Audio Range of 78?s

[James]

Regarding the use of the high and low pass filters, what are some rules of thumb regarding the frequency range of 78?s. I have heard that acoustic 78?s have a range of 150 to 6500 Hz. Anything above or below that can be cut off ?relatively? safely. Is this accurate? As for 78?s from the electric era, what range would one be looking at?

James

[Craig Maier]

I would say that on average an acoustical 78 has a frequency response no wider than 120 Hz to 6000 Hz. Brick wall bandpass filtering with those values is usually a safe bet to eliminate out of band noise. The Brick Wall bandpass filter can be found under the Forensics menu. Thereafter, use the CNF to attenuate the remaining in band noise.

As for Electrical 78's they can have a response running from around 40 Hz up to around 12 KHz for records mastered in the 1940's. Earlier electrical 78's were more restricted on their top ends with the limit being around 8.5 KHz. There is an article on this forum pertaining to the topic of the frequency response of records if you want some more information. It can be found at this link:

http://www.diamondcut.com/vforum/sho...uency+response

keywords: frequency response of 78's, frequency range of 78's, frequency response of old records

[James]

Thanks Craig. The previous article helped as well. Somehow in my restorations, I never added that part to the process. If I miss something that big, who knows all the small things I am missing!

James

[Dan McDonald]

Just make sure you run the impulse filters before the low pass ones.

[Craig Maier]

Good point, Dan. Just for edification, the resotration of old 78's should be performed with the steps in ths following order:

1. Remove Impulse Noise

2. Remove Out of Band noise with one of the bandpass filters.

3. Remove In Band Noise with the CNF (Continuous Noise Filter).

4. Enhance the recording in any manner that you see fit with graphic EQ's, VVA's, Dynamics Processor or the Punch and Crunch effect.

5. Edit the fade-in's and fade-outs.