Wire size for long run to speakers
 

I am putting 4 speakers in an indoor riding arena. High fidelity is not important. The goal is to have a system that can be turned up loud without distortion.

The distance from the amplifier to the most remote speaker will be about 250 feet. The distance to the closest speaker will be about 50 feet.

Best Buy has rolls of large-gauge speaker wire, but it is pricey. Do I really need that fancy wire? This system is not for audiophiles. It is for people who ride to music and want to be able to hear it when their horses are far away from the speakers.

The heavier gauge the wire is, the more conductive it is. I would think you would need the really heavy stuff for a run of 250'. The power is going to dissipate more the longer the run is.

Just go to the hardware store and buy some 14/2 bulk wire... cheap and should do what you need just fine.

It's difficult for anyone to tell you what you need without some knowledge of the output of the amplifier. A 200W amp is going to need significantly heavier wire than a 50W amp.

250 feet is a looong way.............

I don't know much about the amplifier. It was a hand me down. I was thinking I would wire up these speakers and then go get another amplifier if need be. If I wind up going that route, I don't want the speaker wires to be a limiting factor.

250 foot section of lampcord would work... Its cheap, and you can get it at lowes...



How about Cat5?

What type of amp will be powering this system? For this long of a run you really need to use 70 volt line transformers.

If fidelity is of no concern, any wire can be used. The resistive losses in smaller guage wire will only limit the amout of power that reaches the load (speaker). For example, if the speaker is 8 ohms and the wire has 8 ohms of resistance (unlikely) the speaker will receive half of the power. The other half will be lost in the wire. Bigger wire=less resistance=less loss.

I hope you plan on using horns. Any direct radiating speaker would not be efficient enough for this application.

A "Cobraflex' is a very good speaker for this.

Regarding the wire... bigger the better. You could use 12/2 house wire.

I think that the crappy system that we have in the arena right now has 16 gauge wire and it is almost adequate, so you are probably right. Maybe I will go with 12 gauge just to make myself feel better about it.

At 250 feet, I'd use 12 AWG..........then you can be reasonably sure that a larger amp will not pose any issues.

Unless the amp is unstable into reactive loads. 250 feet of a wire is more than just series resistance.

Still, a 70 volt line system would be the best solution.

http://www.jblpro.com/pages/Distributed_Speaker_Systems_101_Rev_B.pdf

http://www.pearcable.com/sub_products_anjou_sc.htm

250 feet of that stuff will only run you about 150 grand. Do people really buy stuff like this?

Can you move the amp close to one set of speakers and then run each side in series?

That's an interesting thought. I don't have any flexibility on the location of the components. Equestrian concerns trump audio concerns, if you know what I mean.

Does running each side in series mean that I only have one pair of wires for each side? I should read up on that.

Speaking of sides, there really is no need for stereo in this application. A mono system with all four speakers all putting out the same thing would probably be just as good. The only reason I have been thinking in terms of left and right is that is the way my hand-me-down amplifier works. Is there a simple way of playing stereo sources such as CDs and playing them in mono? Any disadvantage to doing something like that in this application?

Really? Holy crap.I have a friend whom I would describe as a semi-professional photographer. A few years back he was thinking of laying out a small fortune for a Hasselblad setup. He knew it was extravagant, but he didn't want to get a "lesser" system and then always be wondering whether his photos would be just a little bit sharper if he went for the really high end equipment. The big time audiophiles probably feel the same way. They don't want to have that nagging doubt about whether they have the absolute best system. But $600 a foot? Good grief.

BTW, the advent of digital photography has my photographer friend thinking in a different direction.

There are audio purists out there that will spend a few grand on speaker wire...but consider that each of the components in the system cost upwards of several grand, so the cost of esoteric speaker wire puts it in the "accessory" category in terms of budget.

Still, those setups are housed in "listening rooms", where the runs from component to speakers are relatively short...

