Speaker wire ga required?

dtfeld

dtfeld

Water Contrails
GOLD Sponsor
Jun 5, 2016
5,256
Milton, GA
Boat Info
410 Sundancer
2001
12" Axiom and 9" Axiom+ MFD
Engines
Cat 3126 V-Drives
One last detail for my stereo upgrade. What speaker wire gauge do I need?

Im running 4 x 7.7” in parallel @140W each, and a second pair of 8.8s on a separate channel at 150W RMS each. The Wire lengths are from 5-35 ft. Each speaker is 4 ohms.

I have 14ga on hand, but comparing it to the original speaker wire harness from Sea Ray, it looks a little “thin”. Keep in mind that was for a 50W RMS amp setup. Some online calculators say 10 ga or even 8 ga, which seems crazy.
 
I’m no audiophile and too many years of being around machines I have lost 50% oh my high frequency hearing. But I can tell you OEM audio wiring is notoriously under sized.
The issue is if you have two 8ohm in parallel you now have 4ohms impedance. You likely do want at least the 10 AWG.
Especially if you like it cranked up while the engines are running.
The smaller wire will sound mushy because the cones can’t react fast enough too much loss in the wiring.
 
The gauge for AC audio is based on wattage and distance, unlike DC, which is amperage and distance. So your calculators may be wrong due to the GIGO effect. Things that dont matter: impedance of individual speakers, their rated power handling and the quantity of speakers. Just the potential wattage from the amp and how far its traveling.

99 out of 100 boats, 14ga is plenty to service a pair of cabin/cockpit speakers in parallel on a single amp chnl. Keep in mind, that this is a scenario where the furthest away speaker jumps to the closest speaker, then on to the amp. In a case where each speaker makes a homerun to the amp and the parallel connection is made there, then you make your wire ga calc based on each speaker, not a pair. It rare occasion that we have super high output amps and/or very long runs, requiring large then 14ga. In many cases, 16ga is just right.
 
+1 on what @Wylie_Tunes posted.

I ran pvc jacketed 12ga knowing it was over kill. But I need to run new wires and there wasn't much difference in price.
 
ttmott said:
https://www.amazon.com/gp/product/B08QV4L55P/ref=ppx_yo_dt_b_asin_title_o05_s02?ie=UTF8&psc=1
What I used throughout the boat.
Click to expand...
I bought this exact wire in 14 ga. 12ga was 50% more, not sure I need it. I intend to home run all 6 speakers as to give the maximum flexibility to the configuration.

I may still upgrade to a 6 channel and have all 3 sets on their own zone. That would allow me to turn up the volumn, but keep the arch speakers a little lower as to not blast out our ears.

I have the 4 7.7s cut in, and need to work on the 8.8s and run the speaker wires to all six. Final project will be to run the new DC power cables, and move the amp to its new home.
 
car-speaker-subwoofer-diagram-chart-guide.png
 
If I have 2 x 4 ohm in parallel, or 2ohm load, 150 W, 35 ft. This says 10ga.

IMG_0955.png
 
dtfeld said:
If I have 2 x 4 ohm in parallel, or 2ohm load, 150 W, 35 ft. This says 10ga.

View attachment 145544
Click to expand...
In this calculator, is that 140 rms your amp's 2 ohm output or the speakers individual or summed RMS rating? Either way, 10ga for 140Ws of rms power is off the hook large! In a typical tower speaker run, we use 25-35 ft of cabling and 12ga for 400Wrms all day long.
 
Wylie_Tunes said:
In this calculator, is that 140 rms your amp's 2 ohm output or the speakers individual or summed RMS rating? Either way, 10ga for 140Ws of rms power is off the hook large! In a typical tower speaker run, we use 25-35 ft of cabling and 12ga for 400Wrms all day long.
Click to expand...
Correct. 140W each @2ohms into 4 speakers.

I think 14 ga out to be just fine.
 
It would never be possible use it in any of MY boats, but my outdoor stage sound kit includes a quartet of Peavey SUBcompact 18's driven by a pair of Crown XTI4002's... my stage leads from the amp rack to these subs are 50ft of 12awg... and while they'll run to the full 1200 with no issues, we rarely need to drive these more than 500w, as it's ultimately the speaker surface area, not the watts, that move the air, and it's air volume, not peak pressure, that fills an area. On the stage side, my instrument monitor is 200w, and I rarely see it break 60, and I'm not standing in it's pattern if it does. My vocal monitor is capable of 100, and it rarely breaks 35, but this is professional sound equipment, not automotive audio. It has been my general observation that the advertised power ratings of consumer equipment is incredibly overstated (and if it can actually REACH that rating, it occurs at an extremely high THD).

But if you're running four 4-ohm speakers in parallel, that's a 1-ohm load. Fed by 14awg wire, the greatest impedance in your circuit is neither xC nor xL, it's R... and that 14awg wire is likely the only thing protecting your amplifier from driving what is otherwise a dead short. If you decide to go thicker, your amplifier will likely last longer, and your audio performance will be better, if you go with a series-parallel circuit amidst your drivers.
 
The actual wiring is 2 speakers in parallel for both the left an rt channel. The Amp is capable of 280 per channel into a 2 Ohm load, hence the 140W per speaker. Picture of setup.

upload_2023-6-14_9-13-4.png
 
dtfeld said:
The actual wiring is 2 speakers in parallel for both the left an rt channel. The Amp is capable of 280 per channel into a 2 Ohm load, hence the 140W per speaker. Picture of setup.

View attachment 146027
Click to expand...

We need to call you diagram man now, I have never seen so many diagrams of a stereo system, very nice by the way.

I never really thought of putting speakers in parallel like this, I have always thought this is inviting distortion at higher volume levels. But apparently it is quite popular. Nice setup Dave.
 
Unfortunately, its taken about 20 iterations to find a way to make all this fit in a 20+ year old boat, and the only way to make sure I get the right pieces and parts is to plan it out before hand. It was a lot of measuring and re-measuring. Plus trying to keep the sound system working as all this happens.

I guess I could have stroked a check to somebody instead, but what's the fun in that?
 
dtfeld said:
... I guess I could have stroked a check to somebody instead, but what's the fun in that?
Click to expand...

Huh? Why, it comes out better like this and you can fix it if it breaks.
 
dtfeld said:
Unfortunately, its taken about 20 iterations to find a way to make all this fit in a 20+ year old boat, and the only way to make sure I get the right pieces and parts is to plan it out before hand. It was a lot of measuring and re-measuring. Plus trying to keep the sound system working as all this happens.

I guess I could have stroked a check to somebody instead, but what's the fun in that?
Click to expand...

Contract AVC to do it and you will write 3-4 checks!

Bennett
 
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