subwoofer help Dual Trunk Car Subwoofers issue

[Joid15]

So in my car, I have installed dual subs in my trunk. Both subs are the same. 12inch Kenwood KFC-W3005. They are both in the same sealed box. From what I can see from specs, I have enough wattage to support both subs. However, when I play music with both being powered, it stops hitting low frequencies. They will still play really loud, but miss those low notes. Then, if I unplug either one, and allow for only one of the two to play by itself, it sounds perfect. Hits all of the frequencies. Both will play perfectly, only as long as it plays without the other sub. Is this still a power issue even with a good Amp? Could it be airflow? Maybe with two playing in the same air tight box they suffocate each other? (FYI, they are facing towards the driver's seat). I do also live in a higher altitude and have driven the car from a different state with a very different altitude. 

[OhioYJ]

How do you have these speakers wired? You aren't trying to run these in bridged mode or past an impedance rating it's rated for are you? Most amplifiers will go into a protect mode or shut down if the impedance drops below what they are rated for to protect themselves. (IE if you have it wired wrong, or the wrong type of speakers wired to it)

[sk8rs_dad]

Check the polarity. If they are wired out of phase then the lower frequencies will be attenuated due to the cones moving in opposite directions. 

[Joid15]

2 hours ago, OhioYJ said:

How do you have these speakers wired? You aren't trying to run these in bridged mode or past an impedance rating it's rated for are you? Most amplifiers will go into a protect mode or shut down if the impedance drops below what they are rated for to protect themselves. (IE if you have it wired wrong, or the wrong type of speakers wired to it)

Should be wired correctly. I've got a power cable connected to the battery. I've also got power and radio control over it by using a line output converter. Then from the amp I've the the speaker wires connected to the speakers. Maybe I'm going past the impedance rating? I'm not entirely sure, and after looking it up it almost seems as tho my amp doesn't even exist.

[Joid15]

2 hours ago, sk8rs_dad said:

Check the polarity. If they are wired out of phase then the lower frequencies will be attenuated due to the cones moving in opposite directions. 

I could try to move them around and see what happens. 

[emosun]

Everything you're using appears to be several decades old and in pretty poor condition , were you expecting them to function correctly or?

[Joid15]

2 hours ago, emosun said:

Everything you're using appears to be several decades old and in pretty poor condition , were you expecting them to function correctly or?

Fair enough. I mean hey, at least when I have only one powered I still get good and loud bass. I was just hoping to try and get both to like each other and not have problems when playing at the same time.

[Heats with Nvidia]

10 hours ago, Joid15 said:

I could try to move them around and see what happens. 

This is what happens, when both are out of phase with each other. This means their polarity is different. Just switch the polarity of one of the speakers and see, if this is better. If its better, it makes sense to also switch the polarity of both together and see if it sounds better with the rest of the system or not. Also the surrounds of both speakers are damaged. This will cause weird air noises coming from them when the cones move a lot.

[Joid15]

7 hours ago, Heats with Nvidia said:

This is what happens, when both are out of phase with each other. This means their polarity is different. Just switch the polarity of one of the speakers and see, if this is better. If its better, it makes sense to also switch the polarity of both together and see if it sounds better with the rest of the system or not. Also the surrounds of both speakers are damaged. This will cause weird air noises coming from them when the cones move a lot.

I was worried about the damage, but I call them miracle woofers because they sound really good, and I honestly don't hear any weird distorted sounds from the damage. I mean, I'm sure there would be a big quality difference if they weren't damage, but even when they are it's not super noticeable.

[Joid15]

7 hours ago, Heats with Nvidia said:

This is what happens, when both are out of phase with each other. This means their polarity is different. Just switch the polarity of one of the speakers and see, if this is better. If its better, it makes sense to also switch the polarity of both together and see if it sounds better with the rest of the system or not. Also the surrounds of both speakers are damaged. This will cause weird air noises coming from them when the cones move a lot.

Moved them around and I think that fixed it. I only tested with 2 songs, but from those 2 songs I can definitely tell that they got significantly louder and are able to hit deeper notes than before. Both are bumping and it sounded great. To be safe, I'm gonna listen to them a little longer and might do as you said and switch both to see if it somehow gets better before I mark this as fixed. Thankyou, and thankyou to Sk8rs_dad.