Wiring subwoofers with different ohm voice coils together

SkrillaPyles

CarAudio.com Newbie
I have a kenwood 9104d amp. I did some research on it and it says it does 900 rms at 2 ohms and is regulated down to a lil over 900 at 1 ohm .I had dual 12 punch p3s (2ohm) and wound up blowing 1 of them. my friend gave me a power acoustic gothic. It's a 4ohm dvc. I know it's not good to have subs that have different ohms. .. but since the amplifier is regulated at 1 ohm. So can I run the punch on left at 1 ohm and the gothic on the right at 2 ohm then they would be very close to receiving the same power
 
Thats a mono block amp. Its internally bridged with 4 outputs. All one channel. No left and right.

Running two different subwoofers causes cancelation issues let alone running two different resistance subwoofers. One will be getting more power than the other.
 
Thats a mono block amp. Its internally bridged with 4 outputs. All one channel. No left and right.

Running two different subwoofers causes cancelation issues let alone running two different resistance subwoofers. One will be getting more power than the other.
Yes I know that. How bout if I ran both speakers parallel. That you be 2+2+4+4=12 12÷2=6 then 6÷4=1.5 ohms, if the subs can withstand a 1 ohm load , how come I cant run a 1.5 ohm load?
 
Yes I know that. How bout if I ran both speakers parallel. That you be 2+2+4+4=12 12÷2=6 then 6÷4=1.5 ohms, if the subs can withstand a 1 ohm load , how come I cant run a 1.5 ohm load?
It's doable, but they subs won't get the same amount of power. If your amp is stable down to 1 ohm, then it doesn't care how you get there; it only cares about the load it sees at the speaker terminals.

Having said that, I don't know where you came up with that formula for calculating parallel loads. If all parallel branches are the same resistance, you can use the formula Rt = Rx / Rn ; Total resistance equals the value of each branch divided by the number of parallel branches. If each branch is a different resistance, then you use the formula Rt = 1/(1/R1 + 1/R2 + 1/R3 ....).

In your case you could technically use either formula, but let's go with the latter:
Rt = 1/(1/4 + 1/4 + 1/2 + 1/2);
Rt = 1/(6/4);
Rt = 2/3 ohm, or roughly 0.67 ohm, which is lower than your amp can handle.

Your best bet would be to wire the dual 2-ohm sub in series to create a 4-ohm load, then wire all three 4-ohm loads in parallel. Thereby, Rt = 4/3 = 1.33 ohms.

As stated by others, having two different subs or sub with different impedances will not give you ideal results, acoustically speaking, but if you wire them correctly, it is far from impossible.

Bear in mind, I'm just some guy on the internet, as is everyone else who provides advice in forums. The information I gave you is electrically correct, but follow it at your own risk. If you didn't know how to calculate total resistance, you might be better off either keeping it simple (get two of the same subs) or paying someone to do it for you.

On a side note: I don't know how running two subs in phase with eachother would create any cancellation. I would love to hear the theory behind it.

Hope that helps.
- Joe
 
It's doable, but they subs won't get the same amount of power. If your amp is stable down to 1 ohm, then it doesn't care how you get there; it only cares about the load it sees at the speaker terminals.

Having said that, I don't know where you came up with that formula for calculating parallel loads. If all parallel branches are the same resistance, you can use the formula Rt = Rx / Rn ; Total resistance equals the value of each branch divided by the number of parallel branches. If each branch is a different resistance, then you use the formula Rt = 1/(1/R1 + 1/R2 + 1/R3 ....).

In your case you could technically use either formula, but let's go with the latter:
Rt = 1/(1/4 + 1/4 + 1/2 + 1/2);
Rt = 1/(6/4);
Rt = 2/3 ohm, or roughly 0.67 ohm, which is lower than your amp can handle.

Your best bet would be to wire the dual 2-ohm sub in series to create a 4-ohm load, then wire all three 4-ohm loads in parallel. Thereby, Rt = 4/3 = 1.33 ohms.

As stated by others, having two different subs or sub with different impedances will not give you ideal results, acoustically speaking, but if you wire them correctly, it is far from impossible.

Bear in mind, I'm just some guy on the internet, as is everyone else who provides advice in forums. The information I gave you is electrically correct, but follow it at your own risk. If you didn't know how to calculate total resistance, you might be better off either keeping it simple (get two of the same subs) or paying someone to do it for you.

On a side note: I don't know how running two subs in phase with eachother would create any cancellation. I would love to hear the theory behind it.

Hope that helps.
- Joe
I know how to calculate the resistance if each voice coil is the same. But for some reason I was thinking you also had to divide it by # of subs as well then also using the wrong formula, I did not know how to do it with voice coils of seperate resistance. That's why I'm asking. I wasn't saying it like it was fact. I was asking a question about my math because it looked off and it was. as for the cancelation I was wondering about that too because I have already hooked them up in a parallel To my audiopipe ampi-1300. It didnt seem to have a problem with it. And sounded good
 
The different brands cause cancellation is real. It doesn’t happen in every case, but it does happen. It is basically because of a difference in response times of the cones.
Here is the over simplified version. Say you have two subs. One has a heavy cone, a 2 inch voice coil and a 30 oz magnet. And the second sub has a lighter cone, a 3 inch coil and a 100 oz magnet. Play a single drum beat. Sub 2 is going to move the cone quicker than sub 1. In fact, sub 2’s cone may be returning to rest while sub 1’s cone is still moving out. You end up with phase issues and cancellation.
 
