Groovy Daniel
Member
Or I could use a soundcard that can output above 48k analog. Any suggestions?
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1/2 speed remastering CD-4 records
- Thread starter Groovy Daniel
- Start date
Help Support QuadraphonicQuad:
I'm such an idiot.
Doing 96K s/r instead of 48 may seems overkill (and in a strict audio sense, it is!) but you have a serious advantage on another level: cleaning the digitized file.
Since ticks and tocks are mechanical transient, a higher sample rate ease out the work of the cleaning software.
So, in short,
- digitize the half-speed played cd4 record at 96/24
- when done, double the s/r header so it is seen as a 192/24
- do a click/pop repair work.
Then proceed as you wish.
Since ticks and tocks are mechanical transient, a higher sample rate ease out the work of the cleaning software.
So, in short,
- digitize the half-speed played cd4 record at 96/24
- when done, double the s/r header so it is seen as a 192/24
- do a click/pop repair work.
Then proceed as you wish.
Jim the Oldbie
My right elbow hurts.
Jim the Oldbie
My right elbow hurts.
I haven't looked at Adobe Audition, but I have its father, Cool Edit Pro. You should be able to configure Audition to record on some tracks while playing back on others, but there might be a limitation on simultaneous record tracks, I dunno. Time to read the directions...
On the hardware side, your 610 does have the 2 "instrument" inputs on the front and 2 line ins on the back, so you're good to go with 4 analog inputs. -- Jim
I read that declicking a CD-4 LP will harm the carrier signal in the recording. I guess if could right where the ticks have been removed. Most declick the 4 individual channels after decoding. But not me, I got to town declicking my drops to 24/96, running in reverse and then in forward getting everything gone I can get. CD-4 LPs were a major benefactor of the ClickRepair software. It turned some of my LPs from VG/VG+ sounding to Near Mint sounding drops. I love it.
Jim the Oldbie
My right elbow hurts.
Only if they're not designed properly. My Outlaw Audio amps have a rated power bandwidth of 5Hz-125kHz +0/-3 dB, and I'm sure there's plenty of NFB going on in there; they are a pretty conventional design.
-- Jim
Groovy Daniel
Member
Just thinking-- even at half speed I'll need a shibata-type stylus or equivalent to track the carrier signal. Should I be concerned about doing damage to the cartridge?
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I can think of a couple of reason for a clickrepair backward... can you enlighten me a bit about it?
You mean why use both directions, and my methods in general? Ok. As we know using lower level strength is best especially if there are drums or percussion parts that could be mistaken for clicks. After a lot of tests I came to the conclusion that setting 15 is about perfect, nice and low but works better than 14 did on some tracks where 13 really missed some obviously ticks. 15 in reverse gets 98% for me but misses some, but very few. Then run the batch of songs at 15 in forward and notice how many small ticks are found that the first run in reverse did not. So each direction can find ones that the other did not. 15 setting is low enough, in "simple" setting is my ideal.
Besides percussion/drums, I find that horns as also probmatic for ClickRepair, it can sense that those small harmonics of several horns playing are tiny ticks and try to process them. I did Chicago Live in Japan 1974, Japanese CBS pressing and had this happen. I decided to remove ticks by hand and not run the software across the songs.
When you see a ton of blocks in red during the process, and you know that the LP is in nice shape, that means you are getting false positives, and should abort imo.
Anyway, setting 15 first in reverse at simple, and then another pass in non-reverse will get the tracks sqeaky clean of ticks and clicks like once in reverse cannot do. It did take me a couple years to figure this all out. I did my Paranoid and Billion Dollar Babies CD-4s to 24/96 and got them super clean. They didn't have bad groove wear, but they both had ticks and loud pops that I'd never imagine I could get rid of without harming the SQ. This has been my first year of 24/96 from quad LPs. I did 40 or 50 in 16/44 (with CR in reverse only), and am now redoing everything in 24/96 and using click repair in two directions.
Plus I've got an internet friend (don't you just love these) loaning me some prized titles I never got around to purchasing on the used market. Grass Roots 16, and The Hoople are two I had on my list and never found clean enough, or cheap enough, but my friend had.
Anyway, two passes just finds things that reverse only just simply misses. Setting 15 I think is ideal as well.
Last edited:
Doug G.
2K Club - QQ Super Nova
Actually, no. At half speed, the carrier engravings are in or close to the audible range with the upper frequency at 22.5kHz. Any good stereo cartridge should be able to handle that.
The carrier signals are not recorded on any separate part of the groove or anything and they are not magical or anything. They are just more signals engraved into the groove walls and can be manipulated by the speed of rotation, just like any other frequency in an LP.
Doug
Groovy Daniel
Member
What digital interface do you use? It sounds like you're doing exactly what I want to do.
