Setting Gains with LC2i! Still unresolved :(

[zoltman1991]

Ok. I have tried many times. I got it to where I want to be, but the voltage was reading higher than my target. I want to protect my speakers and ensure longevity.

I have a JD1000.1 with a 15" CVX at 2ohms, with an LC2i.

This is what I have done:
-50hz test tone 75% to set LC2i just before maximized light turns on.
-Acubess threshold down/Acubass level down (I tested it, no roll off. Consistent increase)
-Then I check voltage at amp.
-WITH GAIN all the way down, I am reading about 56.
-My target should be about 44.7 (1000x2=2000. sqrt(2000) = 44.7.
-Amp input is set to low input.

BUT THE CLIPPING light on the amp triggers WELL above the 56 number - probably around 76.

What is going on? If I truly set it to where the voltage is at 44.7, this speaker is well underpowered. I upgrade from 400w into a 12", and it was less than that.
What am I missing here?

Can I trust the clipping light? Can I run at a voltage higher than 44.7 if clipping light doesn't activate?

Click to read more...

 

[zoltman1991]

@Doxquzme I'm looking at you my man. I'm still not able to figure it out

 

[dragon.breath 10+ year member]

Sometimes the only thing you can do is go old school and set it without using any tools. Connect the sub to the amp. Find either an old school bass cd or something rebassed and turn up the gain until the amplifier clip light starts flickering at the start of the beat.

 

[zoltman1991]

Sometimes the only thing you can do is go old school and set it without using any tools. Connect the sub to the amp. Find either an old school bass cd or something rebassed and turn up the gain until the amplifier clip light starts flickering at the start of the beat.

I mean this light doesn't start even think about flickering until voltage is 70s.
Is this safe for my subwoofer? Because I can blast this thing and get the bass I want, but voltage readings will be much higher.

 

[Doxquzme Premium Member]

I always set each step at slightly below clipping that way you know they are all pretty much at their safe max output. Then I attenuate by ear with the amp gains. The numbers on the HU are just for reference. You ,ight want to take a look at this for some tips.

https://www.stevemeadedesigns.com/board/topic/166082-gains-for-dummies/

 

[Jimi77 Premium Member]

Set gains by ear with test tone. If you have a ported enclosure, I'd use a test tone close to but slightly above tuning. Since you're using accubass (IIRC), I'd suggest a test tone below 40hz. Clipping is pretty audible with a test tone. Start with the HU volume and find clipping - some HUs don't clip at all if you don't use bass boost, loudness, etc. Then dial up the output(s) on the processor until you clip. Last but not least adjust the gain on the amp.

 

[zoltman1991]

Set gains by ear with test tone. If you have a ported enclosure, I'd use a test tone close to but slightly above tuning. Since you're using accubass (IIRC), I'd suggest a test tone below 40hz. Clipping is pretty audible with a test tone. Start with the HU volume and find clipping - some HUs don't clip at all if you don't use bass boost, loudness, etc. Then dial up the output(s) on the processor until you clip. Last but not least adjust the gain on the amp.

So what I'm gaining is... F*** the voltage readings. Set by clipping - by ear or oscilloscope.

Am I setting full 75% blast with test tone?? Sub plugged in, correct. That's a lot of bass to experience.

 

[Jimi77 Premium Member]

So what I'm gaining is... F*** the voltage readings. Set by clipping - by ear or oscilloscope.

Am I setting full 75% blast with test tone?? Sub plugged in, correct. That's a lot of bass to experience.

If it's a DVC sub, then do it with the sub wired in series for the first 2 steps and then wire it correctly when you set the gains on the amp. You can take the sub out of the car to reduce the SPL you're exposed to. At least by ear or o-scope, you'll know if you're clipping or not.

 

[zoltman1991]

If it's a DVC sub, then do it with the sub wired in series for the first 2 steps and then wire it correctly when you set the gains on the amp. You can take the sub out of the car to reduce the SPL you're exposed to. At least by ear or o-scope, you'll know if you're clipping or not.

So to determine clipping from HU, wire sub in series? Is this strictly to increase resistance so it's not as loud?

Also when determining if there is clipping from amp to sub while adjusting amp gain... silly question.. but what am I listening for. I've read many places a hum into a buzz. Will it be a very apparent and obvious transition?

 

[Jimi77 Premium Member]

So to determine clipping from HU, wire sub in series? Is this strictly to increase resistance so it's not as loud?

Also when determining if there is clipping from amp to sub while adjusting amp gain... silly question.. but what am I listening for. I've read many places a hum into a buzz. Will it be a very apparent and obvious transition?

