Hello boys and girls. Newbcake here! Came across this wonderful forum and am here to learn!
I want to create a portable boombox from PIPES and used 2.1 speakers that is loud and efficient(YouTube 2.20 mark but with a woofer from the 2.1). I have been doing research for a week now and honestly, the more I read the more I realise how complex and subtle speaker making actually is. So onto the point.
I want to make a speaker that will work primarily as a portable boombox but will also function as my home speakers when not on the road.It must be able to power from powergrid and charge at the same time. My budget is very limited and apart from the new amp that I will buy(class-D) most will be 2nd hand parts. The idea is to use PVC pipe that is roughly 7 inches(17-18cm) in diameter which will be able to strap onto my backpack and provide tunes for our whole group. My guess is 1 T shaped unit to house the woofer and 2x90 degree bends for the other drivers. But here i rely on your expertise. Should it be ported, sealed or with passive radiator?
This is the video which inspired me YouTube and in it(around 3min,20sec mark) the guy says it is possible to make the stero signal Mono and then double amplify the bass by running it through the amp again. Is this possible and how because his explanation is above my skill level even though I am a quick study this will be my first electronics project ever.
Is 2x15 amp enough? How should i go about the construction of the case if it is even viable? How to get the maximum out of such a system?
Forgive my noobishness. I am extremely excited about this and am willing to learn w/e you guys throw at me.
Help me bring the joy of Black Sabbath to unsuspecting wildlife!
I want to create a portable boombox from PIPES and used 2.1 speakers that is loud and efficient(YouTube 2.20 mark but with a woofer from the 2.1). I have been doing research for a week now and honestly, the more I read the more I realise how complex and subtle speaker making actually is. So onto the point.
I want to make a speaker that will work primarily as a portable boombox but will also function as my home speakers when not on the road.It must be able to power from powergrid and charge at the same time. My budget is very limited and apart from the new amp that I will buy(class-D) most will be 2nd hand parts. The idea is to use PVC pipe that is roughly 7 inches(17-18cm) in diameter which will be able to strap onto my backpack and provide tunes for our whole group. My guess is 1 T shaped unit to house the woofer and 2x90 degree bends for the other drivers. But here i rely on your expertise. Should it be ported, sealed or with passive radiator?
This is the video which inspired me YouTube and in it(around 3min,20sec mark) the guy says it is possible to make the stero signal Mono and then double amplify the bass by running it through the amp again. Is this possible and how because his explanation is above my skill level even though I am a quick study this will be my first electronics project ever.
Is 2x15 amp enough? How should i go about the construction of the case if it is even viable? How to get the maximum out of such a system?
Forgive my noobishness. I am extremely excited about this and am willing to learn w/e you guys throw at me.
Help me bring the joy of Black Sabbath to unsuspecting wildlife!
"it isn't a particular elegant method" to take the output form the amplifier and then route it to the input. As the amplifier has two channels...
It is common to use one channel for mid/treble and the other for bass but with regular inputs that are filtered for the purpose.
Usually, on a mid/treble channel you won't fine much bass frequencies ( they have been filtered out ) so you won't get any " extra strenght" signal if your purpose is to have more bass. I mean, the way this guy does it , it works but... also the transformers at the input are rarely seen in our equipment.
A 2.1 board ( 2 regular channels plus 1 more channel for the subwoofer, usually double power ) does it all and doesn't require mono for L and R ( which wouldn't exist differentiated...) and it does the job of mixing them ( yes, two resistors plus some active circuitry ) and sending the low-passed signal to the amplifier ( for sub ).
The enclosure is another matter
It is common to use one channel for mid/treble and the other for bass but with regular inputs that are filtered for the purpose.
Usually, on a mid/treble channel you won't fine much bass frequencies ( they have been filtered out ) so you won't get any " extra strenght" signal if your purpose is to have more bass. I mean, the way this guy does it , it works but... also the transformers at the input are rarely seen in our equipment.
