Bgw70

The GPS screen unit has been replaced and it works and looks fantastic!!! I found the unit on eBay and it was sold by a salvage yard from the west coast. The unit price was $200 shipped.
NOTE: the door did not match my interior color but I used the door from the bad screen and it is only held on with three screws.

Bgw70

The speakers should have been finished when I pulled the three way Sony 4ohm speakers out and replaced them with the stock ML speakers.

When I was in there, I noticed the mid-range speakers had been replaced with 4ohm speakers too. I decided to finish replacing 6x9 ML speakers and then to listen to the system. I must say it sounds fantastic. No more distortion, just a clean sounding system. I will say that the mid-range 4ohm speakers sound a little louder than I think they should be. Since they have less resistance they will draw more power and will be louder than they should be.

I decided to purchase 4ohm resistors rated for up to 50 watts. The additional 4 ohm resistance will make them act like 8ohm speakers and the resistors should not overheat since they are rated for more power than what will used by the speakers.






Passenger side. The two connectors in front of the speaker are for door lock and window switches.<br/>The connector just below the yellow X is for the three button seat memory control.<br/><br/>These speakers where in GREAT shape and were removed from a 2006 SC430 and purchased from a salvage yard I found on eBay. They were $80 each, shipped. I negotiated the price. Most, if not all people WILL negotists on eBay.





Drivers side. The large connector to the right of the yellow X is for the window/lock controls and the connector just below the yellow X is for the three button seat memory control.





This is the door light wires. Disconnect first and reconnect last.





NOTE: the GREEN cable releases the door latch.<br/>The WHITE cable is for the door lock.

iolmaster

iTrader: (1)

Just so you know, it is 4 ohms impedance, not resistance. You do not gain 4 ohms impedance by adding a 4 ohm resistor. And, it doesn't matter which side you place the resistor. Impedance is the sum of resistive, inductance and capacitive values. With speakers the inductance is the greatest value. Impedance varies with the frequency of the signal the speaker is seeing at any one time.

texsexlex

iTrader: (3)

...those rears are 4inch & you should be ok with your JL's. I know everyone says we have to use the 8ohm speakers, but I put 4ohm Boston Acoustic 6x9's (in the doors) & 4in (rears) about 6 years ago & haven't had an issue. Since i bought the exact sizes, there was no modification s needed & they still sound great

Bgw70

Thank you for the information.
What will be the result if I add a resistor in-line?
2ohm
4ohm

Does it matter if I use a 1/4watt or a 50watt?

I am trying to use these 4ohm speakers but reduce there volume level.

Since they are so small, is there really any concern about them harming the amp at higher volume levels?

The ML system really sounds very nice now! If only they would have put a little more quality in the speaker durability.

iolmaster

iTrader: (1)

First, do not add the resistor. You are doing more harm than good. It is not unusual to run 4 ohm speakers in place of 8 ohm. We did it all the time years ago in the audio industry. I ran 2 8 ohm speakers in parallel per channel (4 ohm nominal) with no problems at all. As texsexlex said he has been using 4 ohm in the system for years. For what ever reason, people have this incorrect understanding of speaker ohm ratings. It is not, I repeat not, resistance. It is nominal impedance. I will not go into it here. Now, impedance is a type of resistance, but not what you think. Although I do not know all the details of the ML amp I can only tell you that if I ever have the need I will have no issue putting 4 ohm speakers in my SC and I have a lot of experience with audio equipment. Do not take that as a guarantee. Some amps are more problematic than others. I think with texsexlex's experience, you are probably good to go.

I will try to answer the other question about speaker volume. When the amp sees lower impedance it produces more power. Thus making that speaker sound a bit louder. I know it is not what you want to hear, but mixing ohm rating will produce this imbalance in volume. If all the speakers were 4 ohm you would just turn down the volume a bit and no one would be the wiser. Good luck

ShawnOk

iTrader: (1)

I agree and disagree with iolmaster. Firstly, I agree do not use in line resistors. As iolmaster stated, they cause more problems than do good. Secondly I disagree that running 4ohm rather than 8ohm is less likely to cause problems. I went to a shop and paid $250 for two pair of Alpine (front and rear) and labor that they said were "compatible". By "compatible" they were only worried about the size, not the impedance. I was so angry. I've read so many posts with owners' amps burning out and whether it be from age or increased draw on the amp, I want to keep my ML amp running smoothly since it's such an expensive part. Older systems might have been ok to swap 4ohm for 8ohm, but why risk it? But I feel these amps are so sensitive and already have a bad track record with owners. So why would I do anything to increase the draw on the amp to increase the risk of failure? This would include using speakers with impedance that is not compatible. I was so angry that they tried to sham me. If they had told me in the start that I they were going to put a 4ohm speakers in, I would have said no thanks.
I've decided to try to keep the stock impedance as much as possible to try to keep the life of my amp. I am taking a risk by using 4 ohm speakers in the rear, I know. BUT i consider it a calculated risk rather than using all speakers at 4ohm, only one set does less harm, especially since they are in the rear and I usually turn the fader to the front to reduce supplied power to them. As the previous posted stated the volume is much higher than the rest of the system so the fading adjusts the sound to be more balanced. This is my personal belief but in nearly 13 years, and I push my audio limits pretty high (since I've piggybacked a JL A1200 amp and JL8w3v3), I've never had an amp problem thus far. Knock wood.

iolmaster

iTrader: (1)

"Secondly I disagree that running 4ohm rather than 8ohm is less likely to cause problems."

