Subwoofer/Amp
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Subwoofer/Amp Would it affect the sound quality if subwoofers are underpowered by the amplifier? For example: 2 300 watts RMS subs powered by a 150x2 watts RMS amp. Since the subs are only half powered would this affect the sound quality of the bass when you turn it up pretty loud?
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Rep Power: 0 Since it takes double the power to get 3 more db of volume you will be quite fine.
Amps put out from 0 to the max wattage and it varies continuously between those two values. More power means more volume from the speaker. Max power is the rating of the amout of power the amp can output in short burst. RMS is the amout of power the amp can output all day long if it wanted to. The same applies to speakers. Speakers come rated w/ a sensetivity, for example 87db w/ 1 watt @ 1 meter. This means in a perfect setup the speaker will be 87db loud 1 meter away powered w/ 1 watt of power. To get 90db, the amp needs to put out 2 watts, for 93db 4 watts, for 96db 8 watts, etc.... So most time the amp wouldn't need to use more than 100 watts anyway. As long as you don't try to make it super loud you will be fine.
Honestly I used to use an old Soundstream 90x2 (max power) amp to power a pair of Soundstream SPL12's for years. I got it metered at 128db. Not too bad for a pair of subs on only 180 watts of total power.
Amps put out from 0 to the max wattage and it varies continuously between those two values. More power means more volume from the speaker. Max power is the rating of the amout of power the amp can output in short burst. RMS is the amout of power the amp can output all day long if it wanted to. The same applies to speakers. Speakers come rated w/ a sensetivity, for example 87db w/ 1 watt @ 1 meter. This means in a perfect setup the speaker will be 87db loud 1 meter away powered w/ 1 watt of power. To get 90db, the amp needs to put out 2 watts, for 93db 4 watts, for 96db 8 watts, etc.... So most time the amp wouldn't need to use more than 100 watts anyway. As long as you don't try to make it super loud you will be fine.
Honestly I used to use an old Soundstream 90x2 (max power) amp to power a pair of Soundstream SPL12's for years. I got it metered at 128db. Not too bad for a pair of subs on only 180 watts of total power.
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Rep Power: 0 Generally the more power you get, the louder and a woofer CAN play. I would suggest getting the biggest possible class d amp you can afford. It will be cheaper and you will get more power. Something like the JBL 600.1, MTX 6500d, etc. sounds like it would work well. Most amps like that will get you about 600rms/1200max (300/600 per sub) and will cost around $200 to $250 off ebay.
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It's highly recommended to not underpower subs. You will have a much greater chance of driving the amp into clipping and wrecking your sub, because as you turn the volume up, the amp will become much more distorted as the sub will still be wanting more power, and eventually clip and you will be up **** creek without a paddle.
I HIGHLY recommended matching the power of the subs and amp, or even overpowering if you have to. You are better off overpowering than underpowering, even though that may sound wrong and people may disagree with me, this is a known fact among audiophiles.
I HIGHLY recommended matching the power of the subs and amp, or even overpowering if you have to. You are better off overpowering than underpowering, even though that may sound wrong and people may disagree with me, this is a known fact among audiophiles.
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From: masawchewsets
Rep Power: 0 Very true megahurtz I had a eartquake 300w amp on my (2) 8" bostons 2ohms, and it always started clipping on me I ran the recommended 500w a test amp and sounded much better I had one and got rid of it but I am going to get A JL 1000/1 or one of the new boston amps both about the ame price.
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Rep Power: 0 Underpowering is a total myth. If it were true everyone would be blowing speakers all the time.
For example, if you have a 500 watt speaker on a 500 watt amp. When the volume is at 0, your outputting 0 watts to the sub. Put the volume up half way and your probably putting out 75 watts if that. Turn it up all the way and then you'll be getting a full 500 watts. Remember volume is logrithmic. Each 3 more db of volume takes double the current amount of power. So your only using lots and lots of power when the volume is really cranking.
The gains match an amp to sub and the HU. If the gains are set properly there should never be a problem. When the HU gets to about 85% max volume, the gain should be set so that the subs are as loud as can be before clipping starts. Since this is where clipping starts then the user shouldn't ever go past this volume. Problem solved. Its basically impossible to blow them.
I've been in car audio a long time and have never powered speakers w/ their full power until last summer. I ran a pair of Soundstream SPL 12's off a 90x2 (max power) amp for over 10 years, and now my gf has them in her car. Still thumping away and doing about 128db. Not too bad but they can get louder w/ more power for sure w/ a solid 400 watts or so each.
The problem is with kids who get a 500 watt speaker and a 400 watt amp. They think they can just max the gain **** and not worry since they shouldn't be able to blow the speaker. This is totally untrue. The problem is w/ the gain wide open they allow the amp to be able to go into clipping really bad. When an amp clips it can easily put out double or more than its' rated power in a clipped and distorted signal. Now that 400 watt amp is putting out 800+ watts of crap power. One word, boom .... blown sub.
