speaker hiss

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gb21914
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Re: speaker hiss

Post by gb21914 » Thu Nov 12, 2015 2:22 am

Wives that dont seem to understand RC stuff...seems common :)
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Re: speaker hiss

Post by ShowMaster » Fri Nov 13, 2015 4:00 pm

The sounds are definitely not what I hear. Yes to getting a few of these boards in Mikes hands and maybe a few tech types that can converse on what's going on.
I'm willing if anyone's in the LA area or can arrange an exchange.

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Re: speaker hiss

Post by jhsa » Fri Nov 13, 2015 4:27 pm

Mine has this high pitch noise. But at very low volume. It doesn't really bother me and for me it is important to have a clear noiseless sound..

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Re: speaker hiss

Post by ShowMaster » Fri Nov 13, 2015 4:51 pm

Finding and fixing the loud clicking and buzzing is my first concern. The higher pitched background noise isn't heard at my field above the gas and turbines flying. Find that first and then go after the lesser sounds. My Taranis is about the same level in a quiet place as my 9xt is now. Having older ears helps there. Something positive I guess for too many birthdays.
I'm on my way now to a work on a tv show with 110-120db sound going on. Ear plugs all day!

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Re: speaker hiss

Post by tedbmoss » Sat Nov 14, 2015 4:48 am

Reformat the SD card. :idea:


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Re: speaker hiss

Post by ShowMaster » Sat Nov 14, 2015 6:38 am

Couldn't hurt.

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Re: speaker hiss

Post by gb21914 » Sun Nov 15, 2015 3:21 am

tedbmoss wrote:Reformat the SD card. :idea:
except that it's already been done at least 3 times :)
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Re: speaker hiss

Post by MikeB » Sun Nov 15, 2015 8:08 pm

Catching up with things to do!
On the test versions post, I've just posted a specific test version to try to work out the cause of the loud buzz when audio files are playing.
I had previously had an audio tone file played with two different sample rates and bitsper sample. That indicated accesses to the SD card (on that radio) were causing the noise. This test version does some specific tests on the SD card signals.
From the main screen, press UP LONG, then RIGHT a few times until you get to a DEBUG screen. This lists Audio Test, and you may choose test 0, 1 or 2. The test is started by pressing MENU. To stop a test, press EXIT.
Please try all three tests in turn and let me know which, if any, cause any clicking/buzzing on the audio.

Interestingly, I have a very low level clicking on my speaker, but when pressing EXIT from these tests, it stops for a moment. This gives me something to experiment with.

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Re: speaker hiss

Post by ShowMaster » Sun Nov 15, 2015 9:27 pm

So many threads going on Mike. Could you please post the links to any new upgrades or test Fw's just to be sure.
I have these saved so far

viewtopic.php?f=95&t=7182

viewtopic.php?f=7&t=4676#p65894


viewtopic.php?f=126&t=7751

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Re: speaker hiss

Post by MikeB » Sun Nov 15, 2015 9:42 pm

Oops, I'd forgotten I'd added the thread from the last link you reference!
Normally I post the test versions on the post of the middle link, which is where this test version is.

I'll try to be more careful and specific in future!

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Re: speaker hiss

Post by jhsa » Sun Nov 15, 2015 10:05 pm

Mike, this test version applies to me as well, or is it only for the ones that have severe audio problems??
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Re: speaker hiss

Post by MikeB » Sun Nov 15, 2015 10:28 pm

Those with severe audio problems, particularly if there is a buzz/clicking when a voice file is playing that stops when the voice file plays.
You may try it. When I ran the tests, I couldn't hear anything different.

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Re: speaker hiss

Post by gb21914 » Mon Nov 16, 2015 1:38 am

I'll take a video in the am so you can see / hear for yourself, but I upgraded the firmware and ran the tests...there's no change in the clicking at all (from what I can hear).
Last edited by gb21914 on Wed Nov 18, 2015 3:12 am, edited 1 time in total.
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Re: speaker hiss

Post by ShowMaster » Mon Nov 16, 2015 6:37 am

Just because it was discussed, I swapped out the speaker with a larger 8 ohm like the one I used in my Taranis update. It didn't help with the faint high freq buzz. I didn't think that it would, but it was on my list.

