What goes through an Engineer's mind upon designing a loudspeaker? Surely there must be some general guidelines, no? Perhaps. Although this is most likely dependent upon the circumstances (cost, enclosure, available power, etc).
If these guidelines do exist, what are they. If you could order them, how would you go about doing it?
I need to design a loudspeaker around these circumstances:
Cost: FREE
Frequency Response: 20hz-20khz
Enclosure: Infinite Baffle (is it baffle or baffled?)
Available Power: .5 RMS
Okay, so this is a bit unrealistic. A full range driver capable of playing the whole spectrum? I'm not sure if that exists. Why IB? This speaker will be for a demonstration, so no enclosure! The .5 wrms is from the LM386. I'll just drive it with my Ipod.
Okay! So I need a loudspeaker with great sensitivity. Wait though, I thought sensitivity was how loud a drive could play without audible distortion (vaguely speaking). When people say "I need a driver that's really sensitive," does that mean they need one that's like 90db+ or a speaker rated at like 5wrms?
I'll stop here. I have no idea how large to make the cone, what angle should it have, what material to make it out of, etc. I assume that last part is up to the individual's taste (I prefer paper!). Btw, I have no idea why cone material affects the sound. I just see sound as a vibration of a medium. Regardless of how they're pushed & pulled, atoms are atoms, right? I have no idea how many turns I need, what AWG to use, the size of the voice coil. I have no idea what magnet to use, & what type (neo or that other one). I don't know whether I need a dust cap or not. I'm not sure how large to make the pole piece (or vent if you will).
^& why stop at the geometry of the cone in relation to the desired frequency response? You don't want a 40oz magnet with a 2" cone. ...lol, a ratio of a ratio.
Maybe I should just start with whatever kind of relation I need between the voice coil & the magnet?
I'm lost!
Thanks
*It seems to me that there are a LOT of give & takes when it comes to designing loudspeakers. For instance, you don't always need a 15" cone to get 30hz. Enclosure type plays a role here. I know there are 5" drivers capable of 30hz in the correct enclosure (like transmission line).
If these guidelines do exist, what are they. If you could order them, how would you go about doing it?
I need to design a loudspeaker around these circumstances:
Cost: FREE
Frequency Response: 20hz-20khz
Enclosure: Infinite Baffle (is it baffle or baffled?)
Available Power: .5 RMS
Okay, so this is a bit unrealistic. A full range driver capable of playing the whole spectrum? I'm not sure if that exists. Why IB? This speaker will be for a demonstration, so no enclosure! The .5 wrms is from the LM386. I'll just drive it with my Ipod.
Okay! So I need a loudspeaker with great sensitivity. Wait though, I thought sensitivity was how loud a drive could play without audible distortion (vaguely speaking). When people say "I need a driver that's really sensitive," does that mean they need one that's like 90db+ or a speaker rated at like 5wrms?
I'll stop here. I have no idea how large to make the cone, what angle should it have, what material to make it out of, etc. I assume that last part is up to the individual's taste (I prefer paper!). Btw, I have no idea why cone material affects the sound. I just see sound as a vibration of a medium. Regardless of how they're pushed & pulled, atoms are atoms, right? I have no idea how many turns I need, what AWG to use, the size of the voice coil. I have no idea what magnet to use, & what type (neo or that other one). I don't know whether I need a dust cap or not. I'm not sure how large to make the pole piece (or vent if you will).
^& why stop at the geometry of the cone in relation to the desired frequency response? You don't want a 40oz magnet with a 2" cone. ...lol, a ratio of a ratio.
Maybe I should just start with whatever kind of relation I need between the voice coil & the magnet?
I'm lost!
Thanks
*It seems to me that there are a LOT of give & takes when it comes to designing loudspeakers. For instance, you don't always need a 15" cone to get 30hz. Enclosure type plays a role here. I know there are 5" drivers capable of 30hz in the correct enclosure (like transmission line).
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You have too many conflicting constraints. I'd suggest you take a look at what is achievable with a few different designs then see how you can best meet a compromise of your needs.
And to answer one of your questions, a sensitive loudspeaker is one which does not require much electrical power for acoustic output, i.e. the dB per watt figure is high.
You are not going to be able to make a drive unit to compare with anything reasonable that you can buy, just build something that is easy for you to finish and see it as a learning excersise. Then build a bigger or smaller version, or use a different material or bigger magnet and see how that makes it perform differently.
And to answer one of your questions, a sensitive loudspeaker is one which does not require much electrical power for acoustic output, i.e. the dB per watt figure is high.
