Ive dowloaded some crazy slowed remixes by Decaf from the down for sound forum. and ive been playin them on my Fi Qs. I was showin my friend how much they flex today, and in the song i was using, theres a sweep from maybe 45 hz all the way down to god knows what (maybe 15-29hz?). when it gets down to the very bottom end of that sweep, the subwoofers, instead of osciolating like normal, just flap and sound nasty (not good nasty). Is this because its going below the Fs of the subs? It doesnt do it when i turn it down a bit, but when i crank it, it does. Is this bad/dangerous to the subs? If so, what should I do about it? thanks!
Yep. Sounds like you are playing well below tuning.
You are unloading. Playing them that low can cause problems w/ the suspension, and possible failure depending on how hard you push them. If you push them too far (excursion) you may rip the triple joint or pull the spiders from the basket....triple joint is more likely.
Yeah im not even pushing them all that hard, like on a scale of 1 to 10, 10 being full power, Id say i had them at 6 or 7. I always thought unloading only happened in ported boxes though? this is a sealed enclosure.
And i still havent fully gotten to understand subsonic, low pass, and xover yet. There are 2 settings on the amp. 1 is the gain, and the other is the filter that cuts out the higher frequencies and i have that set as low as it goes which is 70hz i believe.
A sealed box does have a 'tuning freq'. Not so much as a ported box (aka helm hertz resonance) but it does have a tuning/resonanse.
The chamber created by the sealed box can only control excursion to a given extent. Below this 'tuning' your sub will have minimal control over its excursion.
A smaller sealed chamber can help w/ controlling the sub at lower freq, but this more controlled excursion will come at the cost of a loss of low-end output.
How big is your enclosure? Seeing that your amp has no SSF and that you are playing <20hz...you may look into buying an external filter. Harrison Mods makes an in-line RCA SSF. In your case, the HPF20hz model may be just the ticket. Look for them on Partsexpress.com
ported box? If so, it's probably unloading from hitting below the tuned port frequency. If it's sealed, you're probably at the sub's Fs, which would be where it's most efficient, so power output increases as the impedance drops.
DO NOT LISTEN TO CanaanWhite... "Turn your gain to 3/4 and bass boost all the way up and set you subsonic at 15hz.....thats how I set all my amps and they sound just fine"
NEVER do this... Set you gain with a meter, it should be around your output voltage from your HU... Subsonic filter is to set the cut point for your roll off frequency...
If you don't have a meter my way works...I read this in a Kicker book...so I know its right but you will be able to get more accurate reading with a meter...I set mine by ear...i keep turning all the gains and levels up till it distorts then back them down just a little...when you adjust your gains set your radio volume at 3/4 and EQ or Tone controls flat that mean zero....then adjust out your amp...adjust till it distorts then back up about a 10th...after that adjust your radio EQ or tones and your set
okay have fun blowing your sh*tty little comps canaanwhite.
I may only have a year of experience but i sure as hell know enough not to listen to that.
@Glass Wolf - It is a sealed box
@Ricky Lussier - Where can i get a meter? My amp only has a gain and a low pass filter (I think thats waht its called.). I just have the gain turned all the way up on my amp and then i adjust it from the head unit's subwoofer level setting.
WOAH! the gain should never be turned all the way up... it should be matched to your HU, if your HU is 2volt then 2 volt for your gain, you just need a multi meter to figure it out...
Canaanwhite's way will work if you a weekend warrior with your system and you dont know much about it and want a quick fix. I've done it for years with good results. You don't have to get carried away with doing all this to a T.
it will work, but it is like taking a cherry 69 Camaro with a stock engine and slapping a super charger on it. Yes it will work, however you could blow the motor, or do other damage, or perhaps not get that much increase and not reach full potential. There are so many other things needed to be done then to just slap it together. Do it right and it will last longer, run better and have better performance... Same with the amp, do it wrong you could blow the subs, hit some major clipping really easy, not achieve full potential or ruin the amp....
wow what? i got stuck with a buick lesabre from my gramma and i wanted to get the most out of it so i did a top swap with a L67. its not uncommon to do, but the L67 had some miles on it so the heads were probably on their way out already.
Okay so according to that chart, I have a 3000 watt amp running 1ohm, so I should see 54.77v AC?
and i know to turn loudness off and the bass/mid/treble on the eq eq to the +/-0 setting , but should i turn the subwoofer level on the head unit to 0 too? (it goes from 0-8). and i dont know how to turn off the filters
alright cool. any idea on the filters? i know theres a low pass on the amp so i guess i just turn that all the way up to what ever the max is (I think its like 2 or 300hz)? and theres a setting in my head unit that makes the line out mode for rear or subwoofer (so i guess this another low pass so would i just turn it to the rear setting so it sends out a full range?