When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Over the past few months, I've done a lot of experimenting and tinkering with my 958.2's factory Bose system to try to make little improvements here and there. As with most car related mini-projects, this spiraled into a much larger and more expensive end result. But there were some valuable things I learned about the platform, more advanced car audio in general, and especially the main deficiencies/challenges the Bose system presents for anyone looking to get more out of it. I'd like to share my upgrades as well as my reasoning for why I went in certain directions that I did as opposed to other roads that may have been taken before.
For a main summary of what I've learned: There is no way to make one small upgrade/fix to the Bose system that will truly satisfy the ears of anyone truly displeased with the system as a whole, and especially not if you're like me and found it to be very fatiguing to listen to. Considering I spend 2 hours daily in my Cayenne for my work commute, having an audio system that is at the very least comfortable and pleasing to my ears is pretty important. Since OEM audio integration systems like those from Bose typically use cheap components with built in signal processing to correct at the amp, just simply replacing components isn't always going to provide a better sound.
Now into the details!
I started off this journey at the tweeters. There's been a somewhat popular thread over the years as a small upgrade for the Bose system that involves replacing the factory tweeter with one from a Ferrari that supposedly gave some improvement, albeit quite small. But it's a relatively inexpensive option and appears to be truly plug and play. Not a whole lot of downside there. I decided I needed a more notable improvement than what was discussed in that thread, and I decided a good set of aftermarket tweeters were going to be a better use of my dollars. I didn't want to go crazy on it yet, so I eventually decided to purchase a set of Audiofrog GS10 tweeters and some basic Crutchfield 5kHz -6dB/oct high pass filters, or "bass blockers." After installing these, they brightened up the highs of the system quite a lot. They were some of the most detailed tweeters I've heard in a long time... yet I could not get them to play nicely with the rest of the system in the slightest over the month I had them. The system as a whole had gone from being fatiguing to be downright painful at times.
I could tell that the tweeters themselves were not really the sole cause of the now painful audio system. It was apparent that they just didn't mesh with the factory Bose components in a manner that a "plug and play upgrade" would. This led me to replacing the center channel with an Audiofrog GS25 (which I have another thread on). This finally made a true improvement in clarity and reduced some of the fatigue the system presented, especially from vocals. But it still wasn't enough, and it made it apparent that the real issue I had with the Bose system was the door midrange speakers. This is the point in this journey I believe I did the most learning about the Bose system. It's also where I spent the most money because I figured out this was no longer a small project.
While sound deadening both front doors, something about the factory door cards started looking a bit familiar to me as someone who's dabbled in car audio on 3 previous BMWs: the Bose midranges have a 3 bolt speaker pattern that looked identical to my past BMW speakers. For anyone else who's had BMWs they've played with, especially audio-wise, you're aware of just how many companies market and sell plug and play BMW specific speakers e.g. Bimmertech, Bavsound, Focal, etc. The nice thing about these plug and play kits is that you didn't have to mess around with making custom mounts either with 3D printing, trimming ABS sheets, stuff like that which requires a bit more specialized of equipment that perhaps your average Joe doesn't have lying around their garage. It appears that only one company has ever tried to do that with Porsches (RennSpec), but it didn't seem like they stayed in business or in the market for much more than a year. The downside to most of these plug and play kits in the BMW world was that they weren't ever a really good value for the speaker quality you were getting. Even the Focal options were possibly based on the lowest grade speakers that Focal offered. But very recently Morel decided to join this party with multiple product line offerings, the higher of which being entirely based on their highly revered Hybrid series. This immediately intrigued me and I decided to be Crutchfield's first customer for the Morel IR-BMW42, and test it out in a Porsche!
Packing of the Morel Integration Reference BMW (Hybrid MW4 and MT250) kit was every bit as high of quality as one would expect of a brand like Morel. They were beautiful, I almost didn't want to throw the box away! Time to play around and compare to what we've got in the 958 Bose system.
