Which gain setting would be correct?

[Fuzion64]

I know this is a noob question, but I have two 12" Kicker Comp VT's rated at 400RMS/800 peak each

Is it safe to set my gain for 800w given the fact I have two subwoofers or would I risk blowing out the subwoofers eventhough the power should divide among the two? Can I actually give 800w (28.28v) of power or should I only set the gain for the RMS of say 1 sub at 400 watts (20.0v).

I'm not sure if I need to use 28.28v or 20.0v to get the best bass out of my system for the subs I have.

Click to read more...

 

[afearlesshunter]

You should look at what the amplifier you are going to use can produce first. What is the amp?

 

[Fuzion64]

kenwood KAC-9106D. It has 120Amp of fuses and I believe the actual rms is 900w last time it was checked, but I have reconfigured it since then.

 

[Dbzforlife]

kenwood KAC-9106D. It has 120Amp of fuses and I believe the actual rms is 900w last time it was checked, but I have reconfigured it since then.

If it puts out 900w rms then that would be a extra 50w over there rms rating. As long as the amp isn't clipping the subs should be fine. Someone could correct me if I'm wrong.

 

[Fuzion64]

When testing to set it with a multimeter do you use vdc 200 or vac 200 voltage?

some youtube videos say vdc and some say vac so I want to know which one is correct when dealing with car audio.

 

[Dbzforlife]

When testing to set it with a multimeter do you use vdc 200 or vac 200 voltage?
some youtube videos say vdc and some say vac so I want to know which one is correct when dealing with car audio.

Apologies, I misread the question you where asking. This one is above my head. Will have to wait for someone to chime in, I'll be staying tuned in.

 

[Jeffdachef 5,000+ posts]

When testing to set it with a multimeter do you use vdc 200 or vac 200 voltage?
some youtube videos say vdc and some say vac so I want to know which one is correct when dealing with car audio.

the signal the amplifier puts out is AC voltage aka alternating current. Set the amp for the full 900, you wont even see 450 watts after box rise.

 

[Fuzion64]

I had one more question concerning bass boost and gain.

Now I know you are not supposed to use bass boost, but with the gain at 28.0v giving off 800w

The bass is just weak until I add the bass boost back in, but I am afraid to now since people say bass boost is bad. There is a thump, but no hard hitting bass until I turn the bass boost up a little. I feel like I'm listening to regular speakers basically. The thump just isn't there without the bass boost I can't feel the bass slam. I can hear it but I can't feel it anymore with 0 bass boost.

My bass boost goes up to 18db on my amp. I was a little shocked when I went to adjust my amp the first time myself, because when I put the truck in the shop to have the system installed I noticed the guy set my bass boost for 18db, but turned the amp gain way down to compensate for the distortion. Was this okay to do aslong as he was compensating for the distortion by keeping the gain down? I'm someone who likes to feel the bass slam and he knew it. I told him I liked hard hitting bass. The bass would hit so hard on two shallow kicker comp vt's you couldn't even use the rear view mirror. I loved it that was such a great setup for me. Then I went and started adjusting stuff by turning off the bass boost and setting the gain for 28.0v with no boost and the hard hit is gone.

Is it safe to use the bass boost the way he had it at 18db so long as I turn the gain way down to compensate for the distortion and added boost?

So now for my question: if 28.28v is 800w, and I want to use some bass boost to feel the actual hit. What should my baseline gain voltage be set at before I even start adjusting the bass boost. Without bass boost I would be shooting for 28.0v, but now I have to compensate for the new figures with bass boost and out of 18db what is the maximium amount of bass boost I should use while lowering the gain to compensate for the boost and distortion?

 

[crosjr 10+ year member]

Try setting the gain with a -6db tone and see if that helps. I would even try a -10db tone before using that bass boost.

 

[n2audio 5,000+ posts]

Cranking the boost has the same effect as cranking the gain except boost is focused at a certain frequency (40hz on that amp). So a lot of boost will still distort/clip the amp just like too much gain, but only at a particular frequency. So if you're cranking ~18dB of boost at 40hz then it's going clip at 1/2 (or less) volume at that frequency (with some degree of roll off) while 30 and 50-100hz is not only not at the same level, it's at a level so much lower it's effectively attenuated.

It makes no sense. If you think you're lacking output just kick the gain up a little, try it again with a -3dB tone.

I think what it comes down to is these dmm gain settings are intended to provide a relatively flat frequency response in the system. If you've come into the hobby cranking up bass settings on everything you've ever listened to - you've trained yourself to expect boom at all volumes of all music -- that's not how music is supposed to sound -- so setting it up right doesn't sound "right" to you.

I guess set it so it sounds right to you, but be careful at high volume.

 

[n2audio 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/redface.gif.62fdbfe1a101588a808c4cff71bcb942.gif

 

[Jeffdachef 5,000+ posts]

I had one more question concerning bass boost and gain.Now I know you are not supposed to use bass boost, but with the gain at 28.0v giving off 800w

The bass is just weak until I add the bass boost back in, but I am afraid to now since people say bass boost is bad. There is a thump, but no hard hitting bass until I turn the bass boost up a little. I feel like I'm listening to regular speakers basically. The thump just isn't there without the bass boost I can't feel the bass slam. I can hear it but I can't feel it anymore with 0 bass boost.

