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  • Traditional 78rpm Filters (DC7.5)

    Here are my two multi-filters I use on 78s.
    Assumptions:
    1. the recording is made flat

    2. the file must be adequately declicked before using the 1st multi-filter

    Down to business:
    1. run multi-filter 1 using the correct EQ and low-pass rolloff to remove usless content. Adjust the median filter 3 for good records, 4-5 for bad.
    • Make sure the final average volume of the recording peaks around -3db to -6db. Where I get short peaks that prevent me from making the overall volume of the file reasonable I use the dynamics processor or Punch'n'Crunch to compress the peaks.
    2. Denoise the file using the CNF
    • (I generally use standard mode, 4096 FFT, 30% overlap, 80-125 Attack, 180-250 Release, 8-20dB attenuation).
    • I tend to push the attenuation as much as I can whilst avoiding noticeable changes in fidelity and artefact induction.
    • On good records you can go as high as 20-25 no problems, on some bad records, 8dB may cause issues. If that happens, I use a high FFT as above, followed by another run with 1024-512FFT.
    3. Run multi-filter 2.
    • Find a theshold (usually 30-35) that doesnt capture too much hiss in the VVA. I keep the output set to around 50-60. Any higher and it sounds too buzzy in places.
    • Use the spectrograph and/or spectrum analyzer to establish the volume of residual noise and then move the threshold bars in the Punch'n'Crunch filter to be slightly above that.
    • Keep the expansion ratio around 1.3-1.5 and the output attenuation around -6dB or more such that you dont get frequent/significant clipping.
    • I'm generally too lazy to adjust the dynamic noise filters, but if you get too much hiss, increase the attenuation of the 1st 2 in the chain OR it means the deNoising was done badly/the VVA threshold was set too low.
    Good luck!
    Attached Files
    Last edited by Craig Maier; 08-03-2019, 04:38 PM.
    At work I may look like I'm doing nothing, but at the cellular level I'm actually quite busy

  • #2
    A continutation from the above. This multi-filter preset file includes "2b" which uses the VVA in high noise mode. I was using this yesterday and getting excellent results (the new VVA is based on a filter setup Craig had sent me earlier). As with the others, adjust the VVA mix from dry-to-wet for the sound you want.
    Attached Files
    At work I may look like I'm doing nothing, but at the cellular level I'm actually quite busy

    Comment


    • #3
      My way of restoring a 78 rpm record

      HI!

      I have a somewhat other way of restoring 78 rpm records that I would like to share and receive commments to.
      First I would like to say that my philosophy for restoring and enhancing such records has changed drastically during the last years. About 8 myears ago I was very inspired of the work of the late jazz expert and sound engineer Robert Parker who had a radio program series and CD series called "Jazz classics in digital stereo". His aim was to make old jazz records sound suitable for a younger audience with no knowlegde to 78 rpms and their sound limitations. He therefore added on some reverb and stereo effect, trying to make those old recordings sound like new. On the oposite side we have the late sound restoration wizzard and jazz enthusiast John R.T. Davis. His philophosy was to get the most and best out of the record, as originally recorded. Both these persons are among my "heroes" of sound restoration work, sounding very good, but of course very different.
      So now my philosophy has tured over to the latest; to get the best out of the record, as recorded!

      To do this I have a Thorens turnable TD521 with SME3012-R arm and Stanton 500 cartrigde and a series of different custom made styli of different sizes. I mostly use a stylus called Rek-O-Kut D5130E, an eleptical stylus for most purposes, also for Edison Diamond Discs, it's said. Then I use a Rek-O-Kut Re- equalizer that helps me to re-create the correct eq-curves; rolloff and turnover) according to age of recording and country (US or European mostly). So I have an analogue unit called Packburn 323A Audio Noise Supressor. This set up works very fine for normal analoge playback of 78's. BUT for digital restoration work, using DC7 I only use the Packburn when restoring Edisons, because it has a switch for vertical records. For all other digital restorations I keep the Packburn out of the circut. So, I do not record flat, but use the correct eq curves when recording, using my re-eq unit. The re-eq unit transforms the sound from stereo to mono, but I always records the music into the program in stereo, although this means that I operate with two similar right and left programs.