In the end though more power generally equals more volume. If you want lots of volume get lots of power. But don't be afraid of underpowering subs either.
For example, if you have a 500 watt speaker on a 500 watt amp. When the volume is at 0, your outputting 0 watts to the sub. Put the volume up half way and your probably putting out 75 watts if that. Turn it up all the way and then you'll be getting a full 500 watts. Remember volume is logrithmic. Each 3 more db of volume takes double the current amount of power. So your only using lots and lots of power when the volume is really cranking.
The gains match an amp to sub and the HU. If the gains are set properly there should never be a problem. When the HU gets to about 85% max volume, the gain should be set so that the subs are as loud as can be before clipping starts. Since this is where clipping starts then the user shouldn't ever go past this volume. Problem solved. Its basically impossible to blow them.
I've been in car audio a long time and have never powered speakers w/ their full power until last summer. I ran a pair of Soundstream SPL 12's off a 90x2 (max power) amp for over 10 years, and now my gf has them in her car. Still thumping away and doing about 128db. Not too bad but they can get louder w/ more power for sure w/ a solid 400 watts or so each.
The problem is with kids who get a 500 watt speaker and a 400 watt amp. They think they can just max the gain **** and not worry since they shouldn't be able to blow the speaker. This is totally untrue. The problem is w/ the gain wide open they allow the amp to be able to go into clipping really bad. When an amp clips it can easily put out double or more than its' rated power in a clipped and distorted signal. Now that 400 watt amp is putting out 800+ watts of crap power. One word, boom .... blown sub.
In the end though more power generally equals more volume. If you want lots of volume get lots of power. But don't be afraid of underpowering subs either.
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Originally Posted by irishtemper
my bostons recommend 50-500w RMS if i go below that 50w It will cause problems
Go take a volt meter and put it across the amp leads and start turning up the volume. You'll be amazed at how little power you actually use on a regular basis. Its an exponential relationship (power vs volume). So at first your really not using much power at all. Even w/ the volume half way.
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Rep Power: 0 Setting the gains ............... heres how I would set the gains.
1) Set the deck flat. No EQ, Bass boost, Loud, and no Bass or treble.
2) Turn the gains down all the way on all the amps.
3) Now unhook all the speakers from the amps, except the fronts. Remember to have it off when hooking and unhooking the speakers.
4) Turn the deck up to about 85% of the max volume. This should be a good point that gives a lot of volume control and also is close the the output potential of the deck. This will be your new max volume that you don't wanna go past.
5) Turn up the front gain until the speakers just start to distort and back off just a tad.
6) Now unhook the fronts and hook the rears back up.
7) Turn up the rear gain until the speakers just start to distort and back off just a tad.
8) Now unhook the rears and hook the subs back up.
9) Turn up the sub gain until the speakers just start to distort and back off just a tad.
10) Now hook all the speakers back up.
The key to understand is now every speaker in the car should be maxing out, be undistorted, and getting as loud as it can at the 85% volume mark. Think of this as the new max volume.
Now the next thing to do is to tune the system. Everything maxes out at the same time and is as loud as it can be, but that might not be the best. Whatever speaker is drowning others out, turn that gain down. For example, say the rears are overpowering the fronts. Then you need to turn the rear gain down so that it isn't as loud as compared w/ the fronts. Any tuning here should be by turning the gains DOWN only since they should already be as high as they can go.
From here you can add in bass or treble, but +2 at the most. Preferably none at all. And no on the bass boost, loud, etc. Those are just bad news.
Good luck.
1) Set the deck flat. No EQ, Bass boost, Loud, and no Bass or treble.
2) Turn the gains down all the way on all the amps.
3) Now unhook all the speakers from the amps, except the fronts. Remember to have it off when hooking and unhooking the speakers.
4) Turn the deck up to about 85% of the max volume. This should be a good point that gives a lot of volume control and also is close the the output potential of the deck. This will be your new max volume that you don't wanna go past.
5) Turn up the front gain until the speakers just start to distort and back off just a tad.
6) Now unhook the fronts and hook the rears back up.
7) Turn up the rear gain until the speakers just start to distort and back off just a tad.
8) Now unhook the rears and hook the subs back up.
9) Turn up the sub gain until the speakers just start to distort and back off just a tad.
10) Now hook all the speakers back up.
The key to understand is now every speaker in the car should be maxing out, be undistorted, and getting as loud as it can at the 85% volume mark. Think of this as the new max volume.
