Tri-Mode Operational Output??? ...or bridging???

[sumone 10+ year member]

Just got my usx4065 today. 65Wx4ch. Got the cdt-61s a couple days before, so I've just been browsing through the manuals and planning my install. however, I got to the page in the 4065 manual where it shows how to wire for tri-mode operational output ("a unique feature which allows a subwoofer to be operated in mono mode, while the main speakers are playing in stereo") and it looked nothing how I thought it would.

I thought: Hook up up cdts to channels 1 & 2. bridge the sub on 3 & 4. in other words, (2) positive/negative sets going into corresponding channels 1 & 2, then a wire from sub going to negative of ch3 and other wire going to positive of ch4.

I looked at the book and didn't understand it. from the looks of it, it looks like they run 2 speakers and 1 sub off channels 1&2, and another 2 speakers and 1 sub off of channels 3&4. So in total, they're running 4 speakers and 2 subs. I guess if I had 4 speakers and 2 subs, that's how I might wire it, but what about in my case? 2 speakers and 1 sub? Am I still right with doing each speaker on their own channel, and the sub bridged over 2 channels?

I tried to attach a picture of the page in the book but it wouldn't work.

It's still going to be some time before I try and install this stuff since I'm waiting on my sub and kick panels to come. [and a box]. Also since this will be my first installation attempt and it's cold as hell outside and snow on the ground I still gotta wait some more.

Click to read more...

 

[sumone 10+ year member]

here's a picutre of it: here

2nd try

3rd try

you may have to open a new window and paste the link

sorry for the horrible quality - I'm an inexperienced digital camera user

 

[nosaj070 10+ year member]

It seems there are lots of questions on this. Tri-mode allows you to run 3 speakers off of 2channels. The power is divided in half, half goes to the 3rd speaker( usually sub) and then the other half, is then divided in half again, and goes to the two speakers in stereo. Usually this is pointless because its not really enough power for the sub, and makes a whole lot more sense to just buy another amp for the sub, or in your case a 4ch. You're best bet is you just do like you said, run speakers off of 1&2, and bridge the sub on 3&4, good luck.

-Jason

 

[xploit2 10+ year member]

sumone thats exactly what im trying to do I can do that with my pic2.440 (tri-mode) but the thing is that u have to set the crossover (on the amp) to FULLPASS and then get a COIL the will block the highs from the SUB. the only thing though is that those COILS take a lot of power. SOME PEOPLE tell me that my amp will get too hot! I doubt it though since it runs hella cool i can play music for 2 hours straight on my amp till it starts getting hot so that makes me think it will be OK. naother thing I found out is that the SUB NEEDS TO BE WIRED 8OHM. anyone else knows how to do this I need some more INFO on this //content.invisioncic.com/y282845/emoticons/smash.gif.499e08a4a35ffaf54f4c8194fb8fe8ed.gif

 

[xploit2 10+ year member]

sumone thats exactly what im trying to do I can do that with my pic2.440 (tri-mode) but the thing is that u have to set the crossover (on the amp) to FULLPASS and then get a COIL the will block the highs from the SUB. the only thing though is that those COILS take a lot of power. SOME PEOPLE tell me that my amp will get too hot! I doubt it though since it runs hella cool i can play music for 2 hours straight on my amp till it starts getting hot so that makes me think it will be OK. naother thing I found out is that the SUB NEEDS TO BE WIRED 8OHM. anyone else knows how to do this I need some more INFO on this //content.invisioncic.com/y282845/emoticons/smash.gif.499e08a4a35ffaf54f4c8194fb8fe8ed.gif

 

[sumone 10+ year member]

cool, thanks - just wasn'rt sure if I had to do all that extra work and stuff

 

[xploit2 10+ year member]

more info here => TRI-MODE AMP CONFIG

 

[helotaxi 5,000+ posts]

sumone- You are correct in your initial idea. Run 1&2 as normal to the front speakers. Bridge 3&4 to the sub. Trimode is pointless on a 4 channel amp, eventhough it can be done. It requires a passive crossover network to work correctly and you already have the active on the amp.

Nosaj070- If properly configured, there is no "division of power" in a trimode setup. You use a passive network to divide the signal between the sub and the high-freq speakers and both get full rated power (stereo power for whatever the impedance of the high-freq speakers is and bridged power at whatever the impedance of the sub is.). Example: I used to run a CO230 amp this way. My front speakers each got 30w RMS (rated power of the amp at 4 ohms stereo) and the sub got 120w RMS (rated powerof the amp at 4 ohms mono). If this network is designed correctly the amp is just as stable into a 4 ohm sub as it would be without the other speakers on there. Now if you don't run any kind of passive network, you have to worry about final impedance as the separates will effectively be wired in parallel with half of the impedance of the sub and present the amp with a low impedance that it possibly cannot handle. Using the example above, without the passive network, each channel would have "seen" 1.33 ohms (4 ohms and 2 ohms in parallel).

This was really common about 10 years ago in the real low power classes in IASCA. The Speaker Warehouse (JL Audio) Blazer ran 42 speakers, including 8 10W5 subs, off one 2 channel PPI ProMOS 100 amp. The passive network was HUGE. The coil for the sub crossover was about 6" in diameter and a foot long and the high frequency filters were laid out in an area about 18"x36". Final impedance was about .7 ohms per channel at 80hz and above and 1 ohm below 80hz.