Audio Delay 0-20 millisec DIY?Matching miked and line signal

majshumlan · 28th November 2008, 04:35 PM

Im thinking of making a box to match a miked ampsignal with a line signal.A short delay varible around 0-20 millisec could work as i can compare the signals on my computer.
Do anyone have a idea for a chip and a schematic for this?

Sen these phase-allignment boxes but they are pretty expensive.

wxn · 29th November 2008, 06:01 AM

If all you need is delay, any decent DSP chip with onboard ADC/DAC would do the trick. Even a dedicated ADC/DAC pair + multipurpose microcontroller would probably do. In any case, you might consider an external memory chip to increase the delay (say you have a 44.1kHz/24bit stream stereo, then you'll need 264.6 bytes of free buffer for each millisecond).

But having a DSP chip and knowing how to program it gives you more flexibility, you can even try writing some auto-alignment algorithm, by comparing filtered signals from both inputs. And also many many other things.

There were pseudo digital chips back in the days but good luck finding one now.

In any case, this adds another pair of ADC/DAC if used in the analog part of signal chain, which is difficult and/or expensive to do well in DIY, especially if you have nice equipment. Ideally, such adjustments should be done after the final ADC, possibly in software if computers are involved.

Markus2006 · 3rd December 2008, 09:08 AM

You may take a look FV-1 chip: http://www.spinsemi.com/ . Printed board is available here: http://www.tonepad.com/project.asp?id=68 . You can implement such a delay with this chip. Additionally you get 8 other reverb-based programs.

Mark

majshumlan · 11th December 2008, 08:31 PM

Thanx for the answer guys!!

I will check it out

I seen these analog boxes too but they are quite expensive.
Maby they can be a easy build too?

http://www.littlelabs.com/ibp.html

Markus2006 · 12th December 2008, 07:36 AM

As you may read on the web site this is not a delay but only a Analog Phase Alignment Tool. This has nothing to do with a 20ms signal delay you asked. Toned circuit based on FV-1 is relatively cheap. If this is to expensive, you may take a look at other delay projects available on Tonepad's web site. I think that there are few of them - analog, based on MN3007. I don't think that you may find anything cheaper.

Mark

28th November 2008, 04:35 PM	#1
majshumlan diyAudio Member Join Date: Nov 2008	Audio Delay 0-20 millisec DIY?Matching miked and line signal Im thinking of making a box to match a miked ampsignal with a line signal.A short delay varible around 0-20 millisec could work as i can compare the signals on my computer. Do anyone have a idea for a chip and a schematic for this? Sen these phase-allignment boxes but they are pretty expensive.

29th November 2008, 06:01 AM	#2
wxn diyAudio Member Join Date: Sep 2003 Location: Vilnius	If all you need is delay, any decent DSP chip with onboard ADC/DAC would do the trick. Even a dedicated ADC/DAC pair + multipurpose microcontroller would probably do. In any case, you might consider an external memory chip to increase the delay (say you have a 44.1kHz/24bit stream stereo, then you'll need 264.6 bytes of free buffer for each millisecond). But having a DSP chip and knowing how to program it gives you more flexibility, you can even try writing some auto-alignment algorithm, by comparing filtered signals from both inputs. And also many many other things. There were pseudo digital chips back in the days but good luck finding one now. In any case, this adds another pair of ADC/DAC if used in the analog part of signal chain, which is difficult and/or expensive to do well in DIY, especially if you have nice equipment. Ideally, such adjustments should be done after the final ADC, possibly in software if computers are involved. __________________ Nothing is as simple as it seems

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3rd December 2008, 09:08 AM	#3
Markus2006 diyAudio Member Join Date: Jan 2006 Location: Poland	You may take a look FV-1 chip: http://www.spinsemi.com/ . Printed board is available here: http://www.tonepad.com/project.asp?id=68 . You can implement such a delay with this chip. Additionally you get 8 other reverb-based programs. Mark

11th December 2008, 08:31 PM	#4
majshumlan diyAudio Member Join Date: Nov 2008	Thanx for the answer guys!! I will check it out I seen these analog boxes too but they are quite expensive. Maby they can be a easy build too? http://www.littlelabs.com/ibp.html

12th December 2008, 07:36 AM	#5
Markus2006 diyAudio Member Join Date: Jan 2006 Location: Poland	As you may read on the web site this is not a delay but only a Analog Phase Alignment Tool. This has nothing to do with a 20ms signal delay you asked. Toned circuit based on FV-1 is relatively cheap. If this is to expensive, you may take a look at other delay projects available on Tonepad's web site. I think that there are few of them - analog, based on MN3007. I don't think that you may find anything cheaper. Mark