Corrrect processing order for 78s recorded at 45

[bobv]

I recorded a set of 78s at 45 rpm, using a sample rate of 25358 (44100 * 45 / 78.26). I can play it at the correct speed by changing the track rate to 44100, but I'm not sure in what order I need to do things to correct the equalization. The recordings were made with a BIC 960 (with a Shure M78S cartridge) through the phono input of a Denon DRA-35V receiver. I believe I should:
1) Reverse the RIAA equalization
2) Correct the speed via the track rate
3) Apply the correct equalization (whatever that may be)
4) Cleanup clicks, etc.
Other posts I looked at said to adjust the speed, then the equalization. Since the pre-amp applied the RIAA equalization to the slowed down signal, wouldn't this apply the Inverse RIAA equalization to the wrong frequencies? Several posts said to use the Change Speed effect, presumably on a recording done at the normal sample rate (44100), but will that properly handle the equalization? I don't want to to re-record these unless necessary because there are cracks in some of the glass-base records which are probably the only copy of a WWII era radio broadcast.
Thanks in advance for any advice.

[kozikowski]

You know most of the elves on the forum would rather open a vein with a rusty knife than do what you're doing, right? 78 records take a special needle to avoid noise and distortion, phono cartridges act funny at other than the speeds they were designed to use, and you're right, very special consideration must be given to removing the RIAA curve equalization, especially given that some 78's didn't use RIAA.

If you have glass masters, I should make a great deal of effort to play them back correctly instead of trying to adapt the wrong speed and needle and make up for it later. You can achieve remarkable fidelity with proper playback.

Good luck.

Koz

[billw58]

Your technique is correct. As Koz points out, I hope you're using a 78 rpm stylus (needle). If not, stop what you're doing a get one before you continue.

Playing 78s at 45 is something that a lot of people do, since finding a quality 78 rpm turntable is difficult, to say the least. Since you are playing the disk slower than normal, tracking should not be an issue. The top frequency on a 78 will be around 8 kHz, and playing it slower will lower that to about 4.6 kHz.

You should reverse the RIAA equalization before changing speed - now the transfer is "flat". Then change the speed. Then apply the "proper" 78 rpm equalization (whatever that may be - who knows if they are radio transcriptions!).

See this topic for more details on installing a reverse-RIAA curve into Audacity 1.3.x http://forum.audacityteam.org/viewtopic ... 28&t=14547

Brian Davies suggests a different method for capturing 78s at 45, and has a free "Equalization" program that that simultaneously applies the proper reverse-RIAA curve (corrected for the different playback speed) and a chosen 78 rpm EQ curve. http://www.clickrepair.net/

-- Bill

[bobv]

Koz and Bill - Thanks for the info. I am using a Shure M78S cartridge with a 3 mil stylus. I initially tried to mount it on a garage sale 78 turntable, but one screw wouldn't hold and I couldn't balance the tonearm. I was afraid of damaging the records so I switched to my trusty BIC.

I have already installed the reverse-RIAA curve. I will probably not use the combination process in "Equalizer". If I use discrete steps, I can save intermediate results until I figure out the final equalization. Surprisingly, to my untrained ear, it sounds better before I re-apply any equalization. I'll have to get another opinion on that.

If a 78's top frequency is about 8 kHz, would it make sense to filter out higher frequencies to reduce noise? The content is fairly noisy. Audacity's click removal helps a lot, but misses many more. I read that ClickRepair can do a better job. Anyone have personal experience with it or DeNoise?

Bob

[billw58]

Anyone have personal experience with ClickRepair or DeNoise?
Bob

I use both all the time, but for LPs. Each has a 21-day free trial period so you can determine if they will do the job for you. These are sophisticated tools with a bit of a learning curve, but the documentation is excellent.

Surprisingly, to my untrained ear, it sounds better before I re-apply any equalization.

Since these are radio transcriptions, who knows what the proper EQ may be?

