Head unit supporting USB audio?

[casm]

Is anyone aware of a head unit that supports USB audio input?

I'm not talking about the ability to plug in a USB thumb drive, etc. and play MP3s from it - what I'm referring to is the unit's ability to accept audio output over USB from <insert device here>. There are USB -> RCA adapters out there, but figured I'd ask if anyone was aware of something that could just do it directly.

Note that I'm not asking this in reference to a specific device - it's more of a general question prompted by seeing a number of them advertising iPod audio over USB. If that's the same as USB audio from another device, that would also be handy to know.

 

[bmyohn]

If I understand what you're saying, you want something that you can basically take your iPod and plug it into the head unit via the USB cable and play music off of? (I'm not overly tech savy so I apologize if I misunderstood). But I just picked up this Kenwood head unit from Best Buy that I can take my iPod/Droid and plug it in via aux cable or usb cable and stream music off of. It is also HD radio capable, bluetooth ready, sat. radio capable, etc. For the money its not a bad unit and Kenwood makes a pretty solid/reliable product. It works great in my tow rig although the bluetooth setup isn't great but does the job.

http://www.bestbuy.com/site/Kenwood+-+50W+x+4+MOSFET+Apple%26%23174%3B+iPod%26%23174%3B-/Satellite+Radio-/HD-Ready+In-Dash+CD+Deck/9760697.p?id=1218168620295&skuId=9760697

 

[Hellbent]

i have that same(i believe) radio in the mj. it plays from thumb drives and/or my iphone plugged directly in via usb.

 

[cheapcherokee93]

I too have the same head unit in my XJ, its a great unit! it does indeed stream ipods/iphones, and i believe USB flash drives as well. one thing i find handy sometimes is the "ipod mode" function, which plays and charges the ipod through the car speakers, but also lets you scroll through music on the actual ipod, instead of painstakingly going through it on the head unit.

 

[casm]

If I understand what you're saying, you want something that you can basically take your iPod and plug it into the head unit via the USB cable and play music off of?

Nope, that's not it. iPod connectivity is easy to resolve (I've had an Alpine unit in there for a few years that handles that) as is playback of files from a USB key or other mass storage device, but this is rather different.

USB can carry an audio stream from a device that is analogous to, say, a line out. If that device is plugged into another device capable of reading that audio stream, it's essentially equivalent to tying two audio components together via an RCA cable except that the connection is digital from end-to-end.

The ultimate goal is to be able to plug one end of a USB cable into my device, the other end into the head unit, and listen to audio from the device through the head unit; this should also make it possible to charge the device over the same cable while it's connected to the head unit. Patching analogue audio from the device into the head unit is not something I want to do in this case, BTW.

(I'm not overly tech savy so I apologize if I misunderstood).

No worries. I'm fairly familiar with USB, but doing audio over it is new to me. I may not be describing this as accurately as I could be as a result, and the stereo manufacturers not being completely clear on their units' capabilities probably isn't helping.

 

[XJLI]

for what?

you cant carry usb audio without code to interface to the device. for example.. you cant just plug in a zune or an archos to without programming to read the it. the exception is obviously a flash drive since its just a storage device.

 

[casm]

for what?

Any existing device that supports it :dunno: The specific example I had in mind was my phone, but it could be anything that supports audio over USB. I'd really prefer to not focus on that for right now and stick to finding if there's a head unit that does what I'm looking for, though - if there isn't, I already know what my alternative is.

you cant carry usb audio without code to interface to the device. for example.. you cant just plug in a zune or an archos to without programming to read the it.

I could be misunderstanding something here, but the USB audio device class specification specifically provides a mechanism that sounds like it provides a way to accomplish what I'm looking to do as part of the base USB spec (ref. pt. 2 of this document).

That doesn't mean that a manufacturer couldn't come up with their own way of interfacing their device over USB, but rather that as long as that base method of audio connectivity is supported and the receiving device supports playback of the audio stream, it should be possible to do it. Apparently it's a pretty common method of connecting things like USB headsets, so it's not like it's voodoo to implment; I just need to find a head unit that can support it.

the exception is obviously a flash drive since its just a storage device.

Sure, which is fine for block access of files, but I'm looking at sending streaming audio as data to the head unit.

 

[RAM-ROD]

Just to throw something else into the mix...i was using my Thub drive in my head unit with zero problems. but Apple just decided this month to star encoding music files now like video's ...MP4A and MP4P. So make sure if your are buying songs off I-tunes you switch your settings on your computer back to MP as the sofware updated it's self to MP4. The problem with the MP4 files is you can only play them from an Apple procuct like an I-pod or I-phone. You can play them on your computer with Microsoft player but they will not transfer to the thumb drive. I liked using my thimb drive but it looks like i am back to using my I-pod plugged into my head unit being a bunch of music my wife just bought from i-tunes is the protected MP4P files format.

