Power drawn at various frequencies..

[Full Tilt 10+ year member]

Hey guys. A friend of mine had a question for me, and I really couldn't answer him. I was hoping that you guys might be able to provide an answer. At higher frequencies, his sub sounds good, and his car seems fine handling it. However, when it's digging on the low frequencies, his car's electrical really suffers - lights dim, the sub gets quieter, all that stuff. He was wondering why it pulls so much on the electrical on the lows, but not really on the high notes. Again, I didn't know exactly how to answer this question. So, why does it seem like a sub pulls harder on the lows than it does on the highs?

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[04murdalanche]

weak electrical is my best bet with no info provided at all

what sub car electrical etc...

cant really give you an answer without it

 

[Full Tilt 10+ year member]

weak electrical is my best bet with no info provided at all

what sub car electrical etc...

cant really give you an answer without it

He just drives a '99 Grand Prix, stock electrical. He runs 2 Pioneers on about 900w. He's not trying to find a solution to the problem, he just wants to know why it pulls so much on the lows, but not on the highs. I've already told him to get the big 3 a million times.

 

[04murdalanche]

[quote name='Full Tilt']He just drives a '99 Grand Prix, stock electrical. He runs 2 Pioneers on about 900w. He's not trying to find a solution to the problem, he just wants to know why it pulls so much on the lows, but not on the highs. I've already told him to get the big 3 a million times.[/QUOTE]

well you have done well sir, that would definitely help lol..

i dont know alot about power and frequency when it comes to how much and how they relate, i know @mylows10 ; can tell you though i remember him explaining it a while back.

 

[mylows10 5,000+ posts]

Your sub amp rated power is mostly done at 100 hrtz or less with a bass boost at 45 hertz Which means your amps internal parts will draw more power to produce those lower notes The lower the note the harder it is on the amp to produce it hence it needs more power to do so

 

[Falcons 5,000+ posts]

Your sub amp rated power is mostly done at 100 hrtz or less with a bass boost at 45 hertz Which means your amps internal parts will draw more power to produce those lower notes The lower the note the harder it is on the amp to produce it hence it needs more power to do so

This is what I was gonna say. Also, have him check the Lpf on the amp.

 

[Full Tilt 10+ year member]

This is what I was gonna say. Also, have him check the Lpf on the amp.

Its at 60. Good/bad? I've got no idea what an LPF is supposed to be at.

 

[itsblown 10+ year member]

It also has to do with enclosure and the specific sub. In my car its the exact opposite I only get voltage drops on higher bass notes

 

[Falcons 5,000+ posts]

Its at 60. Good/bad? I've got no idea what an LPF is supposed to be at.

Try turning it up to 80 and see if that does anything. It might be filtering out the high bass notes

 

[BrownVanMan 10+ year member]

Big 3 is needed

 

[Chriszle 10+ year member]

Could be less impedance rise at lower frequencies.

 

[T3mpest 10+ year member]

All good answers, but mostly not the MAIN reason guys.. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Look at spectrum analysis of most rap music, or music in general. You'll notice most of the big peaks are in the 40hz range. A -3db tone at 35hz draws 4x more power than a -9db tone at 60hz. Impedence is the other major factor. A box tuned at in the 30's where alot of car audio boxes are tuned as has 2 major impedence peaks, once below where most music plays (sub 20hz) and the other one usually in the 50's or 60's, anything that near that peak and your amp won't be putting out alot of power... Get near tuning, where alot of those bigger 0db type tones tend to be and the impedence rise drops.. Leading to voltage drop.

 

[Full Tilt 10+ year member]

Try turning it up to 80 and see if that does anything. It might be filtering out the high bass notes

Thanks, I'll let him know and we'll see what happens.

Big 3 is needed

That's rather obvious.

All good answers, but mostly not the MAIN reason guys.. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Look at spectrum analysis of most rap music, or music in general. You'll notice most of the big peaks are in the 40hz range. A -3db tone at 35hz draws 4x more power than a -9db tone at 60hz. Impedence is the other major factor. A box tuned at in the 30's where alot of car audio boxes are tuned as has 2 major impedence peaks, once below where most music plays (sub 20hz) and the other one usually in the 50's or 60's, anything that near that peak and your amp won't be putting out alot of power... Get near tuning, where alot of those bigger 0db type tones tend to be and the impedence rise drops.. Leading to voltage drop.

Thanks for the full answer!

 

[nu2spl 10+ year member]

All good answers, but mostly not the MAIN reason guys.. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Look at spectrum analysis of most rap music, or music in general. You'll notice most of the big peaks are in the 40hz range. A -3db tone at 35hz draws 4x more power than a -9db tone at 60hz. Impedence is the other major factor. A box tuned at in the 30's where alot of car audio boxes are tuned as has 2 major impedence peaks, once below where most music plays (sub 20hz) and the other one usually in the 50's or 60's, anything that near that peak and your amp won't be putting out alot of power... Get near tuning, where alot of those bigger 0db type tones tend to be and the impedence rise drops.. Leading to voltage drop.

yep that about covers it,the lower the freq,the more current is needed.

 

[zako 10+ year member]

The lower is the frequency, the more cone excursion and more power is required to maintain the same SPL. I have heard in the home audio DIY circles a rule of thumb is that all frequencies below 125-150Hz, consume roughly half of all power (hah, they haven't heard of cars with a 1000watt sub stage, and front speakers dangling off the stereo deck). I forgot what's the reference for this rule, it was from some book.