Hi. I'm looking for help with designing an ultra lightweight speaker system for music performances. It needs to be small and light enough to carry by hand over long distances and to transport on buses and trains. Yet it needs to be loud enough to fill a hall with 100 people. There may be lots of different venues and mains power is always available. The music will be folk and MOR, so not much need for heavy bass. There will also be vocals from a mic which need to be heard with good clarity. I know, it sound impossible.
My thinking so far. Weight is the killer and I have to save every gram I can. Loudspeakers are heavy, so the fewer of them the better. Ideally I'd prefer a single full range driver for the whole system, say 8 or 10 inch. And it needs to have high efficiency so the amp can be smaller and lighter. Obviously the amp should be class D with a small switched mode power supply.
The cabinet needs to be small and light, both of which are enemies of good sound quality. It may be OK if bass response is lacking, provided people can hear the music and vocals. I'm thinking of using quite thin plywood, say 6 or 8mm with lots of internal bracing to stiffen it. The overall shape would be trapezoidal to minimise resonance. I'm not sure what internal volume to use. Ideally, not much more than the speaker itself.
I've not much experience with speaker design. The last cabinets I made were in 1970 from a Wharfedale Unit 3 kit. I'd welcome suggestions on the best way to proceed and recommendations for drivers and amps.
My thinking so far. Weight is the killer and I have to save every gram I can. Loudspeakers are heavy, so the fewer of them the better. Ideally I'd prefer a single full range driver for the whole system, say 8 or 10 inch. And it needs to have high efficiency so the amp can be smaller and lighter. Obviously the amp should be class D with a small switched mode power supply.
The cabinet needs to be small and light, both of which are enemies of good sound quality. It may be OK if bass response is lacking, provided people can hear the music and vocals. I'm thinking of using quite thin plywood, say 6 or 8mm with lots of internal bracing to stiffen it. The overall shape would be trapezoidal to minimise resonance. I'm not sure what internal volume to use. Ideally, not much more than the speaker itself.
I've not much experience with speaker design. The last cabinets I made were in 1970 from a Wharfedale Unit 3 kit. I'd welcome suggestions on the best way to proceed and recommendations for drivers and amps.
What comes to my mind are modern coaxial PA drivers with shared neodymium magnet for LF and HF units. They should be fairly light and they can take more power than fullrange drivers.
Regarding cabinet, Karlson K12 resized for 10in driver, or Karlson XKi also for 10in format are worth investigating. There are several threads on diyaudio you can find with search feature.
Regarding cabinet, Karlson K12 resized for 10in driver, or Karlson XKi also for 10in format are worth investigating. There are several threads on diyaudio you can find with search feature.
My primary questions:
How small?
How light?
How much SPL?
What frequency range?
Are you worried about directivity?
And finally, if you're not just building it because you want to, what aspects are you looking for that are not available commercially? Small, high power PA speakers are more common now, and they can be cheaper than rolling your own. Durability issues have typically been solved as well.
How small?
How light?
How much SPL?
What frequency range?
Are you worried about directivity?
And finally, if you're not just building it because you want to, what aspects are you looking for that are not available commercially? Small, high power PA speakers are more common now, and they can be cheaper than rolling your own. Durability issues have typically been solved as well.
With live sound drivers.
For better efficiency your looking at larger diameter speakers.
If you want full range / dual cone drivers assume 10" or 12" for best efficiency
Typical 10" is looking for 25 to 35 liters of volume
Typical 12" is looking for 42 to 62 liters of volume
Reflex/ported cabinet rather small or larger wont follow typical alignments.
basically tune to Fs of the speaker or about 3 to 5 Hz above the drivers Fs
For better bass you would shoot for the larger.
for smaller size, with trade off of less bass.
Speaker model software would show you realistic power handling.
With typical models with 2 to 4mm Xmax for 10% distortion
250 watt thermal rated speakers would be around 60 to 70 watts.
