G05
BMW X5
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04-17-2026LAST POST
11-23-2025
Coercion Shaman wrote
I had a chance to run a cheap sub. The immediate benefit was obvious. Found a great deal on an Audison APBX 10 AS2 Prima Series 10" that arrives Monday.

Now I am considering the Helix Ci5 upgrade to the under seat mentioned here for the mid bass. Thoughts on the benefit?
I have the same Audison APBX 10 AS2 in the X5, under the trunk floor. It is awesome, with plenty of power. Plays down to around 26-27Hz (the factory signal starts dropping around 30Hz).

As far as underseats. There are quite a few. They perform similarly in the BMWs, due to their not so ideal location. But if you get things adjusted correctly, they will be fine.

The Ci5s are relatively new, but seem to be quite successful.
Many people installed them in various cars. Most seemed to like them.
Do you have an Amp installed to power the Ci5s?
11-23-2025
I have the match 8 installed.
11-24-2025
dombi's user avatardombi, I just saw your setup in the subwoofer thread. Where do you have your DSP? And it looks like you have both RCA lines connected. Did you run a splitter off the line out?

I have been going back and forth with myself this weekend on the install. I have a spare, but I have debated pulling that and selling it. I have 21's and not sure how the 19" spare would do anyway. Plus I pay for AAA for my wife and I carry plugs and a pump. It would make a much cleaner install after seeing yours. It wouldn't be a huge ordeal to pull the sub if I mounted on top and needed space, though.

Still debating the Helix. Guess I will run a while and build from the file that Theruleslawyer's user avatarTheruleslawyer posted out and determine if I need them. Just saw a really good deal on them, but money spent when not needed is gone. And I don't want to rabbit hole since I have already considered getting the Focal K2 to replace the 100L I already changed out.
11-24-2025
Coercion Shaman wrote
dombi's user avatardombi, I just saw your setup in the subwoofer thread. Where do you have your DSP? And it looks like you have both RCA lines connected. Did you run a splitter off the line out?

I have been going back and forth with myself this weekend on the install. I have a spare, but I have debated pulling that and selling it. I have 21's and not sure how the 19" spare would do anyway. Plus I pay for AAA for my wife and I carry plugs and a pump. It would make a much cleaner install after seeing yours. It wouldn't be a huge ordeal to pull the sub if I mounted on top and needed space, though.
Still debating the Helix. Guess I will run a while and build from the file that Theruleslawyer's user avatarTheruleslawyer posted out and determine if I need them. Just saw a really good deal on them, but money spent when not needed is gone. And I don't want to rabbit hole since I have already considered getting the Focal K2 to replace the 100L I already changed out.

The DSP is mounted on the same bracket as the RAM module.
This is what my installer came up with. Not the prettiest solution, but it works.

Yes on the RCA splitter.
DSP's RCA output -> RCA splitter -> Sub's L + R input.

Here are some pics for you. Hopefully they will help.

Speakers: get the tuning sorted out. Very important.

Time alignment / phase alignment on the Woofers + Sub.
Ideally, the left and right sides should follow the curve, on their own. And the summed response should do the same.

You can get the most expensive speakers... but if your tuning is off, it will not sound good.

I am extremely happy with the 100Ls. I can't even imagine what the more expensive speakers would sound like. :)

An image attached to this post, provided by the poster
An image attached to this post, provided by the poster
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An image attached to this post, provided by the poster
12-05-2025
Did a very similar installation as dombi's user avatardombi last weekend. Used the tune Theruleslawyer's user avatarTheruleslawyer had posted with his sub install. Need to run the bass remote to the front and tweak out the tune, but very pleased so far.
12-06-2025
Coercion Shaman wrote
Did a very similar installation as dombi's user avatardombi last weekend. Used the tune Theruleslawyer's user avatarTheruleslawyer had posted with his sub install. Need to run the bass remote to the front and tweak out the tune, but very pleased so far.
Can you measure phase for the Sub?
If not, you can use the nulling method also, to get it close to the rest of the system.
12-11-2025
dombi wrote
Garry: sorry to hear about the TPMS.
Hopefully they can solve it quickly for you.
Dombi,
Sorry I haven't forgotten about this - my car is still at the dealership with this crazy intermittent TPMS issue. It's been there for about 3 weeks total.

