whelibob said:
Piezo need at least 24 hour, and even better 100 hours, before their sound settles in so they've probably gotten a lot better.
Anyways, I always dampen the plastic housing with blue tac, so I don't experience any problems. I also screw the piezo element of the horn, and glue it back on.
Yeah i tried also to dampen the piezo with blue tac but didn't help.Saturnus said:
Is there any other good piezos then motorolas original piezos and zomax hp100? since zomax hp100 piezos would cost me 468 DKK(62euros) due shipping costs and its a bit too much for two piezos. Maybe ill send you money saturnus and you send them to me with cheaper shipping costs
What would be a good value for a resistor for this piezo:
http://www.adelcom.net/MOTOROLA_ksn1005b.htm
3.5khz would be the crossover frequency.
Supposed to be a good piezo, just ordered two of them.
Tried to count piezo value myself, but i came out with crazy numbers.
Thanks alot in advance!
http://www.adelcom.net/MOTOROLA_ksn1005b.htm
3.5khz would be the crossover frequency.
Supposed to be a good piezo, just ordered two of them.
Tried to count piezo value myself, but i came out with crazy numbers.
Thanks alot in advance!
Wow guys! You have done totally amazing and boomblasting audio systems! Cheers for that. I'm also considering what kind of boomblaster I'm going to do. The Boominator is awesome but it's propably a little bit too much for me.
Is there any sense to use car speakers for this project? I'm thinking about Blaupunkt GTx 803 -speakers but I can't find any Thiele/Small parameters for these. What kind of enclosure is suitable for these speakers is total mystery for me... Anyhow using these speakers it would be pretty easy to make my own version of DIY blaster.
Do you second this idea or should I consider again?
Is there any sense to use car speakers for this project? I'm thinking about Blaupunkt GTx 803 -speakers but I can't find any Thiele/Small parameters for these. What kind of enclosure is suitable for these speakers is total mystery for me... Anyhow using these speakers it would be pretty easy to make my own version of DIY blaster.
Do you second this idea or should I consider again?
Der Alte said:
Thanks
Depends. It won't play very loud with those. 89 dB/W/m in 4 Ohms is very very low. You need a hundred or several hundred watt amp to make it play as loud as the Boominator and that would require a battery pack the size of a car.
However, it might be loud enough for your purposes.
Oh, I didn't notice that sensitivity is so low in these Blaupunkt's. More suitable and propably better option will be either DLS Coaxial Series 428 or DLS Performance series 126. But again, I can't find any info what kind of enclosure is suitable for these speakers, douh!!!
What I'm looking for is an allrounder boombox that beats for example the JVC's boomblaster. After all it is possible that the boominator is the one and only -concept that I'm going to build eventhough it is a little bit to extreme for me.
What I'm looking for is an allrounder boombox that beats for example the JVC's boomblaster. After all it is possible that the boominator is the one and only -concept that I'm going to build eventhough it is a little bit to extreme for me.
Der Alte,
Just as a point of reference, I have a much smaller boombox than the Boominator, and have tried the following drivers in it:
- Alpair CHR70 (85 dB)
- Tang Band W4-1320 SD (89 dB)
- CSS FR125 (85.5 dB)
Even though they may not be particularly efficient, I find all of these, give more than an adequate amount of sound when powered by an amp6. However, I am not dragging the thing to rock festivals, so you definitely have to consider how you plan to use it.
I currently have the Alpairs in place, as they sounded about as good as the CSS, but are 4 ohms rather than 8 and their metal cone and dust cap construction makes them more resistant to dust and rain. They're considerably cheaper, too. I found the Tang Bands a bit shrill/harsh
I think you will generally find that smaller drivers are less efficient, so if you're planning a smaller box, you may not be able to get super high efficiency.
--Buckapound
Just as a point of reference, I have a much smaller boombox than the Boominator, and have tried the following drivers in it:
- Alpair CHR70 (85 dB)
- Tang Band W4-1320 SD (89 dB)
- CSS FR125 (85.5 dB)
Even though they may not be particularly efficient, I find all of these, give more than an adequate amount of sound when powered by an amp6. However, I am not dragging the thing to rock festivals, so you definitely have to consider how you plan to use it.
I currently have the Alpairs in place, as they sounded about as good as the CSS, but are 4 ohms rather than 8 and their metal cone and dust cap construction makes them more resistant to dust and rain. They're considerably cheaper, too. I found the Tang Bands a bit shrill/harsh
I think you will generally find that smaller drivers are less efficient, so if you're planning a smaller box, you may not be able to get super high efficiency.
--Buckapound
"you divide the Vb by Pi (3.14), and multiply Fb with Square root of 2 (1.414) to get optimum Qb for outdoors purposes 1.212."
I am planning on building my own boombox to have a mobile skate soundsystem but a bit lost by the above... Could some one please give me a dummies guide to working this out...