Your single driver solution might be Max SPL around 115 to 118 dB
The system is about the same as usual smaller portable PA system cab/head combos
with single 10" or 12" drivers. 2x speakers and a 200/250 watt amplifier / mixer
For lightweight your approach is correct, most weight is the actual enclosure wood.
I would keep the front baffle thicker, but use well braced thinner sides.
Some have used sign plastic, then wrap with fiberglass.
As you have noticed there is many commercial 1x10 or 1x12 Pa cabinets already
using fiberglass/plastic composite enclosures. Often lighter or same as Ultra lite
Diy. The lift weight can only be improved so much, main advantage is Wheels.
or built in dolly system like a suitcase so the device is rolled not carried.
But will always need to be lifted at some point, but rolled over a distance
For better efficiency your looking at larger diameter speakers.
If you want full range / dual cone drivers assume 10" or 12" for best efficiency
Typical 10" is looking for 25 to 35 liters of volume
Typical 12" is looking for 42 to 62 liters of volume
Reflex/ported cabinet rather small or larger wont follow typical alignments.
basically tune to Fs of the speaker or about 3 to 5 Hz above the drivers Fs
For better bass you would shoot for the larger.
for smaller size, with trade off of less bass.
Speaker model software would show you realistic power handling.
With typical models with 2 to 4mm Xmax for 10% distortion
250 watt thermal rated speakers would be around 60 to 70 watts.
Your single driver solution might be Max SPL around 115 to 118 dB
The system is about the same as usual smaller portable PA system cab/head combos
with single 10" or 12" drivers. 2x speakers and a 200/250 watt amplifier / mixer
For lightweight your approach is correct, most weight is the actual enclosure wood.
I would keep the front baffle thicker, but use well braced thinner sides.
Some have used sign plastic, then wrap with fiberglass.
As you have noticed there is many commercial 1x10 or 1x12 Pa cabinets already
using fiberglass/plastic composite enclosures. Often lighter or same as Ultra lite
Diy. The lift weight can only be improved so much, main advantage is Wheels.
or built in dolly system like a suitcase so the device is rolled not carried.
But will always need to be lifted at some point, but rolled over a distance
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Get a pair of B&C 10CL’s with Neodymium motor. Design an XPS foam slot loaded bandpass sub around it. For PA you need to reach 60Hz is low enough. Run it up to 250Hz for the crossover. It will be 4ohms and 96+6dB sensitive at 2.83v. About -6dB baffle step loss and so 96dB total sensitivity. Instead of a bandpass box, A regular prismatic box with the woofers opposed on front and back as a bipole would provide force cancellation and reduce distortion of the one in back has magnet facing out. This would reduce baffle step losses too and sensitivity would go up.
Here is how I made subs with XPS foam.
https://www.diyaudio.com/community/threads/light-as-air-slot-loaded-band-pass-sub.258433/
For the top, a sealed XPS foam box (braced and stuffed with fiberglass) PRV5MR450NDY high passed at 250Hz. It has enough top end to not need a tweeter. If you really wanted a tweeter add a planar GRS (with sealed back). You could have a circa 94dB at 2.83v system capable of enough SPL for a 100 group party.
Assuming a party of 100 people is about 30ft W x 50ft deep. And we want 90dB at the middle of the dance floor 25ft away. That’s about 8m at the middle. 8m is 3 doublings 3x3dB) or 90+9dB at 1m.
A 94dB at 2.83v (4ohms) system will make 99dB about 4-5W. With a portable 50W a Class D amp that leaves you plenty of headroom.
Here is how I made subs with XPS foam.
https://www.diyaudio.com/community/threads/light-as-air-slot-loaded-band-pass-sub.258433/
For the top, a sealed XPS foam box (braced and stuffed with fiberglass) PRV5MR450NDY high passed at 250Hz. It has enough top end to not need a tweeter. If you really wanted a tweeter add a planar GRS (with sealed back). You could have a circa 94dB at 2.83v system capable of enough SPL for a 100 group party.
