Arena stereo speakers - speaker wire length?

[weedsportpete]

Does anyone have music in their arena? We have a cheap boom box in the barn, and are thinking of upgrading to a stereo which can have two sets of speakers, and putting a set of speakers in the arena.

Based on fuzzy memories of sound quality, and recent experience in electrical wiring, I know that there is current loss with longer wire..

Can anyone comment on the practicality of running speaker wire in an arena? We have a feed room just inside the common wall between the arena and barn where we could put a stereo (the stereo is 50 amp, and is about 20 years old; speaker outputs are 8 ohm). The arena is 160 feet long and 60 feet wide, and I'm thinking about putting the speakers in the middle of the arena, so adding in all the turns, it would be about 100 to 140 feet of paired wire for each speaker.

Is this asking too much from a stereo? Also, would we have to turn up the volume to make up for the current loss? So the speakers in the barn would be way too loud?

Thanks

[Pat]

Pete, You will need to upsize the wire to compensate for the length of the run otherwise you will likely have more volume from the speakers with short wires. It will not be a massive variance but could be bothersome if you used too fine of a wire size for the long run. Our hearing is a log not linear response in volume so that helps compensate some. Your 50 Watt unit... is that 50W per chanel or for both (25 each), or 50 W consumed out of the wall? (descending order of desirability) The first might work, the second would be iffy, and the last might not do so good.

Another issue... is that 50 W IHFM or two tone sine test RMS rating or what? An arena is a large volume to ensonify with two low power speakers. The sound would probably be distributed much better if you would spring for 2 or more pairs of speakers rather than just one. This would allow a more uniform distribution. Otherwise due to the great variance in distance between the speaker and your ear as you move around will give a very uneven loudness. In this venue, you might be better off switching the unit to MONO if that is an option. Give it a try and compare while roaming around the arena not just standing in a "sweet spot." You can also "pad" the speakers with the shorter run, i.e. introduce some non inductive resistance in series to give the short run speakers the same disadvantage the long run speakers have and the volumes will be equalized (assuming speakers that have equal efficiencies.) If the two sets of speakers have different efficiencies, use the more efficient (louder) ones in the arena. You might want to add a little extra resistance to the short run speakers because even at the same volume level they will be percieved to be much louder because of the smaller volume of the space they are in.

In the "OLD DAYS" you could have gone to any Radio Shack and there would be at least one guy there who could have told you what to do and sold you a few bucks of components to do it with. Nowdays... GOOD LUCK! Oh there are still a lot of folks at Radio Shack stores who will tell you what to do, it is just that most don't realy know even if they are willing to pretend they do.

Hope this helps... If this didn't completely confuse you, just come back and I will try to finish the job!!!

P.S. I have often wondered just what sort of sport a weed sport is???

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[weedsportpete]

</font><blockquote><font class="small">In reply to:</font><hr />
<font color="red"> P.S. I have often wondered just what sort of sport a weed sport is???</font color>

[/ QUOTE ]
Its a contest to grow the most, tallest weeds in your pasture! I've won two years running..

Thanks for the info.. I understand what you mean about matching up the resistance. It may be easier to work with the wires in the barn than the wires in the arena.

I didn't remember right about the power; I did a search on google and discovered that it has 80 watts per channel, so that should help. When both sets of speakers are running it uses up to 32 ohms (or that is how I read the back of the stereo).

Maybe if I could get a good enough remote, I could mount it on a rafter in the middle of the arena and turn it on from there. I've got my lights plugged into outlets I wired up there so there is power available. The only problem that I see is the dust. We keep it watered in the summer and salted in the winter, but there is still dust.

PS Weedsport is named after the Weed brothers, who had a town originally named after them called Weed's Basin (on the old Erie Canal).

[Pat]

Pete, Thanks for the info on Weed Sport. So you get a bronzed (K-Mart goldtone spray painted) dandelion or something as a prize?

In electronics/audio engineering it is caled impedance matching. If you match the impedance of the sink (load) to that of the source, you maximixe power transfer efficiency and miimize distortion (some amps are sensitive to impedance match). Unmatched loads can reduce output and even pop overloads or cause automatic protection circuits in more sophisticated gear to cut back on power as the mismatch heats up the output stages.

