M4 Audio Upgrade

[RocketBoots]

I thought I'd share my M4 audio upgrade. The car is amazing; the audio, not so much. The realism, clarity, warmth, impact, etc etc were just not there. And the soundstage was at the level of your crotch. I sought to remedy those shortcomings. Having done a number of systems over the years, I like working on BMW's audio. I thought about going crazy and doing some custom fabrication, but laziness got the better of me.

Most of these modern cars require the use of the factory head unit because so much is integrated with other functions. The M4 is no exception. I replaced the factory speakers and amp for a fully active 4-way system.

The factory signal in the trunk was tapped using a Technic harness. This gave RCA outs, which fed a Helix P SIX MK2 DSP/Amp. The Helix fit snugly into the OEM amp location.




The Helix is a 6 chan amp which outputs 120 RMS x 6, and has an RCA line level out, to feed signal to another amp, thus giving 8 fully processed channels. The Helix powered the front tweeters, mids, and underseat midbass.
The factory wiring was used for the tweeters, which were PHD AF1.cTW. They dropped in to the factory sail panels nicely, and have a polished aluminum housing which can be seen through the grill.



A new set of wires were run into the doors for the midranges, which were PHD Studio Mids. With a simple adapter, the mids drop right in. They are the perfect depth.





For the underseats, the Jehnert XE200 midbass was used. Once again, with the provided custom spacer, they drop right in.



Sub-bass duty was handled by a pair of Dynaudio MW182 woofers/subwoofers mounted to the rear deck in an IB configuration using a custom baffle, and powered by two bridged channels of a Mosconi AS100.4 amp.



All of the signal processing was handled by the P SIX: Tuning, setting the crossovers, slopes, phase, time alignment, EQ. The Helix P SIX is an amazing unit. It's a Class D amp that sounds as good or better than Class A/B; I had to hear it to believe it. And it's a powerhouse to boot!

I don't like untidy wires hanging around, so I routed a USB extension under the iDrive center trim to the cupholder area, drilled a small hole in between the cupholders, and made a USB outlet to connect my phone.



Overall, this is the best system I've done. It has a certain level of realism and pulls off the trick of making the confined space of the cabin seem larger. Transparent and detailed without any harshness or fatigue. The soundstage is solidly at the edge of the windshield/powerdome, can get wider than the A-pillars and as high as the rear view mirror. Everything sounds like it's coming from in front of you, and has impact. The Dynaudio's could be considered a woofer, not a subwoofer, by most, but they hit hard and deep enough that they function as subwoofers for me. I do not prefer the kind of bass you hear a block a way. The Dyns are tight, fast, accurate, especially in the IB configuration. The Jehnert midbasses are wonderful. They handle the critical lower midrange/midbass with accuracy and speed, play high enough to blend well with the midrange and low enough to blend with the subwoofer. IMO, they're the best underseat solution to date. The PHD midrange and tweeter are excellent; very natural and detailed without harshness or fatigue. The drivers and amp have a great synergy; they match well together. The system sounds very different than stock. And last but not least, a huge thanks goes out to Don Amann of Unexpected Creations for providing me with awesome gear, service, and advice. If you're looking to upgrade your audio, he's the best.

[Mandi90TT]

Nicely done

[jaybird124]

Originally Posted by RocketBoots

I thought I'd share my M4 audio upgrade. The car is amazing; the audio, not so much. The realism, clarity, warmth, impact, etc etc were just not there. And the soundstage was at the level of your crotch. I sought to remedy those shortcomings. Having done a number of systems over the years, I like working on BMW's audio. I thought about going crazy and doing some custom fabrication, but laziness got the better of me.

Most of these modern cars require the use of the factory head unit because so much is integrated with other functions. The M4 is no exception. I replaced the factory speakers and amp for a fully active 4-way system.

The factory signal in the trunk was tapped using a Technic harness. This gave RCA outs, which fed a Helix P SIX MK2 DSP/Amp. The Helix fit snugly into the OEM amp location.




