TIP31 feeding about 25 leds (audiorhytm circuit)

[Audioguru]

I have my stereo playing and have my Sound Level Indicator project flashing its LEDs to the sounds of music. It has a microphone and picks up all sound frequencies. Set for DOT mode then only one LED is on at a time. If I look at only one LED near the top (fairly loud sounds) then it lights briefly only during low frequency drum beats. When turned up louder then this LED also lights with low frequency bass sounds.

The circuit has an opamp peak detector/rectifier with a very fast rise-time and a fairly slow fall-time of 100ms. The fall time is slow enough (>30ms) so that short duration sounds are seen at full brightness but is fast enough for all multiple fast beats to be seen. The peak detector circuit feeds the comparators in the LM3915 LED driver IC.

Right now Justin Bieber (a Canadian like me) is singing his song "Sorry" and the top LED is showing the bass beat: boom, ba-boom, boom, ba-boom, boom, ba-boom, boom, ba-boom. So I think the rise-time and fall-time should be in the peak detector/rectifier that feeds the comparator. The comparator or another opamp can buffer the high resistance for the fall-time and can drive a Mosfet or power transistor that lights the LEDs. I think an opamp is better than a comparator since it has plenty of going high output current for a fast rise-time.

 

[Johanx2]

On the other hand, do you guys know if is it possible to pair two bluetooth sources, as for example, 2 bluetooth microphones, which I think they do exist, not sure, I was thinking about if it will be possible to connect two audio sources to my amplifier board? this would be a nice feature of my speaker box, I also thought about having several bluetooth modules inside, so you can pair several emitting sources, and have there a simple mixer before preamp, now I am not talking only about my circuit board, which stills its not arrived , but future amplifier boards, even without bluetooth built in, whichs not a problem since there are some ebay selles who sell discrete little bluetooth 4.0 modules at unbeatable price, the only problem may be the two signals having the same manufacturing name, which would be an undesirable problem.

I have noticed an important increment of technology on online stores, not only more things, but and unbeatable prices as never before, surely is it true what they said! that singularity will be born in about 3 more decades, transhumanism! I think I will turn even more nice once there is transhumanism market outside, you both are coolest now.

 

[Audioguru]

You can have many Bluetooth transmitter and receiver pairs operating at the same time. I do not remember how you program each pair to be together. Then a bunch of receivers can feed an audio mixer that feeds an amplifier. You would need to cut the pcb traces on your amplifier board to be fed from a mixer but you do not have a schematic or a pcb layout to do it.

 

[Johanx2]

You can have many Bluetooth transmitter and receiver pairs operating at the same time. I do not remember how you program each pair to be together. Then a bunch of receivers can feed an audio mixer that feeds an amplifier. You would need to cut the pcb traces on your amplifier board to be fed from a mixer but you do not have a schematic or a pcb layout to do it.

Yes, thats what I thought, however there would be something to consider, that there would be a minor problem if using the same bluetooth pcb boards manufacture, because surely all the Bluetooth devices will be signal labeled with same access point name, thats why I said that it would be a minor problem, unless you either modify the name of the transmitters or using different manufacture boards, so the speaker can be nicely transmit 2 different bluetooth point names if we are using two BT modules. Mixer is a minor problem, I have seen lots on the net, I can even buy the board from these guys that nowadays sell everything on electronics at unbeatable price, I took a look at the spectrum analyzers.

My pcb board still did not arrive, once I have it will take pictures with a magnifier lense, so I can share the pics and see what these guys have done with such a cheap product, will after all is a right price, considering it only can give 100w under very certain circumstances, you know, in my case I can not get 100 unless a wire a second subwoofer and down the impedance to low 2 ohms, with out mentioned the 10% distortion, which I think still is an interesting value on subwoofer frequencies.

 

[Audioguru]

Only a deaf person would turn up the volume too high so that the amplifier clips like crazy with 10% distortion. The datasheet for the Texas Instruments class-D amplifier IC shows that it begins clipping at about 50W or 60W into 2 ohms and shows 25W or 30W into 4 ohms. When an amplifier is clipping then it sounds something like a buzzer.

 

[Johanx2]

What do you guys think about my enclosure design?

