To hear just the high frequencies I should.....?

[James]

To assist me in knowing the frequencies I should start to roll off with the band pass filter, I am curious as to what tools I should use to listen to just those frequencies. It seems I have a pair of options, neither of which I seem to understand all that well, even after reading the manual. In this case, I will be using a Capitol Records 78 from 1953 as my test subject.

1) Block Wall - To try and hear what is just noise, I set the frequency at 7000, the upper frequency at 20,000 and the length at 318 (I believe the default setting). With this setting , I can just barely make out the singing (record is a vocal quartet). Does this tell me that 7000 is an ok place to start my high frequency band pass?

2) Direct Spectral Editor – With this on, I see the red color really start to thin out at 4100 with a fairly equal decay in the color all the way up to 22,000. From around 10,000 on up, there is very little red. How does this information help me locate my setting for my bandpass filter. Also, I can highlight a section of the sound file while in this setting, with the paintbrush icon, but how do I play/listen to only what is inside that highlighted area?

Thanks for any help with this….

James

[Craig Maier]

Hello,

When working audio restorations and seeking to set the out of band frequency limits, I use the Forensics Brick Wall Filter with the filter length set to its maximum value. To seek to hear the frequency content at the top end of the spectrum, I adjust the filter (with the maximum slope/attenuation/length) until I hear no signal. That is the limit frequency that I take note of. Then, I go back to either the Brick Wall Filter (phase linear) or the more standard IIR low pass filter (analog) set to that value so that I can rid the result of out of band noise.

Craig

[James]

I am using DC8, so I gather I don't have the "Forensics Brick Wall Filter"?

[Craig Maier]

Hi,

DC8 has a "Forensics Brick Wall Filter" which can be accessed under the Foreniscs menu. It is just called "Brick Wall Filter". So, the standard version of the software does have some Forensics Audio capability too.