Surprise! The wonderful BMW specific mount is not so specific after all! And of course, the nearly $1,000 spent on the midrange and tweeter combo would not be in vain. The Morel midranges have a deeper and more sturdy cone than the Bose, and since they have a hybrid ferrite and neodymium magnet, they're actually a lower overall profile than the Bose midranges too. Since the midranges are mounted in a shallow part of the door card, the mounting depth is a pretty important dimension for these speakers.
Test fitting them into place confirms a perfect fit. Where doing something like this will differ from the true plug and play upgrade you'd get on a BMW is with the connectors since the connectors included are meant for a BMW speaker harness. This shouldn't scare you off though not only because rewiring the included connectors to integrate into the 958 speaker harness, but also because the included BMW connectors are hilariously awful. They're so bad that even if I were performing this upgrade on a BMW, I'd probably just rewire everything with a proper harness connector or even just basic switchblades. But enough about that because interestingly enough, this isn't my biggest complaint about the Morel IR BMW kit. More on that later.
The Morel integration kit also comes with an inline low-pass filter for the midrange and high-pass filter for the tweeter, which both together create a crossover at 2200Hz with -12dB/oct roll offs. This is important not only so that the midrange and tweeter mesh well together, but for an even more important factoid I learned about the 958 (and actually most Porsche) Bose audio systems: the tweeter and front door midranges are wired to the same channel amplifier channel. Upon learning this, I realized why my prior tweeter modifications just never could produce audio that was anything short of fatiguing and painful. And after talking with some shops/experts more familiar than myself with Porsche audio, I figured out that the Bose door speakers are not actually a midrange speaker: they are full range speakers. The Bose tweeters are high-passed in a similar manner to how I added a 5kHz high-pass filter to my Audiofrog GS10 tweeter, except they're filtered at around 12kHz. This fact right here is why those who've done the Ferrari tweeter upgrade didn't hear all that much of a difference after swapping. Most people don't hear significantly hear frequencies above 14-15kHz. So with the GS10 now handling 5k-12kHz that the Bose door full range was also handling, it made for a lot of frequency interference that resulted in very harsh trebles that were entirely above the vocal range. The best way to think about how this sounded was that even at the lowest volumes, the system felt like it was too loud.
Since the Morel kit included tweeters, I figured I might as well use them and thus they replaced the Audiofrog GS10s. Since they were within Crutchfield's 60 day return window, I was able to return them for full credit (going to take a second to praise Crutchfield for always being stellar with customer service for the past 10 years at least I've been a near exclusive customer of theirs). Being that the BMW kit is meant to integrate with various locations around a modern BMW that use separate component speakers and tweeters, there's a couple of different mounts included. BMW sedans like my previous F80 M3 have tweeters on the rear deck behind the seats as well as on-axis tweeters for the front doors, so the kit includes mounts for both of these locations of course. Since our Bose (and Burmester) tweeters are upward firing dash corner speakers, the deck speaker adapters were what I opted to use. These actually tilted the tweeters maybe 20-30 degrees forward versus straight up, and I figured would give better/more linear response since we don't have the option for on-axis mounting unless custom panels are created. These also allowed me to somewhat point the tweeters towards a central point between the front headrests. Funny enough, these are held in their place with duct tape and it has actually worked perfectly.
Now at the same time I purchased the Morel midrange and tweeter kit, I also took the plunge on replacing the lower door woofers. There's not a ton of information regarding what fits the lower doors, but really that has a lot more to do with there not being any mass produced mounts for that location for easy integration. There's actually quite a lot of real estate to fit some pretty beefy woofers. As mentioned on some of the other DIY audio threads, the main restriction towards the rear of the door woofer housing is a plastic support that holds up the window track (sort of important!). But since the door card bulges out quite a bit at the woofer to make room for our large door storage area, there's a lot of real estate to take advantage of moving outward. I don't know the exact number of inches to play with since that's a tough measurement to get through the woofer grille, but I was able to measure the depth from the edge of the woofer mount to the plastic support inside, and then also measure the height that the Bose woofer protrudes and add these together to at least get a conservative range. Both of these measurements came out to around 2 inches, which means you've got 4" of depth to play with for woofer upgrades. There are a lot of 8-9" speakers that fit into this dimensional space with ease, but I chose to go with the Audiofrog GS8ND2, an 8" midbass/subwoofer.
