We’re often asked the question “what is better, a 2ohm or 4ohm subwoofer?” To answer that question, we’ll need to start by asking what’s the difference between a 2ohm subwoofer and 4ohm subwoofer?
Technically, they are different in only a few areas and that is:
- How much they cost.
- How much resistance one can get.
- How much power will pass through your subwoofers.
- How much dB (logarithmic unit to measure acoustics) they can produce.
2ohm
When picking subwoofers, you’ll look at the ohm, the SI unit of electrical resistance, this indicates to you the amount of power that the subwoofer will be able to hold and the amount of power it can transform into sound.
A subwoofer with a lower electrical resistance produces a louder sound than one with a high electrical resistance, which means that 2ohm subwoofers are louder than 4ohm ones.
Although louder, 2 ohm subwoofers are also more likely to produce a poorer quality of sound due to its’ power consumption.
4ohm
4 ohm subwoofers will have a higher electrical resistance, use way less energy and will, therefore, last longer than subwoofers with lower resistance.
They also produce less sound in comparison to the 2 ohm ones. However, the sound produced could be described as being more compact so the sound you get from it is a much better quality than the 2ohm subwoofers but not so much as to be easily noticed.
Depending on the brand of the subwoofer you choose to purchase, the price could range between $20 and $180.
What’s better, a 2ohm or 4ohm subwoofer?
The biggest difference is in their prices, but this also depends on the brand and size of subwoofers you choose. A 2ohm subwoofer would be pricier than a 4ohm subwoofer, a 2 ohm subwoofer would range between $50 and $200 depending on the brand you choose to purchase.
There is also a difference of about 2.5dB between a 2 ohm and a 4 ohm subwoofer which some may be able to notice while others may not.
The difference between 2 ohm and 4 ohm subwoofers is not great and they will produce a similar quality of sound if run in the same wattage. Watts and ohms are all part of a series of mathematical formulas that put them together such that when one of them changes in value, the other often does too.
A brief explanation taken from Crutchfield:
“Amplifiers provide the electrical pressure in a circuit; ohms measure the resistance, or load, against that pressure; and watts measure how much power is released as work. So, using one of those math formulas, an amplifier that provides 100 watts of power through a 4-ohm speaker, will produce 200 watts through a 2-ohm speaker, because it’s easier to push that reduced load.”
Q. What is the power difference between ohms? Let’s say 400 watts at 8 ohms, & you put a 4 ohm cabinet with it. What percentage of added power is there? 30%, 40%? Does it change with different ohms? ie: 16 to 8, 8 to 4, 4 to 2?
Thx Frank
is a boss elite 1500 watt
2ohm monoblock amp too much power for 1 10″ Memphis shallow 300watt sub
https://m.youtube.com/watch?v=omK1eyFqc08
Please refer this link he dyno tests it and shows the actual output. It’s real output at 2ohms is less than 300watts.
U can put any amp that’s more watts than the woofer just set your gains for the woofer’s rms and not the amps.. use a multimeter… and you’ll be fine
Depends on the ohm of the speaker but you’re always better off with an amplifier that over powers whatever subwoofers you have then under power amplifier, because then speakers will be asking for way too much. That’s how you fry an amplifier don’t forget to consider if your running multiple subs, you need to consider if they’re wired in series or not, and if they are dual voice coil or single voice coil
To many unknowns to give you the right answer. How many ohms are the sub and is it dual or single voice coil?
My guess is no it’s not to powerful… boss tends to lie on their wattage specs generally especially low budget brands… now big dummy math this math is especially true with most class A-B amplifiers due to the fact they are only about 50% efficient in power conversions… now check the amperage of the fuse on the side of the amp and multiply by 10, if more than one fuse add up total amount of amperage listed on each fuse then multiply by 10… this is the max current your amp will draw from your cars battery & alternator before it blows… so if you see or have a total amperage or fuse of “80 amps”…. Using what installers call “big dummy math…lol” (80 amps x10 = 800 watts) also this is Max Wattage Not RMS Wattage… now take your amplifiers lowest rated OHM handling “usually it’s either 4, 2 or 1 if it’s lowest spec rating says 2 ohms then you have an amp that will produce a power output of: 800 watts max power @ 2 ohms and now to get the rms power you take that number and divide it in half and you have rms power output… this is always what I would be concerned with when pairing speakers with amps
Total rated amperage of all the fuses (if more than one) x 10 = max wattage @ lowest listed ohm rating of your amp found on box or in manual… maybe even online ( 🤷♂️ big dummy math 🤷♂️ )… boss is the worst always lying about specs!
