BlueBoxer

iTrader: (13)

I have the Alpine full speed ipod control with my IVAW200 and noticed that when I switch from the ipod to the dvd/cd player as my source, the ipod is noticeably louder than when I play off the cd/dvd player. I assumed that the mp3 format and the compression it uses would diminish the quality and I would have to play those files at a louder volume, but I guess I was wrong. Can anyone explain this occurence? I am interested in whether its just the digital formal beign superior to the cd or if it is another factor.

Best Regards,

Sonny

JimRHIT

iTrader: (6)

It just means that the signal you are getting from the iPod is louder ... not that there is less noise there. Essentially ... the signal to noise ratio may be worse ... but the input voltage is hot enough to "sound" better (ie-louder) than a cd

Paul350Z

iTrader: (1)

MP3 is a lossy form of compression - tons of bits worth of data are dumped to compress the file size - which ain't got jack to do with the overall signal to noise ratio for the most part. In extremely small MP3 file sizes you'll notice a loss of dynamic range. It might be hard to understand but louder isn't necessarly better. CD's use a fixed sampling rate designed to capture all (as much as possible) of the music. It can be argued that a higher sampling rate allows for a more accuate capture but back in the early 1980's 44.1 Kbs seemed hard to do.

MP3's are only barely music when compared to a CD or better yet a full analog source. The MPEG algorithm drops amazing amounts of music from each song in order to get the high level of file compression. The compression (reduction) of dynamic range (quite music to the loudest music) is a production "value" that the producer inflicts upon the music. Ray Orban did a study and has proven that decade by decade the music is getting louder and louder showing less dynamic range. Producers are attempting to limit the dynamic range as much as possible keeping the sound level as high as possible.

BlueBoxer

iTrader: (13)

Do you gentlemen have a resource site you can reference. I would love to read up on this subject. I picked the Alpine due to the cd signal to noise ratio. Although the ipod definately sounds louder, I have not noticed a huge difference in quality in comparison to the cd/dvds I play. When I toss in something with more of an acoustic range (Clapton, Santana, etc...) there is a difference, but on 80% of the tracks I play there is a neglible difference.

JimRHIT

iTrader: (6)

Paul - the MP3 signal comes in hotter, therefore its louder. I stated that it had a higher sig/noise to say that it wasn't better quality.

About the diff in MP3/CD ... we did a fun study at Klipsch trying to prove the "myth" that you could hear it. Guess what ... every set of "golden ears" ... and engineers included, failed the test past 192k encryption. I'd challenge you as well to try this, but you have stated your hearing loss over the years to be quite bad.

Anyhow ... one has to lastly look at the environment that this source will be listened to in ... a very high noise-floored vehicle in motion ... not the ideal listening room.

Ahsmo

iTrader: (13)

+1

I cant hear the difference between my focal sq CD and the ripped 224kps versions of the same tracks.

Paul350Z

iTrader: (1)

Past 192 - which way? Above 192 Kb/sec agreed. Below 192 it depends. The PBS radio stations hired a consultant to conduct tests on "average" listeners to compare MP3's at various rates - the paper was presented at last years Radio National Association of Broadcasters meeting.

True, true. Agreed that in the car - no way! As soon as I awaken my 300 ponies it gets pretty noisy. Your +90 dB signal to noise ratio starts off with 40 or more dB as a noise floor ... and 130 dB isn't my idea of music.

Dang, can't find the NPR study ... I've got a hard copy at work. We're not using MP3 at our radio stations despite it's compression advantage but it is a split vote. The DoD, Army, and Navy have voted against the MP3's - only the Air Force is doing MP3's at their radio stations.

VenomZ

iTrader: (1)

Off topic but...

That's not true in all cases, you can't just generalize mp3. There are different codecs and some are better than others.

Have you heard the difference in quality between say LAME and the fraunhoffer codec? It's night and day..and with all encoders, you still get to choose the bit rate at which to encode..