Why Is High Feedback Considered Bad In Audio? In Simple Terms

Dunno. A truly monotonic waveform might get pretty exciting, if you wait long enough.

Feeding trolls is a capital offense.

...Jim Thompson

Exactly, but if you're the average female punter hoping to improve her appearance, claims like that might *seem* to mean something.

Sylvia.

Yep. My thoughts exactly. A truly monotonic waveform would be forever increasing (or decreasing) until something "flashes" ;-)

...Jim Thompson

Like erf(x)? You might wait awhile for the flash.

;)

Cheers,

Phil Hobbs

It's about 5% less "pure oxygen" than fresh air. Prevents spoilage, perhaps?

Best regards, Spehro Pefhany

...and *then* gets really exciting. ;-)

True, I suppose even an RC is monotonic (and monotonous).

Or a simple R-C discharge. It gets pretty dull pretty fast.

John

Yeah, but some wiseacre would be bound to point out that it either has a (nonmonotonic) turn-on transient or comes from a very exciting past. ;)

Cheers,

Phil Hobbs

Yup, somebody will be pickey that way.

OK, how about an RC charge?

John

That is a far different definition than normally used. Compare with the IEEE dictionary definition.

But monotonic is a different property than ringing. There is no mathematical relationship.

And likewise if the LPF does not ring the HPF does not ring.

Don't be too quick to condemn. There are a heck of a lot of snake oil salesman out there. "Our speaker wire is sung to by virgins in an oxygen free atmosphere" etc. They are good for a laugh from time to time "Emperors new clothes" style.

But not everything in the audiophile realm is entirely hocus pocus. There is some real engineering too.

The final mechanical transducers that turn electrical signals into vibrations in the air are less than ideal loads and sufficiently imperfect that some do sound a lot better in a real room than others. And certain unlucky combinations of speaker and amplifier can sound awful or even be marginally unstable. When you get to a system where sound engineers mistakes become noticeable it probably isn't worth going beyond that unless the objective is to waste money. Biwired amplifiers make some sense from a network point of view.

What's harmful about opera tickets? I'll have any you are throwing out.

I suppose it depends what you call high end. There is a stratospheric audiophool price ceiling if you are so inclined. But it is worth having decent speakers and a better than average amplifier if you like music. A fairly good system test is some music you know well. And if you happen to know something like the minimalist Philip Glass composition Songs from Liquid Days then Track 2 will easily separate the sheep from the goats.

I was suprised to find that almost no sensibly priced home cinema systems could render it accurately. Detail was lost and the instruments became muddy and the tempo less well defined. Minimalist music is rather good for this sort of thing because the short repetative themes allow for easy and quick comparisons. And it falls apart if the timing isn't accurate.

Regards, Martin Brown

I don't have any particular project in mind at the moment. I was just interested to know if semiconductors had caught up with valves on all fronts or whether there was a niche where they still had the advantage.

On a sunny day (Mon, 26 Jan 2009 01:47:00 -0800 (PST)) it happened Martin Brown wrote in :

Add 'detail' to the list.

Add 'muddy' to the list.

Add 'tempo less well defined' to the list.

Add 'Minimalist music' to the list.

F*cking H*ll now the amplifier changes the timing. Wel I guess with a digital preprocessor it can.

LOL

Just hope you were kidding.

magnetrons are still king in microwave ovens :)

And some of them do. Try it and see. I suggested an experiment. Don't take my word for it. Home cinema systems seem to do a lot of digital processing internally now. The effect is not especially subtle so you don't need magic ears to hear the difference. Same speakers, same CD transport, different amplifier and an A B switching test.

No I was trying to point out that some music is rather more demanding of kit that others.

I can't believe that all electronics engineers have damaged hearing.

Regards, Martin Brown

On a sunny day (Mon, 26 Jan 2009 06:39:37 -0800 (PST)) it happened Martin Brown wrote in :

Well, there is 'latency' in digital processing, but variable latency?

Much of 'wow' and timing perception in pure imagination. Part of my job once was to measure that stuff (wow and flutter) on broadcast equipment. Wait until you heard a 'magnetocord' (film had perfo tape running in sync) coming up to speed. And I suffered from that imagination at one time or other myself, thinking to hear the speed variations in a crsytal controlled turntable...

What we did was use a single tone, and a frequency discriminator, to measure speed variations. No space for imagination. The meter shows it, or not.

That is true, these day my speakers are so bad that I am used to hearing distortion... That is, I use my Senheiser headphones HD201 if I need quality... And even those have a distinctive sound, but you get used to it rather quickly.

As you probably know the only one with perfect hearing here is Eyore ;-)