Car Audio Advice from the Audio Gurus: Use "Search thread" before posting a new Q!

[amit_mechengg]

Originally Posted by alto99

Please guys check the equalizers and SLA on your Pioneers.
I had similar problems with cassette player and aux input. Though the sources were not exactly same, I could tweak the equalizers differently to bring out similar sound outputs.

that is a solution that has to be done manually to match the quality of both sources. but IMHO keeping the settings same both should sound the same.

@SAM sir,
I agree with you but sir there is no data slip or anything as such. i think its the HU that reads the buffers from the usb and the cd differently.

Can someone please confirm with pioneer hows the conversion and why there is a difference?

[navin]

Originally Posted by amit_mechengg

but there is some difference as how the HU decodes from these sources of storage of media.
2. I have a mp3 disc some are will good amount of treble.
3. I have a 1 GB and 40 GB hitachi HDD which have same songs
4. cd then the tweeters on my JBL gto 937 play the high frequency sounds
5. when i play the same song from USB i feel the tweeters are not producing much sound.

Navin Sir, Please creep in.

1. I have no knowledge about USBs other than wondering why they did not just use/expand IEEE 802.3 instead.
2. every input source is processed differently. Tuner, USB, CD, why if you had a turntable you'd need a RIAA processor. This processing might be the reason.
3. my guesstimate it that since USB was "invented" by computer companies like Compaq, DEC, IBM, Intel, MS, NEC, and Nortel they wanted to reduce any aliasing errors so rollled of the HF as it was an easy solution. Data would nto care if the HF was there. Now you are using a data protocol to transfer music but the chips in the HU does not know that. They still believe that they are part of a data network. This is one reason why I wonder 8702.3 (ethernet was not used). Ethernet can handle gigabits today (and could handle 10Mbps at the time USB was invented - '94-95) 4 of the 8 wires on the RJ45 sockets were not being used anyway; they could have been used for power. Hey RCA beat out DIN and XLR so go figure.

[DerAlte]

Originally Posted by amit_mechengg

... i think its the HU that reads the buffers from the usb and the cd differently...

SNAFU!!!

Both the sources work asynchronous with the CODEC (the chip that decodes the mp3 stream; not the HU) and that is why the buffers! This is an OO system and the CODEC reads from the buffer, and reads either buffer the same way (Oy, CODEC is a preprogrammed chip, not a human; since pins are limited, the read bus is the same for both the sources).

Originally Posted by Sam Kapasi

But I repeat, data transfer rate cannot translate into poor audio quality. If the data transfer rate is slower than required, it will result in a skip (a data skip, if you will) it will NOT translate to poor sound quality.

Sam is absolute right.

If the buffers are not replenished on time (BUFFER UNDDERRUN), or NOT READ on time (BUFFER OVERRUN), bits of music passages go missing - resulting in the 'skips'.

Underrun can happen when the CD is scratched or there is too much noise affecting the USB transmission (too many retries).

Overrun can happen only if the mp3 file (correctly read off the source) has too many encoding errors in it, and the CODEC, instead of getting enough time to read the buffer, spends more time in trying to decode the stream.

If the decoded output from the CODEC does not contain enough of high frequencies, it is not the fault of the CODEC - but of the encoding of the file ("ripping").

[navin]

Originally Posted by navin

2. every input source is processed differently. Tuner, USB, CD, why if you had a turntable you'd need a RIAA processor....

I think this statement of mine is only partially correct. Comparing USB/CD to Tuner/Phono is not right. USB/CD are digital dit streams, TUner/Phono/Tape are analog.

Still I do believe that given that USB was developed by computer companies they might have tripped over the handling of frequencies over 10Khz.

[manson]

What is good single/double din DVD HU to get? Budget for HU 10-15K, gray market.
i do not want one with a screen upfront as it would distract the person driving, going to get a roof mounted 10" lcd for the rear view.
Have my gto 506 components from the honda for the front, and will be choosing between the 607c and the illusion electra speakers for the rear. Would be getting a JBL 604 amp for the speakers.
The setup is for an Innova.

manson.

