View Full Version : Subwoofer Question?
danny_italia
12-07-2009, 02:31 PM
Maybe Shon can answer! :)
I was just curious, let's say you have 2x 1000w subs but only 1x 1000w amp. What would be louder hooking up the amp to both subs or just one?... or would it not make a difference?
binks
12-07-2009, 03:55 PM
what type of amp and what is the impedance of the speakers?
Is it a Class D amp?
SHOmethemoney
12-07-2009, 08:27 PM
Generally two subs will be louder. Don't worry about the power ratings. Just because the sub says "1000 W", it doesn't mean that you need a 1000W amp or that the sub can really handle 1000W.
What you really need to worry about is will the subs be too low of an impedance for the amp. Too low impedance (ohms) means that more amps flow from the amp and more amps mean more heat which might mean fried amp.
Generally two subs will be louder. Don't worry about the power ratings. Just because the sub says "1000 W", it doesn't mean that you need a 1000W amp or that the sub can really handle 1000W.
What you really need to worry about is will the subs be too low of an impedance for the amp. Too low impedance (ohms) means that more amps flow from the amp and more amps mean more heat which might mean fried amp.
Ummmm.... You should always try and match amp to subs and here is why. Lets say you have a 1000wrms sub and power it with 500wrms. People almost always crank the gains and boost thinking the sub can handle it. Well all that does is cause distortion. Distortion = heat. To much heat and bye bye voice coil. The other problem is hearing distortion at low frequencies is alot harder than higher ones and add that the sub is usually in the trunk which makes hearing the distortion almost impossible.
What subs are they and which amp? Also what are the RMS ratings? The ratings you gave may be peak.
I hate subs.. Dannny! only buy meatbal or spicy itallian subs..try southwest sauce..call me you jackass
SHOmethemoney
12-08-2009, 07:19 AM
Ummmm.... You should always try and match amp to subs and here is why. Lets say you have a 1000wrms sub and power it with 500wrms. People almost always crank the gains and boost thinking the sub can handle it. Well all that does is cause distortion. Distortion = heat. To much heat and bye bye voice coil. The other problem is hearing distortion at low frequencies is alot harder than higher ones and add that the sub is usually in the trunk which makes hearing the distortion almost impossible.
What subs are they and which amp? Also what are the RMS ratings? The ratings you gave may be peak.
Keep spreading the myths.
Keep spreading the myths.
OK retard.
Does over heating a voice coil damage it? yes
Does distortion create heat? yes
does under powering a sub and turning everything up to get what you think you should have cause distortion? yes
Does distortion create heat? yes
Does over heating a voice coil damage it? yes
I did not say you could not do it. I am just saying that people blow speakers by both under powering and over powering. No myths here.
I have run 1000wrms subs on 250rms but I knew not to expect much. Now if you take a 17 year old with that set up I will bet you he will have the gains and boost cranked and distort the hell out of them.
Next?
You'll kill 100 subs over powering before you kill a single one underpowering it. This theory applies best to tweeters where the voice coil windings are very delicate.
This is an example of a good sales pitch on why a customer should buy a bigger amp when they come in to replace their sub. I've used it before and it works.
As an example, I had a real 800rms sub in my old demo/comp car with a solid 300 watts going to it. It played nothing but square waves for 5 years.
That sub is now 13 years old and still doing duty as my home theater sub with a measly 200 watts going to it.
The few subs I've seen blown from a guessed underpowered situation were typically mechanical damage as opposed to burnt voice coils.
I've never seen a sub catch fire from being underpowered, but I have repeatedly from being overpowered.
Back on topic, 1000watts with 2 subs will always be louder than with one of the same sub.
Under powering a sub will never blow it. It's the distortion or clipping that does. It also depends on the setup. For example in Hboys setup he would be ok since using a 300w amp on a 800w sub he can clip it all he wants and will never reach the thermal limits of the voice coil. now do the same with a 500w amp and run a clipped signal and see what happens. A clipped signal presents an increase in power over an AC signal by as much as 100% or more so now you 500w just became 1000w or more where the 300w amp was only 600w plus.
Again it all depends on the components used and the settings.
"Lets say you have a 1000wrms sub and power it with 500wrms. People almost always crank the gains and boost thinking the sub can handle it. Well all that does is cause distortion. Distortion = heat. To much heat and bye bye voice coil."
So, your theory was wrong here.
Also you would not get that kind of power increase from the amp. A 500 watt amp will not suddenly produce 1000 watts because it is fed a square wave. What it does do is potentially double the current output at a specific load.
