# 4 Gauge vs 8 Gauge sound quality ???



## duckymcse

Currently I am running 8 Gauge power wire with the JL HD750 amp and 12W7 subwoofer. Distant is about 7-8ft from battery to amp.
Everything work fine and sound great.
I wonder if I upgrade to 4 Gauge power wire, will the subwoofer sound ever better or there wouldn't be any sound different?


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## azngotskills

nope it wont unless you believe copper sounds different because of wire size


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## duckymcse

Thanks for the answer. 
Another question, is there any symptom I should be aware off running 8 Gauge wire with a 750W RMS amp?
I run it for 2 days already, so far everything seem fine. Not sure will there be any problem later on.



azngotskills said:


> nope it wont unless you believe copper sounds different because of wire size


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## Z3Sooner

The question is not about watts, it's about amperes, and the sub you are using has nothing to do with it. Different wire sizes are rated to handle current (amperes). What's the max current draw of the amp you're using? Find that and then go to this website:

Basic Car Audio Electronics

Go to the section on Wire and scoll down to the wire size/fuse size calculator. It will tell you everything you need to know. Also, just in case you haven't, FOLLOW THAT SITE'S GUIDLINES ON WIRE AND FUSES to the letter.

It's not about getting better SQ, it's about the difficulty of getting the smell of burnt human flesh out of the upholstery.



> Not sure will there be any problem later on.


Not to be overly dramatic, but you are talking about an electrical system that, if shorted, can generate THOUSANDS of degrees of heat in seconds if not properly sized and fused. "Not sure" can have serious consequences.


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## gijoe

The cable size doesn't play any sort of role in the quality of sound. The advantage to running a thicker power cable is that if you decide to add an amp or two later, then you can do so safely. The charts that you see are a good guide, but they are only a guide. The truth is, your system will usually be pulling much less current than their maximum. If your amp is fused with 2 30 amp fuses 60 amps is it's max, but it will be pulling much less than that 95% of the time. But, don't risk your safety by running tiny wire, especially over long distances. The 8 gauge that you have is fine for what you're running, but I'd be very careful if you add another amp. Switching to a bigger cable will be safer.


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## MarkZ

I've never heard of amps drawing so much current that they caused 8ga wire to catch fire. 

People use big wire so that they can get the most out of their amps. Will it yield an audible difference? Probably not. But some people get satisfaction knowing that 490w is available instead of 475w, you know?


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## Z3Sooner

Again, it's not about what will typically be the case. It's about what CAN happen and the consequences if it does. The maximum recommended current (based on 300 circular mils) for an 8ga. wire is 52 amps. Current draw for a typical class D 750W amp at clipping is 78 amps. Standards for proper wire size and fusing were developed for a reason.

8' of 4ga. cable costs $12.00. Pretty cheap insurance if you ask me.

By the way, the HD750 manual calls for 4ga. wire for anything over 6 feet. It also recommends a 60A fuse to protect the amp. Now, before you ask why they would recommend a 60A fuse for an amp that could draw 78A, it's because it takes time for a fuse to blow. Fuses rated for 60A will take several minutes to blow at amperages just above their rating.

It may be the conservative way to do it, but again, it's 12 bucks.


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## Z3Sooner

MarkZ said:


> I've never heard of amps drawing so much current that they caused 8ga wire to catch fire.
> 
> People use big wire so that they can get the most out of their amps. Will it yield an audible difference? Probably not. But some people get satisfaction knowing that 490w is available instead of 475w, you know?


Have you ever seen an amp short? It's not about what the sysem does when everything is working properly. It's about what happens when things don't work properly. JL recommends a 60A fuse. A 60A fuse is borderline for an 8ga. wire. It takes time for a fuse to blow and a wire can get very hot in that time.

Sure, the odds of something going wrong are slim, but the consequences are as high as total loss of the vehicle, and maybe worse. The standards are there for a reason. Follow industry standards and the manufacturer's recommendations.


