DIY Horn System with Plasma Tweeter
Hi guys, i need some help with specific measurments to construct open baffles.
I have the opportunity to put together a set of Corona Plasma tweeters with their matching Lansche compression horns. For the bass i want to stack 4 - 15" Eminence bass drivers per side (8 in total) in an open baffle arrangement.
The tweeters go down to 2.5khz, the midhorns (which are 50cm wide) go down to 500hz.
The idea is to put each 15"driver in a backless cube & stack the cubes on top of each other, like a tower with the horns mounted on the side. The bass is supposed to go down to 30hz.
Can someone help me with some the measurements of the cubes?
I'm hoping someone can advise what size they should each be and the help will be very much appreciated.
Looking forward to your feedback on this design.
Cheers.
Hi guys, i need some help with specific measurments to construct open baffles.
I have the opportunity to put together a set of Corona Plasma tweeters with their matching Lansche compression horns. For the bass i want to stack 4 - 15" Eminence bass drivers per side (8 in total) in an open baffle arrangement.
The tweeters go down to 2.5khz, the midhorns (which are 50cm wide) go down to 500hz.
The idea is to put each 15"driver in a backless cube & stack the cubes on top of each other, like a tower with the horns mounted on the side. The bass is supposed to go down to 30hz.
Can someone help me with some the measurements of the cubes?
I'm hoping someone can advise what size they should each be and the help will be very much appreciated.
Looking forward to your feedback on this design.
Cheers.
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It's going to be difficult to run the 'subs' as high as 500 hz without problems, because a U-frame has a resonance at a quarter wave-length (in practice the mode turns out a bit lower). An H-frame would be better in this configuration, but I'd suggest you use three of them in a U-frame up to about 100 hertz, where the fourth takes over.
The deeper the frame, the higher the efficiency. Maybe you could get away with 40 cm depth (in the configuration I proposed above), but you'll have to experiment with that.
The deeper the frame, the higher the efficiency. Maybe you could get away with 40 cm depth (in the configuration I proposed above), but you'll have to experiment with that.
Are you looking for physical measurements, or acoustic?
Keyser has a point about the u frame resonance - although it may be permissable to use the resonant portion of the driver's response. In my experience this hasn't been a problem.
BUT, up to 500 Hz is pushing it. Past the resonance, the frequency response will really degrade, particularly with multiple drivers - in fact I think you should seriously consider the effects of driver spacing - IMO, both crossover frequencies are too high with regard to the inter-driver spacing, particularly at 500Hz. My rule of thumb is that you want to keep the driver spacing less than half the wavelength of the XO frequency - so for 500Hz, that is about 1 foot. Your midrange response might end up looking abdominal. I highly recommend MJK's mathcad worksheets to help you determine your dimensions and desired acoustic response - I've tried lots of different software, and nothing is near as good as them.
I think my second point is that designing something on paper first is important, but acoustic measurements (semi-anechoic, and in room) are vital to a successful design. Doing a first time build is a long process, so don't kid yourself.
Third, there may be an issue with an omni tweeter and monopole mids and dipole bass (fairly irregular power response). Not sure if your tweeter setup will be omni though... I've always wanted to try the plasma tweeters though! I hope you success with them!
Keyser has a point about the u frame resonance - although it may be permissable to use the resonant portion of the driver's response. In my experience this hasn't been a problem.
BUT, up to 500 Hz is pushing it. Past the resonance, the frequency response will really degrade, particularly with multiple drivers - in fact I think you should seriously consider the effects of driver spacing - IMO, both crossover frequencies are too high with regard to the inter-driver spacing, particularly at 500Hz. My rule of thumb is that you want to keep the driver spacing less than half the wavelength of the XO frequency - so for 500Hz, that is about 1 foot. Your midrange response might end up looking abdominal. I highly recommend MJK's mathcad worksheets to help you determine your dimensions and desired acoustic response - I've tried lots of different software, and nothing is near as good as them.
I think my second point is that designing something on paper first is important, but acoustic measurements (semi-anechoic, and in room) are vital to a successful design. Doing a first time build is a long process, so don't kid yourself.
Third, there may be an issue with an omni tweeter and monopole mids and dipole bass (fairly irregular power response). Not sure if your tweeter setup will be omni though... I've always wanted to try the plasma tweeters though! I hope you success with them!
Thanks guys for your advice.
I'm looking for physical measurements.
The tweeter is a horn a and the mid horn has been matched by the manufacturer.
I"ll look into the H design and keep the spacing in mind.
I like the idea of using 3 of them at 100hz & have the other take over. Off to check out some mathcad.
Cheers.
