Car Audio: 2-ohm vs. 4-ohm speakers

[MR.MAGOO]

My car came with a basic no frills generic junk audio system, the head unit is probably under 20 watts power, more like under 15. One of the two rear deck speakers started sounding scratchy so I decided to replace them both. Without much thought I bought a pair of Rockford-Fosgate Punch (4-ohm). After ripping out the rear deck (The idiots who designed this car made it that way!), I discovered the El-Cheepo brand speakers were 2-ohm. Now I'm wondering if I've been a real idiot in replacing 2-ohm with 4-ohm speakers! Will my car catch fire?

 

[TLS Guy]

My car came with a basic no frills generic junk audio system, the head unit is probably under 20 watts power, more like under 15. One of the two rear deck speakers started sounding scratchy so I decided to replace them both. Without much thought I bought a pair of Rockford-Fosgate Punch (4-ohm). After ripping out the rear deck (The idiots who designed this car made it that way!), I discovered the El-Cheepo brand speakers were 2-ohm. Now I'm wondering if I've been a real idiot in replacing 2-ohm with 4-ohm speakers! Will my car catch fire?

No, your car will not catch fire, but the power available to the rear speakers has been halved.

Most likely your radio does not contain an inverter to increase voltage to the audio system. So if there is no inverter then the maximum rail voltage available to the rail voltage of the power transistors is 12 volts. So this is where the low impedance of the drivers is an advantage. Power delivered is the square of the voltage divided by the impedance. So for a two ohm speaker we get a theoretical maximum of 72 watts into the 2 ohm speakers, but 36 watts into 4 ohm ones. The actual power able to be delivered will be a bit less.

The bottom line is that you have lost 3db of output to your rear speakers.

 

[highfigh]

My car came with a basic no frills generic junk audio system, the head unit is probably under 20 watts power, more like under 15. One of the two rear deck speakers started sounding scratchy so I decided to replace them both. Without much thought I bought a pair of Rockford-Fosgate Punch (4-ohm). After ripping out the rear deck (The idiots who designed this car made it that way!), I discovered the El-Cheepo brand speakers were 2-ohm. Now I'm wondering if I've been a real idiot in replacing 2-ohm with 4-ohm speakers! Will my car catch fire?

What make/model of car?

 

[TLS Guy]

What make/model of car?

I was wondering that. You want to avoid that POS don't you? He is unlucky as a lot of car audio systems are excellent now and often better than people's home systems. Heck for most people now their car system is the best audio system they own!

 

[speakerman39]

Infinity still makes some 2 ohm car speakers. Best Buy sells them from what I can remember. We carried them for a while. Sounds like the OP has a GM vehicle with a factory amp. Chances are the OP has 6 1/2's, or 6X9's speakers in his rear deck.


Cheers,

Phil

 

[speakerman39]

The Infinity Kappas are 2 ohm speakers in various sizes. They are, however, a bit pricey. But, do they ever sound fantastic! Here is a link:

https://www.crutchfield.com/g_400/All-Car-Speakers.html?tp=105#&nvpair=FFBrand|Infinity


Please note that the Primus and/or Reference series do not have 2 ohm offerings. But, the Kappas do come in 2 ohm versions as does the components.


Cheers,

Phil

 

[highfigh]

I was wondering that. You want to avoid that POS don't you? He is unlucky as a lot of car audio systems are excellent now and often better than people's home systems. Heck for most people now their car system is the best audio system they own!

I installed car audio systems for a long time and I should have caught the Rockford reference to see the OP has a GM. Once the car makers realized that they were leaving millions of dollars on the table, they had someone like Rockford Fosgate design the audio section in their head units (GM), Infinity to supply speakers and amplifiers- Chrysler) or Bose to design the amplifiers and speakers (GM, Nissan, etc) or eventually someone like Harmon to sell the system as Mark Levinson/JBL. VW has used Dynaudio in some of the optional systems in their upper line cars. Much of the equipment sold before about '94 (GM started using Rockford-Fosgate around that time), the aftermarket car audio industry volume was around $8Billion.