The next thing to address: how can I actually get it to mount with the proper standoff from the door to ensure there isn't any interference with the inner door components? Well an obvious answer can be to fabricate your own mounts. I was actually able to find a seller on eBay who made 8" door woofer adapters for the 958 Cayenne out of stacked PVC, which is a great material for doors where the potential for moisture exists and is a good reason not to use something like MDF. The adapters are great quality, fit, and construction, but they're also only an inch tall. The same seller also makes a generic 8" speaker spacer which is 1/2" tall that I also purchased and used PVC cement to create a 1 1/2" tall speaker mount. This created the perfect standoff height for the GS8s. I drilled a small hole in each to route the speaker wires through, sealed the hole up on each side with silicon, added some weather seal on both mounting surfaces of the speaker adapter to full seal off the chamber, and mounted them up perfectly!
For door sound deadening, I've put Soundskins Pro inside the entire inner door and topped with Dynamat Dynaliner. These together create an impressive amount of noise dampening and if going this deep into audio upgrades really cannot be overlooked. I actually did these before upgrading a single component and they made a noticeable difference in every aspect. Bass became tighter and more controlled, road noise quieted down a little... if there's anything in this whole process that can be done all by itself without any of the rest of it, it's sound deadening. Getting back there is daunting at first, but it's not too bad.
This side-by-side of the Bose door woofer and new Audiofrog GS8 sitting in its semi-custom mount show that they protrude towards the speaker grille the exact same amount, and really could not be more perfect of a fit. Now that the entire front stage was significantly upgraded from a component standpoint, a major thing became apparent. This whole system needed more power! After lots of praise from @Flygts about mObridge in his incredible looking system, I decided to take the plunge as well.
It's amazing the level of power the mObridge 8.1.1 K2 is able to fit into a package about the same size as the factory Bose amp. 75W RMS x 6 channels at 4 ohms, 150W RMS x 2 channels at 4 ohms, 1 pre-out, and 1 subwoofer power channel good for 250W RMS at 4 ohms or 400W at 2 ohms. The high power channels power the front door woofers, and by default the rest are wired up in the same manner as the Bose channels with the front midrange and tweeter on 75W channels, rear door components on 75W channels, the center channel on it's own 75W channel, and the two rear "effect" speakers on their own 75W channel as well but both speakers on one channel since they're mono (I actually didn't realize these speakers existed until I saw the wiring diagram).
Accessing the battery and running the 4AWG power cable is certainly the toughest part of the amp upgrade, though I also needed to create a mount for it to go into the factory location. Believe it or not, this was the only part of this whole project that I had to truly fabricate. I was able to do it with some scrap aluminum from Home Depot, metal shears, and a drill bit for the mounting holes. It's not pretty or overly sturdy, but it works and that was good enough for me. Once the amplifier was in providing some real power to the speakers, they could finally sing the way they were intended to!
Though if only it were that easy I spent a couple of weeks tinkering with the mObridge DSP trying to get everything to sound perfectly, but I just couldn't do it. I have to say, trying to teach myself to tune the audio system as a whole was a far steeper learning curve than I thought it would be. I finally got to a point where I came to the conclusion that the passive crossovers between the tweeters and door midranges just weren't going to cut it. This brings me to my biggest complaint about the Morel integration speaker kit. I do not know why the 2200Hz crossover frequency was chosen for this kit, because it's frankly just an awful choice. The tweeters are very tinny sounding when they're trying to reach down into the mid-upper ranges of the vocal ranges, and the midranges just weren't allowed to really show off their warmth and detail.
This made for an easy decision that I would rewire the center channel and rear effect speakers channel so that they would power the tweeters, making for a 3-way active front stage. So now the amp has full control over every front stage speaker, and I was able to find a proper crossover frequency for this speaker set. After this, the system sounds beautiful. My final crossovers for the front stage are:
Yes, those Audiofrog GS8 speakers really do go that low.
