[Centuari]

I'm looking into getting the base HiFi system in the 2023 m240i upgraded to a custom audio solution.

The hifi has fewer speakers built into the car than the HK system, so I'd assume that a custom solution building off the hifi would be less good than a custom solution building off the HK.

Any knowledge or experience about this? How big a difference does it make?

[CTGT2005]

Most of the benefit from the HK system is going to come from the EQ sound processing that is on the HK system. The factory Hifi speakers are not bad for reasonable listening volumes. I've measured both the Hifi and HK midrange drivers, which perform almost the same in terms of frequency response and distortion. I can share some THD graphs of both when I can get back to my PC.

The limitations of the Hifi system is they do not run a low pass on the midrange allowing it to play well into the 10-15khz range and the tweeter only runs a 6db high pass which keeps it playing down to frequencies that distortion may be audible. The midrange also has a peaking upper response on the Hifi system that makes the sound less full and a bit grainy. There's a wide band between the mid and tweeter that overlaps killing the imaging and clarity of the sound.

If you do end up going with upgraded speakers, go with components that offer a dedicated high and low pass filter combination. I am putting Morel IR-42 Reference speakers $$$ in my car soon, which barely measure from a harmonic distortion perspective better than the factory Hifi speakers in most frequencies.

If I were trying to spend my money best bang for the buck, go with an audiotec fisher match amp or bimmertech amp first, swap the tweeters with some upgrade silk domes like come in the morel system mt-250, add a 2nd order hpf/LPF 3.5khz and put a dedicated 10" subwoofer in the trunk. Skip the underseat woofers if you want real bass. The underseat woofers need to play well into the the 100-200hz range to pick up with the midrange leaves off. Switching them to more powerful woofers to bring up sub bass frequencies ends up muddying the midbass and doesn't integrate well with the rest of the front stage

[Centuari]

Originally Posted by CTGT2005

Most of the benefit from the HK system is going to come from the EQ sound processing that is on the HK system. The factory Hifi speakers are not bad for reasonable listening volumes. I've measured both the Hifi and HK midrange drivers, which perform almost the same in terms of frequency response and distortion. I can share some THD graphs of both when I can get back to my PC.

The limitations of the Hifi system is they do not run a low pass on the midrange allowing it to play well into the 10-15khz range and the tweeter only runs a 6db high pass which keeps it playing down to frequencies that distortion may be audible. The midrange also has a peaking upper response on the Hifi system that makes the sound less full and a bit grainy. There's a wide band between the mid and tweeter that overlaps killing the imaging and clarity of the sound.

If you do end up going with upgraded speakers, go with components that offer a dedicated high and low pass filter combination. I am putting Morel IR-42 Reference speakers $$$ in my car soon, which barely measure from a harmonic distortion perspective better than the factory Hifi speakers in most frequencies.

If I were trying to spend my money best bang for the buck, go with an audiotec fisher match amp or bimmertech amp first, swap the tweeters with some upgrade silk domes like come in the morel system mt-250, add a 2nd order hpf/LPF 3.5khz and put a dedicated 10" subwoofer in the trunk. Skip the underseat woofers if you want real bass. The underseat woofers need to play well into the the 100-200hz range to pick up with the midrange leaves off. Switching them to more powerful woofers to bring up sub bass frequencies ends up muddying the midbass and doesn't integrate well with the rest of the front stage

Really appreciate the detail here, thank you.

Because you've clearly thought about this, do the increased number of speakers in the hifi vs. HK make much of a difference in terms of upgradability?

[CTGT2005]

Originally Posted by Centuari

Really appreciate the detail here, thank you.

Because you've clearly thought about this, do the increased number of speakers in the hifi vs. HK make much of a difference in terms of upgradability?

I may be a little biased as I started with the Hifi system and upgraded.

The speakers themselves are all the same size for the HK vs the Hifi system just more of them. You also start with more power on the HK amp, but need a more expensive amp if you upgrade later, which will be required to properly tune the system. Similar upgrade options exist for amps HK vs Hifi. In terms of aftermarket speaker products they will be the same across both HK and Hifi, you'll just need 2 more units of midrange speakers from the rear parcel shelf and 4 more tweeters 2x rear quarter panel and 2x rear parcel shelf. There is no room for anything more than 2" deep in the doors and they all use a specific BMW 3 hole mount, so your limited to aftermarket application specific units mostly.

If you want to fully upgrade an HK system you'll spend 50-75%% more on the parts, plus the upcharge to get it new from the factory. The only benefit of having more low quality speakers is you can get a 3-5db increase in output at similar distortion levels without using actual high end components. You also get better control over time alignment and can post process an appearance of detail/depth into the soundstage. Personally I'd rather focus my $ on having the best components albeit less units. 80% of the information in the music is coming from the front left and right channels.

Nothing is going to give true audiophile sound in this car. Between 60db of floor noise, being stuck with 4" drivers in the front stage and the midbass/bass coming from small boxes under the seats. Any kind of amplifier upgrade is just a bandaid that sits on top of the OEM amplifier and increases the wattage while retaining the factory high level signal. My focus would be getting decent subwoofer bass, smoothing out the midrange and treble response and getting the issues with the factory mid/tweeter crossover taken care of first. At that point you're probably at the point of diminishing returns.

[Rx-7ames]

Originally Posted by Centuari

I'm looking into getting the base HiFi system in the 2023 m240i upgraded to a custom audio solution.

The hifi has fewer speakers built into the car than the HK system, so I'd assume that a custom solution building off the hifi would be less good than a custom solution building off the HK.

Any knowledge or experience about this? How big a difference does it make?

I'm a little late. I don't visit this section often, but I think I can help. If you plan to upgrade your audio system then there is no reason to pay extra for HK, then upgrade that.

Just get the hi-fi system. You will upgrade the front door speakers and tweeters, underseat subs, and amplifier. Then if you want to you can upgrade the rear speakers, but it isn't necessary. This will give you more than enough of an upgrade.

People run into a problem when they think that more speakers will make a sound system better. HK is just adding more speakers, a slightly more powerful amp, and better sound tuning. All of this is going to be replaced with better parts if you do an upgrade.

Basically, don't waste money on HK just to replace it. Save the $875 and spend that towards upgrading the Hi-fi. You'll be better off that way.