A 2.1 board ( 2 regular channels plus 1 more channel for the subwoofer, usually double power ) does it all and doesn't require mono for L and R ( which wouldn't exist differentiated...) and it does the job of mixing them ( yes, two resistors plus some active circuitry ) and sending the low-passed signal to the amplifier ( for sub ).
The enclosure is another matter
Thank you for the quick response!
The way i understand it the 2.1 boards use more power than regular 2channel.
Also since on a project this size and use conditions stereo isnt needed his idea seemed useful for my implementation purposes.
Also the boards I have access to are all dual channel. Specifically this one TDA7492 2x50W Google Image Result for https://www.winddeal.net/image/28406/1.jpg
My research shows this board delivers around 20W+ of clean power when ran at proper voltages.
I just need to know how to create this 2.1 mod and the best way to construct the enclosure for maximum bass.
The way i understand it the 2.1 boards use more power than regular 2channel.
Also since on a project this size and use conditions stereo isnt needed his idea seemed useful for my implementation purposes.
Also the boards I have access to are all dual channel. Specifically this one TDA7492 2x50W Google Image Result for https://www.winddeal.net/image/28406/1.jpg
My research shows this board delivers around 20W+ of clean power when ran at proper voltages.
I just need to know how to create this 2.1 mod and the best way to construct the enclosure for maximum bass.
Hi, after the "2.1 mod" for mono you'll get 1.1 channels 
I tried this way : with a stereo board and both inputs connected together, so a mono signal driving them and at the outputs the signal is passively low-passed (a coil) in one channel then goes to the woofer and the other channel drives a small wide band speaker with a high-pass in between (a capacitor).
I tried this way : with a stereo board and both inputs connected together, so a mono signal driving them and at the outputs the signal is passively low-passed (a coil) in one channel then goes to the woofer and the other channel drives a small wide band speaker with a high-pass in between (a capacitor).
Hi, after the "2.1 mod" for mono you'll get 1.1 channels
I tried this way : with a stereo board and both inputs connected together, so a mono signal driving them and at the outputs the signal is passively low-passed (a coil) in one channel then goes to the woofer and the other channel drives a small wide band speaker with a high-pass in between (a capacitor).
Thank you Pico! I will try it your way as well.
I found some specs for the 2.1 speakers I am going to use. In your opinion is the amp mentioned in my first post adequate for this purpose or something like this is more applicable? OEP30Wx2 Audio Module Class D Digital Power Audio Amplifier ReplaceTDA8932 ATF | eBay
Since i've created the post I learned a lot and am currently learning winISD as well in attempt to figure out how the woofer enclosure should be made. The end result should be in the line of this. Just variable dimensions.
Google Image Result for https://i.ytimg.com/vi/yUAzymwMFfU/maxresdefault.jpg
Hmmm ( hi ) let's talk about batteries !!
Some AA batteries won't make anything. If you want power.
I feel that those tiny amps won't make anything too; you know, seeing
the heatsink attached to the transistors and feeling it warm or hot is how some senses ( sight and touch ) feel...the power ! Nowadays class D amplifier have more than 90 % efficiency compared to 40-50 % of class B or AB amplifiers, and the heat is a sign of power transformation ( loss ).
So you still would want big batteries and little power loss ( uhm, ok: speaker's efficiency usually is less than 1 % )
How long would a Li-Ion 7 battery pack=24 volt run that flea amp that states 30 W with 24 V supply ? a week ? A month ? I dunno !
Then the speakers: the higher the efficiency the better> more output given the same power. 4 Ohm speakers offer also higher sensitivity ( but often amplifiers don't like to drive low Z loads ) . I'd like to try this for this kind of application
Dayton Audio PS65LP-4 6-1/2" Ultra Efficient Low Profile Full-Range Driver 4 Ohm
( subwoofer is another matter
)
SO: 24 V 6/10 Ah battery and charger --- 24 V DC supply for home use
30 W per channel, I get lost in those boards.
High eff. speakers
Enclosure must be soundproof and PVC thin pipes I fear are not. Some sandwich or / of other materials might be better.