Here is my shot in the dark so far:
Vb= Enclosure volume
Fb= The frequency of the enclosure
Now this is where I get lost, do just let WinISD do the first calculation and then tweak the numbers in the box volume and tuning F? What aliment should I use to get the numbers for tweaking?
My second question is about hooking the speakers to my amp. I have 2 of each of the below:
http://cgi.ebay.com/New-MKIII-Tripa...iers?hash=item3a522e7c13&_trksid=p3286.c0.m14
http://cgi.ebay.com/New-Version-MKI...yZ122650QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
I am not quite sure how to present a 4ohm load to my amp. I understand that wiring two 8ohm speakers in parallel will do this but where I get confused is how is this affected when you wire 2 10inch drivers AND a tweeter together to one channel as this was how I assumed Saturnus wired his boombox. Or should i use one tweeter and one woofer in parallel and then have 2 amps (4x15watts).
Also in my hunt for decent drives has been tricky as I am on a limited budget (mainly due to this being skateboard mounted and likely to be run into a wall or crashed and destroyed) can not find decent speakers with high sensitivity so will have to make do with less sound. What are the other quality for a good driver for this project? I have found a few contenders but one has only a 1.5mm xmax and the other 4mm.
The contenders at the moment are:
http://www.skytronic.com/rsc/doc/thielesmall_902127.pdf
902.423
902.420
902.376
feel free to make suggestions or any NZ leads for cheap drivers feel free to point me in the right direction as I have had little luck finding decent drives in New Zealand!
Thanks for the advice
Jestah
I am planning on building my own boombox to have a mobile skate soundsystem but a bit lost by the above... Could some one please give me a dummies guide to working this out...
Here is my shot in the dark so far:
Vb= Enclosure volume
Fb= The frequency of the enclosure
Now this is where I get lost, do just let WinISD do the first calculation and then tweak the numbers in the box volume and tuning F? What aliment should I use to get the numbers for tweaking?
My second question is about hooking the speakers to my amp. I have 2 of each of the below:
http://cgi.ebay.com/New-MKIII-Tripa...iers?hash=item3a522e7c13&_trksid=p3286.c0.m14
http://cgi.ebay.com/New-Version-MKI...yZ122650QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
I am not quite sure how to present a 4ohm load to my amp. I understand that wiring two 8ohm speakers in parallel will do this but where I get confused is how is this affected when you wire 2 10inch drivers AND a tweeter together to one channel as this was how I assumed Saturnus wired his boombox. Or should i use one tweeter and one woofer in parallel and then have 2 amps (4x15watts).
Also in my hunt for decent drives has been tricky as I am on a limited budget (mainly due to this being skateboard mounted and likely to be run into a wall or crashed and destroyed) can not find decent speakers with high sensitivity so will have to make do with less sound. What are the other quality for a good driver for this project? I have found a few contenders but one has only a 1.5mm xmax and the other 4mm.
The contenders at the moment are:
http://www.skytronic.com/rsc/doc/thielesmall_902127.pdf
902.423
902.420
902.376
feel free to make suggestions or any NZ leads for cheap drivers feel free to point me in the right direction as I have had little luck finding decent drives in New Zealand!
Thanks for the advice
Jestah
Hi Jestah,
Seems like you need to step away from the math and figure out the big picture first and see where that takes you.
Skateboard mounted? How big overall are you thinking? It's got to be stable, so it can't be too tall, or hang over the edges too much. The size of the box will help you figure out how many speakers of what size are even possible. Smaller boxes = smaller drivers, as there are specific relationships there that need to be looked at (that's what the math is for). Using two speakers per channel will need still more box volume.
And remember, you've got to have some room for the amp and a battery, which to have any life at all probably needs to be the size of your fist or somewhat bigger, and that's for one 12v-powered tripath. Getting more than 12v (15-18v) will be more complicated, as there's so many choices available for 12v power.
In general, small drivers are going to be less efficient than larger ones, but will probably sound better in a smaller box.
As far as coming up with a 4 ohm load, it is possible to get 4 ohm drivers, although these are a little rarer than the 8 ohm flavor. As you state, paralleling two 8 ohm drivers = 4 ohms. The kind of piezo tweeter and resistor that's being recommended does not meaningfully change the impedance presented.
If it were me, I'd figure out the box volume you can deal with for this type of skateboard sound system, and start looking at existing designs that use 1/2 of that volume--remember, you've got two channels. Somebody else has already done the hard work of figuring things out, and you should be able to use the basic plans, but change the poroportions as long as you're getting the same volume.
--Buckapound
Seems like you need to step away from the math and figure out the big picture first and see where that takes you.