Assuming a party of 100 people is about 30ft W x 50ft deep. And we want 90dB at the middle of the dance floor 25ft away. That’s about 8m at the middle. 8m is 3 doublings 3x3dB) or 90+9dB at 1m.
A 94dB at 2.83v (4ohms) system will make 99dB about 4-5W. With a portable 50W a Class D amp that leaves you plenty of headroom.
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Thanks for these really well thought out suggestions. I'm grateful for all your help and I'm studying the details you supplied.
@xrk971. I'm loving the idea of making the boxes from XPS foam. Who knew this was possible. This will be much lighter than the plywood I had in mind and probably easier to construct with less bracing. I like the drivers you recommend. Surprisingly, the weight of these four drivers seems comparable with the weight of a single full range coaxial driver (4 times 1.2 kg versus 4.7kg). But I didn't quite follow how to mount the pair back to back.
@WhiteDragon. Thanks for your comment that I can get better efficiency with bigger diameter drivers. I've also been looking at the 12 inch Fane 12-250TC, which has a remarksble sensitivity of 100dB. I wonder if this will help in this project. Or if I can find a smaller diameter speaker with a similar efficiency.
It would be nice if there was an off-the-shelf product that met my needs. But typical party systems are not designed for ultra light weight. In fact, they are often big and heavy. The Soundboks weighs 15.4kg and is not going anywhere. The slightly more portable Soundboks Go is still 9.2kg, way too heavy for me. The review at L&B comments unfavourably on the weight and the sound quality. The JBL EON ONE Compact is a bit heavier still at 10.6kg. I'm using mains power, so don't need the internal batteries which add unneccessary weight to all these systems. And they are all very expensive. You only become aware of the weight of something when you have to lug it around for long distances. It's quite different from throwing something in the back of a car and walking into the venue with it.
I'm getting near the point where I can order some new hardware and start experimenting. Thanks.
@xrk971. I'm loving the idea of making the boxes from XPS foam. Who knew this was possible. This will be much lighter than the plywood I had in mind and probably easier to construct with less bracing. I like the drivers you recommend. Surprisingly, the weight of these four drivers seems comparable with the weight of a single full range coaxial driver (4 times 1.2 kg versus 4.7kg). But I didn't quite follow how to mount the pair back to back.
@WhiteDragon. Thanks for your comment that I can get better efficiency with bigger diameter drivers. I've also been looking at the 12 inch Fane 12-250TC, which has a remarksble sensitivity of 100dB. I wonder if this will help in this project. Or if I can find a smaller diameter speaker with a similar efficiency.
It would be nice if there was an off-the-shelf product that met my needs. But typical party systems are not designed for ultra light weight. In fact, they are often big and heavy. The Soundboks weighs 15.4kg and is not going anywhere. The slightly more portable Soundboks Go is still 9.2kg, way too heavy for me. The review at L&B comments unfavourably on the weight and the sound quality. The JBL EON ONE Compact is a bit heavier still at 10.6kg. I'm using mains power, so don't need the internal batteries which add unneccessary weight to all these systems. And they are all very expensive. You only become aware of the weight of something when you have to lug it around for long distances. It's quite different from throwing something in the back of a car and walking into the venue with it.
I'm getting near the point where I can order some new hardware and start experimenting. Thanks.
I know this is DIYaudio, but, in case you were wondering, the speaker you are looking for already exists.
It's the Bose L1.
I've seen/heard it in action, and there's nothing out there like it. Compact, lightweight enough, and great sound.
It's the best PA system for small bands. Period.
Even trying to DIY it, you will need to spend much on drivers, materials, DSP amps, etc...
It's the Bose L1.
I've seen/heard it in action, and there's nothing out there like it. Compact, lightweight enough, and great sound.
It's the best PA system for small bands. Period.
Even trying to DIY it, you will need to spend much on drivers, materials, DSP amps, etc...
