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@ Steven, I would go more with option/situation "b", noisy regulator. I don't think it is the speaker. I don't bet this time cos you always win
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João
Steven, may I add a comment?s_mack wrote:a) I didn't use a high enough quality speaker;
I know, right? That's why I called it a "career path" and not "gambling addition" like the judge said.jhsa wrote:@ Steven, I would go more with option/situation "b", noisy regulator. I don't think it is the speaker. I don't bet this time cos you always win
As I've said before, I know very little about audio. But consider this: I had a c**p pair of PC speakers plugged into my computer and they would constantly make noise. I finally bought a more expensive set and now there's nothing. The computer stayed the same, the speakers changed. Both sets were unpowered basic speakers (not the ones with fancy surround sound and woofers). So... if not the speaker, then the cable? The soldered joint? I really have no idea. Two things are preventing me from diagnosing it: #1) mine doesn't hiss; #2) my [lack of] knowledge on the subject. That's why I issued the "bounty" and also why I'm not shying away from this. I completely believe that people are bothered by it and I want it resolved. I just don't know how yet.andrewju wrote:Steven, may I add a comment?s_mack wrote:a) I didn't use a high enough quality speaker;
I do not fully agree with your statement. I mean, I don't understand how a bad speaker could cause the "hiss" noise. A speaker converts an electric signal into sound. A bad quality speaker may do the conversion wrongly, which will result in bad sound quality, or even no sound at all. But it cannot "invent" a sound in the absence of the signal.
If a speaker makes a noise, it means something (some kind of an electric signal) is coming to it. By going for a higher quality speaker, you will likely just end up with a higher quality hiss...
Just thinking out loud...
They will always be leaning to some degree. It is not possible to get them perfectly straight, nor do they need to be. They really don't even have to be all that close to do their job. I can't imagine they are causing this problem, but I guess I can't say I know for sure until I know for suregb21914 wrote:confirm that the pins are straight up and down, or whether they are "leaning" at all?
I don't disagree with you. I'm just trying to come up with some logic that may determine the source of the noise. As I've said before...I'm pretty sure I can live with what I have. It's just "hissy"s_mack wrote:They will always be leaning to some degree. It is not possible to get them perfectly straight, nor do they need to be. They really don't even have to be all that close to do their job. I can't imagine they are causing this problem, but I guess I can't say I know for sure until I know for suregb21914 wrote:confirm that the pins are straight up and down, or whether they are "leaning" at all?
I'd say in this case it could have been some interference (electromagnetic radiation) that was caught by the old speakers - probably due to poor cable quality.s_mack wrote:But consider this: I had a c**p pair of PC speakers plugged into my computer and they would constantly make noise. I finally bought a more expensive set and now there's nothing.
Man, sometimes you make the plainly obvious easier to seejhsa wrote:is it possible to turn the 9x mainboard off while still running the 9xtreme? It looks like the 9x itself is one of the factors that isn't common to all radios. So, could some 9x radios induce the noise while others don't??
Ahhh, right... Then locating the root cause is not that easy.MikeB wrote:Looking at the speaker signal itself probably won't help as we have a class 'D' amplifier that outputs PWM, which may, of course, be part of the problem. Maybe the PWM frequency is slightly different and causes the problem.
I'm tempted to buy a Taranis, nothing to do with this but all to do with an irrational desire to try SBUS (and I'm maxing out 8 channels) and no point buying a replacement for my DJT given the price delta.s_mack wrote:The backlight is LED, which runs on DC. So no inverter.
It most likely comes down to either a) I didn't use a high enough quality speaker; b) the switching regulators are producing too much noise; c) I didn't get the ground path right (since i have zero experience with audio, I wouldn't be surprised); or d) we're using single-sided input instead of differential, which is recommended in the datasheet to reduce noise. Or some combination of the above.
The variance in how much it bothers me suggests it could be 'a'. Or it just comes down to peoples' ears and their differences. That video... mine doesn't sound like that at all, but is that a difference between his and mine? Or is the camera picking up the audio differently than if I heard it in person?
This is tricky.
duststorm wrote:I noticed that the hissing changed if I changed the external transmitter PPM from 300usec to some other value. On some settings the hissing even stopped completely.
Perhaps this can help to find the source?
We may be looking at two issues then.duststorm wrote:I noticed that the hissing changed if I changed the external transmitter PPM from 300usec to some other value. On some settings the hissing even stopped completely.
Perhaps this can help to find the source?