ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Scott Carpenter on February 04, 2011, 04:08:47 pm

Title: How to wire in parallel and series/parallel w/ speakon cables
Post by: Scott Carpenter on February 04, 2011, 04:08:47 pm
I am new to the world of speakon cables (Only done home audio up until this point)

Which Speakon cables will I need to wire:

1: 2 JBL JRX125's in series/parallel into a bridged 4ohm load on a Behringer EP4000 amp


2: 2 JBL JRX115's in parallel into a single channel on a Behringer EP4000 amp (creating a 4ohm load)

3: 2 MACH M151i's in parallel into the other channel of the second Behringer EP4000 (creating a 4ohm load)

Here is a link to the M151's specs
http://www.martinpro.com/service/downloadfile.asp?name=SP_M151I_EN.pdf&cat=85

Thank you very much for your help

Title: Re: How to wire in parallel and series/parallel w/ speakon cables
Post by: Mark Mattocks on February 04, 2011, 04:48:16 pm
Scott,

1 - I don't know of a way to series/parallel 2 cabinets. Series/parallel is more commonly used with 4 drivers to keep impedance higher - 4 8ohm drivers in series/parallel will give you an 8ohm load.  With 2 cabinets, your options are series OR parallel.  In series, the two cabinets will give you a nominal 8ohms; in parallel, a nominal 2ohms. You would need to make a junction box or a funky 'Y' cable to series the cabinets and I don't think that is a good idea.

2 - You can parallel the cabinets by simply jumping through one cabinet to the other. Since the JRX series only have 1 NL4 and 1 1/4" as connectors, you would need to use the 1/4" jack as an input or a through.

3 - The same as above, but you need both in and out on NL4 cables.

Instead of jumping through cabinets, you could wire an output panel on your amp rack with parallel NL4 outputs.
Title: Re: How to wire in parallel and series/parallel w/ speakon cables
Post by: George Dougherty on February 04, 2011, 11:56:16 pm
+1 Daisy chain for parallel. 
Build a series capable adaptor box to handle series if you really need to.  I've always thought it better to just use another amp than up the voltage handling and power requirements with boxes in series.
Title: Re: How to wire in parallel and series/parallel w/ speakon cables
Post by: Mac Kerr on February 05, 2011, 12:01:40 am
I am new to the world of speakon cables (Only done home audio up until this point)

Which Speakon cables will I need to wire:

1: 2 JBL JRX125's in series/parallel into a bridged 4ohm load on a Behringer EP4000 amp

Series/parallel requires more than 2 speakers. Two speakers can be either in series, or in parallel.

Mac
Title: Re: How to wire in parallel and series/parallel w/ speakon cables
Post by: Brad Weber on February 05, 2011, 08:00:55 am
1: 2 JBL JRX125's in series/parallel into a bridged 4ohm load on a Behringer EP4000 amp

2: 2 JBL JRX115's in parallel into a single channel on a Behringer EP4000 amp (creating a 4ohm load)

3: 2 MACH M151i's in parallel into the other channel of the second Behringer EP4000 (creating a 4ohm load)
Two JRX125s can be wired together as an 8 Ohm load or a 2 Ohm load.  Why not just put one JRX125 per channel, the difference between 2,400W into two speakers and 950W for each speaker is 1dB.  And if you had one JRX per channel that's a maximum output of 130dB for each speaker while the max output for the JRX115s would be 125dB and the Mach 115s would be 127dB.
Title: Re: How to wire in parallel and series/parallel w/ speakon cables
Post by: Randall Hyde on February 05, 2011, 11:17:39 am
I am new to the world of speakon cables (Only done home audio up until this point)

Which Speakon cables will I need to wire:

1: 2 JBL JRX125's in series/parallel into a bridged 4ohm load on a Behringer EP4000 amp
I assume you mean in series. The JRX125 columns are 4 ohms each. In parallel they'd be 2 ohms which is probably too little for your Behringer amp.

Quote
2: 2 JBL JRX115's in parallel into a single channel on a Behringer EP4000 amp (creating a 4ohm load)
No. Each column is 4 ohms. Put them in parallel and you've got 2 ohms. I'm pretty sure that's half what the Behringer amp likes. I could be wrong, but Behringer isn't known for making amps that work down at the level.

Quote
3: 2 MACH M151i's in parallel into the other channel of the second Behringer EP4000 (creating a 4ohm load)
These *are* 8 ohm speakers. You can connect two of them in parallel to get 4 ohms. The Behringer *ought* to be able to handle 4 Ohms okay, but based on my past experience with Behringer equipment, I'd operate them at twice their lowest impedance rating -- they'll last a lot longer that way.

Bottom line, as others have suggested, you need two amps. I'd use the EP4000 on your subs and get something like an XTi 1000 or 2000 for your JRX125 cabinets.
Cheers,
Randy Hyde
Title: Re: How to wire in parallel and series/parallel w/ speakon cables
Post by: Brad Weber on February 05, 2011, 01:21:04 pm
No. Each column is 4 ohms. Put them in parallel and you've got 2 ohms. I'm pretty sure that's half what the Behringer amp likes. I could be wrong, but Behringer isn't known for making amps that work down at the level.
The JRX115 is a nominal 8 Ohm box and the EP4000 does have a 2 Ohms per channel rating, so two JRX115 in parallel, which would be a nominal 4 Ohm load, on an EP4000 channel should be fine.