Can't tell if my subs are blown, need some help


d_tek

CarAudio.com Newbie
Dec 6, 2020
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0
Cincinnati
Hey guys, I'm wondering if you are able to tell whether the issue, as seen in the video, is with my subs or my amp. The subs play fine at a low volume, but once it reaches a certain threshold then it starts to have an issue. You can hear it at the beginning of the video and then again at around the 45 second mark. I appreciate all feedback, thank you.
 

audiobaun

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Id pull each sub and check them with an DMM for the acceptable ohm load for each sub since you have easy access to do so. While you are there.. Check for any leaks within the enclosure inside. Check to make sure that each sub has a secure connection as well as at the amplifier. Check RCAs make sure secure and not Kinked. Check all Power and Ground connections on that amplifier and the remote also so that you have a solid exposed wiring connection at the amplifier. Check the power supply connections and grounds for non-corrosive wiring. Clean any corrosion of any wiring connections.
These are a few things Id start with to find the Culprit.
There may be a possibility that you are reaching the limitations of the sub at a Htz level as well?
Another to be considered is the Recording of the music and method being used/source.
Just a couple things to be considered as well.
Let us know what you find. Others may be having similar issues as well ,and your findings to resolve the issue will help others.
SYSTEM, COMPONENTS AND VEHICLE INFORMATION NEEDED
What Type of Vehicle do you have ? Stock Battery,AGM? Stock Alternator? Size power wiring?
Model and make of HU?Amplifiers? Sub woofers?External fuses,Distro Blocks? Size of Ground wiring?Has the Big 3 been done?
 

hispls

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Generally if the subs were broken they would be giving you trouble at every power level.. There's something else going wrong here. Do please give us more details on amp, subs (impedance you're running), and electrical system. Are you confident that there are no wires shorting anywhere? How is your gain adjusted?
 

Buck

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That sounds to me like too low of ohms on the subs and the amp is going in and out of protect or something.
OP you need to get a DMM if you're in car audio. It's the most useful tool you can get, you can buy one for $20. You need to read what ohms your subs are wired to, in my opnion. I could be wrong, but you'll still need to start reading stuff until you figure it out.
 

Buck

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That sounds to me like too low of ohms on the subs and the amp is going in and out of protect or something.
Look and see if you have a red light that comes on on your amp where it's going into protect when this happens.
 

d_tek

CarAudio.com Newbie
Dec 6, 2020
14
0
Cincinnati
  • Thread Starter Thread Starter
  • #8
the amp is decently old so it doesn't have a protect mode indicator:(
the issue started when I was playing some music that had a bass line that is much higher than it should be (my buddy mixes his music without a sub, so I think he cranks the bass up because he can't tell how much there actually is)
the amp has played literally 10x louder than what is in the video with no problems and given that it still works at low volumes I really can't tell what the exact issue is. From my knowledge it obviously is the subs or amp, and the subs can still go as loud as they could before the issue started but it is only for maybe .5-1.5 seconds before the issue kicks in again
I'm on a stock alternator and my 4 channel amp sometimes will kick off when I can tell I'm at a lower voltage but my subs amp has never done this before so I'm not sure why it would begin to do so.
I'm gonna check out the impedance of the subs in a little bit so I'll let you guys know what I find
 

dragon.breath

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Nov 22, 2007
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I have seen a similar problem before. The problem in my case was a bad subwoofer. The voice coil had a bad spot in it. When it was cold it would make contact and play normally. When the coil started heating up it would start losing connection.
 

d_tek

CarAudio.com Newbie
Dec 6, 2020
14
0
Cincinnati
  • Thread Starter Thread Starter
  • #10
just tested it with a DMM, one sub read 4 ohms and the other read 3.6. What do you guys think?
 

jt4x4

CarAudio.com Well Known
Jul 22, 2019
302
92
ND
I'd start with listening to less shitty music and see if that helps.

If you push on the cones do you feel any friction or hear any crunching?

I think they sound blown, but tough to tell from a video.
 

d_tek

CarAudio.com Newbie
Dec 6, 2020
14
0
Cincinnati
  • Thread Starter Thread Starter
  • #12
I'd start with listening to less shitty music and see if that helps.

If you push on the cones do you feel any friction or hear any crunching?

I think they sound blown, but tough to tell from a video.
They sound fine when pushing down on them, or at least sound the same as before the problem started
 

jt4x4

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Jul 22, 2019
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And they are in the same enclosure as before the problem? That essentially rules out the box.

Did you adjust any settings on the amp recently?

Did ANYTHING change before your issue arose? Doesn't matter how insignificant it might seem. If you didn't change anything, then something broke.

Measure voltage at the speaker terminals of your amp to get an idea of how much power your subs are getting. That'll tell you if you are overpowering them.

You could try hooking them up one at a time to see if the noise is isolated to just one sub.

