3 mtx subs on alpine amp, shuts off
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=108727
Printed Date: June 08, 2024 at 9:27 PM
Topic: 3 mtx subs on alpine amp, shuts off
Posted By: laughnowqqlater
Subject: 3 mtx subs on alpine amp, shuts off
Date Posted: November 07, 2008 at 2:33 AM
so i got 3x 10in mtx's hooked up to a 1000watt rms alpine amp and it works and sounds fine with like 3/4 of the gain up, but when i turn my cd player to 30+ volume (40 is max) for like 10 mins the subs stop working.. but when i turn my cd player off and back on, the subs work again? why does this happen?should i set the gains lower? or why is the amp shutting off when i try to bump for longer than 10 mins?
Replies:
Posted By: laughnowqqlater
Date Posted: November 07, 2008 at 2:35 AM
also, the subs are like 200 rms per sub.. so i have more than enough power to power them i believe.. correct me if im wrong
Posted By: i am an idiot
Date Posted: November 07, 2008 at 3:23 AM
How many voice coils are there on each speaker? What is the impedance of said Voice Coils? If 2 coils per speaker, How do you have the voice coils of each speaker wired? how do you have the 3 speakers wired to the amp? When this happens, can you leave your hand on the heat sink of the amp, or is it too hot? What is the minimum ohm load your amp can handle? If you do not know that, what is the model of the amp?
Posted By: DYohn
Date Posted: November 07, 2008 at 8:20 AM
laughnowqqlater wrote:
so i got 3x 10in mtx's hooked up to a 1000watt rms alpine amp and it works and sounds fine with like 3/4 of the gain up, but when i turn my cd player to 30+ volume (40 is max) for like 10 mins the subs stop working.. but when i turn my cd player off and back on, the subs work again? why does this happen?should i set the gains lower? or why is the amp shutting off when i try to bump for longer than 10 mins?
This happens because the amp is overloading, probably because the gain is set incorrectly and/or the speaker load is too great, or possibly because the system voltage is dropping too low. As was asked before, what is the total speaker impedance you are putting on the amp? And I suggest reading and following the "How do I set my gains" sticky thread. ------------- Support the12volt.com
Posted By: laughnowqqlater
Date Posted: November 08, 2008 at 1:39 AM
all 3 of the subs are 4 ohm svc.. so i cant really wire them in series.. i think it is putting out a 1.3 ohm load? and also if the amp is overloading.. if i set my gains lower would it stop doing this? like i said, it works fine for like 10-20 mins.. after that it starts shutting off... but once it starts shutting off... it will keep doing it if i try to turn it back up.. unless i let the amp cool off for a while.. than i can get the 10-20 mins again. i think its overheating maybe? if i keep the volume at like 22-25 it works just fine for a long time.. but once i start getting in the 30's for a while it will start shutting down
Posted By: laughnowqqlater
Date Posted: November 08, 2008 at 1:57 AM
the model amp is an MRP-M1000 i believe, 1000watt rms @ 2 ohm and 600watt rms @ 4 ohm, mono block class-d v power alpine amp.. i cant find if it is 1 ohm stable or not.. but it says something on the site about "Cooler Amps = No Shut Down" so i wonder why mine is heating up so much... and i forgot to say that i can put my hand on the amp.. but it does get pretty hot
Posted By: haemphyst
Date Posted: November 08, 2008 at 9:08 AM
It's NOT one ohm stable. Three 4-ohm voice ciols in parallel is 1.3 ohms, significantly below the rated maximum load (or minimum impedance) of 2 ohms.
You have 4 choices: 1) get rid of one woofer, and run only two. You will lose less than 1.5dB of total output, and it won't even be noticeable. 2) run all three in series, for a 12 ohm load, and power the three with somewhere around 100 to 120 watts each. Your total output loss will be right around 3dB from where you are now - also BARELY noticeable. 4) get another IDENTICAL woofer, wire them in series-parallel, and run a 2 ohm load, with 150WRMS to each woofer. 3) get a new amplifier - one that will run stably at the load you can provide - 1.3 ohms.
Those are your choices. There are no other options, so don't go trying to figure something else out.
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: i am an idiot
Date Posted: November 08, 2008 at 9:31 AM
haemphyst wrote:
4) get another IDENTICAL woofer, wire them in series-parallel, and run a 2 ohm load, with 150WRMS to each woofer.
He meant a 4 ohm load
Posted By: laughnowqqlater
Date Posted: November 08, 2008 at 12:21 PM
aight thanks for the info, do u think i hurt the amp at all? i bought it prolly a month to a month and a half ago..
Posted By: DYohn
Date Posted: November 08, 2008 at 12:37 PM
The amp shut down to protect itself so it is probably OK. Why do you say you can't connect 3 SVC speakers in series? Of course you can, and that is the best way to use them with your amp - assuming you must use all 3. ------------- Support the12volt.com
Posted By: haemphyst
Date Posted: November 08, 2008 at 5:43 PM
i am an idiot wrote:
haemphyst wrote:
4) get another IDENTICAL woofer, wire them in series-parallel, and run a 2 ohm load, with 150WRMS to each woofer.
He meant a 4 ohm load
Yep. My bad! ------------- It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: laughnowqqlater
Date Posted: November 08, 2008 at 5:55 PM
alright, i dont have to use all 3, im building a 2 sub enclosure (ported) so maye ill gain the dB back that im going to lose from not using the 3rd?
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