-- Bill

[L_Libza]

I have a bit of personal experience using Audacity for digitizing 78 rpm records. I have a 45 year-old turntable that has the 78 speed but no speed adjustment. It actually runs at about 79 rpm so I use Audacity to adjust it to the correct speed. I have a Shure M78S cartridge with the N78S stylus. I use ClickRepair and am very satisfied with it's performance. After my 30 day free trial expired, I purchased the software since I couldn't find anything else that worked as well. Next I apply a reverse RIAA equalization. I use Audacity for the denoise step, but first I think it's important to filter out frequencies at the high end end using the low-pass filter. My rule-of -thumb depends on the age of the recording. For recordings from the 1940s or later I set the cutoff frequence at 9K Hz or 10K Hz; for electrical recordings (1926 to 1939) about 8K Hz, and acoustic recordings (before 1926) about 7 K Hz. Next I use the high pass filter to filter out frequencies below 20 Hz. It's amazing that the waveform can display these sub-sonic frequencies, usually deficiencies in the cutting lathe during the original recording session. I do use the denoise function, but sparingly, since I don't want to remove actual music content. Finally I apply some equallization using the bass boost function. There were no standard equalizations used in those days, however some labels had certain characteristics, but in the end you just have to trust your own ears.

[bobv]

It looks like I'm ready to start experimenting and see how it goes. I really appreciate all the helpful advice.

[waxcylinder]

I use ClickRepair extensively - weel worth the $40 IMHO -see this thread: http://forum.audacityteam.org/viewtopic.php?f=28&t=1994

I experimented with Brian's NoiseRemoval tool for an older LP that I had of even older blues recordings - they were obviously trnascriptions from various 78s and the LP was engineeered before the advent of digital processing. I found NoiseRemoval a little harder to set up than ClickRepair - and I needed different settings for each track - but it did work well.

BTW thanks to everyone for the contributions to this thread. I shall shortly be adding a section in the Manual Tutorial on Transferring Tapes, LPs etc on recording and processing 78's so the input has been most useful. Any further contributions gratefully received.

WC

[waxcylinder]

I have an answer to this problem. I have used Windows Movie Maker for quite a while making slide shows to vintage jazz from my 78 rpm collection (for YouTube upload). In my case the original music is monophonic, but for some reason WMM cannot handle a mono audio track without the distortion. This is a known problem and it has been discussed on other forums, but Microsoft no longer supports this software. The solution is to convert the audio to stereo. Create a second audio track and copy and paste the audio into the second track, then convert it to stereo. Of course it's not a true stereo track but WMM will then produce a clean audio track without the distortion. This is true for either .MP3 or .WAV format.

Pasted here from a different thread - just to keep it co-located with the other 78 info (effectively, me writing it down ... ) - WC

[pdxrunner]

I'll throw out a couple notes on my (limited) experience recording 78's. The 78's that I have are from my father-in-law. The only one I've run all the way through the process at this point is an album of Artur Rubenstein playing Tchaikovsky's Piano Concerto No. 1. (I think there are 4 disks in the album.)

My equipment is a Stanton T.90USB turntable. I use the line level output from the turntable (built-in preamp) to an E-MU 0202 usb soundcard to my Thinkpad W500 running Win7 64bit. The Stanton turntables are IMHO a good deal. Very sturdy direct-drive machines - basically a DJ turntable. The Stanton T* models all (to my knowledge) have full length S tonearms (what you want). The ST* models have short straight tonearms intended for DJ scratching - you don't want these for what we're talking about here. I got a replacement 78 stylus for the Stanton v500 cartridge. The best thing about the Stanton's is that they have a 78 speed setting and a wide speed adjustment range. If you know exactly what speed your records should spin at you can print out a strobe disk with exactly the right spacing of bars. (I saw web site that will generate a custom pdf from any speed you input. I do not remember the site, but you could probably google it.)

I played around with Brian Davies' Equalizer, but was not satisfied with the results. (I'm not sure I used it correctly.) For now my final conversion for portable listening left the RIAA equalization intact, even though it's probably not correct. I did use Audacity's equaliser to boost the bass slighty, and I made a final pass through Chris' Compressor because the dynamics of the original recording were hard to listen to on my iPods.