Wire the sub series to increase resistance and reduce SPL. How the sub is wired doesn't matter when you're making adjustments at the HU and processor level.

Hum to a buzz is a good description. It sounds like the frequency starts to shift up, sounds kinda edgy and not as clean. Once you hear the clipping dial the gain back a little (1-3db). Or you can let the amp clip a little. For a daily driver, even 3db of clipping is pretty safe.

 

[zoltman1991]

Wire the sub series to increase resistance and reduce SPL. How the sub is wired doesn't matter when you're making adjustments at the HU and processor level.

Hum to a buzz is a good description. It sounds like the frequency starts to shift up, sounds kinda edgy and not as clean. Once you hear the clipping dial the gain back a little (1-3db). Or you can let the amp clip a little. For a daily driver, even 3db of clipping is pretty safe.

You're the absolute man. Everyone on this forum has been an incredible help the last week as I navigate my new system. I think the LC2i addition has been throwing me off balance. I used to have after market stereo, so never needed this.

Also quick question.
If my voltage is measuring 56 with gain all the way down, can I assume the output voltage from LC2i is high? Should I adjust amps input to high level?

-to confirm this - do I check ACV multimeter from RCA cable ends from LC2i? if higher than 2v (amp's low input is up to 2v) do I turn on high level input on amp?

 

[Jimi77 Premium Member]

You're the absolute man. Everyone on this forum has been an incredible help the last week as I navigate my new system. I think the LC2i addition has been throwing me off balance. I used to have after market stereo, so never needed this.

Also quick question.
If my voltage is measuring 56 with gain all the way down, can I assume the output voltage from LC2i is high? Should I adjust amps input to high level?

-to confirm this - do I check ACV multimeter from RCA cable ends from LC2i? if higher than 2v (amp's low input is up to 2v) do I turn on high level input on amp?

You should probably use the high level input setting on the amp; the LC2i has up to 9.5v preamp output. Yes you can measure for ACV at the RCA cables from the LC2i.

 

[zoltman1991]

You should probably use the high level input setting on the amp; the LC2i has up to 9.5v preamp output. Yes you can measure for ACV at the RCA cables from the LC2i.

Done and Done! It was consistently reading about 4.
Changed it to high input.
Adjusted gain to hit 44ish.
Waiting on oscilloscope from Amazon to finer tune to hit my my sub-distortion level.

As of now, it sounds soft of course. I have high hopes, however.

Should I adjust as we discussed? I was told I can set the acubass threshold hold up and then turn acubass dial simply to add more bass to the signals. Should I veer away from this and do what we discussed with ear/oscilloscope?

 

[Jimi77 Premium Member]

Done and Done! It was consistently reading about 4.
Changed it to high input.
Adjusted gain to hit 44ish.
Waiting on oscilloscope from Amazon to finer tune to hit my my sub-distortion level.

As of now, it sounds soft of course. I have high hopes, however.

Should I adjust as we discussed? I was told I can set the acubass threshold hold up and then turn acubass dial simply to add more bass to the signals. Should I veer away from this and do what we discussed with ear/oscilloscope?

I'd dial in the amount of accubass you want at low volume and then set the gain the on the amp. I wouldn't use the accubass like an additional bass boost or gain. How does Audio Control recommend you set the accubass feature?

I'd go ahead and set the gain by ear as I described.

 

[Mitchell Fosgate III]

Ok. I have tried many times. I got it to where I want to be, but the voltage was reading higher than my target. I want to protect my speakers and ensure longevity.

I have a JD1000.1 with a 15" CVX at 2ohms, with an LC2i.

This is what I have done:
-50hz test tone 75% to set LC2i just before maximized light turns on.
-Acubess threshold down/Acubass level down (I tested it, no roll off. Consistent increase)
-Then I check voltage at amp.
-WITH GAIN all the way down, I am reading about 56.
-My target should be about 44.7 (1000x2=2000. sqrt(2000) = 44.7.
-Amp input is set to low input.

BUT THE CLIPPING light on the amp triggers WELL above the 56 number - probably around 76.

What is going on? If I truly set it to where the voltage is at 44.7, this speaker is well underpowered. I upgrade from 400w into a 12", and it was less than that.
What am I missing here?

Can I trust the clipping light? Can I run at a voltage higher than 44.7 if clipping light doesn't activate?

Wow. You must be a rich man. At 1 ohms, didn't it burn on first trial? Trying to get it down to low hz. Like flames shooting out of the connections from the amplifiers.