78rpm questions...

[Craig Maier]

Quoting Marc:

"This tool seems to add various harmonics and maybe even "reverb"."

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The EZ Enhancer uses no "reverb", echo or any tapped delay effects. (The Diamond Cut software does have those sorts of things under the effects menu, but the EZ Enhancer is not one of them employing tapped delay lines). It does, however use some complex non-linear systems which may bring out or enhance existing reverb on a recording.

Craig

[Craig Maier]

Quoting DougMac:

"I'd be interested to hear how others use the continuous noise filter."

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My process is similar, with a few exceptions:

1. I often add more inflection points (or touch points) onto the graph at the top end and bottom end of the graph (a right mouse maneuver) to improve my ability to fine tune the system. You can pretty much add as many as you like.

2. I tweek the bottom end often with a lower threshold so as to reduce rumble without effecting the bass.

3. On the high-end, I do what you do.

4. When listening in Preview mode, I adjust the attack control in conjunction with the threshold line to improve the result keeping in mind that large values eliminate more musical signal and small values can introduce more artifacts - - - so I look for the best balance between transient response, noise reduction and artifact production with the attack control.

5. Often, I use the artifact suppression mode which really does a nice job on a lot of distorted material (intermodulcation distortion due to groove wear or poor mastering). It also allows more agressive filtering without introducing artifacts because the algorithm is designed to compensate for the psyacoustical sense of loudness with respect to signal noise attenuation. However, the processing time is quite a bit longer with this mode - - - too much math going on there.

Craig

[Craig Maier]

Quoting Marc:

"The CNF has to be one of, if not the hardest filters to use correctly."

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Yup - - - as good as that filter can be when used correctly is equal to as bad it can be when used incorrectly. It can totally destroy music and some people do just that with it.

[Craig Maier]

CNF Hint

Here is a CNF hint:

To obtain the best tradeoff between transient response, bass response and noise reduction, consider breaking the CNF task into two parts. Doug (Aussie Doug from the land down-under and a good friend of this forum) discovered this technique a few years back and it works nicely.

Step One: Set the FFT for a high value (something like 8192 or more). Take a fingerprint of the noise. Then, take all the inflection points above around 500 Hz to 1 KHz and drag them all the way downwards. Run the filter. That way, the high frequency material is not processed.

Step Two: Set the FFT for a much lower value (something like 1024). Take a fingerprint of the noise. Then, take all the inflection points below 1 KHz and drag them all the way downwards. Run the filter. That way, only the high frequency material is processed, but with nice transient response.

That way you get the best of both worlds in terms of noise reduction and retention of the bass signal and transient response.

[Marc Hildebrant]

Two Stage CNF

Craig,

In your first step, do you mean low frequency is not processed ?

Regards,
Marc

[Craig Maier]

Quoting Marc:

"In your first step, do you mean low frequency is not processed?"

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Yes, that is correct. The concept is to provide a very high frequency resolution for the low frequency end of the audio spectrum and then to provide a a very high transient response for the high end of the spectrum.

[DougMac]

Thanks Craig and Doug!

Thanks for sharing Aussie Doug's method of using CNF, I'm going to give it a whirl.

I just bought some 78s including Bessie Smith's "Nobody Knows You When You're Down and Out". I also have this on a commercially released (Columbia) Bessie Smith Anthology.

I restored my 78. It was in much better condition than the average Bessie Smith 78 I see; few scratches and hardly any groove wear. Once I was finished, I played the commercial disk for comparison. I couldn't believe how bad it sounded! I know Columbia has done some better retorations since the CD I own, but I just can't believe they'd release something as tinny and bad sounding as this CD.

Although with better restorations available things are getting better, most folks still think the bad quality on the Columbia CD as being indicative of 78s. Their jaw drops when I play them a restored version of a good 78.

Doug