Xover not working on new amp

[mrbojang 8]

Hi,

I just received a new sundown sae-1200dv2..Hooked it up, runs fine however the crossover is not working properly. My current setup consists of the stock head unit ('06 tahoe) with a Scosche LOC-80 line out converter with the gains set around 85%. I was running a directed 1200/5 before and the setup worked fine.

However now using the sae when I turn the LPF all the way down I still hear vocals coming out of my subs. I was told this is because my old amp used a 24dB slope, and the sundown amp uses 12dB.

I have no idea where to go from here. Any suggestions please?

[Sir-Lancelot 216]

What do you have the LPF set at?

[mrbojang 8]

What do you have the LPF set at?

Sorry forgot to include that. I had it set to 100hz originally then tried it all the way down to 50hz and still hear vocals coming out of the subs. A friend suggested I turn the gain down on the line output converters, not sure if that would help?

Thanks.

[lithium 358]

even if they are 12 db slopes you should not be able to hear vocals at all.... something is wrong... do you have the rca's plugged in to the "inputs" and not outputs @ the amp

[mrbojang 8]

even if they are 12 db slopes you should not be able to hear vocals at all.... something is wrong... do you have the rca's plugged in to the "inputs" and not outputs @ the amp

Wow that would be ridiculous. I'm checking now. I emailed jacob at sundown and he recommended get an external crossover unit. He was extremely helpful. I'll get back to you in a minute and let you know if I actually hooked it up wrong..

[mrbojang 8]

even if they are 12 db slopes you should not be able to hear vocals at all.... something is wrong... do you have the rca's plugged in to the "inputs" and not outputs @ the amp

It is wired into the inputs. I didn't think I was that foolish. I even checked the sub's wiring and they're wired for 1ohm. They're two 4dvc subs. The output is WEAK as hell. I just put in a new battery today also...

I think the amp is defective. :\

[cheese20323 13]

It can be defective. Your gain is probably low and have you checked how they are wire like if each has positive on positive not positive to ground you know. That happened to me once and fixed it and it sounded normal.

[mrbojang 8]

It can be defective. Your gain is probably low and have you checked how they are wire like if each has positive on positive not positive to ground you know. That happened to me once and fixed it and it sounded normal.

The subs are wired in parallel. Two 4dvc subs. They're wired positive to amp on one coil, positive to other coil. Negative to other coil and negative to amp. It was working fine with my old amplifier.

So negative to negative to amp and positive to positive to amp.

[mrbojang 8]

It can be defective. Your gain is probably low and have you checked how they are wire like if each has positive on positive not positive to ground you know. That happened to me once and fixed it and it sounded normal.

I also had gain up 100% on headunit and it barely moved. Same with setting it high on the amp. Nothing impressive.

[Impious 1,476]

Grab a DMM and 100hz test tone. Unplug the subwoofer, set the DMM to Vac and put it on the speaker outputs of the amplifier. With the test tone playing, turn the lowpass crossover knob from minimum to maximum (or vice-versa) and see if the voltage output from the amplifier changes. If not, then it's fairly conclusive that the amplifier is indeed defective.

[mrbojang 8]

Grab a DMM and 100hz test tone. Unplug the subwoofer, set the DMM to Vac and put it on the speaker outputs of the amplifier. With the test tone playing, turn the lowpass crossover knob from minimum to maximum (or vice-versa) and see if the voltage output from the amplifier changes. If not, then it's fairly conclusive that the amplifier is indeed defective.

Jacob from sundown is having me test the RCA lead voltage and the voltage coming out of the amp speaker terminals. I will try out your method tomorrow. Thanks for the help.

[mrbojang 8]

So I made the mistake of going to a local car audio shop and seeing if they'd hook up the amp to another source...

1st they took my truck without fully talking to me and letting me explain what's going on, came back 10 minutes later "uh it works, you need to set the xover! you don't have any mids?" i had my gain set all the way to the rear to test the subs, and they were playing some FM crap that didn't show vocals in the subs for some reason.

