Anyone help with persistent hum on voice recordings

[Derek Smith]

I use speech recognition software. While it is generally OK, there are some errors that persist. I’ve discovered that the built-in sound in my desktop has a persistent background hum. I’ve test the various mics I use on a Sony Dictaphone and there’s no such problem.

If I bought a soundcard, or an external one, is it likely to eliminate/reduce this hum?

I've gone via Google but there seems to be nothing specific to my problem.

[dundarach]

Yes external could do, I used to have terrible hum from internal card, external USB gone completely.

[Derek Smith]

dundarach said:

Yes external could do, I used to have terrible hum from internal card, external USB gone completely.

Thanks for that, and so prompt. I'm off to Amazon.

[Mr Pointy]

I don't know if you do much conference/Teams work but if you do have a look at the Jabra conference speakers, although for dictation a headset might give clearer results if the room is noisy. There are often plenty on ebay for better prices than Amazon:

https://www.ebay.co.uk/sch/i.html?_from=R40&_t...

£40 will get you an unused 410 (USB cable version): if you do want to use it with Teams get the MS version not the UC, but I don't think there is much difference.

[Derek Smith]

Thanks for that. I've got a number of mics as I thought It might be the problem. However, my dictaphone records without a sound, so to speak.

[mmm-five]

Could it just be electronic interference from a relatively low-end motherboard?

[xeny]

I've found front audio sockets on PCs tend to be noisier than the ones at the rear, so you may have a cheap easy fix, depending which you're using at present.

[Derek Smith]

I've got a mid-range Tuff 570 m/b with a Ryzen 9, not overclocked. It was mid-range when I bought it. It's actually dearer now. The world's a weird place. It's only in the last couple of months that I've found the fault when trying to do voiceovers for videos. No problem in that respect as I just record it to my dictaphone, but when I checked the on-board sound, using audio software, I discovered the hum. It's at a consistent. I can filter it out, but only post recording, and it reduces the overall volume. The only significant problem is with voice recognition software.

I checked that no fans were on when recording, even disconnecting the light display just in case, but it seems the noise is built-in. I've got three low/med quality microphones and my original belief that it was a fault with them was negated when I used my dictaphone. Oddly, the cheap, £15 or so, lapel mic is all but indistinguishable from the dearest, nearly £60, on the dictaphone.

I'll see if an external sound card changes anything. It's coming tomorrow. It's a cheap one, but if it makes any difference with the hum, it'll show. I'll update the thread. On previous builds of my computer I've used an old Soundblaster card, but I've used all the slots up on my current m/b, my GPU taking up space with its fans.

I've stuck my jack in all orifices without much change, but my wife reckoned there were slight but noticeable differences between front and rear connections. I've got hearing problems, although apparently they're not as bad as my computer's.

[jet_noise]

If you are post processing does your software allow a filter with variable characteristics - bandwidth/Q, centre frequency, attenuation ?
If so you may be able to tune to minimise amplitude reduction.
And/or you can amplify as another step after filtering.

Buying a USB A2D mixer (think external soundcard) may well be easier in the long run.

If that's all a bit techie then ask further

[Derek Smith]

jet_noise said:

If you are post processing does your software allow a filter with variable characteristics - bandwidth/Q, centre frequency, attenuation ?
If so you may be able to tune to minimise amplitude reduction.
And/or you can amplify as another step after filtering.

Buying a USB A2D mixer (think external soundcard) may well be easier in the long run.

If that's all a bit techie then ask further

I appreciate the help. I've got quite good IT knowledge, at least I know what you are saying.

I've got a cheap external soundcard today via Amazon and the result is a bit of a curate's egg: on the one hand the hum has gone. Utterly. However, the record volume is lower. I've got various recording software: Audacity - the free one, Soundtap, and a Cyberlink one, this last giving lots of things to play with, such as dynamic range control, equalizer, flanger (which I haven't used by will), and other stuff. I could remove the hum to an extent with that, but the effect on the voice made it sound, well, as if it had been worked on. However, that's all after recording. My real need is for voice recognition. I use Dragon. It's impressive. Slick and more accurate than Google and MS speech recognition, but it doesn't like background noise or low volume level.

I suppose the answer is to speak slower, with better enunciation, or spend out on a scarily pricy mixer. The problem from my brief glance at what is on offer is that most seemed aimed at multiple inputs and offering ways of mixing them, when all I want is no hum and loud. Mind you, some look great fun to use. Really tempting.

As I'm overcoming RSI - ironically I'm a touch typist, and and faster than most - which means I can claim the cost for tax. I'm certain HMRC will be a bit picky if I suggest a £400 mixer deck was just the thing for me.

But I'm pleased with the eradication of the hum. Voice-overs on videos will be much better.

Thanks for all the help provided. A part solution at the very least. I'll try all my microphones and see if there's one that is best.

As an aside, I've got something headed Voice Removal in Music in Cyberlink. I've been meaning to have a go with that. Sounds as if it might be enjoyable.

[jet_noise]

I use Audacity - digitisation of vinyl post processing, click removal, trimming, balancing, amplitude matching.
It has a an effect - notch filter which should be settable for hum removal, I assume it's 50Hz mains.
Then amplify to a bit below clipping, the default level does this, I go for 2-3 below. Because headroom