[JohnR]

Hi Rudolf - I think Edge is normalizing to mic distance. So there is not actually a need to change the mic distance, just the horizontal distance (scaled accordingly).

In either case, it looks like the level will need to be adjusted as you move off-axis e.g. at 45 degrees, by 3 dB.

That's what I think I'm seeing when I try this anyway.

[Rudolf]

Hi Rudolf - I think Edge is normalizing to mic distance. So there is not actually a need to change the mic distance, just the horizontal distance (scaled accordingly).

In either case, it looks like the level will need to be adjusted as you move off-axis e.g. at 45 degrees, by 3 dB.

Hi John,
as I understand it, Edge will normalize all open baffles to +6 dB for high frequencies (and 0°) - regardless of mic distance. But the shape of the response will vary with distance, admittedly more for small distances than long ones.
For more than 15° all off axis values will be plainly wrong. Adding 3 dB at 45° is the right direction, but still not the truth. Nowadays I use Edge only for very rough estimations, if going off axis.

Rudolf

[Ric Schultz]

Regarding Alphas up to 1K.....if you are using one of the stock drivers on a poor baffle with no bracing you will be very disappointed with their upper end performance....actually, they suck terribly in the bass used that way too.

Here are the ways to make a seriously great sound:

1. Run two in parallel.  This lets them move half as much and therefore less coloration/distortion.
2. Put felt on the inside of the basket struts to keep the higher frequencies from being reflected back into the cone.
3. Damp the outside of the frame with EAR SD40AL.  This constained layer material is the best I have heard and this will make the speaker sound way better at all frequencies.  I doubt bituminous felt or other damping material sounds as good.
4. The baffle must be at least 2.25 inches thick using 3 layers of highly refined MDF (Rangerboard, Medite 3D) using green glue in between each layer.  This will be a seriously dead baffle.  Way better sound.  Of course, you can also use bamboo plywood or other great wood in layers using green glue in between.
5. Brace the baffle with a huge brace that also is attached to the magnets of both woofers and is solidly attached directly to the baffle and to the base.  This is mind blowing and an absolute must.
6. Hook up the woofers directly to the amp....do not use binding posts, spades or the like.  Simply hardwire some PCOCC wire between the drivers and hardwire your speaker wire to one of the woofs....solder them directly.

You do the above 6 things and use a highly modified Behringer DCX24/96 crossed at 1K and you will swear you are listening to an electrostat!  Of course you could get even more articulation by using smaller drivers between 100 and 1K......but if you think you are getting bad sound from an Alpha 15 it is because you have not done the above 6 things.....ALL of them must be done for truly great sound.

If you check out my gallery you will see a pic of a speaker done this way.  The brace is very funky that my friend did but even so he says the improvement the brace made is comparable to the last $10,000 worth of other upgrades in his system.  Cost him $50 for the wood, glue and hardware.  He is running two Alphas to 900 and crossing to a Beyma compression driver mounted in a Geddes waveguide using highly modded Behringer.  Incredible speakers!!!