3 way Pa Speaker Project

[altsouza]

Hello Guys,

Recently assembled a Small PA (small Parties, DJ) for Personal use, but not liked it.
It has a Selenium 15pw7 Woofer, Selenium St220i Driver and Passive 2 way Crossover.
I Amplify it with a QSC GX3 Power Amp.
I'm thinking about redoing the cabinet, making a 3-way design with the inclusion of a Selenium D405 Phenolic Driver for Midrange.
I Use this driver in the Cornscala (Bob Crites) Speaker for Domestic use and really like the result.
So I want to test it in this nex speaker Project for Pro Audio use.
In this case I will use a 3-way external crossover (Jriver+Focusrite Sound Card) for Bass / Mid / Treble.
Can anyone have a 3-way PA Project Papers??
Any help will be wellcome!
Thanks
Altsouza

 

[conanski]

The best sounding 3-way PA cabs I have heard use an 8" cone mid crossed at 500hz and 5khz, use a sealed back driver and you won't have to redesign the cabinet unless there is literally no room on the baffle to fit the driver.

 

[altsouza]

Hi,
Thank you.
There is no space between the woofer and the small horn to install the 8" cone mids.
Do you really think the 8" cone woofer be better than the Huge D405 driver??
Thanks


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[RAW]

I built these several years ago now with my brothers band.I had them in the shop for a day and they all worked on the speakers to build and finish them.The end result they dropped JBL horns and bins.These are the mains they have used in hundreds of jigs now.
Original was APT-50 then switched to the new D2500-Ti tweeter.Far better than the APT-50.
Beta 8
Kappa 15
I did not take a lot of pictures but here is a link to a few.

PRO monitors - a set on Flickr

For bass built a pair of them.

 

[conanski]

There is no space between the woofer and the small horn to install the 8" cone mids.

Well.. do you realize the D405 requires an equally massive horn to safely operate down to a 500-1khz crossover? You can't just bolt it to the little horn the 1" driver is currently attached to.

 

[altsouza]

Thank you Raw, good photos.

HI conanski,
I am going to build another Cabinet to acomodate de D405 driver.
I am looking for projects to build it.
The 8" Cone is also a option.
Thanks
Antonio

 

[turk 182]

are you looking for plans to make a single box 3-way because separate boxes would be easier to handle as well as being lighter.
a folded or tapped horn for bass and a mid /high (containing your proposed 8 inch mid and horn)
something like a Cubo 15 for sub and an MT122 as a top
googling either of these should produce the results your looking for!(if not i should be able to forward you the right links)

 

[altsouza]

Hi Turk,
I already have a separate 15" sub.
I would prefer to build a single 15" + 8" + Tweeter Cabinet.
Do you have any plans fot it?
Thanks
Antonio

 

[turk 182]

not a specific plan but designing or adapting an existing plan to suit your purpose is possible.
are you looking for something horn loaded or simply direct radiator?
what type is your existing sub? making a suggestion for a mid high design without knowing what sub you have could lead to the wrong solution!
how are your carpentry/woodworking skills a horn loaded top would require advanced skills while a simple bass reflex can be cobbled together fairly easily with basic tools

 

[altsouza]

Hi Turk,
The Sub is a regular Pro Audio 15" Sub - Band Pass Sixth Order.
For now I want to focus in the Main Cabinets. The Subs I can modifiy later next year.
For partical purposes I want a Single unit Cabinet. I already have a 15"+Titanium Driver Small Trapezoidal Cabinet, but I do not like it.
I want to build another 3 way one, and add a 8" Mid Cone or a large D405 Phenolic Driver for the mids. Maybe the 8" cone would be more eficient and economical.
I will active tri amp it using Jriver media center+Focusrite Sound card and QSC Power Amps.
I can build the Cabinets using 3/4 Naval laminate or MDF, and it can be Bass Reflex for easy built.
I need only the Plans.
Thanks
Antonio

 

[conanski]

What is it about the sound of your 15" 2-ways you don't like? I couldn't find any info on the ST220i is that a standard compression driver or a super tweeter? What are you using for a crossover on these?

Horn loaded mids are loud and efficient but they are often very harsh sounding, in comparison cone mids are less efficient but are still usually more efficient than low frequency drivers so it's not a problem to get a balanced sound.
In the past there were lots of 3-way cabs built with the design below, It's relatively easy and compact but the location of the mid and hi drivers is less than ideal.

Most modern 3 way designs put all drivers in a vertical column, human hearing is less sensitive to comb filtering in the vertical axis than in the horizontal axis, and placing the mid and high freq drivers at the very top makes it easier to get them overhead where they won't get blocked by bodies.

An externally hosted image should be here but it was not working when we last tested it.

 

[altsouza]

Hi Conanski,
There is no Bass, and the Highs are too bright.
I am using a 2 way Passive Crossover:
Freqüêncy: 1,8 KHz @ 4 ou 8 Ohms (woofer)
Máxima potência: 370 W (rms)
Tipo de Filtro: Linkwitz-Riley
Ordem: 2ª-ordem - 12dB/8ª -driver ; 1ª ou 2ª ordem-woofer

I liked the Modern 3 way cabinet. Do you have Plans for it?


