I have read that the Monster iPod charger you have also has bad alternator noise problems.

Can you confirm?



The best way to test is to plug in the iPod, and leave it turned on... but paused.
Then turn up the volume on the car radio, and step on the gas pedal a few times.
Listen for a whine that gets faster and higher pitched with more acceleration.

 

I've already shipped the charger dock back to the manufacturer for a refund.

:thumbsdown:

 

OK--I spent a few minutes testing this in my car. With the car running, while listening to the iPod, I turned the volume all the way down, and paused the iPod. Then, using the volume knob on the dash, I turned up the volume until I could hear something.

Test 1--iPod connected to Monster adapter with mini-stereo cable plugged into Monster adapter:
After increasing the volume nearly 2 full rotations of the knob, I heard what sounded like static, then I revved the engine and at 3,000+ RPM I could hear a faint whining sound, which got a bit louder and higher pitched as I revved further to about 5,000 RPM. Above 3,000 RPM, as I lowered the volume the whining sound disappeared almost immediately.

Test 2--iPod connected to Monster adapter with mini-stereo cable plugged into headphone adapter, and iPod volume turned to max:
After increasing the volume nearly 2 full rotations of the knob, I heard what sounded like static, then I revved the engine and didn't hear a whining sound.

Test 3--disconnected Monster adapter and plugged mini-stereo cable into headphone adapter:
Same as test 2.

Test 4--both Monster adapter and mini-stereo cable disconnected from iPod (and disconnected from each other):
Same as test 2.

Test 5 could have been disconnecting the Monster adapter from the car to see if that eliminated the static, but mine is hardwired and I didn't feel like taking apart the rear center console!

Based on the above, my conclusions are:
1. After raising the volume nearly 2 full turns, you start to hear static regardless of the 4 configurations tested.
2. With the Monster adapter plugged into the iPod and the mini-stereo cable plugged into the Monster adapter, with the volume raised nearly 2 full turns, a faint whining sound is heard starting around 3,000 RPM which gets a bit louder as you rev to 5,000 RPM.
3. The whining sound doesn't exist with the mini-stereo cable plugged into the headphone jack.

So yes, it turns out that the Monster adapter does cause a whining sound at extremely high volume levels, with the engine at 3,000+ RPM.

I'm sticking with my configuration because the only difference is the faint whining sound with the volume turned up nearly 2 full turns and the engine at 3,000+ RPM. I would suggest that under those conditions with music playing, even an audio aficionado would be hard pressed to hear any difference while driving (given road noise)--or even while parked. The whining is so faint that it would be overwhelmed by the music, and I don't think I'd ever listen to music that loud in my car--for kicks, I tried seeing how loud was comfortable, and once you approach 1.5 turns, it sounds like the speakers will break.

I also did the above tests with the car off and the ignition on. The only difference was the whining sound wasn't present.

 

Awesome.

Thanks for the reply.



I listen to my music with the car volume at max setting.... so I would always have the whine.

 

I also like to listen to my music cranked up (when I'm alone in the car) but I could not imagine listening to music in the car at anything approaching 1.5 rotations of the knob, let alone at max setting (which I honestly believe would blow out the speakers...or my ear drums... )

Since I spent the time testing for you , why don't you do a test for us? Using the volume control knob, turn the volume completely off, then rotate the knob until it's at the "max setting" level that you like to listen at. Let us know how many rotations of the knob it is...

 

Since I normalize my MP3s, I also never listen to music at the max setting on my Alpine (35 out of 35, with 1000 watts to the components this would make you go deaf in a VERY short period of time), but at car audio competitions they do perform tests for hiss and alternator noise at max volume, so I couldn't have this.

 

Following your advice (thanks! ), I ripped my CDs using Exact Audio Quality, with LAME encoder @ 256kbps VBR, and normalized using MP3Gain. While I understand that at car audio competitions they may go to extremes, do you feel that the average--or even very above average--listener would really hear these noises at reasonable listening levels? That's what we're trying to do here-is give the less-than-audio-competition-level person sound (pardon the pun! ) advice.

 

I will perform the test gladly, tomorrow.

I just went and bought the Monster cable charger, with line output. After plugging it in, I have noticed that the alternator noise is less than my other charger... but still present. It does, however, depend on how far you push the charger plug into the cigarette socket. (ie if I don't push the charger all the way in, the alternator noise is less)


As for the volume levels: One thing to remember. The volume on the car radio is not an absolute. It's relative to the recording you are listening to. The human ear determines perceived volume level by the RMS output of the music, not the peak output. So there are tricks which can be performed in audio mastering to make the perceived volume louder on a CD or other recording.

I listen to dance music which I record in my home studio, primarily. I have years of audio experience, and I master my own recordings. I don't use heavy compression like many store bought CDs have. I record at reasonable levels and maintain the dynamic range of my original sources. So when I turn my radio up to full volume, and play a recording I made.... it is not going to be the same earsplitting, clipped, square waves that your recordings obviously produce.

 

Given the difference in noise based on how far you push the charger into the cigarette lighter socket, do you think my hardwire install makes the noise less or more pronounced?

 

One last test... I actually use the OEM iPod dock in my setup. So, the 1/8" plug goes into the dock and the monster charger is plugged into the dock as well.

I will listen for whine in the morning.