The Helix is a 6 chan amp which outputs 120 RMS x 6, and has an RCA line level out, to feed signal to another amp, thus giving 8 fully processed channels. The Helix powered the front tweeters, mids, and underseat midbass.
The factory wiring was used for the tweeters, which were PHD AF1.cTW. They dropped in to the factory sail panels nicely, and have a polished aluminum housing which can be seen through the grill.



A new set of wires were run into the doors for the midranges, which were PHD Studio Mids. With a simple adapter, the mids drop right in. They are the perfect depth.





For the underseats, the Jehnert XE200 midbass was used. Once again, with the provided custom spacer, they drop right in.



Sub-bass duty was handled by a pair of Dynaudio MW182 woofers/subwoofers mounted to the rear deck in an IB configuration using a custom baffle, and powered by two bridged channels of a Mosconi AS100.4 amp.



All of the signal processing was handled by the P SIX: Tuning, setting the crossovers, slopes, phase, time alignment, EQ. The Helix P SIX is an amazing unit. It's a Class D amp that sounds as good or better than Class A/B; I had to hear it to believe it. And it's a powerhouse to boot!

I don't like untidy wires hanging around, so I routed a USB extension under the iDrive center trim to the cupholder area, drilled a small hole in between the cupholders, and made a USB outlet to connect my phone.



Overall, this is the best system I've done. It has a certain level of realism and pulls off the trick of making the confined space of the cabin seem larger. Transparent and detailed without any harshness or fatigue. The soundstage is solidly at the edge of the windshield/powerdome, can get wider than the A-pillars and as high as the rear view mirror. Everything sounds like it's coming from in front of you, and has impact. The Dynaudio's could be considered a woofer, not a subwoofer, by most, but they hit hard and deep enough that they function as subwoofers for me. I do not prefer the kind of bass you hear a block a way. The Dyns are tight, fast, accurate, especially in the IB configuration. The Jehnert midbasses are wonderful. They handle the critical lower midrange/midbass with accuracy and speed, play high enough to blend well with the midrange and low enough to blend with the subwoofer. IMO, they're the best underseat solution to date. The PHD midrange and tweeter are excellent; very natural and detailed without harshness or fatigue. The drivers and amp have a great synergy; they match well together. The system very sounds different than stock. And last but not least, a huge thanks goes out to Don Amann of Unexpected Creations for providing me with awesome gear, service, and advice. If you're looking to upgrade your audio, he's the best.

Looks great and must sounds fantastic! How much does a system like that cost, parts and labor respectively?

[RocketBoots]

Originally Posted by jaybird124

Looks great and must sounds fantastic! How much does a system like that cost, parts and labor respectively?

The total cost is a bit difficult to accurately say, since I did the install myself. All of the adapters and baffle were custom made to be plug/play by Don, but still required a good amount of labor. I'd say if you were going to have a shop do everything, it'd be in the range of a full Akra Evo

[jaybird124]

Originally Posted by RocketBoots

The total cost is a bit difficult to accurately say, since I did the install myself. All of the adapters and baffle were custom made to be plug/play by Don, but still required a good amount of labor. I'd say if you were going to have a shop do everything, it'd be in the range of a full Akra Evo

Eesh! I presume the system itself is the cost of an akra slip on? Lol

[RocketBoots]

The gear itself is a bit more, I'd say. The install was fairly easy, except for two things: Running new wires into the doors, which was a PITA, but not too hard; and prepping the rear deck with extensive sound deadening and mounting the baffle.

For me, I also installed my rear view cam at the same time, so it was like killing two birds with one stone.

[Mandi90TT]

I ran new wires into the doors on my previous car (G35 coupe) and that was a PITA, but it was necessary, as I was bi-amping the speakers in there. Not sure I would go to the trouble on the M, but you definitely did go work doing it.

