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High pitched bass on subs?

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High pitched bass on subs?

Postby mikehende » Tue Nov 13, 2018 9:16 pm

Oh God, so very tired of these music equipment issues sighhhhhhhhhhhh

All of a sudden guys I am now hearing like a very high pitched bass tone coming from both my Sonic dual 18 and also my Cerwin Vega Jr. Earthquake. I am suspecting cable issue as have tried bypassing the Ashly xover and tried 2 different EQ's or maybe this is coming from the mackbook? This Saturday I will test with a windows laptop but if you guys should have any ideas so I can be prepared please?
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Re: High pitched bass on subs?

Postby blinddrew » Tue Nov 13, 2018 10:50 pm

Remind us of your full set-up please Mike? What's into what via what.
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Re: High pitched bass on subs?

Postby mikehende » Tue Nov 13, 2018 11:13 pm

Oh Sorry. Macbook into Numark Preamp into klark Teknik EQ into Ashly xover into Crown Amps with Sonic Dual 18 and CV 18 subs.

I tried without the Preamp then tried without the xover but same deal.
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Re: High pitched bass on subs?

Postby Hugh Robjohns » Tue Nov 13, 2018 11:25 pm

I'm guessing you are using an unbalanced output direct from the laptop and have a ground-loop problem.

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Re: High pitched bass on subs?

Postby mikehende » Wed Nov 14, 2018 12:24 am

Ok but I have had this same setup for years now so why now? i have been using regular 3.5mm to dual rca cables from the Laptop's Headphone OUT.

https://www.sweetwater.com/store/detail ... YYQAvD_BwE
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Re: High pitched bass on subs?

Postby Hugh Robjohns » Wed Nov 14, 2018 12:32 am

The audibility of ground-loop noises is determined partly by the current flowing in the mains supply's earth wiring, and that will be different in different venues, and may well also vary in the same venue at different times of day, or with different things powered up in the venues. That's one reason why ground-loops can be so frustrating to resolve.

If it is a ground-loop via the laptop, unplugging its mains supply and running on battery power should make the noises go away.

However, there are other possible sources of noise. There could be ground-loop issues between other devices in the system -- especially if you are using any unbalanced connections between EQ, x-over, amps etc. Or there could even be a problem with a ineffective earth for the laptop...

When trying to resolve problems like this you have to be extremely methodical, and work back stage by stage through the system until you find the problem. So start with just one amp and one sub. Is that clean and noise free? If it is, check the other amp/sub combo. Then connect one amp to the x-over, then the other, then the EQ to the x-over, and finally the laptop. If the unwanted noises appear at any stage you'll need to work out what it is about the connection you've just made that's causing the problem...

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Re: High pitched bass on subs?

Postby mikehende » Wed Nov 14, 2018 12:48 am

Ok thanks will do. yes there is some strange stuff going on somewhere between the equipment, when I had tried certain configs, one side of the eq would not work, then if I used a splitter to run the low sub out from the xover into both channels of one amp one sub would not work e.t.c.

I have had strange issues in the Garage in the past which led to suspect electrical interference issues so that could be it surfacing again. I will know more after I throughly break down and test everything more thoroughly this time.
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Re: High pitched bass on subs?

Postby mikehende » Mon Nov 19, 2018 3:29 pm

So guys, it was the preamp which was shorting. I had issues with it in the past and had fixed it but seems it's problem has surfaced again, problem solved, appreciate the help!
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Re: High pitched bass on subs?

Postby Hugh Robjohns » Mon Nov 19, 2018 3:46 pm

:thumbup:
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Re: High pitched bass on subs?

Postby Martin Walker » Mon Nov 19, 2018 9:19 pm

Thanks for posting Mike - someone else might have a similar problem and benefit from your solution 8-)

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Re: High pitched bass on subs?

Postby mikehende » Mon Nov 19, 2018 9:46 pm

Yes, I always keep that in mind whenever I post for help.
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