4412a new cabinets

[foxx510]

Hi all, there seems to be some serious JBL knowledge here, hopefully someone has some thoughts on my project. I have a set of 4412a monitors, which I like apart from one thing, they don't throw a big image and the image moves too much with tiny head movements. I would like to design some new cabnets with a vertical configuration rather than the horizontal arrangement they have now. I have two possible ideas at the moment, the first is just a classic upright box alignment with the drivers close to the center but slightly offset, or seperate small enclosures for the mids and highs to reduce any baffle interactions. My main concern is that the crossover values will be wrong once I take the drivers from the box they are in now. I think that new heavier, braced MDF enclosures will make the bottom end much better also, I think the current cabs are pretty cheap and nasty. Any suggestions are appreciated.

Thanks
Adam

[Zilch]

My main concern is that the crossover values will be wrong once I take the drivers from the box they are in now.Maybe. Just do it and fix that later.

L100 T3 configuration floorstanders:

http://manuals.harman.com/JBL/HOM/Technical%20Sheet/L100t3%20ts.pdf

Giskard's Mini L250s:

http://audioheritage.org/vbulletin/showpost.php?p=147642&postcount=18

Zilch's trapezoidal Z2, scaled down:

http://audioheritage.org/vbulletin/showthread.php?p=61967#post61967

[foxx510]

Thanks for the quick reply! I'll check out those links. My worry is that I don't have the experience or measuring equipment to make xover mods if they are needed. I might try the budget option first, leave the LF drivers in the current cab, seal the holes, and make some small enclosures for the mid/highs and see if the idea has any potential with the stock xover.

[BMWCCA]

Have you tried setting them upright on the floor? I found they work best when vertical if they're raised slightly off the floor. Depending on your room dimensions and placement, you might experiment swapping them R to L to find the optimum HF placement for your listening position. Do you have them horizontal at ear level now? How far apart? HFs in the center? Have you swapped them L/R in the horizontal orientation?

[foxx510]

They are currently set up, 1m or so apart with the hf on the outside and around 1.5m from the listening position at ear level. If you stick your head in there in the right place there is a decent image, but I find it is not a relaxing way to listen to them. I was inspired to change them when I heard the image created by a friends NS1000s, there was music a good 1.5m each side of his speakers, something I have never had with these, and the image didn't fall apart if you moved your head, this is what really bugs me at the moment. I also feel I can hear a cabinet resonance around 150-250hz which could be fixed with a decent cabinet. I heard a little set of Sonus Faber bookshelf speakers yesterday, and while they didn't have the punch and spl capabilities, they absolutely creamed the 4412s for imaging and not sounding like speakers, there was just music there. This is what I want! I will try then vertically in the current cabs today again but I'm sure in the past I could never get them right in this config due to the mf and hf being on the same plane.

Thanks
Adam

[Zilch]

Look closely at the spec sheet. They behave differently in polar response up versus down oriented horizontally.

I agree regarding imaging, and have always considered the driver cluster layout "suspect."

[foxx510]

I couldn't find any polar response information, do you have a link? I think this quote from the advertising says a lot though "this 3-way system tightly
cluster its transducer complement for accurate close proximity listening" . I think it would be safe to say a new cabinet and driver layout would make a significant difference. I would like to get away from using a sharp edged baffle too. Fingers crossed that the response stays flat!

[Zilch]

Well, you've got to go back to the original 4412 to see it. I believe it was RobH that first pointed this out. Look closely at the Vertical Off-axis Response Curves for the differences resultant from driver placement in the cluster:

http://www.jblpro.com/pub/obsolete/4412.pdf

[foxx510]

Thanks for that. To be honest I had a hard time interpreting the real world effects of that polar response graph, I still have a lot to learn here. If you have time, a semi-laymans explanation would be much appreciated! If you were doing what I was doing, what sort of cabinet would you be building?
Thanks for you help.
Adam