Hi guys! 🙂
i'm here to show you my new project: a PA system with a super performance/cost quotient.
target:
- f. response: 45hz(f3) - 16000hz circa
- hi max spl (near 140dB)
- stack use (0.5phi)
- low cost
after some ideas i have realised that to contain cost i have to create a 2way system:
- low frequency: 45hz to 500hz (if it is possible highest, like 800hz but i will test it)
- hi frequency: 500hz (800hz)to the highest possible frequency
- eventually piezo tweeters
to have a very high SPL i decide to use horns: frontloaded horn is probably impossible (due to freq. range), so i will project a rearloaded horn, i don't really like rearhorns but in this case i will use! 🙂
the driver that, in my opinion, has the best performance/cost quotient is the Skytronic 902.442:
http://export.skytronic.com/product/product.php?s=902.442
a cheap 12" whit big voice coil (100mm) and good t&s for a horn.
Here is the project using HornResp:
and here is the project using AJhorn:
GOOD! (in my opinion) 😀
i would create 4 scoopbin, so i can create a stack and work in 0.5phi... probably i can get 140dB whit only 1.2KW from this bass system...
for the high frequency i probably use this compression driver (but i don't know if they can go to 500hz):
http://www.usblaster.com/Products/DJ ⁄ Pro Audio/Speakers PA/Compression Horn Drivers//USB 387
or this:
http://www.usblaster.com/Products/DJ ⁄ Pro Audio/Speakers PA/Compression Horn Drivers/USB 384
(probably the first)
in my opinion i need 4 compression driver with few watts: so i can improve the durability of the system.
what do you think about this crazy project?
😀 😀 😀 😀
i'm here to show you my new project: a PA system with a super performance/cost quotient.
target:
- f. response: 45hz(f3) - 16000hz circa
- hi max spl (near 140dB)
- stack use (0.5phi)
- low cost
after some ideas i have realised that to contain cost i have to create a 2way system:
- low frequency: 45hz to 500hz (if it is possible highest, like 800hz but i will test it)
- hi frequency: 500hz (800hz)to the highest possible frequency
- eventually piezo tweeters
to have a very high SPL i decide to use horns: frontloaded horn is probably impossible (due to freq. range), so i will project a rearloaded horn, i don't really like rearhorns but in this case i will use! 🙂
the driver that, in my opinion, has the best performance/cost quotient is the Skytronic 902.442:
http://export.skytronic.com/product/product.php?s=902.442
a cheap 12" whit big voice coil (100mm) and good t&s for a horn.
Here is the project using HornResp:
An externally hosted image should be here but it was not working when we last tested it.
and here is the project using AJhorn:
An externally hosted image should be here but it was not working when we last tested it.
GOOD! (in my opinion) 😀
i would create 4 scoopbin, so i can create a stack and work in 0.5phi... probably i can get 140dB whit only 1.2KW from this bass system...
for the high frequency i probably use this compression driver (but i don't know if they can go to 500hz):
http://www.usblaster.com/Products/DJ ⁄ Pro Audio/Speakers PA/Compression Horn Drivers//USB 387
or this:
http://www.usblaster.com/Products/DJ ⁄ Pro Audio/Speakers PA/Compression Horn Drivers/USB 384
(probably the first)
in my opinion i need 4 compression driver with few watts: so i can improve the durability of the system.
what do you think about this crazy project?
😀 😀 😀 😀
My opinion - though you may not not want to hear it is:
A 2 way PA with a clean output of 140db is a lofty goal. I won't say it's impossible, but you want it cheap as well?
I am unfamiliar with those drivers you mentioned, nor have I seen any feedback on them... Based upon the pdf specs:
The 12" driver has only a 4mm excursion - Excursion limited and Insufficient to generate that sort of SPL before mecahnical damage or thermal failure, I'm guessing.
It's been my experience that a PA made from cheapest parts can not be made to sound good, and will not be very durable and robust.
There is a huge sonic difference in a PA made with cheap parts and one made with name brand drivers.
You pay a lot of money for a driver like a 2206 or a 2226, but after over 8 years and thousands of watts they still sound better than new OEM drivers.