Sorry, the driver is D220ti ans Here are the specs:
Impedance 8ohms
Frequency response @-6 dB 1,000 to 21,000 Hz
Throat diameter 1"
Magnet weight 24oz (675g)
Housing material Plastic
Voice coil material Kapton®/CCAW
Horn connection Screw-on

The Woofer is JBL Selenium (made Brazil)
Diâmetro 15"
RMS 300W
Programa Musical 600W
SPL 1W@1m 97dB
Resp. Frequencia @-10dB 40 a 4.500Hz
Frequência de ressonância 45Hz
Diâmetro da bobia 60mm
Peso do imã 1.300g
Impedância 8ohms

And I am planning to Add this 8" Cone Mid Bass:
Impedância Nominal 8 Ohms
Resposta de Frequência 68~5.000 Hz
Freq. Mínima de Corte 150 Hz
Sensibilidade 1W/1M 95,5 dB
Potência RMS 200 w
Potência de Programa 400 w
Diâmetro da Bobina 2"


PARÂMETROS TS
Frequência de Ressonância Fs 59 Hz
Resistência da Bobina Re 5,7 Ohms
Fator de Qualidade Total Qts 0,36
Fator de Qualidade Mecânica Qms 4,90
Fator de Qualidade Elétrica Qes 0,40
Volume equivalente do Falante Vas 36 L
Área efetiva do Cone Sd 0,028 m²
Deslocamento Máximo Xmax ± 5,0 mm


Thanks

 

[turk 182]

how big is the box their in now and is it vented or sealed you mentioned that you had them in a trapezoidal enclosure?
a series resistor to the horn driver to "pad" the level from the x-over could help but if your planning to implement an active crossover that a moot point.
i tried to copy an image of a design for a horn loaded 3 way designed for Selenium drivers but wasn't successful (i'm not the most computer savy) it referenced as PAS3MA3 i don't know if googling that will lead you to the plans i'm thinking of.

 

[altsouza]

Hi Turk,
The Speakers are small , around 80cm H, 43cm w, 50cm d.
The PAS3MA3 Design are good, but would be dificult to build. I would prefer a regular Box like the example Conanski posted, the Modern 3 way design.
Antonio

 

[turk 182]

so sealed or ported?

 

[altsouza]

Ported. two small holes under the woofer

 

[conanski]

Hi Conanski,
There is no Bass, and the Highs are too bright.

Bass with PA drivers requires very large cabs so there is almost no point using a 15" like this in a "fullrange cab".. I won't use anything bigger than a 12" for example and I don't even try to make them produce any serious amount of bass. The solution to that is to add subs.

I am using a 2 way Passive Crossover:
Freqüêncy: 1,8 KHz @ 4 ou 8 Ohms (woofer)

Sorry, the driver is D220ti ans Here are the specs:

That is a very good compression driver.. I have the older version (D210Ti) so I know it is capable of good sound. What I don't see is a crossover component known as an L-pad, it is a resistor network that goes between the crossover high output and the CD to reduce it's output so it better blends with the low freq driver output. In this case you need 9db of attenuation, go to the link below and input 8ohm, 9db, and 50w and then buy some 15w and 25w power resistors in values as close as you can get to the values indicated and install them in your speakers as indicated. L-Pad (Driver Attenuation Circuit) Designer / Calculator

 

[wg_ski]

Bass with PA drivers requires very large cabs so there is almost no point using a 15" like this in a "fullrange cab".. I won't use anything bigger than a 12" for example and I don't even try to make them produce any serious amount of bass. The solution to that is to add subs.

Depends what you're trying to acheive. Full range 15" 3 way cabs are the bomb for getting 50-60 is Hz "bass" at moderate levels - more than a 10 or 12 that's rolling off like a brick wall at 80 and can't take any bass boost. One amp, one pair of speakers, just plug and play. That's why EON15's are so popular, but I prefer a good 3 way DIY and separate amp. The other instance is if you're already using subs, especially TH's that can't cross above 80-ish and your program material requires a wide mid-bass (80-200 Hz) hump that the subs aren't covering. 12's will struggle, 15's won't. Kick bin horns won't either, but that's a more complex setup.

My mid size DJ rig uses 2x12" tops, but the only low end boost I want is below 50 so the 12's are fine on top. Trying to run a band through the same rig doesn't work as well and out come the 15" 3 ways (with the same subbage). The 3 ways are fine by themselves if all I am doing is background music (the 12's don't have enough bass).

 

[conanski]

The Speakers are small , around 80cm H, 43cm w, 50cm d.

With an 80cm x 43cm(31" x 16.5") baffle how is it you don't have enough room to install an 8" mid? How big is the horn?

 

[altsouza]

Thank you Guys,
Conanski, I am going to build or buy a new cabinet, and I will add a 8" cone.
I have a few more questions:
1) I can buy this cabinet (photo) for us$300 pair. This cabinet is 1x15 1x12. 1xdriver and one tweeter.
I can make some modifications to acomodate a 8" cone, and skip the tweeter port. What do you think?
2) the same manufacturer makes a 2x15 plus driver. What are the sonic/aplication diferences between 3 way and 2x15+driver?

The cabinets are well made and easier for me. I will save time!!

Thanks

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