I had a friend (who shall remain nameless) who did quite well in the "high-end" cable and interconnect business. While there are certainly differences to be heard between materials, I have found that I can make my own cables (and interconnects, for that matter) for a fraction of the cost of the brand-name stuff, and it's fun to "DIY" a cable. As a matter of fact, http://www.diyaudio.com/ and http://www.tnt-audio.com/ are really interesting sites. I intend to build a pair of these cables in time: http://www.tnt-audio.com/clinica/triple_t_e.html

The program speakers in the auditorium here at work are quad amped with a total of about +2000W a side. The amps specify a minimum of 16ga wire and we're using 12ga for a max of about 200'. You'll need to know the load capacity (impedence) of the amplifier and the rating in Ohms of your speakers to wire them correctly and properly load the amp.

14 ga for your application is probably OK. 70V will allow smaller gauge wire but create more expense with the transformers needed. Post the amp brand, model, specs if possible along with the speakers.

I will check that out this evening. I don't think the amp is anything special.

Yamaha's website says that the speakers are rated at 6 ohms. I have no idea how that matches up with the amp.

Wiring speakers in parallel yields lower impedence. In your case, 6+6 will equal a 3 Ohm load. Wiring them in series will add the load giving 12 Ohms. Your amp will probably be rated at some wattage at 8 Ohms and some greater wattage at 4 Ohm per channel if it's stereo. Some amps can also be bridged which changes things again... That's why I was looking for specs on the amp too.

If your amp has four outputs you should be fine. But if it doesn't, running the speakers in series is much easier on the amp.

First connect the plus terminal from one speaker to the minus terminal of another speaker. Connect the other two terminals like you would a normal speaker, ie., plus terminal on the speaker to the plus terminal on the amp, minus to minus. Do the same with the other two speakers.

Now you've effectively made a stereo system with two twelve ohm speakers. Much easier to drive.

In long runs like this it is best to avoid low impedances. By connecting all the speakers in series (at the amp) you would have a 24 ohm load. Resistive loses in the wire would be nil at that impedance.
To make up for lost current (P=I*E) bridge the power amp. By bridging the amp the peak voltage (E) doubles. Doubling the voltage=quad power.

Buy one 500 foot spool of 14ga single conductor wire. Run this from the amp location to the first spkr(#1) positive, from there connect #1 negative and run it to #2's positive. #2's neg to #3s pos. #3's neg to #4's pos. #4's negative will return to the amp completing the circuit. Use a 9 volt battery to "click" these two wires confirming the circuit is complete. When you touch the wires to the battery you should here a click. Same when disconnecting them. It may not be real loud so listen to each spkr carefully while someone is connecting the battery.

Place the amp in bridge mode and connect one wires to the amps positive termanals. Nothing is connected to the negative termanals of the bridged amp.

Thiis will be the cheapest solution and the amp will be very happy with this load.

I've done many large iinstalls and engineer sound for touring bands so, feel free to PM if you need help with this.

Remember, P=I^2*R. 14ga wire can easily handle 15a even over a fairly long length. At 24 ohms, that gives a power of 5400 watts.

In this case the current carrying capacity of the wire is unimportant. It's the resistance that is of concern. I believe 14ga to be somewhere around 0.5 ohms per hundred feet. Not much in a 24ohm circuit.

I'd be more worried about the acoustics of the arena. Reverberant fields wreak havoc on the intelligibility.

Kuan and Whiskey Dan have my head spinning now. I don't get electricity.

I looked at my amp. It is a Sony STR-DE197 stereo receiver. On the back it says it has 190 watts. It has 4 sets of speaker terminals - an "A" set of left and right, and a "B" set of left and right (total of 8 wire connectors on the back of the amp). Below the speaker connections it says "Impedence - Use 8-16 [ohms]", except it used the symbol for "ohm" instead of the word.

I have never heard of bridging an amp, so I did some googling on it. How do I know whether this amp is bridgeable?

What does that mean?

OK, Your Sony is not bridgable. Some pro PA amps combine the A&B channels (left and right) to make one big power amp.

Since the amp will only handle a minimum impedance of 8 ohms you will have to wire two speakers in series and hook them to the left channel "A" . Then the two remaining and connect them to the right channel "A".

