[miguel42]

has anybody tried any alternative baffle designs other than a flat/curved panel or h-frame.
on a asthetical note both of the above work well but are a bit ''in your face'' especially with her in doors.
will the ob design work turned through 90 deg(bass units only),or maybe add some kind of deflecting surface either side to help push the sound forward and back!!
the 90 deg option works for reflex designs, any thoughts on ob units
any thoughts anybody

[Telstar]

Look at the Gradient Helsinki.

[panomaniac]

On open baffle there is a deep null at 90  degrees.   Point that null toward you, and you won't get much direct sound.
The reflected sound will be much louder.

So mostly the sound will not be going where you want it.

[ultrachrome]

You can apparently point that null toward a corner to good effect.  The gradient helsinki works with that approach.  Think it's called a corner bisector.

[ultrachrome]

Here's an example...

[Rudolf]

Stacked ripoles with an AER driver in transparent waveguide:

 

More at http://www.audiocircle-rl.dyndns.org/produkte/ls/standls/bmc200.html

[miguel42]

i have already discovered about the 45% placement arrangement,experimenting at home (once i get started on a project that's it) and it works really well,also aesthetically it makes for an overall smaller 'enclosure' dimension which also keeps the wife happy, but what more could i want you ask!!!
bass extension,i am only using a single volt 3143 driver on each channel but it gives excellant flat response above 40Hz, at the same time giving a db reading only a little higher than the mid & treble.(perfect)
it can only be lack of lower extension!!
the main reason with sticking with the volt driver is the high? qts (giving exceptional punch & control not forgetting the radial patent & build quality,i know this goes against the grain when it comes to qts selection and ob design but from what i am hearing high qts gives a much slower/muddy bass(and this seems to be the real challenge,i cant find any other ob designers in England,not even jamo r909's are available at any dealers).i think the only thing is to use are the H enclosure design (thanks for the 1/4 wave link) and double up on the drivers,looks like i will need to get to the bank statement before the wife though...will keep you infomed..mike

[miguel42]

i forgot to ask,any idea on what those bass drivers are in the gradient helsinki units (nice looking!) the baskets look like AE UNITS,any idea's ?

[Rudolf]

any idea on what those bass drivers are in the gradient helsinki units (nice looking!)

They are exactly built like the Peerless SLS drivers:
http://blog.stereophile.com/rmaf2008/gradient_helsinki/

[ttan98]

any idea on what those bass drivers are in the gradient helsinki units (nice looking!)

They are exactly built like the Peerless SLS drivers:
http://blog.stereophile.com/rmaf2008/gradient_helsinki/

For side firing woofer, the x-over freq, must be less than 140Hz.

[Rudolf]

For side firing woofer, the x-over freq, must be less than 140Hz.

I guess you took that value from monopoles with side firing woofers, where the midrange driver is in front of the woofer. The midrange driver of the Helsinki is not in front of the bass driver, but almost exactly above it. So I don´t see how that rule should apply.