/diy/ - Do It Yourself

>>1822365
The amp is a Soundstream PN1.650D. I chose it because it was cheap, compact, meets its specified ratings according to amp dyno tests, and I needed a class D to minimize heat output since it had to be mounted in a less than optimal location. Capable of delivering way more power than needed, which is better than not enough.

Sub is an Alphasonik AS10DF. I’m well aware of the reputation of this brand, but I figured if the driver turns out to be a piece of shit, I could just exchange it for something better. After doing a near-field measurement, however, I’m actually quite impressed by its performance. I’ll post the response graph shortly. Also capable of getting way louder than necessary while, to my ears at least, still sounding pretty clean.

Wiring kit is a KnuKonceptz 8ga Kolossus kit. Really nice wire. It’s a PVC jacket but when you feel it in your hand you’d almost swear it was silicone or a synthetic rubber.

>>1822375
This is the result of the near-field measurement. Did it in the house using an old pc power supply to run the amp. The teal response is stock with no fill added to the box. The black response is with ~.5-1 lb of polyfill added. I wanted to see if it would make an improvement the way so many people around the internet claim it does, but I’m pretty sure the “difference” is within margin of error. I had to adjust my microphone position between the two measurements and that could easily be the source of the change.

As you can see, this sub actually extends respectably low, especially considering it’s a 10” shallow mount with an undersized enclosure.

It did actually smooth out a bit from 50-100 at higher volume levels, but I forgot to save the graph. At the loudest I was willing to run it in the middle of the night 100 was about level with 50 with a bit of a 1.5-2 dB dip in between and a sharp drop-off just above 100. Not too shabby.

>>1822385
Like it’s not even there.

I still need to figure out a method to tie the spare down. The floor pan is actually super thin everywhere other than where the original threaded insert was located. Ideally I would just weld a threaded block in the necessary location, but I unfortunately don’t know how to weld nor do I own a welder. I’ll come up with something but for now I don’t think it’s a big deal.

I was planning on taking some in-car measurements and doing some fine tuning but the shitty aftermarket Chinesium head unit I installed solely because it had Carplay doesn’t have a very good EQ/DSP section so I haven’t bothered. If this thread is still alive come Thursday or Friday I’ll take some quick measurements just to see how the sub is doing actually mounted in place, but for now I’m putting this project to rest.

Earlier some faggot on /diy/ was trying to remove the sunroof from his shitbox because "muh SPL" for his woofer install. It's a shame he wasn't around to see this. This is how car audio should be done. Clean, compact, hidden, and tuned properly.

>>1822385
Why the fuck is it so peaky?
That's awful

>>1822542
Small enclosures are very peaky. Peaking at 50hz is quite terrible but not unexpected. Arguably a custom enclosure could be made using more space around the spare tire to bolster efficiency and lower that curve, but seeing as how OP has elected to use a prefab everything I don't think it's going to happen at all.

>>1822542
Note the scaling. The peak is about 4 dB, which isn’t great, but it’s definitely not as bad as some of those cheap Wal-mart subs with reflex enclosures tuned to give like a 10 dB boost around that area. As stated before, the 50-100 area smooths out a bit at higher volume, but I forgot to save the graph to prove this.

>>1822821
I considered this idea, but it’s my wife’s car and she still wants some room down there to put things like umbrellas and ice scrapers. I’ll probably build an insulated little box for that stuff to go in just to make it less likely to get any excess moisture to the sub and amp.

I was looking at component sub drivers for about 2 weeks, plugging their small-thiele parameters into a basic calculator, and seeing which one would work best in the enclosure I was scheming up. I stumbled across this one for the dirt cheap price of $100 and decided to roll with it since the enclosure was pretty close to what I had in mind. My next choice was a JBL unit that, based on its values, should perform quite well in such a tight enclosure. If the driver in mine ever fails, I’ll probably throw that JBL in there and see what happens.

>>1822365

Did...you screw it into the gas tank?

>>1824152
No the tank is under the rear passenger seat area, just in front of the rear wheel. I checked underneath before making any holes and all the fasteners are just going into the floorpan. I don’t believe fuel tanks have been mounted behind the rear wheels since the 70’s. The Ford Maverick and Pinto were known for bursting into flames in the event if a serious rear end collision because the tanks were pretty much directly behind the rear bumper.

>>1822365
Nice job OP, you actually seem to know what you're doing.
Knu Konceptz Kolossus wire, is it white?
What software do you use for the frequency response?

>>1824335
The wire is blue for the power supply, remote enable, and speaker wire. The ground and RCA cable wire is black. The power, ground, and RCA cable wire have a Semi-translucent jacket that lets you see the conductor strands through them. I supplemented some 12ga speaker wire. The speaker wire in the kit feels really nice and I think I’ll save it for use in a future home audio project. They have more colors on their website, though I don’t think white is an option.

I used ARTA for the frequency response. I might use Room EQ Wizard for taking measurements in the car as it supports calibration profiles for 45 and 90 degree off-axis measurements which supposedly work better for pseudo-far-field measurements. The microphone is a Dayton Audio DMM-6 calibrated by Cross Spectrum Labs and the audio interface is a Behringer UM-1. A set up like this isn’t actually all that expensive. I think I spent around $200 on the hardware and the software is free for personal use. It’s amazing how much you can improve cheap speakers using simple tuning techniques and having a measuring device makes the process much smoother.