Hi Keith - thanks for replying. For the Shure, that makes sense. For the buzz, I only.mention that it still buzzes without the lead plugged into the guitar to confirm the issue isnāt the guitar itself. The buzz is the same.when plugged into the guitar and doesnāt go away when I play. It comes through on the recording fairly loudly.
Mains hum issues like this can be caused by a lot of reasons, and can be difficult to track down. So I have some follow-up questions:
What guitar do you have? What sort of pickups.
Also, what are you plugging the Focusrite into? A laptop? If so, is the buzzing the same if the the laptop connected to the power supply and when itās running on battery?
Does the buzzing change when you rotate the guitar around (point the headstock in different directions).
Is there anything else plugged in and connected to the audio interface, such as a guitar amplifier?
Cheers,
Keith
Thanks again. No, moving the guitar in any way makes no difference - nor does changing the guitar. Iāve used a tele with a neck humbucker and a strat with 3 single pickups.
Iām plugged into a laptop which generate no buzz in other circumstances - recording just form the mic through the Focusrite is fine, as long as nothing is plugged into the second input.
Itās more than a faint background hum, its a real static buzz.
What about if the laptop is unplugged from the power?
The guitar is connected directly to the AI, and not via an amp?
Cheers,
Keith
So you have a tele and a strat directly plugged into the focusrite with the guitar cable?
Do you use an amp simulator software in Ableton to play with your plugged-in Electric guitar ? If yes, do some test with the gain on the audio interface. Lower it. The green halo on the focusrite was way too much for amp sim for me (producing a lot of buzz and hum).
If no amp simulator, one comes free on the focusrite website, you might try it. Playing without amp is not the intended use case of the audio interface.
I tried running the laptop without a power cable - no change. No amp involvedā¦
Not both guitars a the same time. But no, Iāve not been using an amp or amp simulator - the Focusrite setup videos say to just plug in direct.
Well, to make an electric guitar sound right, you would need some sort of amp or amp simulator. This could be software running on the laptop.
But without it, you can record the guitar but it wonāt sound right.
However, your answer helps eliminate one thing.
Do you get the hum still with just the guitar connected directly to the AI, and the microphone cable disconnected?
Cheers,
Keith
I love that you are trying to solve this for me! Yes I tried it on its own and with the 1 and 2 inputs swapped. It has me stumped.
Solution! I plugged in my Taylor with the lead it came with. No buzz. I used the Taylor lead with my electric guitars. No buzz. Just for fun, I tried the other lead with the Taylor. Buzz. It wasnāt a cheap lead either, but there you go. The plugs donāt seem to unscrew to check for a loose connection in the lead, but that must be it. Iāll invest in some better quality leads. Thanks again Keith for problem-solving!
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it may not be a loose connection. If you had only one wire connected, youād probably not hear anything. Better cables will be twisted pair, and best will be shielded twisted pair.
The shielded have a grounded wire mesh or foil around the conductors that helps to reduce noise getting on the signal wire.
Good chance your ābadā cable is neither of these.
Thereās only two connectors on an instrument cable, so thereās no way for an additional shield to be connected to ground.
Instrument cables should be two-wire coaxial (so a central core and an external shield). This is presented via a 2-connection jack plug, known as a āTSā jack (āTipā and āSleeveā). The sleeve should be grounded on the amp end (or, in the case of DI into an Audio Interface (AI), it should be grounded thereā¦ more on that in a bit.
image credit: Type and Usage of Important Studio Cables. | Thaddeus Maximus's Weblog
The shield is used both as a ground point and as a return path for the guitar signal so, yes, if the shield is broken you would get no signal.
Hum caused by the cable points to a poorly designed or damaged shield in the cable or, (possible but less likely) in the plugs. That doesnāt necessarily mean the cable is ācheapā: excellent quality coaxial cable, suitable for use in instrument cables, is available, off-the-shelf, for less than $1 (USD) per meter.
Itās possible, for instance, for the shield wires to be broken in the cable such that the shielding is not complete, but thereās still enough electrical connection for the signal to get through.
Regarding Audio Interfaces, whilst full guitar amps usually have excellent grounding, thatās not always the case for AIs. The grounding there is often provided by the USB Interface (especially for ābus poweredā devices) and a lop of PCs and laptops have poor grounding on the USB.
This is especially the case where you are running the AI from a laptop thatās being powered by battery. In that case, the ground is āfloatingā (i.e. ānot grounded at allā).
On the other hand, if you are running a laptop with a noisy power supply, then this can āleakā into the laptop power and cause noise problems.
And if you are using an amp or an audio interface which has its own power supply, then you can get ground loops between the laptop power feed and the amp/AI power feed.
Cheers,
Keith
Thanks for the picture. I should have grabbed one in my comment! I was also thingking of the TRS cables Iāve seen, so thanks for the correction.
I would think a damaged shield (or signal) would make the cable sound scratchy if you wiggled it. Iāve had more occasions for trouble with the connector on the guitar side than the cable.
