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Old 10th June 2013, 08:06 PM   #111
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Yeah, that is a significant consideration to make before making a corner horn such as this, I suppose. Well, sadly my new amp is in the shop and I can't get a proper test made of this speaker for at least a week. Until then, no measurements and no music.
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Old 12th June 2013, 07:03 PM   #112
DrBoar is offline DrBoar  Sweden
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Here are the hand plotted graph I made in the 80s! The test tone is warbled by a 8 Hz sinus tone so 50 Hz really is 42-58 Hz. It appears that the losses start below 100 Hz and then give -4 to - 6 dB down to the 40 Hz drop off of the horn itself.

To what extend this apply to MJKs BLH and how much improvement is to be had by having double plaster walls or shorter stud distances is anyones guess. But I have experience in other plaster walls and just doubling the plaster to 2x 12mm gave a far sturdier wall.

Click the image to open in full size.
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Old 12th June 2013, 07:31 PM   #113
chrisb is online now chrisb  Canada
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DrBoar - if I might suggest that use of the term "plaster" might be a bit misleading, as the density of the material itself, and backing substrates would be quite different from the now far more commonly used "gyproc" / "drywall" board.

Not all drywall materials, even of the same thickness are created equal, and within the past few years new formulations have been developed with sound deadening qualities.

But you're certainly right in that 2 layers of 1/2" or even 5/8" standard drywall on 16" centered 2x6" wooden studs will provide a much more rigid surface than single layer on 24" centered lightweight metal studding that is more commonly found in none load bearing walls than you might be aware of. Just ask an installer of wall mounted upper cabinets in commercial office spaces.
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Old 12th June 2013, 08:41 PM   #114
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This is interesting. I am corresponding with another European who was mentioning 6mm plasterboard. Is this a common construction practice? I believe that my 35yr old house has 1/2" drywall on 16" center 2x4's. I think that this is still standard practice. 5/8" drywall is also commonly available.

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Old 12th June 2013, 10:42 PM   #115
Ivo is offline Ivo  Netherlands
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Here in Holland, plasterboard is rarely used for walls. It's mostly brick and concrete for outer walls and "gass cell concrete" or solid gypsum blocks for interior walls. Old houses have wooden floors, after about 1975 it's almost all concrete. Plasterboard is usually used for false ceilings, or quick and cheap remodelling.

When we see footage of an American town that's been destroyed by a hurricane, we always wonder why they build their houses in such a fragile way. Perhaps the reason is cost, easier to rebuild after such extreme natural violence. I have to admit that I'm not sure our concrete and brick houses would hold up much better.

But anyway, lots of concrete here and so lots of roomgain.
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Old 12th June 2013, 10:45 PM   #116
Ivo is offline Ivo  Netherlands
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I don't have a good pair of corners, unfortunately. I'm running a 2.1 FAST setup with a sealed sub now and am considering building a monster of a cornerhorn to go replace that sub. Sort of the last sub I am going to make. But it has to be superflexible and superextended in range to really be the last sub I am going to make. I have an idea, but it's not ready to be published yet. And I need help...
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Old 13th June 2013, 05:59 PM   #117
DrBoar is offline DrBoar  Sweden
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Drywall is used in inner walls apartments and houses. Henceforth I will use "drywall" as "Gyproc" is a brandname. 6mm drywall is used for refurbing rough surface before painting or putting up wall paper. At 6mm the structural strengh is not much. The standard stuff of drywall is two sheets of thick paper/ cardboard with plaster in between. Then there are variation that are harder, fire resistant, weather resistant and so on. The accoustic installations I have seen by gyproc and knaufdanogips use standard drywall board but the attachment kit creates an elastic monting.
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Old 15th June 2013, 03:40 AM   #118
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Amp is repaired so hopefully some measurements tomorrow...
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Old 15th June 2013, 07:43 PM   #119
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Speaker and amp are finally home, and my initial concerns about BSC appear to have been unfounded based on listening tests in my room. Bass response is very good. Here's a FR graph from close to my listening position, so this represents a LOT of room interaction. There's also a chance that the placement of my stereo is actually choking the horn output. I'll post a picture of the horn and its room placement soon...
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File Type: jpg W5 corner horn.jpg (149.8 KB, 108 views)
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Old 15th June 2013, 11:48 PM   #120
xrk971 is online now xrk971  United States
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That looks pretty good Chaz. Can you show us measurements of horn mouth output only?
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