Huge Passive Subwoofer question

[yepimonfire]

so im considering buying a 15" subwoofer, but its passive and rated at 400w RMS. well unfortunatley, i can't find a 400w or similar monoblock amplifier anywhere online. would it function with just 100w? that seems to be the highest i can go unless i want to buy some 4500 watt amplifier from pyle, but that would destroy it...

also if at all possible can someone show me where to get a monoblock amplifier thats not too expensive?

 

[MStrickland1988]

Sure you could use a 100w amp if it is clean power. The difference between 100w and 400w is only 6db. If the sub has a 90db efficency it will get to 108db with 64 watts. That is plenty of output and depending on the sub it might even distort before that.

 

[highfigh]

so im considering buying a 15" subwoofer, but its passive and rated at 400w RMS. well unfortunatley, i can't find a 400w or similar monoblock amplifier anywhere online. would it function with just 100w? that seems to be the highest i can go unless i want to buy some 4500 watt amplifier from pyle, but that would destroy it...

also if at all possible can someone show me where to get a monoblock amplifier thats not too expensive?

Look at the Dayton SA1000 from Parts Express. It's made specifically for subwoofers. You'll be going in alone on this- I have no experience with this model but it has some interesting features.

BTW- if an amplifier is rated at 4500W and it doesn't include instruction for using a dedicated circuit, it's not putting out 4500W, especially if it's not expensive. Since no electrical device is 100% efficient, doing the math for a 75% efficient amp shows that P=IE would require 4500=I(120) and through substitution, 4500/120=37.5Amperes. Considering 75% efficiency, that brings us to 50A, or 25A on a 240V circuit, which Pyle just doesn't need. This isn't a completely accurate way to calculate the power used but it's close enough to make the point.

 

[WmAx]

so im considering buying a 15" subwoofer, but its passive and rated at 400w RMS. well unfortunatley, i can't find a 400w or similar monoblock amplifier anywhere online. would it function with just 100w? that seems to be the highest i can go unless i want to buy some 4500 watt amplifier from pyle, but that would destroy it...

also if at all possible can someone show me where to get a monoblock amplifier thats not too expensive?

What is the impedance of this passive sub? Just give us a link to the product page?

-Chris

 

[WmAx]

Sure you could use a 100w amp if it is clean power. The difference between 100w and 400w is only 6db. If the sub has a 90db efficency it will get to 108db with 64 watts. That is plenty of output and depending on the sub it might even distort before that.

Only? 6dB is 2x the amplitude.

-Chris

 

[WmAx]

so im considering buying a 15" subwoofer, but its passive and rated at 400w RMS. well unfortunatley, i can't find a 400w or similar monoblock amplifier anywhere online. would it function with just 100w? that seems to be the highest i can go unless i want to buy some 4500 watt amplifier from pyle, but that would destroy it...

also if at all possible can someone show me where to get a monoblock amplifier thats not too expensive?

I can not recommend Pyle for ANYTHING. They have historically made products of the lowest possible quality and their specifications are usually works of fiction.

-Chris

 

[yepimonfire]

the impedance is 8 ohms and the unit is built for a stage, so i dont think half the amplitude is going to matter since im using it in my house someone once told me an amplifier reaches its "rating" when the volume knob is usually at half and above that it climbs such as a 110 watt amp will give you 150 if turned ALL the way up and yea i know what you mean about pyles amps, like their 4500 watt amp is if your using a 2 ohm speaker, but who the hell has 2 ohm speakers????

 

[bandphan]

the impedance is 8 ohms and the unit is built for a stage, so i dont think half the amplitude is going to matter since im using it in my house someone once told me an amplifier reaches its "rating" when the volume knob is usually at half and above that it climbs such as a 110 watt amp will give you 150 if turned ALL the way up and yea i know what you mean about pyles amps, like their 4500 watt amp is if your using a 2 ohm speaker, but who the hell has 2 ohm speakers????

There are several of 1 and 2 ohm speakers

 

[highfigh]

the impedance is 8 ohms and the unit is built for a stage, so i dont think half the amplitude is going to matter since im using it in my house someone once told me an amplifier reaches its "rating" when the volume knob is usually at half and above that it climbs such as a 110 watt amp will give you 150 if turned ALL the way up and yea i know what you mean about pyles amps, like their 4500 watt amp is if your using a 2 ohm speaker, but who the hell has 2 ohm speakers????

WIth full input voltage, truning the volume control all the way up is like putting your gas pedal to the floor and waiting for parts to fly through the hood. An amp will never produce clean power when rated output is at half and the control is at WOT.

It's not so much whether each speaker is 2 Ohms, but the load of all speakers used. Four 8 Ohm speakers in parallel is 2 Ohms and if they're mounted in the same panel, the wave front is additive, so it can act like it's larger than just four of the same drivers when they're separated.

 

[yepimonfire]

i know all of this, but im not looking to hook up 4 15" subs

 

[WmAx]

the impedance is 8 ohms and the unit is built for a stage, so i dont think half the amplitude is going to matter since im using it in my house someone once told me an amplifier reaches its "rating" when the volume knob is usually at half and above that it climbs such as a 110 watt amp will give you 150 if turned ALL the way up and yea i know what you mean about pyles amps, like their 4500 watt amp is if your using a 2 ohm speaker, but who the hell has 2 ohm speakers????

The Behringer A500 is about $200, and bridges mono to 440 watts (actual measured output by 3rd party) continuous into 8 Ohms. It has no fan; it is silent.

-Chris

 

[highfigh]

i know all of this, but im not looking to hook up 4 15" subs

I typed "400W/ch mono power amplifier" in the google search bar and got 4700 links. I don't know why you didn't find anything.

Buy a bad amp and you'll be wasting the money for the woofer. The A500 is a lot of amp for the money and I'm finishing a home theater with one now. It has no problem with driving 4 10" woofers louder than the rest of the speakers in a 8'-4" x 17' x 24' room. The SA1000 I mentioned has the advantage of parametric EQ and remote turn-on, too.

 

[mtrycrafts]

I can not recommend Pyle for ANYTHING. They have historically made products of the lowest possible quality and their specifications are usually works of fiction.

-Chris

Oh, so their name comes from Pyle it higher

 

[j_garcia]

I run my 15" passive with a Rythmik Audio A350 plate amp that is mounted in its own box.

Sorry, but to the first poster who said it is "only 6dB difference" that is saying you are going to get "only half the output". DUH. Low frequencies require MUCH more power during peak activities, so 100W for a decent 15" driver is probably not going to cut it.