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      11-17-2019, 08:37 PM   #1
Lozza47
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Hi Fi Under seat sub upgrade

Hi all,

Does any one have any recommendations for the best direct fit under seat sub upgrade over Hi Fi sound system in m235i?

A lot of threads are based on improvements over HK system.

I won't be changing the amp either.

Alternatively, if you could only do one - would changing out the speakers or changing out the amp for something like bimmer tech's harness the best audio performance improvement?

I find the low 20-60hz area on the m235i to be no existent.
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      11-17-2019, 09:39 PM   #2
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Definitely the Bavsound Ghosts, they're '10 dB+ louder from 20Hz to 60Hz vs factory woofers'
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      11-18-2019, 10:07 AM   #3
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Lozza47,

I just upgraded my M240i with the HiFi system by only changing the speakers. A local car audio shop installed the Bimmer Tech Alpha One speakers (woofers, tweeters and midrange). They also swapped out the blank sails with the HK ones to hold the tweeter. The changes have been dramatic and everything sounds great now. I don't feel there's any need to update the amp to great sound if you switch out the speakers.
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      11-22-2019, 01:14 PM   #4
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The Earthquake SVS were a good improvement on my car with HIFI. Cost less than the Ghosts.
An amp with some DSP capability should help a lot and will be my next move.

20 to 60 hz IS non existent in the HF because they put in lower quality subs and EQ it out in the crappy amp. The HK is only slightly improved.
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      11-22-2019, 01:27 PM   #5
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If you want best low-cost, low-hassle option get this for your trunk along with the remote. See TechnicPNP for the add an amp harness.

https://www.crutchfield.com/p_136933...v3.html?tp=114
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      11-24-2019, 06:43 AM   #6
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Quote:
Originally Posted by BEM-S4 View Post
If you want best low-cost, low-hassle option get this for your trunk along with the remote. See TechnicPNP for the add an amp harness.

https://www.crutchfield.com/p_136933...v3.html?tp=114
Thanks for the info guys.
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      11-24-2019, 05:30 PM   #7
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Quote:
Originally Posted by Lozza47 View Post
Hi all,

Does any one have any recommendations for the best direct fit under seat sub upgrade over Hi Fi sound system in m235i?

A lot of threads are based on improvements over HK system.

I won't be changing the amp either.

Alternatively, if you could only do one - would changing out the speakers or changing out the amp for something like bimmer tech's harness the best audio performance improvement?

I find the low 20-60hz area on the m235i to be no existent.
I did replace all the speakers but the best improvement came from replacing the amp and tuning the low end specifically in the 20-60HZ hertz......What a difference!!
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      11-26-2019, 04:04 PM   #8
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Integral Audio does parts specifically for BMW. Their underseat woofers are amazing for the price, they're listed as for the 3 series but I installed them in my M235i with the "HiFi" system and they fit perfectly. Sound upgrade is amazing, they're usually on sale for about $250 for a pair with adapters and spacers. Easily the best value option available at that price and likely one of the better sounding.
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      11-27-2019, 05:57 AM   #9
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Good to know, probably going to try those out! The earthquakes also look interesting. What would be the best drop in amp valuewise to push the hifi and 300-500watt subs? 2017 m240i prelci
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      11-28-2019, 04:30 PM   #10
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Quote:
Originally Posted by Lozza47 View Post
Hi all,

Does any one have any recommendations for the best direct fit under seat sub upgrade over Hi Fi sound system in m235i?

A lot of threads are based on improvements over HK system.

I won't be changing the amp either.

Alternatively, if you could only do one - would changing out the speakers or changing out the amp for something like bimmer tech's harness the best audio performance improvement?