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## MarkZ

Z3Sooner said:


> Again, it's not about what will typically be the case. It's about what CAN happen and the consequences if it does. The maximum recommended current (based on 300 circular mils) for an 8ga. wire is 52 amps. Current draw for a typical class D 750W amp at clipping is 78 amps. Standards for proper wire size and fusing were developed for a reason.


Ok, audio here. A 750w amp isn't going to draw 78 amps. It just isn't. The transformer (made of long lengths of very thin wire, btw) wouldn't handle it, and neither would the semiconductors. It may draw 78 amps transiently. But it won't draw that much continuous. And if you try to make it, you'll end up with other **** on fire before the 8ga wire will ever think about getting lukewarm.



> 8' of 4ga. cable costs $12.00. Pretty cheap insurance if you ask me.


A slow blow fuse is less than $1. And it's better insurance.



> Have you ever seen an amp short? It's not about what the sysem does when everything is working properly. It's about what happens when things don't work properly. JL recommends a 60A fuse. A 60A fuse is borderline for an 8ga. wire. It takes time for a fuse to blow and a wire can get very hot in that time.


So you're telling me that an 8ga wire will blow before a ~22ga. fuse will? How does that work?

Have you ever in your life seen a (fused) 8ga. wire get hot enough to melt the insulation?


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## duckymcse

Z3Sooner said:


> By the way, the HD750 manual calls for 4ga. wire for anything over 6 feet. It also recommends a 60A fuse to protect the amp. Now, before you ask why they would recommend a 60A fuse for an amp that could draw 78A, it's because it takes time for a fuse to blow. Fuses rated for 60A will take several minutes to blow at amperages just above their rating.


I'm using 80A fuse between the battery to the amp. It should be sufficient enough, right?


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## gijoe

duckymcse said:


> I'm using 80A fuse between the battery to the amp. It should be sufficient enough, right?


If the factory recommends a 60 amp fuse, you're going in the wrong direction. It's always ok to put a smaller fuse than rated, but you could be taking a chance running a bigger fuse.

Now just to clarify, does this amp have it's own fuses either internal or external? If so, the fuse you use on your power wire is to protect the wire, not the amp and should be sized appropriately. If there is no fuse on your amp, I'd recommend 1 fuse by the battery (to protect the wire) then another fuse right before the amp (to protect the amp).


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## t3sn4f2

MarkZ said:


> Ok, audio here. A 750w amp isn't going to draw 78 amps. It just isn't. The transformer (made of long lengths of very thin wire, btw) wouldn't handle it, and neither would the semiconductors. It may draw 78 amps transiently. But it won't draw that much continuous. And if you try to make it, you'll end up with other **** on fire before the 8ga wire will ever think about getting lukewarm.


Here's an article that shows why it might not pull that much transiently _with music_.

http://www.monstercable.com/mpc/stable/tech/A2403_Current_And_Efficiency.pdf


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## duckymcse

gijoe said:


> If the factory recommends a 60 amp fuse, you're going in the wrong direction. It's always ok to put a smaller fuse than rated, but you could be taking a chance running a bigger fuse.
> 
> Now just to clarify, does this amp have it's own fuses either internal or external? If so, the fuse you use on your power wire is to protect the wire, not the amp and should be sized appropriately. If there is no fuse on your amp, I'd recommend 1 fuse by the battery (to protect the wire) then another fuse right before the amp (to protect the amp).


I don't see any fuse from the JL HD750. What happen if I continue to run the 80amp fuse instead of the recommend 60amp fuse?


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## MarkZ

duckymcse said:


> I don't see any fuse from the JL HD750. What happen if I continue to run the 80amp fuse instead of the recommend 60amp fuse?


Probably nothing. Fuses are cheap though. Might as well replace the 80A with a 60A. You don't know how conservative they're being.