The Sony you have is rated at 100 watts per channel into 8 ohms. I doubt that will be anywhere near enough power for this application.

How big is the arena? How loud is the ambient noise?

Most audio power amps have two channels labeled either A and B or left and right.
Audio signals (the voltage on the spkr wires) consist a of complex alternating current. One wire goes positive relative to the other wire, then it goes negative. (AC)
This is what makes the spkr cone move in and out. More voltage, they move further making more sound. Faster movement means a higher tone, higher AC frequency.
Some pro amps and car stereo amps allow you to "bridge' those two cahnnels to make one big amp instead of two smaller ones.
In bridged mode one channel (either the left or right) is fed a signal 180 degrees out of phase such that its output goes negative when the other (non inverted) channel goes positive during the alternating cycle. This creates twice the voltage if you connect to the two positive terminals. Twice the voltage equals four times as much power (provided the amp can supply the current).
Any amp can be bridged with a simple inverting circuit. However, very few amps can accually provide reliable power this way.

In your case its a moot point. Lets hope for the best. :eek:

1ea. RadioShack 2054, PA Amp. (~$90.00). Use the 70V output and:
4ea. RadioShack 70VTR Transformers (~$60.00ttl) Run 14/2 lamp cord from Home Depot to: 4ea. RadioShack 1445 Outdoor Powerhorns (~$140.00ttl) I’m thinking the wire was somewhere around $160.00. Get 2ea. RadioShack Dynamic Microphones (~$30.00ttl) So your son (and his cousin) can yell at your daughter “You’re gone!!” when she knocks over a barrel running mid/high teens at age10. (a little brag there…sorry;))
You'll also need about $30.00 in zip-ties.

You’ll need a $6.00 1/8”-to- RCA adapter cable so the kids can just bring out their iPod or portable CD player and plug them in and leave the nice stereo gear with the $50.00 per foot monster cable in the house where it should be.

The amp has 100Hz, 1kHz and 8kHz tone controls to add some lows and cut back the highs you’ll have with the horns.

No – It’s not stereo. But it’s a riding arena for God’s sake. Not a concert hall.

But that’s just me.
You guys with the high-powered calculators and more hi-tech audio system brains than I’ll ever have can probably come up with something really cool to put into a filthy dirty high humidity bug infested occasionally rodent visited (indoor, or not) environment, I’m sure. :rolleyes: :)

You will need bigger than 10 gauge wire for 250' if your speakers are 8 ohm impedence. See table in the article:

http://www.roger-russell.com/wire/wire.htm

One cheap alternative is Romex. Great stuff if you are wiring a house for sound. A tad hard to bend but not impossible.

You can bridge it. On your amplifier you have two left channel outputs, output one and output two, each with one positive and negative terminal.

On the left side, get a wire and connect the plus from output one to the minus from output two.

+
-
\ <--- wire
/
+
-

Since your amp has 4 outputs already, before you go crazy with fancy hookups and buying a bunch of peripheral stuff or different amplifiers, just buy some 14ga zip cord or some 14-2 w/o a ground and run it, one output to each speaker. If it's not loud enough without distorting, you'll probably have to look into a bigger amp. Just make sure the speakers have the capacity to match the amp.

I'm sure the articles specifying larger wire are technically correct but in my practical, day to day experience, I think you should be fine with something a little smaller.

You can't bridge an amp off the speaker outputs. All that does is change the speaker load on the same channel. The amplifier has to support bridging and someone said this one does not.

250' is huge, the resistance loss is not insignificant and in this arena the volume levels will need to be high. Plus the resistance will change due to temperature, etc. The guy will probably end up needing a bigger amp if he sees distortion. Hopefully he won't throw a lot of unneeded money at the hardware.

I am not an electrical engineer, but anybody recommending anything like zip cord is nuts.

Unfortunately, those two negative terminals are tied together inside the box.
So, only the bottom chan in your sketch will be connected.

I'm sure he'll figure it out and get sound out of the thing. For a little while. :eek:

There are a lot kinder ways to disagree with someone without calling them nuts...