An oscilloscope would help, but I know most people don't have access to one or know how to use one. Any chance you are the minority who does?
 

d_tek

CarAudio.com Newbie
Dec 6, 2020
14
0
Cincinnati
  • Thread Starter Thread Starter
  • #14
And they are in the same enclosure as before the problem? That essentially rules out the box.

Did you adjust any settings on the amp recently?

Did ANYTHING change before your issue arose? Doesn't matter how insignificant it might seem. If you didn't change anything, then something broke.

Measure voltage at the speaker terminals of your amp to get an idea of how much power your subs are getting. That'll tell you if you are overpowering them.

You could try hooking them up one at a time to see if the noise is isolated to just one sub.

An oscilloscope would help, but I know most people don't have access to one or know how to use one. Any chance you are the minority who does?
really the only change between before the issue and after the issue is that I updated spotify. I use an EQ on there so maybe they changed the dB level of it after the update. Should've mentioned this though, I was listening to my buddy's music when the issue happened and he doesn't have a sub to mix with so on some of his tracks he cranks the bass line way up, which paired with two EQs is my guess of the root of the problem.
I know the subs are underpowered, if anything, because the amp's max output is 600 watts and it does 300RMS maybe (can't find a definitive answer for that, but the amp is a kenwood KAC-6104D; https://www.crutchfield.com/S-uT22BIYnFPV/p_113KAC6104/Kenwood-KAC-6104D.html). The subs themselves are crunch gtr12s4's and they have an RMS of 350 watts a piece
Unfortunately I don't have an oscilloscope, but I'll try out one sub at a time, from what I can hear (and see) it is both of them having an issue though
 

dragon.breath

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Definitely try the subs one at a time. They are wired together, so if one sub is shorting out....
 
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Lasherž

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Apr 27, 2020
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I've never heard that particular sound before coming from subs. My guess would be a loose connection on the signal cable or the amp going into protect like Buck said. It's possible that it's also a weak ground since it starts later on in a song. Do you get it while the car is at speed too? Lower voltage isn't quite as capable of bridging a bad connection gap as charging voltage. Instead of looking at your subwoofer I'm curious what your amp looks like while this is all going down. Any spark sounds near the connectors? Any lights flickering?

If it's the subwoofers then it's going to be the coils, but you'd smell them before getting to this point. Did they start stinking recently?

Spotify uses a lot of crappy compression in their audio but in general it should be fine. It doesn't sound like a clip to me and that's what would happen unless that box is wholly inadequate for those subs. They don't look like they're bottoming out either and the bass intensity didn't change between when it was having an issue and when it wasn't.. The only likely things that change throughout a bassy song with the same background rumble is that the coils heat up a little bit, the battery voltage goes down (and amperage goes up), and things that don't fit right are likely to vibrate loose.
 

jt4x4

CarAudio.com Well Known
Jul 22, 2019
302
92
ND
It sounds like burnt/scraping coil to me. It's tough to watch two speakers at once, especially in a video, but it doesn't look like the speakers are moving together.

Lasherz and Buck: do you think a protection circuit would cycle that fast? I would expect protection to shut it off for long enough to sound like it shut off and came back, whereas the video sounds like it would have to cycle faster than the audio frequency.
 

d_tek

CarAudio.com Newbie
Dec 6, 2020
14
0
Cincinnati
  • Thread Starter Thread Starter
  • #18
Alright just tested the subs individually, one of the subs didn't produce any sound on either channel so I tried bridging it and that did not work either. The sub that does work worked on both channels as well as bridged and didn't seem to have any problems with the issue at hand until I turned on the EQ. Prior to testing them individually, the sub that no longer makes any sound was still working, as you can see in the video. This makes me wonder if the issue is both the subs and the amp maybe? Let me know what you guys think
 

audiobaun

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Alright just tested the subs individually, one of the subs didn't produce any sound on either channel so I tried bridging it and that did not work either. The sub that does work worked on both channels as well as bridged and didn't seem to have any problems with the issue at hand until I turned on the EQ. Prior to testing them individually, the sub that no longer makes any sound was still working, as you can see in the video. This makes me wonder if the issue is both the subs and the amp maybe? Let me know what you guys think
I would still pull both subs and check the wiring connections( ON THE SUB, not the wires from the amplifier). The reason the Non -working sub is moving within the enclosure( acting as a radiator) is due to chamber pressure while the other is doing work.
 

audiobaun

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Sounds like Ohm loads are reading fine within limitations of 4 ohms each..Wired properly, you should be at a 2 ohm final load. You are going to have to learn how to clean up your music before you play it on your system as well. Bad Music Mixing and not knowing your limitations of your EQ settings can lead to Severe Distortion as well as Maxed tones /beyond your speakers and sub woofer limitations that will eventually damage them/ Hence... Start buying more gear/ digging deeper in your pockets... Just my 2 cents here
 

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