I have seen some speakers with built in LED's that light up from the amp powering the speakers.
I am very interested in incorporating this into some designs and have not a clue where to start.
I'm assuming it is done by incorporating a small inverter circuit of some sort because I can not find ANY LED's that are made specifically to be powered by an audio amp.
Can anyone help??
I am very interested in incorporating this into some designs and have not a clue where to start.
I'm assuming it is done by incorporating a small inverter circuit of some sort because I can not find ANY LED's that are made specifically to be powered by an audio amp.
Can anyone help??
You could run the speaker line in parallel with the existing speaker through a low value (determine by experiment at maybe 15 ohms minimum and go higher as possible the better) to a bridge rectifier. Output of the bridge to an electrolytic cap and this power supply runs to the LED's through small current limiting dropping resistors. This will screw with the sound though, so why would you wanna?
If you want a light show from your speakers without extra electricity you could alternatively spray them with lighter fluid and set them on fire. This would not initially affect the tone as much as the LED power draw.
The second idea is not safe though and should not be attempted without a fire department pumper truck and crew standing by outside your house.
If you want a light show from your speakers without extra electricity you could alternatively spray them with lighter fluid and set them on fire. This would not initially affect the tone as much as the LED power draw.
The second idea is not safe though and should not be attempted without a fire department pumper truck and crew standing by outside your house.
umm...thanks...I guess!
While I will try that circuit, I know it is possible to do it without screwing with the sound.
I mean LED's draw hardly any power......
A 100 watt RMS amp shouldn't be affected what so ever nor should the
the sound of the speaker be compromised.
There are a number of woofers on the market with LED's inside of them.
Some even grow brighter from the music peaks.
Hmmmm, why would I want to do this?
Because it looks badass!!
I'm also working on engineering a speaker that I had created in a dream....they were really wicked man and maybe not COMPLETELY original, they would still be very unique
While I will try that circuit, I know it is possible to do it without screwing with the sound.
I mean LED's draw hardly any power......
A 100 watt RMS amp shouldn't be affected what so ever nor should the
the sound of the speaker be compromised.
There are a number of woofers on the market with LED's inside of them.
Some even grow brighter from the music peaks.
Hmmmm, why would I want to do this?
Because it looks badass!!
I'm also working on engineering a speaker that I had created in a dream....they were really wicked man and maybe not COMPLETELY original, they would still be very unique
no, you're not likely to hurt anything if
calculate your max amp power supply voltage
max current the led can take
and calculate a "safe" resistor.
consider can the led take the same as a reverse voltage?
or do you need a pair of leds parallel but (pos to neg)
now,suspect this won't light often so you will likely lower the value-how long can your led stand it when you crank it up is the question?
search for schematics of drivings leds directly from mains
they have some techniques that may be useful
having fun is part of diy
calculate your max amp power supply voltage
max current the led can take
and calculate a "safe" resistor.
consider can the led take the same as a reverse voltage?
or do you need a pair of leds parallel but (pos to neg)
now,suspect this won't light often so you will likely lower the value-how long can your led stand it when you crank it up is the question?
search for schematics of drivings leds directly from mains
they have some techniques that may be useful
having fun is part of diy
Powered by the output?
Are you thinking of a power meter?
An LM3914/3915 can do that.It samples the output and has built in comparator and LED drivers.. I don't think I've ever seen a meter like that powered straight from the output. 😕
Are you thinking of a power meter?
An LM3914/3915 can do that.It samples the output and has built in comparator and LED drivers.. I don't think I've ever seen a meter like that powered straight from the output. 😕
But I have ! There was once a stereo System by ITT (manufactured by Mitsubishi and labelled ITT actually) at the end of the seventies. These were supplied with large speakers (built with SEAS drivers and sporting a 12" woofer) that actually had a power meter on their front which was powered by the audio signal !
Regards
Charles
I think there are even a couple of kits that do this in the form of a VU meter. Velleman probably. Check out www.qkits.com, I think I saw one there If you don't want the bar graph format you could still midify the kits by running leads from the pcb to wherever you want the LEDs to be located.
A VU meter is much better off being an active circuit and having its own power supply, or power in the form of AC signal can be run to the speaker boxes (Requires 2 more conductors) which can drive an LM3914/3915 IC to make a completely conventional VU meter which will have no impact on sonic performance.