It has the advantage that unless it is in vertical position, very voice speaker is where can offer interesting stereophonic sound in stead of everything in a front panel. left side is left mid and below we have the 8" driver, at the next right side we have the right speaker and the air port, subwoofer has its designed box chamber, and then I made another chamber, more discrete and sealed for the couple of little drivers will dont know how loud will be at mids, interesting thing that you turn down the subwoofer pot, then set mid pot, and then increase subwoofer pot until desire volume. upside will have a windows with potetionmeters, which will be in the board, but this board will be somehow attached to a wall, for resistant. Also I made some 1.5 holes around the air port, this port will have some led leds, but circles will have and acrilic with 3 screws and 3 leds, so a total of about 40 leds counting the green onces at the port holder. Woofer will have 36 leds aroundm an acrylic disc that willput in place a simple protective mesh, I put 8 screws in the led group, becase this box has some windows, I think I will put some green leds, also the panel where pots are, will be mounted in an acrylic rectangle, so you will ve able to see the interior, all made with 3/4 plywood. I will never use mdf and screwsm always give problems, so you are force to use dowels or box joints, which this last is the best thing you can do for a mdf ensloure, some box joins will make the structure act as one unique solid piece, I dont want to deal with that again, so will go for some plywood, wont be bad with a 8" driver, maybe is better than I need, but I get the advantages of screwing the screws without stripping anything. I can later put more features like the mixer or even a spectrum analizer by 8x8. Note that I am using 10mm leds, which I think will give a look with good density of points and leds blinking at the rhythm of bass, I think this time I am only flashing the leds by bass beats, as you can see I have been working in this enclosire, subowofer enclosure chamber has the correct amount space, so it will performance at its maximum possibilities, I think this is more that enough for a domestic music player, and because adding too much leds, It would be nice in a party, you will be able to diminish or turn off the leds, and well, this would be my first version of a enclosure musical box with built it components, I have never done something like this before. I know that image shows a technical drawing, I hope you understand the concept. Because every voyce speaker is located at different side, I think I will have interesting stereophonic effect, is this or having two boxes, which I dont want, although there is the option of everythin in the same face, but voice drivers lightly oriented to left right, I think I am going with this very sood. Still amplifier did not come, hope to start cutting the wood pieces soon. red circles are screws holding acrylic pieces, the leds are inserted drilling the surface and pastim then with some industrial glue, I would before sand paper them a little at the sides, so they will be glue permanently no matter what.

 

[c_mitra]

When an amplifier is clipping then it sounds something like a buzzer.

Very unkind comment. Most people cannot make out 10% distortion because our sensitivity scale is somewhat logarithmic- we can hear whispers and explosions but not at the same time.

- - - Updated - - -

What do you guys think about my enclosure design?

1. mdf is rather antiresonant- highly recommended for speaker enclosures.

2. I have not *yet* understood whether your LEDs are dancing to frequency or amplitude.

3. For a *real* stereophonic effect you need to have *real* physical separation. You can get away with simulated phase effects but they are *surreal*

 

[Audioguru]

Mid-tweeter speakers are directional at high frequencies so they must point directly at you. Your speaker mid-tweeters point to the sides instead then you will not hear the high frequencies properly.
Stereo has a speaker located at the left of you and another speaker at the right of you. Your speaker will not produce stereo.

- - - Updated - - -

Most people cannot make out 10% distortion

I disagree. Many people like high fidelity sound because it sounds real with low distortion and they can hear 0.2% distortion that sounds bad. Clipping distortion has added odd numbered harmonics that are very noticeable and un-musical. Most high fidelity systems have plenty of headroom so the amplifier never clips. Why play an amplifier with its level turned up too high so that it is clipping?

 

[Johanx2]

I think that of course it will produce stereo sound because it will have enough power to fill the room with waves half and half, left and right, specially if you move it so the corner faces you and correctly half the flow in front of you, and now the sound its more like, every speaker getting into different ear, of course the correct setting is having two boxes enough separated so the flow travels as, but for convenience, I am doing this, which dont you think is a lo better than placing all the drivers in the same face? I also wanted vertical the unit, to it save space.

I found so difficult to think you wont experience a stereo sound on this configuration, I agree that maybe not as good as one speaker pair, but definitely a lot more good that having both drivers in the same face with very little distance each other.

