it's probably out of your price range, though.
Ian Howard wrote:
Hey all,
We are looking for some portable digital recording devices with the following criteria:
- very small - durable - near $100 ($100-150) - usb compatible - linux + windows friendly - mic-in with a reasonable signal-to-noise ratio - descent quality recordings - battery powered
We intend to distribute about 10 - 20 of these units to radio journalists in Mali, whom will use these devices to collect material for their programs which they can then edit in Audacity and broadcast on the air.
We are looking at devices such as the iRiver 190T
Any one have any experience with such devices, in particular using them with linux?
Ian
On Sun, 2004-12-26 at 12:06 -0500, [EMAIL PROTECTED] wrote:
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Today's Topics:
1. Re: Tascam US428 Continued hangups (Spencer Russell)
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Message: 1 Date: Sun, 26 Dec 2004 02:09:21 -0800 From: Spencer Russell <[EMAIL PROTECTED]> Subject: Re: [linux-audio-dev] Tascam US428 Continued hangups To: linux-audio-dev@music.columbia.edu Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset=us-ascii
On Fri, Dec 24, 2004 at 12:05:07PM -0500, Rui Nuno Capela wrote:
... device. It was probably this very one that was aunting you before. After some attention and furious alsa-bugtracker exchange, Karten Wiese has been able to solve this, even tought he's got no OHCI hardware near him.
I was watching that thread a little, because my symptoms were very similar. Strangely, though, I have a UHCI based card, so I'm not sure why I was seeing similar symtoms.
Then Karsten did it again. He crafted a special jackd alsa/usx2y backend which enabled the so-called raw-usb mode of operation. And it was just yesterday I have proposed the merge into the official alsa backend driver on the jackit-devel list. With this new experimental stuff, one can run jackd in realtime with pretty lowest-latency parameters, without aural artifacts (i.e. crackling). AFAICT this is a greatest breakthrough on the USB audio arena, so I would think twice about getting rid of your US428 ;)
I'm having a bit of trouble with the usx2y backend to jackd. I bastardized the jackd-us2xy rpm to make a nice deb file, but jackd still says "unknown driver 'usx2y'". Even downloading and compiling the source, and running it directly from the directory it ws compiled into. And does it automatically use the rawusb interface? What's the advantage of using the usx2y driver as opposed to the alsa driver?
So my recipe goes like this:
1. Have REALTIME_PREEMPT on the kernel config.
2. Make sure you have loaded the latest snd-usb-usx2y>=0.8.7.1 (as of latest alsa-kernel cvs).
3. Tune the RT priorities (SCHED_FIFO) of the time-audio critical IRQ threads: 90 - timer (IRQ 0) 80 - rtc (IRQ 8) 70 - snd (or whatever your PCI soundcard will hook, usually IRQ 5) 60 - usb (ohci_hcd or uhici_hcd, usually IRQ 10) You should have schedutils installed (chrt) for this exercise.
4. Load the snd-usb-usx2y with the nrpacks parameter set for: a. high-stability: nrpacks=4 b. low-latency: nrpacks=1 Anyway, be advised that you can only run the forementioned "rawusb" mode if you set on this later one (modprobe snd-usb-usx2y nrpacks=1).
Run your jackd command line (or qjackctl;) as usual, but given the above priority tunning, you should try e.g. jackd -R -P60 ...
Thanks a lot for this detailed info! I recompiled the newest snd-usb-usx2y driver, but how do I tune RT priorities? I got the schedutils package, but I'm having trouble finding details on how to use chrt.
Thanks again for the info. -spencer
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