[wkndracr]

Nice build. I went with a Mobridge MOST interface and just installed a JL Audio TWK processor, replacing my old BitOne. I have an old Soundstream Reference running Morel mids and tweets, and the stock H/K underseat woofers and a JL XD 600/1 running a JL 10W6 in a Musicar style enclosure. Did you cut any metal for the sub enclosure? I like that setup. I had a pair of IB Kicker 12“ in a 1980 Cadillac about 23 years ago.

[RocketBoots]

Originally Posted by wkndracr

Nice build. I went with a Mobridge MOST interface and just installed a JL Audio TWK processor, replacing my old BitOne. I have an old Soundstream Reference running Morel mids and tweets, and the stock H/K underseat woofers and a JL XD 600/1 running a JL 10W6 in a Musicar style enclosure. Did you cut any metal for the sub enclosure? I like that setup. I had a pair of IB Kicker 12“ in a 1980 Cadillac about 23 years ago.

That's a pretty nice set-up yourself Ahh, the old Soundstream Reference. I miss that old school stuff. I was all set to get some nice A/B amplification, but the P SIX honestly sounded as good and better on some things, at 1/5th to 1/10th the size, it was a no-brainer. The rear deck on the M4 is pretty big, and had holes in it already (weight savings? ), but I did have to cut a tiny bit. It was worth it to go IB though; as you know, the trunk is pretty well sealed in these cars, so why not work WITH it instead of against it?

[wkndracr]

Originally Posted by RocketBoots

That's a pretty nice set-up yourself Ahh, the old Soundstream Reference. I miss that old school stuff. I was all set to get some nice A/B amplification, but the P SIX honestly sounded as good and better on some things, at 1/5th to 1/10th the size, it was a no-brainer. The rear deck on the M4 is pretty big, and had holes in it already (weight savings? ), but I did have to cut a tiny bit. It was worth it to go IB though; as you know, the trunk is pretty well sealed in these cars, so why not work WITH it instead of against it?

Good point on the IB setup. Too bad we're not local, I'd love to hear it. I'm a fan of A/B amplifiers (or even better, tubes!) but I agree that the newer stuff has come a long way. I've installed some of the Arc Audio class G/H amplifiers and am really impressed. Even the Hertz HDP Class D in my Miata sounds good to me.

[RocketBoots]

Originally Posted by wkndracr

Good point on the IB setup. Too bad we're not local, I'd love to hear it. I'm a fan of A/B amplifiers (or even better, tubes!) but I agree that the newer stuff has come a long way. I've installed some of the Arc Audio class G/H amplifiers and am really impressed. Even the Hertz HDP Class D in my Miata sounds good to me.

Oh yes, the tubes! I dreamed of doing some Milberts, but practicality really took over. I did an install with the Arc before, and while I thought they were decent, the Helix P SIX really is a step up. They kicked out my Mosconi AS Class D really has come a long way, even from a couple of years ago. It is too bad we're not local. I like hearing other cars.

[Tomahawk]

Originally Posted by RocketBoots

That's a pretty nice set-up yourself Ahh, the old Soundstream Reference. I miss that old school stuff. I was all set to get some nice A/B amplification, but the P SIX honestly sounded as good and better on some things, at 1/5th to 1/10th the size, it was a no-brainer. The rear deck on the M4 is pretty big, and had holes in it already (weight savings? ), but I did have to cut a tiny bit. It was worth it to go IB though; as you know, the trunk is pretty well sealed in these cars, so why not work WITH it instead of against it?

How much/what did you cut? i am coming out of 328 into M3ZCP and have been wanting to do an IB instal for awhile. If I can avoid cutting, that would be ideal. Have 2 Image Dynamics ready to go.

[RocketBoots]

Originally Posted by Tomahawk

How much/what did you cut? i am coming out of 328 into M3ZCP and have been wanting to do an IB instal for awhile. If I can avoid cutting, that would be ideal. Have 2 Image Dynamics ready to go.