Some AA batteries won't make anything. If you want power.
I feel that those tiny amps won't make anything too; you know, seeing
the heatsink attached to the transistors and feeling it warm or hot is how some senses ( sight and touch ) feel...the power ! Nowadays class D amplifier have more than 90 % efficiency compared to 40-50 % of class B or AB amplifiers, and the heat is a sign of power transformation ( loss ).
So you still would want big batteries and little power loss ( uhm, ok: speaker's efficiency usually is less than 1 % )
How long would a Li-Ion 7 battery pack=24 volt run that flea amp that states 30 W with 24 V supply ? a week ? A month ? I dunno !
Then the speakers: the higher the efficiency the better> more output given the same power. 4 Ohm speakers offer also higher sensitivity ( but often amplifiers don't like to drive low Z loads ) . I'd like to try this for this kind of application
Dayton Audio PS65LP-4 6-1/2" Ultra Efficient Low Profile Full-Range Driver 4 Ohm
( subwoofer is another matter
)SO: 24 V 6/10 Ah battery and charger --- 24 V DC supply for home use
30 W per channel, I get lost in those boards.
High eff. speakers
Enclosure must be soundproof and PVC thin pipes I fear are not. Some sandwich or / of other materials might be better.
Hmmm ( hi ) let's talk about batteries !!
Some AA batteries won't make anything. If you want power.
I feel that those tiny amps won't make anything too; you know, seeing
the heatsink attached to the transistors and feeling it warm or hot is how some senses ( sight and touch ) feel...the power ! Nowadays class D amplifier have more than 90 % efficiency compared to 40-50 % of class B or AB amplifiers, and the heat is a sign of power transformation ( loss ).
So you still would want big batteries and little power loss ( uhm, ok: speaker's efficiency usually is less than 1 % )
How long would a Li-Ion 7 battery pack=24 volt run that flea amp that states 30 W with 24 V supply ? a week ? A month ? I dunno !
Then the speakers: the higher the efficiency the better> more output given the same power. 4 Ohm speakers offer also higher sensitivity ( but often amplifiers don't like to drive low Z loads ) . I'd like to try this for this kind of application
Dayton Audio PS65LP-4 6-1/2" Ultra Efficient Low Profile Full-Range Driver 4 Ohm
( subwoofer is another matter
SO: 24 V 6/10 Ah battery and charger --- 24 V DC supply for home use
30 W per channel, I get lost in those boards.
High eff. speakers
Enclosure must be soundproof and PVC thin pipes I fear are not. Some sandwich or / of other materials might be better.
I did a research on those tiny amps and seems they DELIVER! Not the highest sound quality but all range and powerful. Also they seem extremely efficient. Multiple people on youtube were amazed by the performance to power ratio.
As for speakers I would love to be able to try the ones you mentioned Pico. I really would. One day perhaps when budget and time allows. For now stuck on w/e i can get for my limited resources.
Also the pipe I plan to use wont be that thin. 8-9 milimeters is substantial structural support for a round object of this size. They are VERY rigid. I plan to experiment with pillow stuffing(polyfill?) and/or line the inside with a soundproofing material(still in research for that)
As for battery life. You are correct. I am now considering dropping this double amplification of the base and going with the lower 30x30 amp.
I now need to find out how to just run the 2 satelite from one channel so both get 15W each and then the wub from the other channel getting 30.
My plan for the enclosure for now is to have the two satelites housed in the smaller diameter of a 90 degree PVC bend whos other end flares to match the diameter of the "T" junction(which houses the woofer). Then capping the satelites into their separate enclosures at the line where the bend begins. Thus making the whole length of the unit - woofer space. As for ported/Passive/sealed my WINISD skills need to improve before being definitive.
