Mercedes SLK World banner

1 - 11 of 11 Posts

·
Registered
Joined
·
133 Posts
Discussion Starter #1
As many of you know I replaced my head unit a while back and at the same time ended up replacing the factory HK amp with a 4 channel pioneer amp. The factory HK speakers sound pretty good, but I consider myself an audiophile so I found myself wanting more, something with better vocals and power handling.

Here is how I upgraded the speakers in my previously HK system. My goal was to add top quality drivers and also add some sound deadening to the inside of the doors. I looked all over to find a shallow 8" driver that would fit in the doors. As far as I could find, the Hertz Space 8 driver was one of the only drivers that could fit in the factory speaker pods. The problem is, they haven't made these drivers for quite a few years, so they are nowhere to be found. That had me wondering, could I fit another relatively shallow driver in these pods. The answer is YES!... with a few relatively minor modifications. Here are the speakers I ended up purchasing for this project:

Hertz Mille Pro MP 25.3 Tweeters - $160
Hertz Mille Pro MP 70.3 3" midrange - $250
Audison AP 8 shallow drivers- $200
Hertz Mille MPCX 2 TM.3 - 2-way crossover- $70

Problem #1- The factory Harman Kardon speaker pods are not made for aftermarket speakers. The HK pods are molded differently and really only able to house the factory speakers. So I just removed these pods and saved them in case I sell the car someday.
Solution: I needed to find the Audio 20 speaker pods. Luckily I found a member who was selling them and secured a pair for $50. If you do this mod, you have to have a pair of the Audio 20 pods.

Step 1. Removing the old speakers from the factory pods. The Audio 20 speakers are siliconed into the speaker pods which is about the only way you can secure a speaker into these odd plastic housings. I will say the factory Audio 20 speakers may be the cheapest pieces of crap I have ever seen. They are literally made of plastic, even the cage around the woofer! The magnets just fall off of the cage. If you have these it is only a matter of time before they fall apart I would guess. To remove the speakers I used a small prying tool under the edge of the speaker. If you pry it up a little and then work your way around, the silicone releases pretty easily. The 3" speaker is a bit harder. I used a xacto knife to cut around the outside perimeter of the speaker on the top and bottom. I also removed the silicone that is sealing 3 plastic tabs that help hold the speaker in. Then I used the pry tool on the underside of the speaker. With a little work the speaker will break loose. The speaker removes out the backside of the pod. Don't worry if you break the plastic tabs, you don't need them for the rest of the install.

Step 2. Modify the pods. You need to mod the speaker pods a little to accept the new speakers. For the new Audison driver to fit you need to cut out about a 1/4" of material to let the magnet clear the front of the housing. You can see the small amount of cutting I did on the picture below. Then for the 3" cutout there is a plastic tab on the front side of the speaker hole that you have to shave off. If you don't shave this off then the speaker will not sit down flush into the 3" hole.
IMG_2960 by James Nichols, on Flickr
IMG_2961 by James Nichols, on Flickr

Step 3. Mount the speakers in the pods. I used black silicon RTV to mount the speakers in the pods. This seems to be the most similar compound to what was used in the factory setting. Just run a bead of the silicone where the woofer mounts and drop it in. You do the same with the 3 in speaker. You have to push a bit to get the 3 inch speaker in, but it does fit. Make sure you seal up the holes left behind from the plastic mounting tabs on both drivers. I also sealed up the mounting holes where you would normally place screws for both drivers. Once the sealant cured it seemed to hold both speakers quite firmly. THe 8" speaker is basically clamped between the pod and the door so it won't be able to loosen easily due to this type of mount.
8" speaker sealed into place
IMG_2962 by James Nichols, on Flickr
Both speakers sealed into place and all holes sealed
IMG_2963 by James Nichols, on Flickr
Here is a view of how much the new driver sticks out of the factory pod. It is flush with the top, but out slightly at the bottom. The good news is there is about a half inch of room between the door panel grill and that part of the pod so when mounted the driver does not touch the speaker grill.
IMG_2964 by James Nichols, on Flickr

Step 4: Test fit the new pod. The door panel fit over the new pod, but I noticed that the door panel had a very small sliver that rested against the bottom of the 8" driver. Looking at the door panel backside, it looked like I could just shave a little off of one side of the back of the door to allow the speaker magnet to be clear. I marked off an arc from about a half inch above the Harman Kardon emblem to about 2 inches below it. (basically you are just making a spot for the magnet so just use the magnet size as you guide for how much to cut out. The backside of the door panel is basically a cardboard like substance with some foam under it. I found it pretty easy to cut this small area out with a few passes of my xacto knife. Test fitted the door again and it worked perfectly. The speaker magnet is now not making contact with any part of the door panel or grill.
Test fitting pod
IMG_2965 by James Nichols, on Flickr
Trim the back side of door to allow speaker magnet to clear. It is about a 1/4" of trimming at the center of the arc. The part I cut is on the right side of the grill in the picture.
IMG_2967 by James Nichols, on Flickr

Step 5: Run speaker cables and mount the tweeter. Since I have an aftermarket amp and I am using a 2 way crossover for the 3" and tweeter I ran 3 wires to each door. Running the wires is actually really easy. Just reach inside the door and you can poke the wires through the factory plastic boot. I mounted the tweeters to the sail shaped pieces in the same spot as the factory tweeters. They just barely fit back in place due to a wire going to the mirror, but they do fit.
IMG_2970 by James Nichols, on Flickr

