okay, so im gonna go to this lan in october, however, my headset is pretty good at blocking out the sounds around me.
so i came up with this idea.
basicaly, its a box with a little mic, that splices the mic sound into the headphones
so here is what i thought:
mic--preamp--headphoneamp--out
lineout from pc/playstation 3--headphoneamp--out
so three inputs and two outputs, left in right in and mic in, then left out and right out, (with mic on both)
i need to be able to adjust both the lineout volume and the mic volume independently.
heres my problem... how the hell do i do that??
so i came up with this idea.
basicaly, its a box with a little mic, that splices the mic sound into the headphones
so here is what i thought:
mic--preamp--headphoneamp--out
lineout from pc/playstation 3--headphoneamp--out
so three inputs and two outputs, left in right in and mic in, then left out and right out, (with mic on both)
i need to be able to adjust both the lineout volume and the mic volume independently.
heres my problem... how the hell do i do that??
Opamp circuits. There's one called a Summing Amplifier, which you can use to combine the signals from the mic and the line, for each channel. Upstream from those, you could have a buffer amplifier for each input. Somewhere in there, you can have a pot for each input's volume.
Go to National Semiconductor | High-performance Analog and download Application Notes AN-20 and AN-31. They contain schematics of the building-block circuits that you can use.
Remember to add decoupling caps on all of the opamp power pins.
Tom
Go to National Semiconductor | High-performance Analog and download Application Notes AN-20 and AN-31. They contain schematics of the building-block circuits that you can use.
Remember to add decoupling caps on all of the opamp power pins.
Tom
That's pretty-much correct. And each of the summing amplifiers would have an output.
But maybe I misunderstood what you were trying to do. Do you just want to listen to the mic OR the source, but not both at the same time? If so, you don't need to sum anything. You can just use a switch, right?
What does it take to drive those cans of yours? Do you know their impedance?
Download these, anyway:
http://www.national.com/an/AN/AN-20.pdf
http://www.national.com/an/AN/AN-31.pdf
But maybe I misunderstood what you were trying to do. Do you just want to listen to the mic OR the source, but not both at the same time? If so, you don't need to sum anything. You can just use a switch, right?
What does it take to drive those cans of yours? Do you know their impedance?
Download these, anyway:
http://www.national.com/an/AN/AN-20.pdf
http://www.national.com/an/AN/AN-31.pdf
Maybe you don't need to build anything. I don't know about PS3s but PCs normally gave a Mic input, so you could plug the microphone in there and let your sound-card do the mixing for you. The standard Windows "volume control" software has a mixer that lets you set the levels separately for various inputs etc.
What kind of microphone do you have? You're going to have to connect it to something somehow. BTW, speakers and headphones normally work as microphones too, so in a pinch you could use old walkman earphones or a spare headset or whatever you have lying around, if only for testing.
LTSpice is a simulator. It just predicts how a circuit will behave. It doesn't help you design the circuit or tell you what values to use.If you just want to put an inductor into a schematic, there's one on the toolbar in LTSpice, at least in my version.
What kind of microphone do you have? You're going to have to connect it to something somehow. BTW, speakers and headphones normally work as microphones too, so in a pinch you could use old walkman earphones or a spare headset or whatever you have lying around, if only for testing.
Au contraire, mon ami.
A simulator can be quite an excellent design tool!
Although I happen to have an EE degree and a little bit of design experience, not everyone is, or does. And I, for one, don't mind letting them venture into our club, even though in the good old days they wouldn't have had a chance in hell of getting in.
LTSpice can be VERY effective in helping to find what values to use. That's probably one of the things that I use it for the most, in fact. Of course, you have to know what you're wanting to optimize, first. But once it's down to one or two component values, LTSpice is often much easier and faster than calculating by hand. And if you make really good models, which include most or all of the parasitics, for example, and maybe even frequency- and temperature-dependent capacitors, etc, or whatever is needed for good-enough accuracy in a particular case, and especially if your circuit is not trivial, then LTSpice (or any simulator) can be much better and easier and faster than many other methods, for selecting optimal component values or other circuit parameters.
