💾 Archived View for mirrors.apple2.org.za › archive › apple.cabi.net › FAQs.and.INFO › CPUandMore › … captured on 2023-01-29 at 07:42:56.
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Path: ns-mx!hobbes.physics.uiowa.edu!zaphod.mps.ohio-state.edu!mips!spool.mu.edu!agate!dog.ee.lbl.gov!nosc!crash!pnet01!pro-hindugods.cts.com!steve From: steve@pro-hindugods.cts.com (Steve Fenwick) Newsgroups: comp.sys.apple2 Subject: Re: GS digitizing sounds Message-ID: <1992May01.040028.20174@crash.cts.com> Date: 1 May 92 04:00:28 GMT Sender: news@crash.cts.com Organization: Crash TimeSharing, El Cajon, CA Lines: 28 In <1992Apr30.024719.6357@visual.spk.wa.us> tkolstee@visual.spk.wa.us (Tony Kolstee) writes: >I also have a question on the mod that I did. When I hook the wires up to >the SPEAKER port on my amplifier and put up the Oscilliscope (sp?) screen, >the sound wave centers around the bottom. If I blast the volume and then >bring it back down, the wave centers in the middle, and it works okay. >Why is this? And how come if I connect my speakers to the amp at the same >time the wave stays at the bottom no matter what I do? Could this be an >impedence problem? I _had_ that EXACT same problem. It is a grounding problem. The Line and Mic outputs of most equipment has a lower reference voltage for the audio waveform signal. To fix this, you need to run it through any op-amp I.C., and have a potentiometer going to ground from the inverting input to adjust the waveform level. Make sure you have a relatively large value capacitor on the output, because I noticed that with small values, the waveform starts to 'drift' down, I don't know why, though. I used an LM324, but any op-amp should work. Hope this helped! Steve ProLine: steve@pro-hindugods | I know Internet: steve@pro-hindugods.cts.com | that you UUCP: pro-hindugods!steve%ttardis@nosc.mil | know.....