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Author Topic: Speaker Hook-Up Problems  (Read 7161 times)

Jacob Robinson

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Speaker Hook-Up Problems
« on: October 22, 2011, 06:55:16 AM »

I hope I am missing a simple and obvious solution to this because I am tired of mind wrestling it over and over.  Here is what I am trying to do:

I bought a Behringer B205d personal monitor speaker http://www.behringer.com/EN/Products/B205D.aspx (for the sake of time, we'll leave my choice of products out of the equation, I know Behringer is probably not a favorite of too many member here) and I want to use it as a keyboardist/P&W Leader monitor.  This way She can have control over the keyboard volume and vocal mix without affecting the other floor wedges.  I only have two AUX sends so I can't dedicate a send to the B205d alone so I am trying to send the same signal to the B205d as to the amps that feed the other wedges. 

*Note the stage box where our snake terminates has both a 1/4" and XLR jack for each send (I would think that the 1/4" jack is TRS balanced, but not positive).  The problem here is that if I plug something into the 1/4" it cuts the signal to the XLR using both jacks at the same time is not an option.

Here are the ways I have tried to hook it up so far:

Stage box 1/4" >>> TRS Y cable >>> one side to floor wedge amp >>> other side to B205d.-------This does exactly what I want it to but it creates a buzz in the system.  (ground loop I assume)

Stage box XLR >>> XLR Y cable >>> one side to floor wedge amp >>> other side to B205d.-------Same problem as above.

Stage box XLR >>> B205d input >>> B205d output >>> floor wedge amp--------No humming problems, but the mini mixer on the front panel alters the mix sent out from the B205d, this defeats the purpose of being able to independently control the volume of the keyboard.

Stage box >>> floor wedge amp input >>> input/thru on floor wedge amp >>> B205d-------The creates the mix I want and there are no humming problems, but I get very little volume out of the speakers.  (is this due to an impedance mismatch?  (still grasping impedance and how it affects things)


It seems to me the best solution is splitting the signal right out of the stage box, is there a way to eliminate the hum or ground loop?

I hope this makes a little sense; it is hard to put this all into words.
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Tom Young

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Re: Speaker Hook-Up Problems
« Reply #1 on: October 22, 2011, 09:45:07 AM »

I hope I am missing a simple and obvious solution to this because I am tired of mind wrestling it over and over.  Here is what I am trying to do:

I bought a Behringer B205d personal monitor speaker http://www.behringer.com/EN/Products/B205D.aspx (for the sake of time, we'll leave my choice of products out of the equation, I know Behringer is probably not a favorite of too many member here) and I want to use it as a keyboardist/P&W Leader monitor.  This way She can have control over the keyboard volume and vocal mix without affecting the other floor wedges.  I only have two AUX sends so I can't dedicate a send to the B205d alone so I am trying to send the same signal to the B205d as to the amps that feed the other wedges. 

*Note the stage box where our snake terminates has both a 1/4" and XLR jack for each send (I would think that the 1/4" jack is TRS balanced, but not positive).  The problem here is that if I plug something into the 1/4" it cuts the signal to the XLR using both jacks at the same time is not an option.

Here are the ways I have tried to hook it up so far:

Stage box 1/4" >>> TRS Y cable >>> one side to floor wedge amp >>> other side to B205d.-------This does exactly what I want it to but it creates a buzz in the system.  (ground loop I assume)

Stage box XLR >>> XLR Y cable >>> one side to floor wedge amp >>> other side to B205d.-------Same problem as above.

Stage box XLR >>> B205d input >>> B205d output >>> floor wedge amp--------No humming problems, but the mini mixer on the front panel alters the mix sent out from the B205d, this defeats the purpose of being able to independently control the volume of the keyboard.

Stage box >>> floor wedge amp input >>> input/thru on floor wedge amp >>> B205d-------The creates the mix I want and there are no humming problems, but I get very little volume out of the speakers.  (is this due to an impedance mismatch?  (still grasping impedance and how it affects things)


It seems to me the best solution is splitting the signal right out of the stage box, is there a way to eliminate the hum or ground loop?

I hope this makes a little sense; it is hard to put this all into words.

Following the different things yoiu tried is a bit difficult, so I'll offer some suspicions and things to try:

You are correct that the 1/4 jacks on your stage box are probably TRS/balanced. If plugging into the 1/4" kills audio from the XLR, they may have used switching 1/4" jacks, which makes no sense but is the only way I can see this happening. Why don't you open up the stage box and visually confirm what is going on ?

You should also try using an XLR Pin-1 lift adaptor on one of the destination devices when plugging into two of them. Then try a direct box or barrel-type transformer. Also try both.

Make sure the Behringer is on the same AC power as the monitor amp.

If Behringer provides a schematic (unlikley, I think) look to see if the input is balanced or unbalanced. They may state this in the specs.

Then report back.
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Tom Young
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Jacob Robinson

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Re: Speaker Hook-Up Problems
« Reply #2 on: October 22, 2011, 10:16:19 AM »


You should also try using an XLR Pin-1 lift adaptor on one of the destination devices when plugging into two of them. Then try a direct box or barrel-type transformer. Also try both.



What would happen if I just de-soldered pin-1 in the cable to the B205d?  Would this accomplish the same as a Pin-1 lift adapter?
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Tom Young

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Re: Speaker Hook-Up Problems
« Reply #3 on: October 22, 2011, 11:37:38 AM »


What would happen if I just de-soldered pin-1 in the cable to the B205d?  Would this accomplish the same as a Pin-1 lift adapter?

Yes. All you need is to do this at one end. The receiving end is usually the preferred point to lift the shield. But since you are feeding two devices, you may want (need) to also try this at the send end.

Recommended reading:

http://www.rane.com/note110.html

http://www.bartlettmics.com/newsletter/newsletter%2010-09.pdf

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Tom Young
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Oxford CT
203-888-6217

Jacob Robinson

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Re: Speaker Hook-Up Problems
« Reply #4 on: October 24, 2011, 07:03:15 AM »

I ended up having success using a 1/4" TRS Y cable directly out the of the stage box and sending one side to the amp and the other side to the Behringer speaker. Turns out my hum was just coming from having the amps and Behringer plugged into different phases of the electrical panel. I switched them to the same outlet and away went the humming and I got the mix I was looking for.




Thanks for all you input!
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Tom Young

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Re: Speaker Hook-Up Problems
« Reply #5 on: October 24, 2011, 07:31:14 AM »

I ended up having success using a 1/4" TRS Y cable directly out the of the stage box and sending one side to the amp and the other side to the Behringer speaker. Turns out my hum was just coming from having the amps and Behringer plugged into different phases of the electrical panel. I switched them to the same outlet and away went the humming and I got the mix I was looking for.

Thanks for all you input!

Great !

(sometimes we get lucky and the problem gets solved with little effort)
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Tom Young
Electroacoustic Design Services
Oxford CT
203-888-6217

ProSoundWeb Community

Re: Speaker Hook-Up Problems
« Reply #5 on: October 24, 2011, 07:31:14 AM »


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