DIY-project: JBL Kebnekaise S4365

[bubbleboy76]

Btw did your 045be arrive safely?

Yes they arrived safely, and they look much better than the pictures looked like.
I hope distortion-measurement looks nice as well later on....

[johanwholst]

Im glad to hear that! It was a sweet deal

[bubbleboy76]

Yes!

[bubbleboy76]

Oh yes.

[bubbleboy76]

Quote from my friend:
Why do not JBL make them like this? They would sell thousands!

So JBL, feel free to contact me if you want to sell thousands of this model. Just give the contributors this thread a set of nice top-shelf drivers, and you are good to go

[Odd]

Quote from my friend:
Why do not JBL make them like this? They would sell thousands!

So JBL, feel free to contact me if you want to sell thousands of this model. Just give the contributors this thread a set of nice top-shelf drivers, and you are good to go

I would think JBL is waiting for your measurements before they contact.
We others are waiting too.

Very well done project.

[bubbleboy76]

I would think JBL is waiting for your measurements before they contact.
We others are waiting too.

Very well done project.

Yeah now the fun begins. I am not so interested in the hardware actually, more the software. But I had to put a year on hardware first, as it turned out.

[pos]

Looking good

[bubbleboy76]

Quick-and-dirty measurements of the woofer boxes.

No EQ filters. 1/24 smoothing.

The speakers not fully inserted in the corner yet, and without the damping I will have later between speakers and wall.

I see that the dual vertical woofers seems to nicely cancel out a lot of each-other's SBIR (from floor and roof mainly, I guess) .

I also see that my room front corners do not behave the same acoustically (different kind of walls). Larger "corner-problems" on Left speaker. That corner is concrete walls. The other corner is wood/plaster. I maybe will have to make separate EQ-settings per speaker. Or maybe it is good with different LF behaviour from L and R down low, to smooth things out in total?

(Note, the dB-level was not calibrated in REW. It was higher than shown in the graphs.)

[hlaari]

Great to see at you finish your project
the enclosure are very well made





Ari

[bubbleboy76]

Small steps ahead. Cloth on the grilles.
I will add another layer, so the woofers are not shining through. I will try to find a better color-matched white cloth.
It's all white because I want the speakers to blend in with the walls (for them to disappear as much as possible).

[bubbleboy76]

Damping/support between speaker and wall.

The speaker will now be pushed in as deep as possible into the corner. This will push the SBIR cancellations from the walls behind the speaker up in frequency. Hopefully up into an range where the speaker is more directive, and where resistive damping has more effect.

(In a future dedicated room, the cabinet shape enables me to dock 12cm resistive damping to the sides, to reduce the harmful side-wall early reflections. Current room and current wife does not enable this though!)

Next step: a lot of measurements.

[bubbleboy76]

Another thing, it has started to sound pretty good as well! I really believe this stuff has quite some burn-in time, especially for me that can not play so loud in an apartment.

[bubbleboy76]

One of the JBL 045Be drivers I bought on ebay is bad.
See comparison with the good one. Measured from 10cm, with 3 cycles frequency dependent window.
Big suckout 4000Hz-7500Hz.
I had them cleaned magnet gap and cleaned membrane and installed properly centered in the horn with the correct screws by a speaker repair-firm. But still same problem.
Don't know if it matters for use 10KHz-20KHz though?

Anyone having a single 045Be to sell?

[ivica]

One of the JBL 045Be drivers I bought on ebay is bad.
See comparison with the good one. Measured from 10cm, with 3 cycles frequency dependent window.
Big suckout 4000Hz-7500Hz.
I had them cleaned magnet gap and cleaned membrane and installed properly centered in the horn with the correct screws by a speaker repair-firm. But still same problem.
Don't know if it matters for use 10KHz-20KHz though?

Anyone having a single 045Be to sell?

Hi bubbleboy76,

Did You check phase plug proper gluing , as I have seen on some JBL older drivers 2447, and 2451, that central part of phase plug can be moved due to the bad glue used.
Another experiment can be made, some paper 'shims' put under the diaphragm mounting ring in order to make some distances between the diahragm and the phase plug (just for an experiment).
Check with lower frequency tone of a kind of a buzzing noise can be hear due to mechanical diaphragm&VC assembly touching with the driver&phase-plug assembly.
Is there any diaphragm 'fracture' or VC bad gluing to the diaphragm.

I wish You to overcome the problem.

regards
ivica