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Question for Wayne [message #36549] Mon, 20 May 2002 21:18 Go to next message
wasteh202 is currently offline  wasteh202
Messages: 137
Registered: May 2009
Master
Wayne is there any chance that substituting A JBL 2226 for the Eminence Delta 15 in the 4Pi Theater?

Will I give up to much sensitivity and will the crossover still be right?

Thanks in advance for your reply.

Theater four π vs. Professional four π [message #36551 is a reply to message #36549] Mon, 20 May 2002 22:10 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18700
Registered: January 2001
Illuminati (33rd Degree)

I wouldn't put a JBL 2226 in a Theater Series four π cabinet, because it's too large. The cabinet for a JBL 2226 should be no larger than roughly half the size of the Theater Series four π, unless you're doing something like an EBS, which is not the best application for a 2226. The model that uses the JBL 2226 is the Professonal Series four π loudspeaker.

The Theater Series four π Speaker goes deeper but has rising response in the bottom octave. Response is flat from (f3) 50Hz up, but has useful response to below 20Hz. It rises at 12dB/octave starting about 16Hz, so it can really go deep with room lift, and the slope is complementary.

Another characteristic of the Theater four π is the midwoofer's narrowing directivity making response rise 6dB in the octave just under crossover to the tweeter. When it is placed in a room corner, then the rest of the audio range is forced into approximately the same directivity pattern, and this equalizes response. Floor placement against a back wall comes close.

The JBL 2226 used in the Professional Series four π speaker does not have this kind of rising response. It has flat response on-axis, even through the region where DI begins to narrow. This is because the midwoofer has falling power response that is roughly equal to its rising DI.

The Professional Series four π speaker sounds more natural in large spaces. If it radiates into a constrained space, the bass will be a little over-emphasized. Tuning is slightly underdamped, so it doesn't sound boomy when used in smaller rooms or placed in corners, but it is best used used in larger environments radiating into quarter-space.

One more thing I should mention is the fact that the JBL 2226 uses a shorting ring. This dramatically reduces distortion, especially at midrange frequencies above 100Hz.

4 Pi Pro's are much smaller [message #36555 is a reply to message #36549] Tue, 21 May 2002 07:10 Go to previous messageGo to next message
Sam P. is currently offline  Sam P.
Messages: 307
Registered: May 2009
Grand Master
than the Theater series. You lose a bit of low end extension, but have lower distortion (numbers on paper, fwiw) from the 2226. Taut, articulate bass with individual notes well defined. And can run it with a simpler LP xover. The difference in enclosure size gives you about a 65 pound finished weight 4 Pi Pro, not sure how much the Theater series 4 Pi weighs, guys? Moving speakers DOES happen. I am personally really screwed if I ever buy another house :)

Seriously, the low end from the 2226's is fine, and IF I LIVED IN AN APARTMENT might be less obtrusive to the neighbors than a speaker going down even lower...maybe. For sure, the 4 Pi Pro's would fit into an "apartment sized" living space easier. If you need the bottom octave, you do need to consider the original Theater series design. Good luck, Sam

btw, if you are intending to use a 16 ohm 2226J...94dB/watt may be your result...it would be a great speaker still, but need more power to drive it well. and need considered when adapting the xover circuit.

Re: 4 Pi Pro's are much smaller [message #36556 is a reply to message #36555] Tue, 21 May 2002 09:35 Go to previous messageGo to next message
wasteh202 is currently offline  wasteh202
Messages: 137
Registered: May 2009
Master
Thanks for the repley both Wayne and Sam.

Actually I am looking for as much sensitivity as I can get, but my intention is to bi-amp and could stand to give up a little senstivity. I have access to a good deal on some new JBL2226 ($220.00 pair), and yes 16 ohm works well for me too! Size is not a key factor but I am looking for something as "musical" as I can get also would like to skip the sub and leave that out of the equation. Thanks for the info.

if biamp is the plan, go JBL! [message #36557 is a reply to message #36556] Tue, 21 May 2002 11:43 Go to previous message
Sam P. is currently offline  Sam P.
Messages: 307
Registered: May 2009
Grand Master
you can always add some low end EQ later. Maybe by the time you need them, Wayne will have active xovers available as KITS? Hint, hint,...Sam
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