5 cu-ft bass boxes for 2225H

[jbl]

Hi, Ron!

Plug one of the ports with 3" plumbers' test plugs and tell us what you hear, please....

Hi Zilch,
I tryed your suggestion and here's what I found:
First off, I attempted this as a listening test with various CDs. I didn't check WIN Isd before listening so that I would be open to what I was hearing.
The overall sound was about the same, except on a Bob James CD. There was a noticable dip at about 40 Hz. The result was a muddying effect. I didn't hear it on all CDs, but taking out he plug corrected it on that disc. I'll try more CDs over the weekend.

Ron

[4313B]

The result was a muddying effect.

Have Zilch check the group delay in BB6P. Stock and then with one port blocked.

[Earl K]

- This entire line of reasoning ( running a 2225H in a cabinet tuned below the speakers resonance and operated in a system alignment that is less than a "critical alignment ) is iffy at best .

- I'll admit it's a great way to magically turn the short coil 2225 into a long coil 2235 ( after you've had the recone kit installed ).

- I realize that in home HiFi it seems that almost anything goes but that doesn't make it right ( or best practise ). What's happened to using the right tool for the job ?

- I've used 24 , 2225Hs in system alignments that are critically damped while being tuned to 52 hz for over two decades. I've never burnt a coil or had one toss its' cookies and leave the gap ( & this is SR work ). These were all used without subs for a good 15 years. They do a fantastic job at creating fake bass when electronically enhanced ( LF boost ) & used in conjunction with a VLF high pass filter. Treat the 2225 right and it'll last forever. It's a great driver .

- The 4671 ( Cabaret ) had terrible unloading problems due to the system tuning being too low and the 2225H operating in an oversized enclosure. Yes, you can "derate" the input power for such practice / but in SR ? / & in real life ? / it just never happens & things just blowup .

- There are reasons to not tune these speakers below their Fs ( at least this & previous generations of JBL woofers ) . Perhaps the newer deep-gappers ( 1/2" deep ) can withstand this abuse better / I don't know since so far I haven't persued answering that specific question.

[4313B]

Perhaps the newer deep-gappers ( 1/2" deep ) can withstand this abuse better / I don't know since so far I haven't persued answering that specific question.

They can and do but...

In any case, nice post Earl. It looks like both you and Zilch appreciate the "right tool for the job" concept that I've been trying to convey since day one. There really is a reason why the 2225H is labeled a "2225H" and the 2235H is labeled a "2235H" and neither is labeled "all purpose woofer".

[Zilch]

Group delay of 2225H and 2235H in 5 cuft 4507 box per BB6P.

2225H:

Black = stock, 4 ports open, ~40 Hz tuning
Orange = 1 port closed, ~35 Hz
Red = 2 ports closed, ~28 Hz

2235H:

Green = 1 port closed, ~35 Hz
Blue = 2 ports closed, what I normally run here, ~28 Hz

[4313B]

Interesting Zilch... So he can hear that change in transient character eh?

[Zilch]

Interesting Zilch... So he can hear that change in transient character eh?

Seems pretty minor, no? And all well below the Blauert & Laws curve of group delay audibility.

In my experience, just about any change I make I'm gonna be hearing a difference in some instrument on some cut on one test CD or another. It may be a room or box resonance in this low range, as well.

Just part of the fun of playin' with tunings.

I'm with you and Earl here. As I said above, this ~35 Hz tuning is pushin' 2225H about as far as I can resonably conceive it playing well in this box. I do have some 2225H's here I could try myself to confirm....

[jbl]

- This entire line of reasoning ( running a 2225H in a cabinet tuned below the speakers resonance and operated in a system alignment that is less than a "critical alignment ) is iffy at best .

- I'll admit it's a great way to magically turn the short coil 2225 into a long coil 2235 ( after you've had the recone kit installed ).

- I realize that in home HiFi it seems that almost anything goes but that doesn't make it right ( or best practise ). What's happened to using the right tool for the job ?

- I've used 24 , 2225Hs in system alignments that are critically damped while being tuned to 52 hz for over two decades. I've never burnt a coil or had one toss its' cookies and leave the gap ( & this is SR work ). These were all used without subs for a good 15 years. They do a fantastic job at creating fake bass when electronically enhanced ( LF boost ) & used in conjunction with a VLF high pass filter. Treat the 2225 right and it'll last forever. It's a great driver .

- The 4671 ( Cabaret ) had terrible unloading problems due to the system tuning being too low and the 2225H operating in an oversized enclosure. Yes, you can "derate" the input power for such practice / but in SR ? / & in real life ? / it just never happens & things just blowup .

- There are reasons to not tune these speakers below their Fs ( at least this & previous generations of JBL woofers ) . Perhaps the newer deep-gappers ( 1/2" deep ) can withstand this abuse better / I don't know since so far I haven't persued answering that specific question.

Well said Earl. I'm VERY happy with the sound of the 4671 system. Been that way since 1985. Never felt the need for a sub. If I did, it would have been there a long time ago.

Ron

[jbl]

Well said Earl. I'm VERY happy with the sound of the 4671 system. Been that way since 1985. Never felt the need for a sub. If I did, it would have been there a long time ago.

Ron

Hi Zilch,
Try your 2225 vs 2235 and tell us your impressions. Also, try the 2225 with 1 port closed and see if you hear what I heard.
Thanks

[paragon]

This was an 4508 (8 cf) with two 2205A. Very good speaker. Response to 40 Hz in corner. Old pic, no data. Think 2225 in 5 cf is similar.

[jbl]

This was an 4508 (8 cf) with two 2205A. Very good speaker. Response to 40 Hz in corner. Old pic, no data. Think 2225 in 5 cf is similar.

Yes. The response is the same.