Groovy Daniel
Member
Oh okay. Thanks Doug. I just have that iconic WEA innersleeve that explains the CD-4 process, by Ivan Berger, engrained in my brain. I guess for marketing purposes the carrier signal is described as being cut deeper in the groove than the normal signal, and only accessible via the Shibata tip, and conversely (and this probably explains the marketing rationale) the carrier signal is protected from normal stylus wear because a non-Shibata stylus won't traverse the carrier part of the groove. Guess we all know how that worked out
I read too many horror stories about windows defaulting to 24/48, or M-Audio not getting along with drivers, and Audacity not recording to full potential, and the work-a-rounds gave me a headache rather than excitement. I wanted total control, 2-chan, and 6-chan recording and 6-chan output, and of course 24/96 and 24/192 samples rates.
I decided that the Tascam digital recorder model DR 680 fit the bill. http://tascam.com/product/dr-680/ (newer model is said to improve some things). With a recorder I got nicer simpler interface, choice of tracks and sample rates, and easy transfer of files to computer via USB drag and drop. And then I work on them just like any other method. But the recorder seems less full of issues. And the pre-amps are highly rated, noise floor is very low. I love it. The noise floor is lower than my soundcard method I used for 16/44 drops which sounded fine. This was a step up and about $450.00 I think I paid for a new machine. And you don't need it to get along with other software, it records, and then when you plug in the USB, it comes up as a storage device.
I just like recording on a recorder rather than using soundcards. I could go and record a concert or performance with this unit is I wanted.
So the carrier signal could be recorded from another LP (in between songs, silent area), like a minty Sergio Mendez CD-4, and then this recording mixed into another recording of a Joni Mitchell CD-4 LP giving it back it's lost carrier signal in full strong unbroken stream? Or is this idea pure sc-fi fantasy?
Groovy Daniel
Member
Quickstart, you and I are alike. I remaster vintage quad 8's and reels (and now want to work with CD-4). Originally I used an old school EMU Darwin standalone digital 8-track recorder for the initial capture, but it was dependent on cruddy SCSI jaz drives for backup, which I would use to transfer the files to my DAW. So I went the other route, and now have both m-audio and Tascam US 1800 interfaces. They can be quite cagey. Before I do an initial sound capture, I reboot my entire system, and disconnect the internet and any peripherals other than the interface. Otherwise, I might end up with a dropout or gap in the recording. I hadn't considered going back to a standalone device, but you've inspired me. With a good standalone, there's no question that you get what goes in.
Doug G.
2K Club - QQ Super Nova
Yes, that's always been one of the main misconceptions with CD-4 - that the ultra sonic engravings are, somehow, deeper in the groove than the audible frequency engravings. If you look at a photograph of a CD-4 groove, however, you will see that all frequencies cover the entire depth of the groove. The Shibata or other line contact types are used because a very small minor (horizontal) radius is desired to be able to trace the ultra sonic frequencies while the major (vertical) radius is increased to cover more of the groove walls to reduce pressure and, therefore, wear. The increased radius also more assures that the ultra sonic frequencies will be recovered.
The Shibata and other similar types actually ride at the same level in the groove as a typical elliptical but the tip will extend farther into the groove because of the geometry. The tip is not contacting the groove walls all the way to the bottom, however. I think this last feature is the genesis of the misunderstanding about which frequencies are where in the groove and thinking the ultra sonic or difference signals are below the regular audible signals.
Doug
The Shibata and other similar types actually ride at the same level in the groove as a typical elliptical but the tip will extend farther into the groove because of the geometry. The tip is not contacting the groove walls all the way to the bottom, however. I think this last feature is the genesis of the misunderstanding about which frequencies are where in the groove and thinking the ultra sonic or difference signals are below the regular audible signals.
Doug
Yes, but the main difference in what I am doing and what you are doing is (I think) you want to record the 4 decoded channels at say 24/96 from the demodulator / line-out correct (the Tascam works just fine for this), yet I am simply backing up quad LPs both SQ and CD-4s in stereo 2-chan and not decoding them. The SQ LP could be played back through a decoder, yet it is not my intention to at the moment.
But anyway, I can't stand messing around with computers and peripherals and them taking up my time. Last century was different, now I'd rather get on with the recording than studying manuals and their installation error codes, etc. A recorder can do more tasks, professional gigs even.
Doug G.
2K Club - QQ Super Nova
What your last sentence said,
It wouldn't work because the carrier has to be modulated by the difference information which wouldn't be there if you tried to mix a straight carrier back into the mix.
Doug
Hence the "Default Brass" setting. It can also have trouble with percussion (and has a setting for that as well). I once tried to clean up a 45 of Billy Joe & the Checkmates' "Percolator" using "Default Mono"...ClickRepair completely obliterated the initial xylophone hits. The results, while certainly interesting, were definitely not what anyone intended!
The software and the process are fascinating and frustrating. Sometimes it turns vinyl into CDs, sometimes it completely destroys everything. Your suggestion of using a low level and running in both directions definitely interests me!
