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      01-03-2019, 06:49 PM   #89
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The Maserati sound module arrived today and I just hooked it up. The engine growl is significantly deeper and louder than the Maxhaust sound module. I did not take the car out of the garage though as its snowy/icy/salty here in Wisconsin and I just spent 3 full days putting on a semi-permanent coating over the holidays. (Waxless wash, full rinse & wipedown, Iron-X, Isopropyl wipedown, Carpro Essence with buffer, Carpro Eraser Wipedown, CQuartz UK 3.0 (2 coats with another Eraser wipedown between), Carpro Reload) So I'm in no hurry to get her dirty...

So far the Maserati Sound Module sounds much better than the Maxhaust Sound Module. The weather is supposed to get pretty good here over the weekend (45F and Sunny) so maybe I'll pull her out of the garage and take her for a spin if the roads are dry. I'll also get some comparative audio clips if I can.

One interesting point worth noting! ANYONE should be able to switch between the two sound modules (Maserati and Maxhaust) just by using the connector in the MIDDLE of the harness. You don't have to do the connector mod like I documented since you will continue to use the Bluetooth harness which is already wired into your car. Only the downstream sound module half of the harness gets swapped out when the modules are changed and it has its own connector. IOW: If you already have one of the modules installed, you can very easily switch to the other by simply unplugging one sound module harness and plugging in the other!

I'm still in favor of the connector mod as I think it makes a cleaner install (and you can also easily switch back to factory BMW sound) but if you already have the wiring done, you can easily switch between Maxhaust and Maserati sound modules. All you need to do is reload the car definition through the app once you switch modules.

It should also be noted that they finally released an Android app compatible with the new Maxhaust sound module (and the original Maserati Module).

If you broke the BMW pins when trying to insert them into the "Blue Connector", Maxhaust can also send you replacement pins if you want to try and do my connector conversion. This would let you effectively rebuild your BMW wiring harness if you have a crimper, soldering iron, and some patience. As I was ordering the Maserati module from them anyway, I asked them if they had any (they did) and if they could send them to me (they would) before I did the conversion just in case I broke mine while trying to remove them from the Blue Connector (I didn't). (I ended up doing a very destructive "forensic autopsy" on the Blue Connector to extract them to avoid breaking them as I wasn't going to reuse the blue connector anyway...)

So... If you are happy with your current wiring and want to try the "other" sound module, you should know they are plug and play compatible! If you messed up your pins, and still want to implement the "connector upgrade", then Maxhaust can include the pins when your order the "other" module. (Just ask nicely...)
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      01-05-2019, 04:06 PM   #90
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So I got the car out and ran it around the block today. While I think the Maserati Sound Module does sound better (out of the box) then the Maxhaust Module, something is still not right...

I promised everyone to get some high quality side-by-side AUDIO clips so we had something better than a variety of arbitrary iPhone VIDEOS on a bunch of different cars. ...and I'm still going to do that. But a Smart Phone does NOT a good audio recorder make. My original plans were to mount my Tascam DR-05 Stereo Portable Digital Audio Recorder on the rear bumper of the car and record audio while driving through a pre-defined series of events over a very short road circuit (Idle, gentle acceleration, gentle deceleration, spirited acceleration with manual shifting, and engine braking via manual downshifting). I was going to do the same series over the same course for both the Maserati Module and the Maxhaust Module (and maybe even the factory BMW sound module). This should give everyone a pretty complete side-by-side comparison of the difference in sound over a common variety of conditions.

I'm still going to do this but my drive today has given me the incentive to do a bit more detailed analysis...

One of the "shortcomings" I have noted before was the frequency disparity between the fake outside sound (Maxhaust or Maserati) and the fake inside sound (BMW). The fact that our i8's already have some pretty impressive interior sound generation adds a whole new challenge to try and make sure that the outside sound "integrates" properly with the sound being generated inside the cabin. IOW: We don't need the Maxhaust sound to follow the ACTUAL engine RPM (which we DON'T hear), we need the Maxhaust module to follow the RPM of the interior sound (which we DO hear).

