Sadly he did a little more than just link him to a search engine.... just more spoonfeeding.
In this case google will only work if you do the search for him, sift through the results and post him the data for him to ignore.
I tend to think it an obvious sign that the thread has gone to hell when the mods resort to such tactics as well. Nothing we say will change it. This much seems established.
Time to throw it away yet? It's an embarrassment.
If I can I love helping those who make a little effort, to research for themselves, to consider the advice of others, to put to use their new found knowledge.... all I see here is the polar opposite of all that makes for a healthy thread/exchange of ideas.
There's tolerant, and there's ridiculous, right now it's over 15 pages of the two, and he wants to concentrate on class d causing cancer ... or what... brainwashing the goldfish?
The more of this we get, the less worthwhile the forum as a whole will become. Please put a stop to it now.
Oh yeah, a 1000W amp in an acrylic case... also brilliant. What RPM will the cooling turbines run at.
It should also be obvious that no one with a serious intent to build, or learn something would be at all content with "letting it sit" until the savior happens along to give them some holy go ahead. C'mon...
:bs:
In this case google will only work if you do the search for him, sift through the results and post him the data for him to ignore.
I tend to think it an obvious sign that the thread has gone to hell when the mods resort to such tactics as well. Nothing we say will change it. This much seems established.
Time to throw it away yet? It's an embarrassment.
If I can I love helping those who make a little effort, to research for themselves, to consider the advice of others, to put to use their new found knowledge.... all I see here is the polar opposite of all that makes for a healthy thread/exchange of ideas.
There's tolerant, and there's ridiculous, right now it's over 15 pages of the two, and he wants to concentrate on class d causing cancer ... or what... brainwashing the goldfish?
The more of this we get, the less worthwhile the forum as a whole will become. Please put a stop to it now.
Oh yeah, a 1000W amp in an acrylic case... also brilliant. What RPM will the cooling turbines run at.
It should also be obvious that no one with a serious intent to build, or learn something would be at all content with "letting it sit" until the savior happens along to give them some holy go ahead. C'mon...
:bs:Hey, like I said, there are 1200 threads in the class D section.
If people just want to dump, do it else where.
If someone does have some experience with the audibility issues when working with low ultrasonics, it will be most appreciated.
Otherwise, just let this thread sit!!
If people just want to dump, do it else where.
If someone does have some experience with the audibility issues when working with low ultrasonics, it will be most appreciated.
Otherwise, just let this thread sit!!
Chill dude... everybody tries (and does) answer your questions. They parrot your behaviour... because, frankly, you wearing everybody a little thin. You are talking about 50 year old science. It has been realizeable (barely) for 25 years. It has been viable for 5 or 10 years.
You are talking to degreed engineers here... both de facto and DIY honorary... heavy hitters... there are gods here and they keep themselves hidden (I have a very special respect for the self taught here). You ignore, refute, and snub these people, albiet politely, when they point out some very questionable assumptions on your part.... to what end? This is not really science anymore; for the most part it is applied science... engineering. Now, engineers, at least the best ones, don't like discussing BS ad nauseum. Instead, they give answers and guiding theories and principles... you show very little respect for that, and some condescending 'tude to boot. Had you ever BUILT or DESIGNED anything; your 'tude would be different.
BOTTOM LINE
1) We can assume with reason that all critters that share an identical environment will likely have simlilar tolerations to sound. Our tolerance for sound evolved as a function of our environment... critters that shared an environment will likely share tolerance... in so far as their relative lifespans are concerned.
2) What we KNOW is that 100-105 dB is the "redline" beyond that, you are taking chances. You could apply that reasonably with terrestrial mammals give or take 10 dB (take for erring toward the good).
3) We know that 70-75 dB is a level we can tolerate for extended, if not completely indefinate periods of time.
4) Our knowledge beyond that is limited. In the case of humans, we work to avoid hearing loss... probably not a concern for you with a 1000 Watt sub in mind. As far as the OTHER critters are concerned, our knowledge is focused on what will drive ants from our property. The bulk of our meager efforts are going to preventing extinction and displacing habitat.
