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GCT
06-21-2011, 05:17 AM
Hi

I have 2 questions:

1. I have a couple of 15" cabinets that have XLR outputs and they're borrowed so I don't want to add extra connectors. To put them in parallel I can either join them behind the cabs in some type of Y connection or run separate cables to the amp and use stacked banana plugs. Is there a simple/cheap/snap Y connector solution?

2. Is 1.5mm2 cross-section cable OK for 15 - 20m 600w subs or is 2.5mm2 ? Price of copper has gone up. What are the standard cable specs for different speaker wattage?

Thanks

GCT

loach71
06-21-2011, 07:04 AM
I would re-model the cabinet to a Neutrik SPEAKON panel mount connector and use Neutrik SPEAKON cable end connectors throughout the hi-level signal path. These connectors are purpose designed for speakers.... The other stuff is just a work-around.

GCT
06-21-2011, 09:56 AM
I know the speakons are good but they're not my cabinets to mod.

Eaulive
06-21-2011, 11:33 AM
XLR for speakers??? :crying::eek::dont-know:

Allanvh5150
06-21-2011, 01:07 PM
Hi, XLR connectors have been used for years as a speaker connector. 1.5mm copper cable will be adequate for what you need.

Allan.

grumpy
06-21-2011, 02:45 PM
yep. often 4(+) pin varieties.

macaroonie
06-21-2011, 04:54 PM
Neutric spec sheet shows a contact rating as 16A for 3 pin and 10A for 4 pin versions

http://docs-europe.electrocomponents.com/webdocs/002a/0900766b8002a46e.pdf

Eaulive
06-21-2011, 07:52 PM
yep. often 4(+) pin varieties.

I know 4 pins XLR are the standard for 12VDC power in portable video broadcast equipment since the 70s, but I didn't know for speakers.

What I often see on old speakers is something like this:
51777

Also 1/4 phone plugs but this is really bad.
I also saw some AC twist lock plugs used for speakers in the past.

GCT
06-23-2011, 05:15 AM
1.5mm copper cable will be adequate for what you need.

Allan.

Hi, Thanks
So we're OK up to 600w on 1.5mm2 ? What about 1200W for the 2x15" future mid range?
GCT

hjames
06-23-2011, 05:45 AM
Hi, Thanks
So we're OK up to 600w on 1.5mm2 ? What about 1200W for the 2x15" future mid range?
GCT
If you can't change out the XLR connectors for something more robust like Speakons, it will just have to do, won't it?

Eaulive
06-23-2011, 06:01 AM
Hi, Thanks
So we're OK up to 600w on 1.5mm2 ? What about 1200W for the 2x15" future mid range?
GCT

Basically, cable size has nothing to do with the power you plan to use, as most cables handle at least 300V.
The important consideration is length and load.

If you have a 2 ohms load, the cable loss will be far greater than with an 8 ohms load.

Look at this chart for guidance: http://www.yorkville.com/default.asp?p1=5&p2=27&p_id=84

GCT
06-25-2011, 01:02 AM
Thanks for all your help
GCT

Allanvh5150
06-25-2011, 04:25 AM
Basically, cable size has nothing to do with the power you plan to use, as most cables handle at least 300V.
The important consideration is length and load.

If you have a 2 ohms load, the cable loss will be far greater than with an 8 ohms load.

Look at this chart for guidance: http://www.yorkville.com/default.asp?p1=5&p2=27&p_id=84

Keep in mind though, it is the current carrying capability of the cable and not its insulation resistance. Power loss in a cable is I2R, to get more power to the speaker you need to use a bigger cable.

Allan.

Eaulive
06-25-2011, 07:27 AM
Keep in mind though, it is the current carrying capability of the cable and not its insulation resistance. Power loss in a cable is I2R, to get more power to the speaker you need to use a bigger cable.

Allan.

What I mean is that the cable size issue is the same whether you use 5 Watts or 5000 Watts, the loss will be the same.

Allanvh5150
06-25-2011, 02:35 PM
What I mean is that the cable size issue is the same whether you use 5 Watts or 5000 Watts, the loss will be the same.

hmmmmmmmmmmmm.....ya lost me.

JuniorJBL
06-26-2011, 07:06 AM
What I mean is that the cable size issue is the same whether you use 5 Watts or 5000 Watts, the loss will be the same.

Longer run=more voltage drop
Longer run biger cable:dont-know:

Ruediger
06-26-2011, 11:09 AM
The total Q of the speaker will be compromised, that is the worst influence of too thin a cable.

Ruediger

GCT
06-26-2011, 11:27 PM
So practically, keep the cables as short and as thick as possible.

So what adverse effects occur in practice as the cable resistance increases?

GCT

Allanvh5150
06-27-2011, 02:25 AM
So practically, keep the cables as short and as thick as possible.

