Audacity Forum

Howdy,

I'm using the Audacity 1.3.11, Jan 1st Nightly Build on a 20" iMac running Snow Leopold. After my wife records an LP or two we've found that the Mac is in a sideways state. Two examples:

1. Skype audio doesn't work: We tried to talk to my Pop, but while we could hear him fine, he could not hear us. Verified that Skype mute wasn't on and check the sound settings; input wasn't the built in microphone (Audacity should switch this back when it exits, right?) I switched back to the internal mic, but no joy. We had to restart the Mac to be able to Skype again.

2. Can't import MOD files from a Canon FS200. Attempts to drag and drop a MOD file onto StreamClip & the desktop failed and the camera/USB connection was very slow. After goofying around the Mac's speaker started to emit 'pops' ever few seconds. On a hunch I restarted the Mac; and all was well.

So it appears that Audacity 1.3.11 leaves the Mac in an add state that requires restarting the Mac!

How/where do I report this (or did I just do it

BTW: I'm using 1.3.11 becuase of the 1.3 beta export multiple bug. Will there be a second beta?

Randy

1.3.11-beta was released on January 18. Give it a try as it may have some improvements since Jan 1.

As for your other probs, sorry, I'm not running 10.6 nor Skype so I'll can't verify them.

-- Bill

Are you using any other USB devices? (for example a USB microphone or turntable?)

The Turntable is a audio-technica AT LP 120 USB (http://www.audio-technica.com/cms/turnt ... index.html).

In addition the mac has two USB drives; a 500GB which is used to store my wifes rather large iTunes library and a 1TB for Time-Machine backups.

We've had recording problems in the past; Audacity would either lock up, or the recording & playback would suddenly turn tinny. We believe that it was due to a cheap USB hub in the turntable path (the Mac has only three USB connectors in the back.) We removed the router and no problems for the past 3-5 LPs. As a matter of fact, we ran a test last night where I kicked off a backup in the middle of a recording with no prolblems. I guess we should but the USB rounter back in the path to be sure.

Anyhow I assume the reason for the question is that its possible that the Mac doens't like the USB turntable?

Randy

USB turntables don't like routers, but they like USB hubs even less. When recording audio (or video), the USB is required to record a constant data stream in real time without interruption. USB is not at that at the best of times, but if there is a chance that the USB stream can get interrupted by another device then it can make a real mess. USB hubs are the worst because they do not manage the data at all but ideally there should be a direct, not shared, USB connection from turntable to computer.

There is a common problem on Windows computers that sounds very much like this, but not being a Mac user myself I don't know exactly how it happens on Macs or what the "correct" way to deal with it is. On Windows, when a USB audio device is connected, the operating system passes the entire sound system over to the USB device (yes, Windows passes the playback system over to USB turntables even though they have no playback capability). At the same time you have Skype, which takes a domineering role with the sound system and is trying to take over full control. So then you have two different things fighting for dominance.

As I say, not being a Mac user I'm not sure of the correct way to deal with this on a Mac, but the quick 'n' easy method should work just as well on a Mac as on Windows, which is to disconnect the USB device and reboot.

Hopefully a Mac user will come along and advise if there's a better way.

BTW, Audacity has very little direct control of anything in the sound system and is very much at the mercy of how the sound system is configured. What Audacity tries to do is to guess what is available and then try and use it. Fortunately this usually works quite well - you plug in the USB turntable, the turntable takes over, and then Audacity says "Ah! a turntable... I'll use that". If the first guess is not right, that's when you have to step in and set it up manually.

On Macs, plugging in a USB input device has no effect on the sound settings. The USB device is recognized (hopefully!) and appears in System Preferences > Sound > Input, but the input device is not changed. Furthermore, the Mac seems to know that the USB input device does not support output and therefore the device does not show up in System Preferences > Sound > Output.

Avoiding USB hubs (I presume that is what you mean by a router) is, as Steve says, essential when recording audio. Griffin used to make a special "audio USB hub" that apparently gave priority to audio devices, but it is no longer available. To free up a USB port on the iMac, plug your keyboard into the hub - that is one device that doesn't need high speed. So of the three USB ports on the iMac, one has the hub, one has the iTunes drive, and the third has the turntable. The hub can safely service a keyboard, printer, scanner, camera, card reader, flash drive, external drive etc.

I've never tried Skype, but everyone says that it is quite aggressive in taking over the sound pathways on the computer. Perhaps Koz could chime in here? Is it possible to turn Skype "off" when using the turntable? A bit of a PITA, I know, but probably easier than constantly re-booting.

-- Bill

Thanks for the detailed replys.

My wife has Skype start up at boot. While we where battling the Belkin USB hub (http://www.amazon.com/gp/product/B000NA ... hs_product), she was stopping Skype before doing any recording. We'll do some experiments with Skype on & off in the future.

Thanks,

Randy

Skype does Not Play Well With Others. Skype got its reputation of nearly always working by viciously ripping sound services away from everything else and only sometimes giving them back when it's done. This is a major problem when producers want to create a podcast and include live Skype performances. Good luck with that.

I'm not shocked you have to restart the machine to get everything back to normal, but most people don't have to do that. I suspect you have a number of complications there and each one contributes to the instability.

Audacity is a really simple sound program and likes running on really simple machines.

And yes, confirming that live performances and USB hubs do not get along. Oddly enough, there is one exception. If you have troubles with your USB microphone, it might be possible to eliminate them completely with a wall-powered USB hub. The microphone gets its clear, well-behaved power from the hub and the wall socket and not the ratty power inside the computer. The trick is you can't use that hub for anything else. If it's a four-way hub, connections 2, 3, and 4 are not used.

Koz

Koz,

Thanks for the info., but I don't have a USB mic; we use the internal Mac mics for Skype and iChat, but our USB hub is wall powered. The idea behind the hub was to make it a little easier to attach more than three devices to my wife's Mac; two USB drives, iPod, camera, etc... but we're back to using the built in USB ports as the hub as been so troublesome.

My wife is now shutting down Skype before recording LPs with Audacity... so far so good.

Randy