Hi poobah,
That's so funny. Even a poobah can drive space ship safely. I am affraid if I googling as your request, then shown one name, the only, you know who? 😀
Mjjz, use that hat only when you passing near Brian's home, not every time, because you may looked fool
with that hat. 😀
That's so funny. Even a poobah can drive space ship safely. I am affraid if I googling as your request, then shown one name, the only, you know who? 😀
Mjjz, use that hat only when you passing near Brian's home, not every time, because you may looked fool
with that hat. 😀mzzj, poohbah
It nothing personal. But I am asking you not to post on this thread.
It discourages people who might want to contribute to the discussion.
So, I ask you not to post here.
It nothing personal. But I am asking you not to post on this thread.
It discourages people who might want to contribute to the discussion.
So, I ask you not to post here.
Does EMI from class d cause cancer?
Should the amp manufacturers have to pay some cancer research tax based on the level of EMI their products generate?
Does fixed frequency switching generate more localized cancer?
Does a BJT cause less cancer than a mosfet?
Since D amps cause cancer, can shielded speakers save us from cancer? Would you need less shielding with an 8 order filter, but more if you used a mosfet? Isn't the body diode to blame?
This seems to confirm parasites cause cancer after all.
Should the amp manufacturers have to pay some cancer research tax based on the level of EMI their products generate?
Does fixed frequency switching generate more localized cancer?
Does a BJT cause less cancer than a mosfet?
Since D amps cause cancer, can shielded speakers save us from cancer? Would you need less shielding with an 8 order filter, but more if you used a mosfet? Isn't the body diode to blame?
This seems to confirm parasites cause cancer after all.
zenmasterbrian said:
that is what people have been trying to do from the start of this thread and all you did was ignore them.
i know, I know....... "djQUAN, I am asking you not to post in this thread blah blah blah....." from what I've been reading, it's too hard not to reply.
I also give my meta-vote.*sits in the corner and watches*
Guess it hurts less kicking a dead horse if we all take turns 🙂
"djQuan, I am asking you not to post on this thread."
Guess we dont' listen very well ourselves. Maybe you should lead by example.
"djQuan, I am asking you not to post on this thread."
Guess we dont' listen very well ourselves. Maybe you should lead by example.
poobah said:
I refuse to respond to such a meta post. When you can tt tt tt tt tt TTTTTOPical, I will repeat the previously answeredX10 question.
If you'd just pay attention to it this time, you'll find the answer already within.
I don't want to have to not reply again, which you're not forcing me to do..metally.. anyway.
Now then, back to the topical topic..topically.
Since we received complaints about this thread I close it ( temporarily ).
Zenmaster,
It isn't possible for you to control this thread absolutely - that isn't how DIY Audio works. I think some members are frustrated because they feel that you aren't even considering points which they have made some effort to write in an effort to point out. Also that you ask some questions which you could easily answer using the search functions here and a general search engine such as Google.
Some Others:
On the other hand, you members which have found it frustrating to try to help Zenmaster with his problem(s) should do as I always suggest, just walk away and let him see if anyone else wishes to discuss things with him on his level.
Let's start out again, and no head-butting or eye gouging! 😉
I would hate for this thread to get to an acrimonious level that would require closure.
Variac, thank you for reopenning this.
I have never sought to control this thread absolutely. But I would hope that it stays somewhat topical.
I discussed with people what they said, but beyond a point, they were just throwing mud.
I know that some people may not go along with the line of investigation into class D that I want to pursue. But that does not make it right for them to start throwing mud, or to try to get this thread close down.
I can spend more time looking for outside information. But that is irrelevant if people are just going to introduce off topic argumentation.
As I see it, people can voice alternate views, and I can and did discuss them. But if they just want to throw mud and try to prevent this from continuing, I don't think they should be posting here.
I have never sought to control this thread absolutely. But I would hope that it stays somewhat topical.
I discussed with people what they said, but beyond a point, they were just throwing mud.
I know that some people may not go along with the line of investigation into class D that I want to pursue. But that does not make it right for them to start throwing mud, or to try to get this thread close down.
I can spend more time looking for outside information. But that is irrelevant if people are just going to introduce off topic argumentation.
