I'm new to DIY speakers and my questions will probably confirm this. But would appreciate any assistance.
My goal is to build a 2.1 speaker in a single enclosure, but where the woofer and each driver are in their own sealed compartment at the recommended volume for each unit. It would primarily be used for daily music listening via Spotify.
I'm hoping to build my first speaker that has the following components:
The AMP is the TPA3116D2 2.1 and the chip manufacturer states here that the TPA3116D2 model reaches 2 × 50 W Into a 4-Ω BTL Load at 21 V (TPA3116D2). Thats why I'm going for 4 ohm woofer and drivers.
I therefor assume the AMP should be able to power the woofer and drivers (read somewhere that having 50% extra should be a good rule so the AMP is not constantly running on full load).
In regards to a power supply, I was hoping to get a SMPS Dual output power supply. One output for the AMP and the second to power for example a ChromeCast audio and have that "built-in" to the speaker (but the ChromeCast unit on the out side of course for the signal).
Questions I have:
I'm mostly concerned that the power supply in the sealed compartment will not work out due to heat. But would really like to have the power internally. I have not been able to find a suitable external power brick with USB port in order to have just one power unit. Those that I have found are much more expensive than the SMPS options.
My goal is to build a 2.1 speaker in a single enclosure, but where the woofer and each driver are in their own sealed compartment at the recommended volume for each unit. It would primarily be used for daily music listening via Spotify.
I'm hoping to build my first speaker that has the following components:
- Woofer - 1x 50 Watts (4 ohm)
- Drivers (left/rigth) - 2x 30 Watts (4 ohm)
- Amp - 50W (left channel) +50 W (right channel) +100 W (subwoofer)
The AMP is the TPA3116D2 2.1 and the chip manufacturer states here that the TPA3116D2 model reaches 2 × 50 W Into a 4-Ω BTL Load at 21 V (TPA3116D2). Thats why I'm going for 4 ohm woofer and drivers.
I therefor assume the AMP should be able to power the woofer and drivers (read somewhere that having 50% extra should be a good rule so the AMP is not constantly running on full load).
In regards to a power supply, I was hoping to get a SMPS Dual output power supply. One output for the AMP and the second to power for example a ChromeCast audio and have that "built-in" to the speaker (but the ChromeCast unit on the out side of course for the signal).
Questions I have:
- How powerful should the power supply be? The AMP recommends "19-24V / 4-5A" so I assume 120W which is also close to the combined woofer/drivers or 110W. Will that be enough to have a 120W power supply
like for example this one? (CH1:5V 1-6A & CH2:24V 0.4~4A) - In regards to heat dissipation, am I able to place the power supply in a sealed 4 liter enclosure? Current plan is to have the power supply in same sealed compartment as the Woofer which is about 5 liters (4.5 liters if woofer displacement is added and about 4 liters of free volume if all other components are added (amp and power supply)).
- Any other suggestions you might have?
I'm mostly concerned that the power supply in the sealed compartment will not work out due to heat. But would really like to have the power internally. I have not been able to find a suitable external power brick with USB port in order to have just one power unit. Those that I have found are much more expensive than the SMPS options.
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The supply you linked to also has a 5 v 15 A voltage. The supplies I'm famiiliar with are not happy when the 5 v draw is zero.
200 watts of amp means 300 watts or more of heat dissipation. Put a 300 W incandescent bulb in a sealed wood box and measure the temperature after 12 hours. I don't think you will like the answer.
You could put the supply in a sealed corner of the mdf enclosure, with two ports and a fan in front of one of them. This has sonic implications of course; you will have to engineer around the dead space.
People here report they have had good results with connexelectronic.com. I haven't used them and don't know if they have a suitable supply. However 100 W into 4 ohm is +-14 v rail minimum, and if class AB (I don't know the IC) +-28 v rails.
Don't know if chromecast could use +- 15 but most amp supplies supply that also for the op amps.
With my house worth 1000* what I paid for my last amp ($55), I wouldn't be happy with the fan in wooden box arrangement unless I had an overtemperature detector that shut off the power supply. Cheap fans are one of the first things to go out on ATX supplies in PC's. Which BTW you can buy locally, you don't have to have them shipped individually in from overseas.
Have fun.
200 watts of amp means 300 watts or more of heat dissipation. Put a 300 W incandescent bulb in a sealed wood box and measure the temperature after 12 hours. I don't think you will like the answer.
You could put the supply in a sealed corner of the mdf enclosure, with two ports and a fan in front of one of them. This has sonic implications of course; you will have to engineer around the dead space.
