Re: Re: Re: the brick
The only thing off with the 3" Bamboo is the vas. It's .01 liters too much so I would imagine that the dimensions of the cabinet would have to be changed. I love that little cabinet. Is there anyone that would be kind enough to model one with the W3-1364SA as the driver?
planet10 said:
The only thing off with the 3" Bamboo is the vas. It's .01 liters too much so I would imagine that the dimensions of the cabinet would have to be changed. I love that little cabinet. Is there anyone that would be kind enough to model one with the W3-1364SA as the driver?
planet10 said:
Scottmoose said:
It was my understanding that a ML-TL (mass loaded transmission line) used a TL form but a much smaller "open area" or an actual port, which is not the case with the Pensil which is a line with an equal open end. Everything about the Pensil points to the QWTL. I'm obviously missing something. Perhaps you could provide a link that would identify the distinction differently so I could understand why the Pensil is not applicable to MJK's tables.
AdamThorne said:
Well, I've searched "LKO-120WFF" and "299-280" and "Peerless India" but it looks like I'm going to have to ask Lon (or anyone else) to point me in the direction of other discussions of these drivers.
Looking forward to improved search after the forum upgrade...
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-280
Parts Express is in Ohio... no need to go to India as far as I know.
PE also has a forum for their stuff. If a more detailed data sheet is needed than the specs in the description, some leads may be gotten there. In their a-b-c measurement system, B is usually the size of the cutout needed.
More than that I don't know myself.
If the link doesn't work right, go to www.partsexpress.com
and put the number 299-280 in their search box.
Report back with anything else you need.
OK, I've just taken a quick look for the sake of interest.
The Pensil is certainly a resonant QW line, & not an especially distinguished one at that; looks like only the most rudimentary QW math has gone into it, and it may be regarded in the same vein as the rather similar Zigmahornet. I have dark suspicions about harmonic nulls. F3 will probably be acceptably suppressed by the driver location, but higher modes will likely be more problematic.
FWIW, length / Fp has clearly been set to Fs; for the rest, it looks like raw guesswork, although, Vp appears is roughly in the region of a 4th order (reflex) vented alignment; whether that is accident or design, I wouldn't like to say.
Edit: I've just stuffed it through MathCAD for the sake of providing a few illustrative graphs.
Top plot: driver & vent output of the unstuffed pipe; you can clearly see the confirmation that the first mode is set to the 70Hz pipe tuning. Middle plot: FR of the cabinet when damped ~equivalent to plans. As suspected, note the harmonic null. Lower plot: FR of the cabinet with the same damping, but with the slight mass loading removed. It doesn't make a whole lot of difference, other than fractionally reducing the depth of the null at F5. Still, mass loading as suggested is purely a matter of degree. If there is a restriction, however slight, it's still technically mass loaded. Can't beat the laws of physics.
The Pensil is certainly a resonant QW line, & not an especially distinguished one at that; looks like only the most rudimentary QW math has gone into it, and it may be regarded in the same vein as the rather similar Zigmahornet. I have dark suspicions about harmonic nulls. F3 will probably be acceptably suppressed by the driver location, but higher modes will likely be more problematic.
FWIW, length / Fp has clearly been set to Fs; for the rest, it looks like raw guesswork, although, Vp appears is roughly in the region of a 4th order (reflex) vented alignment; whether that is accident or design, I wouldn't like to say.
Edit: I've just stuffed it through MathCAD for the sake of providing a few illustrative graphs.
Top plot: driver & vent output of the unstuffed pipe; you can clearly see the confirmation that the first mode is set to the 70Hz pipe tuning. Middle plot: FR of the cabinet when damped ~equivalent to plans. As suspected, note the harmonic null. Lower plot: FR of the cabinet with the same damping, but with the slight mass loading removed. It doesn't make a whole lot of difference, other than fractionally reducing the depth of the null at F5. Still, mass loading as suggested is purely a matter of degree. If there is a restriction, however slight, it's still technically mass loaded. Can't beat the laws of physics.
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raypalmer said:
OK, later today I'll run it through the model
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