5) The fallacy here, and it is a BIG ONE, is that you need to make some elaborate consideration in regard to PWM freq. in order to proceed further. This is WRONG. Be it 22.5 kHz or 22.50001 kHz; your PWM freq. should be suppressed by 80 to 120 dB. Work the damn numbers... unless your target peak SPL is at 150 dB or more, the mosquitos will still be happy. Your filter gives you 2 poles... your speaker gives 1 or 2 at least. I have already told you, assuming the obvious is done right, that your coils will make more sound than the drivers... in one butt and out the other.
6) At your current rate, you will have a sub amp designed in 2046. You will have to pay $22,000 for a 2N3055.
7) If you are meditating on a bamboo mat right now, eating a bowl of tofu; send me your address. I will come, and get you fed, drunk and laid (by a woman)... maybe you can learn a new way.
🙂
You are talking to degreed engineers here... both de facto and DIY honorary... heavy hitters... there are gods here and they keep themselves hidden (I have a very special respect for the self taught here). You ignore, refute, and snub these people, albiet politely, when they point out some very questionable assumptions on your part.... to what end? This is not really science anymore; for the most part it is applied science... engineering. Now, engineers, at least the best ones, don't like discussing BS ad nauseum. Instead, they give answers and guiding theories and principles... you show very little respect for that, and some condescending 'tude to boot. Had you ever BUILT or DESIGNED anything; your 'tude would be different.
BOTTOM LINE
1) We can assume with reason that all critters that share an identical environment will likely have simlilar tolerations to sound. Our tolerance for sound evolved as a function of our environment... critters that shared an environment will likely share tolerance... in so far as their relative lifespans are concerned.
2) What we KNOW is that 100-105 dB is the "redline" beyond that, you are taking chances. You could apply that reasonably with terrestrial mammals give or take 10 dB (take for erring toward the good).
3) We know that 70-75 dB is a level we can tolerate for extended, if not completely indefinate periods of time.
4) Our knowledge beyond that is limited. In the case of humans, we work to avoid hearing loss... probably not a concern for you with a 1000 Watt sub in mind. As far as the OTHER critters are concerned, our knowledge is focused on what will drive ants from our property. The bulk of our meager efforts are going to preventing extinction and displacing habitat.
5) The fallacy here, and it is a BIG ONE, is that you need to make some elaborate consideration in regard to PWM freq. in order to proceed further. This is WRONG. Be it 22.5 kHz or 22.50001 kHz; your PWM freq. should be suppressed by 80 to 120 dB. Work the damn numbers... unless your target peak SPL is at 150 dB or more, the mosquitos will still be happy. Your filter gives you 2 poles... your speaker gives 1 or 2 at least. I have already told you, assuming the obvious is done right, that your coils will make more sound than the drivers... in one butt and out the other.
6) At your current rate, you will have a sub amp designed in 2046. You will have to pay $22,000 for a 2N3055.
7) If you are meditating on a bamboo mat right now, eating a bowl of tofu; send me your address. I will come, and get you fed, drunk and laid (by a woman)... maybe you can learn a new way.
🙂
1000 watts or more is for infra bass, below30hz, not for the kind of sound that could threaten hearing.
Becaue 23.5khz is different than 40khz or 100khz, I'm still looking for some published material that shows what levels are entirely imperceptible, not just tollerable.
I agree that three will be ultrasonic radiation from magnetics, and so they will need to be boxed up.
But even a huge sub woofer will radiate some also.
Anatech points out that this is residential, not industrial. It is actually supposed to be an ideal listening environement.
So lets let this thread sit, for as long as it takes. Lets not make it any longer than it already is.
Then maybe I, or maybe someone else will find some material that speaks of things people have made that subject people to low levels of low ultrasonic for extended time periods.
So please, let this thread go quiet, and this be the last post, until someone comes across such information.
Becaue 23.5khz is different than 40khz or 100khz, I'm still looking for some published material that shows what levels are entirely imperceptible, not just tollerable.
