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Discussion Starter #1
Hi guys,

I purchased a 2014 Volt in December, and I've noticed over the last month that sometimes when I'm playing music via Bluetooth, that it sounds flat. I can't quite reliably reproduce this problem: sometimes it seems to fix itself, and other times I could swear I hear it while playing CDs. Play/pausing it doesn't help (in case it's a slowly filling buffer), and the pitch-bending is variable (i.e. it fluctuates between flat and being on-pitch). I'm a musician, and this does bother me quite a bit. Is anyone else having this issue?

2014 Volt, MyLink radio
Nexus 5 phone

Thanks!
 

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I have noticed sound variation during the first few minutes, when I assumed that the system is busy with startup tasks such as talking with my address book and looking up song information, and also some screen/ button lockups during the same period; but have not noticed this on an ongoing basis. I am also bothered when one of my teenagers gets in the car and his or her Music player songs all seem to have been recorded at a low sampling rate. They of course, will tell me that I've lost too much high frequency hearing to know the difference between a 70 khz sample and a 300 khz sample.... maybe so....
 

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Discussion Starter #3
That's true, it could be a sampling rate problem. The curious thing is that I have a pair of Bose Bluetooth headphones that I listen with at work (from the same Nexus 5) and don't notice any pitch-bending.

I know I do have a large address book... perhaps that's tying up the Bluetooth data stream? That actually seems somewhat plausible to me.
 

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Keep in mind the tone settings need to be set independently for each music source.
 

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Not sure if your using i.e.pandora or such but make sure that any options such as pandora has does the higher bit rate/higher quality feed as it seems it allows for depending on your network connection as i.e. 3g, 4g, 4glte, etc...unless your playing from your i.e. phone or pad directly to the unit without streaming....just my obervation playing with pandor either thru bluetooth or directly to the pandora built inapp on the volt from my pandora appl on my phone.
 

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Discussion Starter #6
I've tested the address book hypothesis and that doesn't seem to be the problem. I unpaired on both the Volt and from my phone, re-did pairing, and forcibly disallowed the Volt from connecting to address book, call log, or SMS log. No difference, problem still occurs.

I then got an app that is a combo tone generator and tuner. Lo and behold, the Volt is bending pitch by almost a half-step in either direction and it fluctuates. I'm taking it to the dealer next week to see if they can fix it (software update etc).

@Joule: I've already checked Tone setting: EQ is manual and flat.

@imanjunk1963: It is playing from local disk. I don't encounter this problem on any other Bluetooth audio playback device I own.
 

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Hi guys,

I purchased a 2014 Volt in December, and I've noticed over the last month that sometimes when I'm playing music via Bluetooth, that it sounds flat. I can't quite reliably reproduce this problem: sometimes it seems to fix itself, and other times I could swear I hear it while playing CDs. Play/pausing it doesn't help (in case it's a slowly filling buffer), and the pitch-bending is variable (i.e. it fluctuates between flat and being on-pitch). I'm a musician, and this does bother me quite a bit. Is anyone else having this issue?

2014 Volt, MyLink radio
Nexus 5 phone

Thanks!
Hi THX,

I have the exact same issue, albeit in my HSV (Holden Special Vehicles (Australia) GTS. Being a fellow musician I started to hear this shortly after taking ownership of my vehicle last weekend. For mine, it seems that the first minute or so of music is fine, and then the fluctuation in pitch begins and like yours, it goes from pitch-perfect to slightly flat. As I have no other sources with Bluetooth I can't do a comparison, but have tried restarting the phone but to no effect. Going via USB does not reproduce the issue and it plays fine... Will try and get another bluetooth device from someone so I can test as a comparison.
 

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Discussion Starter #8
Oops, thought I had already replied back with the results.

Took it to the dealership, explained the problem and demonstrated my experiment to one of the service techs. They initially brushed it off as having a flat EQ (which I was somewhat peeved about) until I showed the tuner test. The guy said he would try to raise the issue with GM, but I'm not too hopeful.

