Alex-ander wrote

I though this was interesting. I’m running pink noise thru the input Rta and look how much the factory amp KILLS the upper frequencies! They pretty much boosted all the mids and cut all the highs. Flattening out the curve makes a HUGE difference! I believe THATS where having the dsp on this system is gonna come in handy, not just the implication but the Eq correction!

EWL5 wrote

Folks were wondering why I thought the timbre of Sports talk hosts sounded different in this car than any other car!

At least now we have technical proof that BMW "didn't even try"!

jinetix wrote

I have direct experience upgrading both the Hi-Fi and HK setups fully and in phases (iDrive 7 models only). I upgraded my 2021 M40i with Hi-Fi and my buddy's 2021 X3M w/ HK. My M40i now actually has a full factory HK retrofit (HK RAM + Booster + D-pillar speakers).

This is what I learned from my experience upgrading both.

The Hi-Fi setup is powered completely by the RAM module and the 10w mid-ranges and tweeters are absolute garbage. Adding an amp helps with volume but the speakers really hold it back when it comes to detail, clarity, and power. The amp pretty much amplifies everything coming from the RAM, and due to the RAM being so weak, I found that the sweet spot for the gain for the Hi-Fi setup is bumping it up 3 notches in the Match/Bimmertech amps (it's a notched slider in the software). However, the noise floor is much higher on the Hi-Fi setup, so bumping it up 3 notches, you will hear the faint hissing from the noise floor when the cabin is quiet. Due to this, bumping it up just 1-2 notches is ideal. This is one of the main reasons why I think getting the factory HK is worthwhile, and is why I retrofitted the factory HK to my vehicle.

The HK setup is different in that the speakers are powered by two amps, the RAM and the Booster. The RAM powers the mid-ranges and tweeters, while the booster powers the 8-ohm underseats. Due to the RAM not being responsible for powering the underseats, I found that the RAM drives the midranges and tweeters with a lot more power which in turn made it so you couldn't discern the noise floor bumping up the gain further compared to the Hi-Fi setup. The hearsay portion of the amp upgrade is based on how much of an audiophile you are. If you've been spoiled by a nice home theatre system or a nice pair of cans, the HK will be lacking even with an amp added and tuned. The HK underseats serve as a good mid-bass driver, so replacing them with a pair of aftermarket 2-ohms will remedy that and satisfy most users (can get as low as 30-40hz depending on driver). If you're young and want to feel the hairs on your body when the bass drops, you'll def need a true sub.

Get the Morel underseats. After testing a handful, I found that they get as low as the best 2-ohm underseats on the market while extending up to where the mid-range drops off in freq.

d4700 wrote

Hi, sorry to necro this thread.

I've been digging a bunch trying to find out what the process is like to upgrade from HiFi to Top HiFi on a RAM equipped car. I understand that I'll need to swap from my current RAM Mid to RAM High, as well as retrofit a Booster High.

Did your car come pre-installed with a booster? If not, what was the wiring like? I understand that I'll basically need to swap the subwoofer lines from the RAM to the Booster, but past that, I'm a bit lost. For now, I'm just looking to upgrade the subs and pick away at the other speakers when time allows.

Would greatly appreciate your input!

das boots wrote

The HK on my 2005 330i ZHP sound a whole lot better and solid with no amps adjustments than the HK on my G02.

jinetix wrote

No, I sourced a booster and HK RAM from eBay and flashed them with E-SYS to match the car (TAL calculation -- make sure you have HWIDs from SVTactual selected to avoid bricking them). It has been a while since I've done the retrofit so I don't recall all of the details, but you have the right idea. You swap the underseat woofer wires for the D-pillar speaker wires on the RAM harness. You put the underseat woofer wires in the booster harness. You run the ethernet data lines from the RAM to the Booster. You splice into the ethernet wake up wire on the RAM with the one on the booster so both wake up and go to sleep together. Then you run the power wires from the rear fusebox to power the booster. Mine came with pigtails cut off, but if you get one without, you'll need to order the proper connectors and terminal pins. You should get the wiring diagrams and pinouts for the RAM and Booster from ISTA+.

I ended up getting an ethernet decoder box which completely bypasses my HK retrofit though. If you're just chasing better sound quality, you can do what I did and get the ethernet box to extract the digital signal from the MGU, bypass the RAM, and use a 10DSP to run all of the speakers (if you want the D-pillar speakers, otherwise an 8DSP will work).

jinetix wrote

No, I sourced a booster and HK RAM from eBay and flashed them with E-SYS to match the car (TAL calculation -- make sure you have HWIDs from SVTactual selected to avoid bricking them). It has been a while since I've done the retrofit so I don't recall all of the details, but you have the right idea. You swap the underseat woofer wires for the D-pillar speaker wires on the RAM harness. You put the underseat woofer wires in the booster harness. You run the ethernet data lines from the RAM to the Booster. You splice into the ethernet wake up wire on the RAM with the one on the booster so both wake up and go to sleep together. Then you run the power wires from the rear fusebox to power the booster. Mine came with pigtails cut off, but if you get one without, you'll need to order the proper connectors and terminal pins. You should get the wiring diagrams and pinouts for the RAM and Booster from ISTA+.