Here's an example-
500 watt 4 ohm sub
250 watt amp @ 4 ohms
ported box tuned to 30hz
square wave input at 30hz
Now at the tuning frequency, the actual resisitance of the sub may be in the range of say 8-10 ohms (this is highly variable depending on a lot of factors, but it always increases at the tuning frequency). This will also be different for a sealed box.
So playing a normal sine wave the amp will only be producing about 100-125 watts. Now, feed it a square wave and this may go up as high as 250 watts. This is why all the SPL guys play square waves.
But the amp would not make 500 without changing the fuses (and all the internals for that matter). Voltage X Current = power in watts. So since the voltage is a constant here, the current draw would have to double in order to double the power output.
In my car, the amp had a 60 amp fuse running 2 - 2 ohm subs. The power output was determined by a computer model on what the resistance would be at that given frequency. I then measured the voltage output at the amp the calculate the power output.
Can't remember the exact numbers but it worked out to 290ish watts playing square waves.
Plain and simple. someone who does not know what they are doing can damage a sub with an amp that is to small therefore it is better to try and match as best as possible. We are both arguing the same point and giving the same info just written differently. I am not going to argue this.
Beacuse you think someone who doesn't know what they are doing will cause less damage with more power?
Our arguments and info are completely different.
Beacuse you think someone who doesn't know what they are doing will cause less damage with more power?
Our arguments and info are completely different.
Where did I ever say that?
Anyways. You guys are right I know nothing. Carry on.
Right here-
Plain and simple. someone who does not know what they are doing can damage a sub with an amp that is to small therefore it is better to try and match as best as possible.
So it's better to give them a bigger (better matched in your words) amp?
So, same dummy kid with your theory- 1000 watt sub + 1000 watt amp = better?
Still waiting for you to show me you know something here that I don't.
If you re-word your statement as "Someone who doesn't know what they are doing CAN blow up a sub with too small an amp and they will just do it that much sooner/better with a properly sized one" I will accept it.
Right here-
So it's better to give them a bigger (better matched in your words) amp?
So, same dummy kid with your theory- 1000 watt sub + 1000 watt amp = better?
Still waiting for you to show me you know something here that I don't.
If you re-word your statement as "Someone who doesn't know what they are doing CAN blow up a sub with too small an amp and they will just do it that much sooner/better with a properly sized one" I will accept it.
If you have a dummy kid you are screwed either way. All I am saying in straight forward terms is you are best to match the amp to the sub and set it up properly. Tell you what. Take a sub that is rated for 750w at 4 ohms. Now take and amp the is rated at 500w in 4 ohms. Now crank the gains and bass boost (like a "dummy kid" would figuring he can't blow the sub because his amp is only 500w.) and run that for a while with the volume cranked (like dummy kids do) and tell me how that works out for you. k?
In the end the difference is this. Yes a larger amp will kill the sub quicker. No question. But the smaller amp can do the same cause even though its wattage may be less than the sub the clipped signal is still over powering. If you disagree so be it. I have seen many subs blown because the "dummy kid" had a small amp so he cranked the gains etc not realizing he was clipping the amp.
Well, to make it properly short, amps don't blow subs, people do.
So taking 'dummy' out of the equation, buy the amp by how loud you want it to be and how much you are willing to spend.
I've never said you can't kill a sub with a small amp.
So, according to you, dummy kid is lulled into a false sense of security by the far superior power handling capacity of his 1000 watt sub and cranks his 500 watt amp without fear.
Question is will a 1000 watt amp make him any smarter?
No, he will still crank it and kill the sub faster.
Therefore, dummies kill subs, not small/big/any amps.
Well, to make it properly short, amps don't blow subs, people do.
So taking 'dummy' out of the equation, buy the amp by how loud you want it to be and how much you are willing to spend.
I've never said you can't kill a sub with a small amp.
So, according to you, dummy kid is lulled into a false sense of security by the far superior power handling capacity of his 1000 watt sub and cranks his 500 watt amp without fear.
Question is will a 1000 watt amp make him any smarter?
No, he will still crank it and kill the sub faster.
Therefore, dummies kill subs, not small/big/any amps.
Fine... Lets agree to that.
danny_italia
12-09-2009, 11:13 AM
I hate subs.. Dannny! only buy meatbal or spicy itallian subs..try southwest sauce..call me you jackass
Haha I've been bugging you to much lately! First the sensitivty on my alarm, then the car starter... I just thought this would be to much for 1 week! I'll stop by soon!
