High-Pitched sound in recordings and speakers with a Zoom-R16 when connected USB-Ethernet

[Hugh Robjohns]

ooh! Now that looks promising. £40 in the UK. Might try and look into that to see if it meets its claims.

[robertkjr3d]

a dPDB DI box came in the mail today. I tested... Clean-Sound. No popping and clicking.

However, when I said 'a dpdb box', I meant just one. But I need 2 1/2 of them. Well two 'dual-boxes' and one single, for all 5-channels. The sixth channel is the sub.

i was not able to test connecting via USB as of yet. I need to rip out the panel-box from off my wall.

The dPDB box is much heavier than I expected, and a little bigger. Man, those are going to take up some space.

I experimented with the different levels on the dPDB 0, -20db, -40db.... i realize it could depend on the volume the receiver is set on. But in testing, I ended up selecting '0db', to get the lights on the 'R16' to even hit 3-bars. The specifications in the pamphlet claims I should select -40db for speaker-levels. But I wonder if that is for more concert levels, or something. In this case I hadn't switched all the channels off, because I only had one box. So the 'center, sub, rear-left & rear-right' were still running. And my wife was sleeping in the next room. So I couldn't not crank the volume super-loud.

[Hugh Robjohns]

a dPDB DI box came in the mail today. I tested... Clean-Sound. No popping and clicking.

The dPDB box is much heavier than I expected, and a little bigger. Man, those are going to take up some space.

The dimensions are all on the company website...

I experimented with the different levels on the dPDB 0, -20db, -40db.... i realize it could depend on the volume the receiver is set on.

Yes, obviously. Always best to start at the -40dB position, and then reduce if necessary... but it is designed to handle the output of a fully driven hefty stage amp, so it will be more than capable of handling your home receiver.

[robertkjr3d]

I finally got all the equipment. And I got everything all re-wired up with the latest design that included the DI-Boxes.
Keep in mind, the image is not showing all the paths, its just giving the basic idea. I was able to run a couple of tests after it was fastened to the wall again.

Recording to SD-Card is good... Comparing to my Bluray recordings as I speak. (well the source, usually doesn't match bluray quality anyway...)
I turn off the 'room-correction' and some processing before making recordings, but will keep fiddling with other settings

However, as Sam Spoons and Hugh... suggested that I have two problems. When trying to record using USB. I first could see noise in the 'Sub-Channel'. Why the sub-channel? The sub-channel does not go through a DI-Box with any ground-lift. With the sub, since quality is not as big of a concern. I stuck a cheap ole ground loop isolator on it that I mentioned I tried earlier with the rest of the channels. So the sub-channel-noise went away. But...
Next USB problem. So when recording... It still popped and clicked. So I believe I need to buy the IFFI product mentioned earlier. (there are 3 kinds... ) Likely, the kind that I can power the 'R16' locally, not by the computer. That is when using power-over-USB, it should power from a local source, not way down the extension line.

In the mean-time, I can start to play with recording and editing and different settings.... recording to the SD-Card. Someone pointed out... i can at least up the quality to 24-bit on the r16.

[Hugh Robjohns]

Two thoughts:

1. A cheap line-isolator transformer is likely to saturate and distort with high levels of low frequency signals.... so it may not provide good quality for your LFE/sub channel. Something to bear in mind.

2. The clicks you're experiencing appear to be related to using your R16 as a USB interface. Its very unlikely to be related to ground loops. Instead I would be looking at things like buffer sizes, and background activities in the computer (wifi activity, etc).

[robertkjr3d]

Two thoughts:

1. A cheap line-isolator transformer is likely to saturate and distort with high levels of low frequency signals.... so it may not provide good quality for your LFE/sub channel. Something to bear in mind.

2. The clicks you're experiencing appear to be related to using your R16 as a USB interface. Its very unlikely to be related to ground loops. Instead I would be looking at things like buffer sizes, and background activities in the computer (wifi activity, etc).