I talked to a friend of mine who is an expert on digital audio, and he thinks it might be an issue with the codec that the car is using. Turns out that the Bluetooth audio standard goes through a codec negotiation process. Every device is expected to support a baseline codec that has terrible audio quality, but the high-end controllers understand MP4 etc.

My speculation (being a software engineer as my day job) is that it's a combination of a bad codec with a improperly scheduled decoding process. I also did a bit of sleuthing through the open source licenses included in the car. The radio runs QNX, a realtime OS, which should be able to handle audio properly, but there's something not quite right. I wish GM would issue a software update, but I don't think that's going to happen.

I have resigned myself to using the 3.5mm jack. USB should also work, as you've said.
 

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USB

Hi -

New Volt owner and fellow musician / audio technician. I noticed this pitch fluctuation immediately - and it's horrible. Sounds like an old tape that's been played too many times, or a record.

While I cannot confirm the codec issue as a possible culprit, I can confirm that this also happens with the USB. I haven't tried the 3.5mm yet.

Anyone find any solutions?
 
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Hi -

New Volt owner and fellow musician / audio technician. I noticed this pitch fluctuation immediately - and it's horrible. Sounds like an old tape that's been played too many times, or a record.

While I cannot confirm the codec issue as a possible culprit, I can confirm that this also happens with the USB. I haven't tried the 3.5mm yet.

Anyone find any solutions?
Hi herkemer2,

Welcome to the forum and congratulations on your new purchase! This fluctuation you are referencing does not sound pleasing to the ears. I’m sorry you have been stuck listening to that. Has your Volt Advisor introduced himself or herself to you yet? If you have any questions or would like me to notify your advisor on your behalf, please let me know. You can send me a private message with your VIN and contact information and I’ll have them give you a call. Aside from the pitch fluctuation, are you enjoying your new EV?

Katie O.
Chevrolet Customer Care
 

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I've had this same issue, and I too am a musician, so it drives me nuts!

For me it has been intermittent, which may support your hypothesis that it's a codec issue. So far I've only noticed it on one particular mp3 file.. just looked at it and it's encoded mp3 at 128bps. I don't remember what software I used to encode it.

I'll try coding it with ogg vorbis and see if that solves the issue.
 

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Just to provide an update - this issue is not limited to the Volts. It also occurs in Cruze and Commodores/HSV (Australian models) cars with 2014 and later MyLink systems.

This seems to be a fundamental issue with the underlying Panasonic system - but GM have now confirmed it is a "characteristic" and not something that Panasonic considers to be a problem. There are no plans to resolve this as the position of GM is that nothing is broken and it is not a defect.

Pretty sure that any other audio system manufacturer would be considered crazy if they came out and stated that an audio system messing with music pitch to make it sound as bad as it does is "normal" behaviour. Why GM won't just work with Panasonic and fix this clear software issue is beyond me :)

To me, this is deeply disappointing and frustrating seeing as GM in Australia couldn't care less about fixing this defect and continually brush it off as being normal and something affected owners should stop complaining about as there is nothing defective with music sounding like this.

@GM Customer Care team - would love to discuss this further so we can come up with a resolution for all affected owners. All of the years of great GM service that I'm sure many of us have had seems to be destroyed by this global problem that nobody is willing to take ownership and fix within GM and Panasonic.

The very least that GM could do is to ensure all new Cruze, Commodore and Volt owners are aware that MyLink is defective and will alter Bluetooth/USB music output from iPhone/iPad and Android devices so it sounds out of tune so that they can make informed purchase decisions. This is a luxury sadly not available to those of us who have already purchased and are now stuck with defective vehicles with no potential of resolution seeing as GM/Panasonic won't accept this as being a fault, but instead a "characteristic".
 

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Anyone had any success in solving this problem?
I've experienced this problem streaming music from my iPhone 5s to my 2015's (Bose) system. The problem is reminiscent of a turntable with a bad case of "wow and flutter" and appears to be consistent across all file types (MP3, AAC, etc), and perhaps even Pandora streams.