Step 6: Add sound dampening. You don't have to do this step, but I do think it helps everything sound a little better and resonate less. I added a dynamat like 80mil sheet to several parts of the door. I covered the outside of the door below the factory sound deadening and then covered the flat areas of the inside door frame where I could. You don't need to cover everything to change the resonance of these panels and improve your sound. Make sure you reattach the grey foam door cover after putting the dynamat on.
Here is one strip I applied to the inside of the door.
IMG_2969 by James Nichols, on Flickr

Continue in next post
 

·
Registered
Joined
·
133 Posts
Discussion Starter #2
Step 7: wire up the pods. I wired the two speaker in the pods with their own wires and butt splice ends. I then put butt splice ends on the speaker wires I ran to the doors. That way I can remove it later easily if I want. I then used fabric tape to tape up the factory speaker wire connectors so they wouldn't rattle. I left them in place so I could hook up the old factory speakers later if I wanted.
Hook up the speaker wires to the crossovers and the crossovers to the amp, then hook up the 8" speakers directly to the amp. I am running a high pass filter in the amp to cut the low frequencies from the 3" which essentially makes it's signal band pass because the high frequencies are cut by the passive crossover. I then used a low pass filter in the amp to cut out all the high frequencies from the 8" woofers. IMPORTANT**** YOU WIRE THE 8" WOOFERS OUT OF PHASE FROM THE OTHER SPEAKERS BECAUSE THEY ARE MOUNTED BACKWARDS IN THE DOOR. All you do is hook up the negative to the positive terminal and positive to the negative terminal for the two woofers. This puts them in phase with the other 2 speakers since the woofer is mounted with its face inward.
Next, Test everything to make sure all speakers are working and start putting everything back together.

First Impressions. The new tweeters are a huge improvement over the factory HK tweeters and really bring the soundstage up from the floor. The vocals are quite a bit more accurate and natural sounding. The bass sounds about the same from the Audison speakers but is very clean even at high volume. The factory HK 8" speakers actually sound pretty good. It's the other 2 speakers that I really felt were lacking. Overall, I am very pleased with this set up now. This sounds quite good at all volume levels and I do not have any rattles or other sounds due to the installation. This takes a little bit of modification, but unless you open the door panels and looked really closely you would never know that something was different. Hope this helps others who would like better sound. If you have HK its a noticeable improvement. If you have the Audio 20, I would imagine this is a night and day difference! I also added the subwoofer between the rear seats which helps to fill in the bottom end as well.
 

·
Registered
Joined
·
3,363 Posts
Thank you for the thorough and well documented mod. One of the issues that a lot of members have is the sound system in the car, while it’s very good for a factory sound system - has room for improvement.
 

·
Registered
Joined
·
762 Posts
Nice write up! Any plans to add a subwoofer? I agree the mids and highs need some help in the HK system, but they aren't horrible. The 8" do a fine job as a midbass, but they really fall off hard after 50hz (especially with the top down). Any reason you went with Hertz, or just preference? I will probably be tackling this in a year or so.
 

·
Registered
Joined
·
133 Posts
Discussion Starter #6
Nice write up! Any plans to add a subwoofer? I agree the mids and highs need some help in the HK system, but they aren't horrible. The 8" do a fine job as a midbass, but they really fall off hard after 50hz (especially with the top down). Any reason you went with Hertz, or just preference? I will probably be tackling this in a year or so.
Yes, As I mentioned, I replaced the rear vertical console with a compact subwoofer from Alpine. It adds a lot of low end and keeps a relatively low key factory look. I'd still like a little more bass, but I don't want the rattles that come with a trunk mounted sub.
 

·
Premium Member
Joined
·
105 Posts
A man with taste! Just upgraded my R172 with Mille Pro 3 ways from Audio 20 - wasn't going to add a sub (added an Audison AP8.9 bit amp) but succumbed and fitted my old 10" Rockford from my C class in a spare wheel sized housing. Almost finished, just added optical in and the DRC remote but need to find a better way of mounting the sub.
 

·
Registered
Joined
·
762 Posts
Yes, As I mentioned, I replaced the rear vertical console with a compact subwoofer from Alpine. It adds a lot of low end and keeps a relatively low key factory look. I'd still like a little more bass, but I don't want the rattles that come with a trunk mounted sub.
Ahh, I missed the last line. Which one did you go with? I am leaning towards a shallow mount 12" in the rear bulkhead if I can find some room. I will open it up at some point to see if there is any hidden space in there. I agree that I don't want a trunk mounted sub. I drove an SLK with two 12's in the back and it had the bump, but you could tell it wasn't open to the cabin. It lost a lot of fidelity.
 

·
Premium Member
Joined
·
190 Posts
Yes, As I mentioned, I replaced the rear vertical console with a compact subwoofer from Alpine. It adds a lot of low end and keeps a relatively low key factory look. I'd still like a little more bass, but I don't want the rattles that come with a trunk mounted sub.
I have seen this in an installation before....
https://www.crutchfield.com/p_777B8PTD/Sound-Ordnance-B-8PTD.html

Between the seats also in place of the vertical console.
I cannot comment on its performance.
 

·
Registered
Joined
·
133 Posts
Discussion Starter #10
I went with this Alpine sub. It actually sounds pretty good for a compact 8". Certainly more than the door speakers. If you have shorter legs like me, you could fit another one of these or maybe a really shallow 10" behind the seats. I think anything bigger would be hard unless you move the passenger seat way up. The other option is to move the amp to the trunk and stick a shallow 10" in the passenger footwell with a grill over it.
https://www.crutchfield.com/p_500PWES8/Alpine-PWE-S8.html?tp=114

Here is my post that shows how I mounted the sub in the car. Looks pretty nice I think.
http://www.slkworld.com/slk-r171-general-discussion/464353-install-pioneer-2330nex-amp-replace-harman-kardon.html
 
1 - 11 of 11 Posts
Top