[Avetiso]

Hey guys,

I just finished replacing all the speakers in my E90 with HiFi audio.

I've only been able to find 2 references to these speakers on any BMW forums, but the Alpine S2-S40C component speakers are very easy to fit to our cars and are very affordable.

I went with this vs. other "drop-in" speakers because like many parts that are made custom-fit, I was suspicious that I was paying a huge markup for the "Made to fit your BMW" convenience and marketing, and when I saw that these were very likely to fit easily, I bought them immediately (not applicable to the Hifonics obviously, but those are still on the affordable side, relatively speaking).

This is the foam tape I used in my install steps: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Anything similar should work fine. The Alpine box also has foam tape included, but this one seemed much better suited.

Some mild customization is needed to make them fit, but it is very mild.
I'll list off what I did to get them fitted and what issues I ran into:

The cutout in the front door is a little oversized for 4" speakers, so I added some foam tape around the edge of the speaker to seal it against the door. I also added washers to actually hold the speaker in place because they don't quite reach the studs on the back of the door card. See pics.

The front tweeter is really easy. There is an adapter in the box for the Alpine tweeters. You disassemble the tweeters down to just the tiny little speaker, then lock it into the round, flat disc that comes in the box (not the plate that the tweeter originally comes attached to, this one comes in the box in its own separate little bag). Once you attach it, the tweeter can simply be popped into the receptable in the trim. It's a tad bit loose in there, though. So I added a two pieces of foam tape behind it just to keep it pressed into place.

Then just attach the crossover to the main speaker, wire up your speaker adapter and plug it in.

The rears are even easier. The rear 4" speakers fit completely drop in, you just need to remove one of the mounting tabs that interferes. You can remove the other one that is going to hit the tweeter housing, but I just opted to bend it up and avoid cutting it. Up to you.

For fitting the tweeter, I wanted to re-use the original angled housing that the OE tweeter used, so I undid the clips and cut the wires to the tweeter and pulled it out of the housing (I sacrified my tweeters, but they were already torn, and they suck anyway). I then took the Alpine tweeter, once again disassembled it to its smallest piece, and then wrapped it around in some more foam tape. This eats up the slack around the speaker, and also seals it off. It's snug enough to hold in place on its own, but I also added a little strong tape behind it just in case it ever dislodges (but I doubt it, honestly).

That's it! The speakers are $103 on Amazon for 2 midranges and 2 tweeters, all the hardware and the included crossovers.

I also found underseat subwoofer replacements on eBay that I haven't seen anyone else use. They are from Hifonics, which from what I read is a solid audio manufacturer. They were only $322 + shipping from Germany. (Actually, now that I've done some reason these look identical to the MBQuart underseat subwoofers, just a different brand name. Not sure what the difference is).

Link here: https://www.ebay.com/itm/17558930994...mis&media=COPY

I actually bought these speakers from a B-stock listing (previous return) and saved an additional $50.

Impressions of audio:

I am going to be amplifying these speakers and will post that review later, but for now these are running off the stock HiFi amp. Overall volume of the system is reduced (these are all 4ohm speakers and probably less efficient).

Underseat subwoofers add a lot of great midbass. They can reach low, but the sound drops off dramatically when they go low. This is perfect for me, since I will be adding subs. I did not want the sound of the SWS8, where the midbass leaves many people wanting more. Absolutely love what these do to the sound. I could see myself being happy with just this bass, but if you're like me and you want some bumpin low end, you'll need to add subs. Very happy with these.

As for the Alpine speakers, they sound way better, but I feel like they need more power. They obviously sound way better than the stock speakers, but I think they do edge towards sounding a little hollow on the stock power. The tweeters are much, much better, and at loud volumes they aren't super harsh like the OE ones seemed to me.

Even without an amp upgrade, I would recommend this set of speakers. The S2-S40C only came out in July of 2023, so they are fresh designs and will presumably be available for a long time.

[bmwdonut]

That's awesome to see! I'm glad to see there's people experimenting with new speakers.