Because I have almost no experience in this, I thought I would ask:

Aren't the large excursion, cube-type subwoofers better at aiding in the preparation of drinks that are "shaken, not stirred?"






[This message has been edited by bestbang4thebuck (edited May 27, 2004).]

Yes they are. They are also useful in frightening the crap out of your cat.

I like the large cone with the large excursion.

There is a relationship between small box size, frequency extension and efficiency where you can not have all three. Simplified version of what SH said. I'll see if I can dig up an old thread somewhere else over the weekend that had some very good info that might add to what SH said. 1/2 day Fridays! woot!

[This message has been edited by JT Clark (edited May 27, 2004).]

You can have two of these parameters, but not all three at the same time: small box size, frequency extension, and efficiency.

I sacrificed on the "small box size" aspect.

[This message has been edited by soundhound (edited May 27, 2004).]

so if i am looking at the tumult correctly it has 1.339in xmax which i would say is excursion? if that is the case, there are subs with greater excursions.

They state "one way", so the total excursion could be twice that amount if that is the correct spec.

For comparison, the total front to back excursion of my 18" JBL professional sub drivers is only 1" maximum.

[This message has been edited by soundhound (edited May 27, 2004).]

Id say that an 18 is not a small cone, yet for ht they come packaged in a relatively small enclosure. Small considering size of driver in relation to minimal box i mean. However the 18 in the small enclosure does have to have a good amount of excursion as you have pointed out so eloquently.

yeah i saw that one-way, as well, strange to put it like that... makes me think that perhaps it travels farther out, than say back inward. then you have some companies that just say excursion as one number, not each way or oneway or total.... standardization people, man how nice it would be.

i would say that servo control is a factor that makes a good sub. from my manual:
"The accelerometer (closed-loop, i put this in since it just said it above the quote) continuously monitors cone motions, providing us with a feedback signal for the servo control circuitry. This high-gain system is designed to improve linearity and reduce distortion approximately 30 times. over conventional non-servo systems. While the input signal is being sent to the amplifier which powers the driver, a continuous signal representing cone motion is being sent to a comparator circuit. This circuit constantly adjusts for any deviation between the input signal and the subwoofer's output. This self regulation results in extreme control over cone movement, and very accurate low distortion sound."

Ironically below this paragraph they talk about the amplifier as extremely efficient Class D, and cool at 1250rms. that contradicts what sh said about them being so inefficient.

here are the specs for my hgsII-18 thx ultra2:
cabinet size (h/w/d): 23.5"x21.25"x18.5"
frequency response: 15Hz-120Hz +/- 3db
harmonic distortion: less than 0.5%
subsonic filter: 15Hz or 35Hz
High Pass Crossover: 80Hz or 100Hz (6dB/octave)
Low Pass Crossover: 40Hz-120Hz (12 dB/octave initial, 48 dB/octave ultimate)
Phase: 0deg/180deg
Amplifier: Class D, 1250 watts RMS, 3000 watts peak
Woofer - forward firing: 18" (15.2" piston diameter)
Magnet: 220 oz (13.7 lbs)
Magnet structure: 380 oz (24 lbs)
Voice coil: Tandem 3" push-pull
Inputs: Line-level, Balanced & speaker-level
Outputs: Line-level and speaker-level
Weight: 115 lbs (approx)

considering that (above) and their "ultra-efficient" amplifier, id say that that theory goes out the window.