I repair drivers and so I would rather repair a used/damaged ( cone tear etc ) JBL then buy a new OEM despite price.
A 2 way PA with a clean output of 140db is a lofty goal. I won't say it's impossible, but you want it cheap as well?
I am unfamiliar with those drivers you mentioned, nor have I seen any feedback on them... Based upon the pdf specs:
The 12" driver has only a 4mm excursion - Excursion limited and Insufficient to generate that sort of SPL before mecahnical damage or thermal failure, I'm guessing.
It's been my experience that a PA made from cheapest parts can not be made to sound good, and will not be very durable and robust.
There is a huge sonic difference in a PA made with cheap parts and one made with name brand drivers.
You pay a lot of money for a driver like a 2206 or a 2226, but after over 8 years and thousands of watts they still sound better than new OEM drivers.
I repair drivers and so I would rather repair a used/damaged ( cone tear etc ) JBL then buy a new OEM despite price.
probably 140dB is too high for my application... and this is impossible for this kind of product...
I will test the woofer and the driver, after this i will decide...
🙂
thank you for your opinion!
🙂
I will test the woofer and the driver, after this i will decide...
🙂
thank you for your opinion!
🙂
By the time you reach 140dB your nose starts to bleed.
I agree with HK, 140 is a bit lofty. I run 6 15" horn loaded Selenium PA woofers plus 2 horn mids and 2 horn tweeters and expect a clean 125 dB with 1.5K of power.
Tell us what these are for, maybe we can help.
I agree with HK, 140 is a bit lofty. I run 6 15" horn loaded Selenium PA woofers plus 2 horn mids and 2 horn tweeters and expect a clean 125 dB with 1.5K of power.
Tell us what these are for, maybe we can help.
i have calculated a theorical spl at 1 meter in a 0.5phi emission...
so real 115-120dB are enoght! 🙂
i would create this system for a carnival wagon...
🙂
so real 115-120dB are enoght! 🙂
i would create this system for a carnival wagon...
🙂
Forum member Davygrvy built 6 horns each with an Eminence HL10 ( Total Driver cost $780 ). These horns formed a fairly small stack.
And when given enough power produced painful SPL.
I used to set up a parade float sound system myself, and I'm guessing his stack would fit your carnival wagon system.
But not as a 2 way.
And when given enough power produced painful SPL.
I used to set up a parade float sound system myself, and I'm guessing his stack would fit your carnival wagon system.
But not as a 2 way.
HK26147 said:
my metod to have an approx of the max thoerical output,
An externally hosted image should be here but it was not working when we last tested it.
i use it to note the difference between different thorical project...
isn't correct but for approx the difference between project is good...
🙂
another simulation...
🙂
140dB was refered to these simulations...
😉
🙂
An externally hosted image should be here but it was not working when we last tested it.
🙂
140dB was refered to these simulations...
😉
🙂
Does that 1st simulation graph you just posted assume a no Xmax limit of 99mm?
The prediction of the 2nd graph does not seem reasonable to me with a 4mm Xmax driver that will probably start to experience thermal compression @ 1/10 power and will have 2.5db loss @ 1/2 power, as typical for a pro driver
The prediction of the 2nd graph does not seem reasonable to me with a 4mm Xmax driver that will probably start to experience thermal compression @ 1/10 power and will have 2.5db loss @ 1/2 power, as typical for a pro driver
I have yet to hear a 2way PA that meets your goals, or an individual horn driver or horn/cab that would give a good response over 5 octaves for a high SPL PA.
Realistically I try to give each PA driver section a bandpass of approx 3 octaves, so each section can be optimized for it's bandpass, and any high frequency anomalies from each horn are filtered out electronically.
I don't have a pic of David's sub stack, but if you msg him, I'm sure he would sent you the couple I saw. I think his stack was up for sale.
Here are a couple pics of my BFM AutoTuba (16" wide) sixpack.
and the response chart
They calculate to 134dB(SPL) @ 40Hz in half space at 300W input each. I chose to make six little horns to run as a group due to space restrictions. Six HL10C drivers in much bigger horns will of coarse be more efficient and deeper, but this was to solve a space problem and compromised on using more drivers, thus more power, to achieve the goal.
