader: (1)

distortion can and will blow speakers. same with a clipping amp, aka overpowering of the speakers, aka audible distortion...which is basically the SAME THING.


but op, your setup will work. just tune your amp correctly. and do not use a cheap $30 line out converter. you do get what you pay for, esp in he audio world. i made a thread on how to do this on here somewhere...ill try to find it.

edit : heres my quick how to set your amp gains thread http://forums.maxima.org/audio-elect...mp-sticky.html

AscendantMax

iTrader: (7)

Distortion will NOT kill a speaker. You may OVERPOWER a speaker to the point of it reaching xmech, causing it to play a nasty buzzing sound. Prolong OVERPOWERING can kill a speaker.

No speaker will die if you sent a clipped signal (doesn't necessarily mean overpowering a speaker) that is BELOW the speaker's rated power. I can send 50 watts of clipped signals to a speaker...that can handle 500 watts rms for example, and it will just play a nasty sound. but will the coils fry? no.

Goomz

iTrader: (1)

so your telling me that if you have say a 4" door speaker and is reaching xmech due to too much bass being driven into it that its not going to blow out due to distortion??

Batxel

iTrader: (1)

No it is NOT the same thing. Distortion is when there is difference between the orignal signal and what your ears hear. Overpowering a speaker is going over the mechanical and thermal limits of the speaker. You can send a 50w clipped signal all day long at 300w speaker not blow anything try it yourself.

Where did you come up with this theory?????? Speakers don't have feelings like 'hey I love this signal it feels soooo good to me' all they see is current not quality.

MadMax07SL

I understand what you're saying as a theory, but in the end I think we should consider real life application over theory. It's rare that anyone grossly under powers a car speaker, especially to the degree you're referencing. So for all purposes, we should assume that most speakers are going to be near or over their rating on some regular basis.

A distorted signal with enough wattage will exert a speaker more then the same wattage of a clean signal, therefore it's safe to say that prolonged playing with excessive distortion can and does damage speakers as compared to the same power that's clean.

Batxel

iTrader: (1)

All amplifiers put out a certain amount of distortion. My point is that it is not the distortion that kills the speaker it's really the power. I assume you are trying to say a clipping amplifier that is rated at the same rating of speaker can kill a speaker than yes that is possible. Once you drive an amp to or close to clipping it's going to put out significantly more power over time than it would normally. If both a distorted signal and clean signal is putting out the same exact wattage the speaker will last just as long.

AscendantMax

iTrader: (7)

goomz, I never said overpowering a speaker will not kill a speaker. Once you exceed the coil's thermal limits, it will die. Plain and simple. But it will never burn up when underpowered and clipped.

locknuts27

iTrader: (2)

Personally I would have an amp that will over power rather than under power as you can turn the gain down to minimize the output power.

All amps are under rated, rms equals .707 and times that of the max power 1000 watts it comes to 707 watts. Google it!

Wouldn't get a 1000 max watt amp, try to look for 500 watt rms amp. Don't buy an amp based on max power rather by continuous or rms power.

Far as distortion goes, 1% of distortion won't kill the speaker. Most amps have pretty low distortion levels. His amp only puts out .1% so I don't even think you will even hear the distortion.

Bridging would be only going in to single channel thus 400 watts x 1 ch.