1)... acknoledged.. but its just the sub-channel lower than 60-100K... boom boom.. floor moving stuff. I'm much more likely to hear artifacts in the mid-ranges and the tweeters.
2) hmm.. but we've already seen this feed-back as actually registered sound. And I can see it show up in the registered spectral graph on both ends. Somehow its feeding back on the line, back to the zoom as has been suggested before. Your suggestion here is new.

[robertkjr3d]

2. The clicks you're experiencing appear to be related to using your R16 as a USB interface. Its very unlikely to be related to ground loops. Instead I would be looking at things like buffer sizes, and background activities in the computer (wifi activity, etc).

More on the #2... Even before recording. As mentioned I can see the noise on the device before going back to the computer to hit record. That is why I put a 'ground-loop-isolator' on the sub-channel to stop the noise. It is not buffering, there is nothing to buffer yet.

[Hugh Robjohns]

I am confused.

I was under the impression that recordings made on the R16 now were 'good' which I took to mean click- and whistle-free.

That being the case, the clicks must surely be an artefact of the audio data transfer between the R16 and computer... And I've suggested possible avenues to explore there.

However, if the clicks are getting in to the R16 directly, the recordings aren't 'good' and some further investigations are needed.

Assuming the R16 can record in other situations without clicks, then they must be due to external interference, and given that the connections from DI boxes to inputs are now balanced, the likelihood is that interference is getting in to the cabling prior to the DI boxes... Most probably via the mass of unscreened and unbalanced wiring/switches on your panel.

[robertkjr3d]

I am confused.

I was under the impression that recordings made on the R16 now were 'good' which I took to mean click- and whistle-free.

That being the case, the clicks must surely be an artefact of the audio data transfer between the R16 and computer... And I've suggested possible avenues to explore there.

However, if the clicks are getting in to the R16 directly, the recordings aren't 'good' and some further investigations are needed.

Assuming the R16 can record in other situations without clicks, then they must be due to external interference, and given that the connections from DI boxes to inputs are now balanced, the likelihood is that interference is getting in to the cabling prior to the DI boxes... Most probably via the mass of unscreened and unbalanced wiring/switches on your panel.

I'm not talking about recording via SD-Card without USB... Yes you are confused.

I'm talking about when connecting via USB. And you turn on Cubase on the computer. A test can be shown exactly what I'm referring to: When nothing is running or recording. It simply being connected. The Sub channel does not run through a DI-Box, because it is a straight switched RCA/Composite cable. And you can see noise lights on the physical 'R16' device. I only stopped seeing it... when putting in a 'ground-loop-isolator' on that channel. But I'm likely still getting 'electical power noise' coming from the USB line, that is causing the 'pops'.

When recording without USB... I'm fine.

[Hugh Robjohns]

So just to clarify, can you conform or correct the following:

The R16 is making click-free recordings from the amp on its own.

The clicks are heard/recorded in the R16 when connected via USB to a (grounded) computer.

Clicks are heard when the sub/LFE channel is not connected to the R16 via a DI /transformer isolator.

I'm sure it's obvious, but if the above is correct there will still be a ground loop between the computer and amplifier.

[James Perrett]

Are you hearing the clicks when monitoring the inputs of the R-16 directly (with the balance control above the master fader fully anti-clockwise)? If you are monitoring the audio after going through the computer then, even if not recording, it is still probably a buffer issue.

[robertkjr3d]

So just to clarify, can you conform or correct the following:

The R16 is making click-free recordings from the amp on its own.

The clicks are heard/recorded in the R16 when connected via USB to a (grounded) computer.

Clicks are heard when the sub/LFE channel is not connected to the R16 via a DI /transformer isolator.

I'm sure it's obvious, but if the above is correct there will still be a ground loop between the computer and amplifier.