I agree that three will be ultrasonic radiation from magnetics, and so they will need to be boxed up.
But even a huge sub woofer will radiate some also.
Anatech points out that this is residential, not industrial. It is actually supposed to be an ideal listening environement.
So lets let this thread sit, for as long as it takes. Lets not make it any longer than it already is.
Then maybe I, or maybe someone else will find some material that speaks of things people have made that subject people to low levels of low ultrasonic for extended time periods.
So please, let this thread go quiet, and this be the last post, until someone comes across such information.
Is it a real limit? I say no. You can buy a set of MOSFETs (4 pcs) for $16 wich can put out 2000 W sinus (over 3000 W music) power full band with safety margins. Do you want more? Do you want cheaper?
MOSFETs can be cooled very well, there is no reason why you would have to reach even higher efficiency on semiconductors. You can achieve ~3% loss at 40 kHz switching freq, and with BD modulation this means 80 kHz effective freq and half amplitude, can be filtered out with a single 5 cm diameter iron powder core choke (+2cap). It's maybe easier to build, then find the freq limit. 🙂
The place of dominant pole isn't primary question. It can be even at 0 Hz. But with 1 kHz 5th order LPF at 400...500 Hz closed loop phase shift increases to 180 degrees, so at this point loop gain have to be much less then 0 dB. IMHO this doesn't "allow a very very high loop gain" at audio band. There are some method wich allows, but they are not trivial like "dominant pole".
But everybody have to make his own mistake. 🙂
Lets just talk about the environmental aspects of low ultrasonic, 23.5khz. That was and still is the reason for starting this thread.
I know I shouldn't be posting here but I just want to let something out. this is getting silly.
why do you want to do something in an unorthodox way? what do you really want to prove? that you know something we don't? or that something that we say should not be done that you can? we don't say you can't do it, it's just too impractical that too much effort is needed to do it right or just simply make it work.
if you want something at 1000W? why not just buy something commercial that do 1500W and get over it?
I know you want this topic to stay with the effects of ultrasonics but everything that has been said and posted is related to the main topic one way or another.
if the small resistance limits a semiconductor power dissipation, why not use something bigger or more of them and share the dissipation rather than do much more work to move the dissipated power to other parts of the amp? all electronic devices have a practical power limit. I cannot imagine how big the inductors you would need for such a device. it would need very thick wires to handle the high currents with low loss and also have to be physically bigger for the higher inductance needed for the lower frequency and you want them air cored which makes them even more bigger which equates to really big inductors then you want a several order filter then you would need a lot of those huge inductors. I know, you said that size wouldn't matter since they would be in the speaker box....yeah, but the components would take much of the air space in the box so you would need a bigger box to provide the right box volume for whatever sub you have planned for that.
ok, so you want to place the amp in plexi so it would look cool. then you mention you need to box up the magnetics to limit ultrasonic noise.....I wonder what would your amp then look like. a plexi box with smaller boxes inside? cool? it must be, for you.
there are a lot of sources of ultrasonic noise in a domestic environment. I don't see documented cases of rats or other animals getting cancer from the TV noise. (although that would be a nice side effect for pest control). in short, if you really want to work with 23.5kHz then do it and not bother others.
I doubt that you have worked with any high frequency circuits so you prefer to work with something with lower operating frequency. other members already confronted you and told you that you might have not made a SMPS or any high frequency device which I believe is true since you didn't react to their posts. if you have, do you have proof on that?
I say there are things in life that you must accept. these people that are helping you and telling comments that this will work and that will not because they have done that and found that themselves and if you don't listen to them, you're simply doing what they did wrong and making the same mistakes all over again which is just plain stupid and a waste of time and resources.
why do you want to do something in an unorthodox way? what do you really want to prove? that you know something we don't? or that something that we say should not be done that you can? we don't say you can't do it, it's just too impractical that too much effort is needed to do it right or just simply make it work.
if you want something at 1000W? why not just buy something commercial that do 1500W and get over it?