Now the next thing to do is to tune the system. Everything maxes out at the same time and is as loud as it can be, but that might not be the best. Whatever speaker is drowning others out, turn that gain down. For example, say the rears are overpowering the fronts. Then you need to turn the rear gain down so that it isn't as loud as compared w/ the fronts. Any tuning here should be by turning the gains DOWN only since they should already be as high as they can go.
From here you can add in bass or treble, but +2 at the most. Preferably none at all. And no on the bass boost, loud, etc. Those are just bad news.
Good luck.
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From: masawchewsets
Rep Power: 0 So if its untrue why don't i run my subs right off the head unit??????????? It's what 35w.? also if the rear is overpowering the fronts you don't have to turn down the gain.....................Just set the fader all the way to the front and go back a little at a time till the rears are audible you don't actually need rear speakers.
Originally Posted by Regularjoe
Setting the gains ............... heres how I would set the gains.
1) Set the deck flat. No EQ, Bass boost, Loud, and no Bass or treble.
2) Turn the gains down all the way on all the amps.
3) Now unhook all the speakers from the amps, except the fronts. Remember to have it off when hooking and unhooking the speakers.
4) Turn the deck up to about 85% of the max volume. This should be a good point that gives a lot of volume control and also is close the the output potential of the deck. This will be your new max volume that you don't wanna go past.
5) Turn up the front gain until the speakers just start to distort and back off just a tad.
6) Now unhook the fronts and hook the rears back up.
7) Turn up the rear gain until the speakers just start to distort and back off just a tad.
8) Now unhook the rears and hook the subs back up.
9) Turn up the sub gain until the speakers just start to distort and back off just a tad.
10) Now hook all the speakers back up.
The key to understand is now every speaker in the car should be maxing out, be undistorted, and getting as loud as it can at the 85% volume mark. Think of this as the new max volume.
Now the next thing to do is to tune the system. Everything maxes out at the same time and is as loud as it can be, but that might not be the best. Whatever speaker is drowning others out, turn that gain down. For example, say the rears are overpowering the fronts. Then you need to turn the rear gain down so that it isn't as loud as compared w/ the fronts. Any tuning here should be by turning the gains DOWN only since they should already be as high as they can go.
From here you can add in bass or treble, but +2 at the most. Preferably none at all. And no on the bass boost, loud, etc. Those are just bad news.
Good luck.
1) Set the deck flat. No EQ, Bass boost, Loud, and no Bass or treble.
2) Turn the gains down all the way on all the amps.
3) Now unhook all the speakers from the amps, except the fronts. Remember to have it off when hooking and unhooking the speakers.
4) Turn the deck up to about 85% of the max volume. This should be a good point that gives a lot of volume control and also is close the the output potential of the deck. This will be your new max volume that you don't wanna go past.
5) Turn up the front gain until the speakers just start to distort and back off just a tad.
6) Now unhook the fronts and hook the rears back up.
7) Turn up the rear gain until the speakers just start to distort and back off just a tad.
8) Now unhook the rears and hook the subs back up.
9) Turn up the sub gain until the speakers just start to distort and back off just a tad.
10) Now hook all the speakers back up.
The key to understand is now every speaker in the car should be maxing out, be undistorted, and getting as loud as it can at the 85% volume mark. Think of this as the new max volume.
Now the next thing to do is to tune the system. Everything maxes out at the same time and is as loud as it can be, but that might not be the best. Whatever speaker is drowning others out, turn that gain down. For example, say the rears are overpowering the fronts. Then you need to turn the rear gain down so that it isn't as loud as compared w/ the fronts. Any tuning here should be by turning the gains DOWN only since they should already be as high as they can go.
From here you can add in bass or treble, but +2 at the most. Preferably none at all. And no on the bass boost, loud, etc. Those are just bad news.
Good luck.
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Originally Posted by irishtemper
So if its untrue why don't i run my subs right off the head unit??????????? It's what 35w.?
HU: 50 watts, 50Hz-20kHz, 5% thd
Amp: 50 watts, 20Hz-20kHz, 0.05% thd
So a 50 watt HU vs a 50 watt amp is a night and day difference. The HU doesn't put out much power, especially in the 20Hz to 50Hz region, right where the subs want to play. Plus look at the thd spec, a HU has mathematically 100% more distortion as the amp when it puts out that 50 watts.
If a sub has an efficiency of 87db, then w/ cabin gain etc. you'd probably get it to be about 95db if you measured it 1 meter away.
1 watt = 87db
2 watts = 90db
4 watts = 93db
Originally Posted by irishtemper
also if the rear is overpowering the fronts you don't have to turn down the gain.....................Just set the fader all the way to the front and go back a little at a time till the rears are audible
Originally Posted by irishtemper
you don't actually need rear speakers.
Last edited by Regularjoe; Jun 3, 2004 at 08:55 PM.
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