      After recording the finish eq'ed music to the computer I start up whith the digital restoration work:

      1. EZ Impulsive filter; settings, scatch 60 / crackle 60 / narrow cr. 60. For newer 78's from the 50's I use; scratch 40, cr. 30/ narrow cr. 40. The "solo/brass" is turned on.

      1. b) If it is a worn record I add on the Median filter in adition to the EZ Imp. filter. Settings; samples 3 / weight. 0
      For records in ok or better condition I normally skip the median Filter.

      2. Highpass filter: to reduce the rumble I use the settings; 56 / 24db/oct./Butterworth (as seen in the user manual, figure 9, page 42)

      3. Continous noise filter is used for reducing hiss. I have spent hours and hours on learning how to get the best results out of this filter procedure, since this is a stage where plenty of mistakes can be done! I start up with a sample of the noise from the outer groove of the 78 disc. Then I move the treshold line up, about 3-5 clicks. Right now I use these settings: attack 125 / release 250 / attenuation from 5 to 20 depending on how noisy the disc is. FFT:2048. After this I manually moves the blue treshold dots up where neccesary, and sometimes adds in some more. The blue dot number two from right I use to move some extra up, to about -30-40 db.(as seen in the user manual, figure 12, page 46) Normally this gives me a good results with a great surface noise reduction with clean sound and no digital artifacts. I do not try to "kill" the surface noise completely (as many probably do..), rather reduce it to a minimum and keep the music as natural as possible.

      4. Enhancing the sound: Although the result by now should work well I like to add something to the sound to fresh it up a bit and make it more "upright". But as mentioned, now I do not like to add something to the recording that was not recorded originally. I have therefore made a multifilter chain with the following "filters":
      a) Paragraphic eq; I use this to lift the bass range a bit, lifting the 3rd dot from left, about the 100 hz range, up to 12.00 (as seen in the user manual, figure 15, page 51)
      b) Low pass filter; I use this to cut some of the unneccesarry "high notes" in the music taht often occurs "rasping" and "distored" sounds. Settings: frequency 10000 / 24 db/oct. / Butterworth. On some rather old and noisy discs I may reduce the frequency down to 7700 (the pre-set "steep 78 rpm surface noise att.)
      EZ Enhancer; Before i loved the "Virtual valve", but since that often produced a quite different sound (but often powerful and facinating..) from that original recorded I have found that the easy thing also works well, Therefore I have replaced the "Virtual valve apm" from this multifilter chain with this EZ Enhancer and started to experiment with different pre-sets to find the optimal enhanced sound with the original recorded sound in mind. I have by now felt for a pre-set called "warm odd balanced expansion" where the exciter is on the 95 postition. This gives a very natural sound, in my opinion suitable bright and suitable warm, a true improvement of the original sound on the 78 rpm disc; the real sound from the recording studio, free from clicks and crackle and with a minimum of surface noise and no digital artifacts. In other words; the sound that I want! Any comments??? Hope for a lot of feed-backs and ideas for improvements for this letter; that's the reason why it is so detailed!! Happy new sound restoration year from Jan Myren, the young 78 rpm disc collector and sound entusialst from NORWAY

      Comment


      • #4
        Comments

        Jan,

        Most interesting ,detailed method. I just finnished a large restoration on some 78 records. As such, my method is different some from yours.

        1. I found that the narrow crackle filter (33/3) helped a lot with worn records.
        Some times I used a series of the narrow crackle filters in a row.

        2. The continuous noise filter with the artifact surpression on, cuts out some 78 record distortion that was very difficult to remove. For example, the distortion from trumpets in worn 78's is reduced when you use the artifact suppression option. I belive that the correct term in "intermod" distortion...I call it trumpet distortion.