Maxhaust makes lots of kits for many different cars and I believe MOST of them do not have interior sound generation. I was hoping the factory default configuration (for both sound modules) would have been better matched to the interior sound being generated by our cars. The good news is that I believe BOTH sound modules (Maserati and Maxhaust) have the ability to tweak the "RPM matching" via the Maxhaust bluetooth controller and app. The adjustment in the app is a bit of a blind alley (it is just a dial from 0 to 100). As I've noted in prior posting: Their tutorial PDF notes that setting "Idle RPM" to 10 and "Dynamic RPM" to 30 will follow the car RPM 1:1...

So what does that actually mean? Is Maxhaust assuming a fixed number of cylinders (4,6,8,...) for all cars when they do their calculations - or do they take into account the actual number of cylinders in our car (3)? ...and "what RPM" are we talking about? Are we talking about the actual engine RPM (which Maxhaust is clearly reading from the CANBUS) or are we talking about the simulated engine RPM being delivered inside the cabin? Based on what I'm hearing, I'm willing to bet they are tracking the actual engine RPM and maybe even basing their sound calculations on a 4 cyl profile. This would explain why their exterior sound is "weak" or "slow" when compared to what is being generated inside the cabin.

Here is where it really gets interesting!

So the engine in the i8 is a 3 cylinder engine. I think we can be pretty sure that BMW is not pumping augmented 3 cylinder engine exhaust sounds into the cabin. (...otherwise the sound we hear in the cabin would be more like a Harley than a Race Car). Its my guess, that in order to avoid audible syncopation, BMW likely chose to emulate the sound of a 6 cylinder or 12 cylinder engine via the interior sound (maybe even a 9 Cylinder). It would seem that using an even multiple of the actual number of cylinders would be a requirement to make the sounds integrate properly.

So, if we were generating a 6 cyl sound on top of a 3 cyl engine we would get an aligned real/fake pulse, followed by a fake pulse, followed by another aligned real/fake pulse, etc. IOW: Emulating a 6 cyl engine on top of a real 3 cyl engine would result in 2 fake exhaust pulses for every real pulse. Fake 12 on top of Real 3 would be 4 fake pulses for every real pulse. Fake 6 on Real 3 = doubled sound frequency. Fake 12 on Real 3 = quadrupled frequency.

In a 4 cycle engine each cylinder goes BANG once every two revolutions. I'm not an exhaust sound expert but it seems to me the dominant frequency of an exhaust sound would correlate with the rate of actual exhaust strokes (bang!) being performed by the cylinders. So, if I'm correct, a 3-cylinder 4-cycle engine running at 5000 RPM should produce a dominant exhaust note at approximately (3 * 5000 / 2) = 7500 pulses per minute or (7500 / 60) = 125 Hz (pulses per second). (I might also be under-rating the freq by a factor of 2 if we count the intake stroke but its all relative in any case). A 2 cyl Harley at 5000 RPM would chug along at 83 Hz and a 12 cyl Ferrari would scream at 1000Hz. I haven't done any research to support this, but I'm quite certain that running an audio spectrum analysis on the wave file (of a actual exhaust sample when the car is running at 5000 RPM) will illuminate the truth! There are lots of free audio apps on the internet which should enable this type of analysis - if I have the sound samples!

So my basic questions are, with our engine running at a particular RPM (I think 5000 is reasonable):

1. What is the frequency of the actual engine exhaust sound?
2. What is the frequency of the fake interior sound generated by BMW?
3. What is the frequency of the fake exterior sound generated by Maxhaust and Maserati sound modules?

I'm willing to bet that number 1 vs 2 is a perfect multiple. (The BMW interior sound is spot on!) However, what I'm hearing leads me to believe that 2 vs 3 is not a perfect 1:1... In fact, in may not even be a perfect multiple.

Maxhaust tells us that setting a couple of parameters to specific values in the app "will follow the car RPM 1:1". (Remember, they are reading the ACTUAL engine RPM from the CANBUS) But with the i8, that's NOT really what we are hearing in the cabin! I think what we want is the simulated EXTERIOR RPM to match the simulated INTERIOR RPM (not actual engine RPM).