I find the low 20-60hz area on the m235i to be no existent.
Just did this, sounds great and for $200. Already got the Ghost subs and was greatly disappointed. They need more power sent to them to preform and didn't want to get into modifying the original system. Knowing what I know now I would go with the 8" Rockwell sub. It would be easier to fit and I have the 10" only turned on up about a quarter of the way.

https://www.bimmerpost.com/forums/sh...php?p=25326809
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      11-28-2019, 09:51 PM   #11
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Quote:
Originally Posted by Lozza47 View Post

I won't be changing the amp either.
Then you shouldn't bother with the subs. The subs weak link is power not the architecture of the driver. You'd be better off keeping the factory subs with a better amp to drive them.

Seth
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      11-28-2019, 09:58 PM   #12
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Quote:
Originally Posted by Lozza47 View Post

Alternatively, if you could only do one - would changing out the speakers or changing out the amp for something like bimmer tech's harness the best audio performance improvement?
If you could only do a single thing change your front 2 speakers to a coax set w/passive crossover.
(since removing/unplugging the center channel is free: do this too).

If you were to do that single thing but a touch fancier, move that coax to separates/components with passive crossover and the OEM sail panels to house the tweeter.

Either way, with the door card off dampen the door before reassembly.

Those front door speakers are the single weakest area in the car.

Seth

P.S. the summary from the million threads on audio for 'proper' upgrade path is:

1) remove front center speaker

2) replace door speakers with coax* and dampen doors
2a) *component

3) replace rear fill w/passive coax

4) replace amp
4a) replace amp/processor
4b) replace amp/processor/run active crossover not passive

5) replace subs
5a) remove subs and use trunk sub instead
5b) bandpass filter underseat subs and use trunk sub for low fill
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      12-02-2019, 02:27 PM   #13
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Sethwas has a great list here:

I did 1), 2a) and 5) so far.
I agree that the Amp has to go at some point, and some equalization control would be a give help, so 4a) would be it for me.

The reason I did the subs first is the cost of a decent amp is well over $1000CDN while subs were less than $300. The base is pretty good with the earthquakes, but the stock equalization tuning in the HIFI system is terrible once you have installed components and better subs.
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      12-03-2019, 11:55 AM   #14
sethwas
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Quote:
Originally Posted by Aspen235 View Post
but the stock equalization tuning in the HIFI system is terrible once you have installed components and better subs.
That's the key point. Users here have had good success with the JBL amp and its tuning out of the box with JL audio C2x in the rear, with morel hybrid up front. No change in sub.

Seth
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      12-04-2019, 04:25 PM   #15
Lozza47
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Quote:
Originally Posted by sethwas View Post
Quote:
Originally Posted by Lozza47 View Post

Alternatively, if you could only do one - would changing out the speakers or changing out the amp for something like bimmer tech's harness the best audio performance improvement?
If you could only do a single thing change your front 2 speakers to a coax set w/passive crossover.
(since removing/unplugging the center channel is free: do this too).

If you were to do that single thing but a touch fancier, move that coax to separates/components with passive crossover and the OEM sail panels to house the tweeter.

Either way, with the door card off dampen the door before reassembly.

Those front door speakers are the single weakest area in the car.

Seth

P.S. the summary from the million threads on audio for 'proper' upgrade path is:

1) remove front center speaker

2) replace door speakers with coax* and dampen doors
2a) *component

3) replace rear fill w/passive coax

4) replace amp
4a) replace amp/processor
4b) replace amp/processor/run active crossover not passive

5) replace subs
5a) remove subs and use trunk sub instead
5b) bandpass filter underseat subs and use trunk sub for low fill
Thanks for that run down.
I just recently installed some Hertz 100.3 coax speakers. They are awesome.
I'll put a review up shortly.
I also added a foam spacer around the edges to direct the sound through the grills better due to the lower mounting position.

The high frequencies are a bit harsh only due to the amp I would imagine and the original bmw speakers not having tweeters so the amp pushing the signals up.
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      Yesterday, 01:35 PM   #16
sethwas
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Anytime,

And your assessment of the EQ is spot on.

Seth
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