As I see it, people can voice alternate views, and I can and did discuss them. But if they just want to throw mud and try to prevent this from continuing, I don't think they should be posting here.
I want to explore the possibility of designing a class D subwoofer amp at the lowest practical switching frequency.
This amp would never be used for audio signals at a frequency never greater than 300hz.
Now since some of the switching signal still could bleed through to the driver, it probably still needs to be ultra sonic.
So the question is, how low can it be, and still not be audible or perceptible in any way, even with constant exposure.
Also, what about effects on animals.
I had settled on a tentative number of 23.5khz minimum.
Actually it would be a range of 23.5khz to 25.5khz. More about this later.
Now, there are a couple dozen interrelated design issues here, but I right now only want to look at this one.
How low a frequency of ultra sonic can be put out continually, at low level, without it being any kind of physiological or environmental hazard?
I believe there is precedent here in switching amps and power supplies from the 1970s, running in this range.
The switching amps probably being like this one, for LF audio only.
This amp would never be used for audio signals at a frequency never greater than 300hz.
Now since some of the switching signal still could bleed through to the driver, it probably still needs to be ultra sonic.
So the question is, how low can it be, and still not be audible or perceptible in any way, even with constant exposure.
Also, what about effects on animals.
I had settled on a tentative number of 23.5khz minimum.
Actually it would be a range of 23.5khz to 25.5khz. More about this later.
Now, there are a couple dozen interrelated design issues here, but I right now only want to look at this one.
How low a frequency of ultra sonic can be put out continually, at low level, without it being any kind of physiological or environmental hazard?
I believe there is precedent here in switching amps and power supplies from the 1970s, running in this range.
The switching amps probably being like this one, for LF audio only.
Is this really a good forum to be finding this this information?
I think you should be asking medical professionals or searching the web for this information. Someone here already posted the findings from Google that dogs and cats hear into the 30k-40k range. Maybe you should build your circuit and see if the dogs howl or the cat runs away.
I found these on Google- there's such a wealth of information out there:
http://www.google.com/search?q=emf+humans&hl=en&lr=&start=0&sa=N
http://www.who.int/topics/electromagnetic_fields/en/index.html
http://infoventures.com/emf/top/others-i.html
When you've settled on a frequency, I'm sure technical aspects can be worked out here- you're going to need some pretty nifty active base drive circuits to switch those BJT's....
Simple question: What voltage level of the 23.5kHz signal do you expect the subwoofer to receive?
Then: Does a subwoofer have much of any response at 23.5kHz?
Answer these and you have your answer. The design may have some caps. signing the same 23.5kHz song but since it is in a box (which don't radiate this high frequency well at all) there should not be any problem. Unless you have some sort of transducer else where in the circuit to convert this voltage into sound waves. It's not like animals can hear EMI. I never hear that 1kHz signal running on my bench into a resistive load not matter what level I set it too.
Don't post back to me unless you answer these questions. I originally jumped out on page 3 because of how you 'learn'. Only trying to help some now. If you can't figure out the answers above then you don't know enough to even begin to design such an amplifier.
-SL
Then: Does a subwoofer have much of any response at 23.5kHz?
Answer these and you have your answer. The design may have some caps. signing the same 23.5kHz song but since it is in a box (which don't radiate this high frequency well at all) there should not be any problem. Unless you have some sort of transducer else where in the circuit to convert this voltage into sound waves. It's not like animals can hear EMI. I never hear that 1kHz signal running on my bench into a resistive load not matter what level I set it too.
Don't post back to me unless you answer these questions. I originally jumped out on page 3 because of how you 'learn'. Only trying to help some now. If you can't figure out the answers above then you don't know enough to even begin to design such an amplifier.
-SL
Man! I guarantee that your subwoofer will not harm to animals. Why? Because you make subwoofer that does not produce high level audio. Why? The high level audio cutted already. How? By filter and naturally your woofer driver. Is that clear for you? So, what frequency is not a matter and not important to know.
Are you read table from me?
Now start with designing the circuit. Somebody boring with same question.
Are you read table from me?
Now start with designing the circuit. Somebody boring with same question.
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