You are not going to be able to make a drive unit to compare with anything reasonable that you can buy, just build something that is easy for you to finish and see it as a learning excersise. Then build a bigger or smaller version, or use a different material or bigger magnet and see how that makes it perform differently.
And what about internal ( spider ) and external ( surround ) suspensions ?
The first is for making the former always in line; the second also keeps the cone centered and also follows the movement. Basically, the membrane should be stiff & light; most phase alterations that happen to be in a fullrange -though well engineered & executed- exist because the membrane isn't capable of following the signal and some modes of resonance take place along the cone. The very central part of the cone emits the treble because it's direcly attached to the former, going away from the center it's difficult for a big mass to vibrate at high frequencies. Then you see the pistonic working range given by the diameter and how it acoustically applies, so the dB and W and distance can relate each other.
I would start with a 5-10 W amplifier and a existing speaker.
Distortion made from an amplifier are unavoidable and a power reserve of 10 X would be welcomed- Same for the speaker.
The first is for making the former always in line; the second also keeps the cone centered and also follows the movement. Basically, the membrane should be stiff & light; most phase alterations that happen to be in a fullrange -though well engineered & executed- exist because the membrane isn't capable of following the signal and some modes of resonance take place along the cone. The very central part of the cone emits the treble because it's direcly attached to the former, going away from the center it's difficult for a big mass to vibrate at high frequencies. Then you see the pistonic working range given by the diameter and how it acoustically applies, so the dB and W and distance can relate each other.
I would start with a 5-10 W amplifier and a existing speaker.
Distortion made from an amplifier are unavoidable and a power reserve of 10 X would be welcomed- Same for the speaker.
I recently wrote a paper on the history of electricity. I broke it down like this,
1.) Thales discoveries with amber & lodestone
2.) 1st true electrical storage device (Galvani VS Volta)
3.) Discovery of electromagnetism (Faraday/Orsted)
4.) My conclusion was to give a practical application. I did this by explaining the workings of a crystal set.
I stopped just before the audion tube. We live in a wireless age. I wanted to show how it (wireless communication) all got started (radio).
I'm taking this a step further & giving a presentation. I figured I could bring in a microphone & show how mechanical waves (sound) can be turned (via mic) into an electrical signal (using o-scope) & how this electrical signal can thus be turned back (via loudspeaker) into a mechanical wave. The point I'm trying to get across is simplicity; anyone with a few household items (paper plate, fridge magnet, etc) can toss one together. Not sure how many people have magnet wire, ha.
I do not wish to purchase a completed loudspeaker. I'm an engineering student & am more interested in functionality.
1.) Thales discoveries with amber & lodestone
2.) 1st true electrical storage device (Galvani VS Volta)
3.) Discovery of electromagnetism (Faraday/Orsted)
4.) My conclusion was to give a practical application. I did this by explaining the workings of a crystal set.
I stopped just before the audion tube. We live in a wireless age. I wanted to show how it (wireless communication) all got started (radio).
I'm taking this a step further & giving a presentation. I figured I could bring in a microphone & show how mechanical waves (sound) can be turned (via mic) into an electrical signal (using o-scope) & how this electrical signal can thus be turned back (via loudspeaker) into a mechanical wave. The point I'm trying to get across is simplicity; anyone with a few household items (paper plate, fridge magnet, etc) can toss one together. Not sure how many people have magnet wire, ha.
I do not wish to purchase a completed loudspeaker. I'm an engineering student & am more interested in functionality.
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Yes...and Ohhh now I understand why you want to use the LM 386
Great amp BTW
So...talking about sensitivity and efficiency...the latter has got to be kept under control, as all the various parts have to be assembled and work at best.
All the assembly's got to be with minimum gaps and tolerances.
So, make the basket ...
Personally, I would disassemble some units from radios etc and use the already assembled former and voice coil > corresponding magnet, too.
Then, I would mix from other cones and baskets and see how it comes.
You can try also with old cheap headphones, using the membrane as the spider and tryng to attach it to a cone and a basket. You can substitute the spider with 3-4 tensioning rubberbands.
There was a thread some years ago with a chinese forumer showing this - he was very good with paper, makink very deep cones and using HP's magnet.
I lost the thread, then I recovered it some years ago ( a german member remembered it) then I lost it again
Great amp BTW
So...talking about sensitivity and efficiency...the latter has got to be kept under control, as all the various parts have to be assembled and work at best.
All the assembly's got to be with minimum gaps and tolerances.
So, make the basket ...
Personally, I would disassemble some units from radios etc and use the already assembled former and voice coil > corresponding magnet, too.
Then, I would mix from other cones and baskets and see how it comes.
You can try also with old cheap headphones, using the membrane as the spider and tryng to attach it to a cone and a basket. You can substitute the spider with 3-4 tensioning rubberbands.
