Live 6 & Tascam Us-144, latency Options

[fluxia]

I wonder if anyone can help me with this one.
I have recently both a mac book pro and live 6 software. I use TASCAM US-144 as audio interface(USB).
i set it all up and works fine with buffer size at 2048 (I/O) but if I try to decrease the buffer size in order to decrease the latency live does not work properly anyymore (the sound crackles); when I brought the buffer to theminimum live froze and I had to force it to quit.

Obviously cannot work with an overall latency of 304 ms!!!
I have never had a Mac before and I cannot figure out what the problem is.

[fluxia]

Remember the issue I raised a few weeks ago about the latency problem with a Tascam audio interface and Ableton Live?
well
I have contacted Ableton and Tascam about it and here are their replies:

*************
Ableton
*************

Hello Andrea,

first of all sorry for the late reply.

> if I try to
> decrease the buffer size in order to decrease the latency live6 does not
> work properly anymore (it makes an orrible crackling sound)

I'm afraid this is caused by the Tascam interface. If the audio signal
begins to crackle at low buffer sizes, the interface is just not capable
to handle such small buffer sizes. You may check if an updated driver
can provide lower buffer settings than 2048 samples.

> Audio interface: TASCAM US-144 (USB) (this audio interface is supposed
> to work with zero latency)

No audio interface can have zero latency. I guess they are referring to
a direct monitoring scenario, where you bypass the A/D converters of the
interface. In any case the signal has to be transformed from analogue
into digital signals when working with audio software. This conversion
takes time and this is what the audio buffer is responsible for.
The lower the buffer settings, the higher the CPU stress. If you set the
buffer to the smallest possible setting and your interface can't handle
it, the computer will try to swap the data conversion to the CPU, which
can cause the computer to freeze.

It is however still a bit strange that the Tascam interface won't work
at decent buffer sizes. Most interfaces are able to get down to 256
samples without problems. Maybe the problem is caused by a faulty USB
connection or an outdated driver. Please try to call the Tascam tech
support. They may be more helpful with this issue.

Best regards,
*************
Tascam replied me in italian and said that they are surprised about these latency values.
They advised me to check whether the usb port was 2.0 (plug the audio interface directly to a usb port (not to a hub) and advised me to use a faster hard drive (possibly firewire). They said that the card should work fine with a setting of 512, if not 256 samples.

I had previously tried to use an external HD but it was an old HD and probably not fast enough. So I bought Hard Disk LaCie (d2 Quadra 500GB Quad Interface External Hard Drive) with the following caracteristics:
- 1 x eSATA Port
- 2 x FireWire 800 (9-Pin) Ports
- 1 x FireWire 400 (6-Pin) Port (iLink 4-Pin & DV Compatible)
- 1 x USB 2.0/1.1 Port
- Capacity 500GB
- 7200 RPM
- 16MB Cache Buffer

I also updated the OS ( my driver and firmware for the Tascam are up to date).
Obviosly I setup LIVE library to the external drive and run my projects from there.
I used the firewire 80o connection.

Well I had no improvement!!

Live still does not work properly (no sound or crackles if I decrese the buffer size ( but still works ok with a buffer size of 2048 samples).

I am now waiting for Tascam's tecnical support to come back to me.

The only thing I can think of is that either the audio interface or the USB connnection may be defected.

I will keep you updated and I would appreciate any suggestion if you have, although I start assuming that is is a hardware problem....

Thank you

Andrea