?? Tri-mode ??

[generalGOTCHA 10+ year member]

Ok , I have two 10" Orion P series 500Wrms subs, and I have an older XTR3 12" 500WRMS subwoofer.

I have seen peoples setups where there is a 12" woofer in the center and two 10's on the outside of it.

Heres the specs though !

Both P series 10" subs have duel 4 ohm voice coils.

The single 12" Orion Xtr3 has a single 4 ohm.

could I make this possible ? I mean these 10's make me completely happy, I could do without the 12, but I really want to include it into the system even if I have to completely rebuild the box.

ADDITIONAL QUESTIONS:

- How does tri-mode work ? Would the center subwoofer get the most power ?

How is the power dispursed ?

If there is a way to use this 12" single 4 ohm subwoofer included with my two 10's whats the pro's cons or electrical consumption. My system is currently running on an old Orion HCCA 250G4 @ 1 ohm

Click to read more...

 

[thch 10+ year member]

trimode is a creative way to get stereo sound to a set of full range speakers, as well as get a high power mono signal to a single woofer.

It is rarely used because the filtering of vocals from the woofer, and the filtering of bass from the full-ranges is done post-amplifier, which requires large expensive passive components, and increases losses.

Further, it is more complicated then most users would like, and users technically minded enough to understand it are put off by the technical disadvantages.

basically, two speakers are attached, one per channel. the third speaker is attached across the two channels in a "bridged" configuration.

for technical purposes, concider that the output of ch1 will be the difference of +V and 0V, and the output of ch2 will be the difference of 0V and -V. (+V-0 = 0 - -V, thus the signals are the same). bridging simply uses the +V and -V terminals, getting +V - -V = +2V out.

if you had a DVC woofer with coils attached in series, there would be +2V across the woofer, with +V across each coil -- just as if each amp channel had been attached to a single coil! thus a speaker attached to a bridged channel appears as 1/2 of its actual impedance to each of the bridged channels.

for this reason, many manufacturers list the minimum woofer impedance as 8ohm, and the speaker impedance as 4ohm in trimode. half of 8ohm is 4ohm. two 4ohm loads in parallel gives 2ohm, which is the minimum load on each channl of a typical 2 channel amp. This is a valid analysis when there is no filtering.

for your purposes, the setup will (probably) place excessive load on the amp. if the amp is stable with 1ohm loads (stereo) then you will be fine. the 12" would receive equal power as the 10s combined (2x each 10 seperately). alternatively, the 10s could have coils in series, in which case the 12 would get 4x the power of the 10s combined. (8x each 10).

 

[thch 10+ year member]

hmm. seems the amp is pretty powerful. so it could work. moving the 10"s to stereo channels would reduce power output overall (would appear as a 2ohm bridged load). thus overall power would go down by a factor of 2. if the amp is stable to loads less then 1ohm bridged, you could attach the 12" in parallel with the 10"s. the combination of 10s would get 4x power of the 12". (2x more per 10)