People here report they have had good results with connexelectronic.com. I haven't used them and don't know if they have a suitable supply. However 100 W into 4 ohm is +-14 v rail minimum, and if class AB (I don't know the IC) +-28 v rails.
Don't know if chromecast could use +- 15 but most amp supplies supply that also for the op amps.
With my house worth 1000* what I paid for my last amp ($55), I wouldn't be happy with the fan in wooden box arrangement unless I had an overtemperature detector that shut off the power supply. Cheap fans are one of the first things to go out on ATX supplies in PC's. Which BTW you can buy locally, you don't have to have them shipped individually in from overseas.
Have fun.
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Thanks for the reply indianajo.
I wasn't optimistic that the sealed option would work out.
However the amp has a rated power efficiency of ~80% while a incandescent bulb is at ~5% (~95% wasted to heat). So not exactly comparing apples to apples (I think 🙂, but I get you point).
Re-Design option:
I should be able to find a way to place the power supply inside the sealed compartment but having it stick out at the top and have a mesh on top of the speaker (see attached images for an example, where the RED box is the power supply).
What do you think, I assume this should allow for enough heat dissipation?
See attached image of the power supply specifications I was referring to. I'm not good with electrical and power supply, but I thought this one was rated for "CH1:5V 1-6A"?
To simplify, I might just end up with a single power output for the AMP requirements. Having dual was just an idea to have just the one power cable and have the end results nicer. This will also likely allow for a smaller power supply.
If only considering the AMP and Woofer/Drivers, would 100W suffice? For example this one, the MS-100-24 (24V 4.2A).
I wasn't optimistic that the sealed option would work out.
indianajo said:
However the amp has a rated power efficiency of ~80% while a incandescent bulb is at ~5% (~95% wasted to heat). So not exactly comparing apples to apples (I think 🙂, but I get you point).
Re-Design option:
I should be able to find a way to place the power supply inside the sealed compartment but having it stick out at the top and have a mesh on top of the speaker (see attached images for an example, where the RED box is the power supply).
What do you think, I assume this should allow for enough heat dissipation?
indianajo said:
See attached image of the power supply specifications I was referring to. I'm not good with electrical and power supply, but I thought this one was rated for "CH1:5V 1-6A"?
To simplify, I might just end up with a single power output for the AMP requirements. Having dual was just an idea to have just the one power cable and have the end results nicer. This will also likely allow for a smaller power supply.
If only considering the AMP and Woofer/Drivers, would 100W suffice? For example this one, the MS-100-24 (24V 4.2A).
Attachments
You've provided a place for the hot air to get out, but no place for cold air to flow in. Cold air flow up to the PS only if hot air is pulling away from it. Cold air won't flow down if the hot air is pushing up on it. No convection, you need a fan. Or a heat pipe, which is a gadget with solvent in it and a wick to make heat flow through round holes, sideways or down even.
Be aware acoustic suspension requires a sealed box - whether it is the whole box or only part of it. Once you put in holes for the back side of the woofer to pump air on, you need to do bass reflex calculations to determine frequency response (or build it and approve or criticize the sounds). Based on experience, a speaker in a dashboard with about 2 feet path for the backside air to reach you, has a lot better bass than a speaker mounted on a hole in a board standing up in the open air. Even a cardboard box with four closed sides and an open back helps bass.
24 v only supply might work but don't expect 100 W out of it @ 24 v. Maybe 50. Still don't know if your IC is class AB (1/2 rail voltages maximum available) or D (closer to the rail) and I'm not going to read the datasheet for you.
Have fun with Alibaba. I bought a electric bicycle wheel & battery from ***** this summer, since there is no US alternative. The german alternative requires me to pedal, which makes it useless to me for my purpose. Got 11 miles out of the battery, and the 2nd battery drove the wheel 60 miles before the controller quit. The story of that country IMHO, the QA department of the receiving company determines what kind of failure rate & lifespan the product delivers. OTOH the 12v LED strip from ***** worked fine, only one LED burned out in the first day.
Be aware acoustic suspension requires a sealed box - whether it is the whole box or only part of it. Once you put in holes for the back side of the woofer to pump air on, you need to do bass reflex calculations to determine frequency response (or build it and approve or criticize the sounds). Based on experience, a speaker in a dashboard with about 2 feet path for the backside air to reach you, has a lot better bass than a speaker mounted on a hole in a board standing up in the open air. Even a cardboard box with four closed sides and an open back helps bass.
24 v only supply might work but don't expect 100 W out of it @ 24 v. Maybe 50. Still don't know if your IC is class AB (1/2 rail voltages maximum available) or D (closer to the rail) and I'm not going to read the datasheet for you.
