kelvinmead Posted March 29, 2013 Share Posted March 29, 2013 I have a query from the more knowledgable out there... I have some 2000w amps, stereo 2 channel, pretty industry standard things, driving all sorts, but looking directly at the fane collosus 18xb sub bass speakers. These are rated 800w, 8 Ohm (3200w max) which technically equates to a usual of 80v and 160v max, 20amps. If I was to wire a circuit, lifting power from the terminal outputs (very low usage, 3.3v, 40ma), would I see any difference in the speakers / sound / clarity Link to comment Share on other sites More sharing options...
david.elsbury Posted March 29, 2013 Share Posted March 29, 2013 What are you wanting to try and do with this 3.3v? Sense circuit of some sort? Link to comment Share on other sites More sharing options...
laolu Posted March 29, 2013 Share Posted March 29, 2013 If I was to wire a circuit, lifting power from the terminal outputs (very low usage, 3.3v, 40ma), would I see any difference in the speakers / sound / clarityNo. - If I understood you correctly. Whatever circuit it is you want to connect (optocouplers?) can easily be driven by the amps you mention without any audible influence on sound. Link to comment Share on other sites More sharing options...
Mixermend Posted March 29, 2013 Share Posted March 29, 2013 Important to describe what you are trying to do - as deriving power from the speaker signal is fraught with problems. With no signal present - nothing can be produced, then all of a sudden - you have a massive transient peak voltage to deal with.....If you are needing to remotely monitor signal output - this will certainly be possible, but will need careful circuit design.More information please! Link to comment Share on other sites More sharing options...
kelvinmead Posted March 29, 2013 Author Share Posted March 29, 2013 it occurs to me that when a large room speaker goes down, unless you specifically go looking for it, you wouldn't notice... not until a few speakers go down that is... im adding a tiny ir sender direct onto the speaker outputs, lifting the 3.3v, and when the speaker is activated the ir signal is sent, received and then portrayed somewhere sensible. probably going to use an attiny13, for the processing, and then either arduino [ease] attiny13 raspberry pi [networking] for the receiving of signal and display Link to comment Share on other sites More sharing options...
themadhippy Posted March 29, 2013 Share Posted March 29, 2013 One slight flaw in our plan,it only lets you know theres a signal upto the speaker,if the fault is inside the speaker it wont tell you becuse as far as its concerned theres still a signal,also it sounds a very complicated method to do a job that already has a device perfect for the job,ears Link to comment Share on other sites More sharing options...
Brian Posted March 29, 2013 Share Posted March 29, 2013 So let me get this right... the units you are connecting to the speakers are powered by the audio signal - hence the need to derive 3.3V. When they see audio they transmit an "I'm OK" signal. When the master unit fails to see an "OK" signal from a specific unit it assumes it must be faulty. Sounds feasible except, as Mr Mad Hippy says, the single most common fault with speakers is that the voice coil burns out which your system won't detect. Your better bet is to power the units as you currently plan to and then sense the current flow into the speaker box with a current transformer. Link to comment Share on other sites More sharing options...
Simon Lewis Posted March 29, 2013 Share Posted March 29, 2013 Voice alarm systems use an ultrasonic signal played through the speaker, then detected by a microphone to demonstrate that the speaker and speaker circuit is functional. Link to comment Share on other sites More sharing options...
kelvinmead Posted March 29, 2013 Author Share Posted March 29, 2013 So let me get this right... the units you are connecting to the speakers are powered by the audio signal - hence the need to derive 3.3V. When they see audio they transmit an "I'm OK" signal. When the master unit fails to see an "OK" signal from a specific unit it assumes it must be faulty. Sounds feasible except, as Mr Mad Hippy says, the single most common fault with speakers is that the voice coil burns out which your system won't detect. Your better bet is to power the units as you currently plan to and then sense the current flow into the speaker box with a current transformer. yeah, thats the brunt of it! ok, but there must be some change in the power used between a good speaker and a broken one... fortunately, I have a few burned cones to test with. I can always tweak the code to take a test of the current flowing, and then output a different ir code depending. Voice alarm systems use an ultrasonic signal played through the speaker, then detected by a microphone to demonstrate that the speaker and speaker circuit is functional. I like that system, but I can see it flawed in mic setup / speaker position Link to comment Share on other sites More sharing options...
Simon Lewis Posted March 29, 2013 Share Posted March 29, 2013 1364581938[/url]' post='469173'] I like that system, but I can see it flawed in mic setup / speaker position It's used in a variety of commercial systems, not just for voice alarm but also paging and background music. Link to comment Share on other sites More sharing options...
Brian Posted March 29, 2013 Share Posted March 29, 2013 ok, but there must be some change in the power used between a good speaker and a broken one... Yes, there is. BUT power is the product of voltage and current. You are only measuring the voltage. Link to comment Share on other sites More sharing options...
Jivemaster Posted March 30, 2013 Share Posted March 30, 2013 Wire the speakers in three core,1/ amp to speaker 12/ amp to speaker 23/ sense terminal to speaker 1 At the amp refer the sense wire to the speaker 1 wire to get an indication of current flow by measuring the volts drop down the speaker 1 wire. Link to comment Share on other sites More sharing options...
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