1) The R16 is making click-free recordings from the amp on its own.
Yes
2) The clicks are heard/recorded in the R16 when connected via USB to a (grounded) computer.
Yes
3) Clicks are heard when the sub/LFE channel is not connected to the R16 via a DI /transformer isolator.
Your 3rd item is confusing to me too. (as you have written it)
I brought up the 'sub' channel because it is a straight connection. It comes out of the receiver as a RCA/Composite cable. It is not speaker-level. It is not sent through a DI-Box. And if not sent through a 'ground-loop-isolator' either, you can see noise on the line. That is when the USB cable is connected (and cubase is running).

The other lines likely have the same noise as well, only it is suppressed. It shows up as pops and clicks. This is the same item that brought up the original posting.

I've already purchased the USB-item. Mentioned a few posts ago.
Its supposed to handle (ground-loops, Electritcal noise caused by power-over-USB). It'll make it so I'll power the 'R16' through an USB-C 5V charger instead of the computer or the USB-Extender.

[Hugh Robjohns]

I brought up the 'sub' channel because it is a straight connection. It comes out of the receiver as a RCA/Composite cable. It is not speaker-level. It is not sent through a DI-Box. And if not sent through a 'ground-loop-isolator' either, you can see noise on the line. That is when the USB cable is connected (and cubase is running).

As mentioned above, without a ground loop isolator, this connection will be making a ground loop between the computer and amp... And ground loops result in unwanted noises...

There is zero point in isolating some channels and not others... All six outputs need to pass through isolators or one form or another. Personally, I'd run them all through DI boxes (the attenuator would be set at 0dB for the RCA sub output.

I've already purchased the USB-item.

Hopefully it will solve your problem without introducing another.

[robertkjr3d]

While I'm waiting on that....
I will post that: Besides some misgivings on the part of some on this.

It is a working system. And with some editing, the following piece is from star-trek is very difficult to tell from the original source materal. It would be nice to see if I can record in even better format like even 48000 samples or 96... but this was recorded in 44100.



I suppose if I recorded a two-channel piece... turned off the sub-woofer (so that there was no cross-over-point issues). Posted just a few-seconds, and in a format that more people could understand, instead of these multi-track formats. That wouldn't violate any big issues here, and you could see this device is on the level.

Note: Its hard to get the gain knobs on the 'Zoom R16' to be at just the right spot for each channel. I wish there were more lines drawn with numbers next to it. Or stop spots on the gains. So you could tell you were in exactly the same spot for matching some channels. I'm sure I'll get a groove at it eventually.

[robertkjr3d]

Update...
As Hugh suspected. The IFI-USB device did nothing. I'll return it.

And upon further testing:
My problem may be closer (or was) to do with buffering and/or just can't handle the traffic load with the extender. I believe Hugh, tried to suggest as much.

I started testing at 88200/24bit/512-buffer.
... And received no clips and/or pops!

There is noises that the 'R16' picks up when not running anything, as mentioned (at least visibly, or audibly, if I jam the headphone volume all the way), especially when the USB is connected. However, when enough 'signal' is applied, then the 'signal to noise' ratio is good enough. Even the very quiet parts of music-pieces are good.

I did promise to post a 2-CH piece... I'll get to it.

THANK YOU ALL FOR YOUR HELP!!

[Hugh Robjohns]

[robertkjr3d]

Here is the Stereo 2-CH piece I was promising.
It is 38seconds of 'Uncharted' by 'Sara Bareilles'.
https://drive.google.com/file/d/1wUJJOa1EigWrIoq9d1eLl00ZnNMumFIz/view?usp=sharing 13.4mb FLAC format.
Source was a MP3 --- now recorded through the box.

What's different? Since this was a completely different process, than the multi-channel recordings. I missed a step, and forgot to turn off the 'Room-Correction' and 'Equalizer'.
So the vocals are a little louder in the recording than in the .mp3, thats the first thing I noticed. Will I do it again, to correct it? No.

Here are comparison graphs... the box on top. The original below.


By the way I am keeping the USB-IFI. In testing, the sound seems to be just a hair better with it, than with-out it. Maybe that's just in my head.