I donāt have a respected audio interface. My go-to is a cable with USB on one side and 1/4 inch on the other. For something like the Focusrite, what is the mechanism for hum to get into the analog? It wouldnāt matter on the USB signaling side. Wouldnāt a respected name be expected to do a good job of designing the analog side to reject that kind of noise? I noticed you said that the Focusrite has its own power input, not coming from USB, so there should be no problem with supply sag due to long or lossy USB cable.
TRS are for either stereo, or mono balanced. In the case of mono balanced, the additional wire is used to carry the phase-inverted version of the signal. These are more resistant to electrical noise because the noise tends to affect both the in-phase and out-of-phase signals the same, and can therefore be cancelled out.
But balanced cables are never used as instrument cables. Stereo cables can be used on some guitars, but itās very rare.
(Itās the same cable, of course, itās just how the cable functions).
If it affected the connection, then yes. If thereās enough wire still to make the electrical connection then, possibly not. Although I have had damaged cables where flexing the cable at a particular point caused a slight scratching sound, pointing to a partial failure in the shielding at that point.
āScratchyā connections are more associated with the plug ends where the shield wires (or foil) are usually bundled and soldered together to make the connection before being soldered onto the plug terminal, and the solder joint may be ādryā or even not properly soldered and just touching. The scratchy sound in this case is caused by the change in resistance or even occasional small disconnections.
Thatās fine if it works for you.
The mechanisms are the same in both case. The AI ācableā and an AI āin a boxā like the Focusrite fundamentally do exactly the same thing, and work in the same way.
A single-channel Focusrite isnāt necessarily ābetterā than your cable, although the Focusrite will be more flexible as it will support balanced mic inputs and phantom powered mics, as well as instrument and line inputs, and will support local monitoring, etc.
Personally, I recommend the Behringer UMC range over the Focusrite: they are typically as good or slightly better, and you arenāt paying a premium for the name.
In practice, some of the very cheap guitar to USB cables tend to be a bit noisy, or to have higher latency. I suspect the higher latency is because they havenāt had proper drivers developed for them, more than anything else.
As for the mechanism, it can get into the analogue signal from a poorly shielded cable, or the pickups suffering from electrical interference. This is more likely with single-coils. And itās more common in electrically noisy environments. Nearby fluorescent lights are often very noisy and a common cause of hum.
But it can also get into the analogue side through the USB connection. If the unit is powered by USB, which comes from a PC/Laptop power supply thatās noisy, some of that noise can be injected into the signal. This is because all AIs have some sort of input pre-amp before the A/D converter, and that pre-amp references the power supply. If that reference has hum or other electrical noise on it, the resulting pre-amp output will have hum on it too.
Again, better AIs may do some filtering of the USB power supply to reduce this, but itās still a potential problem.
Laptop power supplies can be a particular problem, as they normally use cheap switched-mode power supplies. The way these work naturally injects all sorts of frequencies onto the power output, unless they are filtered out. And many cheap laptop power supplies donāt have great filtering.
The only place an AI can, reasonably, have āgood noise rejectionā is within the design of its own circuits, grounding of any metal chassis, etc. But this isnāt usually where these problems occur. Usually the electrical noise is already on the signal when it arrives at the AI.
If you canāt differentiate noise from signal, then how do you reject it?
The better approach is to avoid the noise in the first place with well shielded circuits, cables, and guitar cavities, etc.
No, I donāt think I said that. Most of the consumer-end Focusrite AIs are USB powered. As are similar models like the Behringer UMC series.
Well, thereās limits on how long USB cables should be, and itās fairly unlikely you would get significant voltage drop in a typical USB cable (a few metres), so I wouldnāt worry about that.
The biggest thing to watch for with audio interfaces which have their own power supply, is ground loops, especially with laptop power supplies.
Cheers,
Keith
Keith
Please move this qurstion to another thread if Iām asking it in the wrong place.
You mention using Focusrite and Ableton, in sequence almost, to deliver sound to OBS. I do not understand how that would be done. Please can you explain how?
Iāll appreciate any insight you can offer.
Brian
I canāt move it. But, in a nutshell, you use OBS to receive the video from a video source, and have a DAW running (any DAW, it doesnāt have to be Ableton) to receive the audio from your audio input (from an audio interface).
Obviously, if you do this, you can record the audio in the DAW and the video on OBS, but they are disconnected.
The idea is you can join these applications by connecting a monitoring output from the DAW to the audio input of OBS. To do that on Windows or Mac, you need a separate application.
For Windows you can use tools like VoiceMeeter, ReaStream, or Jack
For Mac you can use Loopback.
Modern Linux distros have this capability built in via Pipewire, and you can use qpwgraph to configure the connections (install with sudo apt install qpwgraph, etc. or your package manager)
A great explanation, using Reaper as the DAW, was put together by @TheMadman_tobyjenner
Open Mic Tech Talk (Advanced) Connecting Reaper, OBS and Zoom Using Reaper ReaRoute
Cheers,
Keith
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Thank you Keith.
Brian