I went back and read several posts over again, and it is clear that the center brace does not function as a wall. I'm guessing that the center brace is off-center, as saturnus states that the backs of the speakers touch each other, and that glue connects one side of the two speakers to the center brace.
Last night I wired the speakers up to the amp (6B) and battery, and listened a little. It sounds decent, though obviously has no bass (no enclosure yet). I'm going to home depot tomorrow to get the wood and tools I'll need. If anyone has any tips or ideas, feel free to share them
Last night I wired the speakers up to the amp (6B) and battery, and listened a little. It sounds decent, though obviously has no bass (no enclosure yet). I'm going to home depot tomorrow to get the wood and tools I'll need. If anyone has any tips or ideas, feel free to share them
Hey aphelion,
Sorry for slow reply mate, correct the centre brace does not divide the 2 woofers. But it is central, one of the circular holes in the brace fits the woofer magnets tightly. Look back to post 206 and download the Google sketch up file (and download goggle sketch up if you don’t have it. You may as well get the timed “pro” version and just revert back to the free one when the trial expires. I also have the cut sheets that I drew up in AutoCAD. No guarantees on them though mate, they were covered in pen and notes by the time I finished building.
Cheers,
Tim
Sorry for slow reply mate, correct the centre brace does not divide the 2 woofers. But it is central, one of the circular holes in the brace fits the woofer magnets tightly. Look back to post 206 and download the Google sketch up file (and download goggle sketch up if you don’t have it. You may as well get the timed “pro” version and just revert back to the free one when the trial expires. I also have the cut sheets that I drew up in AutoCAD. No guarantees on them though mate, they were covered in pen and notes by the time I finished building.
Cheers,
Tim
Tim,
The cad drawing linked in post 206 is unavailable, unfortunately :/ A few posts ago, Saturnus said that he wouldn't be able to get the cad drawing back up until he was able to get back into work.
Thanks for letting me know about the center brace though, that helps. I'm actually almost done with the box now - and it looks like I'll have it done in time for that trip I'm taking on Saturday!
However, there is still one issue that I'm having trouble with. I still don't know how to wire that NTE-4 transformer in. Saturnus, could you please give me an idea of how this is done?
Thanks to everyone for all the help so far. I'll post pics of the build soon!
The cad drawing linked in post 206 is unavailable, unfortunately :/ A few posts ago, Saturnus said that he wouldn't be able to get the cad drawing back up until he was able to get back into work.
Thanks for letting me know about the center brace though, that helps. I'm actually almost done with the box now - and it looks like I'll have it done in time for that trip I'm taking on Saturday!
However, there is still one issue that I'm having trouble with. I still don't know how to wire that NTE-4 transformer in. Saturnus, could you please give me an idea of how this is done?
Thanks to everyone for all the help so far. I'll post pics of the build soon!
Micro Boominator
I'm working on a "Micro Boominator." This unit will be mounted on a rear rack of a bicycle. It runs off of a T-Amp and weighs, I'm guessing here as it's not done, less than 5 Kilos (11 lbs.). We tested the sound tonight and it's certainly not bass heavy, but sounds pretty good. Speakers face right and left, but the right side of the speaker cabinet can flip up via a 180 degree hinge, and face the same way as the left speakers if you want the sound in one direction. It also has a built in Rolls MX22 mixer so you can use a microphone and speak, with or without music in the background. Here is the photo set:
http://www.flickr.com/photos/macpaulster/sets/72157615708283202/
The project isn't done yet and I haven't captioned the photos yet, but both will be done soon. Comments, questions, suggestions, criticisms, applause all appreciated!
