I've bought Kenwood KDC-W7531 MP3/WMA/AAC headunit last week. "YES! It works with iTunes" (remember good old NetWare motto? ). Kenwood AAC decoder implementation supports .m4a-wrapped files (NOT .mp4 or .aac) with "AAC LC" profile (NOT 'AAC Main', HE or LTP). Technically, this means perfect playback of iTunes-encoded or FAAC-with-"-w"-option-encoded music, but not NERO Digital.

It also deals with VBR AAC without any trouble, even on extra-high bitrates. TAGs length is limited to 30 chars max (.m4a file can have longer tags, but only 30 chars will be displayed).

Sound quality of AAC playback outperforms mp3 or wma, as far as I can say. At least for few first hearing session...

Sounds like placebo.... or not, depending on the settings (definitely not with WMA ).

Are you sure? Is it right? I thought Nero would produce the same MPEG-4 AAC as iTunes, only with different ending, that can be easily changed.

Please, somebody help me!

I mean, I don't have an iPod, yet, for example, and I thought that I could play Nero-encoded AAC on them, couldn't I?

how crappy...

cant they get a copy of the mpeg-4 standard to check that the one and only official extension is .mp4

What do you mean? You can make m4a files with our encoder too, it's just another extension. Or is there some other issue?

The Kenwood KDC-MP428, the lowest end model that should support AAC playback, doesn't work, at least on any test that I've tried. I've tried FAAC-, Nero- and iTunes-produced files, wrapped in .mp4, .m4a, and raw .aac, in both CBR and VBR where available... No luck on any of them. About two weeks after I e-mailed them (it's been about 2 months since then) they e-mailed me back:



No response since.

Time to bother them again. You did pay for the unit, after all.

Some other issue, perhaps. I can't figure exact problem right now. May be Kenwood can't parse .m4a-container having more than 1 stream (NERO-produced files have 3 streams - audio, 'BIFS' and 'Object Descriptors')?

FAAC '-q 300' or iTunes 'VBR256kbps Hi Quality'. Even 'lame --alt-preset insane' can't stand near AAC.

Please provide some ABX or preferably ABC/HR results for that along with the samples you tested or you're talking crap. . Since you are new here, you will have to read the HA terms of service, especially TOS 8.

Seems to me that Kenwood guys are linked tight with Apple iPod. Isn't .m4a an iPod native extention?

PS: but you're right - all these artificial limitations from hardware-makers suck.

.mp4 is admittedly very confusing, as it cold be pretty much everything. If you get a file with an .m4a extension, you know it is an audio file.

No, not at all. The standard is .mp4, but .m4a is sometimes used to make clear it's an audio file. The files are otherwhise identical[1].

Hardware that accepts .m4a but rejects .mp4 is just braindead.

[1] That's not entirely correct, but it's close enough in practise.

I know that. Sad, but true: nor Kenwood, nor Pioneer can't see files with any extention other than .m4a.


Seems to be that end-user's carma is so. Manufacturers think a lot about profits, but don't think a bit about us...

Yes, I've finally figured out exact source of this issue. Kenwood can't parse .m4a-container having more than 1 stream (NERO-produced files have 3 streams - audio, 'BIFS' and 'Object Descriptors'). Removing all streams/tracks except audio, like this:
mp4creator.exe -delete=2 filename.m4a
mp4creator.exe -delete=3 filename.m4a
...helps just great.

The Chief is absolutely correct. I tried using Nero,Foobar2000, and EAC to encode and burn an AAC disc, and none of them worked. After reading this post I gave iTunes a try AND IT WORKED!!! You definitely have got to have the files encoded by iTunes and not by anything else for them to play in your Kenwood or Pioneer Car Stereo. I have a Pioneer DEH-4900IB Car Stereo and after wasting about 6 or 7 CDR's trying to make an AAC disc I finally got it to work after burning a Data disc on iTunes. So thanks to The Chief for posting this info on this forum.

I just wanted to add that I tried the FAAC-with-"-w"-option-encoding using EAC and when I tried to play them in my Pioneer
DEH-4900IB car stereo it didn't work saying there was no audio on the disc, but I did find out that you can use Easy CD-DA Extractor to encode to AAC/.m4a and it WILL play in a Pioneer or Kenwood car stereo just in case anyone wanted to know.

I bought this kenwood this weekend, it has mp3/wma/aac on the box etc. I don't have any wma/aac files to test with, but it works flawlessly with every mp3 I throw at it.

Ah, and very nice a front usb port or usb in general is becoming popular. I remember when I bought my kennwod device about two or three years ago, there were only very few car radios with usb support out there.

I burned many coasters trying to figure out how to get my [not iTunes generated] AAC files to play on my Pioneer head unit with "iTunes AAC support". I figured changing them to m4a's with mp4creator should work, but thanks to this thread I found out that mp4creator creates [seemingly useless] second and third tracks in the mp4 with metadata. I found that deleting the second and third tracks (using mp4creator's -delete option, as mentioned above) works beautifully, and I can finally play AAC files on my Pioneer without recoding! yay!
Thanks much Chief!

--Fritz

I just purchased this deck about a week ago. I came from a Sony CD deck purchased in 2005. The older Sony was nice as it supported VBR mp3's burned on data CD's and it had a rear aux input for my iPod. However, the aux input was very muddled and I was tired of burning 700MB playlists as they only held about 100 songs (I can't pick 100 songs out of more than 6000). The new Kenwood in the link above is very nice. The sound quality seems a bit clearer than the Sony as it lacks some of those Xplod features which just seemed to blast the low and high frequencies beyond comfort. The Kenwood has a UI that is more difficult to navigate though but I purchased a 8GB portable hard drive for $40 which is more than enough to hold a playlist big enough. I simply plug in the hard drive (it is about the size of a one dollar bill folded in half), set my deck to random, and I listen to my music. It will take about one week of 24 hour a day listening to get through my playlist. I have to say that I am very pleased with the AAC playback (only plays *.m4a mpeg-4 AAC files). I tested an AAC data CD and it seemed to stutter every now and then. I also tested a WMA data CD and it did the same thing. The mp3 data CD I tested played flawlessly though. I guess WMA and AAC require a higher bandwidth to play and the CD deck has trouble with it.

I am still very pleased though and recommend it to everyone. The front mounted USB port is welcome, it was the only one I spotted at Best Buy that had it. There was another Kenwood and one other Pioneer that had USB ports but they were rear mounted. They come with a extension cable to bring it to the front so it isn't that big of a deal. I would just rather have the USB port right there in the front in case someone wanted to plug in their portable player (such as an iPod or USB thumb drive). This CD deck has finally allowed me to switch to the AAC format for personal use as well.