Sound quality on Dice Unit

I used the Coastal E Tech Lockpick to do AUX in to my base 07, and while I'm perfectly happy with the quality of the sound, I have the exact same problem with the sound level through the Lockpick.

 

<div class='quotetop'>QUOTE(priusFTW @ Apr 3 2007, 03:17 PM) [snapback]417275[/snapback]</div>

Cliffs-notes/Official Answer: It's not the DICE kit. It's the Equalizer in the car stereo that's causing it.

Vagabond's Answer: If you wanna hear something interesting, take that same MP3 file and burn it to CD. You'll get the same effect. When I installed the DICE kit into the 07 Prius, I heard it. It's the Exact same thing that Sillyboy is trying to hash out with his threads I believe.

But I know what you're talking about. When I installed it in the 07, I heard a distrortion on some track's bass. Not all of them. I'm gonna look at how it's encoded and see how the Prius prefers how the encoding is done.

Next, I took the same DICE unit and put it in my 05 and it sounded perfect. I tested another DICE unit and reproduced the same thing. So I know it's not the DICE kit. After that I tried the burning the same MP3 onto CD and got the distrortion. The reason why you're not hearing it with the AUX jack is because the iPod (Or any other device that has a 3.5 jack) is handling the Equalizing work, with anything that uses the data jack or CD the car stereo does the EQ work.

The EQ in the 06-07 is not as good as the 04-05's. I don't know why, but I assume it's part of the fact they added the mp3 decoding. I'm gonna fiddle with the mp3 file.

Does Sillyboy have any input on this? He seems to know about how sound is filtered by device and I'm curious on his thoughts.

 

<div class='quotetop'>QUOTE(priusFTW @ Apr 3 2007, 03:17 PM) [snapback]417275[/snapback]</div>

That's interesting. I experienced the complete opposite my 2007 Touring Package 3 (yes bluetooth - no nav) Prius. Actually I was quite surprised at how much better it sounded and also how it plays out of all speakers a lot more clearly than before.

One note. Check to make sure that "sound check" is NOT enabled on your iPod.

 

<div class='quotetop'>QUOTE(priusFTW @ Apr 3 2007, 06:17 PM) [snapback]417275[/snapback]</div>

What caused you to expect "better than CD sound" from compressed files off an iPod? Your factory stereo isn't even capable of reproducing the full quality of a CD, let alone better.

 

<div class='quotetop'>QUOTE(mike.s @ Apr 3 2007, 04:06 PM) [snapback]417304[/snapback]</div>

When you rip a CD at the maximum rate of 192kps the iPod is going to output it at the same. If you are somehow able to obtain a copy of the same track at 320kps or in LAME it will sound better. Naturally, you are limited to the quality of the speakers, but I just thought I would add that.


I'd like to add something to my previous post. The gain from the DICE kit may be too loud for the stereo. The easy way to test is to check if the volume from when you use the DICE kit is noticeably louder than from using the FM player or CD. Have you noticed something like that?

<div class='quotetop'>QUOTE(OlsonBW @ Apr 3 2007, 03:54 PM) [snapback]417298[/snapback]</div>

Toyota may be using multiple headunit manufactures now, that could be the factor. One brand may be slightly superior than another. Since the Prius I have is brand new, I was going to take it to the dealership and act like the owner and try to get some info.

<div class='quotetop'>QUOTE(adam1991 @ Apr 3 2007, 03:29 PM) [snapback]417285[/snapback]</div>

Thanks, you proved my statement/theory.

 

<div class='quotetop'>QUOTE(Vagabond @ Apr 3 2007, 07:17 PM) [snapback]417305[/snapback]</div>

The rate for a standard CD is 1411 Kbps (not "kps") - that's 44100 16 bit samples per second in stereo (44100x16x2=1,411,200 bps). iTunes has a maximum encoded rate of 320 Kbps for MP3 and AAC. But, it also supports lossless encoding and PCM (AIFF, WAV), which reproduce full CD fidelity (subject to any hardware limitations).

 

<div class='quotetop'>QUOTE(mike.s @ Apr 3 2007, 04:56 PM) [snapback]417315[/snapback]</div>

my bad on the typo. There's plenty of superior programs compared to iTunes out there. Not to mention, just because the program supports it, doesn't mean you're using it.

