Help me understand this car stereo sound quality problem please?
December 24, 2023 8:48 AM Subscribe
I finally got fed up with the lack of AUX input on my elderly car's factory stereo, so Car Sound Guy installed a new stereo last week. It's not performing satisfactorily, and he has offered to remedy the situation (he's lovely, so far), but I want to be prepared to discuss it intelligently on Tuesday, and I'm a newb about audio. Details inside.
2003 4runner LE has "OK" speakers - JBL 'upgraded' factory sound system. They aren't damaged as far as I can tell but you never know. According to Crutchfield they are "low impedence". Car Sound Guy installed an Alpine ILx-W670 head unit. The sound isn't right (and I hate the UI). He has offered to replace it with a different one that I pick out, but I need to be able to use the right words to ask questions and understand his answers.
I assume he is using my existing amplifier, although there is a blurb on Crutchfield for this car/stereo combination about "If you plan to bypass the factory amp, we recommend replacing your vehicle's low-impedance speakers with standard 4-ohm aftermarket speakers to avoid damaging your new radio. However, if you want to keep your factory speakers, you'll need to add a small aftermarket amplifier." Maybe he didn't do that right.
Volume info: My car has some road noise, meaning I need to be able to listen with volume on the louder side to clearly hear audiobooks. This volume turns out to be 23 (out of 35? on this head unit) with the audiobook I tested yesterday. For reference, stopped with engine off, this volume is just past where my ears say "ugh that's just a little too loud for comfort", and I'm a quiet music listener. For second reference point, before this, I was able to listen to audiobooks at this volume no problem with a $64 portable bluetooth speaker sitting on the console. So, we're not talking super loud.
Use case: I will be using WIRED Apple CarPlay from an iPhone 11 with latest ios to play audiobooks (Libby) and music (ripped and purchased mp3s from Apple music app). Both of these worked fine (no sound quality degradation) on my $64 portable bluetooth speaker at the appropriate volume, although definitely not the greatest overall experience. Thus the new stereo. I'm currently testing it at a flat equalizer profile and the fade/balance centered, although I did test moving the sound around to see if one particular speaker was causing the problem (it's not).
Here's the issue:
When I play a radio station at that volume, it sounds fine. Not "Wow!", but a solid "No complaints" for both music and human speech. However, when I play music from my iphone through Wired Car Play at that volume, the treble sounds extremely "fizzy" or "snowy", like static on a tv. Not constant fizz, but fizz synced to the volume peaks of the music. And when I play an audiobook, it sounds similar but much worse.
Question 1: Is this problem explainable by him bypassing my amp and not installing the "small aftermarket amplifier" in the Crutchfield blurb?
Question 2: Is this difference between Wired CarPlay and Radio sound qualities explained by science?
Question 3: Is this a known/common problem with Wired CarPlay? The only complaints I find online are about bluetooth CarPlay.
Question 4: What's the right word for the "fizz" and what causes it? Why no fizz on radio signal? I don't understand signal amplification or gain or anything about speakers. Any quick nuggets you can share about that to help me understand the physics?
Question 5: Is the Fizz likely to be caused by my "Not the greatest but not trash" speakers? I expect Car Sound Guy will first offer to sell me upgraded speakers as the solution. Do I stand my ground with "You should be able to make it work with these speakers" or is upgrading speakers a direction that I might have to/want to go? If these speakers could play CDs just fine at volume in 2003, why shouldn't they be able to do this job now?
(Also there are issues with phone audio and mic but I think I can explain that part. "I can't hear my mom and she can't hear me" pretty much covers that one, lol.).
Thanks so much in advance for your help!
2003 4runner LE has "OK" speakers - JBL 'upgraded' factory sound system. They aren't damaged as far as I can tell but you never know. According to Crutchfield they are "low impedence". Car Sound Guy installed an Alpine ILx-W670 head unit. The sound isn't right (and I hate the UI). He has offered to replace it with a different one that I pick out, but I need to be able to use the right words to ask questions and understand his answers.
I assume he is using my existing amplifier, although there is a blurb on Crutchfield for this car/stereo combination about "If you plan to bypass the factory amp, we recommend replacing your vehicle's low-impedance speakers with standard 4-ohm aftermarket speakers to avoid damaging your new radio. However, if you want to keep your factory speakers, you'll need to add a small aftermarket amplifier." Maybe he didn't do that right.
Volume info: My car has some road noise, meaning I need to be able to listen with volume on the louder side to clearly hear audiobooks. This volume turns out to be 23 (out of 35? on this head unit) with the audiobook I tested yesterday. For reference, stopped with engine off, this volume is just past where my ears say "ugh that's just a little too loud for comfort", and I'm a quiet music listener. For second reference point, before this, I was able to listen to audiobooks at this volume no problem with a $64 portable bluetooth speaker sitting on the console. So, we're not talking super loud.
Use case: I will be using WIRED Apple CarPlay from an iPhone 11 with latest ios to play audiobooks (Libby) and music (ripped and purchased mp3s from Apple music app). Both of these worked fine (no sound quality degradation) on my $64 portable bluetooth speaker at the appropriate volume, although definitely not the greatest overall experience. Thus the new stereo. I'm currently testing it at a flat equalizer profile and the fade/balance centered, although I did test moving the sound around to see if one particular speaker was causing the problem (it's not).