There was a thread some years ago with a chinese forumer showing this - he was very good with paper, makink very deep cones and using HP's magnet.
I lost the thread, then I recovered it some years ago ( a german member remembered it) then I lost it again
Hi,
Imagining something is very simple is not the same as knowing it simply isn't.
Try knocking up a speaker with no cabinet, a paper plate, some wire, a
fridge magnet etc and see how you get on. Very badly I would assume,
as I would and I've got a very good idea of what I would be doing.
No enclosure is open baffle, infinite baffle is wall mounted between rooms
and also a misnomer applied to describing sealed box loudspeakers.
You can't just toss a speaker together, or a microphone for that matter.
The history of Communications, which leads to our "wireless world" is
not a simple as the history of Electricity, though very intertwined.
rgds, sreten.
BTW - 3) Discovery is Orsted And Ampere, Faraday is a decade later.
Imagining something is very simple is not the same as knowing it simply isn't.
Try knocking up a speaker with no cabinet, a paper plate, some wire, a
fridge magnet etc and see how you get on. Very badly I would assume,
as I would and I've got a very good idea of what I would be doing.
No enclosure is open baffle, infinite baffle is wall mounted between rooms
and also a misnomer applied to describing sealed box loudspeakers.
You can't just toss a speaker together, or a microphone for that matter.
The history of Communications, which leads to our "wireless world" is
not a simple as the history of Electricity, though very intertwined.
rgds, sreten.
BTW - 3) Discovery is Orsted And Ampere, Faraday is a decade later.
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LM386; you should have seen the line array I completed with the $1 Parts Express buy outs. Those things dropped bottom while bottoming out, lol.
I have a Lepai 2020 that I will be utilizing for my demonstration. I believe it puts out 15wrms/ch which should be sufficient.
Confining 2000 years of electrical & magnetic phenomena into a 2 page double spaced paper isn't an easy task. I'm really struggling to put together a thesis statement,
"...spark a revolution in wireless communication..."
What would? Electromagnetism of course. & where does the invention of the battery fall into place? How about hertzian waves?
I recently read a book called "The Battery." I believe his thesis went something like this,
"What began as a long running dispute in biology over a dead frog's leg would...."
I'll let you assume the rest. I thought about starting with Thales, but that wouldn't be fair to state amber & lodestone were just two manifestations of the same thing. Amber; that's the electrostatic force. I'll just leave it as them being both problematic to the ancients.
ugh, well here's the start of my paper,
We're all familiar with it; the hair on your hood straight from the dryer, a tingle on the tongue, the sudden discharge of a door handle after a swift walk across the wintry carpet floor. It's a mysterious force -electricity. Tales of it's (blank) date as far back as Ancient Greece.
^Now I'll briefly go over Thales & his discoveries with amber & lodestone. Then I need a thesis. Again, my paper needs to be short.
Any ideas on a thesis? Again the point of my essay is to give a little back round on how radio (wireless communication) all got started.
I have a Lepai 2020 that I will be utilizing for my demonstration. I believe it puts out 15wrms/ch which should be sufficient.
Confining 2000 years of electrical & magnetic phenomena into a 2 page double spaced paper isn't an easy task. I'm really struggling to put together a thesis statement,
"...spark a revolution in wireless communication..."
What would? Electromagnetism of course. & where does the invention of the battery fall into place? How about hertzian waves?
I recently read a book called "The Battery." I believe his thesis went something like this,
"What began as a long running dispute in biology over a dead frog's leg would...."
I'll let you assume the rest. I thought about starting with Thales, but that wouldn't be fair to state amber & lodestone were just two manifestations of the same thing. Amber; that's the electrostatic force. I'll just leave it as them being both problematic to the ancients.
ugh, well here's the start of my paper,
We're all familiar with it; the hair on your hood straight from the dryer, a tingle on the tongue, the sudden discharge of a door handle after a swift walk across the wintry carpet floor. It's a mysterious force -electricity. Tales of it's (blank) date as far back as Ancient Greece.
^Now I'll briefly go over Thales & his discoveries with amber & lodestone. Then I need a thesis. Again, my paper needs to be short.
Any ideas on a thesis? Again the point of my essay is to give a little back round on how radio (wireless communication) all got started.
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The first things that come to mind are piezo electricity ( for pick ups)
and quartz for oscillators.
For loudspeakers and their origins, take a look here http://www.leradiodisophie.it/Spillo.html
and quartz for oscillators.