Fraser Ryan at mObridge has been fantastic to work with throughout this whole process. Most recently to finally finish this off, he was able to jump on a call with me to remote in on my computer and show me the ropes for how to use the MiniDSP mic and REQ real time analyzer software to assist in tuning the mObridge DSP. In about an hour of a call, I'd learned so much that I was able to get my tuning to a point where I truly believe I am finished (for now ) in about 20 minutes after the call. I'd gotten to a point tuning by ear that the system as a whole was very enjoyable and sounded great, but it just felt like it was missing things in some places. I just couldn't tell where or what it was missing by ear, and now that Fraser showed me how to truly understand the real time analyzing, it became immediately apparent visually where the speakers had dips in frequency response, a couple of phase issues, and it was as easy as isolating each speaker, adding/subtracting some gain at points on the DSP where the real time response wasn't flat, and then adding it all together.
My "final" result is an audio system that feels warm, powerful, and incredibly detailed in every regard I could ask for. The Audiofrog GS8s can play deeper and with more oomph than the Bose subwoofer does, they replicate a big kick drum so well in both sound and feeling that they could be the kick drums themselves, they produce a beautiful and smooth bellow to the low notes of an acoustic guitar or bass guitar, and they give warmth and depth to the lower vocal ranges. The Morel MW4 mid ranges truly sing for almost the entire vocal range, give lots of life to an electric guitar riff, and now that they're properly crossed with the tweeters they work together to bring a very spirited and warm energy to the higher notes.
The Bose subwoofer and rear door speakers are what currently remain of the factory Bose system and I'll upgrade them in due time, but with some simply tuning of each to mesh with the front components they really do sound adequate. At least enough that I can save some money in the mean time. I believe in the future I will probably construct a custom 10" subwoofer box to either go under the spare tire like Flygts did, or just replace the spare tire altogether. Being able to fit something punchy like an Audiofrog GB10 subwoofer would be the ultimate addition to this system, but keeping the spare tire might be an attractive enough feature to just make something like a Hertz MPS 250 shallow 10" subwoofer be the best option. I'm happy enough with how the system currently sounds that I don't think I will feel the need to explore that more until next year at the very least.
You certainly don't have to go as crazy on speakers to get a serious upgrade from the Bose system, but having the mObridge DSP/amp I would certainly view as the baseline requirement. Being able to correct and properly power the front stage can bring a lot out of more cost effective speakers as well. I also do not miss the rear effect speakers or even the center channel at this point either, so wiring it for 3-way active in the front is an upgrade all in itself without any real downside. But hopefully this is more than just some pictures and word vomit to the community! And I hope this inspires anyone looking to do some upgrades with minimal fabrication.
Thanks for sharing @RhinoComp . I went down this particular path once, many years ago, before all the components talked over a local network and I just pulled stock components and stuck in ADS separates. (yea, it was that long ago...)
Most of my critical listening in the car these days is podcasts and recorded books. So...I'm going to avoid rereading the above post. It might give me ideas!
Thanks for sharing @RhinoComp . I went down this particular path once, many years ago, before all the components talked over a local network and I just pulled stock components and stuck in ADS separates. (yea, it was that long ago...)
Most of my critical listening in the car these days is podcasts and recorded books. So...I'm going to avoid rereading the above post. It might give me ideas!
I'd be lying if I said most of my daily listening wasn't podcasts as well! But for the few days or long trips that aren't podcast filled, it sure is nice to have something that sings!
Very impressive research and upgrade! I have the Burmester which I'm very happy with; I've no idea how different it is to the Bose.
However, there is one thing which is not great, and probably affects the Bose as well. The bass frequency response is very non-linear, one or more points must have a lot of resonance. This results in some music being unlistenable because the upper bass is far too boomy and obscures the midband. I had a home subwoofer that had a DSP-based calibration in it, where it would play audio sweep sounds, measure the signal through a mic and equalize the frequency response to compensate. I thought there should be a phone app which can do this for use in the car, but I haven't been able to find one...
(Example for home theatre use here https://audyssey.com/home-solutions/)
Very impressive research and upgrade! I have the Burmester which I'm very happy with; I've no idea how different it is to the Bose.
