Spent the weekend installing my new sub setup and getting everything dialled in properly.
I was previously running an MTX Thunder 8" sub which, to give it credit, sounded awesome. Being an 8", though, it was more punchy and I wanted something with a bit more depth, so I decided to move up to a 10" and go for more of an OEM+ look.
As you can see, I had previously made a custom false floor section to house the MTX and stop it moving around.

I made a little false wall for the amp using some MDF offcuts I had lying around. It gives me somewhere solid to mount the amp, hides all the wiring and I've raised it slightly to allow for some extra ventilation behind it.
Of course, it wouldn't be one of my installs without something annoying going wrong!

I didn't realise I'd put the ground cable through the wrong hole until I'd already cable-tied the corrugated sleeve into place. I'll sort that at some point because I already know it's going to bug me every time I look at it!
I also learnt something new while researching the install the gain control on an amplifier isn't simply a volume or "more bass" control.
The gain is basically used to match the amplifier to the signal coming from the head unit. Rather than just turning it up until it sounds loud enough, you can work out the voltage the amp needs to produce the desired power and then use a multimeter to set the gain accurately.
In my case, I'm running a HELIX M ONE X amplifier with my HELIX 10" subwoofer wired to 4 ohms. The amp can produce 400W at 4 ohms, while the sub is rated at 300W RMS.
To work out a sensible target voltage for the sub, you use:
300 watts × 4 ohms = 1,200Then you take the square root of 1,200, which gives 34.6 volts.
So I set the amplifier's gain to around 34–35 volts using a multimeter.
The amp is capable of 400W at 4 ohms, which would be 40 volts, but because the sub is rated at 300W RMS, there's no real reason to set the gain to allow the full 400W. Setting it around 34.6V keeps the target much closer to the sub's rated power.
It's a much better way of setting the gain than simply turning it up until it sounds loud enough. The gain isn't a bass boost or volume control it's there to match the amplifier to the input signal and set an appropriate maximum output.
Overall, I'm really happy with how it's turned out. It's a pretty big upgrade over the MTX setup and I much prefer the more subtle OEM+ look.
The extra size of the 10" sub gives me the deeper bass I was looking for without turning the boot into a complete boy-racer setup.











