329A or 311-90
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with grille cloths(marshall bluesbreaker gray)
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I’m witholding judgement until the system gets moved to its new home later this year but:
-it sounds great
-i wonder what larger altec sectoral horn would get me safely down to 300hz...
Last edited by Steve Mac; April 4th, 2021 at 12:15 PM.
329A or 311-90
Your neighbors called. They like your music.
Thanks, will these horns properly couple the 288 down to 350hz?Originally Posted by Old Guy
Would I still need to consider a higher filter than 12db?
Didn?t you have a pair of the 311-90s?
It depends on the max power it will likely 'feel' since these horns at a ~220 Hz cutoff are way too short for true 300 Hz loading and barely long enough for their 500 Hz measured ratings [1 WL effective path-length]. Ditto 300 Hz multi-cells.
In short, the 300 Hz rating is about pattern control [polar response] over a wider bandwidth [BW] to a lower frequency [Fc].
Edit: My [failing] memory caught me out.Went back and pieced together the [assembled] dims and all the [3] suffix multi-cell horns have sufficiently long path-lengths for the claimed 300 Hz rating.
Last edited by GM; April 9th, 2021 at 12:41 AM.
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Spot on that you will lose some pattern control. 24 Db/octave helps. The octave down is 150 Hz, should be around 12 Db down at 220.
Your neighbors called. They like your music.
Another option is the one I PM'd awhile back, i.e. a horn baffle large enough to support 300 Hz that combined with reduced power should suffice.
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
thanks gm...
How high the moon...err how big the baffle.
I would be okay baffling left and right to the edge of this design but how high above the 511e?
...depends on the xo freq and the xo slope and how hard it’s driven...in general not a fan of steep xo points but willing to try
Last edited by Steve Mac; April 6th, 2021 at 12:38 AM.
OK, how wide is the mids box?
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
outside dimension width = 36”(3 ft)
Well, we're basically dealing with a 1 WL of 300 Hz/4 = 75 Hz = ~58" dia. wave, so ~29" from the horn centerline down will drape over the mids and part of the subs, so ideally need to square them up and use closed cell foam insulation or similar to seal the joints, then a 36" w x 36" rounded up and seal the horn/baffle joint.
This might be sufficient, but it's now going to reinforce some part of the sub's, mid's output, so it ideally needs to be well braced, recommending 'boxing' the horn in [open back] to the depth of the mids cab and placing concrete bricks or similar on the bottom plate to mass load it. Better still, Velcro one or two to the horn.
Reinforce the back perimeter, toss in enough damping to mute any hollow sound and the sum total will for sure load to < 75 Hz, which would need to be measured, but a basic pipe end correction would be ~29" x 0.613 = ~17.8"+ ~181 = ~198.8" = ~13543/198.8 = ~68 Hz, so pretty confident it will load at least this low as the sides of the mid/tweet cab will contribute some also even though at 90 deg.
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
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