Froze up (smoked) Velodyne DD-15

[supermotrad]

I have a question. I seem to have destroyed my "new" Velodyne DD-15 using test frequecies I down loaded from the net. It was in the 20-30 hz range starting in 1hz intravels,. when I got to around 28 I think, it made a funny sound, then the after turing it off the driver coil was scratching against the magnet, when pushing it in. I opened it up and the driver was smoking. I did run frequencies as low as 10-20 through it also, just vibrated the walls a bit like a D-9 CAT was parked outside idling, really. Still set at 25 or higher Db.
The amp is just a Yam 2700, the setting for everything 2700 and sub is low, and the Yams dial was at about 25-30 db when it caught fire. Duration total was probably 3 minutes total, at different frequencies 20-30. It wasn't flopping up off the floor so I thought it must not be driving it too hard?? What did I do to it that was wrong? I read the instructions for the test tones and they said as long as you keep the volume down to a normal level it wouldn't damage anything, same for the whole spectrum 10hz to 20k checking the rest of the system. Will this kind of test smoke all drivers or just big powered subs? Shouldn't the house have fallen down first, to give me a clue that the sub was being overworked? Maybe just a bad driver? Thanks

 

[j_garcia]

OK, so you had the Yammie at "normal" listening level, but what was the actual sub output level and what volume did you have the DD-15 set to? I've tested a few subs with 16Hz tones at calibration levels without issue. I've also played with the DD-15 previously and found it to be quite capable of handling fairly deep notes, however a 10Hz tone played too loud could very well push most subs to their limit. That is why I have a subsonic filter on my sub at 14Hz... If you did the damage in the 20-30Hz range there was either something wrong with the unit or you did have something turned up too high.

 

[Seth=L]

If there is a rubbing sound it means the coils heated and expanded. It was being pushed to hard or there was a defective part, woofer or amplifier.

 

[supermotrad]

ok, I started listening at around 10 or so, did 10 then to 15 15 could be felt not heard, around 18 you could hear it, then at 20 it was really heard 23 even more, I think it was at 23 when it melted. But maybe it was set at below 20 for too long?? 2 minutes?? can't remember perfectly. Maybe that got it cooking, then the rest of the test, above say 18 was just too much to do after being below 20 for too long? I bet that did it. Below 20hz. The volume for the sub was set at about 40%. So is it ok to test at Frequecies above 20 then?? I don't want to blow my other one up! Will testing constant tones in general overheat drivers? I'm always playing too much!! THANKS

 

[markw]

Test tones can be dangerous.

Sub-sonic bass in music and movies is rare and not continuous in nature.

With test tones, you can feed a tortuous signal to a sub and, even though you may not hear it feel it, it's still going through the amp and to that voice coil.

And, voice coils, being fairly delicate, can overheat quite easily when fed continuous high levels* of sub-sonics.

* Note I didn't say "loud". just because you can't hear it doesn't mean it's not doing the best it can to reproduce it.

 

[j_garcia]

Um, 2 minutes of anything below what you can acutally hear is a very good way to kill any sub.

The problem with infrasonic frequencies is if there is no protection for the driver and you feed it with something that is lower than it is physically capable of, distortion is almost certain to be the result and as a result of that you get lots of heat as the system tries hard to do what you are asking. As it tries to do this, the power draw is also through the roof because it is trying to do something it simply can't...

 

[Ron Temple]

I hope it's under warranty...

 

[j_garcia]

Maybe if he is real nice and doesn't mention the test tones, they will honor the warranty too.

 

[markw]

Maybe if he is real nice and doesn't mention the test tones, they will honor the warranty too.

Maybe. Remember, they specify design limits and uses for these things. And, they designed the amp that drives this speaker, too. they might take one look at that smokin' VC and label it abuse. But, it's worth a try.

 

[Sheep]

Maybe if he is real nice and doesn't mention the test tones, they will honor the warranty too.

If that happens, I will personally email this thread to Velodyne and have his warranty voided.

If you want to run test tones, use the internal calibration ones. What you did is for cheap car audio boom subs, not a DD-15.

Seriously, people have what they don't deserve.

SheepStar

 

[j_garcia]

I'm sure most companies expect people to test the limits, hell I threw everything I could at my PB-10 when I got it... but yes, this one certainly qualifies as "not covered".

 

[Adam]

Lessons here? First, don't drive a sub like that for two minutes. Second, if you do, don't post it on the internet before you contact the company about the warranty.

 

[dave1490]

If there is a rubbing sound it means the coils heated and expanded. It was being pushed to hard or there was a defective part, woofer or amplifier.

lol sounds like you need a new coil,if you take it apart you,ll see the coils just hanging at 45 degree off center lol a classic.

 

[dave1490]

ok, I started listening at around 10 or so, did 10 then to 15 15 could be felt not heard, around 18 you could hear it, then at 20 it was really heard 23 even more, I think it was at 23 when it melted. But maybe it was set at below 20 for too long?? 2 minutes?? can't remember perfectly. Maybe that got it cooking, then the rest of the test, above say 18 was just too much to do after being below 20 for too long? I bet that did it. Below 20hz. The volume for the sub was set at about 40%. So is it ok to test at Frequecies above 20 then?? I don't want to blow my other one up! Will testing constant tones in general overheat drivers? I'm always playing too much!! THANKS

not to brag but jbl does that at the factory before it sold.

 

[mike c]

when using test tones:

always start from the higher frequencies ...
measure with an SPL meter to make sure you don't exceed 75-85db (at the higher freqs.)
make sure the grill is off ...
don't play the tones too long ...
when playing the low freqs., you're not gonna hear it, but you're gonna see the driver flapping about trying to fly.

conclusion:
I say you played the 10hz tone TOO LONG and TOO LOUD (high SPL)

 

[Warpdrv]

Can you maybe identify the "Test Tones" you downloaded from the Web....

SIN waves could maybe be a bit extreme and damaging for a subwoofer...

Let us know what you used... Id be interested to hear what it was...

Warp

 

[mike c]

conclusion:
I say you played the 10hz tone TOO LONG and TOO LOUD (high SPL)

wait a minute ... the DD has a default 15hz subsonic filter set to 24db/octave

did you change the octave?

 

[MACCA350]

From the DD Manual:

Protection Circuitry
Your new subwoofer is equipped with special protection circuitry to provide maximum performance with greatest reliability.

The unit is protected against:
1. Overdriving the speaker or amplifier.
2. Overheating the amplifier.
3. Excessive drop in power line voltage.

The first type of protection circuitry that prevents overdriving of the speaker or amplifier operates constantly without being audible under most situations. In some extreme situations (sustained high output levels such as pro sound usage), the unit may shut down momentarily. This indicates operation of the thermal or under voltage protection circuitry. If this should happen, you should reduce the volume setting or shut the unit off until normal operating conditions return. You may also want to plug the unit into a different wall outlet, as dropping power line voltage will be most noticeable under strenuous conditions.

I wonder if your unit was faulty.

cheers

 

[supermotrad]

Thanks to everyone who lended their knowledge and not bitterness towards learning. I'm sure it's my fault now. It tried soo soo hard to "swing" it. Anybody see the goofy 5 foot aluminum woofer the Myth Busters made connecting the driver to the drive shaft of a car to mechanically move the cone up and down with a crank shaft assembly.

 

[Seth=L]

From the DD Manual:I wonder if your unit was faulty.

cheers

Let us hope that this was the problem. It is disheartening to have a piece of equipment crap on you doing something you thought was reasonable.