Hi Guys, just found this board and had a search around and it seems a few people have US-122 and US-122L units so perhaps someone can help me with this problem (or at least replicate it!)

Firstly my hardware... I'm using Logic Express 7.2.3 on OS X 10.4.8 on a 2.0GHz Intel coreduo iMac with 2GB RAM. I've got a Tascam US-122L plugged into its own port on the back of the iMac.

I've been using it perfectly happily with Garageband for a few months but finally moved over to Logic Express and have been trying to reduce the latency by reducing the I/O Buffer Size and have run into biiiig problems!

With the size set at 512 (default) everything works but with a large latency
With the size set at 256 everything still works, better latency but still not good enough
With the size set at 128 everything falls apart! LE's cursor plays and pauses and plays and pauses etc... and no sound comes out (well, sometimes a bit of noise but mostly no sound).

It's not CPU loading as it happens even with 1 track, my CPU is sitting around 20% anyways so that's not the issue.

I took a look at the system.log log file (from the Console application under Applications/Utilities) and when I'm using 128 and LE is running, the following message appears every second in the console:

Jan 26 18:51:31 xxxxxx-xxxxxx-computer kernel[0]: USBF: 171139.681 AppleUSBEHCI[0x3a2d000]::UIMCreateBulkEndpoint: USB 2.0 Spec (5.8.3) converting MPS from 9 to 512

It looks to me that there's a (serious) driver issue with this unit. I've downloaded the latest firmware and drivers from Tascam - 1.02. I've unplugged every other USB device. Nothing seems to work.

What I want to know is can anybody either replicate this message and echo that it's unusable with anything less than 256 for a buffer size... OR has anyone got it working in LE without buffer problems? It could of course be something to do with my install but I can't for the life of me think what.

I've e-mailed Tascam but have read their support isn't exactly wonderful so I don't expect a reply any time soon. It's just annoying as it means I can't record a track while listening to the mix including the track being recorded as the latency is distracting. I was hoping to spend more money on instruments but I'm wondering if I should be scraping the US-122L and getting something that works with lower buffer sizes?

Please, please answer, I've posted on both apple boards and bigbluelounge and anyone would think, from the silence I've received that noone uses this combination??

For some reason or another, US-122 and US-122L don't play well with macs. There doesnt seem to be a reason, but where I shop audio, they keep getting them returned by mac users.

That's all I got, sorry I couldn't be more specific, but I'd recommend another interface. Nothing is as inexpensive and portable as the US-models. There's the fire410 - run you 400$, but has 6/6 in/out - midi, preamped universal plugin. runs on fw400.

-Dario

Hi Dario, thanks very much for a reply - I've posted on 3 recording related forums over the past 3 weeks and this is the first response I've got...

I read around quite a bit before buying the US-122L and couldn't find anything negative about it from Mac users, if I had, I wouldn't have purchased one - I'm not disputing what you say but I would be interested in reading other users problems to see if there's anything else gonna go wrong!

It's all very frustrating as I just wanted a cheap, but decent quality, step up into home recording. I live in the UK but purchased this unit in New Hampshire when I was over on business about 3 months ago so taking it back is going to prove a little bit tricky, could be a few weeks before I return to the same area.

Sooooo... I thought about the problem some more and finally it struck me that the error message mentions USB 2. Seemed logical to me to try it out on a USB 1 port (i.e. the Keyboard USB ports on the iMac) and guess what... it works! Wellllllll ALMOST works. I can get the buffer size down to 128 OK but I do get the odd glitch here and there when LE complains it can't keep up with the midi tracks. I have a theory that this is down to conflicts between keyboard/mouse and audio interface data so am trying to locate a USB-1.1 hub that I can plug into the USB-2 ports at the rear of the iMac (to downgrade the port to USB-1.1 protocol) and fingers crossed this may solve the problem.

I'm fairly disgusted by Tascams technical support - 2 e-mails and not so much as an acknowledgment. I'll certainly not be buying any more of their products any time soon. Perhaps if I spot something decent I'll eBay the US-122L as it's immaculate and boxed (any offers? ).