Speakers mute using pass-through

[dansleeth]

Excuse my lack of knowledge when it comes to PA systems.

I currently have a Yamaha EMX312SC powered mixer hooked up to a JBL PRX353 powered speaker via an RCA>1/4" coming from the Rec Out.

The JBL is connected to another JBL via an XLR pass-through (XLR out of the first speaker, into the second).

However, when the second speaker is connected, no sound comes from either speaker.

This is not the case if I have a Speakon or 1/4" Jack coming out of the mixer into the JBL (which has a Jack/XLR combo). It only happens when I am using the Rec Out.

I get distortion when using the Speakon/Jack due to them both being powered, which is why I have resorted to using the red and white RCAs.

Could someone tell me where my problem lies?

Thanks in advance for any assistance!

 

[conanski]

DO NOT connected the amplified output of the powered mixer to these speakers you will blow up the speaker inputs.

You need to use a 1/4 TRS to XLRF cable from the mixers main outputs to the speaker input(Make sure it's the input), and then connect with an XLRM from the output(thru) jack of that speaker to the input of the next.. or you could just connect directly from the mixer via the other output jack, that way you have stereo sound.

 

[dansleeth]

Thank you for your response. I will try a 1/4" jack out the front of the mixer to the speaker. Does this mean I cannot have stereo unless I have a cable running to each speaker? Is there any way I can send one cable to the first speaker and have it send one of the channels to the other speaker?

Thanks again for your response!

 

[conanski]

Does this mean I cannot have stereo unless I have a cable running to each speaker?

Yes, you need a cable from both the L and R outputs of the mixer to separate speakers to get stereo sound.. no way around this.


BTW.. hopefully you didn't just buy all this stuff new. If you did I'd suggest returning the mixer and getting a non powered version as there is no need for the amplifiers in it.

 

[turk 182]

maybe he has passive monitors he needs to run off the amp in the mixer (most i've seen have some provision for selecting between main and monitor assignments of the amp.)

with sound cutting out when a second speaker is linked via the XLR/mic connection check that it isn't a mis-wired/mis-pinned mic line.

and yeah i agree with Conanski be careful not to use the built in amp's output into a powered speaker's input.

 

[conanski]

with sound cutting out when a second speaker is linked via the XLR/mic connection check that it isn't a mis-wired/mis-pinned mic line.

I suspect that the RCA to 1/4 cable he was using originally is actually an insert type cable with both channels patched to the tip and sleeve. Connected to the balanced input of a powered speaker the first thing it sees is a differential amp that cancels everything that is common on pins 2 and 3(usually just noise) and will only amplify what is different on both wires, but a stereo recording often has a lot of the content reversed in polarity to get that 3D stereo effect so the pin3 polarity flip of the input amp puts both signals back into the same polarity and you get sound. But connect another speaker and you introduce another differential amp with another polarity flip and total cancellation takes place. If the source signal is mono to begin with this doesn't happen.

 

[turk 182]

without details of the cables used anythings possible.

i am a little confused as to how paralleling /daisy chaining a second balanced input results in a polarity flip that causes cancellation?

i can say that feeding a stereo signal across a balanced input will get you sound and to me it sounds more like Karaoke tracks with the mid range content varying based on phase differences in the two channels (the sum/result of left + right{phase reversed}) i guess that's what you meant by 3d effect

 

[turk 182]

is the model number of the jbl speaker correct?

 

[dansleeth]

Thank you all for your responses. I copied the model number from an old service invoice laying around in the office, but I've just gone up the ladder and on closer inspection the correct model number is JBL PRX535 sorry about that.

I work in a school and all this gear already existed before I joined. I am however, responsible for buying the wrong cables! This is the exact RCA I bought:

Phono - Stereo Jack Pro Cable, 6m at Gear4music.com

I guess it is time to buy a 20m jack-to-jack to reach the other speaker...

Thanks once again!

 

[dansleeth]

- To add

I've just had an issue arise, which has happened before. I have Mics going in via XLR and a PC going in via the Tape In (RCA) on the mixer and going out to the speaker via the Rec Out (RCA). Occasionally the sound just stops and refuses to work for a while. It eventually comes back on its own (after 5 minutes or so). Does this relate to my wiring or something? Neither the PC or Mics can be heard.

 

[turk 182]

i would still check all mic lines used in conjunction with this sound system to ensure none are mis-wired.

 

[conanski]

I've just had an issue arise, which has happened before. I have Mics going in via XLR and a PC going in via the Tape In (RCA) on the mixer and going out to the speaker via the Rec Out (RCA). Occasionally the sound just stops and refuses to work for a while. It eventually comes back on its own (after 5 minutes or so). Does this relate to my wiring or something? Neither the PC or Mics can be heard.

Just to reconfirm you do not have the speaker outputs of the mixer connected to the speakers in any way? Disconnect 1 of the RCA connectors at the Rec out.

The Rec out is the wrong thing to use to drive the speakers anyway because you have no master level control, the mixer just isn't designed to be used that way. You won't damage anything but you don't have the control you're supposed to have. Get the proper cables and connect to the main line outputs on the front of the mixer.