Help with fomo - JBL 4645C Subwoofer

[smygolf]

What is the acceptable group delay?

And a big thanks to you…. Here are your freshly prepared cookies XD
View attachment 493211

Cookies ?!
Do you think i am a brute

 

[sahil fardeen]

Cookies ?!
Do you think i am a brute

xD

In the 4645 cab, apart from the distortion advantage, there isn’t much output gain with the 2269, port velocity being the bottleneck

 

[smygolf]

xD

In the 4645 cab, apart from the distortion advantage, there isn’t much output gain with the 2269, port velocity being the bottleneck

2269/18N862 can take much more power and has double the stroke
That will also increase air velocity when you push beyond what 2242 can take.
But the design still holds up, might be at extrem lvl at 20hz there can be some chuffing.

 

[sahil fardeen]

2269/18N862 can take much more power and has double the stroke
That will also increase air velocity when you push beyond what 2242 can take.
But the design still holds up, might be at extrem lvl at 20hz there can be some chuffing.

White is 2269, blue is 2242

Transfer Function magnitude:

SPL:

 

[sahil fardeen]

White is 2269, blue is 2242

Transfer Function magnitude:
View attachment 493529

SPL:
View attachment 493530

Transfer function coincides with which JBL published. A 6db higher output at 30hz for the same input.

Why in the spl tab the 2242 outperforms? any idea?

600w at 2m is the reading

 

[sahil fardeen]

2269/18N862 can take much more power and has double the stroke
That will also increase air velocity when you push beyond what 2242 can take.
But the design still holds up, might be at extrem lvl at 20hz there can be some chuffing.

Is there anyway i can pump in >1000w and still stay under 20m/s air velocity?

Even at 1600w, the 2269H still have room left and is under its limits :O
Also,
xti 4002 can do 2400W @bridged 8 Ohms

 

[smygolf]

2242 has higher overall sensitivity but looses a lot down under 45hz

 

[smygolf]

Is there anyway i can pump in >1000w and still stay under 20m/s air velocity?

xti 4002 can do 2400W @bridged 8 Ohms

2269 wattage yes but nothing i would do continius.
Air speed correlates to port widht - bigger port = longer port and higher group delay.

 

[sahil fardeen]

2242 has higher overall sensitivity but looses a lot down under 45hz

iirc 2269 dominates below 80hz which is the same freq range that matters to us.

The lower sensitivity quote for 2269 was it doesn’t output nearly much above 80hz till 500hz as the 2242

 

[sahil fardeen]

2269 wattage yes but nothing i would do continius.
Air speed correlates to port widht - bigger port = longer port and higher group delay.

So in short, the extra wattage and xmax is of no use, unless dealt with gigantic and abnormal enclosures as big as a mini truck…. OR going sealed which looks counter intuitive xD

As you said - bigger port- bigger group delay, so this also limits

 

[smygolf]

So in short, the extra wattage and xmax is of no use, unless dealt with gigantic and abnormal enclosures as big as a mini truck…. OR going sealed which looks counter intuitive xD

As you said - bigger port- bigger group delay, so this also limits

Correct.

But gains in lower distortion and you can play louder with 2269
2242 in blue, the jagged edge is a bad thing, it hits several limitations
2269 are far from hitting mechanial limits, it only hits max wattage.
This is the only reason i never did the swap, also distortion is really hard to hear so far down.

 

[sahil fardeen]

Correct.

But gains in lower distortion and you can play louder with 2269
2242 in blue, the jagged edge is a bad thing, it hits several limitations
2269 are far from hitting mechanial limits, it only hits max wattage.
This is the only reason i never did the swap, also distortion is really hard to hear so far down.


View attachment 493536

Also worth checking out:

Data-Bass: Subwoofer Measurements

data-bass.com

(Should roughly indicate the 2269 performance)

This is some serious performance, but also worth noting the input power given to this was in excess of 2500w

 

[g_t_r]

I still can't get any meaningful bass from my 2x 4645c I have connected them via chinch cable from pre (levinson 320s) to Crown XLS202, input sensitivity in crown set to high / volume on crown set to MAX. My front hi-fi speakers can still generate stronger / deeper bass, during normal daily listening levels drivers are barely moving (actually I can only feel vibrations when I'm touching drivers). Is this setup issue? I would expect that even single 18inch driver with 2400W bridged power will teleport me to the moon in small apartment room whereas I have troubles to even guess / hear if I turned on my subwoofers... hmmmm :/ Underpower? FAKE Watts from crown amp?

 

[smygolf]

I still can't get any meaningful bass from my 2x 4645c I have connected them via chinch cable from pre (levinson 320s) to Crown XLS202, input sensitivity in crown set to high / volume on crown set to MAX. My front hi-fi speakers can still generate stronger / deeper bass, during normal daily listening levels drivers are barely moving (actually I can only feel vibrations when I'm touching drivers). Is this setup issue? I would expect that even single 18inch driver with 2400W bridged power will teleport me to the moon in small apartment room whereas I have troubles to even guess / hear if I turned on my subwoofers... hmmmm :/ Underpower? FAKE Watts from crown amp?

How many LED in the crown are lite while playing ?

 

[Puddingbuks]

I still can't get any meaningful bass from my 2x 4645c I have connected them via chinch cable from pre (levinson 320s) to Crown XLS202, input sensitivity in crown set to high / volume on crown set to MAX. My front hi-fi speakers can still generate stronger / deeper bass, during normal daily listening levels drivers are barely moving (actually I can only feel vibrations when I'm touching drivers). Is this setup issue? I would expect that even single 18inch driver with 2400W bridged power will teleport me to the moon in small apartment room whereas I have troubles to even guess / hear if I turned on my subwoofers... hmmmm :/ Underpower? FAKE Watts from crown amp?

Does one JBL play loud? Can't they both play loud? Have you switched the amp and source? Did you try to set the input sensitivity to low?

Please post everything you tried so we don’t have to read 25 pages.

 

[pauldavidthomas]

I still can't get any meaningful bass from my 2x 4645c I have connected them via chinch cable from pre (levinson 320s) to Crown XLS202, input sensitivity in crown set to high / volume on crown set to MAX. My front hi-fi speakers can still generate stronger / deeper bass, during normal daily listening levels drivers are barely moving (actually I can only feel vibrations when I'm touching drivers). Is this setup issue? I would expect that even single 18inch driver with 2400W bridged power will teleport me to the moon in small apartment room whereas I have troubles to even guess / hear if I turned on my subwoofers... hmmmm :/ Underpower? FAKE Watts from crown amp?

I tried using Crown XLS's in bridge mode - no base. Used I think the XTI with a PROFILE for these sub and sounded great. Use the correct amp.

 

[g_t_r]

How many LED in the crown are lite while playing ?

All LEDs seem to blink normally (full signal).

 

[g_t_r]

I tried using Crown XLS's in bridge mode - no base. Used I think the XTI with a PROFILE for these sub and sounded great. Use the correct amp.

So your theory is simply wrong amp? I'm wondering what is wrong with this crown that is unable to drive high efficiency 18 driver. It should be loud as hell...

 

[smygolf]

And xlx202, is it bridged and subs in parallel ?
4645C do not like to be pushed beyond 600-700W so above config should work.

But (!) they are made to be in baffle wall, not standing against a wall or corner - true half space.
Without it do not cont with much output below 30hz - but with 2 and enough power you should be able to reach +110dB @ 1met

Do a nearfield measurement and then at mlp, could be that the room modes just kills all the bass

 

[Speaker-Inquisitor]

Is there any Signal Processing active in the crown amps? Afaik they have a dsp, so Maybe a highpass is active?