It isn't exactly encouraging when you get this from them today:

TSARA (BMW engineering Global) is even a bit mystified, this is a journey for sure
--BMW of Anchorage


When I get it back I'll figure out how to run the sweeps!

If you're curious about the TPMS issue, I get an error on the dash stating Tire Pressure Monitor Malfunction. It doesn't happen regularly or seem to be related to temperature or location. It'll happen randomly driving down the road. (See the attached pic). They've replaced the TPMS sensors on the wheels (I even had a spare set of winter tires with aftermarket TPMS - makes no difference) replace the TPMS antennas, upgraded the firmware on the car, all sorts of things.


-G
An image attached to this post, provided by the poster
12-22-2025
Just finished adding BimmerTech's Alpha One and their Impedance Box to my 50e, and I'd like to sincerely thank everyone here with their posts and ideas; very helpful. I ended up using one of the tune files from here (MGU 688 LHD BTL) versus the G05 tune file that BimmerTech shipped the amp with; it got the settings really close to what I like and, seemingly, what the speakers can handle. Next steps are some tweaks using a tuning USB mic, and eventually a powered sub install to get those lower frequencies; however, that may take some thought since I don't have a spare tire well to use.
12-22-2025
eljackso wrote
Just finished adding BimmerTech's Alpha One and their Impedance Box to my 50e, and I'd like to sincerely thank everyone here with their posts and ideas; very helpful. I ended up using one of the tune files from here (MGU 688 LHD BTL) versus the G05 tune file that BimmerTech shipped the amp with; it got the settings really close to what I like and, seemingly, what the speakers can handle. Next steps are some tweaks using a tuning USB mic, and eventually a powered sub install to get those lower frequencies; however, that may take some thought since I don't have a spare tire well to use.
I have the Audison APBX 10 AS2 under the trunk floor.

When my installer set it up for me, we discussed the choices for location:
- first we placed it under the trunk floor, to see if it sound good from there.
- if that would not have worked out, we would have placed it on the trunk floor.

The first option worked out great for me. The Sub sounds great from under the floor. It creates no rattles, and it can be tuned to blend with the underseat Midbass.

But the Sub is easy to move from one location to the other. The installer left me enough cable lenght to play with.

And the sub is quite compact for what it is (10”) sealed with built in Amp.

The Sub can be disconnected quickly/easily from the Match UP amp/dsp, if I ever need the space back. This could work for you too -> connect it or disconnect it quickly.

This model has a strong enough case/box, so you can place/store things on top of it, if you have to.

Awesome little Sub. Never regretted it.
With my tune, and with the factory signals, it plays down to around 25-26Hz.
01-01-2026
dombi wrote
With my tune, and with the factory signals, it plays down to around 25-26Hz.
Did you do anything specific in your tune to get that low (low shelf, low frequency narrow filters)? Getting ready to add a sub and looking at the input signal it starts to drop off at 40hz and anything below 35 is very low.
01-02-2026
Rosetta Stoned wrote
Did you do anything specific in your tune to get that low (low shelf, low frequency narrow filters)? Getting ready to add a sub and looking at the input signal it starts to drop off at 40hz and anything below 35 is very low.
Yes. The factory signal in my HK system starts dropping around 32ish Hz (I don’t have my measurements with me… travelling at the moment). But the level of the Sub is also higher than the Doors…

How the Sub is set up:
- the Sub’s input = Woofer L+R
- input gains were adjusted for all inputs (Woofers too)
- factory Woofer levels already play higher than the doors
- the Amp’s dial on the Audison is turned up about half way.

With the above setup, the Audison has plenty of power, and is playing well above the rest of the system (in level).

Check your Sub’s FR without any filters, XOs. See where the null is in your car.
I think my Sub’s null is at 100Hz. So I tried to stay away from it, which is why the XO between Sub and Woofers is at 60Hz.

I EQd the Sub’s response to my liking (LP is 60Hz/LR24 crossover + EQ to house curve).

