Mercedes-Benz Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
1,438 Posts
Discussion Starter #1
I know cutting a car is sacrilege, but I'm going to try to do it as neat as possible. I will do the cutting sometime tomorrow.

Strange how the speaker grills in the parcel shelf suggests 6x9 speakers :D.

Used the template that came with the box to mark the outline where I will cut the new holes with my Dremel rotary cutting tool.



 

·
Registered
Joined
·
2,742 Posts
Are you sure the rotary tool will cut that? I would think it would burn the bit up before you got all the way around it. But I will confess I'm not familiar with all the bits they have now a days.
 

·
Registered
Joined
·
1,438 Posts
Discussion Starter #3
The rotary tool uses small 37 mm diameter cutting discs. I'll probably use about two discs per hole.

I see my two holes aren't symmetrical - will fix that before I start cutting.
 

·
Registered
Joined
·
1,438 Posts
Discussion Starter #5 (Edited)
I'll see if I can take some better photos in the daylight, but here's a sound test with the 6x9 speakers installed. It makes a rather significant difference - and bass response should even be better once I install the Alpine KTP-190U mono-power pack.

Edit to add: Obviously it should be listened to with good speakers :) .

 

·
Registered
Joined
·
1,824 Posts
Actually, the reason why that back area is so big is not for 6x9 (which are a bad idea IMO). Some other models (like mine) have room for 4 6.5" speakers in the back. One of those wad for the car phone and 2 more were for the stock subs, or in the case of the bose sysm, 2 for full-range speakers, 1 for a subwoofer. I ditched my car phone speaker, and replaced it with a block of foam. I upgraded my subwoofers and added a 300 watt amplifier for them. Eventually I'd like to add another amplifier for the rear doors and for adding an extra 2 full range speakers.
 

·
Registered
Joined
·
4,107 Posts
I have the two non-Bose rear deck speakers and the two rear speakers. My car's rear shelf doesn't allow for speakers, but I have purchased a 2nd hand shelf with speaker covers.

I have already installed the rear door speakers, but I couldn't connect anything as it seems my car doesn't have the wiring harness (I assumed that it was part of the antenna wiring harness; guess I was wrong...) I'll be taking a look into it as soon as I am done with the W123.

What I am unsure of is whether I need a amplifier to drive the 4 rear speakers. My car currently has 4 speakers up front (2 in the dash, 2 in the doors, original MB) that seems to work without an amplifier. But it seems like I can only drive two more speakers from my radio.




I'll be watching how this goes, but I'm not a fan of 6x9s either.
 

·
Registered
Joined
·
1,438 Posts
Discussion Starter #8 (Edited)
The front door and dash speakers are connected with each other. From the radio, the + and - output wires connect onto a four-wire connector, one set of + and - wires going to the door speakers, the other + and - wires going to the tweeters in the dash.

It's the same with the rear door and deck speakers - they're also connected with each other.

I don't quite know what effect this interconnectedness has on the speaker impedance, though.
 

·
Registered
Joined
·
2,742 Posts
Curious as to why you guys dont like the 6 X 9s. I was going to install some myself, but would like to hear your opinions as to what makes them bad.
 

·
Registered
Joined
·
4,107 Posts
The front door and dash speakers are connected with each other. From the radio, the + and - output wires connect onto a four-wire connector, one set of + and - wires going to the door speakers, the other + and - wires going to the tweeters in the dash.

It's the same with the rear door and deck speakers - they're also connected with each other.

I don't quite know what effect this interconnectedness has on the speaker impedance, though.
A multimeter will reveal all, but I'm going to guess that the speakers are connected in series a.) to increase the impedence and reduce the current, and b.) to promote lower frequencies.

Curious as to why you guys dont like the 6 X 9s. I was going to install some myself, but would like to hear your opinions as to what makes them bad.
I had 4x6s in Donkey, before I upgraded to 10" coaxials.

The non-uniform radius of 4x6, and of 6x9 (which my father threw out of his Land Cruiser) causes unwanted distortion of the cone at low frequencies. What you want instead is a uniform, if large, displacement of the cone. High frequencies are not as severely affected since the amplitudes are much smaller anyways. But, seeing as the reason most people want to "upgrade" to 6x9s is to get more bass, the terrible bass distortion of 6x9s is defeating the purpose. I would much rather install 6" rounds and be done with it.

Do I turn my volume up when I drive? Well, my Bach is competing with a diesel engine...

I'm not saying you shouldn't do it. I'm only saying I wouldn't do it.
 

·
Registered
Joined
·
1,824 Posts
Curious as to why you guys dont like the 6 X 9s. I was going to install some myself, but would like to hear your opinions as to what makes them bad.
They do cause distortion because of their oval shape. On top of that, because of the larger cone size, they do not reproduce mids as well as smaller speakers. Your best bet is to go for 6.5" coaxials. Coaxial just means it has a tweeter built in. I encourage everyone to read my thread about my sound system upgrade. I'll post a link.

http://www.benzworld.org/forums/w202-c-class/2475425-upgraded-my-sound-system.html

I used Polk Audio DB651s (slim mount) speakers in the front doors, but you're better using the regular DB651, they will fit perfectly, while the slim mounts had to be modified in order to fit (the holes in the rim weren't far enough away from the center of the speaker, I had to hacksaw little tabs out of the rim, bend them outwards and drill a hole into them, it was quite a pain).