My bass boost goes up to 18db on my amp. I was a little shocked when I went to adjust my amp the first time myself, because when I put the truck in the shop to have the system installed I noticed the guy set my bass boost for 18db, but turned the amp gain way down to compensate for the distortion. Was this okay to do aslong as he was compensating for the distortion by keeping the gain down? I'm someone who likes to feel the bass slam and he knew it. I told him I liked hard hitting bass. The bass would hit so hard on two shallow kicker comp vt's you couldn't even use the rear view mirror. I loved it that was such a great setup for me. Then I went and started adjusting stuff by turning off the bass boost and setting the gain for 28.0v with no boost and the hard hit is gone.

Is it safe to use the bass boost the way he had it at 18db so long as I turn the gain way down to compensate for the distortion and added boost?

So now for my question: if 28.28v is 800w, and I want to use some bass boost to feel the actual hit. What should my baseline gain voltage be set at before I even start adjusting the bass boost. Without bass boost I would be shooting for 28.0v, but now I have to compensate for the new figures with bass boost and out of 18db what is the maximium amount of bass boost I should use while lowering the gain to compensate for the boost and distortion?

let me guess. You used a 0 db test tone to set the gains LOL thats completely wrong. Fk the multi-meter, Music is too dynamic to rely on that method.

Set the volume of the head unit to 80%, sub level on the head unit all the way up. Bass and bass boost and loudness off, any eq frequencies relating to bass at flat.

play a normal song

go to the amp, bass boost off, turn the gain up until the bass stops getting louder, then back it off a bit. Viola you've set your gains properly.

Afterwards bump it and monitor amp and subwoofer temperatures, thats THE REAL WAY TO PREVENT SUBS FROM BLOWING. Some songs will need the volume turned down a bit, some will need more volume. Because the bass levels in songs have different recording levels which directly affect the pre out voltage signal which directly affects amplifier output.

So knowing that, Setting the gains at a certain set setting that you go to everytime you play music is completely stupid. Either you pigeonhole yourself out of output like you are now. In the other case, you can completely clip your subs when you set gains at a -6 or -10 db test tone and play music that has -3 or 0 db bass strength. You need to monitor EVERY song and recognize the bass strength in EVERY song and have flexibility in your head unit volume knob and sub level to compensate for tracks with weak bass recordings and have the common sense to lower the sub level or volume knob on the recordings that have stronger basslines.

again fk the multi-meter method, sh*t is outdated. Active gain setting and temperature monitoring is the best way to get the most safe output out of every song while keeping your equipment in tip top shape.

 

[Fuzion64]

I think what it comes down to is these dmm gain settings are intended to provide a relatively flat frequency response in the system. If you've come into the hobby cranking up bass settings on everything you've ever listened to - you've trained yourself to expect boom at all volumes of all music -- that's not how music is supposed to sound -- so setting it up right doesn't sound "right" to you.

I never thought about this, but you are right. I am used to hard slamming bass when playing my music whether its from a stereo setup, a boom box, a surround sound system, and so on. The flat frequency does not actually sound good to me. Which is why I asked about bass boost.

I also was unaware the bass boost only adjusts the 40hz range bass. Its strange, because without bass boost on the rear view mirror doesn't shake, which I guess isn't a big deal. Its just what I'm normally used to when listening to car audio.

let me guess. You used a 0 db test tone to set the gains LOL thats completely wrong. Fk the multi-meter, Music is too dynamic to rely on that method.

Yep i first used a 40hz 0 db test tone, then I found out when using a tone on a subwoofer amp it should be a 60hz test tone. I will set it up properly, I did it with the test tone method, because crutchfield recommended doing it this way. Then I did the multimeter method to see how much of a difference it was.

I will re-do the gain and turn the bass boost off on the amp, the lpf is set at 200hz, the isf is set at 25hz. Since the kicker comp vt's have a range of 25hz-350hz. I'm assuming the LPF needs to be set as high as possible to use the range of the sub.

On the pioneer X6800BT how do you turn off the LPF Filter, because I have heard having both the lpf and the headunit lpf on at the same time causes phase distortion within the system. Alot of stuff I have read recommends setting it on the amp, but turning it off on the headunit.

 

[n2audio 5,000+ posts]

I also was unaware the bass boost only adjusts the 40hz range bass. Its strange, because without bass boost on the rear view mirror doesn't shake, which I guess isn't a big deal. Its just what I'm normally used to when listening to car audio.

Well, w/o all that bloat at ~40 you're losing a lot of energy. That doesn't make it bad or wrong, it's just not what you're used to.

Yep i first used a 40hz 0 db test tone, then I found out when using a tone on a subwoofer amp it should be a 60hz test tone.

The frequency doesn't make much difference as long as it's somewhere in the middle of the sub's range. The only explanation I've ever come across for using 60hz is that typical DMM's are calibrated for 60hz (home electricity). Maybe so, but at that point you're really splitting hairs.

The reference level makes a LOT of difference. A -3db tone contains half the power of a 0db tone.

I've done by ear vs by dmm comparisons as well. I've come out surprisingly close.

I will re-do the gain and turn the bass boost off on the amp, the lpf is set at 200hz, the isf is set at 25hz. Since the kicker comp vt's have a range of 25hz-350hz. I'm assuming the LPF needs to be set as high as possible to use the range of the sub.

I wouldn't set the lpf that high, but it's personal choice and has a lot to do with the capability of your front stage.

ISF is enclosure dependent, but 25 is going to be reasonable regardless. If your box is sealed there's really no need for the ISF. If it's ported it's supposed to be set a few hz below the box's tuning frequency.