I'm working on a "Micro Boominator." This unit will be mounted on a rear rack of a bicycle. It runs off of a T-Amp and weighs, I'm guessing here as it's not done, less than 5 Kilos (11 lbs.). We tested the sound tonight and it's certainly not bass heavy, but sounds pretty good. Speakers face right and left, but the right side of the speaker cabinet can flip up via a 180 degree hinge, and face the same way as the left speakers if you want the sound in one direction. It also has a built in Rolls MX22 mixer so you can use a microphone and speak, with or without music in the background. Here is the photo set:
http://www.flickr.com/photos/macpaulster/sets/72157615708283202/
The project isn't done yet and I haven't captioned the photos yet, but both will be done soon. Comments, questions, suggestions, criticisms, applause all appreciated!
Bike Speak Micro System
Thanks Buckapound. Good point. It would be great to be able to share the ability to hear our systems in a good way. So far we've just briefly tested the audio in one channel. It sounds great but as you might expect is a little lacking in bass with the small speakers. With the line out from the MX22 mixer board you certainly could add compact powered sub. But the verdict isn't in yet as we need to get the whole thing sealed up and running. Today we plan to finish the custom board we made to limit the current from the pedal power charging system we are building. I've got a few new photos showing how it fits in the bike and the generator mount at the end of this photo set:
www.flickr.com/photos/macpaulster/sets/72157615708283202/
Buckapound said:
Thanks Buckapound. Good point. It would be great to be able to share the ability to hear our systems in a good way. So far we've just briefly tested the audio in one channel. It sounds great but as you might expect is a little lacking in bass with the small speakers. With the line out from the MX22 mixer board you certainly could add compact powered sub. But the verdict isn't in yet as we need to get the whole thing sealed up and running. Today we plan to finish the custom board we made to limit the current from the pedal power charging system we are building. I've got a few new photos showing how it fits in the bike and the generator mount at the end of this photo set:
www.flickr.com/photos/macpaulster/sets/72157615708283202/
Hi everyone and especially Saturnus,
We met at Roskilde '07 and I've been wanting to make a boominator ever since. I was the guy in the mud colored clothes. I made the system in the picture here http://farm4.static.flickr.com/3187/2482117062_53c63872cf.jpg?v=0 from some flea market parts. I called it the Port-A-Party and it was portable when I was in university and my building had elevators and tile floors for the wheels to roll on. Now I live up 3 flights of stairs and want to make a slightly smaller scale boominator.
I'm new to custom audio projects and was wondering about calculating enclosure size. When you do the magnet to magnet construction, do you still only need the enclosure volume for one speaker or do you have to double it or do some other math?
I was looking at Pyle PPA8 8" woofers instead of 10" inch speakers so I could shrink the volume a little bit. I realize at 89.2dB, they're not as sensitive as what you suggest, but they are only $17 from mcmelectronics.com when you buy 4. The specs are here http://www.pyleaudio.com/manuals/PPA8-10-12-15-18.pdf on page 5. The mounting depth is 3.41" so the magnet to magnet depth would be about 17.3cm. Is it more complicated than using the 0.696 cubic ft (19.7l) volume in the spec and choosing enclosure dimensions to match it. My numbers suggest a 18cm x 25cm x 38cm enclosure for each side would meet this with room to put tweeters above the woofers and I'd just need to add some size overall size for bracing.
Sorry for the long intro post and I'm sure I'll have more questions, but I just wanted to know how to chose my enclosure size. I know porting (I like your handle ports) affects behavior too, but I'm not sure how.
Thanks,
Aron
We met at Roskilde '07 and I've been wanting to make a boominator ever since. I was the guy in the mud colored clothes
. I made the system in the picture here http://farm4.static.flickr.com/3187/2482117062_53c63872cf.jpg?v=0 from some flea market parts. I called it the Port-A-Party and it was portable when I was in university and my building had elevators and tile floors for the wheels to roll on. Now I live up 3 flights of stairs and want to make a slightly smaller scale boominator.I'm new to custom audio projects and was wondering about calculating enclosure size. When you do the magnet to magnet construction, do you still only need the enclosure volume for one speaker or do you have to double it or do some other math?
