Replacing Rear Deck "Subwoofer"

Mephist0

Well-Known Member
103
60
Frisco, TX
Vehicle Model
2013 Civic Si
Body Style
Coupe
I just bought my '13 Si Coupe and I must say that absolutely love the car...except for one minor thing, the paper cone Honda tries to pass for a subwoofer. Honestly, I've had bargain brand computer speakers that produce more thump than this thing.

So, has anyone replaced theirs with an aftermarket unit? A Crutchfield rep told me it was 8" which is good for the type of music I usually listen to but couldn't tell me the wattage or factory amp location. I want the replacement to go in the same location to give stock appearance and don't need anything earth-shattering so keeping it in the 100-200W range is ideal.

Any suggestions?
 
There are other alternatives if you choose to go with the same size and rating speaker. just want more kick i assume? :D

Well my 1yo daughter punches harder than the factory subwoofer. :D

I found Kicker makes a great 8" subwoofer for $50 and a mono amp with speaker-level inputs for $140. That ought to give me a good boost for about $200.

Kicker 10C84 Sub
Kicker 11DX250 Mono Amp
 
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Well my 1yo daughter punches harder than the factory subwoofer. :D

I found Kicker makes a great 8" subwoofer for $50 and a mono amp with speaker-level inputs for $140. That ought to give me a good boost for about $200.

Kicker 10C84 Sub
Kicker 11DX250 Mono Amp
Keep in mind 2 things with the sub. Primary issue I remember hearing about upgrading the stock one is mounting depth being an issue. Also make sure the sub is compatible with a free air or infinite baffle setup as there is no enclosure on the rear in the trunk.
 
Yeah that sub is suitable for free-air and only has a top mount depth of a hair over 4" so it should fit. I don't think I'm going to go with that amp though because I noted that it has a built-in 80Hz low-pass filter which is too low. I just don't see the factory mids in the door and rear deck filling a gap that size in frequency. I'd be more interested in a 120-150Hz cutoff. There's another amp I found that has a variable filter that goes as high as 210Hz, so it at least gives me some adjustability.

Just saw the sticky in the Audio section on here that has the wiring schematics for the factory amp so that I can splice into the subwoofer preamps so no speaker-level inputs are needed anymore (they weren't desired anyway).

What's even better is the schematics had the subwoofer amp output wires as well. I could sever the preamp and speaker-level wires, splice them together (bypass the amp) and now the wires running to the trunk are line-level saving me from running additional speaker wire and tearing apart my interior more than I already have to.
 
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That's where it gets tricky. Tapping the pre amp harness will be difficult as the stock amp uses a balanced differential input. Most normal amps and loc's will not get a signal from before the amp. Then you have the stock amp that attenuates frequencies below 50hz to save the stock sub from blowing under high volume. I did notice this when I had my system, it was still pretty good though. Crossing over at 150hz imo is rather high. The highest I ever liked to go on a sub is 80 but as long as you know how to watch your levels its pretty much personal preference. Given a full range signal I usually cross subs over at 50hz.
 
Yeah I'm juggling around a few amps and they do have subsonic filters to negate frequencies below 30-50Hz. My reasoning to go as high as 120-150Hz was to have some frequency overlap with the mids. I figure an 8" should do well with a operating range of 30Hz-120Hz. If I were to go bigger into the 10"-12" range, I'd keep it under 100Hz. I'm trying to keep this under $200 if possible as I'm only wanting to inject a little life into an otherwise underperforming stock system.
 
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Yeah, an 8 should push those frequencies fine. With the balanced differential input you will probably have to get your amps signal from the outputs of the stock amp, and since it attenuates lower frequencies a subsonic filter shouldn't be used. In a perfect world tbh you would be better served changing the head first, bypass the amp, and then build your system out from that. The eq curves on our stock unit is hard to tune an amp to, because of the attenuations and gains, and the fact that the curve changes depending on volume. Those were my issues when running an amp and subs.
 
I disabled the SVC because it got annoying. Not looking to replace the head unit unless I can find an adapter with the carbon fiber look of the dash and iMid/BT functionality.


...well iMid isn't that necessary but it'll have to work with factory BT controls.
 
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That's where it gets tricky. Tapping the pre amp harness will be difficult as the stock amp uses a balanced differential input. Most normal amps and loc's will not get a signal from before the amp. Then you have the stock amp that attenuates frequencies below 50hz to save the stock sub from blowing under high volume. I did notice this when I had my system, it was still pretty good though. Crossing over at 150hz imo is rather high. The highest I ever liked to go on a sub is 80 but as long as you know how to watch your levels its pretty much personal preference. Given a full range signal I usually cross subs over at 50hz.

This could explain why my amp always cuts out....
 
Hi guys! First time here...2014 Si sedan(my 2nd Si)
But will just replacing the sub with a better quality one give me a little more bass?
Thanks!
 
Hi guys! First time here...2014 Si sedan(my 2nd Si)
But will just replacing the sub with a better quality one give me a little more bass?
Thanks!
Hate to revive such an old thread, but I have exactly the same question Hector has, I already searched and I only found threads of replacing the subwoofer and amp not just the subwoofer, I just want to know if I could just get a better sub and still use the factory amp?? Thanks and sorry again...
 
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