One thing the newly improved system designs included was brand-specific speakers, with odd impedance. GM used 6 Ohm speakers for a long time and before the dawn of higher output with floating ground amplifiers, they didn't even use a second wire- they just connected the speaker - to a tab that was riveted to the speaker frame and used the car body as the common. I have seen 10, 6, 4 and 2 Ohm speakers and sometimes, the OEM head unit was completely unable to deal with anything lower than the original speakers.

If this is a Chrysler/Infinity system from the early-late-'90s, the amplifier might be under the package tray (also called the 'rear deck') where the speakers are mounted. Nissan sometimes used a similar location, but they also hid it somewhere to the side.

I agree- some OEM systems do sound pretty decent. At this point, I would only replace damaged speakers and even then, I don't want to jump through any hoops to do it. I have a Chevy Astro and one speaker's surround fell apart- I hated everything about replacing it. I might replace the head unit with something that has a Bluetooth receiver built in- the one that plugs into the lighter is very flaky, but it actually sounds fairly un-crappy.

 

[slipperybidness]

The Bose car audio systems that I have heard, actually sound pretty good.

The one place that Bose actually makes some sense.

I don't think it's really the aftermarket audio that the car companies are after, at this point. It's just all the navigation, car info screens, infotainment, etc. It really just makes a lot of sense to combine that into 1 package. Furthermore, the chip manufacturers provide canned solutions for all of these applications on a single board now.

 

[speakerman39]

I installed car audio systems for a long time and I should have caught the Rockford reference to see the OP has a GM. Once the car makers realized that they were leaving millions of dollars on the table, they had someone like Rockford Fosgate design the audio section in their head units (GM), Infinity to supply speakers and amplifiers- Chrysler) or Bose to design the amplifiers and speakers (GM, Nissan, etc) or eventually someone like Harmon to sell the system as Mark Levinson/JBL. VW has used Dynaudio in some of the optional systems in their upper line cars. Much of the equipment sold before about '94 (GM started using Rockford-Fosgate around that time), the aftermarket car audio industry volume was around $8Billion.

One thing the newly improved system designs included was brand-specific speakers, with odd impedance. GM used 6 Ohm speakers for a long time and before the dawn of higher output with floating ground amplifiers, they didn't even use a second wire- they just connected the speaker - to a tab that was riveted to the speaker frame and used the car body as the common. I have seen 10, 6, 4 and 2 Ohm speakers and sometimes, the OEM head unit was completely unable to deal with anything lower than the original speakers.

If this is a Chrysler/Infinity system from the early-late-'90s, the amplifier might be under the package tray (also called the 'rear deck') where the speakers are mounted. Nissan sometimes used a similar location, but they also hid it somewhere to the side.

I agree- some OEM systems do sound pretty decent. At this point, I would only replace damaged speakers and even then, I don't want to jump through any hoops to do it. I have a Chevy Astro and one speaker's surround fell apart- I hated everything about replacing it. I might replace the head unit with something that has a Bluetooth receiver built in- the one that plugs into the lighter is very flaky, but it actually sounds fairly un-crappy.

One of our installers pulled a set of Bose speakers out of a vehicle that was actually rated as 1 ohm. Not sure how that worked, but if I had to guess somehow the 1 ohm speakers were wired is series summing their impedances. I do not remember the specific vehicle, but it was a GM of some sorts. Never seen that before. Have seen lots of 2 ohm, 4 ohm, 6 ohm, and even 16 ohm on a few occasions.


Cheers,

Phil

 

[TLS Guy]

Infinity still makes some 2 ohm car speakers. Best Buy sells them from what I can remember. We carried them for a while. Sounds like the OP has a GM vehicle with a factory amp. Chances are the OP has 6 1/2's, or 6X9's speakers in his rear deck.


Cheers,

Phil

My GM Chevy Equinox has an excellent sound system. I think Pioneer did it. It is the LTZ model which has he Sat. Nav. head unit and the sound system with sub and lots of power. There must be an inverter as the vehicle has 120 volt AC outlets.

 

[speakerman39]

My GM Chevy Equinox has an excellent sound system. I think Pioneer did it. It is the LTZ model which has he Sat. Nav. head unit and the sound system with sub and lots of power. There must be an inverter as the vehicle has 120 volt AC outlets.