 

[RAM-ROD]

crap my typing sucks but you will get the idea

 

[asp]

I'd like to help... But I'm sort of confused. I think the problem at hand is more simple than the posts in this thread make it out to be. Caveat: I know you're specifically not talking about the iPod, but it's a popular example of something that streams data via USB 2.0 - so I'm going to use it.

You mentioned you have an Alpine - so do I. In fact, I've owned 2. My first one was a CDE 9881 that I sold to a member here. That one charged the early gen iPods that used firewire for charging. New iPods only charge through USB 2.0. I ended up with a new iPod and a new car with steering wheel controls - so I wanted a new head unit. My current head unit is an Alpine CDA 117 (& here) and it has a USB 2.0 cable coming out the back of it that I routed to the armrest. The end of that cable is a female USB cable. You could plug any usb-device into it and it will charge and talk to it. I have a short usb-iPod connector that it came with. I can navigate the iPod through the head unit while it charges. The HU also supports Zune and a USB stick.

So maybe I misunderstood what you were asking, but I think the HU in my VW will work for you.

 

[casm]

Just a quick general note for anyone reading this: USB thumb drives and other storage devices are not suitable for what I am looking to accomplish here. Please save yourself the effort of suggesting them; they simply don't support the features I want to use. Thanks.

Caveat: I know you're specifically not talking about the iPod, but it's a popular example of something that streams data via USB 2.0 - so I'm going to use it.

Understood.

You mentioned you have an Alpine - so do I. In fact, I've owned 2. My first one was a CDE 9881 that I sold to a member here. That one charged the early gen iPods that used firewire for charging.

I'm on about my 5th or 6th, and if you never had a KCA-420i attached to your head unit, you missed out on a fun time. God, did that thing suck. Back on topic:

New iPods only charge through USB 2.0. I ended up with a new iPod and a new car with steering wheel controls - so I wanted a new head unit. My current head unit is an Alpine CDA 117 (& here) and it has a USB 2.0 cable coming out the back of it that I routed to the armrest. The end of that cable is a female USB cable. You could plug any usb-device into it and it will charge and talk to it. I have a short usb-iPod connector that it came with.

OK. I see where you're going with this, but let me explain where the unknown is for me first. More:

I can navigate the iPod through the head unit while it charges. The HU also supports Zune and a USB stick.

That it can control these devices is fine, but in order to do so it has software on board to accomplish that. However, device control isn't something I'm looking for in this example - it would actually be preferable for the attached device to retain its own control.

What I am talking about is literally equivalent to a line in via USB, which the USB standard apparently supports. For all I know, this may be the method by which the iPod/Zune sends audio data down to the head unit; it would make sense for them to do so. It's this method that I want to use.

So maybe I misunderstood what you were asking, but I think the HU in my VW will work for you.

The issue I can see is that even if it is capable of doing audio over USB, that functionality may not be activated unless an iPod or Zune (specifcally) is connected - so just plugging any old device in may not work. However, I'm going to be near one of Crutchfield's stores in the next couple of days, so I'll bring the phone and a USB cable with me and give it a shot.

 

[asp]

I'm on about my 5th or 6th, and if you never had a KCA-420i attached to your head unit, you missed out on a fun time. God, did that thing suck.

Thankfully, I missed out. :looney:

That it can control these devices is fine, but in order to do so it has software on board to accomplish that. However, device control isn't something I'm looking for in this example - it would actually be preferable for the attached device to retain its own control.

I think I see where you're going with this...

What I am talking about is literally equivalent to a line in via USB, which the USB standard apparently supports. For all I know, this may be the method by which the iPod/Zune sends audio data down to the head unit; it would make sense for them to do so. It's this method that I want to use.

I think you're right that it's the method that iPod and Zune use, but I'm not sure. I'm on board with the idea now though.

The issue I can see is that even if it is capable of doing audio over USB, that functionality may not be activated unless an iPod or Zune (specifcally) is connected - so just plugging any old device in may not work. However, I'm going to be near one of Crutchfield's stores in the next couple of days, so I'll bring the phone and a USB cable with me and give it a shot.

And here he reveals his master plan - connecting a phone to a HU. I am not sure what will happen, but I forsee one of 3 things happening after you plug it in:

-the HU can control the phone's storage files just like it would with another type of removable media
-the HU can't control the phone, but that's ok because the phone will stream it to the HU via usb
-it doesn't work at all.

