Oliver:
Thanks for the drawings and suggestions. After my episode with a -13db@40hz flh design... I don't think I can ever bring myself to build something that doesn't have lots of oomph at 40hz. The cube is actually breaking new ground for me, as it's a design that can't do 40hz with authority in singles.
I guess the 'flat to 40' habit is hard to break.
great suggestion and layout though.
Thanks for the drawings and suggestions. After my episode with a -13db@40hz flh design... I don't think I can ever bring myself to build something that doesn't have lots of oomph at 40hz. The cube is actually breaking new ground for me, as it's a design that can't do 40hz with authority in singles.
I guess the 'flat to 40' habit is hard to break.
great suggestion and layout though.
Using letter boxes always seems better.
Just more to build. (which I am a bit lazy)
magent in mouth...
So every TH I have built or theoretically played with has a better PA performance with magnet in mouth. HT setups have been the reverse. But that is probably because we model HT's in quater space rather than half and also that we want HT's to do sub sonics
and 115 DB is good. Vs 130 DB at half space at 40 Hz.
As far as mounting the driver opposite
wall. It becomes the TH Mini then. So it shouldn't cause any effect whatsoever as long as path doesn't change.
Wish I had time to knock one of these out.
Got to finish my other things first.
Just more to build. (which I am a bit lazy)
magent in mouth...
So every TH I have built or theoretically played with has a better PA performance with magnet in mouth. HT setups have been the reverse. But that is probably because we model HT's in quater space rather than half and also that we want HT's to do sub sonics
and 115 DB is good. Vs 130 DB at half space at 40 Hz.
As far as mounting the driver opposite
wall. It becomes the TH Mini then. So it shouldn't cause any effect whatsoever as long as path doesn't change.
Wish I had time to knock one of these out.
Got to finish my other things first.
Yee Ha !!!!
The cube tests better at 40hz than I would have thought! With no reflectors in, it's a 'little' stuffy at 80hz -- Other than that, 99db@40, 101@50, 101@60, 100@70, 98@80, 99@90, and 100@100. Have to cycle through the 1hz tests yet. (I listen to each 1hz increment with sine waves, to determine what I do and don't like out of a sub.) I also typically 24dbLR low pass at 90-95 hz on my subs, so above 100hz is of little consequence to me. Also, it looks like it is directional, -6db at 120 degree, and about -10 at 180.
From doing this in the past, adding a reflector or two close to the driver will help 80hz at the expense of 40hz...
not sure it's worth it to add reflectors... I'm such a 40hz nut.
The cube gives up 2-3db across the board vs the big cab... But I can tell already that my back will be happier installing.
The cube tests better at 40hz than I would have thought! With no reflectors in, it's a 'little' stuffy at 80hz -- Other than that, 99db@40, 101@50, 101@60, 100@70, 98@80, 99@90, and 100@100. Have to cycle through the 1hz tests yet. (I listen to each 1hz increment with sine waves, to determine what I do and don't like out of a sub.) I also typically 24dbLR low pass at 90-95 hz on my subs, so above 100hz is of little consequence to me. Also, it looks like it is directional, -6db at 120 degree, and about -10 at 180.
From doing this in the past, adding a reflector or two close to the driver will help 80hz at the expense of 40hz...
not sure it's worth it to add reflectors... I'm such a 40hz nut.
The cube gives up 2-3db across the board vs the big cab... But I can tell already that my back will be happier installing.
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Don:
'By accident' in the past, I've come up with better 40hz by not trying to keep the expansion exactly conic when building. Your drawing a few posts back is much more linear than what I did.
Here's some pics with some braces just put in. Have to wait till the glue dries before I know if they affect the sound any or not. I decided against reflectors, and to leave the 40hz alone.
'By accident' in the past, I've come up with better 40hz by not trying to keep the expansion exactly conic when building. Your drawing a few posts back is much more linear than what I did.
Here's some pics with some braces just put in. Have to wait till the glue dries before I know if they affect the sound any or not. I decided against reflectors, and to leave the 40hz alone.
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Not bad at all! I wonder if the "shading" of the mouth by the driver contributed to the lower F3 point?
What's the external dimensions of the box BTW?
Those angles are so close to square, I wonder if it's possible get away with implementing it as a stepped tapped-horn instead, with little loss in the passband?
OK, glue is dry here's the 'final' numbers with braces in place.
2.83v, 1M, sine wave test tones outdoors over grass, spl meter.
(non broken in 3015lf)
30hz 87
40hz 98
50hz 100.5
60hz 100.5
70hz 99.5
80hz 98.5
90hz 99
100hz 100
110hz 102
120hz 103
130hz 102.5
140hz 101
150hz 98.5
160hz 93
170hz 83
yea, oliver it takes a dive at 160hz, but then I don't much care the way I run subs. For a live band that crosses subs up higher than I do, it would be an issue and some tweaking would be in order.
It's a 24" cube and don posted what is probably a 'better' set of dimensions than what I actually built a few posts back.
2.83v, 1M, sine wave test tones outdoors over grass, spl meter.
(non broken in 3015lf)
30hz 87
40hz 98
50hz 100.5
60hz 100.5
70hz 99.5
80hz 98.5
90hz 99
100hz 100
110hz 102
120hz 103
130hz 102.5
140hz 101
150hz 98.5
160hz 93
170hz 83
yea, oliver it takes a dive at 160hz, but then I don't much care the way I run subs. For a live band that crosses subs up higher than I do, it would be an issue and some tweaking would be in order.
It's a 24" cube and don posted what is probably a 'better' set of dimensions than what I actually built a few posts back.
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you CAN'T run this sub at 30hz, or you'll grenade it. 40hz high pass 24db/oct or better.
I'm sure Brian's right, at least for under 100 Hz. My drawing is an exact implimentation of the HornResp simulation, but small "errors" in building
would not be significant. In fact, they might result in improvement.
Is this for a stack of 4? Jim has a technique that has served him well. I don't think my method is "better" but it may be a little easier for new builders.
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Don: I say your dimensions are 'better' as the bend at the upper/back corner isn't a good transition with the dimensions I used...
Working on some tops to go with these... I kinda think a pair of cubes would be a nice base (at least looks wise) for a dual driver top, 30degree toe in on each side of a wide stage -- no stands needed. We'll see.
Working on some tops to go with these... I kinda think a pair of cubes would be a nice base (at least looks wise) for a dual driver top, 30degree toe in on each side of a wide stage -- no stands needed. We'll see.
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