beantownrich

I gotta tell you, I'm not impressed with the standard BOSE system that comes in the SLK (R170). The sound quality is "tinny" to my ears. I don't usually tinker with car-audio but I feel that the lack of sound quality is forcing my hand.

So, am I right in assuming that I can pull out the stock head and 6-CD changer and just replace them with better components?

I think the speakers are fine. (I dont really have room to fit anything else).

I'd appreciate any advice you may have to offer.

Richard.

NightSea

1. Is that Bose sound option?
2. What is your favorite music?(Classic, Jazz,Rock..which one?)
3. What do you mean by "lack of sound quality"? SPL?


I have spent more than $40,000 for changing audios at MB cars.

Aletank

If you have a look at the BOSE UK Car Audio Site It explains that the BOSE systems are very complex and it's not possible to change Head Units
I wasn't impressed with the standard sound system in my car (Wasn't BOSE though)so this is what I done to mine My Audio Install Thread - Pics There Too

beantownrich

By lack of quality, I mean that I think the sound is very unbalanced. I know that I am driving a roadster, so I don't expect too much when the roof is down. When it's up though, I expect a sound quality that is inline with a prestige marque coupe.

I find that the bass, while there, only extends to the very lowest registers. The low-mid range is quite weak, the mid-high range is ok, and the top-end is very present.

I've toyed with the bass/treble controls but really am never satisfied. At least the addition of a decent EQ would help; I am sure that the audiophiles amongst you would perhaps criticise this approach in favor of a better head unit.

The trouble is, I'm not sure how to go about replacing the head unit.

byip25

bose is far from a good brand of automobile stereo. i couldnt take my bose system for more than 10 days after getting the car. i spent a month before getting the car convincing myself i was going to leave it stock too. it sounds like you need some upgrading by replacing the 6.5 inch speakers in the door. bostons or mb quarts would improve the mid-range bass sound. upgrading the head unit depends on what functions you are looking for and the amount of expansion you plan on doing.


b

beantownrich

Good idea, replacing the speakers would be a good start.

In the SLK we have a 6 speaker setup, one large woofer placed in the bulkhead behind each seat, a smaller one in each door, and a tiny tweeter set into the door handle panels.

Fortunately for me, the head unit in the SLK is standalone, I dont have any phone functionality, so if it is feasible, could easlily pull it out and replace it. Of course, I'd have to shed the MB changer, as I assume it and it's connections are incompatible with non-MB heads.

I guess it all comes down to whether the head mounting is the right configuration to take a non-MB system, whether the power and speaker connections are compatible (I assume they would be).


Added: I did notice that the system is integrated with the teleaid system, this worries me a little bit as I would like a new head unit to be integrated to this, and I can well imagine that this is not possible.

As you can see, I'm all assumptions at this point and could use a little help.

peet

I'd be really careful about swapping out speakers only - the best that will happen is that the volume will be WAY low the worst is you'll cause a fire.

You see the Bose (well at least the W203 chassis bose) runs at 2.6Ohm -- most aftermarket stuff is at least 4 - if not 8.

If you popped in an 8Ohm element youd be under-driving it, and showing a higher resistive load to the amp.

I am still trying to sort this out myself as I totally agree with what you said - but I am in a C230 coupe.

Good luck and post your findings.

P

amdeutsch

Well here's my $0.02. To the best of my knowledge the BOSE amp will pick off the signal from the std HU (Easy test to verify. Pull out HU and connect a speaker to the leads. If it plays - AHEM). Within the amp you'll find the EQ circuitry which gets amp'd and then fed to the BOSE spkrs.
A lot of people on the W203 thread have upgraded their HU to the Audio 10 CD. Functionality is preserved even to the CD changer. You might look there and contact them.
Good luck

NightSea

As I understand,


1. Sound signal process
Head unit (MB 10,30,or COMMAND)---> Bose amplifier ---->
Bose speakers.

If you replace the head unit only , you will lose any function
specific for your car and ,according to my experience,
don't expect big difference from the current one.

Additional EQ ( active equalizer) can be inserted as long as
you can meet a good professional who knows Bose car
amplifier's connctor structure and can convert it to take
a new EQ. This EQ will be installed at the trunk.


2. Bose amplifier has its own equalizer to segregate low,
mid, and high range frequencies for speakers.
As the equalizer is a part of amplifier ,
it can not be seperately controlled.