So the question becomes: Did Maxhaust set up the i8 definition file specifically for optimization in combination with the interior sound RPM? ...or did they just set it up to match the engine RPM with pre-defined number of cylinders? While what we predominately hear inside the car is the simulated interior sound, even rolling down the window and sticking my head outside seems to indicate they are likely following the actual engine RPM. The result is that the simulated exterior RPM seems to be "weak" when trying to selectively hear it inside the cabin.

Anyway, running a spectrum analysis on some good sound samples obtained both outside and inside the car at a predetermined RPM should provide the answer to most, if not all, of these questions. By disconnecting any/all exterior sound modules, I should be able to get a clean sample of the actual engine exhaust sound (RPM). I'm also curious what the frequency tracking of the factory BMW exterior sound module is (With my connector mod, I can easily check that too!).

I will still need to figure out how the numbers on the adjustment dials in the app actually correlate to ANYTHING (they are "unit-less"). (They kind of remind me of the amplifier dials in Spinal Tap that "go to 11!") However, there is not much point in doing this until I have some way to quantify exactly what I'm hearing so I can then calculate how I'ld like to change it. If I can figure out what I'm hearing then I should be able to figure out specifically how those "unit-less" adjustments effect the exhaust note. (Even if it ends up being by trial and error)

I'm looking forward to this little challenge. ...and, Yeah, the winters ARE pretty long here in Wisconsin... ;-)

Last edited by evanevery; 01-05-2019 at 04:30 PM..
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      01-06-2019, 04:08 AM   #91
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I've got The Maserati module, and I've not noticed any clash between that and the internal sound really. Although, given the detail in your post you've arguably got more attuned ears than me!

One oddity I have noticed is that in "Comfort" mode the Maxhaust system with idle even when the ICE isn't active.

I've created four profiles essentially. In edrive there's no sound from the Maxhaust (as default), I've also disabled all sound for Eco-pro, then low background sound from Maxhaust for Comfort (it's there but not too intrusive) with Sport being full whack. Tends to work quite well with my driving styles and still allows me to run nearly silent when needed (edrive or eco-pro if I don't have enough battery power left).
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      01-06-2019, 10:45 AM   #92
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There are two default profiles provided for the i8. "BMW i8 2013+" and "BMW i8 2013+ (Onhe Hybrid Mode)".

- If you choose the "BMW i8 2013+" profile you will get External Exhaust sound even when the ICE isn't running.

- If you choose the "BMW i8 2013+ (Onhe Hybrid Mode)" profile you will only get exhaust sound when the ICE is running.

The primary problem (with the i8 implementation) is that if you don't pick the right mode to start with you can never effectively dial it in. Since there is an "IDLE" setting, all that happens (with the "wrong" config) is that the external sound plays the defined idle sound (when the ice is NOT running). IOW, You can effectively set what you want the car to sound like "at idle", but only the "Ohne Hybrid" mode is smart enough to completely shut OFF the sound when the ICE is not running (and not just play the idle sound). Most of my playing around has been with the Maxhaust sound module so you might want to confirm this. (I also had some firmware issues along the way). It would also be really interesting to plug in a wireless OBD monitor to see how data (RPM) changes on the CANBUS as the ICE turns on/off. This is, after all, one of the things that Maxhaust is monitoring (also Sport/ECO/Comfort mode changes).

As I now have the Maserati module as well (and my connector "upgrade" also allows me to easily re-enable the BMW factory sound), I will revisit ALL of this when I get my sound samples to analyze. I expect to learn a bunch along the way and help eliminate some of my subjectivity via digital analysis. I'm sharing all of this in case other folks want to "play along" (thank you), but I'm pretty sure my next step has to be to get some sound samples to help avoid (my) speculation...

Remember, a lot of what you are hearing in the cabin of the i8 is the internally generated sound - not the externally emulated sound. Even without my "connector upgrade", you should be able to get an idea of just how overwhelming the BMW internal sound is just by unplugging the MIDDLE connector in the Maxhaust harness. (This will eliminate ALL externally emulated sound) Do that and drive around a bit. Your car will still sound great but its all from the inside. How much difference do YOU hear when you plug the middle connector back in? Can you easily hear the external sound? How much difference do you hear?