After EQ, the EQd response extends below 30Hz and it starts dropping close to mid 20s.

Give it a try.
01-18-2026
elibol wrote
Here is the tune file. Here are some notes to keep in mind:
  • I don't think anything is muted (someone else can confirm), so make sure to have your volume all the way down before loading.
  • It is time aligned. I don't think this should matter from vehicle to vehicle, but it is certainly worth double checking (if you have nothing better to do).
  • The drivers are *not* measurably leveled. The leveling is just how I like things to sound. I level while tuning (to match my house curve), and then level afterward to how I like things to sound. That said, level before you phase align. Leveling after phase alignment can break phase between drivers.
  • The underseat virtual channel is set up to be as flat (w.r.t. to achieving a full freq spectrum) as possible without messing around with input EQ. I think it's as good as you can get without messing around with the stock input signals. Keep in mind, changing the input signal impacts all virtual channels that depend on that input signal. I'm not saying that messing around with input signals is a bad thing. I just think that, if you're going to do it, you should know what you're doing :)
  • The input signals to all other virtual channels are unaltered.
  • The front/rear/surround speakers all go down to 80hz. This is roughly equivalent to letting the built-in high-pass filter do its job. There is a distinction to be made here between *acoustic* vs. *electrical* crossovers: The built-in crossover is the electric crossover. When you tune a specific channel with a mic, ignore the electrical crossover and look at what the speaker can actually do in RTA. For us (G05 w/ HK S668A), it will drop off well above 80hz. I don't recall exactly the best crossover for HK underseats and door speakers, but I *think* it's around 150hz. That said, the ci5s do in fact go higher (with a mixed front door and underseat speaker mix to virtual underseat like I have in the tune file) :)
  • The tune file assumes a trunk sub. If you do have a trunk sub, retune the phase accordingly. If you don't have a trunk sub, ignore the sub channel and set your underseats to go all the way down to 20hz (or bypass). With no trunk sub, you'll want your underseats going as low as they can go. Also I want to echo the order of upgrades Theruleslawyer's user avatarTheruleslawyer originally laid out: DSP first, then trunk, then door speakers, then underseats. That is also IMO the most impactful order of upgrades.
  • The underseat gain (in DCM) is at its lowest level. I honestly can't remember whether this was the correct setting for the HK underseats or whether I did this after installing the ci5s. Just something to keep in mind. That said, I'm pretty sure this setup is going to max out the HK underseats with minimal distortion at higher volumes, so I don't think it's a good idea to crank the gain any further. If you do increase gain, make sure to do it properly (with volume maxed and speakers muted). It's really easy to push the HKs to distortion.
  • The EQ per channel are all reset. You'll need a decent mic to tune. I used to use a crappy mic (Dayton Audio iMM-6), but it wasn't great at picking up sounds without cranking both the mic and the volume to the max. I have had an easier time tuning with the UMIK-1. I got the Dayton after watching Raw-Cat's review of a bunch of mics and claiming they are all equivalent, but I did not experience that to be the case in practice. That said, I find about 80% of what that dude says to be 100% accurate (60% of the time, it works every time). He is 100% out to help us DIYers.
tsv5513's user avatartsv5513 specifically for you, I don't have the MEC. I believe that's for center channel. My tune file assumes no MEC (the center channel is mixed left/right with "true center" or whatever they call it enabled in DCM). I have found the center channel is nice to mess around with *after* you have figured out everything else, but perhaps this may be different with the MEC.

Anyway, hope this is helpful. If it's not working out for you then just do your own thing and continue asking questions. It's a fun and rewarding process.
I used your file as a starting point, sounds awesome! thanks
01-23-2026
For anyone who could find it usefull, here's my soundfile for the Matchup10DSP adjusted to my liking.

At this moment I have the following setup:

OEM HK speakers (will be replaced by ALPHA ONE soon)
JL audio 8 inch sub in sealed box
Matchup 10 DSP
Mosconi D2 500.1 external amp

swap PDF with .afpx and you are good to go.