(I think the HU would see the phone the same way it would a USB stick... but I could be wrong)

Maybe I can get one of my friends with a fancy phone and a usb cable to plug it into my HU. Here's the manual for my CDA 117. There's some info in there about what it can and can't read off of starting on page 32 of the pdf (page 30 if you read the # on the page)

How about another option that might be easier? Most phones have a line out jack for headphones or whatever, right? Why not just get a HU that has a 3.5mm line in and run a double male ended headphone cord? My VW comes stock with a line-in spot in the glove box. That's how I played my iPod before I got my Alpine. (sorry to keep dwelling on the iPod, but it's the only thing I have experience with)

Edit: There's another option that I just thought of after a quick search. Streaming the sound from your phone to your HU via bluetoooth. You'd control everything through your phone and it would be wireless, but you wouldn't be able to charge it like that. That would be a slick setup though...

 

[casm]

And here he reveals his master plan - connecting a phone to a HU.

Yep, I was deliberately being vague about that so that we didn't end up fixating on the device rather than the connectivity. Looks like the cat's out of the bag now, though

I am not sure what will happen, but I forsee one of 3 things happening after you plug it in:

-the HU can control the phone's storage files just like it would with another type of removable media

That I would pretty much expect to be the default case based on how the phone behaves when connected to a data-capable USB source.

-the HU can't control the phone, but that's ok because the phone will stream it to the HU via usb

Which is what I'm hoping for, but not holding my breath on it happening.

-it doesn't work at all.

Also on the cards, but I think the first one is most likely.

(I think the HU would see the phone the same way it would a USB stick... but I could be wrong)

That would be my guess.

Maybe I can get one of my friends with a fancy phone and a usb cable to plug it into my HU.

*Shrug* it's gotta be worth a shot, at least.

Here's the manual for my CDA 117. There's some info in there about what it can and can't read off of starting on page 32 of the pdf (page 30 if you read the # on the page)

Cool, thanks. I'll give that a look a bit later on.

How about another option that might be easier? Most phones have a line out jack for headphones or whatever, right? Why not just get a HU that has a 3.5mm line in and run a double ended male headphone cord? My VW comes stock with a line-in spot in the glove box. That's how I played my iPod before I got my Alpine. (sorry to keep dwelling on the iPod, but it's the only thing I have experience with)

It may sound like an odd reason for not wanting to do that, but here it is: cable clutter. Even plugging the phone into the power outlet to charge it bothers me; if there was another cable floating around it'd drive me up the wall. And since I'm going to be putting some form of USB infrastructure in the XJ at some point, it'd be good to aim for working with that.

My backup plan is to use something like this to feed the audio over Bluetooth to the head unit's aux inputs, but would really like to keep to the USB idea if it's workable.

 

[asp]

Yep, I was deliberately being vague about that so that we didn't end up fixating on the device rather than the connectivity. Looks like the cat's out of the bag now, though

I think the device makes a difference - heck, even which phone might make a difference.

That I would pretty much expect to be the default case based on how the phone behaves when connected to a data-capable USB source.

That was my reasoning too.

Which is what I'm hoping for, but not holding my breath on it happening.

Hmm... I wonder if there's a way around it while keeping the USB... I have an idea but I don't know if you'll like it.

*Shrug* it's gotta be worth a shot, at least.

I'll let you know what happens.

It may sound like an odd reason for not wanting to do that, but here it is: cable clutter. Even plugging the phone into the power outlet to charge it bothers me; if there was another cable floating around it'd drive me up the wall. And since I'm going to be putting some form of USB infrastructure in the XJ at some point, it'd be good to aim for working with that.

Naw, I follow. I hate cable clutter too. That's why all of mine is hidden. I rarely charge my POS phone in my car and I can't stand when my GPS cord is dangling all over. I'm considering hard wiring it behind the dash.

Building on the USB infrastructure... It wouldn't be quite as clean as what you want to do, but have the HU on the aux-in option (so it just plays whatever it's sent, as with a 3.5mm line-in), have the USB cable to charge the phone (not connected to the HU), and have the two cords bundled together so it feels like you only have one cord. I think that's going to be the only way that you can stream from the phone and control it from the phone. Personally, I kind of like controlling it my iPod through the HU...

edit: That bluetooth thing is slick, but your phone has bluetooth, and a lot of HU's have it too... so why do you even need it?

 

[casm]

I think the device makes a difference - heck, even which phone might make a difference.

Yep. It's going to come down to hardware and software on both the phone and head unit side being sympatico - after all, it doesn't really matter if one can do it if the other can't.

Hmm... I wonder if there's a way around it while keeping the USB... I have an idea but I don't know if you'll like it.

Let me know. Worst I can do is hate the idea

I'll let you know what happens.

Cool, thanks.

Naw, I follow. I hate cable clutter too. That's why all of mine is hidden. I rarely charge my POS phone in my car and I can't stand when my GPS cord is dangling all over. I'm considering hard wiring it behind the dash.

That is exactly what I did with my GPS and for exactly that reason. Thank God XJ dashes come apart relatively easily.