One simple example is the .step functionality. One can define a variable for almost any circuit parameter or component value, and then use a spice .step directive to sweep the variable through a range of discrete steps, and automatically make a series of overlayed plots of almost anything one desires, either something directly probe-able from the schematic or anything that is calculatable. Then, optionally, one could "zoom in" with another run over a range of steps between two of the points from the previous sequence of steps, to fine tune, ad nauseum.
One can even sweep two variables in one run, such that for each step of one, the other sweeps through all of its steps. What's not to love about THAT? (except maybe that it could enable a non-EE to eventually come up with something that works exceedingly well)
And a circuit simulator is also truly spectacular for designing a new circuit topology. Many times, I have wanted to come up with a new circuit to perform a particular function, and have used LTSpice to quickly and easily experiment, to test different methods and topologies I might dream up (or even just to compare some already-known methods).
AFTER ALL(!), as long as I'm drawing schematics and wondering if they'll do what I'm wanting, I might as well also be able to hit the "RUN" button whenever I want and see the response unfold in time or frequency!! That's certainly a hugely-helpful design aid, to which I can't see any significant downside.
By the way (and this part is NOT directed at godfrey, in any way), if anyone is going to start moaning about how you can't trust the simplified modeling or the over-precise results and about how people might be fooled into believing in simulations that are less than realistic or might rely on them inappropriately, or might not learn "the right ways" to analyze or design, etc etc etc, just save it (or, better yet, chuck it). Almost everyone else already knows that. Simulators are fantastically-useful tools. With all due respect to the late Bob Pease, if you don't like simulators, then I suggest that you simply assume that YOU have a flaw, not simulators in general and everyone who uses them.
Tom
What kind of microphone do you have? You're going to have to connect it to something somehow. BTW, speakers and headphones normally work as microphones too, so in a pinch you could use old walkman earphones or a spare headset or whatever you have lying around, if only for testing.
Au contraire.
A simulator can be quite an excellent design tool!
Although I happen to have an EE degree and a little bit of design experience, not everyone is, or does. And I, for one, don't mind letting them venture into our club, even though in the good old days they wouldn't have had a chance in hell of getting in.
LTSpice can be VERY effective in helping to find what values to use. That's probably one of the things that I use it for the most, in fact. Of course, you have to know what you're wanting to optimize, first. But once it's down to one or two component values, LTSpice is often much easier and faster than calculating by hand. And if you make really good models, which include most or all of the parasitics, for example, and maybe even frequency- and temperature-dependent capacitors, etc, or whatever is needed for good-enough accuracy in a particular case, and especially if your circuit is not trivial, then LTSpice (or any simulator) can be much better and easier and faster than many other methods, for selecting optimal component values or other circuit parameters.
One simple example is the .step functionality. One can define a variable for almost any circuit parameter or component value, and then use a spice .step directive to sweep the variable through a range of discrete steps, and automatically make a series of overlayed plots of almost anything one desires, either something directly probe-able from the schematic or anything that is calculatable. Then, optionally, one could "zoom in" with another run over a range of steps between two of the points from the previous sequence of steps, to fine tune, ad nauseum.
One can even sweep two variables in one run, such that for each step of one, the other sweeps through all of its steps. What's not to love about THAT? (except maybe that it could enable a non-EE to eventually come up with something that works exceedingly well)
And a circuit simulator is also truly spectacular for designing a new circuit topology. Many times, I have wanted to come up with a new circuit to perform a particular function, and have used LTSpice to quickly and easily experiment, to test different methods and topologies I might dream up (or even just to compare some already-known methods).
AFTER ALL(!), as long as I'm drawing schematics and wondering if they'll do what I'm wanting, I might as well also be able to hit the "RUN" button whenever I want and see the response unfold in time or frequency!! That's certainly a hugely-helpful design aid, to which I can't see any significant downside.
By the way (and this part is NOT directed at godfrey, in any way), if anyone is going to start moaning about how you can't trust the simplified modeling or the over-precise results and about how people might be fooled into believing in simulations that are less than realistic or might rely on them inappropriately, or might not learn "the right ways" to analyze or design, etc etc etc, just save it (or, better yet, chuck it). Almost everyone else already knows that. Simulators are fantastically-useful tools. With all due respect to the late Bob Pease, if you don't like simulators, then I suggest that you simply assume that YOU have a flaw, not simulators in general and everyone who uses them.
