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Post by bossanova on Jul 3, 2024 19:34:00 GMT -6
I made a recording of some music from my vintage NES. I have some other thoughts to share about that project, but my mystery at the moment is why a 40hz, 18db slope HPF from Slick EQ GE is giving me the transient spike as seen in the attached photo. I've had this happen before but normally I haven't been able to definitively isolate the HPF as the cause. The red circled bit is the spike in question, the lower track is normalized to the same peak level as the one below but without the HPF. (The version without has unique extended peaks of it's own, but none on the level of the one in question.)  For those interested in the final results, this is the recording in question (BGM 2 from Silver Surfer): www.mediafire.com/file/7stfdw1lc1x377r/Silver_Surfer_BGM_2_US_RX.flac/file |
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Post by explorer on Jul 4, 2024 6:10:15 GMT -6
The highpass filter is shifting the phase, which can lead to an asymmetrical waveform and a higher peak level.
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Post by copperx on Jul 4, 2024 8:09:26 GMT -6
Here's an explanation by Paul Frindle:
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Post by bossanova on Jul 4, 2024 8:57:22 GMT -6
Here's an explanation by Paul Frindle:
Weird....so what's the solution to the problem short of removing the HPF? Do you just clip the most random, errant peaks that result? |
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Post by trakworxmastering on Jul 4, 2024 9:16:07 GMT -6
Here's an explanation by Paul Frindle:
Weird....so what's the solution to the problem short of removing the HPF? Do you just clip the most random, errant peaks that result? A brickwall limiter after the HPF. |
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Post by drumsound on Jul 4, 2024 9:39:43 GMT -6
Here's an explanation by Paul Frindle:
Weird....so what's the solution to the problem short of removing the HPF? Do you just clip the most random, errant peaks that result? Try shifting the corner frequency of the HPF, and/or the slope. The more severe the slop the more you get that bump just a little higher then frequency where the cut is happening. |
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Post by bgrotto on Jul 4, 2024 9:56:29 GMT -6
Shelf filters tend to have a more gentle impact on phase, and in many (if not most) cases will easily reduce whatever LF gunk might be troubling you.
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Post by andersmv on Jul 4, 2024 12:28:34 GMT -6
Flip the phase on the EQ and see if it goes away.
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Post by EmRR on Jul 4, 2024 20:11:59 GMT -6
Shelf filters tend to have a more gentle impact on phase, and in many (if not most) cases will easily reduce whatever LF gunk might be troubling you. And will let you do things like still use the hpf but set it an octave lower |
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Post by bossanova on Jul 4, 2024 21:19:41 GMT -6
Shelf filters tend to have a more gentle impact on phase, and in many (if not most) cases will easily reduce whatever LF gunk might be troubling you. And will let you do things like still use the hpf but set it an octave lower In this case because of the preservation aspect I'm trying to keep the recording as raw as possible minus the light de-hum and filtering the extremes to eliminate anything non-musical, which means that a low shelf isn't the best fit for this case, although I use them on virtually every other mixing task to shape low end. However, I reached the same conclusion as the above and tried moving the filter down to 20 hz, and it fixed the spikes.  I'll take it. |
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Post by Ward on Jul 5, 2024 11:37:48 GMT -6
all great suggestions above. I've always heard that called 'The Recoil effect' or 'The Bump' (which is used in a BENEFICIAL way in the new chambordaudio BF500 that I am loving) Screw it, let me plug that thing. in all honesty. It is WORTH THE MONEY. It's a fantastic variable HPF and LPF filter, with a bump button and you ALL should have at least one. chambordaudio.com/products/bf-500-filters |
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I'll take it.