An image attached to this post, provided by the poster
01-26-2026
Marc R wrote
For anyone who could find it usefull, here's my soundfile for the Matchup10DSP adjusted to my liking.
Nice. Good job.

You did the crossovers and time alignment, right?
How do you like the tune?

If you want to go one step further you can get a measurement mic.
With the measuring mic you can measure the response of your speakers.

The response graphs help to see what the individual / summed speaker responses look like.
01-26-2026
dombi wrote
Nice. Good job.

You did the crossovers and time alignment, right?
How do you like the tune?

If you want to go one step further you can get a measurement mic.
With the measuring mic you can measure the response of your speakers.

The response graphs help to see what the individual / summed speaker responses look like.
Yeah I like it like this, after I swap the HK speakers out for the ALPHA ONE set i'll do another round with the DSP settings.

the good stuff.
02-06-2026
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03-02-2026
I just upgraded to the AlphaOne/MatchUp10DSP amp with the AlphaOne under seat subs - from the X5 Harmon Kardon system. If I had to give it a rating, if the Hifi system is like a 5/10, HK is maybe 7/10, the Alphaone amp with the Alphaone subs bring it to an 8/10. Although it is better, I think it's missing the depth of the bass and the under seat subs even upgraded with the AlphaOne, lacks the bass.

Anyone have options to get better bass? I don't want a big box in my trunk. Maybe I'd get rid of the spare tire and put something there? Does anyone know of some custom sub enclosures that blend in better?
03-02-2026
BMWM3Rules wrote
I just upgraded to the AlphaOne/MatchUp10DSP amp with the AlphaOne under seat subs - from the X5 Harmon Kardon system. If I had to give it a rating, if the Hifi system is like a 5/10, HK is maybe 7/10, the Alphaone amp with the Alphaone subs bring it to an 8/10. Although it is better, I think it's missing the depth of the bass and the under seat subs even upgraded with the AlphaOne, lacks the bass.

Anyone have options to get better bass? I don't want a big box in my trunk. Maybe I'd get rid of the spare tire and put something there? Does anyone know of some custom sub enclosures that blend in better?
You need to get the system tuned. You can get the Bass to sound quite good with the underseats too.
Which iDrive version do you have? iD7 or iD8?

If you want to add a Sub, there are plenty of options out there.
I have this one, works really good.
https://audison.com/product/apbx-10-as2/

But even if you add a Sub, you still want to get the system tuned.
03-02-2026
I have a 2024 X5 M60 with the HK system and now the Bimmer-tech/MatchUp10 DSP with the AlphaOne underseat subs. Can anyone share their DSP file with more bass depth?

Thanks in advance.
03-02-2026
BMWM3Rules wrote
I have a 2024 X5 M60 with the HK system and now the Bimmer-tech/MatchUp10 DSP with the AlphaOne underseat subs. Can anyone share their DSP file with more bass depth?

Thanks in advance.
Do you have time alignment set?

By default, the Woofers’ time alignment is not ideal.

I don’t have iD8 measurements. But on iD7 the Right Woofers’ time alignment/delay needs to be reduced by 1.5 ~ 2.0 ms, to get it in time with the Left. Which would result in better Bass response.

If you have to Time Alignment set yet, then you can achieve this by adding 1.5 ~ 2.0 ms to each channel, keeping the Right Woofer on 0.

Ideally you would want to time align all speakers. If you want to try it, can send you the delay vales I have for iD7…
03-02-2026
dombi - I got the amp from Bimmer-tech and supposedly they have a set DSP file preinstalled? So I haven't done anything with the DSP settings.
03-02-2026
Your system could probably sound much better.
But it does not have the correct settings in the DSP.

Ideally, your system needs to be measured.
Then adjusted based on those measurements.

I don't know how Bimmer-tech does things. So I cannot comment on that.
Maybe they can send you a different settings file... but that probably won't be perfect either.

Maybe you can find a tuner in your area, that could do a proper tune for you.

There are also companies in the US, who to remote tuning.
They send you all the equipment needed for the tuning (w/ probably some instructions), then do the tune for you remotely. Then you send the equipment back.

Or you can try to do the tuning yourself...