However, there is one thing which is not great, and probably affects the Bose as well. The bass frequency response is very non-linear, one or more points must have a lot of resonance. This results in some music being unlistenable because the upper bass is far too boomy and obscures the midband. I had a home subwoofer that had a DSP-based calibration in it, where it would play audio sweep sounds, measure the signal through a mic and equalize the frequency response to compensate. I thought there should be a phone app which can do this for use in the car, but I haven't been able to find one...
(Example for home theatre use here https://audyssey.com/home-solutions/)
I think the best differences between Bose and Burmester are going to be with the front stage since the Burmester is running 3 way active like I've done. With regards to the bass, the Bose is pretty similar in that regard. You've just got a 10" woofer to work with versus the 8" we get with Bose. I'm not sure if it's the factory Bose/Burmester audio processing that creates such boominess, but with the mObridge DSP I'm able to remap and tune the signal going to the Bose subwoofer to make it mesh a ton better. I think most of the issues the Bose subwoofer has are more in the 80-120Hz range which sounds like it may be similar with yours too. I got around this actually by just low passing the subwoofer somewhere in the realm of 67Hz, I haven't even tried to use any EQ on that channel. The Bose sub is actually somewhat decent in the true sub-bass range so allowing it to only get those signals improved a lot. Besides that, the 8" Audiofrogs in the doors getting 150W RMS each are also definitely the happiest around the 80Hz range from a bass standpoint. So even though they aren't low passed until 29Hz, they work really well extending down and adding to the sub-bass without making anything muddy or boomy.
For the real time analysis, I bought a miniDSP UMIK-1 calibrated mic based on the recommendation of Fraser at mObridge and just used Room EQ Wizard (free software) to actually view the RTA. It's probably not the most advanced equipment ever, but absolutely works well enough to provide a good curve for what you're hearing and the mic itself was only $120 or so. I also found playing 48KHz 16bit pink noise file to be more helpful in seeing the frequency response of the system since it plays a flat signal response across the entire frequency range. It accomplishes the same thing the Audyssey mics included with a lot of home theater AVRs like you mentioned though probably a bit more accurate hardware focus on frequency response. I think the basic Audyssey equipment is more aimed at time alignment than anything. But the miniDSP mic is certainly worth a purchase to try to identify which frequencies you're hearing that are causing distaste! I tuned my system as much as I could by ear for about two weeks straight almost daily. I got it sounding "pretty darn good," but it was just missing things I couldn't ever seem to find. The RTA with pink noise showed the dips and crests in response that I couldn't put my finger on immediately, and I was able to make the system sound near perfect it what seemed like 10 minutes from there. Not sure how much modification you're able to do with the Burmester system internally, but it's still nice to know where your issues lie!
I'll be playing with the RTA stuff soon to see what I can do with my Focal loudspeakers at home next
... showed the dips and crests in response that I couldn't put my finger on immediately, and I was able to make the system sound near perfect it what seemed like 10 minutes.
Nice, thanks! You are many steps ahead Thanks for all the extra ideas & info.
Once you had the frequency response plots from the RTA, how did you then manage to adjust the playback response to be flat? Is this configuration of your moBridge's DSP? I was thinking an app was necessary on the phone to apply the equalization during playback (assuming that it is not possible to reconfigure the DSP in the Bose/Burmester). Maybe a parametric eq app could be setup manually... The eq settings in the PCM seem too coarse to fix the resonances.
Nice, thanks! You are many steps ahead Thanks for all the extra ideas & info.
Once you had the frequency response plots from the RTA, how did you then manage to adjust the playback response to be flat? Is this configuration of your moBridge's DSP? I was thinking an app was necessary on the phone to apply the equalization during playback (assuming that it is not possible to reconfigure the DSP in the Bose/Burmester). Maybe a parametric eq app could be setup manually... The eq settings in the PCM seem too coarse to fix the resonances.