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## Z3Sooner

MarkZ said:


> Ok, audio here. A 750w amp isn't going to draw 78 amps. It just isn't. The transformer (made of long lengths of very thin wire, btw) wouldn't handle it, and neither would the semiconductors. It may draw 78 amps transiently. But it won't draw that much continuous. And if you try to make it, you'll end up with other **** on fire before the 8ga wire will ever think about getting lukewarm.
> 
> 
> 
> A slow blow fuse is less than $1. And it's better insurance.
> 
> 
> 
> So you're telling me that an 8ga wire will blow before a ~22ga. fuse will? How does that work?
> 
> Have you ever in your life seen a (fused) 8ga. wire get hot enough to melt the insulation?


First of all, the gage of the fuse is irrelevant. It's not copper. It's designed to handle a certain amount of amps before blowing. Here's a little exerpt from BCAE about fuses. 



> A fuse does not blow when the current reaches its rated current. It is designed to pass its rated current without opening. A fuse will take varying times to blow under different conditions. A fuse will pass significantly more than its rated current for a very short time. It may take 10 minutes or more to blow a fuse at 25% over its rated current. The table below is an example of the specifications for a slow blow fuse. You can see that a 20 amp fuse may pass 40 amps of current for as long as 5 minutes before blowing although it probably wouldn't take a full 5 minutes to blow. The times for other fuses will be slightly different.
> 
> %of amp rating Opening time
> 110% 4 hours minimum
> 135% 1 hour maximum
> 200% 5 minutes maximum


Yes, at 200% rated current for 5 minutes you could easily melt the insulation off the wire. Does it happen a lot? No. Most of the time you have a short in the circuit and you get a very fast spike which blows the fuse quickly. MOST of the time.

I'm sorry, but when you look at the consequences and you give me a choice between well established electrical engineering standards and "I've never seen it", I'm going to be conservative, spend 12 bucks on the wire AND a dollar on the fuse and know it's been done correctly and safely. Why screw around with it just because "you've never seen it".

As for the 80a fuse, spend the buck and get the fuse the manufacturer recommends. An HD750 is an expensive investment. Protect it.


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## duckymcse

Z3Sooner said:


> I'm sorry, but when you look at the consequences and you give me a choice between well established electrical engineering standards and "I've never seen it", I'm going to be conservative, spend 12 bucks on the wire AND a dollar on the fuse and know it's been done correctly and safely. Why screw around with it just because "you've never seen it".
> 
> As for the 80a fuse, spend the buck and get the fuse the manufacturer recommends. An HD750 is an expensive investment. Protect it.


Your point well taken. Thanks for the advice.


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## MarkZ

Z3Sooner said:


> First of all, the gage of the fuse is irrelevant. It's not copper. It's designed to handle a certain amount of amps before blowing. Here's a little exerpt from BCAE about fuses.


Everything the BCAE excerpt says about fuses applies also to wire. The temperature coefficients might be a little different, but the same physics apply.



> Yes, at 200% rated current for 5 minutes you could easily melt the insulation off the wire. Does it happen a lot? No. Most of the time you have a short in the circuit and you get a very fast spike which blows the fuse quickly. MOST of the time.


Read my question again. I asked you if you have ever seen hot _fused_ 8ga. wire. 200% rated current for 5 minutes means something is dreadfully wrong somewhere. If that happens, the 8ga. wire is the least of your problems. The fuse will pop before the 8ga wire gets hot, and before that happens the damned amplifier would probably ignite first. Trust me, if an 8ga. wire is getting hot, the relatively small traces on the board are getting much hotter much quicker.



> I'm sorry, but when you look at the consequences and you give me a choice between well established electrical engineering standards and "I've never seen it", I'm going to be conservative, spend 12 bucks on the wire AND a dollar on the fuse and know it's been done correctly and safely. Why screw around with it just because "you've never seen it".
> 
> As for the 80a fuse, spend the buck and get the fuse the manufacturer recommends. An HD750 is an expensive investment. Protect it.


Standards schmandards. What you're talking about is anything but "established". The reason I ask if you've seen it is because I know for a fact you haven't. What you're talking about is not realistic. Physics is a *****.