Here's the issue:
When I play a radio station at that volume, it sounds fine. Not "Wow!", but a solid "No complaints" for both music and human speech. However, when I play music from my iphone through Wired Car Play at that volume, the treble sounds extremely "fizzy" or "snowy", like static on a tv. Not constant fizz, but fizz synced to the volume peaks of the music. And when I play an audiobook, it sounds similar but much worse.
Question 1: Is this problem explainable by him bypassing my amp and not installing the "small aftermarket amplifier" in the Crutchfield blurb?
Question 2: Is this difference between Wired CarPlay and Radio sound qualities explained by science?
Question 3: Is this a known/common problem with Wired CarPlay? The only complaints I find online are about bluetooth CarPlay.
Question 4: What's the right word for the "fizz" and what causes it? Why no fizz on radio signal? I don't understand signal amplification or gain or anything about speakers. Any quick nuggets you can share about that to help me understand the physics?
Question 5: Is the Fizz likely to be caused by my "Not the greatest but not trash" speakers? I expect Car Sound Guy will first offer to sell me upgraded speakers as the solution. Do I stand my ground with "You should be able to make it work with these speakers" or is upgrading speakers a direction that I might have to/want to go? If these speakers could play CDs just fine at volume in 2003, why shouldn't they be able to do this job now?
(Also there are issues with phone audio and mic but I think I can explain that part. "I can't hear my mom and she can't hear me" pretty much covers that one, lol.).
Thanks so much in advance for your help!
Best answer: i would also try, as a troubleshooting step, connecting the phone audio output directly to the head unit over bleutooth and listen if the distortion is present in that mode the same as in wired carplay.
posted by glonous keming at 9:51 AM on December 24, 2023
posted by glonous keming at 9:51 AM on December 24, 2023
Best answer: What is the physical plug you’re using?
USB?
The fuzz varying with the audio makes me suspect a grounding problem, but I would expect CarPlay audio over USB to be in the digital domain. Maybe the digital to analog conversion is happening in a CarPlay adapter external to the head unit, to which it sends a line level.
posted by snuffleupagus at 10:30 AM on December 24, 2023
USB?
The fuzz varying with the audio makes me suspect a grounding problem, but I would expect CarPlay audio over USB to be in the digital domain. Maybe the digital to analog conversion is happening in a CarPlay adapter external to the head unit, to which it sends a line level.
posted by snuffleupagus at 10:30 AM on December 24, 2023
Response by poster: Some answers (went and tested):
Check whether lowering the output level on the phone changes the amount of distortion. Nope. Iphone volume button doesn't affect the speaker volume or the amount of distortion in wired carplay. Lowering the speaker volume at the head unit (say down to 18-19 comfortable listening with engine off) does eliminate the distortion.
When changing from radio to aux, do you need to adjust the volume setting on the car stereo more than just a bit to get the same sound level from the speakers? Not really; switching from good volume radio to good volume CarPlay involves bumping volume up one level only.
I would also try, as a troubleshooting step, connecting the phone audio output directly to the head unit over bleutooth and listen if the distortion is present in that mode the same as in wired carplay.
This sounds the same, albeit I have to turn the speaker volume up to 25/26, rather than 23 for wired. The 25/26 distortion on BT is the same as the 23 distortion on wired. [This is with iphone internal volume at max].
What is the physical plug you’re using? USB-A to lightning. Judging by the online picture, the head unit seems to have a USB-A female connection, and comes with a 3' male to female extension cable, which my guy installed with about a 1 foot pigtail, leaving a USB-A female connector for me to plug my lightning cable into. I tried a few different lightning-usb cables and they all sounded the same.
posted by bluesky78987 at 10:55 AM on December 24, 2023
Check whether lowering the output level on the phone changes the amount of distortion. Nope. Iphone volume button doesn't affect the speaker volume or the amount of distortion in wired carplay. Lowering the speaker volume at the head unit (say down to 18-19 comfortable listening with engine off) does eliminate the distortion.
When changing from radio to aux, do you need to adjust the volume setting on the car stereo more than just a bit to get the same sound level from the speakers? Not really; switching from good volume radio to good volume CarPlay involves bumping volume up one level only.
I would also try, as a troubleshooting step, connecting the phone audio output directly to the head unit over bleutooth and listen if the distortion is present in that mode the same as in wired carplay.
This sounds the same, albeit I have to turn the speaker volume up to 25/26, rather than 23 for wired. The 25/26 distortion on BT is the same as the 23 distortion on wired. [This is with iphone internal volume at max].
What is the physical plug you’re using? USB-A to lightning. Judging by the online picture, the head unit seems to have a USB-A female connection, and comes with a 3' male to female extension cable, which my guy installed with about a 1 foot pigtail, leaving a USB-A female connector for me to plug my lightning cable into. I tried a few different lightning-usb cables and they all sounded the same.
posted by bluesky78987 at 10:55 AM on December 24, 2023
Best answer: There is a distinct possibility here that this has to do with the settings on your iPhone and not the new head unit, amplifier or speakers.
