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Close, though its height, width horn dims are a little different for whatever reason, its area expansion is the same as a truncated 210 that relies on a hard floor's mirror image to increase its final expansion.Quote:
Originally Posted by valhallax
GM
so what output and sensitivity would I get with a half 815 with one 515-8G then?
I guess the freq would be unchanged?
mean to cross @75 to the BD towers and 5-800 hz for wood 1505s with 288c or someting
best
Leif
Quote:
Originally Posted by leifchristensen
Quote:
Originally Posted by leifchristensen
Of course, same as for the 210, i.e. F3 rises a half octave, or viewed another way; a single driver in a half size 210 laying down on the floor (2pi space) in theory has the same gain BW as a 210 suspended in 4pi space.
Use your imagination. ;)
For instance, I chopped the horns out of a pair of 210s, 'skinned'/braced them at 90 deg and added a ~triangular shaped sealed rear chamber so I could shove them into the room's corners.
WRT rear chamber net Vb, it's dependent on driver specs and desired F3/roll-off slope which in turn is room gain curve dependent, so typically folks make too big a chamber and experiment with reducing it to suit, or in the case of compression loading, reducing it until its tuning matches the horn's which requires measuring its impedance.
Bottom line, if building from scratch it's well worth the extra effort to get rid of the 210's, etc. parallel horn walls that I never could satisfactorially damp without affecting its response too much.
Anyway, I initially helped Steve Mac with his reshaped, sealed rear chamber 210s and from there he used his math skills to program an Excel calculator and worked out cut angles, etc., so maybe he can be 'sweet talked' into doing the math for you. BD could too for that matter, so maybe you can get a bit of added value from your purchase.
GM
ok I see
hmmm
best
Leif
The literature says the 815 is a "truncated" version of the horn portion of a 210.
GM
can I calculate all the horn flare areas at the 4inch lines in the drawings
redo it for square horn and do the backwords math ?
then I?d get the right flare rate I think
that should be fairly easy to make in an Excel spreadsheet
or where do I get hold of Steve Mac?
best
Leif
Yes, you can do that or input the throat, mouth area and axial length into HornResp and it will calculate the horn, then you can export/print out all its design data.
He's here, but apparently not following the forum much these days: Hostboard - View Profile: Steve Mac
GM
Interesting, don't recall ever seeing them admit it in print. Is it available on-line?Quote:
Originally Posted by Old Guy
TIA,
GM
I made an Excel sheet that gave me this:
best
Leif