With real time analysis, I’ve got the mic placed inside the car with pink noise playing, and wires routed to the outside where I fiddle with stuff from my laptop so I don’t disturb the sound readings. With both the mic and mObridge DSP connected to my computer, I can look at the real time frequency response of the entire system (or isolate speaker by speaker in the DSP) and I can make little points on the DSP to either add or subtract gain to parts of the signal curve and adjust how steep they are as well. I’ll notice little dips or spikes in the response curve, figure out the midpoint of the anomaly, and then in real time correct that point on the DSP.
Quick example of how I’m viewing the real time frequency response in the top left window, on modifying the master EQ of the DSP in the window behind it
Now, that’s certainly not going to be something possible in the factory PCM, but if you have something like the Mr12Volt CarPlay system it also has a basic EQ that can kind of help in some areas, but it’s nowhere near what you can do with the true DSP built into the mObridge amp.
That being said! Something I forgot to mention earlier, I also have entirely sound deadened doors, and also trunk area around the subwoofer. When you talk about annoying resonances, those can also be sounds being amplified by panels vibrating or even echoing in volumes. I didn’t notice a ton out of doing the trunk area under the spare, but doing the inner doors behind the regulator and also basic deadening on the door card made a big difference in tightening up sub and mid bass coming from the doors. While a super advanced DSP isn’t accessible without an audio hardware upgrade, sound deadening is something absolutely everyone and every vehicle will benefit from. That alone made a pretty substantial difference in how livable the Bose system was before going all in. Sound deadening is always going to be the best place to start with any vehicle, in my opinion anyway. There’s also just no way for sound deadening to make something worse.
I'm starting to scout out MY17/18 e-Hybrids and hope to upgrade the stereo in a similar manner to you, so considering feasibility/cost of different options out there. Looks like the MOST150 interface makes the mObridge DSP/amp combo pretty attractive compared to the standalone fiber converters that are going for close to $1,000 USD...(good opportunity for someone to design a more budget-friendly option and undercut the two players currently selling these products?).
I have a question to clarify in your build - If I understand correctly, you ended up using two of the 75W channels for the bose rear door separates (i.e. R + L, each channel powering the woofer, mid-range, and tweeter).
Were you able to apply some sort of passive crossover network to these components? Or perhaps the rear door components already have a crossover so you only need to run positive/negative signal to each rear door?
3-way active up front seems like the way to go, but seems like overkill and unnecessary cost/complexity for the rears, so just curious how you went about tackling this part of the system.
Last edited by oslosisjones; 12-04-2023 at 01:59 AM.
Reason: typo
I'm starting to scout out MY17/18 e-Hybrids and hope to upgrade the stereo in a similar manner to you, so considering feasibility/cost of different options out there. Looks like the MOST150 interface makes the mObridge DSP/amp combo pretty attractive compared to the standalone fiber converters that are going for close to $1,000 USD...(good opportunity for someone to design a more budget-friendly option and undercut the two players currently selling these products?).
I have a question to clarify in your build - If I understand correctly, you ended up using two of the 75W channels for the bose rear door separates (i.e. R + L, each channel powering the woofer, mid-range, and tweeter).
Were you able to apply some sort of passive crossover network to these components? Or perhaps the rear door components already have a crossover so you only need to run positive/negative signal to each rear door?
3-way active up front seems like the way to go, but seems like overkill and unnecessary cost/complexity for the rears, so just curious how you went about tackling this part of the system.
One thing to keep in mind is that the MOST150 is a newer, albeit better, fiber optic technology platform that doesn’t quite have as much support. I’m not positive whether mObridge currently has something for the MOST150 vehicles, but I’d bet they’re working on it if not to market with it already.
As for the rear door, I believe it’s the same sort of capped tweeter that is in the dash corners to make a passive crossover which somewhere in the realm of a -6dB slope at 10KHz, and the 6.5” woofer is just fed full range signal. So no passive crossover is needing to be added when keeping the factory components. With the DSP, I at least high passed the whole channel to keep the sloppy bass notes away from the channel as a whole. The amp also has a dynamic channel limiting feature that I use to ensure I don’t overpower that channel since the speakers are likely really low impedance. This is the case for Bose anyway. Burmester I believe is a passive 3 way system in the rear doors to begin with, but they’re also 3 way active in the front stage already too. So I’d assume it’s an even easier thing to tackle.