Tom
yep, is it not just another very useful tool to have access to that gives us more insight into the designs in a preemptive manner, can it replace prototyping/breadboarding altogether? nope, but as Tom says, it allows you to run through a very predicable and repeatable set of parameters on a model that might be very tedious, expensive, or impossible to observe in this manner any other way. no one step should be trusted with all the weight, but its about utilizing the right tool for the job and knowing their limits.
I realize that this thread is not about LTSpice, but...
Another extremely-handy feature for design (or, analysis in support of design), in LTspice, is the "power dissipation probe".
For those who don't yet know, in LTSpice, when you've run a circuit simulation (or have started one running), then when your mouse cursor is in the schematic window, it turns into a voltage probe, or a current probe, depending on where you position it.
BUT, if you hold down ALT, it becomes a Power Dissipation probe! Not only can you Alt-click on each resistor, for example, to see their power dissipation plotted as a function of time (assuming you ran a transient analysis), you can also plot power dissipation for devices like opamps, transistors, diodes, and even the power supply powering the circuit!
It gets even better. After the sim is stopped, if you then hold down Ctrl-Alt and click on one of the power dissipation plots' headings, it will average and integrate (optionally over an interval you selected; otherwise over the visible part of the plot), giving you the average power dissipation (and the total joules). I LOVE being able to get the average power dissipated by every component, and every SUBSYSTEM, and the entire circuit, so darn easily!
Another fantastic feature is that you can use _WAVE FILES_, for inputs and/or outputs! The possibilities are exquisitely intriguing, to say the very least!
By the way, this software is a FREE DOWNLOAD!! (from linear.com) And there are tens of thousands of free downloadable models for components and devices.
Tom
Another extremely-handy feature for design (or, analysis in support of design), in LTspice, is the "power dissipation probe".
For those who don't yet know, in LTSpice, when you've run a circuit simulation (or have started one running), then when your mouse cursor is in the schematic window, it turns into a voltage probe, or a current probe, depending on where you position it.
BUT, if you hold down ALT, it becomes a Power Dissipation probe! Not only can you Alt-click on each resistor, for example, to see their power dissipation plotted as a function of time (assuming you ran a transient analysis), you can also plot power dissipation for devices like opamps, transistors, diodes, and even the power supply powering the circuit!
It gets even better. After the sim is stopped, if you then hold down Ctrl-Alt and click on one of the power dissipation plots' headings, it will average and integrate (optionally over an interval you selected; otherwise over the visible part of the plot), giving you the average power dissipation (and the total joules). I LOVE being able to get the average power dissipated by every component, and every SUBSYSTEM, and the entire circuit, so darn easily!
Another fantastic feature is that you can use _WAVE FILES_, for inputs and/or outputs! The possibilities are exquisitely intriguing, to say the very least!
By the way, this software is a FREE DOWNLOAD!! (from linear.com) And there are tens of thousands of free downloadable models for components and devices.
Tom
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okay, so ive built a new computer, and that accutally supports 5.1 without occupying the mic slot.
however, i still need the "mic box" for my ps3, since it doesnt have any similar feature.
before i used a usb mic (stereo mic built into my logitech webcam)
i still do though i got a mic that i can use for the sounds around me.
so well i have no idea of which chips to use, do you know any you can recommend?
however, i still need the "mic box" for my ps3, since it doesnt have any similar feature.
before i used a usb mic (stereo mic built into my logitech webcam)
i still do though i got a mic that i can use for the sounds around me.
so well i have no idea of which chips to use, do you know any you can recommend?
okay so ive searched around abit, and come up with this:
using this mic: Clear Speech Audio Pick-up Surveillance Microphone - Free Shipping - DealExtreme
it has a built in amp, and gets quite good compliments.
so, could i use a L165 opamp?
now the only thing that keeps me stuck, is how to find the appropriate values for the resistors. Also, is the buffing amps strictly needed? id kinda like the simplest design possible.
thanks for the help though
using this mic: Clear Speech Audio Pick-up Surveillance Microphone - Free Shipping - DealExtreme
it has a built in amp, and gets quite good compliments.
so, could i use a L165 opamp?
now the only thing that keeps me stuck, is how to find the appropriate values for the resistors. Also, is the buffing amps strictly needed? id kinda like the simplest design possible.
thanks for the help though
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