I explained I tried setting the xover all the way down and still got vocals coming out of the subs. I put in a cd and showed them. They take it for another 5 minutes and say I need a new head unit or external crossover unit (which jacob said) or a new amp, and they said the amp doesn't have LPF or HPF and I need both for the subs.

The amp has a x-over (LPF, right?). My old one was only using LPF and it handled the signal fine...

I took out the amp and hooked up my old one for now. I think my best bet is just to get a head unit or a high end LOC like a JL cleansweep and a external EQ if I need to. I'd rather do the latter as it's cheaper than getting a new HU, GM harness, steering wheel harness, and a dash kit.

I originally was thinking I could take the sub output from my old amp which i was going to use for my mids and use that to feed into the new amp, however I don't think it outputs a equalized signal?

If the amp still isn't performing properly I guess it's borked and I'll send it in?

This kind of sucks, I was waiting acouple weeks to be able to get the amp and was pretty excited.

Edited May 1, 2010 by Mr. Bojangles

[Impious 1,476]

Did you do what I asked? It'll take all of 5 minutes and give you a quick idea if the crossover on the amp is functioning or not.

Don't buy anything until you can verify that the amplifier is functioning properly.

[mrbojang 8]

Did you do what I asked? It'll take all of 5 minutes and give you a quick idea if the crossover on the amp is functioning or not.

Don't buy anything until you can verify that the amplifier is functioning properly.

I will test out your method shortly. Thanks for the help.

[mrbojang 8]

Did you do what I asked? It'll take all of 5 minutes and give you a quick idea if the crossover on the amp is functioning or not.

Don't buy anything until you can verify that the amplifier is functioning properly.

Ok, somewhat stupid question -

I recrimped my power and ground cable with spade\fork terminals, they're 4gauge. Could I just put them into the amp's power "holes" and screw them in or do I need to cut them again?

[Impious 1,476]

I wouldn't leave them like that long term, but just for quick testing purposes if the spade connectors fit into the openings you will be fine.

[mrbojang 8]

Did you do what I asked? It'll take all of 5 minutes and give you a quick idea if the crossover on the amp is functioning or not.

Don't buy anything until you can verify that the amplifier is functioning properly.

Ok!

I set the head unit bass gain to 50%, the channels to 100% rear (those are the outputs to the amp) and played a 100hz test tone. (sine wave)

Readings:

Xover on center: 10.1

Xover 100%: 22.7

Xover 0%: 3.7

So since the voltage is changing, it's a problem with my input signal?

Edited May 1, 2010 by Mr. Bojangles

[KU40 173]

What head unit do you have? Is there a crossover on the head unit for the rear speakers? If so, it's likely a highpass, and it may be cutting off all bass frequencies down the RCAs to your amp. If that happens you'll be fighting to get a bass signal and have to crank the gains, which will make the voices more prevalent.

[mrbojang 8]

What head unit do you have? Is there a crossover on the head unit for the rear speakers? If so, it's likely a highpass, and it may be cutting off all bass frequencies down the RCAs to your amp. If that happens you'll be fighting to get a bass signal and have to crank the gains, which will make the voices more prevalent.

I'm using the stock head unit with a line out converter, no x-over settings on the head unit. I'm using the rear channels with no speakers connected. I get bass (granted the gain is near 90% on my other amp - a directed 1200/5, old amp). I don't quite understand why the x-over on that amp can handle it but the sae-1200dv2 can't. I'm going to get an aftermarket head unit soon and run the sae-1200dv2 then, and eventually two of them. Have a big shopping list but a head unit is obviously priority..

[Impious 1,476]

Did you do what I asked? It'll take all of 5 minutes and give you a quick idea if the crossover on the amp is functioning or not.

Don't buy anything until you can verify that the amplifier is functioning properly.

