Differences between version 20 and predecessor to the previous major change of SoundProcessingNotes.
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Newer page: | version 20 | Last edited on Thursday, December 25, 2003 4:02:47 pm | by AristotlePagaltzis | Revert |
Older page: | version 17 | Last edited on Monday, December 22, 2003 10:59:44 pm | by DanielLawson | Revert |
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As a Christmas present, I have decided to convert some my of parents vinyls to CD. In doing so, I hope to remove some of the hiss and clicks you get on old vinyls, and also make sure the contents are preserved - they were either vinyl-only recordings (Tararua College choir, 1961) or unavailable in any other medium these days.
I'll add to this wiki as I go, so excuse the journal-like nature. When I've finished I'll tidy it up, or let a WikiGnome do it for me :)
+''Sorry, this is too longwinded and unwieldly a mess for this gnome to clean up, despite following along with great interest. :)'' --AristotlePagaltzis
!! Hardware used:
I have a Celeron-1300, running Windows 98 (wait a bit...), which has an SB Audidy 2 Platinum eX. As far as I know, there aren't decent drivers for the Audigy under linux, hence staying under Windows 98. That said, I'm not using it very much - it has RCA inputs on its external unit, which means I can plug my turntable directly in.
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Having written this attempt to CD, it seems pretty good. I don't have the turntable hooked up to the stereo to compare the quality, but there are no pops, very little crackle. There is some residual noise still, and the gain is still too low, which makes the noise somewhat worse. When I amplified it before processing, it was amplified to the highest gain possible without clipping - however that was based (I think) on the highest amplitude seen, which was any number of the pops that occured there were about 10 - 15 times louder than the rest of the track. I'm not sure if this will improve the effect of the noise reduction algorithms, or if it will screw things up totally, but its probably worth a shot.
Selecting a better noise sample may also help, although I suspect its about as good as I can get. I'll move onto the next vinyl for now, which I know is in worse condition in some ways (at least one scratch bad enough to cause the needle to get stuck), but may have better properties overall. And the other thing to do is to try an external amplifer/equaliser unit, although I only have the stereo the turntable is connected to, which isn't overly great. I'm open to offers :)
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+!! Fourth Attempt. Or something.
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+OK. If you're going to bother doing this, you'll probably want at least the following equipment:
+
+* A good turntable. Turns out mine wasn't so hot. The stylus is probably the most important bit of this, and I suspect mine has been mistreated.
+* A decent set of headphones (for monitor purposes). And probably a decent set of speakers to check the full range
+* A preamp. The output gain from most turntables is low. This is normal. In one of the vinyls I was trying to restore, it was so low the computer wouldn't record anything. A preamp with monitor output, and simple input/output gain controls is probably fine.
+
+You should also make sure your soundcard has a good SNR. The Creative Audigy 2 Platinum Ex has a good one, although it's taken ages for Creative Labs to turn this product into anything more than gamers toy. There's plenty of high-quality professional level cards that will do this very well, and cost less than the Audigy / Extigy (I checked earlier, I cant remember the manufacturer of the cards I was looking at tho, will append later).
+
+It's now Christmas day. I made a few CD copies of what I acheived last night, which sounded at the time like a great improvement. I'm sure it was a great improvement, however its wise to use the correct speed setting when playing back records. I'd been testing the input with a Faith No More LP (45), and forgot to flick the speed setting back down when I started with Music for the Feast of Christmas.
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+I'm thinking of stamping a label on the CDs I wrote calling them "Music for the Feast of Christmas, by the Chipmunks of Ely Cathedral"