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stereoaz, Car Electronics Technician
Category: Car Electronics
Satisfied Customers: 113
Experience:  35 years in car audio,my shop won iasca world title ,custom fabrication,expert installer.
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I play music through my high resolution "mp3" player in my

Customer Question

I play music through my high resolution "mp3" player in my car via the Aux-in connection lead. My music player plays my 24 bit FLAC and WAV files. However, the sound volume is too low and needs greater amplification.
Question: Is the most effective means of amplifying the sound best achieved by purchasing a headphone amp (e.g. the new Fiio A5) to connect my mp3 player to voia the Aux-in connection, or would the sound be best amplified by having a car amplifier fitted in my car (eg Vibe SLICKS4-V2 4 channel amplifier.)
I have a 2007 Mercedes C-Class which has a multi speaker surround style set up.
Thanks you for your advice.
Submitted: 12 months ago.
Category: Car Electronics
Expert:  umdterp13 replied 12 months ago.

The only limitation is your budget, point blank. It would, way beyond anything resembling a shadow of doubt, be better to amplify the entire sound system; that would be the best route imaginable. I see what you mean, and I would not give any consideration to the input level adaptation for pure signal purposes.

Customer: replied 12 months ago.
Ok - but the amplification of CD's is absolutely fine in. It is only the mp3 player via Aux-I which needs amplification. I wondered if a headphone amplifier would serve the purpose of amplifying the mp3 player sound via the car speakers?
Expert:  umdterp13 replied 12 months ago.

Technically yes, regardless of "power" and as such distortion would naturally be the part where volume would reach its limits. I can say you would definitely notice a difference with the headphone amplifier and as such, or should I say to what extent would an improvement make itself known, is literally going to be the upper limits of not only excursion per speaker but also clarity of the treble range. Ideally you want each channel to push as much power as possible consistently; which is where you derive the RMS rating of head units and speakers. That is where the differences are noted. The overall effect will be enhanced, although I can guarantee an amplified extension of the DSP that is factory equipped will leave you without question.

Customer: replied 12 months ago.
Thank you for your response. I will in that case investigate the costs of installing an upgraded amplifier and subwoofer to enhance the sound of my car stereo system. I believe I would need a sound processor as well? I don't play CD's anymore, only using Aux-in to play my mp3 player so I just wanted to make sure I am realising the benefit of hearing high resolution 24 bit sound - without spending a fortune to do so. I guess headphone amplifiers are designed for headphones only but could be used - but to far less effective results.
Expert:  umdterp13 replied 12 months ago.

Correct, and JL is a good place to start on integration; there are others.

For the price you can certainly try the headphone amplifier, it won't break anything within reason, and go from there.

I would recommend setting the volume around 90% on the part of the amplifier and tune the radio to your preference.

Customer: replied 12 months ago.
Thank you so much. My car speakers are 450 watts and there are 12 of them in my 2007 Mercedes C Class so I don't need huge amplification. I have read good things about the new Fiio A5 headphone amplifier which has just been released this week for £100 so I may try that first. I can always use it when I play music through headphones if it doesn't do the job in the car, so it won't be wasted money. One last question, how will the headphone amplifier work with the existing car amplifier? Will it just enhance the overall sound amplification or will it compromise the existing car amplifier, or nullify it? I guess both amplifiers will be in operation when playing an mp3 player via Aux-in connection lead?
Expert:  umdterp13 replied 11 months ago.

Broken down for you, the source in this case being the AUX MP3 player will function independently of all other systems. The Headphone amplifier will essentially add volume, the signal from the MP3 player will have extra voltage for lack of a better word added to it, which arguably gives a cleaner sound to the car itself. Its like having 2.5v pre amp outputs from a head unit and switching to 5 v in that sense, overall better quality as the signal itself has much more potential for exploitation by the system where there wouldn't be many gaps between frequencies. What I'm trying to say is its the same audio regardless of what is done with it, that much has been established. What the benefit of amplifiers are in the sense of traditional car audio to the speakers is clarity like you wouldn't believe. Every note is heard cleanly given the proper adjustment. What you are getting out of a headphone amplifier is, for all intents and purposes, next to nothing beyond the stock audio system your car provides. They are different playing fields all together to compare the two types of experiences. The headphone amplifier will not compromise the existing stock setup, although I would caution against excessive volume in terms of the MP3 and the headphone amplifier. I would set both near 90% at most and adjust via the head unit of your vehicle for volume purposes. It won't necessarily nullify anything beyond the mention of all things being equal considering the file being played / processed at any point, and as such yes both amplifiers will be in operation simultaneously. What can be expected is a lower volume setting without a compromise in quality of sound until further upgrades are done. I could go on, since it is a rather complicated system at work.... as the head unit will process the sound and the amplifiers will distribute power accordingly to speakers only reacting to the frequency range. Once again, more power will increase quality and cleanliness significantly; whereas overcompensation of the headphone amplifier will cause distortion and give the music hollow, shallow sounding effect where the signal is literally stretched a little too thin.

Customer: replied 11 months ago.
Thank you so much for such a comprehensive explanation which has been extremely helpful. My car operating manual for the audio states that the volume of Aux-in will depend on the MP3 player connected and warns that it may be a lower sound volume than the CD player. My preference would be to install a high resolution amplifier like the Sony XM-GS4 Channel Stereo Amplifier but will that make Aux-in equal sound volume to the CD player, or will Aux-in still be the same proportional volume (ie louder than it is now, but still lower volume when compared to the CD player). I suspect that the volume levels will remain proportionate.
Expert:  umdterp13 replied 11 months ago.

Well at that point, you would need component speakers to compensate for the high and low range frequencies, rewiring the whole audio system, and a sub more than likely for a legitimate system to take place. Or, at least a mono amp for the one already there provided there is one. Like we began, money is the sole discretion for audio in this case.... there will be no comparison at that point, period.

Customer: replied 11 months ago.
Thank you for all your help and advice, much appreciated.
Expert:  umdterp13 replied 11 months ago.

No problem whatsoever, thank you =)