Ok!

I set the head unit bass gain to 50%, the channels to 100% rear (those are the outputs to the amp) and played a 100hz test tone. (sine wave)

Readings:

Xover on center: 10.1

Xover 100%: 22.7

Xover 0%: 3.7

So since the voltage is changing, it's a problem with my input signal?

Looks like the crossover is functioning just fine. Based on those voltages, the signal was down -15db @ 100hz when the crossover was set to 50hz, which is -3db more than expected (12db/oct slope) but could be due to inaccuracies in the crossovers (the pot style crossovers on amplifiers are rarely 100% accurate in range from the tests I've seen).

So just to clarify, the two problems you are experiencing is weak output from the amplifier and you feel you are getting too much of the higher range of sound out of the subwoofer?

[mrbojang 8]

Did you do what I asked? It'll take all of 5 minutes and give you a quick idea if the crossover on the amp is functioning or not.

Don't buy anything until you can verify that the amplifier is functioning properly.

Ok!

I set the head unit bass gain to 50%, the channels to 100% rear (those are the outputs to the amp) and played a 100hz test tone. (sine wave)

Readings:

Xover on center: 10.1

Xover 100%: 22.7

Xover 0%: 3.7

So since the voltage is changing, it's a problem with my input signal?

Looks like the crossover is functioning just fine. Based on those voltages, the signal was down -15db @ 100hz when the crossover was set to 50hz, which is -3db more than expected (12db/oct slope) but could be due to inaccuracies in the crossovers (the pot style crossovers on amplifiers are rarely 100% accurate in range from the tests I've seen).

So just to clarify, the two problems you are experiencing is weak output from the amplifier and you feel you are getting too much of the higher range of sound out of the subwoofer?

Correct. I had the x-over down to 50hz and still could hear vocals. Power output may be subpar, I didn't really bump it for long since i wasn't sure what was being fed through the subs and didn't want to damage them.

When I did have it up high it seemed as if my old amp which is putting out roughly 600watts less powered the subs better. The subs are under powered by 200 watts each.

I was thinking I could possibly try turning the gain down on the LOC? I don't know how that would affect the crossover and what it does to the input signal.

[emperorjj1 2]

double check phase on both the subs and the input for the rcas.... unplug one of the rcas and see what the volume difference is. if the volume goes down by ~half then its correct if it goes up by double then its out of phase. do the same with the subwoofers unplug one of the 2 ect

[KU40 173]

Did you do what I asked? It'll take all of 5 minutes and give you a quick idea if the crossover on the amp is functioning or not.

Don't buy anything until you can verify that the amplifier is functioning properly.

Ok!

I set the head unit bass gain to 50%, the channels to 100% rear (those are the outputs to the amp) and played a 100hz test tone. (sine wave)

Readings:

Xover on center: 10.1

Xover 100%: 22.7

Xover 0%: 3.7

So since the voltage is changing, it's a problem with my input signal?

Looks like the crossover is functioning just fine. Based on those voltages, the signal was down -15db @ 100hz when the crossover was set to 50hz, which is -3db more than expected (12db/oct slope) but could be due to inaccuracies in the crossovers (the pot style crossovers on amplifiers are rarely 100% accurate in range from the tests I've seen).

So just to clarify, the two problems you are experiencing is weak output from the amplifier and you feel you are getting too much of the higher range of sound out of the subwoofer?

Correct. I had the x-over down to 50hz and still could hear vocals. Power output may be subpar, I didn't really bump it for long since i wasn't sure what was being fed through the subs and didn't want to damage them.

When I did have it up high it seemed as if my old amp which is putting out roughly 600watts less powered the subs better. The subs are under powered by 200 watts each.

I was thinking I could possibly try turning the gain down on the LOC? I don't know how that would affect the crossover and what it does to the input signal.

You won't damage the subs playing higher frequencies or vocals through them.