HOWEVER YOU CAN BUY TWO NEW PASSIVE EQUALIZERS
WHICH HAVE 3 RANGES EACH, AND LOCATE THEM
BETWEEN MID RANGE SPEAKERS AND BOSE AMPLIFIER.
(HERE YOU WILL USE ONLY MID RANGES OF 3 RANGES EACH).


3. Bose speakers are basically so-called reflective acoustic .
And their places, especially at doors , are designed for
Bose speakers. If you remove them from doors , you will
find there are specially designed air holes.
This means that door speaker replcement may need
speaker housing reform.

4. Bose amplifier has line input and speaker output, but
the connectors are not RCA jacks. However , a good
professional can tell those lines and convert them for upgrade.

5. If you feel weak of mid-range sound , first step to take ,
I think, is an experiment ; that is , move out current speakers
with extending lines and temporarily turn the faces of them
to center-high( level of your ears).

6. And play your best favorite music and compare .
You better play many kinds of music .
(Your favorite music and favorite volume quantity are
very important factors.)

7. Meanwhile , car audio shops usually have computer
equalizer( so called pink noize generator) . Ask them to check
the acoustic sound dispersion of your car with top down.

8. 4 to 8 ohm speakers with 2 ohm amplifier out put ;
theoretically not good , but practically no problem.

peet

More than likely practically - overheated cabling/amp = fire.

Find me this man and I'll show you a bilogical AD/DA converter. The Bose amp (at least on the newer models) is fed intravenously via fiber optic cable. No line in - no RCA - not even a simple hard-wired cable.

Back to the drawing board! I too wish it were simpler.

Peet

NightSea

As Peet points out,
I made a mistake.

I was occupied with old Bose system's connecters.
(Actually confused with old and new ones.
....getting older and older )
D2B system Bose is using now has fiver glass .
One time I tried to insert an MD player using fiber glass
output , but failed as I needed an fiber glass input also)


Sorry for posting wrong information.


But connecting 4 ohm speakers , as far as I experience,
no problem.
Instead , connecting speaker having lower ohm gives
a problem ( heat --> short cut ).

peet

If anyone has more info on impedance matching I sure would appreciate a link.

If a simple circuit can be hooked up (resistor - that would increase the impedence no?) ... then I'd be interested in playing some with the elements.

Thanks!
P

Kal Rubinson

There's no useful way to change the impedance of the speaker. Increasing (by adding a resistor in series) or decreasing (by shunting with a resistor) will result in significant power being dissipated by the resistor. Thus, any improvement due to impedance matching is paid for in loss of efficiency.

Of course, you can add another (identical) speaker in series or parallel, in place of a resistor, but then you need to find a place for it.

mctwin2kman

Using a higher imedance woofer will actually use less power from the amp causing it to run cooler not hotter Peet. I used to install systems in cars when I was in college, as well as being an Electrical Engineer. Now if you were to find two 4 Ohm drivers and run them parrallel you would effectively create a 2 Ohm load, which in turn would be bad since it is lower than the 2.6 that Bose uses. If you were to install 4 Ohm drivers and run them off the factory amp, you would notice a decrease in audio volume at the same physical volume level. So in effect there would be no point in that, because most would want louder. The only really easy way to do it would be to replace the Bose Amp with a higher power one, that could handle the 2.6 Ohm load of the speakers, but then most would replace the speakers as well. This was the person could keep all the functionality of the factory Head Unit. But that would be one heck of a task just to keep the tape deck. There are many options, and once I get my car I will most likely play a bit to see what I can do. Hopefully one could tweak the amp, while voiding the warranty at the same time.

peet

Thanks for that info. I actually have the Audio10 CD in my dash... but want to keep it for the integration. I would like to increase things in the quality dept on the cheap if I can - and gutting would not be cheap!

Keep in touch!
P

peet

One more thing... what if I add a 4Ohm driver to the 2.6Ohm that is there? Would I effectively create a 3.3 - that would make a smaller volume reduction than having a pair of 4's.. but how much less?

Kal Rubinson

If you put the 4ohm in series with the 2.6, you get 6.6ohms. If you put it in parallel, you get 1.6ohms. Neither works.

amdeutsch

Peet,

Actually here are the formulas for you to use:

Parallel: (R1R2)/(R1 + R2) = R total : i.e. Bose spkrs (R1) = 2.6 ohms, your speaker (R2) = 4 ohms => (2.6*4)/(2.6 + 4) = 1.5757

Series: R + R = Rtotal i.e. Bose spkrs = 2.6 ohms, your speaker = 4 ohms => 2.6 + 4.0 = 6.6

Hope these simplified formulas help out.