The M3 is a bit of a different animal. The rear deck is not nearly as big and accommodating, so not sure what or how much you'd have to cut, and how big you can go for the size of the subs. The M4 already had some rather large holes in the deck (weight savings?? ); I just made those holes a little bigger. Hard to explain without a pic; I'll try to find one later. I was a bit hesitant about cutting at first, but it really has no effect on anything on the car (structural integrity, vibrations, etc). It's completely covered up by the baffle. It's definitely possible for the M3 though. I got the idea from a forum member's M3 that Don did.

[435MSport6Speed]

Nice system. Love the subs out back.

[sparkymarky]

Have you got any pics of those holes you cut? Is the face of the sub mounted underside of the shelf as opposed to it being sat ontop of the shelf?

Thanks as i am considering doing this so any help would be really appreciated....

[sparkymarky]

Ps. I've just been, climbed into the trunk/boot and saw the large holes i guess you refer too. They measure about 8 inches long and 3 and a half inches wide. 2 of them i saw with some metal in between the pair.....?

[sparkymarky]

Oh and something in the back of my mind about needing a free to air sub for this type of application where a sub isnt housed with a box? Or is my brain i talking horsesh*t there?

[mtr3s]

How does this compare with BavSound and BimmerTech? I currently have HK and thinking about upgrades.

[RocketBoots]

Originally Posted by sparkymarky

Have you got any pics of those holes you cut? Is the face of the sub mounted underside of the shelf as opposed to it being sat ontop of the shelf?

I don't have any pics of the holes after a small amount of trimming. You are essentially just expanding the existing holes a bit. Correct, the subs are bottom mounted.

Originally Posted by sparkymarky

Ps. I've just been, climbed into the trunk/boot and saw the large holes i guess you refer too. They measure about 8 inches long and 3 and a half inches wide. 2 of them i saw with some metal in between the pair.....?

Originally Posted by sparkymarky

Oh and something in the back of my mind about needing a free to air sub for this type of application where a sub isnt housed with a box? Or is my brain i talking horsesh*t there?

Yes, you will need a sub that works well in a free-air or infinite baffle (IB) configuration, where the sub isn't housed in a box. Keep in mind, the subs I used are quite ideal for this situation. They are pretty shallow, work well in free-air configurations, are relatively light weight, and hit hard and fast.

[RocketBoots]

Originally Posted by mtr3s

How does this compare with BavSound and BimmerTech? I currently have HK and thinking about upgrades.

Bavsound + BimmerTech should be a nice upgrade over the stock HK. The system I installed is in a whole other league. But it also costs a lot more, and required more effort to install.

[sparkymarky]

Thanks rocket boots!

Ok trying to figure out how to make a baffle.....any help?

Q.1 Did you just cut away enough metal so that ALL of the face of the sub had free space above it? I.e no metal above above it? Or was there not a clear line of sight upwards through the shelf into the cabin?

Q.2 did you then cut a hole into the shelf itself?
Looks like theres some sound deadening and the black plastic shelf above these holes? Again, did you cut through them to give the sub face a clear 'view' into the cabin ceiling/rear window?

Sorry just trying to figure out how to work with the boot and cabin rather than against it, like you quite cleverly put it in your post.
Likely i'll use the same subs you did maybe in conjunction with jehnert xe200 underseats.

[RocketBoots]

Originally Posted by sparkymarky

Thanks rocket boots!

Ok trying to figure out how to make a baffle.....any help?

Q.1 Did you just cut away enough metal so that ALL of the face of the sub had free space above it? I.e no metal above above it? Or was there not a clear line of sight upwards through the shelf into the cabin?

Q.2 did you then cut a hole into the shelf itself?
Looks like theres some sound deadening and the black plastic shelf above these holes? Again, did you cut through them to give the sub face a clear 'view' into the cabin ceiling/rear window?

Sorry just trying to figure out how to work with the boot and cabin rather than against it, like you quite cleverly put it in your post.
Likely i'll use the same subs you did maybe in conjunction with jehnert xe200 underseats.

1. Yes, mostly.
2. The black 'shelf' is the baffle. It's made out of wood. Yes, there are holes in the baffle. The subs are mounted on the baffle.

Where are you located?