Speakers hooked in series, the Ohms add. Speakers hooked in parallel, the equivalent Ohms is a tad more complex.

Series: Zt = Z1+Z2+...Zn

Parallel: Zt = 1/ (1/Z1 + 1/Z2 + 1/Z3 + ... 1/Zn)

Where Zt is total or equivalent impedance.

Two 8 Ohm speakers in parallel is a 4 Ohm load. Four 16 Ohm speakers in parallel would be 4 ohms.

Two 8 Ohm speakers in series would be 16 ohms.

You can parallel two 8 ohm speakers (4 Ohms) and put that pair in series with another parallel pair (another 4 Ohms) and get 8 Ohms as a total.

This sort of manipulation will allow you to use multiple speakers and not get to far away from the output impedance the amp "likes."

Cheaper speakers sometimes sound pretty good at lower volume levels. Multiple speakers at lower volume levels is superior to just a speaker or two that have to be turned way up. You end up with places that are uncomfortably loud and places where there isn't nearly enough volume. More speakers spread the sound more evenly and are more comfortable.

(Warning: THIS WILL BE ON THE MIDTERM!!!) [img]/forums/images/icons/grin.gif[/img]

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[bczoom]

Pete,

I can't keep up with the techincal stuff Pat is giving you but I'd like to throw in my 2 cents.

It's been a couple years since I bought anything, but Onkyo has receivers with greater current than most. These receivers should give you the distance you need. I have 2 of these units with speakers more than 50' away with no problems.

For speaker wire, I'd consider getting a roll of lamp cord wire. It's the exact thing as a heavy gauge speaker wire but at about 30% of the cost.

For speakers, you may want to consider an indoor/outdoor speaker. They can take all the dust, water...

[Pat]

Right on bczoom, lamp cord (AKA zip cord) is pretty good speaker wire. Just be sure in doing the cost comparison you are comparing equal wire gauges. Longer runs would be better served if you get at least 14 ga. (in wire smaller ga numbers is bigger wire and biger is better) Don't go for all the HYPE about low oxygen content copper or gold plated connectors and a bunch of other snake oil. While there is a grain of truth in some of the claims, in your application you will never know the difference even if you did an A-B comparison.


[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[muncybob]

Without a doubt you need the largest gauge possible, keep in mind you need to check and see what the terminals on both the amplifier and speakers will accept.....I bought 12 ga. recently only to discover that the volume control in the back room had a max ga. of 14! I've found Impact Acoustics to have decent quality wire at reasonable prices.

[Pat]

muncybob, I think you might have overstated the situation when you said <font color="red"> "Without a doubt you need the largest gauge possible"</font color>

Although even larger cables are POSSIBLE than say, 4-0, in general that would likely be a bit over the top. Even in house wiring larger is better, only to a point. Larger is less loss from less resistance but there is a point after which the performance increases are marginal and the costs are out of hand.

Once you have reduced the impedance of the wiring to an insignificant (or at least tolerable) fraction of the speaker's impedance, there is reduced incentive to go larger. That is why higher Ohm speakers (provided the signal source can efficiently drive them) can be better where there are long cabling runs.

An example: You have a long cable with 2 Ohms DC resistance and a speaker with 2 ohms impedance. In this instance 1/2 of the amplifier's output power will be expended heating the cable, not making sound at the speaker. This is 50% efficient at delivering power to the speaker. If the equipment could efficiently drive a 16 ohm speaker (some can and some can't, check the specs) then about 89% of the amps output would get to the speaker. With an 8 Ohm speaker you would get 80% of the power to the speaker. Of course with different assumptions in the resistance of the wires you will get different results but in all cases the lower Ohm speakers would be less efficient at receiving power. However some modern transformerless solid state outputs NEED low impedance speakers to enable them to deliver anywhere near there rated output.

With audio cable size, bigger is more efficient, not necessarily better. Better implies many underlying assumptions. At some point, increasing cable size does not result in noticeable improvements in performance and you have passed the point of diminishing returns.