Ill keep watching this thread...Im staying quiet..lol.So far tims winning. You guys should be more worried about enclosure design..f3 points..then Ill jump in
And southwest sauce
mmmmm.... 12" sub with southwest.........
oh and.... Rep added.
lets throw this into the equation...
watts in an amplifier are a measurement of current output...
watts in a subwoofer are a measurement of their heat handling capabilities...
mmmm.... Monterrey cheddar bun....
lets throw this into the equation...
watts in an amplifier are a measurement of current output...
watts in a subwoofer are a measurement of their heat handling capabilities...
Well if you want to get technical about it, the current output of an amp is dependant on the heat handling of the transistors used in it.
And the thermal abilities of the sub have to do with how much current the wires in the voice coil can handle.
binks
12-10-2009, 09:34 AM
Make sure your car can actually power the amp, I learned that when I put a 15" audiobahn in my 323 when I was younger, killed the battery on the highway.
SHOmethemoney
12-10-2009, 02:20 PM
OK retard.
Does over heating a voice coil damage it? yes
Does distortion create heat? yes
does under powering a sub and turning everything up to get what you think you should have cause distortion? yes
Does distortion create heat? yes
Does over heating a voice coil damage it? yes
I did not say you could not do it. I am just saying that people blow speakers by both under powering and over powering. No myths here.
I have run 1000wrms subs on 250rms but I knew not to expect much. Now if you take a 17 year old with that set up I will bet you he will have the gains and boost cranked and distort the hell out of them.
Next?
Sure over heating a coil will damage it but distortion doesn't magically create heat.
What's to say that the guy with the 1000 watt amp won't turn up the volume causing distortion? The difference between 500 watts and 1000 watts is 3 dB. Not a huge difference is sound volume. 1 dB is considered the smallest noticeable difference. Whether the amp is 500 or 1000 watts, the user is just as likely to drive it to distortion. A 1kw amp has more potential create heat in the coil than the 500 watt amp does.
A 500 watt RMS amp will in theory put out 1000 watts when fully distorting (assuming the power supply can keep up). The 1000 watt amp will put out 2000 watts when fully distorted. The extra power is what is killing the sub not the distortion itself. Well that and the fact that most 1000 watt sub can't really handle 1000 watt RMS.
SHOmethemoney
12-10-2009, 02:28 PM
Also you would not get that kind of power increase from the amp. A 500 watt amp will not suddenly produce 1000 watts because it is fed a square wave. What it does do is potentially double the current output at a specific load.
It's true. A square wave has twice as much power as a pure sine wave. If the amp is being limited by the voltage of the rail voltage, then you could get double the power out of the amp by feeding it a sine wave and pushing the amp to fully distort. Trouble is that the voltage at the rails is likely to dip as the power supply won't be able to supply the full 1000 watts.
Leb_CRX
12-10-2009, 03:03 PM
this thread is too nerdy for me
shytstorm randy
12-12-2009, 02:45 PM
party platter on italian herbs & cheese...
how many megatrons does your sub have?
The Grey Area
12-13-2009, 04:14 AM
Big stereo = fail. You dont add weight to go fast you remove it silly
Big stereo = fail. You dont add weight to go fast you remove it silly
actually.. you fail!
If you wanna be in the 90's and have a ""big old box"..welll givver!
Like everything, styles change..and if you dont adapt..you'll fail.
Unless your doing a full out ICE car theres no need for the big boxes. I build totally fiberglass boxes with smaller drivers..(8's or 10's). the entire enclosure weighs less than 20lbs.with great sound..Its not cheap..$1200..basic. but it wieghs less than if you dated a fat chick..and makes your jdm ride sound sick!
Ive been watchin this thread, reading everyones opinions and thoughts...and as you know..I've been keepin hush! and just reading.
Ill tell ya what I know about amps,and subs!
Im gonna throw out a very bold statement! I've buit more boxes in the last 20 years than all the other car audio shops combined....period! If you wana dispute it, feel free to ask any shop..or shop owner in the city! (If you dont know me..Im not some big mouth E-turd,, know it all)
Ive seen expensive subs in bassworks boxes.. and Ive built boxes for sony subs that rip your head off!
THE INCLOSURE IS WAY MORE IMPORTANT THAN THE SUB!.. eVERY SUB HAS A BLUEPRINT CALLED ITS THIELL SMALL PERAMETERS. this is the workings of a driver.
The big problem is E-bay junkies are addicticed to specs, and the biggest deal with building a sub system is the enclosure..
I've had customers with focal subs in pre-fab sealed boxes..kicker l7's in plywood boxes.