For Mike,
I'm trying to scope the amp circuit but haven't figured out how to scope the output. It doesn't reference to ground. I have a dual trace scope so maybe both probes on the speaker leads, invert one channel?

I probed the input to the amp but didn't see anything I could reference to the data buzz I hear.
Not having the loud choppy audio and just the faint buzz is what I'm dealing with. The audio circuit below the amp is prone to picking up my cfl lamp buzz if I put my finger on the trace. That area may be prone to some RFI if a high a rf power module is used. No issue I cold tell with the xjt I'm using however.

The Taranis can be sensitive to the antenna bent left or right coupling RF into its audio I find.

I'll load in your test tone fw next.
Busy week next week, not home until late so I may not get Rc time until the weekend again.

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Re: speaker hiss

Post by stewwy » Mon Nov 16, 2015 10:14 pm

probable a bit of a simple answer to the problem, why not a simple cut off filter, it'll get rid of the hiss

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Re: speaker hiss

Post by ProZak » Tue Nov 17, 2015 2:33 am

stewwy wrote:probable a bit of a simple answer to the problem, why not a simple cut off filter, it'll get rid of the hiss
From what I gather in this thread, and my observations of my own installation, there is more than just "hiss". I have faint clocking/data "buzz" as well as what I'd call minor hiss (old ears though, so I accept that "hiss" may be more apparent to the younger gen. :lol: ).

"Hiss" would be caused by wide audio frequency response as you suggest (add a capacitor across the output somewhere) but the associated clocking/data "buzz" also suggests to me there's a circuit and/or layout coupling/bypass issue that needs to be addressed somewhere. I have the feeling that just removing "hiss" would only make "buzz" (and/or other somesuch) the subject of discussion instead. :|

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Re: speaker hiss

Post by MikeB » Tue Nov 17, 2015 4:29 pm

I've just posted a test version that doesn't use the I2C interface. On my Tx, this stops the 'buzz' I can hear.
I recorded the sound I could hear in Audacity so I could see the buzz was at 20Hz. This gave me the hint as to the possible source of it.

Looking at the tracking, I think the I2C signals and the audio signal run a long way close to each other.

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Re: speaker hiss

Post by jhsa » Tue Nov 17, 2015 4:41 pm

options? ;)
Mine doesn't bother me.. :)
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Re: speaker hiss

Post by MikeB » Tue Nov 17, 2015 5:34 pm

For more permanent use I've added a hardware option, for the 9Xtreme, to enable/disable the I2C interface usage.

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Re: speaker hiss

Post by s_mack » Tue Nov 17, 2015 6:11 pm

MikeB wrote:Looking at the tracking, I think the I2C signals and the audio signal run a long way close to each other.
Yes, they sure do!

I've attached a few images. One shows the problem, with the audio signal track running a LONG way sandwiched between the two I2C data lines (is that not an example of the theoretical worst thing I could have done in this situation?). The others showing a possible hacker's solution, if they want to rectify the situation and still retain use of their I2C. Caution: we're talking about very small components so a steady hand, good magnification, and an understanding how to remove surface mount chips is required.

The idea is to remove the indicated chips (10k resistor and 0.1uF capacitor) shown, then solder wires, preferably shielded, to the tiny pads and re-make the connection. You'll have to get a new resistor and capacitor and wire them in-line to recreate the circuit.

Not something I'm recommending. Just the best solution I can think of right now.

Obviously I'll adjust the design for future batches now that I'm aware of the problem. In the prototype, the tracks were almost the same, but the audio was on the outside rather than running in between.
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Re: speaker hiss

Post by jhsa » Tue Nov 17, 2015 6:17 pm

I just tried your version that disables the I2C. In fact that eliminates the helicopter sound I have reported earlier.. But the volume is so low that it doesn't bother me at all. The high pitch noise is worse in my opinion. This one starts when the radio clears the splash screen and enters normal operation. Again, it is also very low..