I do have a question: How would I redesign the box to have only 1-Switch? Or possibly 2. I say 2, because the sub-channel should probably still be handled separately, as it comes from the receiver (RCA), not banana-plug/speaker-level. Now I wouldn't consider doing this until next year. The wife would not want me to spend any more time with wires and stuff all over the living room... anytime soon hehe. Maybe they make some sorta switch-arrays. Of course, they would need to be decent voltage requirements, with good wire gauge. In the course of this, we did figure out that the 'left', 'right', 'Center'... speakers all share the 'negative' wire. But I should still be careful how, or if I wire them together, because it could cause cross-talk.

[Hugh Robjohns]

I do have a question: How would I redesign the box to have only 1-Switch? Or possibly 2.

The obvious solution is suitably heavy-duty relays for the signal paths, all controlled from one or two switches as you suggest, with a suitable power source to activate the relays.

[robertkjr3d]

I do have a question: How would I redesign the box to have only 1-Switch? Or possibly 2.

The obvious solution is suitably heavy-duty relays for the signal paths, all controlled from one or two switches as you suggest, with a suitable power source to activate the relays.

I'm having trouble even googling this. What am I even looking for? I tried multichannel relay, that didn't work.

[Hugh Robjohns]

It would need to be custom-built, using individual relays for each channel with contacts capable of handling the power output of the amplifier.

[robertkjr3d]

So I've found that for the 2 (Dual-DI-Boxes) that I have...
I found that only one-side has to be switched to 'ground-lift' the other-side 'ground'.

I think its because of the internal wiring:

Both sides are wired to the chasis. If I flip both sides, the same (on ground-lift). It cross connects... enough that I can hear it on certain select frequencies. There is some metallic sounds.

The original noise issue seems to still be taken care of... regardless.

Note: That image above comes from a amazon-customer-review.
2nd Note: I also have a Single-DI-Box. I have two duals. And one-single.

Btw...(todo with my last posting) I have found that I can change my switch-wiring to 3P3T.... Then I would need just 2-Switches. One like this: https://www.amazon.com/dp/B01IZ5ZFYC/?coliid=I3GZWBX6I5LE2F&colid=14YX646C3B5PW&psc=1&ref_=lv_ov_lig_dp_it

But... I'm not in a hurry to do so.

[shooking_sybase]

I had something very similar with my Zoom R16 and a Soundblaster Live 5.1 external soundcard. Put up with for years. Then replaced my USB cables with ferrite core - see https://youtu.be/7DgvkrMVrjo

High pitch noise gone. Very happy with the result

[ef37a]

I admire you ingenuity and hard work frien but why did you not mouny all the swiches and connectors on in a metal box? Aluminium is only a little harder to dril than wood (?)

And whilst is is perfectly acceptable to wire everthing in single, unscreened cable the whole lot should be enclosed in a earthed box. Unscreened wires will also crosstalk (actually, screened is not THAT much better. Key to low Xt is as low a source impedance as you can get sub 100 Ohms if possible. )

Best you can do is make sure 'outputs don't run parallel to 'inputs and whist keeping wires short seems admirable better to have them long enough to stay tight to the metal box (whch of course we do not have!) As it is you have an 'array' Jodrell Bank would be ptoud of!

I have to say I am with the others in that I don't quite see the function? Sorry to be so pessimistic but I really do think that system needs to be better engineered.

Dave

[robertkjr3d]

I've been using this box for years now, to rip Streaming multi-channel audio, and it works like a charm. The quality is extremely high. I'm not sure any of you have the ability to play multi-channel FLAC files or the equipment to do so. And if I did share one, I feel like I would be breaking the law. So I won't share any. Now that you can't really find physical media like I did back during the time when I built this device, I'm sure glad I have it.

Could it be designed better? Maybe, but it does work. I am very picky when it comes to audio, so believe me, generally it is the 'Streaming' quality that is the issues, not the wires-cross talking, or my equipment, or I don't believe my design is at fault. When I'm relying on Amazon to give me 5.1 audio... on some movie, that's usually where my quality issue lies. However, usually a newer movie from Disney+ will result in a higher quality recording.