I ended up getting an ethernet decoder box which completely bypasses my HK retrofit though. If you're just chasing better sound quality, you can do what I did and get the ethernet box to extract the digital signal from the MGU, bypass the RAM, and use a 10DSP to run all of the speakers (if you want the D-pillar speakers, otherwise an 8DSP will work).

d4700 wrote

Excellent writeup, thanks! Getting ready to pull the trigger on a new RAM and Booster now. The 8DSP was enticing, but considering that I can get the subwoofers and modules on eBay for $500 total, I'll probably be happy with that for a while. I'm a sucker for the Logic7 surround effects even if the overall quality isn't the greatest.

At least on my car, I saw that the booster would be hooked up to fuses 214 and 217 in the rear power distribution box. Were you able to use the typical auto parts store "fuse taps" (the ones with two fuses and a wire sticking out) in these spots, or are they not pre-wired?

jinetix wrote

I used the factory location for the booster. On my amp bracket there is an empty area on the back of the bracket the booster normally goes. Is there not a factory location for the 5 series? I would look up where it goes for HK equipped 530e vehicles.

I added a fusebox terminal from behind, the fusebox panel is easy to remove to get access to the back. The add-a-fuse method should work fine though.

d4700 wrote

Unfortunately, the bracket I have doesn't have any good mounting point for the booster. Did some digging and not only is the bracket part number different for HK-equipped 5 series, but the cubby in my trunk is also too large to mount the booster in the stock location. Shouldn't be a problem - I don't mind getting creative with the mounting location. Duct tape may be involved...

Final question for you (sorry - you're literally the only person I know of who's documented this process online), did you lose your FSC codes for active sound design and Sirius XM?

Appreciate your help, I've been daydreaming about tackling this project for ages now and only pulled the trigger once I saw your success with it.

jinetix wrote

I have direct experience upgrading both the Hi-Fi and HK setups fully and in phases (iDrive 7 models only). I upgraded my 2021 M40i with Hi-Fi and my buddy's 2021 X3M w/ HK. My M40i now actually has a full factory HK retrofit (HK RAM + Booster + D-pillar speakers).

This is what I learned from my experience upgrading both.

The Hi-Fi setup is powered completely by the RAM module and the 10w mid-ranges and tweeters are absolute garbage. Adding an amp helps with volume but the speakers really hold it back when it comes to detail, clarity, and power. The amp pretty much amplifies everything coming from the RAM, and due to the RAM being so weak, I found that the sweet spot for the gain for the Hi-Fi setup is bumping it up 3 notches in the Match/Bimmertech amps (it's a notched slider in the software). However, the noise floor is much higher on the Hi-Fi setup, so bumping it up 3 notches, you will hear the faint hissing from the noise floor when the cabin is quiet. Due to this, bumping it up just 1-2 notches is ideal. This is one of the main reasons why I think getting the factory HK is worthwhile, and is why I retrofitted the factory HK to my vehicle.

The HK setup is different in that the speakers are powered by two amps, the RAM and the Booster. The RAM powers the mid-ranges and tweeters, while the booster powers the 8-ohm underseats. Due to the RAM not being responsible for powering the underseats, I found that the RAM drives the midranges and tweeters with a lot more power which in turn made it so you couldn't discern the noise floor bumping up the gain [...]

arhoads335i wrote

Hi I have a 2023 with HK system. Interested in bumping up subs but I don’t want a standalone sub in trunk. What replacement under seat drivers do you suggest?

arhoads335i wrote

Well the above guy stated using 2 ohm speakers might have a better outcome. So just looking at options

ASAP wrote

I know there is a lot of hearsay on these forums but after reading over and over I've only learned 2 things -


2) for the HK stereo, the real problem is lack of a true subwoofer not really poor speakers nor a weak amp

EWL5 wrote

So what are you running at home?

Whenever car audio messes w/the timbre of familiar hosts on FM radio, that catches my ear in the worst way (as it did for my HiFi system)! Cheaper speakers in the G45 HK system possibly could have the same effect, especially w/the reduction in the number of tweeters!

G01 HK system grade from DM Sound: B+

G45 HK system grade from DM Sound: C-

Same guy, same baseline tests. I guess most BMW owners are tone deaf!

Bimmerforlife wrote

Why is the BMW i4 HK so much better that he gives it an S Tier (highest rating). Why does the i4 HK sound better? It only has 1 extra speaker.