Of course you can. The amp has no response to what is connected to it other than impedance. Wire the D2 in series for 4 on one output and the D4 parallel for 2 on the other. The p3 will see 1/3 of the power, the PA will see 2/3.
The amp doesn't have separate channels -- it's just two connections to the same channel so anything you connect to one output will be parallel to the other. Also -- subs don't "withstand" the load. They ARE the load.
Don't expect great sound quality, but it will give you some bass until you can get a proper matching pair.

You might have better results just running the Pwr Ac at 2 ohms.
 
Last edited:
The different brands cause cancellation is real. It doesn’t happen in every case, but it does happen. It is basically because of a difference in response times of the cones.
Here is the over simplified version. Say you have two subs. One has a heavy cone, a 2 inch voice coil and a 30 oz magnet. And the second sub has a lighter cone, a 3 inch coil and a 100 oz magnet. Play a single drum beat. Sub 2 is going to move the cone quicker than sub 1. In fact, sub 2’s cone may be returning to rest while sub 1’s cone is still moving out. You end up with phase issues and cancellation.
I'm having a tough time with your logic here. I understand the theory you're running with. However, I would like to see an experiment with numbers to back that theory up.
Given the theory that cones move at different rates, they still have to react to the sine wave being delivered to the voice coil. If the cone reacts any fraction of a second behind the signal getting to its terminals, the cone will eventually either catch up with the signal or move in the complete wrong direction. I think it will catch up and move on-point with the signal. So that leaves a split second where they subs might be out of phase (unnoticably).
Also, given your theory is accurate, your two subs will always be a different distance from you, so you could argue that the different distances could actually make your subs sound louder by being ever-so-slightly out of phase. The sound waves/air vibrations have to travel from the speaker to any given point, so maybe the air vibrations would be more in sync by the time they get to the listener/meter.

Playing devil's advocate here, but I also don't like claims without facts to back them up.
 
I'm having a tough time with your logic here. I understand the theory you're running with. However, I would like to see an experiment with numbers to back that theory up.
Given the theory that cones move at different rates, they still have to react to the sine wave being delivered to the voice coil. If the cone reacts any fraction of a second behind the signal getting to its terminals, the cone will eventually either catch up with the signal or move in the complete wrong direction. I think it will catch up and move on-point with the signal. So that leaves a split second where they subs might be out of phase (unnoticably).
Also, given your theory is accurate, your two subs will always be a different distance from you, so you could argue that the different distances could actually make your subs sound louder by being ever-so-slightly out of phase. The sound waves/air vibrations have to travel from the speaker to any given point, so maybe the air vibrations would be more in sync by the time they get to the listener/meter.

Playing devil's advocate here, but I also don't like claims without facts to back them up.

Why not just go try it and see if you like it? Just use your knowledge and make your best educated guess. It might not be ideal, but it might work for now.
 
I'm having a tough time with your logic here. I understand the theory you're running with. However, I would like to see an experiment with numbers to back that theory up.
Given the theory that cones move at different rates, they still have to react to the sine wave being delivered to the voice coil. If the cone reacts any fraction of a second behind the signal getting to its terminals, the cone will eventually either catch up with the signal or move in the complete wrong direction. I think it will catch up and move on-point with the signal. So that leaves a split second where they subs might be out of phase (unnoticably).
Also, given your theory is accurate, your two subs will always be a different distance from you, so you could argue that the different distances could actually make your subs sound louder by being ever-so-slightly out of phase. The sound waves/air vibrations have to travel from the speaker to any given point, so maybe the air vibrations would be more in sync by the time they get to the listener/meter.

Playing devil's advocate here, but I also don't like claims without facts to back them up.

This isn't religion, there is no "theory."

We are talking pure FACT regarding cancellation. Overlay 2 different plots from a modeling program like Bass Box Pro and look at phase angle and group delay. The proof is in front of you- measured in degrees of angle and milliseconds.
 
This isn't religion, there is no "theory."

We are talking pure FACT regarding cancellation. Overlay 2 different plots from a modeling program like Bass Box Pro and look at phase angle and group delay. The proof is in front of you- measured in degrees of angle and milliseconds.
This is absolutely theory until FACTS are presented. A modeling program isn't the same as real FACTS (since we are capitalizing that word for some reason). FACTS come from experiments, not simulation. Again, if there are any (proven,) facts, I'm genuinely interested in the subject. "Proven facts" is redundant, but apparently appropriate for the audience.
 
Activity
No one is currently typing a reply...
Old Thread: Please note, there have been no replies in this thread for over 3 years!
Content in this thread may no longer be relevant.
Perhaps it would be better to start a new thread instead.

Similar threads

Also use the Orange wire. It will be constant 12v. Yes, you can bi-amp your co-axials. You just separate the tweeter wires ftom the terminals and...
1
107
Thanks for the input. Much appreciated. The dsp is an afterthought. I haven't installed anything yet but I put a budget system together. I already...
2
128
If you buy a replacement OEM Radio Harness the colors will match up then you can use a wiring harness to connect to that. According to a few...
1
305

About this thread

SkrillaPyles

CarAudio.com Newbie
Thread starter
SkrillaPyles
Joined
Location
Decatur, tx
Start date
Participants
Who Replied
Replies
38
Views
10,172
Last reply date
Last reply from
SkrillaPyles
DD451980-D607-41AB-B69C-6745AAE4B848.jpeg

SlugButter

    Mar 28, 2024
  • 0
  • 0
F98C6D78-7734-4659-9FCA-34969BDDC56A.jpeg

SlugButter

    Mar 28, 2024
  • 0
  • 0

Latest topics

Top