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Mar 31, 2019

Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Hi all. On the T4S whenever I use TRS 1/4" to XLR male cables from the main outputs of the T4S to a mixer/FOH via XLR I can hear background noise , which resembles rumble and hiss. Even when all channels are muted, master volume down and nothing plugged in the inputs, I can still hear the noise. The headphone output does not contain the noise. I've tried different cables (Mogami Gold and Van Damme), and even a noise/hum eliminator in between the T4S and the FOH mixer, but still noise . However, when I use 1/4" TS to 1/4" TS cables the noise doesn't exist. Has anyone else experienced similar issues when using 1/4" TRS to XLR cables? It's important I use XLR connections, because it's easier when I turn up to gigs and connect to the FOH via XLR on the stage. Thank you Note: the firmware is up to date.

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Re: Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Hi obsidian,

Welcome to the Bose Portable PA Community. Thanks for your question.

I'm sorry you're hearing excessive noise from the T4S when you connect the 1/4 inch (6.3 mm) Tip-Ring-Sleeve output to an XLR input on a FOH/Mixer.

I just replicated your setup here.  When I set the input level on the FOH/Mixer to LINE LEVEL there is almost no noise. When I set it to MIC LEVEL on the FOH/Mixer, the noise level is much more noticeable. That's to be expected. The output of the T4S is line level.

Please try this.

T4S

  • Run backing tracks with the T4S
  • Set the trim lights showing solid green, with occasional flickers of red
  • Channel Volume at 12:00
  • Master Volume at 12:00



FOH/Mixer

  • Set the input level to LINE LEVEL (or if there is a 20 dB pad, turn it on)
  • Set the input trim on the FOH/Mixer so you get a solid signal with no clipping



Now turn down the Master Output of the T4S. How is the noise level now?

ST

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Re: Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Don't forget the noise GATE for each channel. It will effectively limit all noise below the threshold you set, independently, for each channel. 

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Re: Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Hi. I use the noise gate feature on my channels to help reduce ambient hiss from FX pedals, etc, which is normal. The issue I have is rumbling noise and low level static in the main output signal, even when the volume is turned all the way down. I thought it might be a grounding issue, hoping premium cables would help eliminate the issue, but no success. When I have music coming through the T4S the noise is less apparent, but when I stop playing or mute all channels (and even when I've completely turn down the T4S master volume) the noise is obvious.

Next I will try using 1/4" TS to XLR cables and see if that helps.

 

Thanks

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Re: Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Codydog19,

Please see this new discussion for your question.

T8S to L1 Model II white noise

Thank you,

Bose Pro Community Admin 

 

 

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Re: Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Hi obsidian,

obsidian posted:

Hi. I use the noise gate feature on my channels to help reduce ambient hiss from FX pedals, etc, which is normal. The issue I have is rumbling noise and low level static in the main output signal, even when the volume is turned all the way down. I thought it might be a grounding issue, hoping premium cables would help eliminate the issue, but no success. When I have music coming through the T4S the noise is less apparent, but when I stop playing or mute all channels (and even when I've completely turn down the T4S master volume) the noise is obvious.

Next I will try using 1/4" TS to XLR cables and see if that helps.

You will lose the balanced connection between the T4S and the FOH/Mixer. This will result in up to -6 dB in signal loss, and increase your vulnerability to line noise. Since it will lower the signal level hitting the FOH/Mixer, it may reduce the noise you are hearing now - BUT - a better solution is to turn on the MIC/LINE Level switch or -20 dB pad on the FOH/Mixer.  (or turn down the input trim on the mixer).





Thanks

Please see my post above - Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

before spending money on cables.

Thanks,

ST

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Re: Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Hi again. Thanks ST and Codydog19 for the extra info.

I tried the above tips and processes, but no success. I have both the T4S and T1. Here's what I tried today:

a) Cable 1/4" TS / XLR male

b) Cable 1/4" TS / 1/4" TS

c) Cable 1/4" TRS / XLR male

T4S using cables a and b = white noise, c (worst) = white noise and static/rumble.

T1 - a, b, c cables = minimal/normal white noise;

Note - this was tested with all channels muted on the Tonematch, and master volume at zero. I plug the Tonematch to the Mixer via the cable, and as I increase the Mixer gain the noise begins background noise. The mixer preamps are quiet on their own. Side by side the T4S has more background noise, but worst when using TRS to XLR cable. Whereas the T1 was surprisingly clear and low noise will any cable.

I'm lost with what to do next.

Thanks all.

 

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Re: Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Hi obsidian,

Thanks for the results of your tests.

obsidian posted:

Hi again. Thanks ST and Codydog19 for the extra info.

I tried the above tips and processes, but no success. I have both the T4S and T1. Here's what I tried today:

a) Cable 1/4" TS / XLR male

b) Cable 1/4" TS / 1/4" TS

c) Cable 1/4" TRS / XLR male

T4S using cables a and b = white noise, c (worst) = white noise and static/rumble.

If you are connected to the XLR inputs on the FOH and those inputs are set for microphone inputs (not line level inputs), then I can understand why you got these results.

T1 - a, b, c cables = minimal/normal white noise;

The T4S has a much higher output than the T1. With that comes a higher noise floor. You compensate for that by lowering the input sensitivity on the FOH mixer.



Note - this was tested with all channels muted on the Tonematch, and master volume at zero. I plug the Tonematch to the Mixer via the cable, and as I increase the Mixer gain the noise begins background noise. The mixer preamps are quiet on their own. Side by side the T4S has more background noise, but worst when using TRS to XLR cable. Whereas the T1 was surprisingly clear and low noise will any cable.

I'm lost with what to do next.

Thanks all.

Have you tried these steps from my post above?



Please try this.

T4S

  • Run backing tracks with the T4S
  • Set the trim lights showing solid green, with occasional flickers of red
  • Channel Volume at 12:00
  • Master Volume at 12:00



FOH/Mixer

  • Set the input level to LINE LEVEL (or if there is a 20 dB pad, turn it on)
  • Set the input trim on the FOH/Mixer so you get a solid signal with no clipping



Now turn down the Master Output of the T4S. How is the noise level now?



ST

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Re: Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Hi ST. Yes I tried the previous advice, plus the above. The noise level exists even when the  T4S master Output level is turned down - so it could be a grounding issue....I'm not sure. I noticed it again when I used a TRS/XLR cable to the FOH. Its sounds like the ocean. My friend was using a T1 with the same type of cable, but had no noise. I had to change to a TRS/TRS cable to eliminate the noise.  Thanks

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Re: Noisy main outputs from T4S when using TRS 1/4" to XLR male to FOH

Hi obsidian,

What kind of mixer is the FOH? Please give us the make and model designation.

Does it have a Mic/Line Level switch or a pad on the inputs?

Since the connection is fine using 1/4 inch (6.3 mm) Tip-Ring-Sleeve cables, it sounds like there's an issue with the XLR connection at the FOH end of the connection. Have you tried using different inputs on the FOH?

Is this issue specific to one FOH system? Have you tried the T4S with another mixer?

Thanks,

ST