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## danssoslow

Would anyone here believe that it is perfectly legal and safe to run a residential or commercial A/C unit, fused at 40 amps, with a #12 wire?

Anyone care to guess why?


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## Oliver

Power Supply.....230/208 Volts 

My nephew saw a SUV with smoke rolling out of it after the guys jumped out at a light and opened the rear doors, they were pulling the wires out which were over fused [ no protection for wiring or amplifiers ].

Apparently the guy who wired it figured a bigger fuse wouldn't blow { he was right }.

I have seen the tips of 8 gauge wire burned black and would fall off when twisted between my fingers [ the sub was wired in parallel ], I just stripped the wire back and rewired the sub in series


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## danssoslow

a$$hole said:


> Power Supply.....230/208 Volts


If this is in reference to my question, not at all. The reason this is allowed is due to the fact that there are fail safes within the A/C unit to insure overcurrent protection. Breakers are sized for the maximum circuit ampacity, and the wire is sized for the minimum circuit ampacity, as stated on the manufacturer's nameplate.

So I'm figuring as long as the wire is ran safely, the amplifier has overcurrent protection, and the amp is fused per the amp manufacturer's recommendation, everything should be fine. Ambient temperature could be a real concern, being under a hood and all; but thermally protected Techflex could make this a non issue, couldn't it?


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## gijoe

danssoslow said:


> So I'm figuring as long as the wire is ran safely, the amplifier has overcurrent protection, and the amp is fused per the amp manufacturer's recommendation, everything should be fine. Ambient temperature could be a real concern, being under a hood and all; but thermally protected Techflex could make this a non issue, couldn't it?


As long as the wire is the appropriate size, yes, well usually. Not every amp out there has it's own fusing. Techflex isn't going to help much when a tiny wire heats up from the inside.


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## danssoslow

gijoe said:


> Techflex isn't going to help much when a tiny wire heats up from the inside.


I was thinking this stuff insulated its contents.


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## gijoe

danssoslow said:


> I was thinking this stuff insulated its contents.


Sure that'll work for keeping outside heat from destroying the wire, but that's usually not an issue anyway. If you're running too small gauge wire, the current is going to heat the wire up from the inside, wrapping something around the outside isn't going to do much.


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## MarkZ

An engine is going to heat up a wire. Current will not. This is audio, guys!


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## danssoslow

MarkZ said:


> An engine is going to heat up a wire. Current will not. This is audio, guys!


The engine heat is the only thing I figured the wire would need to be insulated from.

I have seen and felt for myself wire that has gotten hot due to an excessive current load; albeit in an alternating current circuit. I'm figuring that since the demands of a particular gauge, even in a dc circuit, are based on the current load, that excessive current can heat up the wire in a dc circuit also. 

I do, however, fail to believe that in this situation the #8 will get hot if the amp is working properly.


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## Oliver

duckymcse said:


> Currently I am running 8 Gauge power wire with the JL HD750 amp and 12W7 subwoofer. Distant is about 7-8ft from battery to amp.
> Everything work fine and sound great.
> I wonder if I upgrade to 4 Gauge power wire, will the subwoofer sound ever better or there wouldn't be any sound different?


Now let's discuss power wires improving sound  http://www.diymobileaudio.com/forum/diy-mobile-audio/64025-speaker-wire.html

Knit one . . . pearl two. . . < [ excellent hobby here . . . too ]


