78 rpm restoring: DC6 vs. Millenium.

[stefano]

Hi there, I bought few days ago DC6 and I started using it to restore old 78 rpm records. I tested DC6 with a song I restored in the past with Millenium, just to compare program features & capability. When I tested Continuous noise filter (same CNF settings I used in the past, that means Attack=40, Relase=80, Attenuation=10) I was very disappointed to see DC6 added many digital artifacts (flange) to the music. I tried to change settings with no success (Attack, Release & FFT). I was used to hear no artifacts with an attenuation value of 10, expecially when "blu line" was just a little bit above the "red line" (at least noise reduction was not complete !).
In my DC6 test it seems that more the blue line is near the red one, more artifacts are produced ! Does DC6 work differently or there is a problem with it I don't know ?
Thanks !

[Craig Maier]

The DC6 Continuous Noise Filter algorithm is much more sophisticated than that of the Millennium product. Settings that were appropriate for Millennium will not work properly with DC6. You can not compare parametric settings used on Millennium with those which will be successful on DC6. One example of this is the attenuation control. A given setting in Millennium was much less agressive compared to the same setting in DC6 as a general rule. You need to work with some of the presets (as starting points) associated with DC6 coupled with a good noise print and / or start using the Auto CNF feature which takes a variable noise fingerprint on-the-fly.

However, I can say that the fundamental principles are the same between the two. But, that is where it stops. Ultimately, you should be able to obtain superior results with DC6's CNF.

[stefano]

DC6 & Millenium - 78 restoration

Dear Craig,
I did many tests on the same song, but I still have difficulties to avoid digital artifacts with CNF in DC6. I followed your suggestions, and moreover I've red almost all the posts on this topic (I improved the scratch & crakle removing in order to be sure they would not "trick" CNF). The 78 rpm I'm working on is very warped (many clicks & hiss). I had a quite good result in the past by using Millenium (some residual noise but no artifacts)
Do you think the use of MME or WDM drivers can make some difference in CNF ?
Many thanks and best wishes !

Stefano

[Craig Maier]

MME or WDM drivers will not make a difference with the CNF. I am not sure what you are doing. I do know that I get better results with DC6 compared to Millennium when it is adjusted properly. Keep in mind that you must balance all of the following paramaters:

1. Noise Fingerprint

2. Attenuation Control

3. Mode of Operation

4. Attack Time

5. Release Time

6. FFT Size

7. Smoothing (On or Off)

8. Overlap (best set at 40 to 50 %)

9. Overall threshold

As you can see, there are more controls available with DC6 than Millennium. The good news is that you have more flexibility to adjust the system to a wider range of situations. The bad news is that you have more controls that need to be managed. But, once you get the knack of these controls, you will get better results. And, you always have a new mode that you can choose which is called "Auto CNF" which will find its own fingerprint on the fly.

I would suggest that you try increasing the Attack Time as a starter. Longer Attack Time will decrease the degree of artifacting at a slight cost of decreased transient response.

[stefano]

DC6 & 78 rpm restoration

Craig,

many thanks for your answer.

As to the controls you mentioned I start with the "Default" settings, then I take a fingeprint at the beginning of the record. After that I set the controls as follows:
Attenuation Control: 10 (from 5 to 15 max.)
Mode of Operation: CNF (default)
Attack Time: 125-150
Release Time: 250-300
FFT Size: 2048 (default) or 4096
Smoothing: Off (the cut on HF is evident if this set is On)
Overlap: 35-50 %)
Overall threshold: below or overlap the red line for low frequencies (30-1000 Hz), above the red line for high frequencies (> 1000-15000 Hz). Usually I increase the distance between blu and red line while frequencies increase (tipical 78 rpm hiss is nearby 5000-9000 Hz)

I tested also Auto CNF, but default setting seems to live more noise to pass through ("Auto CNF Very Light Setting") or cause many artifacts ("Auto CNF Nominal Setting).

Regards.

Stefano

[Craig Maier]

Ok, so what is the question that remains at this juncture?

[stefano]

Craig,

there is not a specific question. I submitted to you the settings I use, hoping that something was wrong, 'cause I cannot eliminate digital artifacts.

Stefano

[Craig Maier]

I see. It is hard to know what the controls should be set to ouside of the context of the specific musical material at hand. However, the following actions reduce the level of digital CNF artifacts:

1. Increasing the Attack Time

2. Inreasing the Release Time

3. Decreasing the Attenuation Control

4. Turning on the "Smoothing" feature

5. Decreasing the FFT size

6. Decreasing the overall threshold

7. Running the Overlap control greater than 40 percent

8. Adjusting the blue dots towards the upper end of the spectrum manually. You can add blue dots manually if you want with DC6 if you need more to achieve the degree of control required. Moving a give dot upwards increases artifacts and moving them down decreases artifacting.

Lastly, I should point out that you will never find that zero artifacting will occur with high levels of noise reduction. It is always going to be a balance or tradeoff between noise reduction and digital artifacting by the system. It is just the nature of the beast. This tradeoff existed with Millennium and remains in the DC6 version.

[stefano]

Many thanks ! I will follow your suggestions and I'll keep in touch.

Stefano