Sadly, this is the most technical info. I was able to dig up. I was not able to find the pending patent docs...
https://www.youtube.com/watch?v=sIc2ORiDxrE
Sadly, this is the most technical info. I was able to dig up. I was not able to find the pending patent docs...
https://www.youtube.com/watch?v=sIc2ORiDxrE
Thanks for the responses.
Since this is a proprietary design for JBL, they won't sell the ports either. No matter, it is still a venturi, and can be easily copied by enterprising DIY people.
All we need is for someone to take a snap-gauge and caliper and measure the smallest part of the port, and the o.d. of the inner port bell and we can do the rest.
Valentin has already kindly measured the length, which more or less coincide to the data on the M2 tech sheet provided by 4313b.
Or buy whatever flared ports you like and tune to length appropriately
Method for predicting
Loudspeaker port performance and
optimizing loudspeaker port
designs utilizing bi-directional
fluid flow principles
AES_PortPaper:
http://koti.kapsi.fi/jahonen/Audio/P..._PortPaper.pdf
___________
Peter
Well the M2 HF protection network comes with a small surprise.
ATTACH]68669[/ATTACH]
The cap values are 3.3µF and 4.7µF.
If we knew what the hell we were doing, we wouldn't call it research would we.
Maybe he'll turn up with some of those ports next
Who is this masked Audiohack maniac!!
Nice job!!
Always fun learning more.......
Hi All;
I thought that since JBL did such a bang-up job with the M2 that to start out at least I should start with this little network in just to be sure I had the top end right.
I am going to depart from the design with a 4435 type cabinet and four 2216's. I just like the form and two 15's close coupled gives me the sound I love. I have one but still have to buy two more I-Tech 5000Hd's, ouch! At first I will likely just run the woofers on a DBX260 and a pair of non DSP amps.
I ran the drivers on the PWT and they are pretty well matched and have consecutive serial numbers, two nice surprises. The top curves are direct drive and the lower two are with the M2 network in series. The network pads the driver down 9.2dB from 3kHz on up and is down 12 dB by 250Hz.
I can't wait for Christmas break to build cabinets!
If we knew what the hell we were doing, we wouldn't call it research would we.
If we get some complete geometry on the ports, since they are flat panel mounted we could make those easily from aluminum bar.
The Everest port and terminal panel? That one is going to be a challenge.
Barry.
If we knew what the hell we were doing, we wouldn't call it research would we.
Study the circuit
____________
Peter
Something on this page should get the port issue sorted
https://www.google.co.uk/search?q=Fl...w=1024&bih=650
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