Believe it or not most amplifier makers are not including a built in fuse anymore but including a inline fuse holder to put inline a few inches away from the amp… personally i like the look of this but now the amp company’s can lie easier… need multimeters and oscilloscopes and amp dynos to test true specs
I have a single voice coil sub that is 4 ohms and 150 watts rms and 300 peak power, i am running it on a class a/b boss audio 4 channel 400w peak power 2 ohm amplifier, it seems to be a bit weak. Will running the 4 ohm single voice coil sub on a 2 ohm amp be related to my problem?
Amplifiers usually output power based on the impedance of the sub. So if the sub is 2ohms and the Amplifier is rated for 200watts if you connect a 4ohm sub it will output 100watts to the sub. But it is not an issue. There is only a problem if you connect a sub with lower ohms like 1 ohm, then the amp will start to heat up.
yes you need a 4 ohm speaker to a 4 ohm amp. 2 ohm speaker to a 2 ohm amp
The answer is not as simple as that. Is the amp 2 ohm or even 1 ohm stable?
No because 2ohm is the final load it can take off your woofer is svc it’s only going to require 4Ohm from the amp only way you can change the ohm is to add a speaker then it’ll either double up or lose half the resistance
Yes, your amp is only rated at 400w to push an easy 2ohms. Trying to push 4ohms you would need a 600w amp to provide your 150rms wattage rec by the speaker. But I would recommend a 4ohm amp instead of higher wattage amp
Your problem is your using a 4 channel amp to play one channel/sub.You need a monoblock amp even if you have a dual sub.
I upgraded a little I had anew planet audio head unit the bells and whistles are there great price so I got a Rovkford fosgate r600x5 and 4 6.5 165×3 way speakers here’s the catch It’s an old car had ok speakers so used a wire harness I think I’m going to have to run wire from the ampto the speakers think so
I would do it even in a new vehicle. The factory is going to use the cheapest wire they can that will operate the OEM system. I run atleast 14 gage wire from amp to all speakers. I have actually ran 18 gage to all doors in my Explorer…turned the system on and was very displeased with the sound . It sounded like half the music wasn’t even being played. Very odd. I did a little research and changed the wires out and installed 12 gage…turned system back on and was BLOWN AWAY at the clarity and sound coming from my vehicle…I could not believe the larger wire had such a positive affect on the speakers. I assumed that the wires were short runs that it would not make a difference so I tried the small 18 gage…I was wrong.
Always run your own wire from any amp.
I am looking to purchase a Rockford Fosgate T1500-1bd and 2 fosgate p312 not sure if I should go with 2ohm or 4 ohm subs? I will be putting this setup in a fox acoustics dqc 212-v box under the rear seat of my 2017 ram 1500 quad cab. Please help. I am also contemplating going with either (4) 6×9 for the doors and (2) 3.5″ for the dash. I was wanting to do infinity kappa series however a friend of mine said I should do fosgate power series any suggestions? These will be powered by a fosgate t400-4. Thanks for your time and effort in helping me resolve this audio build delema.
Match your final ohm load with you amp.
Does it make sense to drop (2) 6×9 kickers to two ohms unamplified?
No.Most head unit are 4ohm and you could burn it up.
Actually, from an engineering perspective the author is looking at it from the most basic of calculations. Having lower resistance isn’t always better nor is it louder. Most of the time units with extremely low load resistances are horribly inefficient with the audio signal that is supplied.
