Sub not hitting as hard as expected - Possible Lc2i tuning problem

129
1
NJ
Hey guys,

I recently wired a sub into my 2022 BMW M240i using an AudioControl LC2i Pro, Sundown Audio SFB-1000D, and a Sundown Audio SA12 in a sealed box, running 1000w @ 1 ohm. I've used the sub in my previous car and it hit really well using a Soundstream 1000w x 1 amp.

I've been trying different tuning levels on the LC2i pro but it seems like no matter what I set it to, the sub hardly moves. When it does begin to give decent output, the amps clipping light blips.

In my previous car with the soundstream amp, it hit really hard and I was expect something greater than or equal to that with the SFB amp. I tried hooking the Soundstream amp to see if maybe the SFB amp has an issue, but that amp also hits at the same lacking level as the SFB.

My assumption is the LC2i tuning is my problem. I am trying to keep the LC2i level at half or below as the max input the SFB amp can take is 5V, and the LC2i puts out 9V.

Any thoughts? Does anyone else have a similar experience when wiring a sub into a BMW? I am using the technic PNP harness to get signal.

Thanks
 
n/m... what speakers are the LOC getting signal from?
This company called Technicpnp creates harnesses that go in between the OEM amp and the OEM harness that goes into the amp, giving you a high level input for adding an amp.

PXL_20230107_171311034.jpg
 
if the signal is coming from door speakers and not a factory sub.... the lows might be getting chopped from the factory amp
 
I hooked up the bass knob which has a clip light on it and have it in hand while I drive. I am finding that I get some noticeable output with the volume up, but the clip light flickers on good bass notes.

Is it bad for the clipping light to blink on certain notes? If I set it to where it never clips, it's hardly noticeable over the OEM subs.

Thinking of getting a ported box to see if it helps.
 
I used to have that audio control loc, it only goes down to 33 hertz, I have since replaced it with a JL audio loc22, that goes down to 3 hertz, much better low end output. My vehicle emitted a low hertz noise cancelling hum, that was amplified by the loc22, so I had to have that disconnected, you may need to so as well if you go with the loc22. Good luck dude, on fixing your issue.
 
I used to have that audio control loc, it only goes down to 33 hertz, I have since replaced it with a JL audio loc22, that goes down to 3 hertz, much better low end output. My vehicle emitted a low hertz noise cancelling hum, that was amplified by the loc22, so I had to have that disconnected, you may need to so as well if you go with the loc22. Good luck dude, on fixing your issue.
I have the pro version which goes down to 20hz. I think if the clipping light blinking at times isn't bad then I can make this work with a ported box. Though, it does not feel anywhere close to the rated power of 1000w RMS/1400w max.

 
you may need to boost your bass frequencies pre-loc pro.
I had/have 1.
What i mean is eq on head unit, subwoofer level, parametric eq...whatever you can do to get more signal voltage in the low end before it even hits the loc.

If you dont get that right another box aint gonna help.
 
Couple quick notes
1. A quick flash of the clip light isn't that bad. No clipping is better but as long as it's not steady it's overall fine.
2. Bmw cars are generally built with a more solid, sound deadened cabin. So getting sound out the trunk and into the cabin is difficult. Open up the ski pass if possible.
3. A sealed box always suffers below 40hz. It's the nature of the design and is only solved with more cone area or subs specifically designed to overcome that issue. Cabin gain can often help but without knowing what the cabin gain actually is it's hard to tell what the box will do.

A ported box tuned to 32hz would be my recommendation. I would also verify that your loc is receiving full range signal. That car uses 4inch speakers in the doors iirc and will likely cut the bass significantly for those outputs.

Nice car though I was looking at a blue one a few months back. It's just not very good for audio upgrades or at least not very easy to work on.
 
You could also try bypassing the loc and wire a cell phone to your amp via rca's.

That way can rule out the sub and amp as lacking bass and confirm if your issue is with the loc... or the factory speaker signals
 
I reached out to TechnicPNP (maker of the plug n play harness) tonight asking if it's expected to output a full range signal, as the kit I bought is intended for adding a sub. They responded quickly and I learned that I plugged the harness into the wrong unit, so tomorrow I am going to make the switch and hope for the best. Odd that I still get power and music, just the incorrect level of music, likely the unamplified version. You'd think it wouldn't work at all, and that I'd break fuses, or devices entirely.

I ordered this enclosure - the price was right, Amazon prime, good reviews, and it meets the spec of my sub:

@winkychevelle Thanks, I'm very happy with the car. It is really fast and probably the best sport-luxury bang for your buck right now. And as a bonus, Toyota was involved in the motors design since it's used in the Supra, so it hopefully will have Toyota reliability

I plugged it into the unit up top when its supposed to go into the lower one (see the gray curved plug, thats where the harness should go).
PXL_20230110_033251876.jpg
 
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Problem solved! It is now loud as hell with the gain hardly up on the LC2i or amp and clipping only blips on really hard notes.

The problem was I had the plug-n-play adapter from TechnicPNP.com connected to the amp that powers the door speakers, which most likely had the bass frequencies already crossovered out. I connected it to the other one, and it's 100x better. I now regret buying the ported box, but may still use it since it's black carpeted and will match the trunk better.

I think I need to do a re-cone on the sub, I am getting a tapping sound when the sub is pushed hard. I had the same problem when it was in my BRZ on the Soundstream amp.
 
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