I blew my sub? - Audio & Electronics Forum

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I blew my sub?
Thursday, April 20, 2006 5:40 PM
Ok so I have one of last years model TS-W1500SPL's lying around so I decided to put it in my trunk while one my amps is out on repair...well i was reading lanmans sticky, and it showed me how to properly set amps...I calculated that I needed 34.64 volts to be properly set, so i set it so the amp maxed out at 34~ volts...Then I hooked up my sub to see what it was playing like compared to before. Well the freq sweep lanman posted seemed like a good test, so i let it play and about 20 seconds in...the sub made a pop and i was like....f**k now, I dont know if maybe i did something wrong, or if the sub was on its last limb or something (i had the gain too high for a while, because i had to turn it down to make it right) but ... I dont think thats right...like my sub blew after i properly set the gain...I had all Eq's off still i didnt change a thing, so this is kinda weird imo... Like i know the voice coil is f-ed because it makes a scratchy noise when i push the cone, and it was makin a less scratchy noise before it blew, but it still played normally....so does this seem like i was clipping it before, then just put it over the edge trying to play low frequencies through it? or do you guys think i set my amp wrong and need some serious help I dont really care about that sub, i have two of the 3004spls sittin in my basement, but i dont wanna blow those cuz they're my main subs ... but yeah what do you guys think...and if someone could answer my question in lanmans post too, that would be great as well

wysiwyg wrote:i would say they bang, they don't really pound so much. but if
you want to bump, then they will bump and hit real hard and a lot good.

LOL

Re: I blew my sub?
Thursday, April 20, 2006 9:31 PM
What are the specs of the sub and amp?

You can match the RMS of the amp to match the RMS of the sub, but if the peak of the amp is higher than the max power rating of the sub, it can still blow it. Though I doubt a sweep test would peak a sub, it's a possibility.

Just to review:
sqrt (RMS power * Impedance of speaker)

Are you sure you had it wired to the right impedance?

2ohm Dual Voice Coil, wired series

AMPPOS -> POS (coil1) NEG -> POS (coil2) NEG -> AMPNEG

4ohm


2ohm Dual Voice Coil, wired parallel

AMPPOS -> POS(coil1) -> POS(coil2) -> NEG(coil2) -> NEG(coil1) -> AMPNEG

1ohm

I'd draw a pretty picture, but this computer is hella slow



Re: I blew my sub?
Thursday, April 20, 2006 9:37 PM
Bah, descriptions of wiring were bad and wrong

Here's some pics i stole from www.bcae1.com

2ohm Per Coil
Series

4 ohm Total

2ohm Per Coil
Parallel

1 ohm Total



Re: I blew my sub?
Saturday, April 22, 2006 9:41 AM
Ya i know all that stuff, im not that noob the sub is 600rms and 1500max and the amp is 600rms and 1000max@2 ohms, i have the sub wired to 2 ohms (dvc 4 ohm coils wired in parrallel...) ... but my main question is do you think that the sub could blow, if the amp was clippin before (like does clipping just blow the coils instantly or does it destroy them over a period of time) does the clipping weaken the coils, then once i set up the amp right, would playing low frequencies below the tuning of my box, pushin the sub really hard, push it over the edge and cause it to blow?

wysiwyg wrote:i would say they bang, they don't really pound so much. but if
you want to bump, then they will bump and hit real hard and a lot good.

LOL
Re: I blew my sub?
Saturday, April 22, 2006 10:27 AM
Chris H wrote: my main question is do you think that the sub could blow, if the amp was clippin before (like does clipping just blow the coils instantly or does it destroy them over a period of time) does the clipping weaken the coils, then once i set up the amp right, would playing low frequencies below the tuning of my box, pushin the sub really hard, push it over the edge and cause it to blow?


Clipping creates heat that can scorch your coils, but it usually takes more than a second or two to completely fry them (unless you really clip them) because it takes some time for the heat to build up and damage them. I see no reason why clipping wouldn't weaken a VC - it's completely possible that the sub was just on it's last legs.

Playing frequencies below the tuning frequency of your box (at high volume) can also kill a sub because, below the tuning frequency of your box, the box itself provides little or no damping for the sub. At that point it's just the sub's suspension controlling the cone's movement.

Hmm, my brain isn't working (no sleep), but this article might say it better:
http://72.14.203.104/search?q=cache:Ne1uWQD48SgJ:www.bcae1.com/spboxad1.htm+playing+below+tuning+frequency+ported&hl=en&gl=ca&ct=clnk&cd=1&client=firefox-a

With ported boxes, it's a great idea to use a subsonic filter. The general rule of thumb is to set it to cut frequencies 10Hz below your box's tuning frequency (so if your box is tuned for 35Hz, set the SS filter to 25Hz). That's just a rule of thumb, and it depends on your application. SPLers like myself usually set our subsonic filters at or just below the tuning frequency (to both reduce power waste and save our subs). Some people go 5Hz below, and some guys just set it to 20Hz and never have any problems.

Anyhoo, hearing those noises isn't a good thing. Get 'er reconed!



The 50-50-90 rule: Anytime you have a 50-50 chance of getting something right, there's a 90% probability you'll get it wrong.
Re: I blew my sub?
Saturday, April 22, 2006 10:39 AM
Thanks! That answered my question

wysiwyg wrote:i would say they bang, they don't really pound so much. but if
you want to bump, then they will bump and hit real hard and a lot good.

LOL
Re: I blew my sub?
Saturday, April 22, 2006 4:38 PM
You're quite welcome!
If you have any other questions, just post em up. With all the audiophiles here (especially the likes of Lanman, Wsyiwyg and Sndsgood, among others), someone should be able to answer them.




The 50-50-90 rule: Anytime you have a 50-50 chance of getting something right, there's a 90% probability you'll get it wrong.
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