Many of the people that would be buying sub-woofers at 1 or 2 ohm would be of the sound pressure level (SPL) competitions and not go for quality. If you want to win competitions, SPL isn’t everything. Go with accuracy, keeping all speakers in phase and going for clarity. The more clear and articulate your audio is, you can hear it further away. That’s what turns heads, not just the boom-boom fuzz buckets that are SPL competitions for the most part.
What all of you need to understand about ohms that are listed on the speakers are for “direct current loads” or DC voltage, that is called “load resistance”. Now, what you need to know is what the “alternating current loads are across the operating frequency spectrum”, which is based on AC voltage (audio). AC resistance is called, “reactance”. Now, across the lowest of the low that your sub-woofer can output to the high of the highs, the reactance will vary greatly, it won’t be uniform across the spectrum. What can affect this reactance are many factors, wiring, type of wiring, gauge, what the metal wire is made of, the cladding (the covering of the wires), the termination of the wires, etc. There’s so damn many parameters that people never take into consideration that will have a great impact on your sound and clarity of the sub-woofers.
The reason why you need ultra clear and accurate sound in the sub-woofers is because that’s the part of the system that uses the most power. In order to move the stiff cones on many of these sub-woofers it takes quite a bit of audio power to find the sweet spot while driving them. Look for speakers that have a higher sensitivity as per Watt and the sensitivity across the operating spectrum, that too fluctuates with the reactance.
I hope this gives you all a lot more information to look up, rather than going with a speaker that has half the resistance; that’s just plain drivel. If your amp can’t do 1 or 2 ohms, don’t try it, it could very easily end badly for you.
The reason why manufacturers of speakers don’t want to post their reactance data is that is shows all the imperfections and down right inefficiencies of their products. If you know how to read all of that data, you can be much more informed buyer and put together the best system that will keep you happy not just during competitions but outside of them, too.
Thank you for your post, hope people appreciate your time to do so, was not looking for particular info .
Just saw your post.. I remember going hard with my kicker competition set up back in early 90’s.
Alpine amp / for alpine mods & highs
Balanced out great for sound and bass.
What should I buy Rockford fosgate p3d4 15 inch 4ohm or p3d4 15inch 2 ohm subwoofers for my car
I’ve got a pioneer avh 120bt head unit 4 skar 6 1/2′ 2 in door 2 rear deck 2 JBL tweeters and an skar 8′ sub in modified 10′ bazooka tube a 12′ power acoustic mofo sub in a custom built box. I have a 1000w pioneer 360×4 amp for 6 1/2′ a power acoustic 2300 razor to run the 2 subs and let the head unit 50w run the tweeters. I have power in head unit power to the amps power coming out the amps but NO SOUND in a 08 civic SI coupe any help be greatly appreciated.
Thanks for sharing great content. I got my solution
Hi, I am Steven Paul Your article “What is better 2ohm or 4ohm subwoofer?” is very helpful for me. It gave me a lot of new knowledge at the end of reading your article.Im also searching the information about subwoofer but after reading your article I got a lot of knowledge about this topic. Thanks!
I have a TARAMPS M.D 1200 watt amp 1ohm stable hooked up to a SKAR 12 EVL 1250RMS 2ohm 2500 max watt subwoofer. Should I be concerned about stressing either or? Where should I be comfortable setting my gain? Would it be bad to have the amp maxed out? Also seen the same amp push 1590 watts steady on dyno. Thanks
If your sub is 2ohm and your amp is 1ohm rated at 1200w then hooking them together will cut your wattage in half to 600w. So you should be fine maxing out the gain. I am only wondering if it’s not loud enough for you because your asking about maxing out the gain and your under powering the subwoofer when you can use two of those amps and be fine.
Just bought the evl 12 skar 2500 watts but I did 4ohm for thinking when I order the 2 speaker it was going to be 4ohm to but it’s not its 2ohm so now I have a 4ohm 12 and a 2ohm 12 will that cause a problem
I have a 3000 watt audio dynamics amp hooked to my 15 in American bass 2×4 ohm 3000w max power subwhoofer and I have the wires on my speaker positive to positive and negative to negative then to the amp and when I just turn my key on it will beat good but when I crank my truck up the amp goes off an on why is that