Building on the USB infrastructure... It wouldn't be quite as clean as what you want to do, but have the HU on the aux-in option (so it just plays whatever it's sent, as with a 3.5mm line-in), have the USB cable to charge the phone (not connected to the HU), and have the two cords bundled together so it feels like you only have one cord. I think that's going to be the only way that you can stream from the phone and control it from the phone.

Yeah, I may have to ultimately consider something like that. Kinda rather not, but I'll cross that bridge when I come to it.

Personally, I kind of like controlling it my iPod through the HU...

For the iPod, I'm fine with that and wouldn't want it any other way. But for what I'm looking at doing with the audio from the phone, it's going to be more of a set-it-and-forget-it arrangement where I'm listening to the same audio stream for hours at a time - and I need the touchscreen to be able to navigate the application supplying the audio anyway. For that specific use, I'm OK with the phone not being fully-integrated with the head unit.

edit: That bluetooth thing is slick, but your phone has bluetooth, and a lot of HU's have it too... so why do you even need it?

Oh, I was looking at that as an add-on to my existing stereo (CDA-9856) if I end up not replacing it. Alpine's KCE-400BT Bluetooth adapter is an overpriced pile of rubbish, so feeding that 3rd-party one to the head unit via the aux inputs could be a reasonable middle ground.

 

[asp]

Yeah, I may have to ultimately consider something like that. Kinda rather not, but I'll cross that bridge when I come to it.

That's about what I expected you to say.

For the iPod, I'm fine with that and wouldn't want it any other way. But for what I'm looking at doing with the audio from the phone, it's going to be more of a set-it-and-forget-it arrangement where I'm listening to the same audio stream for hours at a time - and I need the touchscreen to be able to navigate the application supplying the audio anyway. For that specific use, I'm OK with the phone not being fully-integrated with the head unit.

When you put it that way... I agree and that makes perfect sense. I hadn't considered wanting to use the phone for other things while driving :confused1

Oh, I was looking at that as an add-on to my existing stereo (CDA-9856) if I end up not replacing it. Alpine's KCE-400BT Bluetooth adapter is an overpriced pile of rubbish, so feeding that 3rd-party one to the head unit via the aux inputs could be a reasonable middle ground.

Ah, that would explain it. So that little doohicky would hide behind your dash and automatically connect to your phone when you get in the car? That sounds like a winning idea to me. Certainly a lot cheaper than a whole new HU. That way you could have the one USB cable tucked neatly away to charge your phone too.

 

[XJLI]

so what phone are we talking about here? obviously not an iphone since thats supported plenty.

i'm fine with using the simple aux in cable when i feel the need to listen to pandora on my android dev over my ipod.

 

[casm]

Ah, that would explain it. So that little doohicky would hide behind your dash and automatically connect to your phone when you get in the car?

Pretty much, yep.

That sounds like a winning idea to me. Certainly a lot cheaper than a whole new HU.

True, and I'm really not desperate to change out this head unit; it's six years old, but works fine. The main problem is that its one aux input is currently used by the integrated XM receiver. I can break out another input from it, but that requires both finding the now-discontinued KCA-801B adapter and figuring out how best to wire it to 12V so that it switches inputs properly. At that point, I may as well just start looking at upgrades for the amount of headache going this route is likely to be.

That way you could have the one USB cable tucked neatly away to charge your phone too.

The plan is to mount female USB A sockets at various points, then use short patch cables from the device to the socket. Should work well for both charging and letting everything talk to each other if necessary (assuming I can ever find the correct USB hub).

so what phone are we talking about here? obviously not an iphone since thats supported plenty.

T-Mobile G2/HTC Desire Z. In theory, though, this should be workable for anything capable of USB audio.

i'm fine with using the simple aux in cable when i feel the need to listen to pandora on my android dev over my ipod.

Agreed, but that comes back to cable clutter. If I can stash it out of the way (my iPod cable runs into the centre armrest bin, for example) that's fine, but it's one reason why I wouldn't consider a head unit with only a front aux in or USB connector.

 

[XJLI]

Agreed, but that comes back to cable clutter. If I can stash it out of the way (my iPod cable runs into the centre armrest bin, for example) that's fine, but it's one reason why I wouldn't consider a head unit with only a front aux in or USB connector.

i guess. i have my ipod in my glove box (ipod cable) and the aux in (from the rear of the HU) coming up into my ashtray where my phone usually lives.

 

[old_man]

I have used a lot of audio to usb adapters, but the thing most people don't really realize is that the adapter is actually a sound card and has to be set up and recognized by the computer. I don't ever remember seeing an actual protocol for straight audio over usb. I have seen the protocol that allows the operating system to use the usb adapter as a sound card. That being said, you head unit would have to behave like a mother board and have drivers loaded.