JBL Master Reference Monitor

[Robh3606]

Hello 4313B

Should be fun! Can't wait to see how they measure up compared to the PTH1010. I am very curious about them.

Rob

[Flaesh]

http://reconingspeakers.com/product/
...
$1,139


I'd say that opens up all kinds of world class DIY project possibilities. Unprecedented!

M2 grill assembly, crossover and horn logo also listed there.
This will add $294 .
D2 aren't in stock .

[Ed Zeppeli]

Crossover?

[Flaesh]

yes . not quite accurate name for 2 resistors and 2 parallel protection caps. not cheap: http://reconingspeakers.com/product/...sover-5030032/

[4313B]

We have the schematic for the crossover so there is no reason not to build a charge-coupled version for our DIY projects. There is no way I would use that stock network with this caliber of a system.

[pos]

That is a protection network for the D2 (fixed lpad and cap).

The network is in the technical manual, and it is easy to replicate with higher quality parts for a lower cost...

I think I have four 75uF solen caps laying somewhere, and also some 9V battery connectors

[pos]

mad minds think alike

Have you noticed the price increase on the horn?
It was $250, then $260, and now $299...

[srm51555]

Has anyone completed their waveguide/2216nd with favorite 1.5" driver system yet, or are we all waiting for the waveguides? Last time I called they were two weeks out and they only had 7 sets coming in. I was order #6. I also wouldn't mind picking up some ports if they were available reasonably.

[pos]

I also wouldn't mind picking up some ports if they were available reasonably.

These are not available as parts.
Looking at the pictures it looks like the port has an inner diameter of around 90mm.
I found a 70mm and 100mm adjustable 3-parts port that could fit (using the internal flare on both sides to avoid visible screws).

It would be nice to get measurements from someone that has the M2 at hand...

[Valentin]

Here are some pics of the ports





it is about 8" deep and it is irregular
the diameter gets smaller further in than center and then opens up again

[Aaron]

This probably doesn't need saying, but if you made the front baffle properly thick (1.5" or so) you could give the front a huge 1" round over and still have room to rout a step in the back to snugly fit a PVC pipe. Don't forget to garnish the inside end with some small plates using the same technique.

I hope I'm making sense. If not please say so & I'll post a pic of what I'm on about.

[4313B]

Bass box sims in the room with 27 Hz tuning put it in the low 20's.

That not bad for 135 litres

How about the Bass Box closed box sim with a linkwitz transform applied? Just tossing that out here for the sake of science.

Type: Closed Box

Vb = 2.039 cu.ft
Qtc = 0.707
QL = 18.2
F3 = 32.73 Hz
Fill = normal

I was looking at my two 2206H boxes (2 cu ft) and thinking about how nice the size was. Then it occurred to me that I could stuff 2216Nd's in instead, apply the transform and viola! ~ 30 Hz instead of ~ 60 Hz

[ivica]

These are not available as parts.
Looking at the pictures it looks like the port has an inner diameter of around 90mm.
I found a 70mm and 100mm adjustable 3-parts port that could fit (using the internal flare on both sides to avoid visible screws).

It would be nice to get measurements from someone that has the M2 at hand...

Hi POS,
Ma be interesting study of : Maximizing Performance from Loudspeaker Ports

http://koti.mbnet.fi/jahonen/Audio/P..._PortPaper.pdf

regards
ivica

[4313B]

Thanks for that link Ivica!

[pos]

Here are some pics of the ports

it is about 8" deep and it is irregular
the diameter gets smaller further in than center and then opens up again

Thank you Valentin!
Is there a tubular part in the middle, or is the profile constantly changing?
Could you measure the smallest diameter inside the tube?

I think a 70mm tube with large inner and outer flares needs to be around 8" to get a 27Hz tunings in a 140L box.