Checking subs and amp with DMM

[Bobby322 10+ year member]

Long story short...subs quit working when I had it cranked loud for like 5 seconds. Not sure if the amp went into protect or what...but the subs havent been working. The amp turns on and the power light is lit (not protect light). Everything works except my 2 subs.

I took the subs out, looked at them and they appear to be good. I checked the wires and they were all good and I re-did them just in case.

I got out my continuity tester, and I tested all the wires (RCA, sub wires, sub to sub voice coils) and they all are connected. I checked the fuses and they both showed that they were good on the tester.

The voice coils on the subs look the same as when I got them so I dont think I fried it. When I push down on each sub I dont hear a "scratchy" noise, so no idea what would be the problem on the subs.

I just un-hooked everything and put it back together and still get the same result. So im thinking maybe the amp isn't putting out any power, but it still turns on.

I tried getting out my DMM but its broken, so im going to get a new one tomorrow.

When I test out the subs to check if they aren't screwed up, the DMM should read 2 ohms, right? They are 2x2 ohms.

Also, is there a way to test wether or not my amp is putting out power with the dmm?

subs - http://dls.se/en/car/prod.html?produkt=en_138

amp - Hifoncis 1606D

Any help is appreciated, really dont want to send my truck to the audio shop.

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[Bobby322 10+ year member]

up

 

[psych0ticnemes1 5,000+ posts]

I have had this happen before. For some reason the amp would just not output power. The easiest way to tell would be to hook your dmm to the speaker terminals on the amp and turn the gain. If your voltage goes up, the amp must be producing power.

Sometimes it is something really dumb, like you have the subwoofer output on your head unit off. Check your head unit settings.

 

[Bobby322 10+ year member]

okay ill just hook to dmm into the terminals on the amp. What should the DMM be set to?

I have the setting right on HU. It just cut out when it was playing a few weeks ago. didnt hear or smell anything abnormal

 

[smgreen20 10+ year member]

Your subs are "scratchy" when you push down on them?

That's the number 2 sign of blown subs. Number one sigh would be fire/smoke. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif When speakers short or the coils burn, they usually burn in half. That break in the VC is where the scratching sound will come from as you push on the speaker cone. It also opens the circuit so that the amp no longer "sees" a load to "push", which is why you have no sound.

For a simple test use one of your mids (preferably an extra speaker you might have laying around) and at LOW volume, hook it up to the sub amp and see if the speaker plays. If it does you can now rule out the amp.

Set your DMM to VAC

 

[Bobby322 10+ year member]

no they ARENT scratchy.

just bought a dmm. need to know which settings to use

 

[Bobby322 10+ year member]

no they ARENT scratchy.

just bought a dmm. need to know which settings to use

 

[nineball 10+ year member]

set it to ohms and read each voice coil of each sub. it should be somewhere around 2, like 1.4-2.0 or so.

 

[Bobby322 10+ year member]

well i went through all the settings on the dmm and i was getting alot of 2's haha. some had decibles in front and stuff overall i was getting 2's so i guess im good. still havent hooked it up to amp. would i be able to somehow hook a 6x9 up to the amp to test it?

 

[Bobby322 10+ year member]

??