Thanks @perceval. The Bose L1 is a nice speaker but it's big, expensive and extremely heavy. The only way to make it portable is to leave the sub at home and just take the column part to the gig. This doesn't seem to be a valid configuration according to Bose, as there's no LF driver. Bose offer various configurations that include a sub. For the set up I looked at, the sub measures 418 x 339 x 426 mm, to which you have to add the line array parts. The whole thing weighs 13.8kg. I don't think I'd get very far carrying that by hand. Can you clarify which configuration you say is "lightweight enough"?
There are configurations, and I believe a choice of subs?
The setup I heard was the smallest one, and she used a bag to carry it all. I think it was a backpack style bag.
Yes, it had a bit of weight, but compared to traditional PA/monitors, it was quite small and light.
Using thin ply and "a lot of" bracing, will get you a heavy box as well, plus all the space between the bracing will vibrate anyway. Will give you a lot of distortion.
Using XPS boards will make it lighter, but I wonder how it will survive more than a few trips before the corners come ungluing.
The beauty of the Bose line array is that the sound will project much better than any coaxial could.
It also comes with inputs and a mixer.
It is made solid and will take the abuse.
I'm afraid if you try to save money by making a light version, you'll end up spending more money in the end trying to fix it over and over.
Been there, done that! 🙂
Here's a set that is factory refurbished. Cheaper.
https://www.proaudiostar.com/bose-l...2gEiCv50BsrYwQaGRZE-CpG7MaEbYr-xoCHkEQAvD_BwE
The setup I heard was the smallest one, and she used a bag to carry it all. I think it was a backpack style bag.
Yes, it had a bit of weight, but compared to traditional PA/monitors, it was quite small and light.
Using thin ply and "a lot of" bracing, will get you a heavy box as well, plus all the space between the bracing will vibrate anyway. Will give you a lot of distortion.
Using XPS boards will make it lighter, but I wonder how it will survive more than a few trips before the corners come ungluing.
The beauty of the Bose line array is that the sound will project much better than any coaxial could.
It also comes with inputs and a mixer.
It is made solid and will take the abuse.
I'm afraid if you try to save money by making a light version, you'll end up spending more money in the end trying to fix it over and over.
Been there, done that! 🙂
Here's a set that is factory refurbished. Cheaper.
https://www.proaudiostar.com/bose-l...2gEiCv50BsrYwQaGRZE-CpG7MaEbYr-xoCHkEQAvD_BwE
Some experience for you......
We live in NYC and work within the performance and recording world. So very many performers do exactly what you intend so focus on form factor first..........it doesn’t have to be very light or very small......it just needs to easy to transport.......put wheels and a handle on it!.....this is a fast growing segment within pro electronics.....take a look at the commercial offerings for inspritation.
We live in NYC and work within the performance and recording world. So very many performers do exactly what you intend so focus on form factor first..........it doesn’t have to be very light or very small......it just needs to easy to transport.......put wheels and a handle on it!.....this is a fast growing segment within pro electronics.....take a look at the commercial offerings for inspritation.
^^^
Totally. I wrote a thread somewhere about designing a standard suitcase size speaker; complete with handles and wheels. I can’t recall where that thread is. Anyway: it’s doable. Totally doable.
Set the limits at standard industry size large suitcase (62” total dimensions) and weight (40lbs) complete with handle, wheel, and built in li-po battery.
Can’t believe it hasn’t been done already.
I like to buy off the rack too due to limited time for R&D, but sometimes you do have DIY…
Totally. I wrote a thread somewhere about designing a standard suitcase size speaker; complete with handles and wheels. I can’t recall where that thread is. Anyway: it’s doable. Totally doable.
Set the limits at standard industry size large suitcase (62” total dimensions) and weight (40lbs) complete with handle, wheel, and built in li-po battery.
Can’t believe it hasn’t been done already.
I like to buy off the rack too due to limited time for R&D, but sometimes you do have DIY…