For loudspeakers and their origins, take a look here http://www.leradiodisophie.it/Spillo.html
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You're inadvertently on the right track. You could research what the not-so-ancients (Kellogg and Rice at Bell Telephone in the early 1920's) had to choose between when they were looking to design the first loudspeaker and found that they were doomed to go down the black magic path of magnetics and cones...?
I wouldn't get too caught up on the history of electricity and such for while electricity is an obvious component in a radio's function, the history of electricity is a bit of a red herring when it comes to the history of radio, if you ask me.
If you're focusing on the history of radio, then I'd start by trying to articulate what it was that prompted people to begin the kinds of study, research and experimentation associated with the invention of radio in the first place. What kinds of questions were they trying to answer? Did they have some vague yet promising vision in mind, or were they trying to solve some specific problems? That's where I'd start because while awareness of the phenomenon of electricity may have been around for a long time, the history of radio per se begins when people start to look at electricity in a new and different light, e.g. as part of some vague but promising vision, as a possible means of solving some specific problem, and so on. Look at what was motivating the early innovators and experimenters in radio and I bet you'll find your thesis there.
If you're focusing on the history of radio, then I'd start by trying to articulate what it was that prompted people to begin the kinds of study, research and experimentation associated with the invention of radio in the first place. What kinds of questions were they trying to answer? Did they have some vague yet promising vision in mind, or were they trying to solve some specific problems? That's where I'd start because while awareness of the phenomenon of electricity may have been around for a long time, the history of radio per se begins when people start to look at electricity in a new and different light, e.g. as part of some vague but promising vision, as a possible means of solving some specific problem, and so on. Look at what was motivating the early innovators and experimenters in radio and I bet you'll find your thesis there.
As they say over here, Here's one I made earlier.
This is a demonstration of how a loudspeaker works and can be assembled when needed.
Needs some copper wire. paper, card, glue and sticky tape and a few small neodymium magnets.
Wind the coil on a paper former large enough to slip over the magnets, the more wire the better upto a point - mine is @ 0.6 ohm so needs a resistor in series to stop me melting my amp! If this is 4-8 ohms then you can connect direct.
Suspension is by sticky tape from the paper tubes
Its inefficient, distorts, but demonstrates the principle.
This is a demonstration of how a loudspeaker works and can be assembled when needed.
Needs some copper wire. paper, card, glue and sticky tape and a few small neodymium magnets.
Wind the coil on a paper former large enough to slip over the magnets, the more wire the better upto a point - mine is @ 0.6 ohm so needs a resistor in series to stop me melting my amp! If this is 4-8 ohms then you can connect direct.
Suspension is by sticky tape from the paper tubes
Its inefficient, distorts, but demonstrates the principle.
Attachments
And your working design for a demonstration unit from the scrap box
Hi,
That I don't have one doesn't mean I wouldn't know how
to build one, incorporating the basic fundamental principles
used in nearly all driver designs, and as such as a teaching
tool it would be far more useful than something that works
very poorly because no appropriate principles are used.
I'd have teaching field day giving students 9 neo magnets *,
saying you need steel pole pieces, a coil, a cone and some
form of suspension, go off and try to build a loudspeaker.
Only those who really know their stuff would make any sense of it.
Only the really brilliant would do most things right, very unlikely.
rgds, sreten.
* in this case disc plate magnets, N/S across the discs.
Though an an exercise its never going to happen, its too
difficult in concept at the level I teach stuff to students.
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For God's sake, Sreten.
You can be certainly counted on to produce a bitter comment about anything.
As a demonstration device, it's fine.
As of what could pupils learn from it, it will be as much as from a properly designed speaker, even a commercially built one, that's to say NOTHING if left on their own, simply because most Electrical phenomena are not at all self-evident (as, say, Mechanical phenomena are).
Electricity, magnetism and a host all other Fields are invisible to the naked eye, yet they are real and can be explained.
Teacher's commitment and ability to explain is the key here, and since I very much doubt you were in Spiny's class, don't know how you may have the gall to comment unfavorably on what was taught there.
If anything, build a working example, write an explanation and post them here.
Then let others decide.
Regards
You can be certainly counted on to produce a bitter comment about anything.
As a demonstration device, it's fine.
As of what could pupils learn from it, it will be as much as from a properly designed speaker, even a commercially built one, that's to say NOTHING if left on their own, simply because most Electrical phenomena are not at all self-evident (as, say, Mechanical phenomena are).
Electricity, magnetism and a host all other Fields are invisible to the naked eye, yet they are real and can be explained.
Teacher's commitment and ability to explain is the key here, and since I very much doubt you were in Spiny's class, don't know how you may have the gall to comment unfavorably on what was taught there.
If anything, build a working example, write an explanation and post them here.
Then let others decide.
Regards
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