I know you want this topic to stay with the effects of ultrasonics but everything that has been said and posted is related to the main topic one way or another.
if the small resistance limits a semiconductor power dissipation, why not use something bigger or more of them and share the dissipation rather than do much more work to move the dissipated power to other parts of the amp? all electronic devices have a practical power limit. I cannot imagine how big the inductors you would need for such a device. it would need very thick wires to handle the high currents with low loss and also have to be physically bigger for the higher inductance needed for the lower frequency and you want them air cored which makes them even more bigger which equates to really big inductors then you want a several order filter then you would need a lot of those huge inductors. I know, you said that size wouldn't matter since they would be in the speaker box....yeah, but the components would take much of the air space in the box so you would need a bigger box to provide the right box volume for whatever sub you have planned for that.
ok, so you want to place the amp in plexi so it would look cool. then you mention you need to box up the magnetics to limit ultrasonic noise.....I wonder what would your amp then look like. a plexi box with smaller boxes inside? cool? it must be, for you.
there are a lot of sources of ultrasonic noise in a domestic environment. I don't see documented cases of rats or other animals getting cancer from the TV noise. (although that would be a nice side effect for pest control). in short, if you really want to work with 23.5kHz then do it and not bother others.
I doubt that you have worked with any high frequency circuits so you prefer to work with something with lower operating frequency. other members already confronted you and told you that you might have not made a SMPS or any high frequency device which I believe is true since you didn't react to their posts. if you have, do you have proof on that?
I say there are things in life that you must accept. these people that are helping you and telling comments that this will work and that will not because they have done that and found that themselves and if you don't listen to them, you're simply doing what they did wrong and making the same mistakes all over again which is just plain stupid and a waste of time and resources.
Ah, this is just the environmental effect of too many warning labels screwing with natural selection.
Hi zenmasterbrian,
If I may point something out. It appears that there is very little information that is easily accessible to you on this topic. Therefore, your research is groundbreaking.
I would suggest that you should therefore build and test your amplifier. There are times an empirical experiment can save an awful lot of research time and put to bed any questions that remain. In my time on this earth I find I learn far more by doing. I believe you are at the stage where you should build your amplifier. Do not wait for any opinions for or against or you will never accomplish your goals.
-Chris
If I may point something out. It appears that there is very little information that is easily accessible to you on this topic. Therefore, your research is groundbreaking.
I would suggest that you should therefore build and test your amplifier. There are times an empirical experiment can save an awful lot of research time and put to bed any questions that remain. In my time on this earth I find I learn far more by doing. I believe you are at the stage where you should build your amplifier. Do not wait for any opinions for or against or you will never accomplish your goals.
-Chris
anatech,
I'm trying to let this thread cool down, instead of continuing to lengthen with meta.
But I have to respond to you.
No one needs to post here, if they are hostile to the topic. There are 1200 other topics in this thread.
Maybe there in some information available, maybe there is not. But continuing dumping is confusing those who might have it.
Eventually, I or others will find what information is available. SMPS and inverters still sometimes operate in the 20khz to 25khz range. There are other types of ultrasonic appliances too. So there is some body of knowledge about what the boundary lines are.
So let this thread sit, and eventually one of us will come up with something topical.
I'm trying to let this thread cool down, instead of continuing to lengthen with meta.
But I have to respond to you.
No one needs to post here, if they are hostile to the topic. There are 1200 other topics in this thread.
Maybe there in some information available, maybe there is not. But continuing dumping is confusing those who might have it.
Eventually, I or others will find what information is available. SMPS and inverters still sometimes operate in the 20khz to 25khz range. There are other types of ultrasonic appliances too. So there is some body of knowledge about what the boundary lines are.
So let this thread sit, and eventually one of us will come up with something topical.
Hey !,
I just recommended you attempt to build it. Just like Nelson Pass or any other innovator. Once the thing exists, all the arguments and postulating is over.
Trying to be helpful. You seem to be capable of building this. You have the construction details figured out it seems. What is now stopping you?