        3. I use two CNF's in a row, with the section from a little below 100 Hz to around 2 KHz lower than normal. It's a method I saw used in this forum before. The main thing is to turn on the "keep residual" to set up the filter so that the distortion is removed, not the music.

        4. I use the EZ Impulse filter with 68/43/10 and then the narrow crackle.

        5. I'm still trying to find a good "EQ" method....

        6. Sometimes the best method is to combine the L and R first and then filter. Other times, keep then separate during click removal and then combine them.

        Regards,
        Marc

        Comment


        • #5
          Breaking the CNF process into to parts

          Hi,

          Interesting discussion here - - - I thought that I would bring up something that other folks have tried and like with regard to the CNF. I am almost positive that Doug does it this way, but he will chime in on his own to correct me if I am not correct on this.

          Anyway, here are the details.

          1. Set a high fft size (8192 or higher).

          2. Take a noise sample

          3. Drag all the high frequency inflection points (blue dots) all the way down. The high frequencies would be defined as anything above around 400 Hz.

          4. Adjust the attenuation for a good amount of low frequency noise reduction and then run the filter. Note that you are only processing the low frequency portion of the audio spectrum with this CNF pass.

          5. After the first process is complete, change the fft size to a smaller value, like 1024 or less.

          6. Take a noise sample.

          7. Drag all the low frequency inflection points all the way down. The low frequencies would be defined as anything below around 400 Hz.

          8. Adjust the attenuation for a reasonable amount of high frequency noise reduction and then run the filter again. Note that you are now only processing the high frequency portion of the spectrum with this CNF pass

          9. Done

          The idea here is to provide high ffts for the bass so that you have a lot of frequency resolution in that portion of the spectrum. Since artifacts are not produced in the bass portion of the spectrum with high fft sizes, it is an interesting option. Then, you use smaller fft sizes for the high frequencies thus reducing the artficating produced in the top portion of the audio spectrum where wider bin sizes are still effective in removing hiss, etc.
          Craig
          "Who put orange juice in my orange juice?" - - - William Claude Dukenfield

          Comment


          • #6
            Re:

            Very interesting matters!

            I must admit I have tried the "artifact suppr. mode" in the CNF without any success, and that really bugs me! I have not tried the methods described here, but followed the descriptions in the user manual. Hope somebody will supply me with some more detailed information, including settings etc. Think here are many possibilities for sound improvements after learning the game...

            ALSO; as showed in my descriptions I do the recordings into the computer from my re-eq where I have setted the turnover and rolloff correctly according to the certain record to restore. I do own a flat pre-amp, but for one or another reason I think it sounds a bit fruitless. The reason may be that I have placed the "phono pre-amp"-filter in the wrong order in the sound restoration process. I used to put it just after the recording, that means before the de-clicking process. Of course I used the settings "from flat preamp hardware to European or US 78 rpms" as described. Maybe I should have put it somewhere else in the restoration process???

            Comments please; those are the things I have struggeled a lot about on DC7, and I am quite sure this will be pretty obvious if only I can receive some help....

            Best regards
            Jan

            Comment


            • #7
              Artifact Suppression mode should work, but you need to realize that much higher settings of Attenuation are required. It is not unusual to set the Attenuation at 10 in non-Artifact Suppression mode whereas values of 50 are not uncommon in Artifact Suppression mode.

              Craig
              "Who put orange juice in my orange juice?" - - - William Claude Dukenfield

              Comment


              • #8
                OK, Thank you! I'll test this out right away!

                Any comments about my problems regardig using flat pre-amp also?
                May it be that I use it in the wrong running order in my restoration process??

                Also like to learn more about the new DC8 (that was rather a quick news from DC7...) and if that offers me much more than DC7 according to 78's stuff....

                Anyway; thanks a lot for really fast and good answers; it is really late in the evening here in Norway right now. Needs some hours of sleep before i can continue with experimenting on DC7.

                Best regards!

                Comment


                • #9
                  Quoting Jan:

                  "Any comments about my problems regardig using flat pre-amp also?
                  May it be that I use it in the wrong running order in my restoration process??"

