How to monitor night sleep ? (Recording audio at night/during sleep)

May I humbly suggest you re-read the OP's original rant. Notice this section which indicates that he is considering marketing his contrivance: In article , wrote: Offer it for sail as: "Night tracker" or something or "Sleep monitor" or "Sleep tracker" or "Night audio surveillance" or "Sleep overwatcher" or Something creative you can come up with. "Night protector" Perhaps it will sell.

Nope. You couldn't hear much of the crosstalk or print-through buried under the hiss. Various schemes to reduce the hiss (Dolby B) equally reduced the recorded voices of the dead.

I do most of my useful work at night. (Some things are best done under the cover of darkness). I hear plenty of noises. Barking dogs, raccoons emptying trash cans, the neighborhood owl, rats and mice under the house, an irritating rooster, my refrigerator, buzz from some switching power supplies, smartphone notifications, etc. In the morning, these sounds are augmented by falling acorns, and a battle between the squirrels, cats, dogs, blue jays, etc for supremacy on my flat roof. If the proposed device actually worked, the recordings would be dominated by these noises.

I didn't think he was being serious on that point. I still don't.

occasionally cassettes did produce a lot of print-through, but not often. That issue disappeared by the early 80s

I never liked DNR, dolby B or C.

NT

I wonder if something similar could be used to self diagnose sleep apnea

dolby only reduced hf, and print-through had reduced hf due to the tape thickness

thankfully Dynamic Noise Reduction was Not Resuscitated once dolby came along.

NT

It doesn't matter what you or I think. He thinks that he is serious.

Yep. It was noticeable with very thin C-90 (0.4 mils thick) and C-120 (0.24 mils thick). Wikipedia claims that there were C-180 tapes, but I never saw any of those:

Dolby Labs is projecting for fiscal year 2019: "Total revenue will range from $1.23 billion to $1.25 billion." "Gross margin percentages will be approximately 87 percent on a GAAP basis." One might suspect that the GUM (great unwashed masses) are quite willing to purchase products with Dolby noise reduction technology.

You could definitely monitor snoring and gasping by listening, but when I was diagnosed with sleep apnea five years ago the best device I found to monitor my progress was the CMS 50D Plus fingertip pulse oximeter. Logs pulse and O2 saturation once a second as long as the batteries last (up to

It does. It's called a "Smart Phone". They're sometimes used to diagnose sleep apnea.

I didn't read the thread far enough.

I would put it the other way round

Multiband noise gating is the way to go now. Dolby must be into something else these days.

NT

Recording tapes with Dolby 'on' and replaying them with it 'off' gives a worthwhile boost to the highest frequencies for gentlemen over a certain age.

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I did that for many years. It means hf is lost at higher volumes. Dolby B&C are history now with multichannel noisegating, there's just no comparison.

NT

For quality of sleep statistics try the SnoreLab app for the iphone. Identifies snoring, apnea, REM sleep, etc.

Sampson CR-3 is about $120 USD and is switchable between cardioid/omni and has a 3 position (IIRC) filter switch to change roll-off characteristics. Shock mounts are available for it.