You are using Apple Music to test and not another app, yes? I'd go to Settings -> Music on your iPhone, turn off Dolby Atmos, turn off the EQ, turn off Sound Check, and set Audio Quality to Lossless (except for Cell Streaming, set to High Quality), then test again.
posted by eschatfische at 11:00 AM on December 24, 2023
You are using Apple Music to test and not another app, yes? I'd go to Settings -> Music on your iPhone, turn off Dolby Atmos, turn off the EQ, turn off Sound Check, and set Audio Quality to Lossless (except for Cell Streaming, set to High Quality), then test again.
posted by eschatfische at 11:00 AM on December 24, 2023
Best answer: Probably not an issue with the physical connection then. Could still be a problem with the digital to analog conversion within the head unit.
Do you have another Bluetooth source you can connect to the stereo to test it with? Ideally not an iPhone or iPad.
posted by snuffleupagus at 11:02 AM on December 24, 2023
Do you have another Bluetooth source you can connect to the stereo to test it with? Ideally not an iPhone or iPad.
posted by snuffleupagus at 11:02 AM on December 24, 2023
Response by poster: Ok, Thanks everybody, tested a few more things:
You are using Apple Music to test and not another app, yes? I'd go to Settings -> Music on your iPhone, turn off Dolby Atmos, turn off the EQ, turn off Sound Check, and set Audio Quality to Lossless (except for Cell Streaming, set to High Quality), then test again. Yes, testing with Applie Music (but not streaming - from music on my iphone). EQ was already off. I turned off Sound Check but no change. No audio quality setting available, maybe because I'm not streaming?
Do you have another Bluetooth source you can connect to the stereo to test it with? Ideally not an iPhone or iPad. All I have is a MacBook Air. I pulled up the same song (Akon - Beautiful) on youtube. Put that on BT and the sound was fuller and nicer and maybe a hair louder than playing the mp3 on my phone, but the distortion was still there.
I suppose one thing to try at the car place will be to plug my phone into the Car Sound Guy's stereo and see if it's different.
posted by bluesky78987 at 11:26 AM on December 24, 2023
You are using Apple Music to test and not another app, yes? I'd go to Settings -> Music on your iPhone, turn off Dolby Atmos, turn off the EQ, turn off Sound Check, and set Audio Quality to Lossless (except for Cell Streaming, set to High Quality), then test again. Yes, testing with Applie Music (but not streaming - from music on my iphone). EQ was already off. I turned off Sound Check but no change. No audio quality setting available, maybe because I'm not streaming?
Do you have another Bluetooth source you can connect to the stereo to test it with? Ideally not an iPhone or iPad. All I have is a MacBook Air. I pulled up the same song (Akon - Beautiful) on youtube. Put that on BT and the sound was fuller and nicer and maybe a hair louder than playing the mp3 on my phone, but the distortion was still there.
I suppose one thing to try at the car place will be to plug my phone into the Car Sound Guy's stereo and see if it's different.
posted by bluesky78987 at 11:26 AM on December 24, 2023
Best answer: I've had a very very similar problem putting a new stereo in the same era of truck. I traced the issue back to a not-good-enough ground due to how the stereo wiring harness wasn't directly grounded, and expected the stereo mounting bracket to be the ground. I ran a little wire from the stereo to the dashboard frame and it markedly improved. To get a "wow that's great!" i would have had to run a dedicated ground wire to the stereo, which wouldn't have really been hard, but i was too lazy to ever do.
I would have the stereo guy check the pinout of both the cars connector, and the adapter kit they're using with the stereo. I've literally seen it twice now that the adapter had an "idk figure it out" ground wire hanging off of it with no equivalent in the cars harness.
posted by emptythought at 3:03 PM on December 24, 2023 [3 favorites]
I would have the stereo guy check the pinout of both the cars connector, and the adapter kit they're using with the stereo. I've literally seen it twice now that the adapter had an "idk figure it out" ground wire hanging off of it with no equivalent in the cars harness.
posted by emptythought at 3:03 PM on December 24, 2023 [3 favorites]
Response by poster: Following up in case anybody else ever has this issue. Car Audio Guy ended up fixing it by changing out the "Audio Module". He had to try three different ones but eventually one worked.
posted by bluesky78987 at 6:06 AM on December 28, 2023 [1 favorite]
posted by bluesky78987 at 6:06 AM on December 28, 2023 [1 favorite]
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- in the radio receiver
- the amp
- the speakers.
This leaves the aux input. And the 'fizzy' distortion suggests there's a signal level mismatch between what the iPhone puts out and what the aux input expects. It's quite possible to fix this with an attenuator between the phone and the input, but the first thing to check is whether lowering the output level on the phone changes the amount of distortion. When changing from radio to aux, do you need to adjust the volume setting on the car stereo more than just a bit to get the same sound level from the speakers?
posted by Stoneshop at 9:45 AM on December 24, 2023 [2 favorites]