What a difference 10Hz makes.

[boater sam]

Sitting out here in the land of massive sound systems, Philippines, I notice the 60 Hz hum off said noise makers when not blasting out drum and bass or rap crap is more intrusive than 50Hz.

But I suppose it is really 120Hz I hear as opposed to 100Hz assuming that full wave rectification is used. They will be all semiconductors, they know not what a valve is here.

Anyone else found that 10Hz  or 20Hz makes a difference? I always thought I was tone deaf,,,,,,pardon?
I may be if I can't get away from this racket!

Sam.

[ppppenguin]

I'm not surprised. The ear's sensitivity is on a pretty steep slope at low frequencies: https://en.wikipedia.org/wiki/Equal-loudness_contour

[Terry]

I always used to notice how much more intrusive 60Hz hum was on US news clips on TV but they seem to have cleaned up their act these days, though.

[colly0410]

Surprised me how the 10 Hz difference in the frame frequency between UK & USA TV's was so noticeable first time I went to America in 1989, their pictures seemed so much steadier. When I came home our TV seamed to flicker for the first few days back.... I went to America a few months ago & all TV's I saw were plasma or LCD so noticed no difference...

[Richard_FM]

One oddity I noticed when I was last in the USA in 2008 were that the picture quality during commercial breaks dropped quite a bit compared to the actual programming.

This probably wasn't helped by the hotel distribution system, but sometimes it looked like the adverts had been shot with the same film stock used for the Sweeney.

[ppppenguin]

I went to America a few months ago & all TV's I saw were plasma or LCD so noticed no difference...

You wouldn't see a difference with LCD screens because they inherently have no large area flicker (Zero order hold function - the cells retain their previous state until switched again). Plasma screens will have large area flicker unless frame rate multiplication is used, and that's unlikely for what is now an old technology.

[boater sam]

Parrots can only watch LCD screens.

[Terry]

One oddity I noticed when I was last in the USA in 2008 were that the picture quality during commercial breaks dropped quite a bit compared to the actual programming.

This probably wasn't helped by the hotel distribution system, but sometimes it looked like the adverts had been shot with the same film stock used for the Sweeney.

Could this have been served by a small local affiliate station who inserted local adverts using less than perfect equipment? The quality of some US TV could be dire.

I've probably mentioned this before but here goes. In 1968 we were installing a Dynatron colour set one afternoon. The usual test card on BBC2 had been replaced by a live broadcast by satellite of Bobby Kennedy's funeral. Fortunately, the lady of the house busied herself elsewhere because the picture quality was not a good advert!

In one lengthy sequence the camera was positioned behind the motorcade as it proceeded along a straight country road. All the cars had their lights on which highlighted the abysmal setup of the camera because the red tube was so badly misaligned that the cars had one rear light whilst a ghostly line of red lights proceeded gracefully along the fields alongside the road!

[Richard_FM]

One oddity I noticed when I was last in the USA in 2008 were that the picture quality during commercial breaks dropped quite a bit compared to the actual programming.

This probably wasn't helped by the hotel distribution system, but sometimes it looked like the adverts had been shot with the same film stock used for the Sweeney.

Could this have been served by a small local affiliate station who inserted local adverts using less than perfect equipment? The quality of some US TV could be dire.

It had crossed my mind that the adverts were locally inserted, I was in Nashville, Memphis & New Orleans when I noticed this.  It was just before the digital switchover in the USA so possibly some older analogue equipment was still in use, & not being maintained much as it was due to be taken out of service.