Ohms... What the hell !!!

[flyfisher]

[quote name='Mr. Foxen' post='1361341' date='Sep 3 2011, 09:23 PM']And cabs is nominal impedance anyway, so isn't really impedance,[/quote]

[pendantry mode]
Almost. Impedance is impedance. There's nothing particularly special about loudspeakers. The 'nominal' refers the fact that the actual impedance is dependent on the frequency and will vary across the audio spectrum.

It's a bit like doing a 'nominal' speed of 60mph on a motorway. Sometimes it might be 58mph, sometimes it might be 61mph, but it's close enough to be called 60mph.
[/pedantry mode]

[Tait]

[quote name='derrenleepoole' post='1359687' date='Sep 2 2011, 11:40 AM']Yes, but the guy wanted simple, layman's terms. You're clearly way more capable than me at grasping the full mathematics of what is required, but not everyone needs that. Start simple for now, get more complicated as your experience improves. Laying on a full barrage of mathematics is likely to be more confusing than helpful - even though it is helpful [/quote]

You're right! I edited out the equation bit pretty much straight after posting because I realised the OP wasn't mixing 8 ohm and 4 ohm cabs anyway, it was irrelevant.

[quote name='Mr. Foxen' post='1361341' date='Sep 3 2011, 09:23 PM']Mileage. The impedance thing is more importantto differentiate it from resistance. And cabs is nominal impedance anyway, so isn't really impedance, 'ohmage' is probably better thought of as a term meaning 'nominal impedance as applied to speakers'.[/quote]

This is one thing I never understood, whats the difference between impedance and resistance? From all the definitions of impedance it sounds like it's exactly the same as resistance to me.

EDIT: Actually, I think I get it now. Essentially for a DC circuit they're identical in every way, but for AC the impedance takes into account the phase difference between the current and potential difference?

Edited September 4, 2011 by Tait

[Mr. Foxen]

[quote name='Tait' post='1362423' date='Sep 4 2011, 11:19 PM']EDIT: Actually, I think I get it now. Essentially for a DC circuit they're identical in every way, but for AC the impedance takes into account the phase difference between the current and potential difference?[/quote]

Impedance needs a frequency to be specified, and has resistive and capacitive components, which I don't really understand, but a capacitor can pass AC but not DC, hence their using in amps, and a sort of important thing when figuring how stuff works.

[bobbass4k]

Resistance is for DC circuits, Impedance is the same concept (resistance to electron flow) but for AC circuits. There's little to no conceptual difference, just terminology.

[quote name='Jack' post='1361329' date='Sep 3 2011, 09:17 PM']Whilst we're being educational, the word is 'impedance', not 'ohmage' or anything else of the like. You don't say 'kilometreage', you say 'distance'. One is the measurement and one is the unit.


(I guess for some reason we do say 'footage' when measuring distance or area but I digress.)[/quote]

Amperage is used for current, Voltage is used for, err... Voltage, Wattage is used for power, Ohmage seems fairly acceptable.

[Mr. Foxen]

[quote name='bobbass4k' post='1362501' date='Sep 5 2011, 01:15 AM']Voltage is used for, err... Voltage[/quote]

Isn't that one potential difference?

[bobbass4k]

[quote name='Mr. Foxen' post='1362503' date='Sep 5 2011, 01:17 AM']Isn't that one potential difference?[/quote]

It's called loads of things, Voltage, Potential Difference, Electromotive Force, Electrical Tension, (some are subtly different concepts but basically the same thing). Current is actually electrical current density, or conserved charge flow desnity, there's so many different names and terms for these things, that's kind of my point.

[51m0n]

I dont understand the need or desire to dumb down the formula for impedance.

Firstly, it really is not complex, if you havent mastered fractions and simple algebra yet, and are an adult you should look into some evening classes to be honest.

Secondly you need to know and understand the simple formula so that you can work out for yourself if what you want to do with your kit will break it, without asking on here always. After all we arent there in the shop, on the gig with you to hold your hand always.

If it were some seriously complex mathematical formula then I could understand the need for a simplified version, but it isnt at all, and any simplification on it will not work properly.

If someone asks for something to be explainedsimply then I find stepping through the explaination carefully and accurately to more often than not be the best bet for everyone, if they then ask further questions about the detail thats fine.

Telling them the wrong answer because they asked for a simple explanation is patronising, stupid and prone to cause damage to their kit.

[xgsjx]

I thought there was a sticky that explains all this.

[url="http://basschat.co.uk/index.php?showtopic=135"]Pay homage to the ohmage.[/url]

[Happy Jack]

Yes, but getting back to the hosepipe and the magic smoke (which is what we're really interested in, after all) am I right in thinking that buying a blindingly expensive oxygen-free hosepipe and fitting it with gold-plated connectors will make my smoke even more magical?

[xgsjx]

[quote name='Happy Jack' post='1362570' date='Sep 5 2011, 08:32 AM']Yes, but getting back to the hosepipe and the magic smoke (which is what we're really interested in, after all) am I right in thinking that buying a blindingly expensive oxygen-free hosepipe and fitting it with gold-plated connectors will make my smoke even more magical?[/quote]
Not sure. But it will be shinier than your standard Hoselock jobs.