Skateboard mounted? How big overall are you thinking? It's got to be stable, so it can't be too tall, or hang over the edges too much. The size of the box will help you figure out how many speakers of what size are even possible. Smaller boxes = smaller drivers, as there are specific relationships there that need to be looked at (that's what the math is for). Using two speakers per channel will need still more box volume.
And remember, you've got to have some room for the amp and a battery, which to have any life at all probably needs to be the size of your fist or somewhat bigger, and that's for one 12v-powered tripath. Getting more than 12v (15-18v) will be more complicated, as there's so many choices available for 12v power.
In general, small drivers are going to be less efficient than larger ones, but will probably sound better in a smaller box.
As far as coming up with a 4 ohm load, it is possible to get 4 ohm drivers, although these are a little rarer than the 8 ohm flavor. As you state, paralleling two 8 ohm drivers = 4 ohms. The kind of piezo tweeter and resistor that's being recommended does not meaningfully change the impedance presented.
If it were me, I'd figure out the box volume you can deal with for this type of skateboard sound system, and start looking at existing designs that use 1/2 of that volume--remember, you've got two channels. Somebody else has already done the hard work of figuring things out, and you should be able to use the basic plans, but change the poroportions as long as you're getting the same volume.
--Buckapound
tested...
I have tested a few different boxes already and don't worry about it being stable... I want it to be as unstable as possible as it will allow me to explore a new style of skating we are developing....
Here is some vids from our testing from about a year back, The first tests were just car head units driving 2 house speakers strapped to a mini skate and a 12v 7ah sla. Good sound at med volume but very power hungry!
http://neednotollie.com/surfin-stereo-wellington-sunday-skate
http://neednotollie.com/videos/sunday-skate-stereo-20
I have doing a LOT of reading and think that his thread has many features that are what i'm after. I have tested a kit set TD2004 amp with good results but decided to get a pre built tripath to extend my play time.
My last box was 2 sony xplode 2 way 6.5inch speakers mounted in 20L each (40L total box) with a small off the shelf 2inch port. No calcs as i could not find any specs for the speakers but was more testing to see how large we could go. This size is fun but i think i could go to a bit larger and still keep it under control.
The biggest draw back in my project is the fact that i have crashed these sound systems in the past and DESTROYED drivers so am restricted to trying to find speakers under $35nz each. This really limits my options... I dont think i will find any thing above 90db but over all volume can be a bit lower to save some cash.
could some one please help me understand how to tweak the number to get the correct box size for out door use?
I have tested a few different boxes already and don't worry about it being stable... I want it to be as unstable as possible as it will allow me to explore a new style of skating we are developing....
Here is some vids from our testing from about a year back, The first tests were just car head units driving 2 house speakers strapped to a mini skate and a 12v 7ah sla. Good sound at med volume but very power hungry!
http://neednotollie.com/surfin-stereo-wellington-sunday-skate
http://neednotollie.com/videos/sunday-skate-stereo-20
I have doing a LOT of reading and think that his thread has many features that are what i'm after. I have tested a kit set TD2004 amp with good results but decided to get a pre built tripath to extend my play time.
My last box was 2 sony xplode 2 way 6.5inch speakers mounted in 20L each (40L total box) with a small off the shelf 2inch port. No calcs as i could not find any specs for the speakers but was more testing to see how large we could go. This size is fun but i think i could go to a bit larger and still keep it under control.
The biggest draw back in my project is the fact that i have crashed these sound systems in the past and DESTROYED drivers so am restricted to trying to find speakers under $35nz each. This really limits my options... I dont think i will find any thing above 90db but over all volume can be a bit lower to save some cash.
could some one please help me understand how to tweak the number to get the correct box size for out door use?
Hey Jestah.
Interesting concept. As I see it, the Boominator design would actually suit your concept very well. You could just bolt the wheels directly to the case on the bottom and skipping the board entirely. The Boominator is designed to be center weighted. and you use a single 12V 7Ah battery instead of 2 it will also be very bottom-heavy so they'd be very stable with wheels directly bolted to bottom of the case.
The design is incredibly solid. I've actually dropped mine from shoulder height several times without nothing but a slight corner chip off of the plywood. It's practically indestructible in it's current design. And if you skip the solar panels, and add alu-corners from prof-style speakers, I think you'll find it hard to destroy even with a sledgehammer.
Interesting concept. As I see it, the Boominator design would actually suit your concept very well. You could just bolt the wheels directly to the case on the bottom and skipping the board entirely. The Boominator is designed to be center weighted. and you use a single 12V 7Ah battery instead of 2 it will also be very bottom-heavy so they'd be very stable with wheels directly bolted to bottom of the case.
The design is incredibly solid. I've actually dropped mine from shoulder height several times without nothing but a slight corner chip off of the plywood. It's practically indestructible in it's current design. And if you skip the solar panels, and add alu-corners from prof-style speakers, I think you'll find it hard to destroy even with a sledgehammer.