I was looking at Pyle PPA8 8" woofers instead of 10" inch speakers so I could shrink the volume a little bit. I realize at 89.2dB, they're not as sensitive as what you suggest, but they are only $17 from mcmelectronics.com when you buy 4. The specs are here http://www.pyleaudio.com/manuals/PPA8-10-12-15-18.pdf on page 5. The mounting depth is 3.41" so the magnet to magnet depth would be about 17.3cm. Is it more complicated than using the 0.696 cubic ft (19.7l) volume in the spec and choosing enclosure dimensions to match it. My numbers suggest a 18cm x 25cm x 38cm enclosure for each side would meet this with room to put tweeters above the woofers and I'd just need to add some size overall size for bracing.
Sorry for the long intro post and I'm sure I'll have more questions, but I just wanted to know how to chose my enclosure size. I know porting (I like your handle ports) affects behavior too, but I'm not sure how.
Thanks,
Aron
Hi Zota,
I would say nothing really changes other than to double the enclosure volume for two drivers from what you calculated for one. I have downloaded some interesting freeware to simulate the roll-off curve for an enclosure for a given speaker.
http://www.ajdesigner.com/speaker/index.php
Vented enclosures are roughly twice the size of a closed enclosure for a given driver.
I would say nothing really changes other than to double the enclosure volume for two drivers from what you calculated for one. I have downloaded some interesting freeware to simulate the roll-off curve for an enclosure for a given speaker.
http://www.ajdesigner.com/speaker/index.php
Vented enclosures are roughly twice the size of a closed enclosure for a given driver.
v-bro,
Thank you for the link. It seems very useful. I poked around at the calculator and if having the two speakers mounted magnet to magnet requires me to double the size for the enclose, then I am getting prohibitively large enclosure sizes for a portable system. The volumes are coming in much larger than what Saturnus built, so I'm somewhat confused. Also, the sealed volume calculator requires you to input Qtc. I'm not finding that parameter listed in the specifications I've looked at. The calculator is very sensity to that value, so I can't really use it unless I can find that number. I'm thinking I might be in a bit over my head trying to design an enclosure for my first audio project.
Aron
Thank you for the link. It seems very useful. I poked around at the calculator and if having the two speakers mounted magnet to magnet requires me to double the size for the enclose, then I am getting prohibitively large enclosure sizes for a portable system. The volumes are coming in much larger than what Saturnus built, so I'm somewhat confused. Also, the sealed volume calculator requires you to input Qtc. I'm not finding that parameter listed in the specifications I've looked at. The calculator is very sensity to that value, so I can't really use it unless I can find that number. I'm thinking I might be in a bit over my head trying to design an enclosure for my first audio project.
Aron
I'm not doing well at reading or typing. Here is what the AJ Designer site actually says, "Qtc: choose a value between 0.1 and 1.5. A value between 0.5 and 1.2 should give good results."
So, v-bro, your 0.7 number is right on target. Thank you for your patience with a novice. It looks like a sealed system is much closer to the size I was hoping for, (though from what I'm reading, a ported system can potentially put out 3-6dB more at the low end). One of the factors driving my trade-offs is that the system fit in the somewhat small opening for the trunk of my car.
Another novice question here, what happens if I make an enclosure that is too small? Do I just loose bass response or can it actually damage the components?
Aron
So, v-bro, your 0.7 number is right on target. Thank you for your patience with a novice. It looks like a sealed system is much closer to the size I was hoping for, (though from what I'm reading, a ported system can potentially put out 3-6dB more at the low end). One of the factors driving my trade-offs is that the system fit in the somewhat small opening for the trunk of my car.
Another novice question here, what happens if I make an enclosure that is too small? Do I just loose bass response or can it actually damage the components?
Aron
No worries, you won't damage anything. The only thing that really happens is that your bass will start to roll off at a higher point. It won't change the actual output.
You could stick together a test enclosure of some cheap material to try it out first.
