Is connecting an LED to a home theater system safe for the speakers/resistor/LEDs?

[ThorntonJ]

this is my first and possibly only post so please excuse me if im posting in the wrong area.

I am ALMOST a total novice when it comes to each of the components inside the hardware, but the hardware itself... i am a total geek, whether i look it or not.

i have been looking to pimp my home theater system, and my gameing computer speakers, both, by adding appropriate colored LEDs behind the speakers, and inside the subwoofers.

more recently i have been looking into this, and have been getting allot of mixed messages on the possible outcomes of doing this.

-some people say that you dont need a resistor (i know thats not true).

-some people say that all you need to do is add a resistor (but fail to mention the ratios to your sound system).

-some people are saying that it should not be done at all and the best rout to go is to make (a more expensive) color organ.



but my problem with all of these, is they are connecting the resistor to the LED, and then the -, and +, leads to the -, and +, behind the speaker. then people complain it draws power from the speaker...

could i just connect the - lead to the + clamp on the back of the speaker, and the + lead back to the wire leading back to the amp? this wont reduce the voltage or amperage going to the speaker, but rather to the amp its self... in theory anyways.


like i said, i dont do electronics, the most ive ever done was connect a computer fan to a 9v battery to see if it was the fan or the computer having problems. so the more detailed you can make your explanation, the more it will help me.

EDIT** i should say, i dont mess with wires... i build computers so i am kinda into electronics lol


P.S.

the basssubwoofer i plan to connect the LEDs to is 70watts, 120volts, and 60hz.

the home theater system, i have no clue, it is an LG LHT854

 

[circuitspecialists]

LEDs will not withstand much reverse voltage so I doubt your idea will work very well, since the audio signal is AC (both positive and negative polarity). Also except for very low frequencies you won't see much activity on the LED.

 

[KJ6EAD]

The only way you should connect an LED to your system is through a headphone output or line output or from a speaker output to an opto isolated input and to do that safely you need some circuitry like a color organ or sound to light unit. To do otherwise invites damage to the system.

If I wanted to "pimp" a system like that, I would build a bunch of simple microphonic sound to light units and add a filter to each to make it more sensitive to whichever speaker it was going with. The only connection to the system would be air.

 

[hexreader]

Adding an LED to your speakers will degrade the quality of your audio, but possibly not so much that an untrained ear will notice the difference.

Do you really need LEDs that badly that you want to risk accidental damage to your system?

But if you don't mind taking a risk with possible damage to your system, then I would guess that your amplifier will probably cope with the abuse that you intend.

Your choice, and entirely at your own risk, but I would recommend not messing with a working design.

 

[ThorntonJ]

Adding an LED to your speakers will degrade the quality of your audio, but possibly not so much that an untrained ear will notice the difference.

Do you really need LEDs that badly that you want to risk accidental damage to your system?

But if you don't mind taking a risk with possible damage to your system, then I would guess that your amplifier will probably cope with the abuse that you intend.

Your choice, and entirely at your own risk, but I would recommend not messing with a working design.

thats kindof why im here... as a gamer enthusiast... computer builder/ designer... 9 year 3d designer and 14 year 2d designer... things like this MORE than interest me.

i have prety sensitive ears, so much so that ive found going between 2 different FM stations sometimes gets me better sound quality on my home theater when im listening to music...

i want to play around with the concept a little. organs can be costly and the wrong shape for where im putting it, but i may be able to learn how to make one in time (unless its super easy and can be explained or googled, in which case sooner is better than later).


i unfortunately have a hard time with arguments like, "do you really need"... because i got that one for when i was looking into 23" 120hz monitors. people told me that people cant see the difference, and asked me if the box that says its 120hz was worth the extra 200 dollars. my answer was yes, because i see at about 20/20 and i can easily spot a 120hz monitor without needing a side by side. so the argument "do you reallly need" doesnt really sit well with me that often.

does anyone maybe know of an organ that i can attatch directly to my speaker, or the audio in? i dont like mics, there is a lot of polution in my house from dogs that will make the thing light up like a fire cracker, i know, ive tried them


i should add that i am partial to cold cathodes and if there is an organ i can plug directly into my audio that is a C. cathode, i would be on it in a heart beat

 

[hexreader]

So take your own risks, and reap your own rewards.

Nobody will tell you that what you propose is 100% safe, if that is the reassurance that you wanted.

Experiment, learn, and report back.

You seem to want more from the forum than the forum can give IMHO.

Given a choice between connecting to audio in, and speaker, I would go for audio in (with electrical buffering), as this will have full audio information.

I would follow the advice of KJ6EAD. I sense that he knows what he is talking about

 

[ThorntonJ]

i think my question has prety much been answered, to be clear, by safe, i know everything has risks, its the same in building and moding computers, i think what i was looking for was if the risk was one i really needed to be concious of, and if it had clear consequences that could be easily avoided. it sounds like they can be avoided by completely changing the method of creation. i will research more, and experiment with some other ideas. thanks for the help...



if anyone knows of a pre made organ i could buy, prefferably that runs an led strip, or preferably C. Cathods, than i would appreciate it.

 

[KJ6EAD]

You can use the Velleman MK114 to drive LED strips or CCFLs which they also sell. The MK114 is a kit but it's an easy one. It connects to the speaker via an opto isolator so it won't damage your system.

**broken link removed**

**broken link removed**

 

[unclejed613]

adding LEDs to the speaker outputs on an LHT854 won't degrade the sound noticeably. if you look at the spec sheet, distortion specs aren't even listed, so it's probably between 1 and 10%. (edit: in the service manual it says 10% THD at rated power of 155W/ch)
you don't want to connect between a speaker line and frame ground, as they are bridged outputs with 1/2 the output stage Vcc appearing on them. (it's a class D bridged amp)

i use 8 ohm test loads with a dual color (red/blue) signal indicator. the series resistor is 30K/2W, and the LED is a common cathode. the steering diodes are a TO-220 common anode rectifier wired directly in parallel with the LED (you can also use a pair of 1N4004 diodes). i'll post a schematic later if you want one, it's really a very simple device. i also use something similar to indicate DC offset (the device is built into a pen body) when troubleshooting receivers. it's a lot faster than a meter, and indicates red for positive, blue for negative, as a signal indicator it's purple when an audio signal is applied.