As for 3 way in the front, the ideal way would be to have the guys create your wiring harness with it in mind which they delete the center channel and rear effect speakers in the D pillars (didn’t even know these were here, you won’t miss them). Then from there, run two pairs of speaker wire from the amp to the dash corners since they’re an easier location to reach without tearing stuff apart. Just the speaker cover and fuse box cover is all that’s needed to feed from the cabin area to the tweeter location and pull through. From there, I didn’t even remove any interior paneling to hide the wire. I just lifted them a little bit with the pry tool, and fed the wire underneath the entire way back to the trunk area. Super easy. Then on the amp side, it’s just as simple as identifying that channel as now being the tweeter for the appropriate side and then proceed with tuning. Being able to truly get the front stage meshed the way it needs to with each individual channel is so valuable, especially considering the up firing dash corner location does not make for a very easy thing to perfect acoustically.
Happy to help in any way I can, but also I’d highly recommend talking to the folks at mObridge like Fraser Ryan. They’re a small company and when talking with them I get the feeling they’re all just a bunch of car audio enthusiasts that also happen to be software and electrical engineers. Incredibly helpful on all fronts and Fraser even got on the phone with me for nearly an hour while remotely controlling my computer to give a crash course on tuning the channels as well as how to make sense of real time analysis. This project would’ve been a dead end road without those guys.
One thing to keep in mind is that the MOST150 is a newer, albeit better, fiber optic technology platform that doesn’t quite have as much support. I’m not positive whether mObridge currently has something for the MOST150 vehicles, but I’d bet they’re working on it if not to market with it already.
As for the rear door, I believe it’s the same sort of capped tweeter that is in the dash corners to make a passive crossover which somewhere in the realm of a -6dB slope at 10KHz, and the 6.5” woofer is just fed full range signal. So no passive crossover is needing to be added when keeping the factory components. With the DSP, I at least high passed the whole channel to keep the sloppy bass notes away from the channel as a whole. The amp also has a dynamic channel limiting feature that I use to ensure I don’t overpower that channel since the speakers are likely really low impedance. This is the case for Bose anyway. Burmester I believe is a passive 3 way system in the rear doors to begin with, but they’re also 3 way active in the front stage already too. So I’d assume it’s an even easier thing to tackle.
As for 3 way in the front, the ideal way would be to have the guys create your wiring harness with it in mind which they delete the center channel and rear effect speakers in the D pillars (didn’t even know these were here, you won’t miss them). Then from there, run two pairs of speaker wire from the amp to the dash corners since they’re an easier location to reach without tearing stuff apart. Just the speaker cover and fuse box cover is all that’s needed to feed from the cabin area to the tweeter location and pull through. From there, I didn’t even remove any interior paneling to hide the wire. I just lifted them a little bit with the pry tool, and fed the wire underneath the entire way back to the trunk area. Super easy. Then on the amp side, it’s just as simple as identifying that channel as now being the tweeter for the appropriate side and then proceed with tuning. Being able to truly get the front stage meshed the way it needs to with each individual channel is so valuable, especially considering the up firing dash corner location does not make for a very easy thing to perfect acoustically.
Happy to help in any way I can, but also I’d highly recommend talking to the folks at mObridge like Fraser Ryan. They’re a small company and when talking with them I get the feeling they’re all just a bunch of car audio enthusiasts that also happen to be software and electrical engineers. Incredibly helpful on all fronts and Fraser even got on the phone with me for nearly an hour while remotely controlling my computer to give a crash course on tuning the channels as well as how to make sense of real time analysis. This project would’ve been a dead end road without those guys.
Gotcha, yeah that makes sense. I was thinking there were 3-way components in the rear but looks like I misread. 2-way makes it easier with just a cap for the tweeter and high passing the signal like you said.
Did you end up fully deleting the center+surround speakers or just running them all off a single channel with a mono signal? Only issue I see with the latter approach would be the time-delay difference between the dashboard and rear pillar - probably would want to pick one or the other if keeping either of those.