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## duckymcse

This is a follow up to my original question below. I got the answer through many hours of hard work and nearly heart attack 
I spend all day today rewiring my entire sound system. Here is what I found out.
1. Going from 8-gauge to 4-gauge DOES IMRPOVE sound quality. I can felt the bass sound louder and deeper from the subwoofer. The respond from the bass is better. The improvement in sound is not dramatic, but I felt the different. I change 8-gauge to 4-gauge for my Alpine PDX4.150 and the improvement is noticeable. I would say the improve in sound quality is about 20%. I use Monster Cable 4-gauge high end power wire, not sure if that make a different.
2. Now the most surprise to me is the audio cable. My previous installer use some decent audio cable running to my speakers and subwoofer. since I was so impress with the Monster Cable 4-gauge power wire, I decide to use some high end Monster cable(302 XLN for the 4 speakers and 402 XLN xtreme for the subwoofer) and the imrpove in sound was dramatic!!! I keep on say WOW and WOW as I listen to the music which I normally listen before. Everything sound so much better. Now, I am a believer in Monster Cable, sure they are expensive but it worth every penny once you hear the improvement in sound quality. I would say the improve in sound quality skyrocket to 50% better.
I almost got an heart attack rewiring my whole system. I didn't notice I had the ground wire from the battery connected. I normally have it disconnect when I work on my sound system. I tried connect the power wire to the amplifier and see a spark. I was thinking, old **** I hope I didn't kill the amplifier. I immediately plug back in the head unit and nothing. No power to the head unit and my 2 amplifier (all expensive equipment). I troubleshoot by checking all the fuse from my car and even tried with another head unit. The other head unit did power up but my 2 amplifier didn't. I decide to put back my original head unit and give it one more try and still doesn't power up. It suddenly work and it turn out the facelit was loose. Once the head unit power up, all my amplifier power up. I felt so stupid, but yet felt lucky and relief that I could had really kill my head unit and amplifier if I not careful when working on car audio system.




duckymcse said:


> Currently I am running 8 Gauge power wire with the JL HD750 amp and 12W7 subwoofer. Distant is about 7-8ft from battery to amp.
> Everything work fine and sound great.
> I wonder if I upgrade to 4 Gauge power wire, will the subwoofer sound ever better or there wouldn't be any sound different?


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## azngotskills

psycho-acoustics at its finest maybe  

Well im glad you like the "new" sound and your little mishap wasnt major!


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## duckymcse

azngotskills said:


> psycho-acoustics at its finest maybe
> 
> Well im glad you like the "new" sound and your little mishap wasnt major!


Thanks. It was a rollercoaster ride for me today. I spend so much money and time ever since I got into car audio couple of months ago. It's frustrating and yet fun especially when you doing it yourself manually.


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## goodstuff

MarkZ said:


> An engine is going to heat up a wire. Current will not. This is audio, guys!


It's only audio till something goes wrong. Then it's fire. Spend the 12 bucks or have a slight chance of fire? I'll spend the 12 bucks, thanks. Even if it was 50 it would be a no-brainer, no pun intended.


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## MarkZ

goodstuff said:


> It's only audio till something goes wrong. Then it's fire. Spend the 12 bucks or have a slight chance of fire? I'll spend the 12 bucks, thanks. Even if it was 50 it would be a no-brainer, no pun intended.


This is what fuses are for. If you think that upgrading from 8ga wire to 4ga wire is going to protect you from a short, then you have a lot to learn.

As I've pointed out repeatedly in this thread, NORMAL operation of the amplifier is not going to cause your 8ga wire to get hot or to ignite. If the amplifier fails, then either the amplifier's fuse or (if it doesn't have fuses) the fuse that you're supposed to install upstream of the wire will pop.

I can't believe people think that the wire upgrade means enhanced safety.


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## goodstuff

MarkZ said:


> I can't believe people think that the wire upgrade means enhanced safety.


Run some 32 ga then for all I care. I'm sure it's just as safe by that logic.


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## MarkZ

goodstuff said:


> Run some 32 ga then for all I care. I'm sure it's just as safe by that logic.


And if FUSED PROPERLY, it would be perfectly safe. It's retarded to try to bully people into using bigger wire by scaring them with imaginary safety concerns. God invented fuses for a reason.


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## goodstuff

MarkZ said:


> And if FUSED PROPERLY, it would be perfectly safe. It's retarded to try to bully people into using bigger wire by scaring them with imaginary safety concerns. God invented fuses for a reason.


I'm not bullying anyone. Just want people to be safe to the point of over kill. Which god invented fuses?


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