[tush]

If at all you have a doubt that USB is the cause of sound quality replinishing there is another way you can compare.
Why not check it in your computer or say a laptop. Connect your earphones or say any external source of Music system to your computer but make sure its of good quality. Play the CD first and compare the same song by playing it from the USB stick in your PC. If you find any difference then probably there is a difference in SQ in playing from USB stick and you need not worry about thinking there is a problem with the HU. But if you find there is no difference then need to think why there is a difference when it comes to HU.

Note - Please make sure that it would be difficult to find a difference with earphones. But if you have a 3 way or a 2 way Speaker Music system connect that to your laptop or computer and then testify it and u will easily make out as u did in the car.

[praveen_v]

Originally Posted by navin

I think this statement of mine is only partially correct. Comparing USB/CD to Tuner/Phono is not right. USB/CD are digital dit streams, TUner/Phono/Tape are analog.

Still I do believe that given that USB was developed by computer companies they might have tripped over the handling of frequencies over 10Khz.

navin ji, all that is taken from the usb is a stream of binary data which is essentially same as in the case of cd's. Frequency is the rate at which this data is decoded and in that case the filtering must be done by the decoder or a filter circuit right??

[navin]

Originally Posted by praveen_v

navin ji, all that is taken from the usb is a stream of binary data which is essentially same as in the case of cd's. Frequency is the rate at which this data is decoded and in that case the filtering must be done by the decoder or a filter circuit right??

Exactly I think the IT companies tripped over the decoding/destructuring of this data assuming it would be data and not music.

Like I said, I know almost nothing about USB. So everything I state is assumption.

[reignofchaos]

Maybe the USB input has a cheap analog stage attached to it and doesn't use the main DAC? Can't think of any other reason. Or maybe the user has uncompressed audio on CD and compressed MP3 on USB.

[razor4077]

There are a few similar posts to my query, but couldn't really find an answer to it.
The lights in my Lancer (headlights, fog lights, dashboard) flicker when I play a song with heavy bass in it. The flickering goes away if I reduce the subwoofer level through my HU.
The setup is as follows:
Alpine CDE 9881 HU
JBL GTO 75.4 amp
JBL GT4-12 sub in a sealed box
Illusion Electra EL 6.1 front component spkrs
Pioneer TS-A6982S coaxials rear fills

The amp runs the front comps and the sub (bridged), while the rear fills are run off the HU.

- I am using a Stinger SWK8RS amp wiring kit, which includes a Stinger Pro Series 8 Gauge power wire.
- The battery is a new Bosch Silver

The headlights sort of "keep to the beat" of the songs when the sub is set on high. Is there any setting on the amp that can help eliminate this? Else, what could be the resolution?

[navin]

Originally Posted by razor4077

The headlights sort of "keep to the beat" of the songs when the sub is set on high. Is there any setting on the amp that can help eliminate this? Else, what could be the resolution?

If it disturbs you get a 1F cap but be warned that this cap will do almost nothing to your ICE. Just get a good cap not a "challu" one.

[razor4077]

Originally Posted by navin

If it disturbs you get a 1F cap but be warned that this cap will do almost nothing to your ICE. Just get a good cap not a "challu" one.

So a cap is the only way? Not sure what you meant by 'this cap will do almost nothing to your ICE'. Do you mean it won't enhance the sound in any way? If so, then I am aware of this.
Apart from the disturbance factor, is there any potential risk in cases like mine?

Finally, could you suggest a good 1F cap... brands/prices?
Thanks.

[amit_mechengg]

is there any way to directly add a capacitor on the alternator coil which supplies current to the sparkplugs? i remeber one installer telling me that if i want to get rid of the alternator whine add capacitor to the coil and earth the other end of capacitor to the body.
i am totally clueless about this.

secondly i have heard about whines only in pio hu's. why not alpines or blaus ?

[manson]

Whatever happened to my HU query!!

manson.

[speedzak]

secondly i have heard about whines only in pio hu's. why not alpines or blaus ?

Our Razor man himself uses an Alpine.
The whine isn't mostly due to HU. The wiring happens to be a big culprit in most cases.