speaker out from amp and speakers on patch bay?

[bamb00]

hi

I'm trying to put my surround and surround back speakers as well as surround and back surround speaker out's from a 7.1 amp on a TRS patchbay.

I have cheap speakers hard wired to the ceiling and I just got some real nice JBL movie theater speakers for the back surround.
Netflix is mostly 5.1 so I'd rather have my back surrounds wired to the surrounds but a lot of HD tv/blue ray is 7.1 so I'd like to have the JBL's as back surround still using the cheap speakers as surrounds.
The patch bay will make it easier to switch monitoring configurations.

Is there any issues with soldering speaker cable to a trs (with nothing connected to the ring) connector and wiring the cable from the speaker out of the amp to trs connector all hooked up to the patchbay?

Thanks

 

[bamb00]

or would using xlr connectors be better and forget the patch bay?

 

[Boswell]

The general rule is never to put loudspeaker connections through an audio patchbay. This does not apply to powered monitors, of course, as those take line-level audio inputs.

If you want to patch loudspeaker connections, buy or make a rack panel with two rows of Speakon socket connectors and a set of short Speakon plug-plug interconnect leads.

 

[bamb00]

Thanks for the reply. good thing I asked. What about not using a patchbay but use 2 pins on xlr cables?

 

[Boswell]

I recommend that you don't use line-level audio connectors and cabling. Even if you never make a plugging-in mistake, the contacts on audio connectors simply will not take the current involved in loudspeaker circuits.

 

[bamb00]

ok thanks
Just to clarify, I use normal speaker cable out of the speaker out of the amp and from the input of the speakers, with Speakon connectors connecting the speakers to the amp in between?
Does the volume need to be down when swapping speakers?

 

[Boswell]

Yes about the cable, and this also applies to the short patching leads. Strictly speaking, the Speakon patch panel should consist of panel-mount sockets on the amplifier lead connectors and panel-mount plugs on the connectors going to the speakers. The patch leads would then be cable-mount plugs to cable-mount socket connectors.

I would advise turning the power off on every amplifier that is having its outputs patched.

 

[bamb00]

thanks for the reply. To save some money couldn't I just not use a patch panel, and have male speakon connectors from the amp's speaker outs, then have speakon female connected to the cable from the speaker ins?

 

[Boswell]

I'm not sure I have correctly understood what you are proposing, but if it's along the lines of having only one set of panel-mount Speakon connectors (sockets in this case) wired to the amplifier outputs and then have the loudspeaker trailing leads equipped with Speakon plugs, then, yes, that would work. Not so tidy, though.

 

[bamb00]

yes that's right. not so tidy but $100 cheaper

 

[paulears]

Speakons in a D mount patch panel will work well, but so too will XLRs, if you don't use XLRs for anything else - because cross plugging is expensive, repairs wise. XLRs can handle sensible power - after all, many PA manufacturers used XLRs for their high power cabinets for years.

 

[bamb00]

Good to know. So XLR's will work? I'm not going to blow up my amp or burn down my house?
Is it important to turn off the amp before swapping speakers?

 

[paulears]

The usual professional advice is to always turn off the amp before disconnecting or connecting speakers, but you also get told that you should drop the attenuators on bigger amps too, then restore them every time you've powered up. In practice, with good quality amps, you can connect speakers while they are powered up with no issues - or at least, in the 30 odd years I have been doing it, it's never caused me any grief.

There are a few issues, though. Most older professional quality PA amps had MALE outputs. This seems wrong, but the idea was to ensure you could never see an XLR cable on the floor, pick it up and connect 500 or more Watts of power into a microphone, which also has a male XLR connector. If you have your patch bay with male connectors, be aware that these pins can be touched with your finger. Typically you'll find around 80 or so volts on them when the amps are working , with a fair bit of current available. Tingles. Worse is that the XLR connectors are usually metal - so with a bit of fiddling, you could if you try hard, short them out. Usually, when being used for speaker level connections, the circuit is across pins 1 and 2 (or 1 and 3) NEVER 2 and 3. This means that if you do accidentally connect to a low level signal device, you might just get away with it, as the damage susceptible components are usually on 2 and 3, using 1 as a ground connection. Speakons in a D size cutout will cost you a small amount more, but can be a bit awkward to access if you have chunky fingers. Cheap, short XLRs are available pre made. If you are starting from scratch - Speakons make sense. If you already have some XLR bays, I'd use them.

Jacks for speakers are awful, and unreliable, and to prone to shorting and physical damage.
XLRs for speakers work fine, are safe, and economic - just the 'wrong' connector by current standards.
Speakons are the 'right' connector - just a bit chunky on a tightly packed panel. They do have advantages. You can use cable up to 4mm2, two circuits are available in each connector and they have better current capability than XLRs, which can only take smaller cables - 1.5mm2 is doable - bigger, a problem.

 

[Kurt Foster]

umm ..... errr .......... why hasn't anyone suggested a speaker switcher?

 

[paulears]

Because he wants to be able to repatch to cope with 7 channels out from (I presume) 2 or more inputs depending on the sources. A speaker switcher tends to just be a two channel device, although there's no reason you couldn't build one with logic circuits to prevent paralleling or cross patching. You could produce something with preset states, but seems a bit OTT, and expensive.

 

[dvdhawk]

A couple things:
Home theater systems are notorious for bundling in almost useless light gauge wire. Hopefully you've upgraded your in-house wiring to 12AWG or 14AWG speaker wire.
Down-firing ceiling speakers (especially cheap ones) often just muddy the sound stage and present more audio problems than they solve.

Of course, it's not advisable to connect / disconnect speakers under power, but the SpeakOn design is a vastly superior to any ¼" speaker connection in reliability, contact area, and short-protection. The D-series SpeakOn Paul mentions fits in the same size hole as a Neutrik D-series XLR panel mount connector and would offer the advantage of making contact with the - pole(s) before it contacts the + pole(s). If you must "hot-patch", that is much better than the alternatives. If you're not big on soldering, you can get them with screw terminals too.

But I have to ask, doesn't the 7.1 amp have a setting for 5.1 material, or some auto-sensing of the source material? Make/Model of the 7.1 receiver??