 

[betwixt]

The complication is to do with the phase of the sound waves. We perceive direction because our brains analyse the tiny time delay between the pressure waves arriving at one ear and the other. In a stereo recording, the microphones are positioned so they pick up sounds coming from the dominant direction our ears would hear and when played back using two speakers in a triangle configuration (listener is the third corner of the triangle) the phase is preserved. If you reproduce the sound from a single central position, even if the pressure waves are aimed in different directions, the phase information is lost. Yes, you still get the impression of the sound sources being in different space but the actual direction will not match the original recording positions. As C_mitra stated, you can to some extent 'spatialize' the sound by adding delays and subtracting one channel signal from the other but it creates a very false sound.

As far as distortion goes, I can very clearly hear distortion down to below 1%, it depends on the kind of distortion but clipping is one of the more obvious ones.

Brian.

 

[D.A.(Tony)Stewart]

Re: TIP31 feeding about 25 leds (audio RHYTHM circuit)

This design is poorly planned.
Audio signal is just the carrier wave. The rhythm you want is the modulation of the bass frequencies(LPF) and fast attack of the drums beat(HPF).

DEpending on the music, the carrier waves can be quite constant so there may be little or no flashing in spite of heavy metal rhythm

Thus we need to know what examples of music you play, how precise you want the rhythm tracking pulsed light to work (exactly). and what type of sounds it will ignore.

Thus the block diagram will be

DC and stereo signals> filter1> rectifier> filter2 > automatic or manual gain and dark reference adjust > LED driver> LEDS. > mono or,stereo?

All other attempts will be just bright LEDs with occasional flicker off in the quiet parts.

the rest of the discussion is " noise". This wont affect audio if specified properly above for the effects which ONLY you need to define "exactly"..

There are many choices and effects. But it seems you want a rhythm tracker with minimal delay and maximm punch of light.

p.s. I am not a dude
EE since 1975

 

[c_mitra]

Re: TIP31 feeding about 25 leds (audio RHYTHM circuit)

you want is the modulation of the bass frequencies(LPF) and fast attack of the drums beat(HPF).
1975

These modulations are subsonic; you need to preserve the modulations so that they are fed into the flashing LEDs.

On the other hand, all audible frequencies (20-20kHz) if fed into the dancing LEDs will be barely visible unless "the carrier" goes out...

But the real thing will be a console where you can design the display according to the music. What is needed is envelope detectors and ignore everything. The modulation of the bass frequencies and the fast attack of the drums beat are two different beasts altogether in my opinion...

 

[D.A.(Tony)Stewart]

Re: TIP31 feeding about 25 leds (audio RHYTHM circuit)

Any flicker needed must be subsonic but turn on /off rapid. This is the beat.
The beast is defining the user expected response. then the design for pros is trivial.

Otherwise dozens of more tangential queries may persist, "chasing skinny rats that escape into a hole"

 

[Audioguru]

Re: TIP31 feeding about 25 leds (audio RHYTHM circuit)

p.s. I am not a dude

Tony (or is it Toni?), sorry to go off topic a little. Your statement confuses me about your gender that is shown on some sites but not on this one.
I looked up "opposite of dude". If you are not a dude then are you a chick?
I also looked up the definition of "dude" is a cool guy. So then you are a hot chick?
Hee, hee.

 

[Johanx2]

Re: TIP31 feeding about 25 leds (audio RHYTHM circuit)

p.s. I am not a dude
EE since 1975

There is a third gender, maybe he/she is one of them, it does not matter here.

Damn, i am a little mad, the chinese manufacturer sent me an email telling me that there is a big delay on my item, and it's just now that they will be send it, so it will arrives in one more week! this turned me crazy, really, I then asked for a compensation, and they said, we can send it free and refund money, but still mad because I am not patient waiting, specially very long times, which is happening with this thing, anyway it seems they are going to send 2 items, and not refund me anything, thing I suggested, it seems they agreed.