To actually power the LEDs from the amp output WILL have an effect on sound output. Even with a limiting resistor to keep the current going through the LED to a few mA, the problem is that the load represented by the LED is variable, which will introduce distortion to the loudspeaker.
If you were to run say 16VAC alongside your speaker wire (Since this is only going to need low current this is unlikely to introduce any audible noise) you could run that to a voltage doubler, rectify, regulate and filter it to give you a +/-15VDC supply, which could then be used to power a VU meter. Alternately, you could give each speaker box a wall wart to supply power to a VU meter.
IMHO, this is a much better approach, and gives you much more flexibility.
To actually power the LEDs from the amp output WILL have an effect on sound output. Even with a limiting resistor to keep the current going through the LED to a few mA, the problem is that the load represented by the LED is variable, which will introduce distortion to the loudspeaker.
If you were to run say 16VAC alongside your speaker wire (Since this is only going to need low current this is unlikely to introduce any audible noise) you could run that to a voltage doubler, rectify, regulate and filter it to give you a +/-15VDC supply, which could then be used to power a VU meter. Alternately, you could give each speaker box a wall wart to supply power to a VU meter.
IMHO, this is a much better approach, and gives you much more flexibility.
Re: umm...thanks...I guess!
Sure and folks here who are after the highest possible sound quality are flocking to these in droves because the added LED's show clearly that much emphasis was placed on making the driver top notch sound quality.
I have a pair of Sansui SP9393 kabuki type speakers in the lab that I use as dummy load for amp testing. I didn't pay any money for them. Anyhow, they have built in LED power meters that ramp up as the speaker gets driven harder.
This all reminds me of how the Europeans gave shiny trinkets and mirrors to the North American Native Indians in exchange for goods of actual value when they arrived on our shores not so long ago.
MrCheeks said:
Sure and folks here who are after the highest possible sound quality are flocking to these in droves because the added LED's show clearly that much emphasis was placed on making the driver top notch sound quality.
I have a pair of Sansui SP9393 kabuki type speakers in the lab that I use as dummy load for amp testing. I didn't pay any money for them. Anyhow, they have built in LED power meters that ramp up as the speaker gets driven harder.
This all reminds me of how the Europeans gave shiny trinkets and mirrors to the North American Native Indians in exchange for goods of actual value when they arrived on our shores not so long ago.
Sounds very appropriate to use with an overclocked tricked out gaming PC. I'm thinking of the ones with a windo case, bubble lights, cold cathode UV illumination, wild paint etc, etc. Have the speakers flash at you every time you blast an evil-doer! In this application I wouldn't worry much about the sound quality.
For listening to real music, I even wory about the effect of an active VU on the amp. Probably no need to, but I tend to be an "audio-condriac" at times.
Lets be conservative and say we have 3Amps rms pumping thru
our unique woofer.
the 20ma or so to drive the led introduces how much distortion?
in a sub or woof?
If enthusiasm for a project can create an interest in electronics
and or audio then I would encourage them.
If they stick around they will learn abound the finer points...
our unique woofer.
the 20ma or so to drive the led introduces how much distortion?
in a sub or woof?
If enthusiasm for a project can create an interest in electronics
and or audio then I would encourage them.
If they stick around they will learn abound the finer points...
Davesaudio,
Good points. Plus, taking a quick tour through published specs, one sees very few subwoofer amps with distortion figures that would put them is the same category as main amps. I also have read somewhere (soory I can't cite it) that we tend to be less sensative to distortion at low frequencies. As you say it seems dubious that a few LEDs in parrallel are going to make a difference anyone but the platinum-eared will hear.
Good points. Plus, taking a quick tour through published specs, one sees very few subwoofer amps with distortion figures that would put them is the same category as main amps. I also have read somewhere (soory I can't cite it) that we tend to be less sensative to distortion at low frequencies. As you say it seems dubious that a few LEDs in parrallel are going to make a difference anyone but the platinum-eared will hear.
conservatively 3A RMS continuously trough my woofer would mean about 115 dB/1m or so. this will cause remaining hear damage after about 30 seconds.
i did a quick measurement, at the monent i´m listening with peaks at ~15mA
Did any of you think about the LED is not linear, but something like a switch that shorts against the series resistor when reaching a voltage threshold?
ok, i wired a LED across the speakers, but it did not light up. voltage too low..... would need to go and use ear protection to try at higher levels.