Probably 90% of the speaker wire sold in stores is zip cord. I have it run all through my house and I've pulled it out of old installs here at work when we demo them to prep for new systems. I've never seen it fail despite being in use for close to 30 years in some cases. However, we always replace any zip with plenum rated, twisted speaker cable of the appropriate gauge for the job because of corporate fire safety regulations.

I suggested this not as an off-hand comment but as a cost-effective solution that's adequate for the job.

As for your amp, IIRC, even though it has 4 outputs, some amps won't allow both sets to be active at the same time due to impedence constraints. If you find this to be true, connect them as suggested by Kuan in post 20...

The ring is 200 feet by 70 feet. The only ambient noise is the sound of the horse and rider. The Sony receiver is almost adequate even with the 2 ratty old speakers we are using now. My plan is to hook up the new speakers, see how it is, and then get a bigger amp if need be.

I will give that a try. It seems counterintuitive that increasing the impedance of the speaker combination will put less load on the amp, but there is a lot about electricity that seems counterintuitive to me.

Thanks to everyone for their comments. There's a lot of food for thought here.

Is mid/high teens a fast time? We don't have much barrel racing around us.

My wife would be jealous of your daughter. Her parents wouldn't let her ride until she was 10. She was hooked immediately. Now, 37 years later, she rides all day, every day. Totally hardcore.

You're right, it does seem counter-intuitive about the resistance in a parallel circuit. If you forget for a moment that you're dealing with audio and think about a simple circuit, if you have a resistor in the circuit, it provides a certain level of resistance. Adding additional resistors in parallel to the first one actually LOWERS the resistance in the circuit even though you're adding more resistors. This is because each additional resistor adds another path for the current to take and lowers the overall resistance.

Ideally you want zero resistance as ANY resistance is a loss of power.

The speakers has a 6 ohm "impedance". Although it may measure 6 ohms of resistance when tested with an ohm meter which uses DC not AC.

Speaker impedances can be all over the place due to voice coil inductance, crossover reactive components... very complex.

In this case, just use the single conductor wire and wire two in series tied to Left and the other two tied to Right channel. Safe, cheapest solution with least wasted power.

Is that the same way that Kuan recommended?

As I understand it, for the left channel, I will go from the positive terminal on the amp's left channel to the positive on speaker 1, then from the negative on speaker 1 to the positive on speaker 2, and then from the negative on speaker 2 to the negative on the amp's left channel.

Then I do the same thing on the right.

Is that correct?

Correct.

I believe you stated the spkrs were 6 ohms so, this will give you 12 ohms .
The Sony will be very happy with this load and should put out around 65-70 watts at that impedance.

Go to Lowes, Depot or better yet a small electric supply house and get a big spool of 14ga stranded wire. Be sure to mark the ends as you will end up with four identical looking wires at the amp.

I tried a few experiments with my speakers. First I tried it with the 4 speakers hooked in parallel (2 lefts in parallel with each other and 2 rights in parallel with each other). Then I tried it with each side hooked in series (2 lefts in series with each other and 2 rights in series with each other).

I think it was louder in parallel, although maybe not as clean. Was the parallel hookup louder because my poor little 100 Watt amp was in the process of burning itself up?

Sure, parallel might seem louder. Just watch the Sony for magic smoke.

That's what I'm thinking. I am going to hook it up in series and then see whether I need a bigger amp. It's already louder with these new speakers than it was with the old ones, but an amp with more oomf is probably in order

I've also concluded that a mono system makes the most sense, but I am still unclear about how to make stereo sources (primarily a cd player and xm radio) play in mono.

If you end up with a mono amp, you can use this:

http://cgi.ebay.com/Radio-Design-Labs-ST-MX3-Line-Level-Amplifier_W0QQitemZ270188619601QQihZ017QQcategoryZ23785QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

To properly combine stereo signals into mono. You shouldn't "Y" signals together.

Another choice is to find a TOA 924 MKII with a U-13 stereo input module. It's a mono amp that puts out 240W and can drive low OHM loads or 70V if you choose to go that route in the future.

Two Y cables will work fine.