Create Digital Music points out that the left-side USB ports on the newer MacBooks are bad–music gear companies like M-Audio recommend that people use their stuff only with the right-side ports.
Something’s going on with the one or two left-hand USB ports on all MacBook Pros. I’ve heard some issues with hard disks, and now some problems with audio. (Controllers are evidently just fine.) The solution: use the right-hand USB port for audio instead.
The consensus is that it’s because most USB ports now supply extra electron juice above and beyond what’s expected, and that rather a lot of modern gear expects to get power that might not be on offer.
But why would Apple mix and match in a single machine? Perhaps there are problems associated with over-current, and they want to make sure every machine has to-spec USB ports that everything will work with–just so long as it doesn’t want more than 500mA.
Mac USB audio woes … [Create Digital Music]
The MacBook. All USB Ports Are Not Equal [Wired: Gadget Lab]
There is a tremendous difference from manufacturer to manufacturer when it comes to laptop USB quality. Most laptops tend to be able to power one device fully, and the rest will suffer. Dells are decent, Lenovo is too; Acer is the worst. Toshibas are the only laptop we’ve seen that will give 100% juice to every port.
As laptops have made their way into the classroom, we’ve seen this occur when the laptop is used to drive a smartboard (needs 4.5ish, but really wants 5 volts), a bluetooth adapter, and an Elmo document cam.
Powered hubs to the rescue…
I’ve been utterly unable to power a portable external hard drive from either of my Mac’s USB ports.
The only way I can get enough juice is using a splitter to use both, and that fails when the drive tries to work too hard. It’s a pain.
If so, then they’re in violation of the USB spec, and I have no sympathy.
Actually, I’m not sure that’s exactly right. It’s unclear to me whether the USB ports are actually delivering *less* juice than even the USB spec promises.
The issue with the USB audio devices seems to be inconsistent power performance, not just power-hungry devices. And Apple doesn’t *have* to cram so much stuff onto one bus. I’m assuming that by doing so, they save money and battery life — good for a lot of people, but not for people using audio.
Also, as I had suggested (and comments confirm), this is an issue across laptops in general, not Macs per se, before this becomes a misguided platform war. (Of course, under the hood, a MacBook *is* an Intel PC with a whole lot of off-the-shelf parts.)
Ever burn a 700MB / 80-minute CD-R? That’s out of Redbook spec too, which is 640MB / 74-minutes. But 700MB are defacto because all the optical drive hardware is precise enough to read/burn the tighter 700MB spiral.
Imagine using a CD-ROM drive that doesn’t support 700MB discs!
Why not simply offer up to 1000mA or more, and allow non-spec devices to actually work? (This is mostly for demanding bus-powered devices such as external 2.5″ hard drives and optical drives, but also includes the aforementioned USB Audio equipment.)
p.s. I’ve been complaining about Apple’s “underpowered” USB ports for “forever” (i.e. since the problem started with the Aluminum Powerbooks).
p.p.s. I’m also frustrated by how Apple / OSX actually abides by the rules against “vampire” USB devices. It will only deliver 100mA until a device “registers” as a full-power device to receive 500mA. For example, this means you cannot recharge your BlackBerry via laptop USB until you install the BlackBerry Desktop driver. (But otherwise BlackBerry is just a Mass Storage Device, so if not for this silly charging issue you wouldn’t need a driver.)
I’ve never been able to run two Blue Snowball microphones at the same time on my macbook pro. Even just one tends to be wonky after more than an hour of recording. Sucks.
Well, folks, do consider a fix:
* Use powered a USB hub.
* Carry AC adapters.
* Try swapping ports.
It’s a pain, but any of these could help. There are also ExpressCards for adding additional ports, but I haven’t found those to be entirely predictable, especially with USB. And again, power can be an issue, so I would suggest the above (not necessarily in that order)
“Perhaps there are problems associated with over-current, and they want to make sure every machine has to-spec USB ports that everything will work with”
That is the justification you jump to?? They meant for them not to work? I gotta say, that’s kinda silly.