Hi; Looking for a pair of 4520bk. Which woofers are best? I have two 3182 crossovers for dual bass....should I look for 2440,2441 2482 375...and which croos for adding 2405s?
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Hi; Looking for a pair of 4520bk. Which woofers are best? I have two 3182 crossovers for dual bass....should I look for 2440,2441 2482 375...and which croos for adding 2405s?
Hi,
Here's a ( very ) good thread to read ( regarding those scoops );Oh No!>>>> JBL 4520 Related
:)
BTW, the 2226h or 2225h is generally the speaker of choice for these BLH ( back loaded horns ) / though one could easily go searching for a newish alternative ( non-Lansing product ) that has an EBP ( energy bandwidth product ) even higher than 122 or 130 (hz) .
This ( greater EBP ) will offer more "snap" ( as well as slightly higher efficiency ).
Hands down, the 130A or 2220 series is the best choice for a rear loaded horn, or straight axis or compression type.Quote:
Originally Posted by Earl K
"EBP ( energy bandwidth product ) even higher than 122 or 130 (hz)"
Actually, EBP stands for Efficiency Bandwith Product, which is not a frequency, but a ratio between fs divided by Qes. Loading a woofer in a rear loaded horn such as the 4520 or 4530 with an EPB that of the 2225 or 2226 will result in weak bass. The reason, is that the chamber of the 4520 is too small for those drivers, which means the throat area is also out of proportion. As is the chamber for the 4530 is also too small. The 2226, and especially the 2225 are two woofers I would never consider for any horn design. I know JBL loaded the old theater horns with the 2225 as an option, but one must consider the company had very few woofer options back then. For example; why the company chose to load the Paragon with the LE15 has to be the mother of all bone head moves, as it the absolute worst choice as a horn loader.
Yes, a loudspeaker with a high EBP will give more "snap". The EPB for the 2220 series averages out to 200. Having an EPB that high residing in a properly calculated chamber volume coupled to a properly calculated throat area will indeed produce tight, articulate bass.
Someone on the forum some time ago posted a frequency response graph of the RLA / Jensen Imperial horn loaded with the 2225. Odd how many call that arrangement a "sub-woofer" considering the system begins to tank at 50 Hz. Although I have never heard one loaded with the 2225, I can imagine it must sound awful. The Jensen horn would be a viable design if the 2220 was used, and a recalculation of the chamber volume to couple properly with the fixed throat area. That being noted, a re-examination of the horn length would be in order, as the proper length of a rear loaded horn is based on the parameters of the relationship between the chamber volume and throat area.
One of these days I'll get around to recalculating the chamber volume of the Jensen horn based on a pair of 2220 drivers. It's unfortunate that no manufacturer on the planet makes a suitable horn loadable woofer that can out perform, or at the least, match the 2220. Believe me, I have looked. And I am still looking.
H.F.
Personally, I would go with the 2482 or the ALTEC equivalent driver, in conjunction with the 2405. Your choice of horn is up to you, but IMHO, I would avoid using a Constant Directivity horn.Quote:
Originally Posted by jpsweezey
Radials are best!
H.F.