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I read the manual, but couldn't get the answer. Hopefully you guys can help me out.
My HK PA5800 amp can do 100WPCx5 in 8ohms and 150WPC x5 in 4ohms. not bridgeable. The lsi15 is 4ohms normally. the owner did the woofer mod with db840.
with that said, if I remove the jumper to bi-amp using 4 channels out of my amp. is it still 4 ohms for the top 2 mids+tweeter, and 4ohms for the woofer ?
I am hoping that the top part will act like the Lsi9 and get 150W, and the woofer will get its own 150W.
Although I do not know the answer, that is a good question. I do not remember ever seeing this question about the impedance after the jumpers are removed.Quote:
Originally Posted by nhhiep
Buy two separate amps with the same gain and two active crossovers. Remove the passive crossovers and wire the highs to the top binding posts, lows to the bottom posts. Hook everything up and dial in the active crossovers.Quote:
How to bi-amp Lsi 15?
IMHO you don't hafta replace your amp. To Bi-amp correctly the passive filtering hasta go. Active stereo XOs w/adjustable outputs for the HP & LP can be had. Try Behringer's CX2310 - under $100 on eBay
Regarding your impedence/power questions: if they're 4 ohm drivers, they should see the higher numbers though, depending upon the XO frequency & filter steepness (6/12/18/24dB/octave) I doubt the top would see 20% of the bottom.
Have fun w/it! Tony
Well simply converting a speaker to fully active does not garantee superior results.As with a properly designed passive crossover the roll off slopes, crossover frequency,driver offset,phase etc. all have to be taken into account.Otherwise the result could be far inferior to the original passive ntwork with poor frequency response and out phase drivers etc.
As for impedances with the jumpers removed,each section will have the same impedance as it did with jumpers installed but now each amp ch will only have to deliver current to the frequency range of that driver and it's crossover section.
I think you guys are complicating things. I have no intention to modify the xo or get into active/passive bi-amp thing. all I want to know is what is the ohm reading with the jumper removed
Guilty as charged,but sometimes discussions get off in a tangent here.Quote:
Originally Posted by nhhiep
Don't get hung up on the numbers. Just realize you let a lot more electrons flow freely and you removed that "back flow" from woofers up to high end. It will RWEALLY warm up the sound. I have 2 Carver M220t's and each one is biamped to 1 speaker. Sounds damn near as good as they did with my Mac MC352.
If you have the extra two channels to use "bi-amping" your LSi15s, your speakers would benefit from them over just using two channels and the jumpers.
Because your not really going straight from the amp to the drivers (you still have the crossover engaged) I believe its still a 4 ohm rating. It isnt until you remove the crossover and go straight amp to drive that the impedance changes.Quote:
Originally Posted by nhhiep
Correct me if I am wrong.
P.S. I have done exactly what your talking about doing using my Carver AV-705x and honestly noticed no difference in the long run at normal volumes. I also know some folks that have done this concept on other speakers and we all agree you dont really notice any differences till you get to crazy stupid volumes as the speakers dont run out of power as quick with 2 channels.
Personally I just decided to go all in and purchased a Carver M1.0t and had it refurbed (its arriving today). I figure with 500 wpc @ 4 ohms I will have all the headroom I need for the 15's.
Plus if you use 2 channels you need 2 sets of speaker cables and depending on what your using that can get expensive (I went with bi-wired Kimber Kable 8VS myself :biggrin:)
I am just trying to utilize unused channels of my amp. If it's still 4 ohms with the jumper removed, then I think 150 W for top and another 150 W for the woofer is good. I am afraid that it will be 8 ohms, thus reduce the Watt by 1/3. BTW, I don't have the speakers yet, will be here in a week or so.
I am using monoprice 12AWG wire.
The wattage is less important than the effect my friend!
Try it both ways, but in all honestly because your still using the same powersupply for them either way you wont really notice the difference either way. I think you will be surprised with how it sounds on just the standard run of speaker cable.Quote:
Originally Posted by nhhiep
My 705x is only 125x5 and I finally exhausted the amp using direct mode on my reciever and it was at about 115 db at the main listening position when that happened (I measured with a SPL meter).
I think you will be fine with just running it off 2 channels. If nothing else maybe look into building some DIY passive subs using the other two channels.......
nhhiep, read this.
http://sound.westhost.com/bi-amp.htm
Then, read this.Quote:
I am using monoprice 12AWG wire.
http://www.polkaudio.com/forums/show...olor-over-time.
WQhat I was saying. I read that entire article a few years back fbefore I biammped and the effects are wonderful. For 2 old biamped Carvers to sound so close to a true audiophile piece like my Mac MC352 is impressive in every way!!
You will have 150 AVAILABLE for the top. Again, depending upon XO frequency and slopes, as you move up the frequency spectrum power requirements go down.Quote:
Originally Posted by nhhiep