Help with seeing how a graph will sound....
I have decided to go with 4 6.5inch 8ohm drivers as they were cheapish and a friend had tested a set and was impressed by the sound quality. Here is a link to the secs:
http://www.surplustronics.co.nz/shop/product-902.423.html
http://www.surplustronics.co.nz/shop/product-900.207.html
I will be driving two in parallel with a single piezo tweeter by a 25w Tripath based amp from a 12v SLA
I plugged all the details into WinISD and here are my 3 options:
Yellow = standard quasi-butterworth as chosen by WinISD
Blue = a little less volume and slightly higher Fb for a touch more low end while still keeping around the same extension as above ( could this lead to a slightly one note boomie sound?)
green = the yellow box volume * Pi and the Fb by 1.414 hopefully resulting in a Qtc around 1.2 for better out door use.
what are peoples recommendations? My plan at the moment is to build a 40L box, split it in two and then fill the inside of the box with dead space as I need the overall size to be large enough for skateboard use and this will allow me to test all three above. I am leaning to the blue as my reading has lead me to believe that boosting the low base helps even out the sound that the human ear will hear but not sure how this will translate into the outdoor environment.
I am also worried about damaging my motors as they only have a Xmax of 4mm and this will be exceeded by any thing below 36hz at 25w. Should I use a high pass filter or should I be ok as this will only happen at 25w full power and I don't plan to drive this system that hard often.
I have decided to go with 4 6.5inch 8ohm drivers as they were cheapish and a friend had tested a set and was impressed by the sound quality. Here is a link to the secs:
http://www.surplustronics.co.nz/shop/product-902.423.html
http://www.surplustronics.co.nz/shop/product-900.207.html
I will be driving two in parallel with a single piezo tweeter by a 25w Tripath based amp from a 12v SLA
I plugged all the details into WinISD and here are my 3 options:
Yellow = standard quasi-butterworth as chosen by WinISD
Blue = a little less volume and slightly higher Fb for a touch more low end while still keeping around the same extension as above ( could this lead to a slightly one note boomie sound?)
green = the yellow box volume * Pi and the Fb by 1.414 hopefully resulting in a Qtc around 1.2 for better out door use.
what are peoples recommendations? My plan at the moment is to build a 40L box, split it in two and then fill the inside of the box with dead space as I need the overall size to be large enough for skateboard use and this will allow me to test all three above. I am leaning to the blue as my reading has lead me to believe that boosting the low base helps even out the sound that the human ear will hear but not sure how this will translate into the outdoor environment.
I am also worried about damaging my motors as they only have a Xmax of 4mm and this will be exceeded by any thing below 36hz at 25w. Should I use a high pass filter or should I be ok as this will only happen at 25w full power and I don't plan to drive this system that hard often.
Attachments
runing piezo in series
I have decided to externally mount the piezos above the main box to give the look of a loud speaker on a pole sitting above a speaker box. Just something a bit different but this runs me into some more problems!
For the balance and also to send as much sound forward and back I would like to split my box into a left and right and have 4 piezo horns but I am a bit worried that they will be to loud as well as needing both a left and right firing front and back (as most of the time when skating i will have riders in front of me or behind)
My first idea was to mount two but this could lead to funny sound as only one channel of the top end will be firing in the direction of the listeners. Is there any harm in wiring them in series (with a switch to by pass the back piezos when listing indoors?)
I have decided to externally mount the piezos above the main box to give the look of a loud speaker on a pole sitting above a speaker box. Just something a bit different but this runs me into some more problems!
For the balance and also to send as much sound forward and back I would like to split my box into a left and right and have 4 piezo horns but I am a bit worried that they will be to loud as well as needing both a left and right firing front and back (as most of the time when skating i will have riders in front of me or behind)
My first idea was to mount two but this could lead to funny sound as only one channel of the top end will be firing in the direction of the listeners. Is there any harm in wiring them in series (with a switch to by pass the back piezos when listing indoors?)
The green one looks absolutely perfect for outdoors use with a precisely 3dB peak at twice the tuning frequency. Perfect!
(Though I already knew it would be, as I spent quite a lot of time crunching the numbers)
As to which is the best piezo position for your use, I guess you can just experiment. Piezos are dirt cheap.
I you want to reduce the volume of a piezo you'll have to measure the capacitance though because it takes a series capacitor, not a resistor, to reduce the sound level.
(Though I already knew it would be, as I spent quite a lot of time crunching the numbers
)As to which is the best piezo position for your use, I guess you can just experiment. Piezos are dirt cheap.
I you want to reduce the volume of a piezo you'll have to measure the capacitance though because it takes a series capacitor, not a resistor, to reduce the sound level.
HI.
How is it going with your new Boominator Saturnus?..
Stalled due to lack of funds. I hope to start again soon and hopefully have it finished by April next year.