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Electronic sirens and dual tone...
Posted: Tue Jul 14, 2009 7:25 am
by md5
Mainly in reference to this youtube link recently posted:
http://www.youtube.com/watch?v=yc-mIy3nCm4&fmt=18
If i am not mistaken, it causes a bit more stress on speaker coils to produce a dual tone / multi tone sound rather a single tone.
I'm not sure if this can be done at all, just speaking out of mind. On modulators and other electronic sirens, such as whelen's. Is it possible to set one group of speakers to the higher tone and the other remaining set of speakers to the lower tone? However, would that cause sound cancellation? More or less, if it's possible - has such a thing been done?
For example, lets say we have a Federal Signal Modulator MOD6048 in use. The top three speakers would be producing the higher tone, while the bottom three would be producing the lower tone. Would that cause less stress to an electronic siren when in 'dual tone'?

Posted: Tue Jul 14, 2009 8:51 am
by CJ
I think it's been done before, and hell yes it would definitely reduce the stress put on the drivers.
But you would need two seperate tone generators.
Posted: Tue Jul 14, 2009 9:06 am
by md5
CJ wrote:I think it's been done before, and hell yes it would definitely reduce the stress put on the drivers.
But you would need two seperate tone generators.
Since most stuff now a days (eyeing the FS2001 control board) is digital and so on, would it just need an additional "sound out" line for the second set while keeping a single tone generator?
Posted: Tue Jul 14, 2009 9:38 am
by CJ
md5 wrote:Since most stuff now a days (eyeing the FS2001 control board) is digital and so on, would it just need an additional "sound out" line for the second set while keeping a single tone generator?
They would need to slightly restructure the tone generator - currently it makes 2 tones that are synchronised (attack cycle etc.) They could possibly redesign it so that one of the tones is given to one output, for a set of amplifiers, and the second tone given to the other set of amplifiers.
However, i'm not too sure how much of a restructure that would take - quite possibly it would actually need to redesign it completely.
Posted: Tue Jul 14, 2009 10:51 pm
by EL1998P71
Carson Sirens for 12 volt sytems (police cars, ect) produce two different tones at the same time thru one speaker (100Watt)
So I would think that there's a way to run dual tones without destroying the drivers.
I'm not sure on whelen's or Modelualtors.
Posted: Tue Jul 14, 2009 11:25 pm
by Jim Z
multitones are no more stressful than a single one, provided:
1) the RMS power of the multitone is within the speaker's capability
2) neither of the component tone frequencies are below the speaker's design limit.
Posted: Wed Jul 15, 2009 12:18 am
by JasonC
CJ wrote:I think it's been done before, and hell yes it would definitely reduce the stress put on the drivers.
Two tones or 100 tones are not going to hurt or stress a speaker as long as they are within the conditions Jim Z stated above.
There is really no advantage to separating the tones through different speakers. It can be done, and as long as the tones were phased right and the speakers set properly, there would be no concern of cancellation. And as far as redesigning the tone generator to do this, it would probably be no more than swapping a couple of wires around (to drive two separate amps) and that's it.
Posted: Wed Jul 15, 2009 12:50 am
by SouthDakotaBoy2009
precisly, like the speaker drivers of Federals state it can be set to any hz tone as long as its in between 2000hz & 200Hz, go over & or too low & you start to ruin it.
Posted: Wed Jul 15, 2009 2:17 am
by JasonC
EL1998P71 wrote:Carson Sirens for 12 volt sytems (police cars, ect) produce two different tones at the same time thru one speaker (100Watt)
So I would think that there's a way to run dual tones without destroying the drivers.
I'm not sure on whelen's or Modelualtors.
Are you sure? I used to run an SA-441 Magnum (actually it was a Star SS-741 before they switched names) siren and each speaker did a separate tone than the other speaker when in magnum mode. Each speaker had it's own separate connection to the remote amp. Good siren though.
Posted: Wed Jul 15, 2009 2:30 am
by Whelen4004
hmmm.... My Grandma has a modulator and last time we Had bad storm it did the Same style of Alert as This modulator.... ill get a video of it next time im there on a saturday