There has been some talk about moving from 12-volt to as high as 48-volt last time I read up on this. I used to sell inverters like they were candy. Things are really changing due to newer technologies in the automobile environment. Even my PT Cruiser has a decent factory sound system in it. It is amazing how much better factory sound systems has gotten.

AC outlets in a vehicle does not surprise me one bit. Many are used for game systems to entertain the kids/grand kids. Especially, on longer drives/trips. Having dual zone capability makes it work together very well. When it comes to head units, I prefer Pioneer!


Cheers,

Phil

 

[slipperybidness]

One of our installers pulled a set of Bose speakers out of a vehicle that was actually rated as 1 ohm. Not sure how that worked, but if I had to guess somehow the 1 ohm speakers were wired is series summing their impedances. I do not remember the specific vehicle, but it was a GM of some sorts. Never seen that before. Have seen lots of 2 ohm, 4 ohm, 6 ohm, and even 16 ohm on a few occasions.


Cheers,

Phil

I'm gonna guess that there may also be some active filtering going on there. It's a guess, TLS likely has a better guess than me.

My Nissan Murano has Bose, it is actually pretty decent. I already seen the forums on how to improve performance on the sub, but I'm not touching it until after the warranty period expires. Guaranteed, if I do mess with it and then have a warranty claim, they will try to use that to weasel out of a repair.

What I do like is that the amp and sub are one unit, and cleverly designed to fit in/around the spare tire in the rear floor panel.

 

[TLS Guy]

There has been some talk about moving from 12-volt to as high as 48-volt last time I read up on this. I used to sell inverters like they were candy. Things are really changing due to newer technologies in the automobile environment. Even my PT Cruiser has a decent factory sound system in it. It is amazing how much better factory sound systems has gotten.

AC outlets in a vehicle does not surprise me one bit. Many are used for game systems to entertain the kids/grand kids. Especially, on longer drives/trips. Having dual zone capability makes it work together very well. When it comes to head units, I prefer Pioneer!


Cheers,

Phil

Yes, we should move to 48 volts. For modern electric steering 12 volts is too low. As batteries get old the voltage can and does drop when suddenly engaging the electric steering, sending you into oncoming traffic. I already got the GM warning but no solution.

Well there is a solution according to BMW, and that is to install an expensive ICE battery which can produce high instantaneous current and change it every four years by the calendar. That is what I have done.

In studies voltages as low as 7 volts have been recorded at instances at the steering servo and controller. That makes it go haywire and is very dangerous.

We have had a number of unexplained head on crashes on rural roads in Minnesota in the recent past. I'm pretty sure I know the cause.

Before you install an battery ICE though, you must know that your voltage regulator is temperature compensated.

The funny thing was that GM could not tell me if my high frequency voltage regulator was temperature compensated or not. So I had to do my own tests to find out that it was!

 

[speakerman39]

I'm gonna guess that there may also be some active filtering going on there. It's a guess, TLS likely has a better guess than me.

My Nissan Murano has Bose, it is actually pretty decent. I already seen the forums on how to improve performance on the sub, but I'm not touching it until after the warranty period expires. Guaranteed, if I do mess with it and then have a warranty claim, they will try to use that to weasel out of a repair.

What I do like is that the amp and sub are one unit, and cleverly designed to fit in/around the spare tire in the rear floor panel.

Yeah some filtering no doubt. But what else could you do with a set of 1 ohm rated speakers? They certainly would not be wired in parallel lowering impedance down to 1/2 ohm. There must be a reason why 1 ohm speakers were used. Weirdest thing that I have ever seen. I even called the "Boss" and he was as dumbfounded as I was. Only seen that one time in all of the installs we did. Have seen a few 16-ohm speakers as well. Even that is a bit odd if you ask me.


Cheers,

Phil

 

[panteragstk]

My Durango has a JBL (Harmon) system and it sounds great. First vehicle I've ever owned that I feel doesn't need anything added to the sound system.