Mp3's from most online stores are usually 128 to 192kbs As for CD quality, refer to this chart on this site about 1/3 of the way down on quality. I say 192 is CD quality, others say different.
http://teamcombooks.com/mp3handbook/16.htm


As for this "The rate for a standard CD is 1411 Kbps (not "kps") - that's 44100 16 bit samples per second in stereo (44100x16x2=1,411,200 bps)" um, this is uncompressed. This has nothing to do with any file format other than WAV. If you're going to use this as an example, you should know that each song would be around 11 megs Per Minute That's around 6 times larger than a equivalent quality MP3.

 

<div class='quotetop'>QUOTE(priusFTW @ Apr 3 2007, 08:29 PM) [snapback]417326[/snapback]</div>

Sound "quality" can be objective, or subjective. Subjectively, some people think louder (even with more distortion), with compressed dynamics and with a mid-bass hump (think Bose) is better than undistorted with a flat frequency response. I won't argue, people like what they like.

No, I don't believe that the sound quality from your iPod is better than from a CD. The iPod can, at best, equal the sound quality from a CD. There can be differences in sound quality between CD players, but as long as <$20 or obviously defective ones aren't considered, those differences can not be heard on a factory car stereo system.

 

<div class='quotetop'>QUOTE(Vagabond @ Apr 3 2007, 09:03 PM) [snapback]417343[/snapback]</div>

And what, exactly, is your point?

I asked the OP why they expected "better than CD sound" from compressed files off an iPod.

At that point, you piped in with something about ripping at a "maximum rate of 192kps" off a CD, and implied that "320kps" or use of the LAME encoder would therefore produce better than CD quality sound. That's simply not correct.

Apple Lossless format will produce full CD quality sound, but still provide around 50% compression. That's a format "other than WAV," as is AIFF. The iPod does not support ANY "better than CD" quality formats (such as SACD, or the higher definition DVD-Audio formats. Such support would be necessary for the iPod to provide "better than CD" quality.

 

<div class='quotetop'>QUOTE(mike.s @ Apr 3 2007, 06:30 PM) [snapback]417360[/snapback]</div>

My point was to show how your part about a CD being 1411 Kbps is not applicable to this conversation as it's not a format that people who listen to music on a digital format use anymore for audio playback. I don't think it's feasable anyone ever did, since before there was mp3 hard drives were not big enough to handle such large formats. The Mp3 format can reproduce sound that a CD normally doesn't have. I invite you to purchase a CD from a store with say, some orchestra on it and then find a copy of the same CD in a higher bitrate. You will hear more. Usually MP3's of around 320kbs are made from master copies that are given to publishing houses. Unless you are unfortunate enough to obtain a trans-code, meaning a mp3 file that was previously a lower rate cranked up to a higher rate, but all that is accomplished is a bunch of dead air data packets. You can use a free program such as dBpowerAMP to check for such a thing.


<div class='quotetop'>QUOTE(priusFTW @ Apr 3 2007, 06:48 PM) [snapback]417367[/snapback]</div>

You paid for a device that will give you the same audio quality with the iPod, so I'll try and figure out why you're not. I'm gonna fiddle with MP3 encoders and talk to Toyota and see what's up. It shouldn't be too hard since I have the same issue with this other 07 Prius. Is there any 06 Prius owners with the same issue?

All argument aside and asking officially, Mike.s did you get my PM about some steps I wanted you to check out for your issue?

 

<div class='quotetop'>QUOTE(Vagabond @ Apr 3 2007, 09:54 PM) [snapback]417371[/snapback]</div>

Wow. I don't know how to respond. That's just way, way, way wrong, and indicates a serious lack of knowledge about digital audio.

You claim people don't use CDs anymore, and don't think it feasible that people ever did. Ludicrous. (FYI, CDs are a digital format)

1411 Kbps audio (aka "CD quality") is entirely applicable to this conversation, because the OP was specifically comparing quality to exactly that. That's been pointed out several times, perhaps you weren't paying attention.

320 Kbps encoding on the iPod is not, and cannot be, better than CD quality, regardless of the source it was encoded from. The iPod ultimately plays everything back no better than 44.1 KHz/16 bit (CD-Audio native specification), because that's what it's DAC (output) hardware supports. You're claiming that by taking a high definition format, then using lossy compression, then returning what's left to CD rates/resolution can result in better sound than occurs on a CD, where the material has never been subjected to such abuse. Absolutely incorrect, and hard to believe that anyone could seriously believe that to be true. (Certainly no one knowledgable about the technology would.)

