Soft and distorted siren: water in speakers?

[TexasFireMedic]

Siren: V-con


Speakers: 2 CP100Bs


All worked fine until went through car wash (laser wash, not typical one we go to) yesterday. Output is very weak and sounds distorted. Have not ran unit long, worried about possible wet driver, but these use synthetic and not paper material, right?


Both speakers sound the same. No water noticed in lower ports, but is it possible that water has frozen inside? Will they come back once they dry? Any thoughts?

 

[theroofable]

Im not sure about that one, but I had another style of speaker ruined by water, it was going about 3/4ths as loud as it used to.

 

[Respondcode3]

You have water in them.. That is why its important to pay attention to the way the speaker is mounted. Speakers have a small drain hole on the bottom to let the water out. Water freezing in the speaker can damage the diaphram of the driver.If you can get some compresed air and blow them out then make sure they are mounted properly. If they are then the drain hole may be blocked. Take a toothpic and try to clean the hole. Using anything else may damage the speaker.

 

[TexasFireMedic]

So, went out this afternoon and worked. Opened up driver side speaker (little more than a year old). Was quite clean, very light corrosion on metal in certain places, nothing out of the ordinary. 11.4 ohms. Passenger side (brand new, doesn't even have a response on it yet). 9.5 ohms.


Wiring tight. Suspected (as had been suggested locally) that the old ex-police v-con had dropped a transistor. Pulled the SA365 from the other car out, pulled horn ring and new speaker leads off V-con. Mounted Carson behind dash.


I greatly prefer Carson's tones over the Code-3, so am planning to achieve changing tones for intersections by horn ring on the Carson. Will leave Code-3 on wail most of the time and continue using it for light control. Horn transfer relay activated from aux switch so I also get a status led in case I leave it on.


They sound good.

 

[JPBC4]

Mine is kind of doing same thing except its not soft. It is intermittent like it has a lose ground or something. I thought it may have been the speaker and replaced it and still doing same thing. I have whelen speaker and motorola spectra astro siren. I'm stumped on this. I checked all grounds and connections and they seem fine. any thoughts? I hope its not the actual motorola siren control going bad.

 

[TexasFireMedic]

It's cutting completely on and off? Sounds like a bad connection. Have you checked power feed?

 

[JPBC4]

It's cutting completely on and off? Sounds like a bad connection. Have you checked power feed?

siren always activates and never cuts off completely. Hard to describe almost like a continuous popping sound. Its not smooth sounding and its very noticeable whether its on wail, yelp or hi lo. I checked everything and even replaced some of the connectors including the wire that runs from siren to motorola unit. I have to agree it sounds like a connection problem but but just cant seem to find it.

 

[TexasFireMedic]

I'd post up a video if you can

 

[Reno911]

siren always activates and never cuts off completely. Hard to describe almost like a continuous popping sound. Its not smooth sounding and its very noticeable whether its on wail, yelp or hi lo. I checked everything and even replaced some of the connectors including the wire that runs from siren to motorola unit. I have to agree it sounds like a connection problem but but just cant seem to find it.

I kind of have the same thing happening with some older FS100w siren speakers I have tested. Good FS Touchmaster and it sounds crackily on wail and PA sound is terrible.


Maybe the answer to your problem could help me too. Could it be the amp for the siren?

 

[TexasFireMedic]

Experience with pro audio is sending me a red flag that the diaphragm might have developed a flaw, Sam.


I found this document.


http://www.fedsig.com/docs/256571.pdf


Now, one of the prep steps listed involves confirming 4.2 ohms resistance cross the lugs on the driver. This is another red flag. Most siren speakers I've seen have an impedance of 11 ohms. That is a significant difference. I'd ask some of the more experienced members if your particular touchmaster model is designed for a low resistance speaker. I couldn't find any info online that stated a specified output impedance for these...

 

[Henry455]

Experience with pro audio is sending me a red flag that the diaphragm might have developed a flaw, Sam.

I found this document.


http://www.fedsig.com/docs/256571.pdf


Now, one of the prep steps listed involves confirming 4.2 ohms resistance cross the lugs on the driver. This is another red flag. Most siren speakers I've seen have an impedance of 11 ohms. That is a significant difference. I'd ask some of the more experienced members if your particular touchmaster model is designed for a low resistance speaker. I couldn't find any info online that stated a specified output impedance for these...

The confusion is the difference between RESISTANCE and IMPEDANCE. The speaker driver coil has a resistance of approx. 4 ohms and an impedance of 11 ohms Nominal, usually tested with a 1000 Hz tone. When dealing with speakers even though they are both measured in ohms they are not the same. To measure the driver resistance you can use a simple VOM, to measure the impedance you need different equipment including a tone generator. If you are measuring your drivers resistance at 11.4 and 9.5 ohms, something is wrong with the drivers.