Reflex Designs for PD/PDN 2450

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mclsound

Member
Joined 2007
Well the band is wanting to be unique so we can get
2...PD 2450
2...PDN 2450

Specs seem the same just weight difference. ..
For ease of building can do 10-16ft3/driver front loaded with vent..
We will mate these with 8 JBL 2241 tuned to 40hz allowing these 4 badboys to handle the heavy 30's hz..
Power will be Lab Gruppen FP6400
I have 2 FP6400 currently


Any ideas or comments welcomed
 
weltersys

weltersys

Member
Joined 2008
mclsound said:
Well the band is wanting to be unique so we can get
2...PD 2450
2...PDN 2450

Specs seem the same just weight difference. ..
For ease of building can do 10-16ft3/driver front loaded with vent..
We will mate these with 8 JBL 2241 tuned to 40hz allowing these 4 badboys to handle the heavy 30's hz..
Power will be Lab Gruppen FP6400
I have 2 FP6400 currently


Any ideas or comments welcomed
Click to expand...
The 2241 has an Fs of 35 Hz, an Xmax of 7.62 mm, Vas of 311 L.
The PDN 2450 has an Fs of 31.48, an Xmax of 10.62mm Vas of 369.15L, not a whole lot of difference.

Given the same tuning, (with a larger box) the approximate 3 dB Xmax advantage of the PDN 2450 (requiring twice the power) would only gain 3 dB overall, hardly noticeable.

If you tune them lower, say 32 Hz, their output level will drop at least 3 dB, so their LF output level in the 32 Hz range will be about 6 dB less than the 2241 SPL in the 40 Hz range, about half as loud.

Did you measure excursion to see if your present box Fb actually is actually 40 Hz?
Why not tune the 2241's to 35 Hz if you want more "heavy 30's"?
 
GM

GM

Member
Joined 2003
Just happened to be looking at 24" today for lower tunings, so FWIW, scaled the PD2450 TH back to its published Fs and compared it to a vented alignment of the same total net Vb [Vb+Vv] = ~334.4 L using R.Small's recommended ~865 cm^2 minimum vent area for an unflared pipe, though didn't take the time to convert the rectangular duct to an equivalent [multiple] pipe vent, so the BR's net Vb might be more in reality if you go this route.

GM
 

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M

mclsound

Member
Joined 2007
Thanks for the reply guys
GM..got 4...2450 coming...I figure 16 ft3 each should do the job..and 1900w each from the 2 lab gruppen fp6400 should suffice..

The 2241 are not the best for lower 30s but good for 40s...
I looked at other 18s but at 30 hz they all average 80db and the 2450 around 91..92db and over 100db at cutoff of 80hz
Nice measurements
 
C

chrapladm

Member
Joined 2010
Well the 2240H can be reconed as a 2245H which would be killer for a subwoofer if you have the room. Cheapest option for a low Fs subwoofer I can think of in Pro audio. I will be looking at getting some 2240's in the future also.:D

The 2245H was what I was trying to compare all my purchases against. PS100 was the closest but I can get a 2240H for less money, so the PS100 was my best option for my budget.
 
M

mclsound

Member
Joined 2007
Yes
It is a 3mnth wait for more
And the savings were nice...enough to purchase 10 5x5 sheets of 1" baltic birch and 5-3/4" sheets...handles..wheels...speakon plates..***not sure about grills yet????
I also got 6 Fane 15" Sovereign 600N for my tops to go with my JBL 2446..
Im looking at the B&C me60 horn to mate with them for a horizontal array build (thats a new thread)
Should have it all next week. .
 
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