Now, it's certainly possible to take high definition source material, do lossy compression from that, and end up with better quality than if you did lossy compression from a CD. In fact, Apple does that for some of the tracks they sell through the iTunes Store. But that is NOT the same as ending up with better than CD quality, which will still be better.

I suppose it's also possible to encode high definition material for ultimate playback on better-than-CD players (i.e. a PC which supports 96KHz/24 bit playback), but this discussion is about playback from an iPod, which is limited to 44.1KHz/16 bit playback, so that's a red herring.

 

<div class='quotetop'>QUOTE(priusFTW @ Apr 3 2007, 07:29 PM) [snapback]417381[/snapback]</div>

Sure. I'll most likely getting started on it early next week. I was thinking about this weekend but it looks like I'll be goin' camping.

 

<div class='quotetop'>QUOTE(priusFTW @ Apr 3 2007, 05:17 PM) [snapback]417275[/snapback]</div>

Wow. Just... Wow.

So, thanks for even thinking to try this out. I just ran out and tried a few things with semi-interesting results. Unfortunately, I am way way too tired to really compare cd to ipod via dice to ipod via aux... I havea 6 week old baby w/ croup, so bare with me.

First of all PriusFTW is certainly not crazy here. I just played the Beach Boys's "California Girls" on my ipod via both methods. I chose this because I have listened to it several times trying to understand the nature of my tweeters which are totally screwed (blown/torn/bad/etc).

Two findings:
- via Aux, my tweeters sound significantly less screwed. While there was still a distorted almost static sound... it was subtle (lol, if distorted static can be subtle) compared to the DICE input where it just sounds... shredded.

- the bass is significantly fuller via Aux in. I played a 20hz -> 20khz sweep and you can certainly "feel" the low end better via Aux In.

I really need to get the sound meter do full frequency response to make heads of tails of this though. via cd at least, I know the fr graph had insane amounts of boost in bass/teble (a bit trough in the mids). Maybe via Aux In we get that eq effect from the head unit, but it gets by passed w/ the DICE?! If the DICE was had a flatter response, it would be hard to call that "bad".

The apparently increased distortion is more disturbing to me.

Sorry for the partial info -- if I get a chance tomorrow I will run better tests.

I can say this though -- this thread is seriously pushing me even further towards just ripping out the prius head unit in favor of a good after market w/ built in ipod integration and a reasonable frequency response.

 

<div class='quotetop'>QUOTE(Sillyboy @ Apr 4 2007, 12:11 AM) [snapback]417498[/snapback]</div>

Exact opposite. Remember, when you're using the 3.5mm on the iPod you're using the iPod's EQ first and the car's second. When it's plugged into the DICE it's sending the music not as an audio signal, but as pure data. The dice translates it into what the car can understand but it's still raw. The car is doing all the EQ work. That said, the DICE kit does have have it's own AUX jack with it's own simple built-in EQ.

Oh that would be a GREAT experiment. Plug in your iPod to the AUX jack in the DICE and see how it sounds for me. This experiment could go either way since I'll have to run the results by the engineers. And I need to take his 07 in and show the dealership the same thing, hopefully they'll be able to tell me more about any differences between an 04-05 unit and an 06, 07 unit. There's been others with 07's that have reported no problems with their sound.

Still no one with an 06 that can say they're having this issue? Or anyone with an 07 with the same thing and they have something other than a Coastal or DICE unit?

 

<div class='quotetop'>QUOTE(Vagabond @ Apr 4 2007, 08:14 AM) [snapback]417507[/snapback]</div>

No, that's not right. Normal iPods do not have digital audio output - it's just an analogue line out. In theory this line out should be higher-quality than the headphone output though.

(However, I understand that Gen 5 players do support some sort of digital output, I very much doubt DICE uses this facility, and I'm not even sure how it works; maybe it's USB).

 

<div class='quotetop'>QUOTE(KMO @ Apr 4 2007, 01:21 AM) [snapback]417512[/snapback]</div>

Sorry, maybe I should clarify myself more. The 3.5mm is most definitely a analog signal, and it's run through the iPod's EQ software first, then sent out the 3.5mm jack. The iPod doesn't know what you have it plugged into , it's just gonna treat everything like it was a pair of earphones and it's gonna clean up the sound on its own.

The data port on the bottom, it's not sending out audio to the DICE, digital or otherwise. It's just, data. You're right, the iPod does not send out a digital audio signal and we're not tapping into one with the DICE.

And now I really need to sleep. I meant to be in bed by 10 and instead I've been researching ipod stuff all night.