In order to pop the covers back on the subs, I had to cut out the inner plastic webbing on the subwoofer side of the cover, otherwise they wouldn't fit :D
 

·
Registered
Joined
·
1,438 Posts
Discussion Starter #12
My primary goal with the 6x9 installation was to improve the bass of my sound system, without going to the extreme of a dedicated subwoofer and amplifier.

I'm coming from a dual 12-inch subwoofered W123, so I know what bass should sound like :D . The 6.5" coaxials in the rear simply didn't cut the mustard in terms of adequate bass reproduction. I'm fairly convinced that the 6x9 speakers, hooked up to the Alpine subwoofer power pack, will provide adequate results, as it will also have a dedicated gain control knob with which to fine tune the system.

Incidentally, I cut off the wires going to the mids and tweeters of the 6x9s and hooked them up to the Alpine four-channel power pack. Until time being, I connected the woofer of the 6x9s with a separate wire, which, until I have the mono-amp, I have also connected to the stereo amp. I will use these wires as the input to the mono-amp, with a new set of output wires from the amp to the woofers.
 

·
Registered
Joined
·
1,438 Posts
Discussion Starter #13
Geez, I don't know if adding the mono-amp is even necessary - it's bumping rather nicely now :cool: . I tested everything last night with the back seats, parcel shelf and trunk completely stripped out; everything's reinstalled again. Can't believe what a difference the 6x9s made. Granted, all speakers are amp driven, albeit a very small amplifier. Nevertheless, I doubt the head-unit alone would've been able to reproduce such clear, distortion-free sound.
 

·
Registered
Joined
·
1,824 Posts
Well amps always help, enormous amps are overrated IMO. Better to use a higher quality lower power amplifier with less THD. I kept the factory HU, but replaced the tweeters, door speakers and the hatshelf subs. System sounds very nice. I do want to add amplifiers for the rest of the speakers though. I'll probably do it at the same time as I retrofit power seats (I've got 2 black leather seats from a c36 sitting at home), since I will need to route additional wires anyway.
 

·
Registered
Joined
·
1,438 Posts
Discussion Starter #15
I'm going to install my new Alpine CDE-178BT head unit today. Read about fine tuning a system with pink noise, so will try and set mine accordingly.

Went for a 600 mile road trip this past week: man, what a difference my sound system has over the stock one. Also, despite the hate towards 6x9 speakers, they do make a marked difference in bass response.

Oh, my fuel consumption was 37.3 mpg for the trip. Granted, I did only drive at about 64 miles per hour.
 

·
Registered
Joined
·
4,107 Posts
Read about fine tuning a system with pink noise, so will try and set mine accordingly
I wouldn't bother. Unlike a living room or auditorium, the car's interior noise levels vary with speed, weather, traffic levels etc. Also, the speakers are not all approximately an equal distance away from any listener (as they would be if suspended from an auditorium roof).
 

·
Registered
Joined
·
1,438 Posts
Discussion Starter #17
I wouldn't bother. Unlike a living room or auditorium, the car's interior noise levels vary with speed, weather, traffic levels etc. Also, the speakers are not all approximately an equal distance away from any listener (as they would be if suspended from an auditorium roof).
The Alpine CDE-178BT that I installed has digital time-alignment, which sort of counters your argument :nerd .

I researched the topic of tuning speakers in a car environment last night. The topic seems quite complicated, but I came upon a website that provided a very simplistic method of fine-tuning a car audio system using pink noise. I'm not saying it's the be all and end all of fine-tuning a sound system, but I have to say that after setting my head-unit's parametric equaliser to provide the following frequency curves, it does sound rather amazing.

I purchased and downloaded a smartphone app with the necessary real time analyzer tools. Granted, my phone's built-in microphone was the reference for the frequency curves, but I think it's pretty spot-on.

From the linked website, this is the ideal frequency curve that one should aim for, with less than 3 dB change between each frequency range. I got this spectrum exactly right, except for the 20 Hz range, which the 6x9s can't produce. I'll see what effect the new amplifier and gain control will have - however, based on the end-results today, I've come to realise that it wasn't really necessary to buy the mono-amp.



Here are some photos of the 6x9s in place, as well as the new head-unit:





 

·
Registered
Joined
·
1,824 Posts
I see you put some sound deadening material around the speakers. Why didn't you do the entire hat shelf right away? You would get much less road noise from the trunk that way. When I did my subs, I stuffed part of the space between the hatshelf and the metal deck with large, dense sponges. That did cut out the road noise coming from the trunk.
 

·
Registered
Joined
·
1,438 Posts
Discussion Starter #19 (Edited)
I see you put some sound deadening material around the speakers. Why didn't you do the entire hat shelf right away? You would get much less road noise from the trunk that way. When I did my subs, I stuffed part of the space between the hatshelf and the metal deck with large, dense sponges. That did cut out the road noise coming from the trunk.
Because I lined the underside of the parcel shelf with a layer of sound-deadening that's used between the rear bulk head and back seat from another W202 :wink . You can see all the black panel fasteners sticking out the top of the parcel shelf that I used to fasten the sound deadener with in the photo you're referring to.

 
1 - 20 of 20 Posts
Top