Cloud appears in front of speaker? What??

[sumaudioguy]

This only happens when the dew point and temperature are near each other, like 2-5 degrees F apart.

One day as I was cranking up to rock out my system just would not play as loud as I thought it should. I figured I have broken it but could find nothing wrong. So I cranked it up and started adjusting the volume up and down a little at the SPL it just would not go by. After about half an hour of this the light was right and I noticed that looking past the 6.5 inch (80-1000 Hz bandpass) the light was blurry. What the heck? So I positioned myself better and sure enough right when the system would not get any louder a little cloud appeared in front of the driver. Turning the system all the way up the cloud appeared to be about 3.75 inches in diameter and maybe 1.75 inched thick. I found adjusting the volume changed the opacity of the cloud but not the size much. That speaker with the 135 watt amplifier will peak normally at 107dBa at one meter but that day it would stop well below that with peaks maybe 101dBa. I did not measure the SPL but that is a good guess.

How can I fix this and has anyone else had this situation? What the heck????

My drivers cones are waterproofed in manufacturing and the cones are very stiff and heavy, 26 grams for the cone not including voice coil in the 6.5 inch. Yah that is a lot but that is what it takes to keep it from flopping like a flag in the breeze at high power.

Fix it- help me- surely someone has experience with this. I presume it had something to do with pressure change but I just want it fixed so I can rock out anytime!

[Moondog55]

GEEZ we wish you had a photo of this effect.

Anything like that shockwave condensation in front of the FA _ 18 that was featured a while ago??

[planet10]

Originally Posted by sumaudioguy

will peak normally at 107dBa at one meter but that day it would stop well below that with peaks maybe 101dBa.

Even with very dynamic recordings with 20 dB peaks (not much R&R) you are playing loud enuff to cause permanent hearing damage... keep it up and you won't have to worry, you'll be deaf.

The cloud is sending you a message -- you are creating enuff SPL to change the local weather.

dave

[prickears]

I agree with Dave on this 1 for sure, I have only seen this kink of stuff happening on F1 and indie cars and jets. It is caused by low pressure, so it does strike me as a little strange that it should appear in front of a driver.


Call myth busters and learn sign language fast, would be my advice!

[Inductor]

The Eldridge (or Mr. Tesla) is coming back. Keep the gate open, sumaudioguy... (Don't tell the CO2 guys or you will have to pay for global cooling)

[MisterTwister]

can you take a photo of this effect? I guess high spl causes this hallucination.

[studiotech]

Could it be smoke from something else, if you catch my drift?

[sumaudioguy]

Did try to photo it but needed the tripod set up. This has happened 3 times so I thought next time would try the tripod.

Interesting, so the double convex lens looking cloud is low pressure caused by when the midrange moves into the cabinet during music. Very curious. Hummmm

As far as the SPL, even a rep came through and I told him this is 107dB peaks and he said "no way" and I said yes really. So he went and got his SPL meter out of the car and measured himself and said, "I heard 107dB today at another location and this is not nearly that loud but the meter says it is." I said "Ah yes, you heard distortion loud and this is music not distortion." That feeling that the sound will rip the ears from your head- that is a lot of non-harmonic distortion (piling up in the high frequencies) which sounds and is very loud causes hearing damage. This does not particularly as average is much lower anyway and the lack of high frequency garbage makes the experience quite compelling rather than painful. No measurable hearing loss from loud audio yet... but there is always hope.

[David_Web]

Well when you get loss of hearing you know it's way past too late.

Still, loud once in a while is nice. Got to love dynamics.

[johnr66]

Lowered pressure in a gas causes lower temperature. If the dew point is close to the temperature, the lowered temp in the low pressure region means the air becomes over saturated and the water vapor condenses. That is the fog you see. Since a speaker can affect air pressures enough at close ranges, it is certainly possible to see a "cloud".

I suppose at the right frequency, there is a standing wave that holds the cloud into position. Would be neat to see the shot.