I don't think it is realistic to do a loud full-range system as a 2-way. Even 3-way takes compromises for beamy midbass drivers run too high.
An externally hosted image should be here but it was not working when we last tested it.
and the response chart
They calculate to 134dB(SPL) @ 40Hz in half space at 300W input each. I chose to make six little horns to run as a group due to space restrictions. Six HL10C drivers in much bigger horns will of coarse be more efficient and deeper, but this was to solve a space problem and compromised on using more drivers, thus more power, to achieve the goal.
I don't think it is realistic to do a loud full-range system as a 2-way. Even 3-way takes compromises for beamy midbass drivers run too high.
@ davygrvy:
thank you for the info!
good project the autotuba of BFM, is a phi/8 horn and in a stack can sound very smooth and goes low...
my initial project was developed to reduce costs:
- max 4 woofer--> 0.5phi design
- max 4driver (in particoular i find this driver with a low low cost! [circa 30€])
- eventually piezo...
to extend the frequency of the woofer, enought for use the driver, i choosed a rearloaded bass horn: 40hz * 2^4 = 640hz (4octaves)
mid horn: 325hz (circa) * 2^4 = 5600hz
so:
12": 40hz to 500hz circa
mid driver: 500hz to 5000hz circa
piezo: 5000hz to 20000hz
i have choose 4 octaves because i readed that use horns for 3 octaves over the fb of the horn is wonderful for HIFi, 4octaves is for a compromise and 5octaves is not good!
but i have to test the driver and the woofer...
if they are **** I can create a system like yourse...
🙂
thank you for the info!
good project the autotuba of BFM, is a phi/8 horn and in a stack can sound very smooth and goes low...
my initial project was developed to reduce costs:
- max 4 woofer--> 0.5phi design
- max 4driver (in particoular i find this driver with a low low cost! [circa 30€])
- eventually piezo...
to extend the frequency of the woofer, enought for use the driver, i choosed a rearloaded bass horn: 40hz * 2^4 = 640hz (4octaves)
mid horn: 325hz (circa) * 2^4 = 5600hz
so:
12": 40hz to 500hz circa
mid driver: 500hz to 5000hz circa
piezo: 5000hz to 20000hz
i have choose 4 octaves because i readed that use horns for 3 octaves over the fb of the horn is wonderful for HIFi, 4octaves is for a compromise and 5octaves is not good!
but i have to test the driver and the woofer...
if they are **** I can create a system like yourse...
🙂
So it isn't really a 2 way...
IHMO: If you try to driver that compression driver hard it will blow quickly.
That compression driver strikes me as a cheap knockoff of similar screw-on drivers from Eminence etc.
It doesn't have a published Fs, nor a graph of frequency response to know how it performs near it's Fs.
And it's spelled KAPTON, not CAPTON ( that to me is a red flag when a manufacturer doesn't provide performance measurement and can't proofread it's copy )
Even with an active xover with an aggressive slope rate (48db) I would not attempt a 500hz xover and then drive it as hard as you intend.
As far as the use of piezo: The members of the BF forum ( David just mentioned ) use arrays of piezos. For the most part they find they work fine, with accepted limitations...
It takes a bunch of them ( dozens ). They need EQ. They should be limited to 27V max for protection. They need to be implemented with stability resistors to keep amps from oscillation. To also protect them and get the most SPL out of them, they need to have a xover ( regardless of sales hype ).
SEE DIYAUDIO wiki on this:
Those individuals who really require high SPL ( on the level you desire ) found piezos unacceptable and switched to compression drivers ( BMS drivers mostly ).
Things to consider...
Syd
HK26147 said:
yes, the driver is an unknown quantity... probably i will use some 6" or some 8" horn loaded for the mid...
but i will take one driver, i will analyze the impedence, i will crox to 500hz... sound... i will try if it broke down or not 😉
it's cheap, no problem... 🙂
yes piezos has limits but also advantage like, manly, no power loss... in particoular an array of piezos, lots of time, could help... i know that they need a good EQ and a specific filter but, fortunately, i haven't problems in it... 🙂
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