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Re: speaker hiss

Post by jhsa » Tue Nov 17, 2015 6:27 pm

s_mack wrote:
The idea is to remove the indicated chips (10k resistor and 0.1uF capacitor) shown, then solder wires, preferably shielded, to the tiny pads and re-make the connection. You'll have to get a new resistor and capacitor and wire them in-line to recreate the circuit.
What about not removing the resistor and capacitor (I presume they are in series), cut the traces eliminating that track, and solder a very thin wire between the resistor and the capacitor? It could also be a shielded audio cable from an old earphone, with the shield soldered to ground somewhere..

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Re: speaker hiss

Post by s_mack » Tue Nov 17, 2015 6:33 pm

jhsa wrote:
s_mack wrote:
The idea is to remove the indicated chips (10k resistor and 0.1uF capacitor) shown, then solder wires, preferably shielded, to the tiny pads and re-make the connection. You'll have to get a new resistor and capacitor and wire them in-line to recreate the circuit.
What about not removing the resistor and capacitor (I presume they are in series), cut the traces eliminating that track, and solder a very thin wire between the resistor and the capacitor? It could also be a shielded audio cable from an old earphone, with the shield soldered to ground somewhere..

João
Dealer's choice... but cutting those traces is more difficult, in my opinion.

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Re: speaker hiss

Post by MikeB » Tue Nov 17, 2015 6:34 pm

Most are only reporting very low noise levels. I feel the few with high noise levels have some other problem as well.

I'm attempting to locate the source of other noise.

Mike.

Edit: The next significant noise is at 500Hz (every 2mS). This is the rate at which the main loop runs. I dropped this rate to 250Hz and the noise reduced in frequency to 250Hz. I'll now need to look for a hardware signal the main loop drives at this rate.
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Re: speaker hiss

Post by LTMNO » Thu Nov 19, 2015 12:57 am

This is like reading a Sherlock Holmes novel, I can't wait to see what happens in the next chapter. ;-)
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Re: speaker hiss

Post by gb21914 » Mon Nov 23, 2015 6:02 pm

So I've been playing around with my transmitter, setting up telemetry and I'm not sure if I've stumbled across something or not.

I have the FRSKY D8R Plus II receiver in my bird, and have channel A1 setup as an internal voltage monitor. This seems to work fine, and I get a solid 5.0V across the telemetry screen. I also get my channel TSSI and RSSI...all good.

BUT

I noticed that my A2 channel has values...which at first glance is good...except that my voltage reader is not connected. I literally have nothing connected to A2...and yet the channel is "cross populating" data somehow?

This is unexpected behaviour? Could this also be contributing to the hiss or "helicopter"?
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Re: speaker hiss

Post by MikeB » Mon Nov 23, 2015 6:09 pm

The receiver is always reading the two analog inputs and sending them to the Tx, whether you have anything connected to them or not. If the A2 input is not connected, it is likely to read a similar physical voltage (0-3.3V) as A1. This is then sent to the Tx. Depending on your setting for A2 ratio in the Telemetry menu, you will then get a value displayed. If you have nothing connected to A2, then set the A2 ratio to 0.

This is quite normal and expected.

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Re: speaker hiss

Post by gb21914 » Mon Nov 23, 2015 6:13 pm

okay...the mystery continues :)
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Re: speaker hiss

Post by MikeB » Mon Nov 23, 2015 7:09 pm

Have you tested either of the test versions posted here: viewtopic.php?f=126&t=7751#p103194, that disable the I2C interface?
I don't think I've seen a report from you having done so.

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Re: speaker hiss

Post by gb21914 » Mon Nov 23, 2015 7:52 pm

gb21914 wrote:I'll take a video in the am so you can see / hear for yourself, but I upgraded the firmware and ran the tests...there's no change in the clicking at all (from what I can hear).
Yup, one of the first to do it. No noticeable changes for me. I used the first test version (the version posted below).

ersky9x9XT_romXenc.zip
17-Nov-2015 16:28
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