Distortion in narration but only at certain places

Report · May 16, 2018

I had a friend record a narration. The sample I have uploaded reads:

There was certainly no pack horse at Pelion when I went through with Eric.

At certain places here and there, in this instance at the word "Pelion", the recording sounds very harsh. Normally the waveform is smooth, with rounded tops, but the harsh section has inversions at the peaks – instead of going to the summit, the waveform has a tiny valley.

Q1: Does this distortion come from the voice itself, the microphone, or the recorder (a PMD 661 fed from a Rode NT1A)?

Q2: Any suggestions how I can reduce the harshness? I have tried notch filters at various frequencies, and high cut.

Report · May 17, 2018

Well, it's a compressed file you've posted, so there are no guarantees that this is an accurate representation of what you recorded, but I'm reasonably satisfied that this is a vocal effect you've got here, and a pretty minor one at that. The only place I can see anything looking like damage to the peaks is towards the end of the word, and that's at a relatively low level - the higher peaks earlier in the word are all intact. And that damage doesn't look like real damage either; it looks, and sounds, more like a gravelly voice artifact. Certainly doesn't sound like any system overload damage.

One of the problems with making recordings on relatively good equipment (and I will include both the Marantz and the Rode mics in this) is that small deficiencies in what you record become much more obvious, and I think that's what's happened here. Personally I wouldn't touch it; it's fine. Anything you do to it is likely to be obvious, and make the situation worse, not better. If you want to reduce the chances of this being obvious on future recordings, then try recording with the mic slightly off-axis, so that the talent is speaking across it, rather than at it.

Report · May 17, 2018

Thanks for the comments, Steve. The file was lossless m4a, so that shouldn't be the cause of any problems. I haven't come across a gravelly voice before, and I've recorded quite a few narrators.

So it's in the voice, you think; that the raspiness here and there -- the gravelly sound -- is inherent. That those little valleys near the peaks are supposed to be there. I record two or three takes of narration, and I came across one instance where for exactly the same word in the same sentence, only minutes apart, one was gravelly and the other was smooth. That threw me. But, thinking about it, the gravelly sounds seems to occur when the recording is at a higher level, even though the narrator is standing in the same spot. Maybe when he pushes his voice, it 'cracks'.

Very interesting. I had been suspect about my equipment and situation, especially in cases where a narrator has a boomy voice. I thought: room acoustics. For one old fellow I recently recorded, aged 89, I had to remove a bloom in the frequency response at around 400 Hz. I blamed room acoustics, but maybe he has a 400 Hz bloom in his voice, whereas the "Pelion" fellow sometimes has a gravelly sound, but no 400 Hz bloom.

I'm beginning to appreciate that what's on my recordings is actually in the voice, and that we normally don't notice these artifacts in real life. Maybe the problem is: I'm doing the equivalent of pixel-peeping.

Yes, very interesting.

Ques: why might speaking across a microphone, instead of at it, reduce the gravelly sound?

Report · May 17, 2018

https://forums.adobe.com/people/Guy+Burns wrote
Ques: why might speaking across a microphone, instead of at it, reduce the gravelly sound?

Primarily, this acts as a natural high frequency filter. The sound emanating from the human mouth is, to a degree, directional, with the higher frequencies being more so. The greater the angle between the mic and a direct line out of somebody's mouth, the less HF (and also to a degree, blast 'noise') you get. To get the 'gravelly' effect, you have to add distortion harmonics to the voice, and they are inevitably at a higher frequency than the fundamental voice tone, so if they are there, they are more directional. If you get the mic just a few degrees away from straight ahead, it can sometimes make quite a difference. The extent of this can vary considerably, but it's not the only thing you can do to help...

You can probably reduce the incidence of this by getting the talent to drink small quantities of clear fluid (aka water!) at regular intervals during recording. A moister mouth often improves all sorts of things about the delivery, including raspiness.