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Discussion Starter · #1 ·
About a month ago one of my two SDX15s blew. We had the system charged pretty well during a party when I smelled the "too hot" driver smell - like Bandaids, then turned it down. A couple of days later I noticed that one of the drivers was blown, yet it was the other one that had that smell. I have been gentle with it since, even bumping up the HPF to over 20 and cutting the level on the EP4000 to half (it is bridged). Yesterday the 2nd one blew. A song with a bass drop came on and CLANK on the first note - bye bye.

So, 2 recone/recoils is almost $300. I believe that the problem is obviously the user, not the product. I need to turn it down or get something that gets deeper and louder without exploding. I don't really want to turn it down, can I get an amen? I like to turn it up to 11.

Any new ideas before I send these in?
 

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Elite Shackster
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Sounds like you might be running them sealed, is this the case. If it is, the obvious solution is new cabs, larger and ported.
 

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Elite Shackster
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If your running ported then you really shouldnt be over powering them. Its always worth bearing in mind that if you half the power you only loose 3db. I would bridge the EP4000 and see what happens to try be on the safe side.

I would make sure you HPF is set so you dont get over excursion as well. Use you WinISD model for where best to set it. With a 16hz tune, you wont want to be much below 15hz for the HPF.
 

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Discussion Starter · #5 ·
It was bridged at the time of the explosion - both were on their own amp bridged originally. I think the one that just blew was damaged when the first one blew out. I just completed ruining it later. I thought that if it was a 19hz tune, that the HPF should be set at 5 below at 14. During testing with test tones, the lowest frequency that I really notice is 16hz. Anything lower just makes rattles in the house and in my flesh. It makes sense to me to set it at it's tune, like you say Moonfly. It is difficult to tell on the Reckhorn B-2 since the dial is not exactly precise.
 

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Personally I think it's easier to fry a sub in a larged ported enclosure than a sealed. Sounds like too much power and an improperly set HPF. You have already mentioned and I recall hearing that the B2 is not too accurate as far as a HPF so who knows what it was set at.

Your probably better off just running both subs off of a single EP4000, this way you will more than likely be amp limited instead of frying another set of subs.
 

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Elite Shackster
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Typically a driver in a ported cab will get close to max excursion with less power than it will in a sealed, and they usually dont use anything like the power the motor can handle. Sealed on the other hand are much more power hungry and will suck up that power while the cabinet suspension helps prevent the driver from too much excursion. This isnt always the case, but its pretty typical.

Cooking drivers motors is a bigger issue in sealed sub than ported IMO, as is amp clipping.
With ported designs, the bigger issue is drivers bottoming out.
 

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Neither one of us is looking at a model of the design but at first glance a pair of bridged EP4000's into a pair of 6.6 cuft ported enclosure SDX15's sounds like the likely culprit.

I should have worded my response better, when I say a fried driver I was mainly talking about any kind of failure. Both sealed and ported have the positives and negatives but ported takes much more care with regards to power and a properly placed HPF IMO.
 

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Discussion Starter · #9 ·
I should build a sealed enclosure for some testing and compare the two enclosures when I get them repaired. I am far too attached to them to not have them repaired and put them back in service asap.

Side note: I have some 20 year old Cerwin Vega 3-way loudspeakers with 15" drivers in them that serve as the garage speakers... I stole the drivers from them and put them in the place of the SDX15s and they actually sound pretty nice. A far cry from the SDX15 though, but will do in the meantime. I can even watch a movie anymore without proper sound.
 

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Elite Shackster
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Neither one of us is looking at a model of the design but at first glance a pair of bridged EP4000's into a pair of 6.6 cuft ported enclosure SDX15's sounds like the likely culprit.

I should have worded my response better, when I say a fried driver I was mainly talking about any kind of failure. Both sealed and ported have the positives and negatives but ported takes much more care with regards to power and a properly placed HPF IMO.
Ahh, by fried I took it to mean fried the voice coil.

For a model, the OP supplied a link for me in an earlier post to his original build thread for these.

Ported will be at greater risk from damage from too much power, although a HPF should help prevent that happening, but that damage will more likely come from driver bottoming. The op describes a burning smell, which could be the culprit if more power is put in and the HPF is preventing bottoming.

I should build a sealed enclosure for some testing and compare the two enclosures when I get them repaired. I am far too attached to them to not have them repaired and put them back in service asap.

Side note: I have some 20 year old Cerwin Vega 3-way loudspeakers with 15" drivers in them that serve as the garage speakers... I stole the drivers from them and put them in the place of the SDX15s and they actually sound pretty nice. A far cry from the SDX15 though, but will do in the meantime. I can even watch a movie anymore without proper sound.
Sealed are ok, I actually prefer sealed subs, but if your used to the kind of output of these in ported cabs, the sealed will seem a fair bit weaker at the bottom end, and you might well miss that quite a lot.

I doubt you would stick with sealed and my own feeling is it isnt really worth the experiment unless its just for curiosity.
 

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I did model your set-up and it doesn't look bad except you run out of excursion at about 16hz with a 15hz HPF when running 2000 watts. Your under excursion with a 20hz hpf and you don't really lose alot and you can still send them a bridged EP4000 each.