                  -----------------------------------------------------------

                  Although I have seen Packburn pre-amps/noise suppressors, I do know that they are basically all analog antiques. I think that you will achieve much more accurate results by finding and using a modern flat preamp and let the phono eq curves be applied by the Diamond Cut software (the Virtual Phono Preamplifier or for short the VPA), because the software introduces no errors into the realization of the curves whereras an analog circuit is subject to circuit tolerances, aging, etc.

                  Craig
                  Last edited by Craig Maier; 01-01-2010, 11:04 PM.
                  "Who put orange juice in my orange juice?" - - - William Claude Dukenfield

                  Comment


                  • #10
                    re:

                    Thanks, BUT (maybe I was a bit unclear again...)
                    May be that I have placed the "phono pre-amp"-filter in the wrong order in the sound restoration process. I used to put it just after the recording, that means before the de-clicking process. Maybe I should have put it somewhere else in the restoration process, for instanse after the de-clicking or something??

                    By the way; I do not use the Packburn for re.eq., but the Re-O-Kut re-eq:
                    http://www.esotericsound.com/elect.htm

                    Best regards
                    Jan

                    Comment


                    • #11
                      Hi Jan,

                      We recommend providing the proper phono EQ to the signal before performing de-clicking; that is the way that we designed the system to work although I will not go so far as to say that this is the only way to do it. There may be circumstances wherein it is better to place the de-clicking process ahead of phono EQ. Maybe some other folks can comment on that.

                      Craig

                      ps - - - why are you using an analog EQ box when you have a mathematically perfect digital EQ right at your fingertips by way of the Diamond Cut VPA?
                      Last edited by Craig Maier; 09-28-2010, 02:20 PM.
                      "Who put orange juice in my orange juice?" - - - William Claude Dukenfield

                      Comment


                      • #12
                        Two Part CNF

                        Craig,

                        With regard to the 400 Hz value between the two different CNF filters...I seem to recall a value around 1 KHz ? Or was it 1 KHz and up for one and 1 KHz and down for the other ?

                        However, the method got modified by the time that I implemented it. I wound up taking the region from about 60 up to 2 KHz and just reducing it down, with a gradual rise from 2 KHz up. I did not change the FFT size from 16 K.

                        After thinking about this for awhile, I'm going to re-do some restorations with your approach to the two part CNF. I missed the concept that the Bin size would affect the amount of potential digital artifact....


                        Good thing for batch files !

                        Regards,
                        Marc

                        Comment


                        • #13
                          Hi Marc,

                          I do not know the optimal "crossover" frequency, but 400 Hz plus or minus an octave is a good place to start with your experimentation. Of course, the optimal value will also be effected by the fft sizes that you choose.

                          Craig
                          "Who put orange juice in my orange juice?" - - - William Claude Dukenfield

                          Comment


                          • #14
                            Updated 78RPM Final Multi-Filter

                            This is just an update to my previous settings. Currently I still prefer the sound of running the CNF with a couple of different FFT settings to selectively reduce noise. Following noise reduction I like to implement one of the following multi-filters to enhance the sound (the DC8 version contains the overtone/sub-harmonic synth enhancers):
                            DC8: Final78RPMDC8.zip
                            DC7.5 Final78RPM.zip

                            Some of my favourite songs recently having undergone noise reduction using these filters:
                            Avalon Town (Side1: Parlophone Fox Trot - The Six Nite Lights)
                            I Can't Do Without You (Side2: Parlophone Waltz - Gus Arnehim & his Ambassador hotel, Cocoanut Grove Orchestra)
                            Goodnight Vienna (Columbia Fox Trot - Debroy Somers and his Band)
                            Playmates (Decca Fox Trot, Dick Robertson & His Orch)
                            Last edited by Doug; 03-05-2012, 06:04 AM.
                            At work I may look like I'm doing nothing, but at the cellular level I'm actually quite busy

                            Comment


                            • #15
                              Doug,

                              Thanks for the preset. It sure is a complicated filter.

                              I'll have to check it out.

                              Marc

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