5 second delay

Two tape decks and a loop?

Good Luck! Rich

No this wouldn't work unfortuantly.

It needs to be workable when there is no one else around, plus its live audio.

Its for testing audion on video conferencing systems. We have a system set up in the office, if we are installing another one we can call our own system. As there is not always someone in the office we then need to make noise. Instead of just shouting and making a nose to echo we want a 5 second delay system.

I hope that made sense!!!

Use a PC with a sound card ?

We use exactly that kind of setup to check VC - we have a Tandberg 880 with audio (audio out to mic in, using a XLR conversion cable, video out to video in)

The beauty of the system is that the coding delay (2x!) creates much of the delay you want. Enough to test anyway!

On a sunny day (1 Dec 2006 06:53:19 -0800) it happened "Niall 84" wrote in :

The Linux program 'sox' has several delay related options, echo etc. Never tried it with 5 seconds though. And you would perhaps need 2 sound cards (like I use).

I agree. You could do this with PIC, RAM, with A/D converter, etc., but why bother? Software would be a lot easier.

1. Get two linux PC's, local and foreign
2. When you want to record something, start recording on local PC.
3. Data will be stored in sound file on local PC.
4. Copy file from local PC to foreign PC.
5. Have foreign PC play the data, then delete the file. play/rm commands.

You can put the delay wherever you like.

A Unix programmer should be able to do this in 1-2 weeks reliably.

-Le Chaud Lapin-

to record a sound, and play it back with a 5 second delay. A single sound card should suffice, and a fairly easy program like this:

open sound card repeat: read sample from sound card store sample in FIFO load old sample from FIFO write old sample to sound card

Use a fixed FIFO with size equal to 5 times the sample rate, to get a 5 second delay. The tricky part is to figure out how to access the sound card (unless one has prior experience), the rest is 20-25 lines of code.

On a sunny day (1 Dec 2006 16:27:41 -0800) it happened "Le Chaud Lapin" wrote in :

A *Linux* programmer would do this:

rec -d /dev/dsp1 -r 44100 -c 2 -s w -t raw /dev/stdout | \\ lame -r -s 44.1 -m s -x - line.mp3

This creates a mp3 file from the audio card 2 line input.

Then start mplayer (for example), or xine, to play back via sound card 1:

mplayer -ao oss:/dev/dsp line.mp3

and adjust in the GUI where to start (seconds, minutes hours later).

or

xine line.mp3

Or use sox. (But I am too lazy to try it now and things are running), but syntax is something like this (from an other project)

rec -d /dev/dsp1 -r 44100 -c 2 -s w -t raw /dev/stdout | \\ sox \\

-r 44100 -w -c 1 -s -t raw /dev/fd/0 \\

-r 44100 -w -c 1 -s -t ossdsp /dev/dsp \\ echo 1 .65 1.5 .5

man sox Not 100% sure sox will hack this. Year ago I tried this last.

The payback via xine and mplayer works 100%, it also works for video, it is called: timeshifting.

I understood at one time sound cards could only do simultaneous read/write if one path was 8 bit and the other path was 16 bit. Questions:

1. Has this improved with later sound cards?
2. Can you recommend a suitable (inexpensive) card that can do this?

Thanks, Mike Monett

Antiviral, Antibacterial Silver Solution:

Mike,

I wasn't aware of this limitation. I've used Skype on several computers, which uses both channels at the same time. With current technology such as PCI, USB, and 24 bit * 8 channel surround sound, it would be silly to carry around the same old limitations.

If this is still a problem, use two sound cards. The cheapest ones are about $10 each.

Thanks Arlet,

I must be doing something wrong. I've looked for 16 and 24 bit sound cards, but the cheapest I can find in local stores is $200 to $400.

Can you give the model numbers of some cards? 24-bit would be nice, but 16- bit would still be very usable.

Thanks,

Mike Monett

Antiviral, Antibacterial Silver Solution:

Mike,

The cheapest one I see here (in Europe) is the 7 Euro Sweex 4.1 PCI Sound card. It's based on the C-MEDIA chipset, and it is advertised as

Thanks very much, Arlet. That's encouraging and gives me a target to search for. Regards,

Mike Monett

Antiviral, Antibacterial Silver Solution:

On 01/12/2006 the venerable Niall 84 etched in runes:

Modulate a laser beam and bounce it off the moon? Ah, silly me that will only work when the sky is clear.

The last time I searched, there wasn't very much available. This time, a brief search shows over a million hits:)

There are now plenty of 16 bit, 48KHz full duplex cards for $10 to $20 in Canada. The 192KHz cards are much more expensive, and go from $88 to over $500.

The 24-bit cards I looked at can play back at 192KHz, but can only record at 96KHz.

This is only twice the rate of the 16-bit cards, but the 24-bit cards are much more expensive. For use as a pc scope, it would probably be better to get some 16-bit ADC's and make a simple interface to the pc.

One thing I noticed is some cards have an optical interface. This might be interesting as a low-noise data interface for lab test equipment.

Thanks, Arlet. I have a much better picture of what's available now.

Regards,

Mike Monett

Antiviral, Antibacterial Silver Solution:

digital delay.

if you can live with lower quality less ram may suffice...

Bye. Jasen

Check out all the features available with Sony's sound forge software.