In reality spkrs are complex. Just because they are called Xohms doesn't mean they will behave that way; frequency, compliance etc., etc. get in the way here. If you want to know more PM me otherwise it would turn into a dissertation on here.

Oh yeah,
I'm a "SPARKY" too

mctwin2kman

Well, I did not listen to the radio when I test drove the car so I do not know how loud or not loud the system is. But 4 Ohm driver would require you to turn the volume up higher, but in turn should be cleaner sounding. So I would try changing the speakers in the doors, up front and then see what it sounds like to you. That is by far the least expensive thing to do. You probably could replace the Bose amp as well, but that may be a wiring mess. You would need to get line converters for front and rear and find an amp turn on lead then hook the outputs up. It is feasible, but would take a bit of time. May end up sounding great though.

Edit: Hopefully if I get the new job I am interviewing for tomorrow I can order my car before next year. My house payment went up $200 because someone at the bank does not know how to figure escrow right, so the car is put off for a few months. But hey if I get a new job I get a nice fat check for my ESOP to put down on it.....

amdeutsch

Cut out the bank, put something into a separate savings account every paycheck and you'll will have enoug to pay it on your owm. In addition you'll draw interest instead of getting nothing at all.

mctwin2kman

Unfortunately I could not since, I just bought the house a year ago, and it is required to have the escrowed taxes and insurance. It is fine though it will go down $100 a year from now. I just owe them the taxes from last year now, well part of them. Plus I am finishing a loan in December plus the money I will get from the company, $6000 after taxes, plus the extra from the new job, whenever I get that. I will be all set, I just have to pay down some of the wife's credit cards because my credit is still a little shot. Should be right back on track in less than 6 months as that will be 4 years since my stupidity. So it just puts off the new car a few months, oh well, maybe they will have more mods by then.

NightSea

1. Speaker ohm is not the only one factor to decide the quantity
of sound. There is another factor, db at 1m distance.
Each speaker has its own db( efficeiency).

2. Human ears don't respond mathmatically to electricity.
100 watts does not mean that you get the volume 10 times
more than 10 watts. Our ears will listen only 2 times more.

3. Try any speaker ohm change ( ex; 2.6 --> 4) and you will
find it is not so easy to tell the differnce of volume . Believe
me. I did it so many times.

4. Acoustic factor we should think also. If you have a mini stereo
system , try to reposition its speakers in many ways.
Evertime you feel the difference. At any car, this acoustic
factor ( basically the direction of speakers) is very important.

5. Everybody has his/her own favorite sound quality.
Sharp, smooth, strong, delicate, or ..... Yesterday I listened
my friend's new car audio. He bought a high-end head unit (
$ 9,000 only for the unit ), and installed a tube amplifier , etc.
My impression it was good for the Baroque , not for Queen.
I believe that the favourite style should be considered
for any car audio upgrader.

6. Our ears are good to pick up the mid range among 20-20,000
hz. To make this stronger, making other ranges weaker is
another possible way.

Dema

A tube amplifier in a car? Very nice.

mctwin2kman

NightSea,

You are correct in all your assumptions. The speakers would be the best way to go first. A really nice driver and some high end tweaters will add so much. Mid-Bass fill is what is most likely needed with the addition of some cleaner highs as well. The one would work on the subwoofer issue later depending on how new mid-bass drivers would sound in the doors. And a tube amp is a sweet deal in a car, unfortunately probably expensive as all as well. MacIntosh makes a great amp, if I could find them around still that is what I would buy, they used to be tube, I am not sure if they still make them.

peet

Thanks all for the formulae. That helps a great bit.

I agree, watts, amps and ohms do not make a system. BUT - that is where we start. One does this to make sure that a) fire doesn't start, b) things will sound somewhat decent before cash is put across the table and c) see a.

I have a pair of a/d/s 345is mids sitting around. I will try and swap them in place of what is there now. We'll see!

Although, I may try something a little more twisted..

4" 4Ohm A/D/S mid in rear. The lowered volume can be offset by using the fader to rear which in turn will up the bias to the sub (it is wired off the rear channels).

Let's see what that does. Then it's on to the fronts (at least those nasty tweets).

Cheers all.

P

P.S. Tube amp in car? the shaking can't be good for all those elements in a tube. Nice solid state technology... Xtant or A/D/S... as far as my amp of choice for home? Krell power!