talking about my left/right speakers, trust me I know that its not the best configuration, how ever I thikg its the best thing I can do if want stereo sound and don't want to put the 2 speakers in the same side, just like a compact cd player with speakers does, but you know, I still can think to put 2 little mid/high speakers in same side, bit changing a little its orientation, just by playing with the angles of the speakers seat, I mean, the upper one pointing a little to left, and right the opposite, subwoofer does not matter too much, maybe 2 voice speakers, and below the air port, and on the other side, the subwoofer driver, I will begin with the image I showed, and pretend to play and evolve future designs, because I not only consider esthetics but convenience, vertically in this case, and one voice speaker at one different side, al good volumes, I think we will get a type of good stereophonic effect, imagine 2 people groups, of course the group we is seating at the left furniture will notice when the only speaker right is the one which is emitting,. This is just the first model, I am planning making several forms, this one pointed for physic convenience, specially designed for putting it in a wall corner, being an only object, not two objects and one on every wall corner, this points to convenience and still god stereo effect accorded to the presented limitations. I dont thing to make soon systems where we will have 2 separated enclosures, in that case the second option would be an horizontal rectangle, in single piece made, whith a subwoofer at the center, that 2 voice high drivers located at left/right, lightly oriented to the left/side, for increasing the stereo effect (I took 2 minutes to draw this picture below), so for now I have three simple concepts, the first I showed which is vertical, the second being vertical as well, but all voice drivers at same face wall, but each one oriented a little left/right with the proper wood/mdf adapter cut, every one have its good and bads, for now I am going with first picture, voice driver pointed to south, and other one to west, ot will sound interesting specially at good potency in a party for example.

By the way, all the lights I think are going to be same time and only for bass beats, maybe latter work on something different. About wood, I will take the advice of using mdf, because its advantages, so now I am obliged to use 5/16 dowels or box joints, which I will use first one, because their practicality, I concluded some times that screws are only supported on the face of a mdf piece, but not on the edge, not even using special screws, which I think still is bullshit and that thin can rip with some stress, so this is a task for box joints or dowels.

Its nice

 

[c_mitra]

Re: TIP31 feeding about 25 leds (audio RHYTHM circuit)

I also looked up the definition of "dude" is a cool guy..

I too was ignorant about the word and I too looked it up on the online dictionary. As the word is American, I referred to dictionary.com and it says:

1. a man excessively concerned with his clothes, grooming, and manners.
2. Slang.
a fellow; chap.
b (a general term of address used to a man, woman, or group).

3. a person reared in a large city.
4. Western U.S. an urban Easterner who vacations on a ranch.

As it looks interesting, I also noted the etymology:

n.
1883, "fastidious man," New York City slang of unknown origin. The vogue word of 1883, originally used in reference to the devotees of the "aesthetic" craze, later applied to city slickers, especially Easterners vacationing in the West (e.g. dude ranch, first recorded 1921).

I learnt another gem: there is a version of English called "Black English"

The summary is that it has nothing to do with gender.

 

[Johanx2]

Well, seems cannot edit anymore. I am going to show the picture where I meant to put the 2 voice drivers on same face, lightly oriented to left/side, I think this should give good stereophonic effect at certain distance, and with the enclosure in that way, we have the advantage of space, although for placing it in a corner, I think the best is the first design I made, it and wont take any of your furniture than 10x10 inches of surface. I did squares because did not know how to do the same with circles xD, same difficulty when wood working on it I think.

 

[Johanx2]

Yes, you still get the impression of the sound sources being in different space but the actual direction will not match the original recording positions.
Brian.

At good intensity I am pretty sure that in theory will make sense a nice feeling of stereoscopic effect, trust me I will be happy just with that, I think for now I am happy with that because if one of the main characteristic ok the stereo audio, I want it a little far away fron a mono signal/sense. When this thing is at the corner of a wall, and there are two people, at the left and right, surely will be amazed with the effect, that put me more than happy if needed to keep a verticallity strccture.=, stereo sound, and And thats it!

 

[Audioguru]

I might finish this now:
"Originally Posted by SunnySkyguy

p.s. I am not a dude
EE since 1975"
DUDE: 1. a man excessively concerned with his clothes, grooming, and manners.
Therefore not being a dude makes a guy a slob?

Directional high frequency speakers should be pointed directly at the listeners, not to the sides.
A speaker sound that bounces off a wall or floor causes peaks and nulls at various frequencies due to the different distances (delays) changing the phase.
Real stereo with left and right speakers pointing directly at you makes a big improvement to music. Your speaker will sound the same as mono.

 

[c_mitra]

at the left and right, surely will be amazed with the effect, that put me more than happy if needed to keep a verticallity strccture.=, stereo sound, and And thats it!

Absolutely correct! You can get *correct* stereophonic effect only at one *correct* position of the speakers and the listener. Fortunately the recording standards are more or less standard (few follows it) but the playback is yours and you only decide.

The original was probably recorded on several microphones, sometimes more than six, mixed by another engineer and finally recorded as L+R and L-R signals on a file. You are anyway hearing what they want you to hear. If you think that you are hearing what you would have been hearing if you were in the middle row in the theatre then you are very likely mistaken.