3 dB bandwidth

But you only believe in *power* dBs !

Are you suddenly accepting the voltage dB now ? Indeed it is the norm.

In an op-amp data sheet, little difference.

In an audio line receiver the world of difference.

Graham

AES-R2-2004 - also see the referenced IEC standards.

AES-R2-2004: AES project report for articles on professional audio and for equipment specifications -- Notations for expressing levels (Revision of AES-R2-1998)

Printing Date: 2004-02-04 Publication History: Pub. 1998; Rev. 2004

Abstract: This document describes the style for levels standardized in IEC

Graham

Impressive! Out of 33 technologies listed, I had heard of 29 and actually worked with 19.

Guarded shields are especially cool -- especially when you set the gain wrong and introduce negative capacitance. :)

I have used sapphire insulators for electronics, and I have used optically-polished sapphire for optical work, but I cannot figure out why someone would want to optically-polish a sapphire insulator. Care to shed some light on the subject?

"The most hostile group was the one with high but unstable self esteem. These people think well of themselves in general, but their self-esteem fluctuates. They are especially prone to react defensively to ego threats, and they are also more prone to hostility, anger and aggression than other people.

"These findings shed considerable light on the psychology of the bully. Hostile people do not have low self esteem; on the contrary, they think highly of themselves, But their favorable view of themselves is not held with total conviction, and it goes up and down in response to daily events. The bully has a chip on his shoulder because he thinks you might want to deflate his favorable self image."

-Roy F. Baumeister, _Evil: Inside Human Violence and Cruelty_ p 149

That would be *you* then trying to assert that *only* 'power decibels' are the true ones, the light and the path ! Quoting utter jibberish in your pursuit of this.

See my post - the truth about decibels

Unlike closed minded, backward thinking idiots such as yourself, I'm perfect happy to accept that usage of dBs for voltages or powers ( or indeed SPL - where most ppl come across it everyday life ) is equally valid.

Graham

Well.... if you can't bring yourself to use 'fractional dBs' I guess that's your problem !

I normally specify the 'passband' of the audio gear I design as +0 / -

In short I'm offering a 'passband' that's 12x better than the usual plus

- minus 3dB that comms ppl use.

They would also find old buffoons like you hilarious. Do you wear carpet slippers and smoke a pipe too ?

Graham

As is F=ma

You are certainly entitled to your opinions. For the majority of us pro enginers, dBs are the most appropiate for many specifications.

Complete nonsese. 1.0000001 db is just as accurate as 1.122018467.

I agree that for many uses dBs are not optimum, but to state that a blanket "it is more appropriate to always use something else" shows complete naivety in practical electronic engineering. One uses the most appropriate terms for the job in hand.

Sure, dBs compress a range of values. That's what there are designed to do. In many cases that gives as a *better* handle on what is going on. For example, the classic ear response. Discussing hearing in non dB terms would be daft.

No one is claiming that dBs are always the best, but often they are.

Kevin Aylward snipped-for-privacy@anasoft.co.uk

Gosh! A linear accuracy of +0 / -5.5% no less.

Ordinary instrumentation works in the 0.1% to 0.5% region.

What do we get if we work say 1000, 1001, and 1005 to the same resolutions in 'fractional dBs'?

We have to use 60, 60.009, and 60.04.

Oh yes, 'fractional dBs' look far more convenient.

More personal insults Graham? Still I suppose it helps to disguise that you haven't yet posted the number you seem to be so shy of. Here's some help with the dB calcs that you are supposed to be expert in.

On Tue, 28 Jun 2005 00:12:14 +0000, Guy Macon wrote in Msg.

This was one of the points that triggered my "high end audio marketing" crack.

robert

Typically, a power of 10. It has to do with scientific notation, using the exponent-mantissa form of expression - each increase/decrease of the exponent (of 10) is an increase/decrease of an order of magnitude.

That other guy who said "20 dB" is just goofing around. It's 10 dB.

In a word, Ten times. (well, two words, but you get the point, I hope.)

Hope This Helps! Rich

Yeah, but if dBm is dB with respect to a milliwatt and dBV is with respect to a volt (or maybe a way of announcing that we're dealing with voltage ratios, hence the 20X rather than 10X log blahblah), what's the dB% character for "sound pressure level" - dBA? Decibels with respect to absolute?

Absolute what?

Thanks, Rich

^^^^^^^^^^^^^ - verb?

^^^^ than ^^^^ fewer (and we all know about the preposition at the end of the sentence.)

^^^^^^^^^^ reasonably

^^^ It's - the contraction _does_ use the apostrophe.

^^^ have ^^^ It's

^^^^ you're ^ ;

Yeah, but I still wish you'd class up a little and proofread your writings.

Thanks,

Will do. Before I start looking, let me take a guess at what I am going to find (if I find anything); I predict that they are using polished sapphire, not optically-polished sapphire, but the marketing dept. liked the sound of "optically-polished" better. I will report here if I find anything.

(And thanks for noticing that this is just the sort of thing I love researching!) :)

Thanks, I'll see if I can get hold of a copy - unless you can just post the relevant re-definition of the decibel from your own copy.

Interesting.... So 1V was never adopted as the reference and isn't being considered any more.

LOL !

Kevin's scribings are something else. The content is usually very good, the presentation leaves much to be desired.

In particular, why does he have to call them *resisters* < sic > ?

Graham

Please don't interpret this as in any way supporting anything a pest like Pooh Bear writes (when he decided to live a life of substituting personal attacks for a evidence, logic, or even discussing the topic at hand, he become unworthy of being included in "the audio fraternity" or any other segment of civil society), let me point out that the old saying "measure with micrometer, mark with chalk, cut with axe" seems to apply here. The transducers on both ends of the audio chain (microphones and speakers) as well as the acoustic environment they are in makes the sort of precision used in ordinary instrumentation overkill.

Speaking as someone who has designed "audio gear" that went into production and who makes the Los Angeles AES meetings whenever I can get free from paying work, I would very much like to see a list of this "audio gear" that out anonymous ursine killfile inhabitant claims to have designed.

Those Los Angeles AES meetings are pretty much composed of the age range that this maladroit coprophage chooses to insults. They would, of course, eat him for lunch if he tried his antics there. I suggest killfiling him and letting him shout into an empty hall.

except

unit

"Power of 10" smacks of speciesism. Or decadigitism, at least. Wouldn't "power of 2" be more natural?

Actually, thinking about it, I guess a power of e would be most natural.

are

dBA => measured with characteristic curve A dBC => measured with characteristic curve C

Yes, I wouldn't disagree with a pragmatic view. Although this sub-thread happened to start with the use of dB to spec the CMRR of instrumentation amplifiers.

Yes, it has become boring......

I'll shut up.