Set gains, and Sub is now quiet

[mdereske 10+ year member]

Well, I picked up a Kicker zx650.4 cheap over the weekend, and hooked it up to my ID CTX65cs and a RE SR10d2. The IDs sound wonderful. I am getting a little engine noise, but working on finding that and correcting it.

The thing that gets me though, is I set the gains for the sub for a 50hz tone at 300W RMS, ie. 34.64 volts. The gians ended up being really low. Once I hooked up the sub, it was barely audible. When I had set it before with cranking the gains till distorted then backing down, it was much better. I measured it with a digital multimeter, in the bridged channels.

When I tried setting it with the sub hooked up, the multimeter jumps all over, and I cant get a constant reading.

What did I do wrong? where did I screw up?

Please help a newb out here.

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[mdereske 10+ year member]

Anyone have any advice?

 

[lyttleviet 10+ year member]

Hrmmm.....

 

[Xprime4 10+ year member]

300 watt on a 10 sealed (is it sealed ?) might be in your opinion bearely audible...

it is normal that the voltage doesn't stay constant on music coz it's dynamic. Did you change anything on the hu since you set your gain with the tone?

Clipping isn't audible on sub until it get real high... you were clipping your sub in the past but you just didn't hear it...

You could alway "cheat" a little with the gain since music isn't as loud and constant as a sine wave. Try to push your gain a little, play the sub full tilt then smell it 10 minute after that

Or get a ported box

 

[mdereske 10+ year member]

I was going to get a ported box, or make one, but can't find a plan fro a 1 cubic foot ported at 35hz. That would be the maximum efficiency of the sub. And no, didn't change anything on the HU after doing the test tone. But how do I know that the 300 watts i was seeing was at 4ohm, and not, say 2 ohms.

 

[Xprime4 10+ year member]

unhook the sub wire at the amp and check with a dmm with ohm fonction, that will tell you what ohm the amp is seeing.

2ohm/4ohm if you used a online calculator, you should have put the right number

 

[Xprime4 10+ year member]

try this: http://reaudio.com/speaker_box/LPort_Box_Calc.html

Some will say it's not the most accurate calculator, but it get the job done (might be off 1hz at tuning that's all...)

It will even give you what mdf cut you need.

 

[mdereske 10+ year member]

that is really cool. Now to go build said box, if I can find the time. Maybe sunday. I will also re-find my DMM I just bought and check the ohms I am getting. Never thought to do that. Thanks for your help.

But also, looking at that designer, its says I'll need a port 1 inch wide. Will that be enough/ok for jsut a 10" sub. I would say yes, but I am just a newbie at this stuff.

 

[BLD 25 10+ year member]

with as little as 300w, you are probably safe to set it by ear. The problem with setting gains with a DMM is that you are rarely going to see as much power as a test tone turned to the max, so really in some ways you are cheating yourself out of that power. On high power systems, it is essential, but 300w, you are probably safe to set by ear.

 

[headless 10+ year member]

What volume was your test tone? Instead of a 0db tone, use a -6db or -10db tone.

 

[liljojo4711 10+ year member]

^^^^^^^^^what will this do

 

[mdereske 10+ year member]

Yeah, I really don;t see only 300 watts being detrimental. I might just set it by ear. I can see how when you start pushing huge numbers you would need to do that.