Its all well and good for the driver to be happy with the sound inside the car. But isn't the whole point of the upgraded Maxhaust sound kit to upgrade the sound OUTSIDE the car? The question is, how well can you hear the external sound from inside the car? I have to kinda work to mentally separate the two and I think we might be able to do better by making a few adjustments. What does that car driving along side you hear?

In actuality, my hearing really isn't all that good (just ask my Wife). Maybe its specifically BECAUSE of my aging hearing that I'm being so fussy about all this. (Maybe its also because I have nothing better to do during the long Wisconsin Winter...) In any case, I think it does takes a bit of work to selectively evaluate (discriminate) the external sound while driving the i8 as the internal emulated sound is so prevalent.

I just want my i8 to sound just as great on the outside as it does on the inside!

Last edited by evanevery; 01-06-2019 at 11:23 AM..
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      01-07-2019, 03:49 PM   #93
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Well, I wanted to get the samples today but its raining here. (Yes, Wisconsin, RAIN in the dead of Winter... Who would have thought?)

Hopefully I'll get a chance to get these sound samples in the next couple of days (otherwise I've got several days of travel coming up this weekend...)
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      01-10-2019, 01:59 PM   #94
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I moved my i8 from the house to the office garage to swap cars for a weekend trip. I decided to grab a quick sound sample along the way. Unfortunately, I forgot to turn-on auto-leveling for the recording level. I got enough to get a quick sample for analysis but not good enough to post as a sample for a fair evaluation.

This clearly needs to be done properly later but here are a couple of things I noted (I had the Maserati Sound Module in place):

- I mounted my Tascam DR-05 recorder to a blank region of my license plate using a suction cup RAM mount (with an improvised safety strap running into the trunk). I oriented the recording mikes downward below the license plate. I think this is a pretty good mounting position to get a good a high fidelity sample of the exhaust sound. (Too bad I didn't set up my recorder optimally...)

- It was a short trip on side roads. I worked to establish a major section of the drive steady at 4000 RPM and another steady at 2000 RPM (as displayed on the tach).

- I then loaded the captured wav file into an editor (Audacity) and isolated and extracted a solid region for both those RPM's.

- The sound is pretty unimpressive when you hear it from the outside. The idle is better than the sound when moving. (Remember, when you are driving you are mostly hearing the BMW interior sound). I'm hoping it sounds better when I get the recording level set properly...

- I loaded each of those individual regions into a Software Spectrum Analyzer (WaveSpectra) to see what they looked like.

- At 4000 RPM, the dominant frequency appears to be 226 Hz. If my prior assumptions for 4 cyl exhaust sound are correct (Cyl * RPM / 120 = Hz), this would equate to:
  • a 6.78 Cyl engine at exactly 4000 RPM
  • a 6 Cyl engine at 4520 RPM
  • a 8 Cyl engine at 3390 RPM

- At 2000 RPM, the dominant frequency appears to be 118 Hz. This one jumps around a bit more which may be due to the relatively low exhaust sound level mixing with more prominent ambient sounds (road noise). Again, if my assumptions are correct, this would equate to:
  • a 7.08 Cyl engine at exactly 2000 RPM
  • a 6 Cyl engine at 2360 RPM
  • a 8 Cyl engine at 1770 RPM

- So its not tracking the RPM as a steady multiple, but its close! Its also clear I need to get better samples (particularly for the relatively low volume of the 2K RPM test) but that will have to wait until I get back from my trip this weekend...
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      01-12-2019, 05:43 PM   #95
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Thanks for the tip on the "Hybrid mode" option. I've changed to that and it's much better thanks. If left at the default full volume it sounds pretty jarring when in Comfort mode as the ICE turns on and off. I've lowered it down and I get a nice rumble without it being overbearing. If I want it "full on" I get that with Sport mode. Really happy with this setup!
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      02-26-2019, 07:21 PM   #96
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I am not able to view the external sound video. It says try signing in with a google apps account? Is there a way to make that video public
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      02-26-2019, 07:35 PM   #97
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FOr anyone else that needs one, let me know. Glad we now have all options out there to get these to work every way possible.
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      08-13-2019, 02:39 PM   #98
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Could you PM me the contact info to buy the Maserati sound module?
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