[devil84]

ok - made a decision and went with the ACM 1.300 amp - will run it in 2ohms for 300 watts RMS (i assume thats better than running at 4 ohms at 175 RMS)

what 10inch sub would you recommend to get the best out of this amp?

[choppedliver]

Originally Posted by devil84

Are the oem hk subs worth amping externally?

Thinking a 3/5 channel amp as an alternative?

As they are more of mid-woofer than a sub I’m not sure how much it would help, but I’m sure I saw someone who did it with a 2 channel amp and the harness above. That game more power to the other speakers as less speakers were being driven by the original amp. I’ll see if I can find the post.

[choppedliver]

I’m thinking this might the go. I can fold down the centre section when it’s just me in the car 99% of the time. I can also remove it if we need extra space for going in holiday.

https://audiotechdirect.com/fit-box-...for-bmw-5-g30/

I wouldn’t cut out the section behind the cup holder drop down section. Just fold the whole centre down. It looks like it will stay in place pretty well.

And this subwoofer would be a good fit in the box and would work fine with the ACM amp.

https://rockfordfosgate.com/products/details/p2d4-10/

[devil84]

Looks decent. What sub would you go for to go in there?

[choppedliver]

Originally Posted by devil84

Looks decent. What sub would you go for to go in there?

And this subwoofer would be a good fit in the box and would work fine with the ACM amp.

https://rockfordfosgate.com/products/details/p2d4-10/

[devil84]

i have decided i am going to go for a JL audio W3 (2 ohm) to pair with the amp.

this is in the optimum range for the sub and i know from YT videos, that the ACM amp dynos at 350w RMS in 2 ohm

[TacticalGunnarM550]

Originally Posted by devil84

i have decided i am going to go for a JL audio W3 (2 ohm) to pair with the amp.

this is in the optimum range for the sub and i know from YT videos, that the ACM amp dynos at 350w RMS in 2 ohm

I used to do car audio years ago, today's factory systems are what we used to dream about years ago. I'd seriously consider a powered sub tube. There are some pretty nice ones out there that will provide more than enough added sound for you.

[choppedliver]

Originally Posted by devil84

i have decided i am going to go for a JL audio W3 (2 ohm) to pair with the amp.

this is in the optimum range for the sub and i know from YT videos, that the ACM amp dynos at 350w RMS in 2 ohm

That would work well in that enclosure. My only concern is the mounting depth is 151mm and the box depth is 152mm. Very little room for error.

[choppedliver]

Originally Posted by TacticalGunnarM550

I used to do car audio years ago, today's factory systems are what we used to dream about years ago. I'd seriously consider a powered sub tube. There are some pretty nice ones out there that will provide more than enough added sound for you.

My understanding is that the trunk is sealed very well from the cabin and hence most of the base doesn’t pass through. The box above allows the centre seat to be folded down and the sub can then directly fire into the cabin. I realize you could do this with a sub tube but it’s mounting location may not be as optimal as this setup. I say may as no one knows. Given the frequencies a subwoofer operates at it may be better to have the sun further back in the boot.

[devil84]

Originally Posted by choppedliver

That would work well in that enclosure. My only concern is the mounting depth is 151mm and the box depth is 152mm. Very little room for error.

I am getting this box.

https://www.ebay.co.uk/itm/BMW-5-Series-G30-16-STEALTH-SUB-SPEAKER-ENCLOSURE-BOX-SOUND-BASS-AUDIO-10-12-/153939061565?mkcid=16&mkevt=1&_trksid=p2349624.m46 890.l6249&mkrid=710-127635-2958-0

[choppedliver]

Originally Posted by devil84

I am getting this box.

https://www.ebay.co.uk/itm/BMW-5-Ser...-127635-2958-0

An ok. I’m very interested in how much bass you get in the cabin so please keep us updated.

[devil84]

i will do.

[devil84]

Originally Posted by choppedliver

As they are more of mid-woofer than a sub I’m not sure how much it would help, but I’m sure I saw someone who did it with a 2 channel amp and the harness above. That game more power to the other speakers as less speakers were being driven by the original amp. I’ll see if I can find the post.

let me know if you do find it.

[choppedliver]

Originally Posted by devil84

let me know if you do find it.

Bah, I can’t find it now, but this link from earlier in this thread has details on how you’d wire a separate amp for the under seat speakers.

https://g05.bimmerpost.com/forums/sh...1706130&page=2

You will need a 2nd amp for the under seat speakers with a filter to send 80-250hz and a way of getting a signal to it. I think this would mean you need an L2ci so you can have a sub amp and a highs amp (underseat). That would mean a mono sub amp rather than the 1.300 and a high amp that has a mid bass filter. I’ve not done any research on this yet, but that link above mentions a JL XD300 which would be fine as the sub amp.

[devil84]

Thanks. Debating whether to go

1) lc2i and a 4 channel amp like the audison sr 4.500 and run 2 channels bridged for the sub at 440 watts. How many watts rms is safe to put thriugh the oem hk woofers. I noticed that the oem woofers are 7 ohms, will it cause any issues if I drive via a 4ohm amp at bewteen 75 to 125 Watts rms

2) lc4.800. Negates the need for the lc2i

What do you think?

[choppedliver]

Originally Posted by devil84

Thanks. Debating whether to go

1) lc2i and a 4 channel amp like the audison sr 4.500 and run 2 channels bridged for the sub at 440 watts. How many watts rms is safe to put thriugh the oem hk woofers. I noticed that the oem woofers are 7 ohms, will it cause any issues if I drive via a 4ohm amp at bewteen 75 to 125 Watts rms

2) lc4.800. Negates the need for the lc2i

What do you think?

Both setups would be fine as they have the right crossovers, channels and power. I guess the lc4.800 would be simpler to install.

Regarding the OEM woofers the 7ohm would almost certainly mean that the 4ohm rating would be reduced from say 125w@4ohm to 75w@7ohm. Without specs for the amp at 7ohm it's very hard to tell.

I would suggest wiring the OEM woofers in parallel to bring the impedance to 3.5ohm, but being left/right woofers that might do the weird things to the stereo imaging.

[Joe-BMW33]

A simple cost effective solution could be to get a powered 10" or 12" sub such as a Rockford and just T splice into the low level inputs on the rear deck speakers. I did this on my E39, battery is right there for power. Of course it is not as aesthetically pleasing as a custom built box, but for $200 ish, you are done and it's pretty powerful. Just a thought.

[choppedliver]

Originally Posted by Joe-BMW33

A simple cost effective solution could be to get a powered 10" or 12" sub such as a Rockford and just T splice into the low level inputs on the rear deck speakers. I did this on my E39, battery is right there for power. Of course it is not as aesthetically pleasing as a custom built box, but for $200 ish, you are done and it's pretty powerful. Just a thought.

I would think if there are low level inputs available at the rear then the technic pnp harness would have them and it doesn’t. Or am I missing something? There is one amp for all speakers including the rear deck so where is the low level input coming from?

[Joe-BMW33]

Originally Posted by choppedliver

I would think if there are low level inputs available at the rear then the technic pnp harness would have them and it doesn’t. Or am I missing something? There is one amp for all speakers including the rear deck so where is the low level input coming from?

I just t spliced into the rear deck speaker wiring on my E39. Works great.

[choppedliver]

Interesting.

https://f90.bimmerpost.com/forums/sh...0#post28115220

[devil84]

I am getting the lc 4.800.

Does anyone know if it's worth amping the undereat woofers?

[devil84]

Bought the stealth box, looks spot on.

looking forward to the install.

I am selling a LC2i if anyone is interested. - £80 delivered. Not needed as going down a different route.