Did any of you think about the LED is not linear, but something like a switch that shorts against the series resistor when reaching a voltage threshold?
ok, i wired a LED across the speakers, but it did not light up. voltage too low..... would need to go and use ear protection to try at higher levels.
Let's say the sub has an impedance of 4R (forget that it's varies with f). And lets say you use the LED in series with a 1kR resistor which are parallel to the sub. When the LED switches on the impedance seen by the amp drops from 4.00R to 3.98R. Will this be audible? Maybe, but I suspect not by many people. As far as diode switching transients go chances are a sub won't respomd to them at all.
so you want to drive a 20mA LED with series 1k. Some Volts get lost in the LED, 2 or so. You need additional 20 Volts across the resistor.
Your woofer does see 22 Volts in 4 ohm to give the nominal 20mA for you LED. ..
Of couse this will work for boombass at disco levels, and for bad quality low efficent woofers producing crap and not music. Go, try it and be happy.
The better the speakers is, the more your LED in parallel turns into a distortion generator, as you need a lower series R for it.
Your woofer does see 22 Volts in 4 ohm to give the nominal 20mA for you LED. ..
Of couse this will work for boombass at disco levels, and for bad quality low efficent woofers producing crap and not music. Go, try it and be happy.
The better the speakers is, the more your LED in parallel turns into a distortion generator, as you need a lower series R for it.
Let's not forget. LEDs are DIODES. I wouldn't have even considered putting one in SERIES with the woofer, but I guarantee you that'll generate distortion. I was thinking MAYBE with a resistor and put it in parallel with the woofer...
Well, there's nothing like an experiment. I have an old woofer in my basement that I can try with and without an LED in parallel with it. I'm not exactly a "platinum ear" but I'm no "tin ear" either. I'll give it a try and see what the results are. I expect that there will be artefacts injected into the sound, but I'm willing to give it a fair shake.
Well, there's nothing like an experiment. I have an old woofer in my basement that I can try with and without an LED in parallel with it. I'm not exactly a "platinum ear" but I'm no "tin ear" either. I'll give it a try and see what the results are. I expect that there will be artefacts injected into the sound, but I'm willing to give it a fair shake.
But Till, you are coming from a high-efficiency-horn-enthusiast
type perspective- no?
low efficiency does not alway mean low quality IMHO
My take is that he is likely a disco or megawatt car dude
so I think my assertions hold true.
IF he hears a difference in sound you have won him over -no?
so the experiment has value in both cases
😉
nobody remembers being a teenager?
type perspective- no?
low efficiency does not alway mean low quality IMHO
My take is that he is likely a disco or megawatt car dude
so I think my assertions hold true.
IF he hears a difference in sound you have won him over -no?
so the experiment has value in both cases
😉
nobody remembers being a teenager?
wow you guys stumbled onto something else for me!
If the diode will cause distortion at higher levels, with the right amount of effort put into the circuit and my choice of LED, I may be getting a similar affect like when a tube amp over drives the power tubes and distorts.
The speakers I hope to use such a circuit for are in fact guitar speakers.
I have a VERY long way to go for I want to build my own woofer and likely will use a clear poly cone.
I don't want to give away too much but if all goes well my amp designs and this speaker design should realy make an impact on guitarists obsessed with tube amps, opinions on solid state.
Keep the information flowing if you can guys, it's helped quite a bit.
I am a novice but hopefully I can manage to at least get to the point where I am lighting the LED efficiently without any major compromise to the sound quality.....anyway, generally the modern guitarist is already using a high gain distorted signal as is.
If the diode will cause distortion at higher levels, with the right amount of effort put into the circuit and my choice of LED, I may be getting a similar affect like when a tube amp over drives the power tubes and distorts.
The speakers I hope to use such a circuit for are in fact guitar speakers.
I have a VERY long way to go for I want to build my own woofer and likely will use a clear poly cone.
I don't want to give away too much but if all goes well my amp designs and this speaker design should realy make an impact on guitarists obsessed with tube amps, opinions on solid state.
Keep the information flowing if you can guys, it's helped quite a bit.
I am a novice but hopefully I can manage to at least get to the point where I am lighting the LED efficiently without any major compromise to the sound quality.....anyway, generally the modern guitarist is already using a high gain distorted signal as is.
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