How to extend installed speaker cables that are too short?

[Les]

Originally Posted by mjl5007

I thought that might work, but feel much better hearing that it worked for you.

According to Neutrik's schematics for the NL4MP panel mount connectors, the round portion of the connector that sticks back through the panel is 24mm (~0.945") in diameter, so a 1" hole should be perfect. Slip the connector in the hole, drill a couple of 3mm mounting holes through the blank plate using the mounting holes in the connector as guides, and add a set of M3 nuts and bolts and it should work out just fine.

While 1" will work, it's not perfect. It's a little big and you have to make sure when you drill your 2 mounting holes that they are perfect or else you'll have a gap on one side of your connector.

It's hard to find a 24mm Punch but Greenlee makes a 15/16" punch, which works great. You can pick one up for $30ish dollars from several outlets (Grainger comes to mind).

It's much easier with the right tools.

In my mind if you're going to make your own then do it right and make it as good as the factory pre-built ones.

So, take into account the cost of the punch, the raw materials, and the time it takes you to actually put it all together the pre-built plates aren't that bad of a price.

[mjl5007]

Originally Posted by Les

It's hard to find a 24mm Punch but Greenlee makes a 15/16" punch, which works great. You can pick one up for $30ish dollars from several outlets (Grainger comes to mind).

It's much easier with the right tools.

In my mind if you're going to make your own then do it right and make it as good as the factory pre-built ones.

I absolutely agree with "do it right". A huge number of the things I've been working on 'fixing' around the church lately (in terms of both installation, like these too-short speaker cables that are the core of this project, and the components that make up our A/V/L systems) are because when it was done the first time, it was done the cheap-as-possible-but-still-work way, and I'm trying to make a point of how much less hassle and work it is in the long run to do it right the first time, rather than have to go back and fix it later.

As for the Greenlee punch, 15/16" is only 23.8mm... does it just make for a nice snug fit? Would something like this work instead? I realize it's a drill and not a punch, but it would get me a 15/16" hole and it's a tool that I'm sure I would find uses for in the future, so I don't mind the investment (particularly at $13).

Two more questions:

1. I took a look at the wiring again last night to confirm my planned approach will work, and realized that on one of the amps, we're powering two speakers off of each channel in parallel -- that is, there are two sets of speaker wires wired into each channel's binding posts. (We're using one channel for side fills and the other for subs, two speakers each). How would you recommend I go about accounting for this with my SpeakON wall jacks? Can I wire two sets of speakers in parallel on the back side of one of the NL4MP panel jacks? Or would it be better to have separate jacks for every speaker, and come up with something between the amp and the wall jacks to run two speaker jacks in parallel from one amp channel/output?

2. Do the SpeakON jack panels that I put in the wall have to be inside electrical boxes, or can they just be open to the inside of the wall? I realized that the bottom 2-3' of the wall isn't drywall/sheetrock, it's plywood -- which means if I don't need a box on the backside, I could use those Penn-Elcom cabinet dishes and just screw them directly into the plywood. That would also eliminate the need to drill/punch holes, since the dishes come ready to mount panel jacks.

[Brad Weber]

Originally Posted by mjl5007

True enough, but in this case yes, I do work for free (being a volunteer and all). But, I'm an engineer and this kind of thing (figuring out all the parts I need, then putting them together to build something) is highly enjoyable to me, so it's a win-win for everyone

There was just a discussion about this very issue elsewhere and it was pointed out that there is a difference between cost and value. Every minute you spend on this project is potentially a minute away from friends, family, work or other volunteer efforts and the brings up two related issues.

One is what is the value of that time to you and the church? Even if there is no associated dollar cost, your time and expertise represent a value. Could you offer or gain greater value investing that effort elsewhere? Is the value of your investment required, not the cost, justified?

The other is whether it might establish a precedent that any similar potential cost savings justified your investing a similar amount of your time, tools and skills and if it would be assumed that you would do so. If it could save some dollar amount elsewhere should the church assume you would invest your effort there as well?

If you want to do this for your personal enjoyment or because you feel it is part of your serving then those are great justification to invest the time and effort, but unless you can account for a fair value for the time and skills you'd be investing and still have it come out ahead financially, then it is probably best to not get caught up in the concept that the justification is the cost savings.

[BrianM]

A few cautions, from experience.

Seriously consider Brad's suggestion to put a screw cover metal box(often referred to as a Hoffman box) with terminal strips inside. It could be less expensive and DRASTICALLY reduces the odds that someone will unintentionally mis connect the wall to amp jumpers, or not get one of the Speakons fully locked and cause an intermittent connection. Six cables with six identical connectors at each end provides plenty of chances to goof.

Stainless steel is fairly abrasive and will ruin the large drillbits in short order. Plate makers like ProCo use a press punch instead. NEVER hold the plate in your hand when drilling. Not even to just "get the burrs off". I have been witness to several E.R. Trips because of the extremely sharp edges of the metal plates and a "catch" of the drillbit.

If you choose to use nylon plates a better connector choice would be the NL4MPR. It is round and has 4 fasteners to better support the jack in the relatively weak plate.