Definitely appreciate the help and will keep the folks at mObridge in mind!
Gotcha, yeah that makes sense. I was thinking there were 3-way components in the rear but looks like I misread. 2-way makes it easier with just a cap for the tweeter and high passing the signal like you said.
Did you end up fully deleting the center+surround speakers or just running them all off a single channel with a mono signal? Only issue I see with the latter approach would be the time-delay difference between the dashboard and rear pillar - probably would want to pick one or the other if keeping either of those.
Definitely appreciate the help and will keep the folks at mObridge in mind!
For now, they’re fully deleted from a signal standpoint. Surprisingly, even the center doesn’t add enough to justify keeping it versus going 3way. 3way blows any stock configuration out of the water. But if you did want to keep the center channel, the mObridge has a preout flex channel that could be used as a subwoofer preout, but also could be used as a center channel preout to something like a small 75w mono amp. Someone else on here did that with like a Toro amp I believe and it seems to be a good solution if you’re dead set on keeping the center. This was actually what I originally planned to do (because I have a very nice Audiofrog GS25 in the center location still) but I honestly just don’t feel like I miss it at all, so I just can’t be bothered with adding another amp, powering it, and running those wires to a noncrucial channel.
Its worth mentioning that if you did want to upgrade your rear door to 3 way passive, the speaker locations and grilles are still there even on base and Bose doors, so it’s pretty easy to mount in
And yes, time alignment would be a disaster trying to get those all in phase. And is also another reason going 3 way is so helpful for the front stage. Having the tweeter and midrange on the same channel despite being 20” further away is not something you can fix easily without separating
If I'm reading your posts correctly, the GS25 center channel is not a top priority, is that correct? I've got a 2016 CD (base radio, not Bose or Burmester) and am putting together the wish list and the center channel is a question mark. Currently headed toward Morel's Carbon Nano 63's up front, Nano 62's in the rear all powered by Morel's 4/400. Center channel is up for debate as is a Sub.
Would love to hear your thoughts and or any other's input, thank you!
If I'm reading your posts correctly, the GS25 center channel is not a top priority, is that correct? I've got a 2016 CD (base radio, not Bose or Burmester) and am putting together the wish list and the center channel is a question mark. Currently headed toward Morel's Carbon Nano 63's up front, Nano 62's in the rear all powered by Morel's 4/400. Center channel is up for debate as is a Sub.
Would love to hear your thoughts and or any other's input, thank you!
I wouldn’t make it the top priority. It can certainly add to the system in the ideal scenario and it’s certainly an upgrade over stock components if you weren’t replacing the amp. But with Base radio you’ve got a bit more freedom to go crazy on DSP and amp since you don’t have to deal with the fiber optics. If it came down to prioritizing the center channel or subwoofer, I would definitely prioritize the subwoofer if that helps!
Dragonfly, the nanos are great, I run the 63’s in my rear doors. Up front I’m running the elate 93’s with a mm3 center. The center is not a must, but brings a lot of tonal balance to the front stage. I would recommend running an 8 or 9 inch mid bass in the front door since it doesn’t take any modifications. Morel has several options in that department. My sub is only playing 50 hz and down, but with the 9” woofers in the doors, I could go without a sub.
08-30-2023, 04:37 PM
958.2 Bose Audio Upgrade - mObridge, Morel, Audiofrog
I spent a couple of weeks tinkering with the mObridge DSP trying to get everything to sound perfectly, but I just couldn't do it. I have to say, trying to teach myself to tune the audio system as a whole was a far steeper learning curve than I thought it would be. I finally got to a point where I came to the conclusion that the passive crossovers between the tweeters and door midranges just weren't going to cut it. This brings me to my biggest complaint about the Morel integration speaker kit. I do not know why the 2200Hz crossover frequency was chosen for this kit, because it's frankly just an awful choice. The tweeters are very tinny sounding when they're trying to reach down into the mid-upper ranges of the vocal ranges, and the midranges just weren't allowed to really show off their warmth and detail.
Thanks for all the extra ideas & info.