-Chris
I just recommended you attempt to build it. Just like Nelson Pass or any other innovator. Once the thing exists, all the arguments and postulating is over.
Trying to be helpful. You seem to be capable of building this. You have the construction details figured out it seems. What is now stopping you?
-Chris
I guess it is prudence.
But look, there are all kinds of ways to introduce meta into this thread. None of it is productive.
Lets just let it sit.
Eventually one of us will come up with some information about the design guidelines that should be followed when people could be exposed to low level 20khz to 25khz on a continual basis.
I remain confident that this will emerge, if we can just let this thread sit.
But look, there are all kinds of ways to introduce meta into this thread. None of it is productive.
Lets just let it sit.
Eventually one of us will come up with some information about the design guidelines that should be followed when people could be exposed to low level 20khz to 25khz on a continual basis.
I remain confident that this will emerge, if we can just let this thread sit.
Sorry for posting again, but I can't resist.
Yes there are, and you are the main contributor, so I would kindly ask you to stop posting in your own thread for the sake of everyone.
If you let it sit no one will post anything else, and nothing will emerge. Thus, I agree with you. Everyone, please let this thread sink into oblivion.
zenmasterbrian said:
Yes there are, and you are the main contributor, so I would kindly ask you to stop posting in your own thread for the sake of everyone.
zenmasterbrian said:
If you let it sit no one will post anything else, and nothing will emerge. Thus, I agree with you. Everyone, please let this thread sink into oblivion.
Sorry to be off topic here...
Any of you guys watched the documentaries where people, for whatever aweful reason, have half their brain removed? They can say chicken, and they understand what a chicken is, but, they can't identify a picture of a chicken.
hmm...
🙂
Any of you guys watched the documentaries where people, for whatever aweful reason, have half their brain removed? They can say chicken, and they understand what a chicken is, but, they can't identify a picture of a chicken.
hmm...
🙂
Since this thread is approaching riduculous, I might as well post something to think about. Z, you should think about how much inductance you would need to provide a reasonable ripple free speaker current with a PWM frequency in the range of 1 KHz or whatever. I don't know too much about woofers, but I suspect the ripple will be audible or else the low frequency stuff will be poor quality.
Who really care about dogs? Have you ever seen any dogs get upset listening to a class D amp?
If you want some help with your issue, I suggest you restate the question, in very specific terms.
Who really care about dogs? Have you ever seen any dogs get upset listening to a class D amp?
If you want some help with your issue, I suggest you restate the question, in very specific terms.
Proposed switching frequency would be 23.5khz.
Proposed filter corner frequency would be 1khz.
So there would not be significant "ripple" of the 23.5khz variety in what goes to the woofer. But perhaps it is not zero either.
So I need to know, is a small amount of 23.5khz acceptable. How little? Is it different at 25khz?
Lot of people are dumping on this thread. They should not be posting here, period.
As far as how big the filter inductor would be? They would be just like the ones used in a 1khz passive speaker crossover.
There is one big difference in the result. Since these inductors are inside the feedback loop, their full resistance does not add on to the amps output resistance.
For all future posts on this thread, there is only one narrow topic, if you are not prepared to speak to this alone, do not post here.
Topic:
What are the accepted limits for environmental exposure to ultrasonics of the 20khz to 30khz range?
Proposed filter corner frequency would be 1khz.
So there would not be significant "ripple" of the 23.5khz variety in what goes to the woofer. But perhaps it is not zero either.
So I need to know, is a small amount of 23.5khz acceptable. How little? Is it different at 25khz?
Lot of people are dumping on this thread. They should not be posting here, period.
As far as how big the filter inductor would be? They would be just like the ones used in a 1khz passive speaker crossover.
There is one big difference in the result. Since these inductors are inside the feedback loop, their full resistance does not add on to the amps output resistance.
For all future posts on this thread, there is only one narrow topic, if you are not prepared to speak to this alone, do not post here.
Topic:
What are the accepted limits for environmental exposure to ultrasonics of the 20khz to 30khz range?
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