My solution: I've abandoned Bluetooth music streaming in favor of a music-fllled thumb drive plugged into the USB port. This seems to be unaffected by the problem.
 

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My new 2015 Volt with the stock audio system (not Bose) has this same issue, and it's driving me crazy. I can reproduce by just running a sine wave generator on my iPhone 6 Plus. The pitch bends by almost a half step about once a second. You don't have to be a musician to be bothered by it. It sounds like a crappy tape player.

Any updates on this? Has anybody managed to fix the issue? I'll try an aux cable later today when I have time. I'm also going to try it with different phones.
 

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While this issue is not fixed, thank goodness for this thread. I thought I was insane! I have the same problem on my MY2015 Volt with Bose. I describe the effect as a stretched tape or warped vinyl record. I experience the sound warping on both bluetooth and usb with both music through iTunes and Spotify.
 

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Sounds like a sample rate mis match. Since most CD's are recorded at 44.1khz it might be that the car is playing back at 48khz? Or perhaps the reverse?

This is just bizarre. Never heard of this issue with any other digital player.
 

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Whew, nice to see I'm not the only one with a bad 2015!

I experimented today after work. I used two iPhone 6 Pluses, both up to date with the latest non-beta iOS (8.3). I don't have any Android devices lying around, but based on other posters, I'm assuming it doesn't work either.

I was able to reproduce the pitch bend over both Bluetooth and USB, using both Spotify and the Signal Generator app. Signal Generator is a great way to demonstrate the issue, because the bend it's plain as day with a pure sine wave. Set the frequency at about 470 Hz and you can't miss it. Over both protocols, it takes about 30 seconds after connecting for the bend to start. Before that, the audio sounds fine. The magnitude of the bend seems about the same to me over both protocols. I measured it as about 10 Hz swing, repeating about once per second.

I toggled just about every option I could find in the config menus on the head unit. I tried resetting the radio to factory defaults and then resetting the whole unit to factory defaults. I rebooted both phones multiple times. I powered the car on and off. I drove in circles around the parking garage. I accelerated and braked. I moved the position of the phones around the cabin. I toggled Bluetooth on and off. I unplugged and re-plugged the USB. I adjusted the volume both on the phone and on the car stereo. Nothing changed at all, no matter what I tried.

The good news is that the aux cable does NOT have the pitch bend issue. The bad news is that I can't seem to use aux out from my phone when Bluetooth is connected. This means I have to choose between listening to music or taking calls. Not to mention you can't use any of the cool features over aux, such as controlling the music from the dash, album art, track/artist/album, etc.

I'm going to make an appointment with the dealer this week but I don't have my hopes up. Previous posters made it sound like GM has acknowledged the issue and they are not going to fix it. I hope that's not the case. We don't even have the option to install an aftermarket stereo.

I'm real bummed out about this :(

PS -- interesting thought about the sample rate. You'd think every audio device made since like 2000 would support both 44.1 and 48 kHz sample rates... but at this point, nothing would surprise me.
 

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PS -- interesting thought about the sample rate. You'd think every audio device made since like 2000 would support both 44.1 and 48 kHz sample rates... but at this point, nothing would surprise me.
The hardware may indeed support 44.1 and 48 khz sample rates... But the logic & firmware that decides which one to select may be wrong.

My 2014 Volt seems to work OK with my iPhone 6. I am not hearing pitch shifts. It's a very bizarre behavior you guys are reporting. Very sad. Have you tried plugging in the USB cable? Does it play correctly with an aux USB cable connected?

I usually plug in a USB cable so my phone is charging anyways...
 

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The tech at the dealership couldn’t do anything about it. All software was up to date. He said the notes from the work order would be forwarded to GM, but to not expect a fix and to use an aux cable as a permanent workaround.

The tech was a guitarist, and could clearly hear the distortion. We tried it out on his Android phone on a few Foo Fighters songs, and he described the effect: “that chord is shifting between A and A flat”.

Is there any way to contact GM directly about this?


@Fulgerite: Bluetooth and USB both have the issue. A 3.5mm aux cable does not.
 
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