Not loud enough.

[Grinder1989 5,000+ posts]

I hooked up my VLX 400 and my US Amps X3 crossover. Gain is set on the amp @ 1/4 because I have 8 volt pre outs. Gain on x over is set on 5 (0-20 scale) and the vari loud knob on the amp is at half. Its not nearly as loud as my 1500D. All RCA connections are correct and all are working right. I have it narrowed down to an adjustment of the gains or the vari loud knob. What should I adjust to get this thing loud and not blow my sub?

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[Grinder1989 5,000+ posts]

Bump. Some help please?

 

[squeak9798 5,000+ posts]

My first two questions are;

1) Are you giving the amp enough power from the electrical system ?

2) How did you set the gains on both the xover and amp ?

 

[Grinder1989 5,000+ posts]

1. Yes I'm not dimming.

2. Guessed, just wanted to see if it worked. My other amp comes tomorrow so I'm going to have to find a tone. Then set them tomorrow.

 

[Grinder1989 5,000+ posts]

Bump.

 

[squeak9798 5,000+ posts]

2. Guessed, just wanted to see if it worked. My other amp comes tomorrow so I'm going to have to find a tone. Then set them tomorrow.

My guess would be that it was related to the gain structure.

When you set them, you want to have all of the "gain" in the system as early as possible.

So set the headunit to it's maximum unclipped output. Then with the volume at that level, set the output of the xover to it's maximum unclipped output. Then set the gain as normal.

 

[Grinder1989 5,000+ posts]

My guess would be that it was related to the gain structure.
When you set them, you want to have all of the "gain" in the system as early as possible.

So set the headunit to it's maximum unclipped output. Then with the volume at that level, set the output of the xover to it's maximum unclipped output. Then set the gain as normal.

Maximum H/U volume is 75 out of 80 (dead head). The gain on the crossover is at 5 out of 20 so I'm going to try about 15. Then I'll try setting the gain. Thanks Squeak, I'll let you know how it goes.//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Grinder1989 5,000+ posts]

I increased crossover gain to 15 out of 20. I'm not sure if that is safe though and I have no way of telling if I'm clipping. What do you think Squeak?

 

[squeak9798 5,000+ posts]

Tough to say, I'm not familiar enough with the unit.

If the crossover's "gain" is simply an attenuator (i.e. setting it to 20 = 0db, and turning it lower than 20 simply attenuates the signal by some level) then it should be safe all the way up.

But again I can't say for sure how it actually acts as I'm not familiar with the unit. My suggestion would be to 1) check with US Amps, or 2) grab a DMM and compare the voltage input to the voltage output.

 

[Grinder1989 5,000+ posts]

Tough to say, I'm not familiar enough with the unit.
If the crossover's "gain" is simply an attenuator (i.e. setting it to 20 = 0db, and turning it lower than 20 simply attenuates the signal by some level) then it should be safe all the way up.

But again I can't say for sure how it actually acts as I'm not familiar with the unit. My suggestion would be to 1) check with US Amps, or 2) grab a DMM and compare the voltage input to the voltage output.

Oh, well your help is greatly appreciated. I have found out that the adjustment is really 0-9 volts. Not sure why there is 0-20, but I have it in a 2001 owners manual. So I'm guessing with 8 volt pre-outs, I should be in the 15 area correct? I'll PM this thread to Flakko, he may have more experience with it. I should check it with a DMM to be safe anyway. But thanks Squeak.

Also I should say that @ 0, the speaker will not move even with the gain turned up on the amp.

 

[thegreatestpenn 5,000+ posts]

that's cause the signal's not strong enough for the amp to "amplify" it. I've had this happen with 2V preouts. I'd have to turn the gain on the amp to about 1/4 before it even produced sound. Just look at the gains setting tutorials by doing a search and follow what was said about maxing out all gains besides the amp. For example, when setting the gains for my system, I turned My HU's subwoofer setting to its highest, +8. Then I turned my linedriver all the way up to 8V. now I barely have to turn the gain up on the amp to get full output.

 

[Grinder1989 5,000+ posts]

that's cause the signal's not strong enough for the amp to "amplify" it. I've had this happen with 2V preouts. I'd have to turn the gain on the amp to about 1/4 before it even produced sound. Just look at the gains setting tutorials by doing a search and follow what was said about maxing out all gains besides the amp. For example, when setting the gains for my system, I turned My HU's subwoofer setting to its highest, +8. Then I turned my linedriver all the way up to 8V. now I barely have to turn the gain up on the amp to get full output.

Your saying that I need to turn the gain up on the crossover because the signal going to the amp isn't strong enough right?

 

[IamDeMan 5,000+ posts]

Everything is guesswork until you use a DMM to properly set ALL levels. PERIOD

You may have used only 1/4 of gain on the 1500D, but that doesn't mean you will need the same gain setting for the VLX400.

BTW that VLX will easily consume twice the electrical current of your 1500D, so I hope the electrical is up to snuff. That is one hungry amplifier.

 

[Grinder1989 5,000+ posts]

I know that. I'm going to keep the gain low on the amp itself for that reason. Bump.

 

[chillin 10+ year member]

I know that. I'm going to keep the gain low on the amp itself for that reason. Bump.

keeping the amp gain low doesnt matter if everything else is high. If the sub out level is high and your gain on the amp soesnt need to be as high for the same output, your still drawing the same current. If fthe amp is creating the power, it is drawing the power, no matter where the gain is.