Alpine R2-W12-D2- Frequency Issue

[BA55 AMG]

Hi Everyone, i am new to the forum. I have a slight issue i was hoping to get some advice on- I have done some freq sweeps and my new sub- Alpine R2-W12-D2 /// is running around 45 Hz. Factory rating is 24 to 200 hz. I want to get it around 30 or even lower if i can.

My install is in a 2017 KIA Sportage GT Line S- Factory everything- JBL 8 speaker system (8" sub now disconnected) and factory head unit. Then i added in- the 12" Alpine sub in a ported box (volume is within factory range), Audio Control LC2i to get good signal quality and the amp is Pioneer GMD 8701- 800 RMS. It’s all wired to 800 RMS @ 1 ohm.

The sub is super loud and hits hard BUT 45 hz is far too high!! I dont think box tuning will make a huge difference that i require, do i go for the LC2i Pro and will that do the trick? Or is this simply a Head Unit issue and until thats replaced nothing much is going to change here? Thanks for reading........

 

[Philbo King]

You probably need a bigger car to mount the speaker into. Just a guess.

 

[Head_Unit]

Well. Where/how is the sub mounted in the Sportage? What's the size of the box? Ported or sealed? A PICTURE is worth 1000 words Confucius said. How are you measuring it only goes down to 45 Hz (I think that is what you mean by "is running around???)? A microphone? Your ears? A phone? I can tell you as a loudspeaker engineer that box tuning absolutely makes a tremendous difference to the response. The head unit I worked on a lot of OEM projects, all the electronics could do 20 Hz. The Audio Control LC2i is the AccuBASS turned OFF? Turn it off to try and establish actual performance. Ah what was powering the factory sub? There must be a system amp which maybe has some kind of filtering (??)
- If you move the sub to different spots do you have the same problem?

As a separate experiment, never mind amp specs, rewire to 4 ohms and see if you get just as much peak volume out of the sub (but with less current drawn from the battery and less waste heat).