veeman

iTrader: (3)

Definitely heat build up is the main issue. Even in decks with fans and the amp turned off, there is still a large amount of heat built up. I can assure you that with the amp running at 2 ohms for any reasonable amount of time would cause some heat related problem.

As for the 140db deck system...I have to see it to believe it.

wasted911

iTrader: (2)

Well I currenly have an older Kenwood deck running at 2 ohms right now (1 set of speakers and 1 set of tweeters) however I'm not using my rear channels. It was a temporary unit that lasted longer than I intended, but it's held up fine.

veeman

iTrader: (3)

^^the tweeters are not much of a load, and since you don't have the rears hooked up...the internal amp is not getting too much of a workout.

Haunz

iTrader: (3)

I would expect that running 2 of 4 channels at 2ohm would be the most dangerous... although if the fets can take it then the fets can take it! (I don't know one way or the other if most can or not)

running all 4 channels... well, since your HU has a limited amount of current it can provide there is a distinct possibility that you will get less clean power out of the HU before it clips....

Edit: also veeman is correct in his assertion that the HU should be seeing about 4ohms overall, even with a 4ohm tweet in parallel...

[ December 29, 2005, 02:04 PM: Message edited by: Haunz ]

SQ Civic

iTrader: (3)

Now I'd really like more info on this idea... Not that I want to do it by any means, but most HU's that have internal amps are putting out what; 16-20 watts per ch.? so if you bridge the rear ch.'s and run a sub off it, isn't the sub only getting like 80 watts at 2 ohm?? that seems a little low for a 140 db count.

Mark

Pioneer Guy

The vehicle was built by Haney Sewing & Sound years ago when the first MOSFET CD player came out from Pioneer. I think they either ran 12 or maybe even 16 twelves off of it just to say they could. Keep in mind that becuase this was measured years ago, it was on the old scale using a mic & not a sensor.
As far as power goes, Pioneer rates the subwoofer output from the mono rear channel at 70 watts @ two ohms.
I've seen it done on a pair of twelves before & a co-worker of mine runs his two eights of his head unit. I don't think anyone is claiming "competition level" performance out of this setup but for those with smaller budgets it can accomplish getting subwoofers into a car while saving up for a dedicated amplifier.

Stearnzy

most decks will be able to run at two ohms no probelm i havent seen to many that wont do it. if you look at it this way take a plymoth laser for example has 3.5"on the dash and 5.25" in the door replace those both with aftermarket speakers and a new deck and i have never had one not work. now at full boar im shure your gona get a little more distortion and the deck might not like you very much but at a normal everyday listenig level it works great