Huh?? I never said that. I do not know the ML amp at all. It may in fact be one of the ones that is problematic. Many amps have specs at power ratings for 8 ohm and 4 ohm. so using a 4 ohm speaker in a position that had an 8 ohm does not mean you will have a problem. You may, it all depends on the amp.

ShawnOk

iTrader: (1)

"It is not unusual to run 4 ohm speakers in place of 8 ohm. We did it all the time years ago in the audio industry"

I took this to mean that you are saying that putting 4ohm speakers in an 8ohm setup is an acceptable compromise. I do not feel that it is an acceptable compromise if the owner does not know that it COULD cause damage to the amp. Additionally, I seriously doubt that any installer or audio company would warranty a burned out ML amp after they install 4ohm speakers to an 8ohm nominal system.

Additionally, newer amps allow you to change the output power/wattage depending on the impedance of the speakers being powered per channel (thus wiring in series and parallel becomes important). The ML amp does not work like this, from my understanding. It is set to run at safe operation and temperature with 8ohm speakers in the cabin, and 16ohm subwoofer. Deviating from this "flight plan" will eventually cause damage. This is my understanding. Any additional draw in impedance will cause the amp to run hot and therefore more likely to fail... leading to a very costly repair or upgrade.

Bgw70

I want to sincerely thank you both for the information and education.
Here is my last question on the subject and then I will leave it alone.
What if I used a one or two ohm resistor instead? I ask because I really would rather balance the front speakers.
If you tell me no then I will most likely purchase two ML mid ranges because they are less expensive than the other speakers I replaced.
6x9 $80ea
Rear 5in $35 ea.

ShawnOk

iTrader: (1)

I was told that using resistors causes decreased power to reach the speakers. Therefore with time, the speaker remains underpowered which also causes damage to the speaker. Each speaker has a nominal operating wattage range also. It will also change the sound dynamics, as you experienced. Going to 4 ohm increased the sound on that specific speaker compared to all the other 8 ohm as it was pulling more power. Putting a resistor to make the system think it's an 8ohm speaker will fool the amp but the speaker would now be underpowered since they are made to work at 4ohm, therefore a resultant decrease in volume but also now deceases the speakers optimal power range and decreases the life of the speaker. Hope this makes sense.

Harold57

Just a little clarity here...

Speakers are rated in Ohms (resistance) but are not a resistive element, they are inductive. What that means is that the "resistance" is dependent on the frequency driving the speaker. If the speaker was purely resistive, adding a resistor in series would be proper. The loss in drive would be equivalent to utilizing a speaker with the higher resistance. I'd say to just experiment with it if you have the time and opportunity. The best solution is to use the proper rated speaker. (There were some mentioned in a thread some years back that someone found speakers with the proper rating. I don't recall who or what thread that was though.)

Will a resistor hurt the system? No. Will a resistor affect the performance? Maybe. Will a resistor affect the performance to the point that you can actually tell the difference? My guess is no but I've never tried it or researched it either.

Bgw70

After the brake master cylinder crisis, I finally had some time to finish up the speakers. As most of you know, I replaced most of the speakers with used but functional ML speakers except for the sub, look back in the thread if interested.
when I was replacing the door speakers (sony) with The correct ML woofers, I noticed the mid range speakers were not ML. Sure enough they were aftermarket 4ohm speakers.
After installing everything I was listening to the system and it sounds great but the mids were too loud so I decided to purchase 4ohm, 50watt resistors. I figured it would reduce the volume ever so slightly and the resistors would not over heat due to the power rating.
I installed them tonight and did a sound comparison with the resistors in and out. The system sounds much better with the resistors in place. It reduced the volume just enough, the mids can still be heard and everything sounds more balanced.
The cost was worth it also, $8 for two resistors vs. over $100 for two ML mids.
Here are some pics

Harold57

Nice job Bgw. One suggestion though, keep the load resistor away from the plastic parts. If it gets hot, it could damage the plastic over time.

Bgw70

That is a very valid point and I was concerned about the resistor heat also.

The stereo was turned up about 3/4 of the way to max volume for about 30min, every 10 min I felt the resistor. The resistor stayed cool to slightly warm the whole time.

This resistor is rated at 50watts but I believe the ML amp will push 25watts Max to the mids and 12.5watts is nominal.