Worst car audio install I ever did was dash speakers in my parent's full size GMC van. Had to remove the ENTIRE dash to get to them. Then I had to remember where all the vacuum hoses went for the AC controls. Super fun that I had to do it twice because my dad blew the speakers. Who knew cheap 4x6 speakers wouldn't handle high volume? Well, I put a high pass filter on them the second time and they were fine.

I don't miss doing installs. Home or car. Too many screwy things can make something that should be easy anything but.

 

[highfigh]

One of our installers pulled a set of Bose speakers out of a vehicle that was actually rated as 1 ohm. Not sure how that worked, but if I had to guess somehow the 1 ohm speakers were wired is series summing their impedances. I do not remember the specific vehicle, but it was a GM of some sorts. Never seen that before. Have seen lots of 2 ohm, 4 ohm, 6 ohm, and even 16 ohm on a few occasions.


Cheers,

Phil

A 1 Ohm load is fine, as long as the amplifier is designed to handle it. However, I suspect the speaker had 1 Ohm DC resistance, not impedance. I don't remember seeing any that were marked as 1 Ohm, although I doubt I worked on all of the GM car models with Bose. Some of the Bose systems had the amplifier mounted to the tuned enclosure, along with the speaker.

 

[highfigh]

There has been some talk about moving from 12-volt to as high as 48-volt last time I read up on this. I used to sell inverters like they were candy. Things are really changing due to newer technologies in the automobile environment. Even my PT Cruiser has a decent factory sound system in it. It is amazing how much better factory sound systems has gotten.

AC outlets in a vehicle does not surprise me one bit. Many are used for game systems to entertain the kids/grand kids. Especially, on longer drives/trips. Having dual zone capability makes it work together very well. When it comes to head units, I prefer Pioneer!


Cheers,

Phil

After I stopped doing car audio, I moved into servicing boats and when I went to Mastercraft ski boat service training, we discussed the upcoming hybrid cars, which use a 48VDC system that has the starter mounted concentrically with the drive shaft. It requires less current to crank an engine at 48V than at 12V. The accessories were powered by one of the 12V batteries, with some of the early systems using four batteries, in series or a large battery with a 12V tap. This training session was in 1998.

 

[highfigh]

Yeah some filtering no doubt. But what else could you do with a set of 1 ohm rated speakers? They certainly would not be wired in parallel lowering impedance down to 1/2 ohm. There must be a reason why 1 ohm speakers were used. Weirdest thing that I have ever seen. I even called the "Boss" and he was as dumbfounded as I was. Only seen that one time in all of the installs we did. Have seen a few 16-ohm speakers as well. Even that is a bit odd if you ask me.

Cheers,

Phil

They use(s) proprietary load speakers to prevent people from using something other than theirs as replacements. It's their way of saying "MINE!". It's the same reason ford had that stupid football-shaped head unit in their Taurus- it took a while for Metra, Scosche and American International to make a kit so a standard DIN size head unit could be installed.

 

[MR.MAGOO]

What make/model of car?

2009 Nissan Sentra, back then a 'base' no-frills model. The sound system is generic, CD player, radio, 4 speakers, but does have an aux input for an iPod. I had toyed with the idea of replacing the entire sound system but I don't drive much, just that the rear speakers were shot so I replaced those. Today my rent went up $75 a month so I won't fritter money away on the car.

 

[speakerman39]

A 1 Ohm load is fine, as long as the amplifier is designed to handle it. However, I suspect the speaker had 1 Ohm DC resistance, not impedance. I don't remember seeing any that were marked as 1 Ohm, although I doubt I worked on all of the GM car models with Bose. Some of the Bose systems had the amplifier mounted to the tuned enclosure, along with the speaker.

My point about the 1 ohm stamped on the back of said speaker is that I have never seen that on any OEM speaker we pulled out of any vehicle. Since there were two of them, it was apparent to me that they must have been wired in series thus producing a 2 ohm load instead of parallel ending in a 1/2 ohm load. I would be very surprised if the over all load was at 1/2 ohm. Also have seen, on a few occasions, 10 ohm speakers. But, the 1 ohm blew my mind.


Cheers,

Phil