2269 driver displacement

Can someone tell me which t/s refers to driver displacement? Or, does anyone know what it is for the 2269? TIA

Hi gasfan,

if you refer to volume displaced by driver in the box, conventional 18" was rated by jbl at 0.3 cu.ft. or 8.5 L. You may need to adjust that number somewhat for the 2269. Hope this is of some help to you. Regards,

Richard

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Originally Posted by RMC

Hi gasfan,

if you refer to volume displaced by driver in the box, conventional 18" was rated by jbl at 0.3 cu.ft. or 8.5 L. You may need to adjust that number somewhat for the 2269. Hope this is of some help to you. Regards,

Richard

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Okay, thank you.

-If- the question is re Vd, then it’s Sd * Xmax, but the intended question may have been answered.

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Originally Posted by grumpy

-If- the question is re Vd, then it’s Sd * Xmax, but the intended question may have been answered.

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Strange it would be a calculation when there are designated parameters. Confusion is my alter ego:blink:

Many of the parameters are interdependent.

If you want to know about accounting for box volume, RMC pointed you in the right direction.
... something like the volume of a cone plus the magnet structure size.

If you want to know how much air is moved at xmax displacement, Vd is the value. Much like piston diameter and stroke in concept.

Quote:

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Originally Posted by grumpy

Many of the parameters are interdependent.

If you want to know about accounting for box volume, RMC pointed you in the right direction.
... something like the volume of a cone plus the magnet structure size.

If you want to know how much air is moved at xmax displacement, Vd is the value. Much like piston diameter and stroke in concept.

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Thanks I did not know that. I knew what the 2245 displacement was because it's published so I expected the same for the 2269. However .3 is probably close enough for both just because of tolerance.

Hi gasfan,

Both E-V and Eargle (Loudspeaker Handbook) indicate that +/- 5 % on box volume has no material effect (E-V) or can be neglected (Eargle). So with 0.3 cu ft or 8.5 L for an 18" (from JBL Conversion Constants and Useful Data) you're pretty much in the ball park.

I did try a few times one of the volume displacement calculator on the Net (can't remember which one, maybe DIY Audio? not sure though) and the results seemed pretty much off, some by 50%, so I prefer using manufacturer data when available. In absence of mfr data then a more or less accurate calculator is still better than a wild guess since you have a 5% box volume error margin.

Btw I do like Grumpy's piston dia. and stroke analogy: mechanical engineering, resourceful fellow. Regards,

Richard