If you learn about the customer needs...then acoustics of a design of car..what driver..A guy whos built..and undrestands,,building enclosures.thats when all the b.s of power handling doesnt matter..
Todays power ratngs are a sales pitch! Like wtf is SAE rating? IMO, my fave amps are Rockford punch 30, punch 45,(not the hd series) pheonex mps 2250. and orion hcca 225..2250.. none of those amps made more than 50 watts..except the orion., the were all rated at 30,45,50, or 100 watts. when loaded they would produce up to 1100 watts! and this ws before class "d". they were class a-b switching..
Subwoofer design (realy god subs) have so much technoligy..they can cool a voice coil thru compressed cooling..heres a paten example http://www.carsound.com/news/archives/10_16_101_2.shtml
Its all about good sounding music and wht you like..and finding a person who can deliver.
Pfft... What do you know? :)
Though I thoroughly respect your knowledge and skill shon, learn to spell... You just turned a very knowledgeable post in to a mess that is harder to read than a 2 year olds handwriting.
Though I thoroughly respect your knowledge and skill shon, learn to spell... You just turned a very knowledgeable post in to a mess that is harder to read than a 2 year olds handwriting.
Where is your "grammar cunt" signature pic? Seriously.... who the fuck cares about spelling and grammar on a forum that is full of so much bullshit.
The Grey Area
12-13-2009, 08:43 PM
Im fully aware that every sub has a preferred internal box size for optimal performance and different box types as well. I understand building proper fibreglass enclosures is a good call and would be alot lighter but Magnets on subs make them heavy as do the old mdf boxes of which you speak. I could personally never justify wasting $1200 on an enclosure. The money would be better spent actually making my car perform better and keeping my hearing. Ive done lots of work on stereos so im not just talking my ass either. My personal preference is running sans stereo and i like it. So once again Big stereo = fail ;)
Im fully aware that every sub has a preferred internal box size for optimal performance and different box types as well. I understand building proper fibreglass enclosures is a good call and would be alot lighter but Magnets on subs make them heavy as do the old mdf boxes of which you speak. I could personally never justify wasting $1200 on an enclosure. The money would be better spent actually making my car perform better and keeping my hearing. Ive done lots of work on stereos so im not just talking my ass either. My personal preference is running sans stereo and i like it. So once again Big stereo = fail ;)
Big stereo may = fail for you but everyone is different. I mean when I had my Mazda it was pretty much and entertainment centre on wheels and at the time it was what I liked. Now with my Mustang I have no intention of adding a sub other than what already there stock. Everyone has different tastes though.
The Grey Area
12-13-2009, 09:07 PM
I knoow im an opinionated poo poo head
Though I thoroughly respect your knowledge and skill shon, learn to spell... You just turned a very knowledgeable post in to a mess that is harder to read than a 2 year olds handwriting.
Your so rite! whoops
Right Shon..... THE WORD IS RIGHT!!!!!!!!! And for fuck sakes it's You're...... You really want grammaaaaar cunt an your ass again?
danny_italia
12-16-2009, 08:32 AM
on your ass again?
:P lol
:P lol
Awe fuck.... I even looked it over for any mistakes.... It was to early....
This thread has some good info in it...
I want to know know more about sine wave vs square wave and how to set that up.
SHOmethemoney
12-30-2009, 06:53 AM
Back in the day I used to use software called Cool Edit to create single tones for testing. I burnt a bunch of tones onto cd's to figure out the resonant frequency of the vehicle and used a SPL meter to figure out which frequency was loudest. The software allows you to make sine waves, square waves, triangle waves, white noise, pink noise, and a bunch of other cool effects.
I believe Cool Edit was bought by Adobe and is now part of Adobe Edition.
This thread has some good info in it...
I want to know know more about sine wave vs square wave and how to set that up.
I'm the wrong guy to ask! IMO , the best sounding music is totally analog. records, a great pre-amp and a tube amp, great wires and speakers. Sound should be kept "un-digital". Some of the best stuff is made in the 70's.
Eventually technoligy will surpass todays best electronics and some superdooper hi-speed switchin will come out that can reproduce a natural sound. The accuracy of digital (with the fill in the blanks algorithms) just doesnt sound real. The presents, the imaging.
All sound is waves or cycles (hz).
Its like the arguement that ppl only fear from 20hz to 20k hz..so add a subsonic filter so all the waisted energy an amp would use below 20 hz, would be saved. Others say that below 20hz, the body can pick up the low signals and it adds excitment to other sences...ading to the listening experience..
who realy knows whats best for your ears
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