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#222
BOB, the Big Open Baffle Project, is on track. The writing on the
first installment (one of several) is done, and I spent some time
last weekend tarting up the diagrams.

I plan to send it to AudioXpress, and of course they have a lead
time...

😎
 
#223
Any chance that any of these articles will be about a SOB ?(Small Open baffle) 🙂

p.s. Oh, no, that't too sad....better call it KOB (Klein Open Baffle) 😀

And..off topic question: Have you tried multiple 8" speakers (as bass helpers)on a baffle versus one 15"? Was it worth it?

Regards,

Vix
 
#224
The work has included comparative measurements of different sizes and
draw a few conclusions on the subject. The smallest width baffle I have
played with is 16".

And as to multiple 8", I have tried up to 20 per side. They all work fine.

😎
 
#227
fff0 said:
Hows the 16" baffle? Care to comment?
Click to expand...

On the plus side, the smaller baffles tend to have a spacious sound and work
well with smaller rooms. On the minus side, they work the woofer harder,
require a higher crossover frequency, and suffer more from the cancellation
which occurs when the back of the driver is one wavelength from the front
of the driver. This cancellation is alleviated a bit if you offset the driver, but
then you cut into the apparent width and you start thinking about some sort
of side panel.

We took a pair of baffles like this to RMAF in 2007 with PM6A's and pairs
of SEAS W26 woofers, biamped and equalized. They worked well, but if
you have the space, a little bigger is better.

One thing you can do if you are constricted on width is make them a little
higher. I find baffles with the FR near the top edge are problematic, so I
usually think in terms of driver height at 3 ft or so and top edge at 5 ft, and
this gives a little more bandwidth to the FR.

😎
 
#228
Nelson Pass said:
One thing you can do if you are constricted on width is make them a little
higher. I find baffles with the FR near the top edge are problematic, so I
usually think in terms of driver height at 3 ft or so and top edge at 5 ft, and
this gives a little more bandwidth to the FR.

😎
Click to expand...

Yes!
That's what I did. Additional baffle height works like a little extra width in regard to the response curve.
From my simulations for 8" drivers about 30-40cm above the *driver center* looks the best.
 
#229
Hi Nelson,

Thanks for sharing. 🙂
When you mentioned a little bigger is better, how big is a little bigger that you are referring to?

Whats the height of ur 16" baffle? If mine is the 5nf, wat will be the main things that I will need to look out?

For the pair of baffle at RMAF 07, can I know how did the guys managed on:
1) sensitivity difference? thru Active crossover or simply equalise it thru equaliser?
2) Time and phase alignment?
3) Are the woofers wired in parallel?

Above question can be reference to your system if you dont remember the RMAF configuration. Thanks in advance.

🙂
 
#230
Hi Nelson,

Thank you for sharing. In the end, everything comes to BiB. Bigger is better , baffle too. However, with some sorts of music I can't get full enjoyment through my 50 cm wide OB's...
Ideally, I should have two set of speakers:

1. OB's
2. Horns (BIB's)

In your analogy that would be like having both BOB's and Klein Horns...😀 😉 😎
 
#231
Vix said:
In the end, everything comes to BiB. Bigger is better , baffle too.
Click to expand...

Actually it's my experience that an OB can be too big. I spent
quite a bit of time with my 6' high x 4' wide baffles and concluded that
they were too big. Cutting them down to 5' X 4' was a real improvement.

I think at least part of that is due to the ability to access more of the
rear wave's "illumination" of the back wall and reduced standing waves
between the baffle and the wall.

😎
 
#232
Hey Nelson,
I had the pleasure of hearing your room at RMAF in '07 and I was really happy when I left your room. a real pleasure to listen to music in there, musical and chill . Again in '08, I was just loving your OB's but even better was meeting Colin and his generous expertise and sharing of info. Please thank him.
Do you plan to bring the Feastrex OB this year to RMAF? or maybe burning amp? Love to hear them...
 
#237
OK guys, Mr. Pass has well earned his success and I marvel at his products, but I have yet to hear a speaker with a whizzer cone, at any price, that sounds as good as a high quality dome properly matched to a good 6 or 8 inch driver. No that I have given up on full range, at age 73, I am still experimenting, seeking that grail of single driver sound. Mr. Pass let us know your results with the new drivers.
 
#239
Hi Nelson,

Wonder if you are still favoring open baffles.

I have a couple of questions.

1) Did you consider / experiment with different baffle materials ?

I got a good result with a laminate of 1/2" MDF bonded with PVA to 3/4" concrete. This was my best baffle to date but I think 10mm Aluminum bonded to MDF or birch ply would also be a very good candidate. Bonding two dissimilar material seems to substantially cancel each of their resonances.

2) All OB speakers I have seen have the speaker placed centrally on the baffle but when experimenting with "edge" software it seems to me that the best arrangement is having the driver close to one edge and then adjusted vertically for the most linear response. But no one seems to do this - did I miss something ?

cheers

mike
 
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