I am really bashing my head against the wall with figuring how and at what voltages to power this for maximum efficiency.
Also if any1 knows where HIGH efficiency speakers are used so I can look for second hand(as in cars or w/e) please share info. It is slowly coming together.
Cheers,
Slothor.
I'll try to throw in some tips/opinions, I've built a few boomboxes...
1. Pipe as a material is good, it's quite rigid as it is, just needs some kind of end caps for installing the drivers. If you wan't to minimize the vibrations etc, try to look for self adhesive bitumen sheets etc. The basic stuff is enough, no need to pay extra for the "audio grade" stuff
2. Speakers, do you really need two satellites? If you are facing them in same direction and the signal is mono, you really don't get much more with the second one. And your power consumption rises.
Do those speakers have any kind of crossovers? You probably want a high pass filter for the satellites and a low pass for subwoofer.
If you don't have parameters for those speakers, don't waste your time with WinISD. Just build same volume enclosures as they have now. And without parameters, there's no way to tell what type of enclosure they should have, so again, build a similar type as they have now.
3. Amplifier, you can use the TDA7492. One spec sheet says that with 4 ohm speakers the voltage shouldn't exceed 18 volts, so that's your maximum voltage. You can get quite close with 4 18650 Li-ion batteries. Just add a protection board and get a suitable charger and you should be good to go.
1. Pipe as a material is good, it's quite rigid as it is, just needs some kind of end caps for installing the drivers. If you wan't to minimize the vibrations etc, try to look for self adhesive bitumen sheets etc. The basic stuff is enough, no need to pay extra for the "audio grade" stuff
2. Speakers, do you really need two satellites? If you are facing them in same direction and the signal is mono, you really don't get much more with the second one. And your power consumption rises.
Do those speakers have any kind of crossovers? You probably want a high pass filter for the satellites and a low pass for subwoofer.
If you don't have parameters for those speakers, don't waste your time with WinISD. Just build same volume enclosures as they have now. And without parameters, there's no way to tell what type of enclosure they should have, so again, build a similar type as they have now.
3. Amplifier, you can use the TDA7492. One spec sheet says that with 4 ohm speakers the voltage shouldn't exceed 18 volts, so that's your maximum voltage. You can get quite close with 4 18650 Li-ion batteries. Just add a protection board and get a suitable charger and you should be good to go.
I can see from the questions you are asking you are very new to electronics. I would avoid trying to design your own bass filter or combining stereo signals into mono and then using high level inputs via 1-1 transformers.
Someting like this just needs you to wire the speakers to it and add a power supply. It has built in bluetooth and a built in bass crossover. You have a much better chance of getting it to work well
Just find a couple of full range speakers and a bass driver and you have a much simpler solution. Or if you want to use tweeters as well retain the crossover cap they come with.
TPA3116 100W+2*50W Class D Amplifier Board Bluetooth 2.1 Amplifier Board NewRDFK | eBay
Someting like this just needs you to wire the speakers to it and add a power supply. It has built in bluetooth and a built in bass crossover. You have a much better chance of getting it to work well
Just find a couple of full range speakers and a bass driver and you have a much simpler solution. Or if you want to use tweeters as well retain the crossover cap they come with.
TPA3116 100W+2*50W Class D Amplifier Board Bluetooth 2.1 Amplifier Board NewRDFK | eBay
See
Speaker Project: The Pipe Project
The more bass you want the less portable the unit will become.
Use of passive radiators (al la JBL) should take you lower, but again more weight to carry
Regards,
WHG
Speaker Project: The Pipe Project
The more bass you want the less portable the unit will become.
Use of passive radiators (al la JBL) should take you lower, but again more weight to carry
Regards,
WHG
Some impressive molding skills in that project! I tried to do the same but with not so pretty results, need more practise
I have the same driver, but only using one. And using two 4" passive radiators and those go to pipe's ends. They really don't weigh that much, but there's no specs, so it's a mystery how will it work
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