Have fun with Alibaba. I bought a electric bicycle wheel & battery from ***** this summer, since there is no US alternative. The german alternative requires me to pedal, which makes it useless to me for my purpose. Got 11 miles out of the battery, and the 2nd battery drove the wheel 60 miles before the controller quit. The story of that country IMHO, the QA department of the receiving company determines what kind of failure rate & lifespan the product delivers. OTOH the 12v LED strip from ***** worked fine, only one LED burned out in the first day.
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Thanks again for the feedback indianajo. Again, I'm just a beginner and appreciate any comments.
The speaker will probably be running at 20-30% most of the times and therefor hoped that top ventilation (heat dissipating freely upwards) would suffice. Considering that many home theater amplifiers around these power specifications only have top ventilation and no fan (but obviously a fan for more powerful systems).
Also considering some fully closed and non-ventilated systems as the Sonso Play:5 that is speculated to be 80 Watt RMS with built in power supply.
Again, I have little knowledge and am just gaining knowlesge and by no meants questioning your feeback that I do appreciate.
Good point regarding the Chine QA... I have done some research for the AMP and this specific board from this seller was tested via oscilloscope and more and had good feedback while others that look the same did not. I will also research the same for the power supply and will purchase from a trusted online merchant (Parts-express or the like). AliExpress was just easy to search but has tons of bad products, but with research there are also quality items there.
However, as having a built-in power supply is increasing the complexity and size of the build, I might possibly end up with an external power adapter similar to this one (but hopefully not from a no-name China brand if I can find one.
The speaker will probably be running at 20-30% most of the times and therefor hoped that top ventilation (heat dissipating freely upwards) would suffice. Considering that many home theater amplifiers around these power specifications only have top ventilation and no fan (but obviously a fan for more powerful systems).
Also considering some fully closed and non-ventilated systems as the Sonso Play:5 that is speculated to be 80 Watt RMS with built in power supply.
Again, I have little knowledge and am just gaining knowlesge and by no meants questioning your feeback that I do appreciate.
Good point regarding the Chine QA... I have done some research for the AMP and this specific board from this seller was tested via oscilloscope and more and had good feedback while others that look the same did not. I will also research the same for the power supply and will purchase from a trusted online merchant (Parts-express or the like). AliExpress was just easy to search but has tons of bad products, but with research there are also quality items there.
However, as having a built-in power supply is increasing the complexity and size of the build, I might possibly end up with an external power adapter similar to this one (but hopefully not from a no-name China brand if I can find one.
I've done pretty well with ****ese goods sold by Farnell, Mouser, Digikey. The four ATX supplies I got from the local computer repair shop lasted less than a year each. The ATX supply I got from mcmelectronics division of farnell is still going at 4 years. I'm still evaluating Parts-express. The "ten inch" woofer I bought has OD of 10" and fits through a 9.5" hole, so I'm having fits making a sealed mount in a speaker box that had a ten inch woofer that fit through a ten inch hole. ^&*(%~!
As I said previously connexelectronic.com has a reputation around here. the smps240 or irs400 IRS400SMPS | Connex Electronic might do you, but check the datasheet that the voltages you want are available as one of the jumpered options. You do have to put those in your own box, provide your own fan, circuit breaker and power cord. Hint- steel boxes grounded to the 3rd pin of the power cord howl less at switching frequency into sensitive analog audio inputs. Also chokes in the box may keep RF off the DC feed wires coming out. I have plenty of chokes from all those dead ATX supplies.
However there are things on ebay & amazon maybe worth the risk. Not semiconductors, reported nearly 100% counterfeit, but these LED strips I bought were 1/20 the price of undercounter lights in a home improvement store. Looks good in an organ music rack instead of the hot old flourescent bulb. Plus the LED lights I got from ****-**** burned out in two years, so no great bargains there either.
As I said previously connexelectronic.com has a reputation around here. the smps240 or irs400 IRS400SMPS | Connex Electronic might do you, but check the datasheet that the voltages you want are available as one of the jumpered options. You do have to put those in your own box, provide your own fan, circuit breaker and power cord. Hint- steel boxes grounded to the 3rd pin of the power cord howl less at switching frequency into sensitive analog audio inputs. Also chokes in the box may keep RF off the DC feed wires coming out. I have plenty of chokes from all those dead ATX supplies.
However there are things on ebay & amazon maybe worth the risk. Not semiconductors, reported nearly 100% counterfeit, but these LED strips I bought were 1/20 the price of undercounter lights in a home improvement store. Looks good in an organ music rack instead of the hot old flourescent bulb. Plus the LED lights I got from ****-**** burned out in two years, so no great bargains there either.
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