Another point: you don't have to size the gauge of the cable run by what will fit on the terminals of the speaker or source. You can splice a short length of appropriately sized wire at the ends of the run that will easily accommodate the terminals. The increased resistance due to a few feet of say, 14 or 16 ga wire will be negligible, virtually immeasurable and certainly not audible. If you are a super purist, you can buy terminals to fit your large wire on one side and the connections on equipment/speakers on the other.

Power distribution efficiency isn't everything! Acoustic efficiency matters. Some speakers are way louder on 10 Watts than others might be on 50 Watts. If your speakers are more efficient, they may deliver more volume even if the wiring is suboptimal than giant wires going to less efficient speakers. Of similar effect is room acoustics and masking noise from the environment which deteriorates the signal to noise ratio and causes you to want (In the words of the mighty GURU Tim Taylor) MORE POWER!

[img]/forums/images/icons/smile.gif[/img] Patrick (who has trouble hearing the soft high notes anyway from too much time as a rock drummer, and big bore shooter with inadequate hearing protection)

[muncybob]

I guess I've always been a bit of a purist....hate splicing audio wiring...was never big on the connectors either...just seems to me the more times you add something to the audio carrier the more you will diminish the quality and maybe increase the resistence....but mainly I was just trying to say bigger gauge on longer runs will help the amp run somehwat cooler. Don't get me wrong, an audio expert I'm not, just looking at it from a logical view....you are probably much more versed in these things than I.....and since you probably are, can you tell me what the difference is in CL2 rated wire vs. CL3 rated....I take it that CL2 is residential and the other is commercial?? I'm about to run apprx 200 ft of wiring to a new addition(2 speaker pairs with 1 pair inside and the other pair exterior for tunes to throw horseshoes next year [img]/forums/images/icons/grin.gif[/img] , total of 200').....

[Pat]

http://www.crutchfieldadvisor.com/le...kers_wire.html

and similar pages might help you.

Nothing wrong about being a "purist" if it doesn't interfere with realistic progress. There is nothing inherently BAD about splicing a wire, audio or otherwise. RF signals can experience an impedance "BUMP" if you splice a transmission line but at audio frequencies you could not hear and likely not be able to measure any effect unless your splice was very poor quality indeed. Adding a 6 inch "tail" of smaller and more conveniently flexile wire to a large wire to accomodate a connection adds the same increase in resistance as if the original wire were a few feet longer, at most. NEGLIGIBLE.

There is a lot of snake oil hucksterism at play in the marketing of audio accessories, including wire. Tell the big lie often enough and it becomes the self evident truth! There is often a small nugget of truth to the claims but its applicability and scope is all to often lost on the reader of the advertisement. A lot of what passes for "insider info" among those who would see themselves as accolytes to the high priests of audio guruship, is mostly bunk.

For 200 ft of run I recommend at least 12 ga as a minimum. Are you running it inside of a finished wall? The claim to fame of CL3 wire is that it is UL rated for inside of a residential wall. It meets FIRE codes. It is FIRE SAFE. CL2 or CL3 doesn't guarantee any particular audio distribution excellence, just that it meets abrasion resistance requirements so it doesn't come apart when pulling it through the studs or whatever. It meets heat requirements, etc. So does ROMEX. Romex is solid copper while if you read the fine print some CL2 is steel core with copper coating. How does that apeal to you?

Here is a piece of advertisemet for SUBWOOFER CABLES...

<font color="red"> Cables are the weakest link in the chain, so be sure to buy the best quality you can afford. </font color> They were selling double shielded cables that promise to keep out noise even in tough situations. Of course, they are trying to boost sales of more expensive higher markup products. They do so by contributing to and perpetuating a pervasive ignorance of what actually is practical in audio electronics.

This is right up there with the funeral director/salesguy trying to upsell you from the damp proof casket to the MOISTURE PROOF casket with silk lining instead of satin so as not to chafe the loved one.

In hot rodding, if it won't go, CHROME IT! In audio, if you can't hear the difference, then make up a bunch of esoteric BS based loosely on facts that hardly engage the application and JUST TAKE THE MONEY!

I gota go... I need to take out all the worn out air in my tires and put some fresh new air in so it holds the car up better. [img]/forums/images/icons/wink.gif[/img]

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]