a curiosity, theoretical kinda' thing.

[soundguruman]

I don't have this book. But the light in which it is suggested sure makes it seem interesting.

It's "the bible of electricity..."

The standard textbook of electricity is used by everybody from bench techs to lineman, to nuke plant workers.
It has all the formulas, and all the terms, and all the theory, and starts with the simplest most basic explanations...

ALL AC electricity originates with a magnet and a coil of wire, just like the construction of a speaker. This book will take you into the most fundamental principles of AC generation, and you can break it down step by step.

For $10, you can find the answer or formula for almost anything.

Also, appropriately, the book gives credit to Tesla, not Edison, for conceiving our modern electrical grid system and three phase power...
(it's about damn time)

So, I guess the answer to the question is YES, if the speaker moves in and out at a regular rate, you could actually measure a sine wave at the terminals of the voice coil. so in a way, you could call the speaker a microphone or a transducer, if you have the external acoustic force to move the cone...

The coil of wire, moving in the magnetic field, produces a detectable amount of current...and if the coil is moving at a regular repetitive rate, you can for sure measure a sine wave across the coil.

[tonequester]

tonequester here.

I can get the book off of the internet about 10 or 12 bucks for sure. I'm with you on the older style textbooks. I'm going to check my local "Half Price Book Store" before I
order one. I think that it would complement the 1957 ARRL handbook that Madkatb sent me. The new stuff completely blows off vacuum tube technology, for the most part. I've got about 100 lbs. of books to trade in, and I wpuldn't be too surprised that "Half Price" has the book. They seem to end up with a lot of older science related books. I've gotten some real gems, including an old RCA tube manual. I appreciate keeping me in mind for a good book. When it comes down to reading for educational purposes, I'd rather "curl up" with a book than spend
hours staring at this screen, although you can't beat the WEB for quick look up, and reference. Thanks again my friend. You're a "Yanker", but you are one of the good ones !
tonequester.

[tonequester]

tonequester here.


Thanks soundguruman for the thumbs-up , and the added info on the "Bible of electronics". Sounds like it's not only a great textbook, but a must have referenceIf they.
I'm headed to "Half Price Books". If they don't have it, I'll order it ! Thanks for the reply man ! Have a "good'un" ! tonequester.

[Mark Hammer]

32 ohm speakers are nopt common, but they are out there. The 8x10 AMpeg cabs used 32 ohm drivers. I have one on my shelf. A driver, not a whole 8x10 cab.

I have a bunch of those wonderful little 2-1/2" foam-surround big-ass magnet speakers removed from old Macintoshes that measured 64 ohms!*** So yeah, well aware things exist above the 16R ceiling. They just happen to be much less common.

***A long-defunct surplus place near me used to regularly get in palettes of Macs from busibnesses and "render" them down to parts, selling those speakers for a buck a pop. I picked up a dozen or so. I really want to put together a little ported full-range cab with a quartet or sextet of them. In a proper cab, they probably have the same usable bandwidth as those old little Videotones.

[tonequester]

tonequester here.


Thanks for sharing about the 64 Ohm, 2&1/2" speakers. As long as I,ve been scrappoing/scrounging, and I've never run onto any speakers rated at 64 Ohms other than headphone speakers. I'll bet that 6 in a good cab could produce a pretty fair sound. At a dollar a speaker into 4 cabs, you've got a room full of sound for less than the price of a cheap set of phones. Where the Hell am I when all of the great deals on surplus parts quickly come and go ? Have a good'un ! tonequester.

[Enzo]

On the other end of the scale there are those little 3 inch drivers from the Bose 801 speakers. They are wired in series and are 1 ohm each.

[Austin]

Hey Tonequester, Eminence would rebuild that speaker like new if you call em up and mail it to them. Pretty cheap too.

I wish I had some 64 or32 ohm speakers, could make a little cabinet with them all tied in series and build a push pull circlotron guitar amp with no output transformer! Fun stuff!

[tonequester]

tonequester here.


