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** Pi chart request ** [message #47891] Thu, 06 October 2005 09:31 Go to next message
j.luis cruz . is currently offline  j.luis cruz .
Messages: 154
Registered: May 2009
Master
Where I can see the spl charts of your models Wayne ..thanks

Re: ** Pi chart request ** [message #47894 is a reply to message #47891] Thu, 06 October 2005 16:45 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18784
Registered: January 2001
Illuminati (33rd Degree)

See www.PiSpeakers.com/Measurements. They're just internal R&D measurements, but if you're interested, they're there.


Re: ** Pi chart request ** [message #47895 is a reply to message #47894] Thu, 06 October 2005 17:15 Go to previous messageGo to next message
spkrman57
Messages: 522
Registered: May 2009
Illuminati (1st Degree)
Looks like the Delta 10 has the best efficiency. I have that driver and Bill Epstein assembled my horns(after I screwed it up) and will give it a shot.

I am going to try a lame experiment and see if a JBL 2242 will reach up to 200hz - 300hz to meet the horn used with subwoofer plate amp with 40hz - 160hz variable crossover internally.

Since 160hz to 320hz would be just one octave, should be interesting to see what doesn't make it as my room is small and everything loads quickly in my system. Bass and mids have no problem and usually have to be padded more than most folks would use.

I am curious on what the impedance curve looks like if you use a 18" and 10" both being 8 ohms makes the total system look more like a 4 ohm at the bottom octaves, does it not?

Ron mad backyard audio scientist!!! LOL!

Re: ** Pi chart request ** [message #47896 is a reply to message #47895] Thu, 06 October 2005 17:59 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18784
Registered: January 2001
Illuminati (33rd Degree)

The JBL 2242 will work very well in a system like this. That, or a 2241 or 2245, is what is used in Professional Series seven π-18 loudspeakers. I understand you are concerned that the plate amp will rolloff the upper response, but I think you might be able to modify it to increase the crossover frequency.


Re: ** Pi chart request ** [message #47897 is a reply to message #47896] Thu, 06 October 2005 18:07 Go to previous messageGo to next message
spkrman57
Messages: 522
Registered: May 2009
Illuminati (1st Degree)
Wayne,

I am using a powered sub plate amp for my 2242, I asked about if building the system with the 18" 8 ohm driver and 10" horn driver if they working together lower in the total impedance at the lower octaves!

I would have 2 2242's, but right now I have to get one fixed as it has a flapping surround and I want to fix it before it should get worse.

By the way, I set up a friend with a Eminence 18" omega and compared to the JBL 2242 it plays as loud, but I don't hear the finesse of the bass like the JBL can do.

But for 4 times the price, the JBL should do better!

Ron

Re: ** Pi chart request ** [message #47898 is a reply to message #47897] Thu, 06 October 2005 22:10 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18784
Registered: January 2001
Illuminati (33rd Degree)

Impedance at low frequencies will drop at some points, but will rise again at the resonance modes. At these frequencies, shunt impedance will reduce Zmax and it will tend to remain more constant. It's a consequence that acts in your favor.


Re: ** Pi chart request ** [message #47901 is a reply to message #47898] Fri, 07 October 2005 07:10 Go to previous messageGo to next message
spkrman57
Messages: 522
Registered: May 2009
Illuminati (1st Degree)
Wayne,

Have you ever run a impedance curve test to see? Would be quick and easy with WT2 from PE.

I take it from your last post that the staggered impedance of the 2 drivers flatten out the impedance and that there is probably only a few occurences where the impedance would drop below say 6 ohms, right???

It also seems if the above is true, then a zoebel is not required which reduces the parts count also. That would be very convenient and save some $$$ in the long run.

Now it seems the only problem I have to breadboard this system is to move things around in the house(easier said than done!) The one thing different for me will be trying the JBL 2242 18" in a 9 cubic ft box tuned to 30hz, I was the lucky person in the right place and the right time to get these cabinets built by a "JBL" guru who wants to remain anonymous. They have 2' x 4' bracing and 2 x 6" dia by 13.5" ports. This driver is currently doing sub duty and kicks butt! I can never listen to a 12" or lame 15" sub ever again!!!

Later, Ron

Re: ** Pi chart request ** [message #47907 is a reply to message #47901] Fri, 07 October 2005 17:14 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18784
Registered: January 2001
Illuminati (33rd Degree)

There is no Zobel in the seven π loudspeaker.

seven π loudspeaker impedance chart

Re: ** Pi chart request ** [message #47979 is a reply to message #47907] Fri, 14 October 2005 06:20 Go to previous message
spkrman57
Messages: 522
Registered: May 2009
Illuminati (1st Degree)
Thanks Wayne,
It seems that the lowest impedance drops no lower than 5 ohms which should be okay for most amps!
Ron

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