A bass reflex cab indeed gives more bass output, but also less precise. You could get away with a smaller bass reflex enclosure and tune the port to compensate a little for it. Generally larger and smaller ports give out more higher frequency smaller and longer ports give out more low frequency at the cost of some efficiency... Of course you're drifting from the ideal situation a bit here. But hey, you have to sacrifice something for the smaller size... This is often done by commercial designs as well...
You could stick together a test enclosure of some cheap material to try it out first.
A bass reflex cab indeed gives more bass output, but also less precise. You could get away with a smaller bass reflex enclosure and tune the port to compensate a little for it. Generally larger and smaller ports give out more higher frequency smaller and longer ports give out more low frequency at the cost of some efficiency... Of course you're drifting from the ideal situation a bit here. But hey, you have to sacrifice something for the smaller size... This is often done by commercial designs as well...
I've started ordering my components. I've got the amp6 basic, solar panels from siliconsolar, a solar charge controller, and a battery all on the way. Now I'm torn between two choices for speakers.
One is a $40 woofer with carbon fiber surround with 92dB(W/m) SPL.
http://www.mcmelectronics.com/product.aspx?productid=55-3550
I used the ajdesigner calculator (using QB3 alignment. I'm not quite sure what that means) and a few others I found online and they all suggest a 15 liter enclosure would be good based on the parameters listed. Even with bracing, volume of the speaker cones, etc, I can make an enclosure very close to the size I wanted without really sacrificing sound quality. F3 for that system is 87-90Hz depending on the calculator used. Once I add tweeters and crossover components, that route would run into about $180-200 for the audio components.
My other choice is a ceiling speaker from Parts Express at only $12 per woofer.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-007
They have 2 cones in the speaker to cover highs and lows so I won't need any crossover, but they don't list the full specifications. The tech support guy on the phone at parts express says he's used/tested them and they are 94dB(W/m) SPL. He thought they would be really good for a solar boombox, where sound quality isn't going to be the most important. It takes away the challenge of making my own crossovers, but also saves me complexity and about $120. I'm a little worried about the 20A RMS rating with the amp6. I also think I'll lose some audio quality. The frequency response range for those is 100Hz-20,000kHz (as opposed to 30Hz-8kHz for the others).
Any thoughts and feedback would be really appreciated.
Aron
One is a $40 woofer with carbon fiber surround with 92dB(W/m) SPL.
http://www.mcmelectronics.com/product.aspx?productid=55-3550
I used the ajdesigner calculator (using QB3 alignment. I'm not quite sure what that means) and a few others I found online and they all suggest a 15 liter enclosure would be good based on the parameters listed. Even with bracing, volume of the speaker cones, etc, I can make an enclosure very close to the size I wanted without really sacrificing sound quality. F3 for that system is 87-90Hz depending on the calculator used. Once I add tweeters and crossover components, that route would run into about $180-200 for the audio components.
My other choice is a ceiling speaker from Parts Express at only $12 per woofer.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-007
They have 2 cones in the speaker to cover highs and lows so I won't need any crossover, but they don't list the full specifications. The tech support guy on the phone at parts express says he's used/tested them and they are 94dB(W/m) SPL. He thought they would be really good for a solar boombox, where sound quality isn't going to be the most important. It takes away the challenge of making my own crossovers, but also saves me complexity and about $120. I'm a little worried about the 20A RMS rating with the amp6. I also think I'll lose some audio quality. The frequency response range for those is 100Hz-20,000kHz (as opposed to 30Hz-8kHz for the others).
Any thoughts and feedback would be really appreciated.
Aron
For this type of project people normally go for the max sensitivity to get the most output from the minimum power.
On this basis something like this would be more appropriate.
http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-1735-/55-1735
or you could look for a guitar amp speaker which is also likely to be very high sensitivity.
Regards,
Andrew
On this basis something like this would be more appropriate.
http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-1735-/55-1735
or you could look for a guitar amp speaker which is also likely to be very high sensitivity.
Regards,
Andrew