[boostd92]

I'm about to do a complete sound system re-vamp on my 2009 335i sedan with the HiFi system. The plan was to do the Bavsound complete interior kit with underseat subs.

From what research I've done, it sounds like the Ghost subwoofers from Bavsound can handle a lot more than the factory HiFi amp puts out and significant bass/sound output can be had using an additional amp.

I was looking at the Soundstream ST3.1000D but curious if the audiophiles in here that know about impedance and power, etc could chime in. This is a 3 channel amp and runs both speaker outputs at 2ohm stereo (which I believe is what the factory subs run at), and has a separate D channel to add a trunk subwoofer (eventually). Also has line-level inputs so no LOC required. Here is the model I'm looking at:

https://soundstream.com/product/st3-1000d/

My question is, are there under seat subs signal wires going from the headunit to the amp or does the factory amp only take the front/rear channels and outputs it's own filtered sub channel to the underseat subs? Trying to figure out where to cut in to get speaker level (high) wires to input into the Soundstream amp.

Thanks!

[Ali-E90]

Tap the signal from the under seat subs, if you tap from the others likely you won’t have any bass.
Look into the technic pnp harness, may simplify things.

Don’t forget to set appropriate HPF on your under seat woofers, this will allow them to better handle the power from the larger amp, and also work better when you add the dedicated sub on the 3rd channel.

[ctuna]

there are better speakers for the money than bavsound .
The amplifer as a whole is the weakest part of the Hi Fi system
but the speakers are not that much further behind.

6 channel amp with a Technic Harness or
6 channel DSP/Amp with a Technic Harness.

BMW stereo types
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447

Match and Helix = Audio tech Fisher they are two different lines withing the brand.
http://www.e90post.com/forums/attach...1&d=1209780865
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://technicpnp.com/menuDiagrams/d...e90_92_93.html
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...3&d=1169133185
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/showthread.php?t=641323
http://www.e90post.com/forums/attach...4&d=1278871872
http://www.e90post.com/forums/showthread.php?t=343673
https://www.bimmerfest.com/threads/e...n-752.1275694/

base system wiring pre/post 3/09
https://www.google.com/url?sa=t&rct=...tDpLJPcGkw_ui_
Base System Guide
http://www.e90post.com/forums/attach...5&d=1493273253

There are many other plug and play speakers besides Bavsound.
Bavsound uses a rebranded Audiotech Fisher Amp/Dsp themselves.
I believe it is the BMW7 .

[boostd92]

Originally Posted by Ali-E90

Tap the signal from the under seat subs, if you tap from the others likely you won’t have any bass.
Look into the technic pnp harness, may simplify things.

Thanks! I sent technic a message about my plans.

So are you saying that the subwoofer outputs at the amp connection in the trunk do not go directly to the underseat subs? Is that why I can't tap them there (where the new amp will be) vs. running wires backwards from the front seats?

[ctuna]

There is a wiring diagram in the links can you read it ?
There is also a sticky that says Wiring diagram for the members
at the top of the forum page.
The amp is fed FR FL RR and RL signals from the head unit
at 5 volts differential . (For e9x with Hi Fi system)
I can't teach everybody basic electronics or car stereo theory.

4 channels from the head unit to the amp
6 channels from the amp to the speakers . 4 to the doors 2 to the floors
If you wanted to add another amp it would have to be on the output
of the existing amp though I think this is a mistake. ,because the Hi Fi amp
is crap on all channels and speakers.

[boostd92]

Thank you, the sticky is very helpful. I misread Ali-E90's reply above as "tap the signal at the underseat subs" to mean, physically tap the wires under the seat.

I see now that he just meant tap those speakers output wires (wherever), and not any of the other speaker wires (like doors or parcel shelf).

[ctuna]

He was probably trying to run a true sub amp to a trunk sub.

[Ali-E90]

Originally Posted by ctuna

He was probably trying to run a true sub amp to a trunk sub.

He inquired about using a 3-ch amp, and I thought he meant two channels for the seat woofers and the mono 3rd channel on a sub. In that scenario, I think signal from the under seat is all he’d need… with a HPF on the mid bass and LPF on sub channel (somewhere between 60-80hz for both).

My response was for that use case. Maybe I misinterpreted.

[boostd92]

Thank you for the replies. After getting mostly into my 12 hour break-in on the Bavsound full speaker/sub package (no amp), I've found that the Ghost subs are definitely more accurate than the OEM ones, but the OEM ones might have hit lower notes. Either way, neither sub will put out the lows I want for hip-hop stuff, but I think the factory amp powers the Ghost subs just fine for the mid-bass stuff.

I'm going to cheap out and go simple, since I like being able to take the sub in and out of the trunk when needed and am going with an all-in-one Rockford P300 12, amplified unit. This one here:
https://www.amazon.com/Rockford-Fosg...4-dc28e6d374b3

My question is, since this system has high/speaker level inputs, can I tap the underseat subwoofer output wires from the HiFi amp and feed them directly to this unit? Or is a LOC absolutely necessary?

Thanks!