|
Speaker Asylum General speaker questions for audio and home theater. |
|
|
|
Speaker Asylum General speaker questions for audio and home theater. |
|
In Reply to: Speaker stands?? posted by jsm on November 12, 2000 at 17:24:04:
hello jsm,I will not tell you that heavy steel or mass loaded stands WILL sound better, but if one looks at the the dynamics involved, and uses some "real world data" there is certainly very strong reasons to prefer heavy stands.
At the risk of inciting a riot here goes:
At typical loudspeaker cone velocities, acceleration and masses cone motion will certainly obey (in broad terms) Newtons Laws of Motion.
*(significant cone flexure, energy losses via heat and air resistance are discounted in the following simplistic analysis).As already metioned in one of the responses on this thread, bass frequencies require large cone motion and as a result woofer voice coils will need to supply greater force to move their massive cones (compared to higher frequency drivers).
I will therefore take some data for a woofer to illustrate a point. Use the FOCAL 15VX as an example (used in Wilson Grand Slam), this is a 15 inch woofer with:
Freq Range 18-1500 Hz
Power handling =275 Watts
Moving mass= .1316 kg
Force Factor (BL product)= 19.1 N/A)
Impedance 8 ohm approx.At max power input 275W, the current being drawn by the driver is given by, P=I^2xZ, i.e: I=SQRT(P/Z), I=SQRT(275/8)= 5.86A.
Since the force factor is 19.1 N/A, thus the force accelarating the cone (subject to the simplifying assumptions already made above, see "*" and maybe some others I haven't thought of yet) would be 19.1 N/A x 5.86A = 112.0 N (The equivalent of 11.41 kgf. wt). The accelartion of the cone would be given by F=ma, i.e: a=F/m=112.0 N/0.1316 kg= 851.1 ms^-2 (an accelartion of 87g!!!)
Well what does all this $*!% mean? At max power a force of 11.4 kg wt is being exerted on the air by the cone. This force will also generate a reaction force onto the speaker cabinet and it is HERE that any added mass will reduce any tendency for the cabinet to move. For this to be most effective the speaker should be intimately coupled to any heavy stand (i.e: screwed or bolted). Yes blu tak , gum etc, will work to a point, but here you are relying on the friction coeff. of the interposed material. I do not feel the stand has to be steel, but this is a good dense material. You could also use concrete, bricks etc to add mass. Although attractive from a density point of view I would never use lead for health reasons.I Hope this helps.
HAVE FUN,
JOEY
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- YOU ASKED FOR IT L....O....N....G Re: Speaker stands?? - JOEY 04:43:59 11/14/00 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