So what adverse effects occur in practice as the cable resistance increases?

GCT

Here is an easy way to think of it. For example: If your amplifier is 100 watts, Speaker is 8 ohms and the cable resistance is 2 ohms (example), power into the speaker will be 80 watts, power lost in the cable will be 20 watts. If the speaker is 4 ohms, power into the speaker will be 66.66 watts, power lost in the cable is 33.33 watts. If the speaker is 2 ohms, power to the speaker will be 50 watts, power lost in the cable is 50 watts.

This is a seriously bad cable of course, just to show the power loss. Basically, more copper = less power loss. 1.5mm2 will do for most speaker loads. However, on high power you may want to go to 2.5mm2.

Allan.

GCT
06-27-2011, 05:36 AM
OK Cheers.
The price of copper has gone up a lot. I will compare prices and measure the resistance of a few bits of cable to see what typical power loss I can expect.

GCT

Guy in WNY
06-27-2011, 11:32 AM
For wire gauge resistance charts. They are out there.
FYI, for RF coax cable, we look up the velocity factor and lose per 100 feet of cable (in dB) to select the right one for the job.
Shielding is always important also.

Eaulive
06-27-2011, 08:16 PM
Here is an easy way to think of it. For example: If your amplifier is 100 watts, Speaker is 8 ohms and the cable resistance is 2 ohms (example), power into the speaker will be 80 watts, power lost in the cable will be 20 watts.

Which means 20% loss, 0.97dB


What I mean is that the cable size issue is the same whether you use 5 Watts or 5000 Watts, the loss will be the same.


hmmmmmmmmmmmm.....ya lost me.

With you same example, if your amplifier power is 1000W, you get 800W to the speaker and you lose 200W, 20% loss, 0.97dB.
If your amplifier is 10 000W, you lose 2000W, still 20% and 0.97dB
If your amplifier is 1W, you lose 0.2W, again 20% and 0.97dB.

You don't see a pattern emerging here?

If you want to be picky, your amplifier rated 100W at 8 ohms will give you only 80W if you connect the same 8 ohms load through a 2 ohms cable (10 ohms total), which means that you will get only 64W at the speaker.
Now this is a 36% loss, a 1.94dB drop.

But still, loss is not related to amplifier power.

Allanvh5150
06-27-2011, 10:08 PM
If you want to be picky, your amplifier rated 100W at 8 ohms will give you only 80W if you connect the same 8 ohms load through a 2 ohms cable (10 ohms total), which means that you will get only 64W at the speaker.
Now this is a 36% loss, a 1.94dB drop.

But still, loss is not related to amplifier power.

Hmmmmm, I did not say the amplifier was rated into 8 Ohms. What I did say was that the amplifier was supplying 100watts to the load under all load conditions. As I said, Power loss in a cable is calculated with IxIxR. The more current through the cable, the more power is lost in that cable. As for how many db are lost, I was using a measurement that everyone here understands.

Allan.

subwoof
07-03-2011, 04:59 AM
The plating and THIN metal of XLR connectors means they will arc and burn on high current spikes. Then they are shot. Once.

Same for the 1/4" plugs. The chromium plating would actually act as a diode and half-wave the signal sometimes. Ever notice the high-end guitar and telephone company models are plain brass???

Back in the day when a 75 watt amp was plenty for a small PA ( or guitar rig ), these low signal level jacks/plugs would work in a pinch. Use today's large amplifiers and you are asking for problems.

Tell your friend that XLR's are the wrong connector.

Allanvh5150
07-03-2011, 01:46 PM
The plating and THIN metal of XLR connectors means they will arc and burn on high current spikes. Then they are shot. Once.

Same for the 1/4" plugs. The chromium plating would actually act as a diode and half-wave the signal sometimes. Ever notice the high-end guitar and telephone company models are plain brass???

Back in the day when a 75 watt amp was plenty for a small PA ( or guitar rig ), these low signal level jacks/plugs would work in a pinch. Use today's large amplifiers and you are asking for problems.

Tell your friend that XLR's are the wrong connector.

Generally Subwoof, I would have to agree with you. Having said that I have a bunch of old Perreaux Amplifiers, including 5150 and 8000b, they all have XLR connectors, they are all 25+ years old and all the speaker connectors perform perfectly. Although the XLR's are rated at a particular current, the systems never operate in this way. Although now superceded by speakons, the are still a pretty damned good connector.

Allan.

P.S. some speakons abd XLR's of asian origin are very dubious at best. Use a good brand.

GCT
08-09-2011, 01:20 PM
In the end we used XLRs on the cabs and bananas on the amps. When the cables were made I realized that our ECLER amp had different post spacing. Stereo banana only fits in bridge ( between the 2 reds)and not stereo (red / black) and written on the back of the amp it says no 4 ohm bridge.lol