The SDX15 does look better in the ported enclosure you made then a sealed.

I didn't want to make a ported vs sealed discussion here, just trying to add something.

How long were you playing your system when you smelled the burn?
 

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Wow Dougc,

I just looked at your build thread, outstanding work.

Really strange that both subs would fail, we need a sub detective to chime in.....hmmmmmm
 

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Elite Shackster
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IIRC, one failed after a very loud session. The other might have got fried because the power from the amp(s) wasnt reduced and was all being put into one driver, which no doubt got its level increased as well to compensate for the first ones failure.

I speculate though. It is important to be mindful of power distribution in your system however, especially when you have a lot more power than your subs can potentially take.
 

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Discussion Starter · #14 ·
Sub_crazy:
It was moderate levels for a couple of hours, then pretty loud for a couple of hours with booty shakin tracks - rattle the sliding glass doors and the neighbors hear it 2 doors down from inside and come over to enjoy (we throw notoriously good parties). That is when I noticed the smell of drivers cooking. Since then the smell returned whenever the sub was on. No smell now though!

Mike:
Thanks!! All fingers point toward me in the final investigation ;)

Moonfly:
there is an amp for each sub, so no power from the amp was increased or changed. I don't turn on amp #1 without sub #1. I did raise the HPF a little after the first one failed (not enough). I suspect that the main volume was increased more than normal since I was most likely used to hearing the LF that 2 subs make.
 

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Folks on this forum seem to know a lot about pushing subs to the limits (or beyond from time to time)! I've blown a few in my time, but is usually because of something going wrong mechanically due to over-excursion in small enclosures.

On the ported versus sealed, sealed can usually take (or need) more power and have a greater chance of overheating a voice coil. I was wondering, just how much heat is passed from a driver to the air in the box? If driver is less than 1% efficient, that means with even just a 10 watt average input, the air in the enclosure would be receiving 9 watts. A nine-watt light bulb in a well insulated enclosure would get the air very hot very quickly. Higher-end drivers made in the last 15 years vent to the magnet side (i.e., no more breathable dust covers, or no dust cover at all anymore), which worsens the issue.

Getting to the point - do ported generally also not toast voice coils just because of the air that is able to pass through the port to the room? Or, does that air pretty much just vibrate back and forth in the port and not allow any cool air into the enclosure?

About 20 years ago, I built a box in the trunk of my car. It was ported with the ports firing up through the rear shelf. I actually installed the amps in the inside the box on the bottom, with heatsinks facing up. The amps actually stayed cool. These were also really old school inefficient Class AB amps. I don't know if it was because of simple natural convection with the heat going out the port, or "forced" convection by the air movement through the ports. The ports were relatively short (I think about 5" long and I think about 40 hz tuning). Air may have been able to pass completely through the port on each vibration of the port.
 

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Elite Shackster
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Sub_crazy:
It was moderate levels for a couple of hours, then pretty loud for a couple of hours with booty shakin tracks - rattle the sliding glass doors and the neighbors hear it 2 doors down from inside and come over to enjoy (we throw notoriously good parties). That is when I noticed the smell of drivers cooking. Since then the smell returned whenever the sub was on. No smell now though!

Mike:
Thanks!! All fingers point toward me in the final investigation ;)

Moonfly:
there is an amp for each sub, so no power from the amp was increased or changed. I don't turn on amp #1 without sub #1. I did raise the HPF a little after the first one failed (not enough). I suspect that the main volume was increased more than normal since I was most likely used to hearing the LF that 2 subs make.
This makes the most sense to me, and I think most of us have been guilty of this on more than one occasion. One good thing, you certainly know the limits now. One bad thing, you now know more subs wouldnt be a waste :devil:
 

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Discussion Starter · #17 ·
Speaking of over excursion - sealed enclosures help reduce over excursion since the cone has trapped air to cushion it's travel, but the coils get hot with no new air in there. Is there anything other than a HPF that slows the air from the ports to keep the cone from travelling so much? Smaller diameter or longer port tubes? I made what was recommended by the modeling and didn't think much past the science there.

I made the video with the towel over the port to show that it sucks air in as much as it pushes it out due to the pressure shift, of course, bringing new air to the coils. It's more of a mass of air than a burst from the ports in my enclosures. I hooked up a slot ported enclosure I made for my boat to my EP4000 for testing when I built it. It's tuned to 30 something with a JL13w7 and it blew the carpet over sideways with the port speed and you could feel the air from 3 feet away at least. Doesn't matter if there could be port noise because you wouldn't be able to hear it. The bass is deafening. The driver doesn't have near the amount of excursion as the subs for my home, but then again it's tuned higher, but still using a HPF of 20. It gets the low notes just fine even with the higher tuning.
 

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i have the sdx15 as well in a sealed box and usually after about 15-20 minutes of playing some tunes i will get a burning smell coming from the sub, it will be hot to the touch too so i would have to turn it down a bit or stop spin tunes to let it cool down.
i was kind of thinking of the same thing and making a ported box for this sub to solve this situation, this will force me to be more carefull of my volume and power outputs to the sub. Or just get another 3 more sdx15 :ponder:
 
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