I'm looking for physical measurements.
The tweeter is a horn a and the mid horn has been matched by the manufacturer.
I"ll look into the H design and keep the spacing in mind.
I like the idea of using 3 of them at 100hz & have the other take over. Off to check out some mathcad.
Cheers.
Might look over the Orion design that Sigfried published. He discusses these problems extensively.
Thanks tvrgeek, i have been reading his website the last few days, great info & has helped with making decisions.
Jut need to put together a prototype and try it out.
Hi guys,
I now have my tweeters and horns.
The baffles are not u or h design, the are solid & 150mm thick. The holes for the 4 -15" drivers are just bored through the baffle.
What do ya think, any comments on what the holes bored through will do for the 15"?
I now have my tweeters and horns.
The baffles are not u or h design, the are solid & 150mm thick. The holes for the 4 -15" drivers are just bored through the baffle.
What do ya think, any comments on what the holes bored through will do for the 15"?
This is much like my system. You should use eight fifteens per channel and run a pair of the 15's bellow the mid horn and treble down to around 80 Hz. Then use the remaining eight 15's in two four unit sub line arrays placed next to the main cabinets. triamp or quad amp with 4th order LR electronic crossover. I recommend better bass drivers for the mains though, your mid and treble is SOTA and the alpha 15's (is that the model?) are mediocre at best in low mid and upper bass. Four will do OK in an OB for bass.
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Thanks for that,
Ok, then i will put together a stiff panel with aluminum and ply so the energy is released.
I am also thinking about bracing the magnets at the rear and having the 4 drivers isolated from the front baffle.
Ok, then i will put together a stiff panel with aluminum and ply so the energy is released.
I am also thinking about bracing the magnets at the rear and having the 4 drivers isolated from the front baffle.
I meant to say six 15's per channel, two on the baffle with mid and treble above them used down to 80 Hz and four on a separate line array baffle 80 and down. The two used with the mid and treble should be very high quality for the low midrange and upper bass with QTS around .5. Aluminum and ply should work great.
Thanks,
I did a mock set up and the system looks great with the horn on top, the tweeter & the two 15" underneath.
I'm thinking of ditching the Eminence and looking towards something like the AE 12" or 15".
You are right, i should go better quality 15" drivers.
Cheers.
I would stick with fifteens. Twelves won't move as much air, normally have more dynamic compression and won't have the directivity of the 15's - I think AE 15's will sound just wonderful in the low mid and upper bass. 🙂
I spoke to a commercial speaker designer today, he has used the Eminence before & claims it can still do a great job in either OB or conventional box.
But then there is the whole thing about not having box colouration in the first place.
I'll keep thinking about the bass, in the mean time i now have someone who can build me a crossover.
But then there is the whole thing about not having box colouration in the first place.
I'll keep thinking about the bass, in the mean time i now have someone who can build me a crossover.
Hi 3GGG,
It has evolved,
No longer bothering with the OB.
No not finished but it has developed into a 4 way horn system and is set up like an avantgarde trio.
Plasma tweeter, 50cm mid horn, 100cm midbass horn and lascala basshorn.
The frequency ranges for each driver 35-160-400-2500-150,000
The plasmas are amazing to listen to, i'm making arrangements to paint the horns candy apple red and i'm just working out the cost of the stands.
When it is done i will post pictures - hopefully in a couple of months.
Cheers,
It has evolved,
No longer bothering with the OB.
No not finished but it has developed into a 4 way horn system and is set up like an avantgarde trio.
Plasma tweeter, 50cm mid horn, 100cm midbass horn and lascala basshorn.
The frequency ranges for each driver 35-160-400-2500-150,000
The plasmas are amazing to listen to, i'm making arrangements to paint the horns candy apple red and i'm just working out the cost of the stands.
When it is done i will post pictures - hopefully in a couple of months.
Cheers,
Just read about some candy apple red horns on another forum! Same person maybe 🙂
Your build sounds incredible, what driver are you using for the 50cm and 100cm horns?
Your build sounds incredible, what driver are you using for the 50cm and 100cm horns?
Likely given that you are also in Aus.
I'm making arrangements to have them painted.
Driver for the 50cm is a Lanche compression driver (it is actually a 2" B&C compression driver)
The 100cm is heading towards being a 8" or 10"PHL driver, they came up best on the sim.
The 15" lascala is brand new from Klipsch.
I'm making arrangements to have them painted.
Driver for the 50cm is a Lanche compression driver (it is actually a 2" B&C compression driver)
The 100cm is heading towards being a 8" or 10"PHL driver, they came up best on the sim.
The 15" lascala is brand new from Klipsch.
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