Thanks for the re-cone idea for the Eminence, 12" x 32 Ohms. I had figured a recone would be at least 80% of the price of the speaker. I must admit that I'd never checked that option out. I'll give them a call od e-mail to get an estimate. Other than the small hole in the cone, it's brand new. It's seems me that I took it out of a new amp and put my own choice of speaker in right after I bought it. I'm certain that it's never been played. That was in 1982, so it's 30 years old N.O.S.(not counting the patched hole). Good idea if reasonably priced.
Thanks for the idea man ! Have a good one tonequester here.

[DrGonz78]

Well think of the Polytone Mini Brute II that has a 12" heavy duty speaker and runs 3ohms at 100 watts. Now that amp is the best solid state amp that I have ever heard!!! It's the speaker that makes the magical sound of the amp, well it's more than half the battle... sometimes...

[Austin]

Well think of the Polytone Mini Brute II that has a 12" heavy duty speaker and runs 3ohms at 100 watts. Now that amp is the best solid state amp that I have ever heard!!! It's the speaker that makes the magical sound of the amp, well it's more than half the battle... sometimes...

+1
On the other end of this, the very sensitive speakers I use enable single ended 3 watts of tube power to be loud enough to play with a band. Of course if you connected them to a 100 watt amp they would probably blow in about 3 seconds...

A speaker with a 96 db rating is twice as loud as a speaker with a 93 db rating. So every three decibels louder is twice as loud as perceived by the human ear they say.

I use speakers with 100db or more to get the sound I like, with only a couple 2 or 3 watts they can get ear splitting loud.

[rjb]

A speaker with a 96 db rating is twice as loud as a speaker with a 93 db rating. So every three decibels louder is twice as loud as perceived by the human ear they say.

No, 3dB higher = twice the power.
What they say is that 10dB higher (10x power) is perceived as about twice as loud.

Perceptions of Increases in Decibel Level
Imperceptible Change	1dB
Barely Perceptible Change	3dB
Clearly Noticeable Change	5dB
About Twice as Loud	10dB
About Four Times as Loud	20dB

I use speakers with 100db or more to get the sound I like, with only a couple 2 or 3 watts they can get ear splitting loud.

Could you give some examples (preferably, with retail source)?
In another thread, someone is looking for a speaker to use with a small 9V battery powered amp, for busking and small cafe gigs.

[tonequester]

tonequester here.


Greetings DrGonz78. As weird as I am, i should not only be "pro",but I should be in the Hall of Fame(like your quote). You make a very good point concerning speakers
Dr. Put S--- speakers on the best amp monmey can buy, and you still got s---! I'm not nearly as up, on the state of the art of loud speakers as I should be. I am learning a lot here on the forum and speakers aren;'t the hald of it. I have to agree with your "formula" for a great speaker. I',ve never gone wrong with "heavy duty" and Lower Z. Unfortunately, this combination usually adds up to High bucks. I've never minded that so much if I got Great sound in return. I am starting to look at sensitivity and decibels more since joining the forum. YThat's what it's all about for me. I couldn't get such good info if I were to go back to school. One has to do a little sorting of things out here, but that keeps my Googling honed, and my library card up to date. Keep on CRANKIN" DOC ! Always good to here from you. Have a "good 'un" ! Stay cool if you can. tonequester.

[tonequester]

tonequester here.


I made a small 9V. powered guitar amp a while back using a 3W. Radio Shack amp module kit(velleman) and didn't want to go over the price of the amp module. i had some old non-powered computer speakers(polk audio). they were 16 Ohm and I wired them for 8 Ohm, which the amp kit recommended. I did not wire them for stereo, but for mono.
The Polks were heavy duty enough looking, but I had no power specs on them. The amp ended up being smaller than a shoe-box, and had surprising volume. Computer speakers that are now amplified may well be rated even higher. It may be worth a try if you have access to them. Good luck with your project. tonequester.

[Dave Mac Farlane]

Toney - can I recommend a subscription to 'Model engineer's workshop?
it is not a modelling journal, more like a fringe engineer's mag, and they cover electrics as well.
In fact, I would recommend it to anyone with a technical bent.
Just a thought.
Dave.