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Hey guys I was trolling on this board the other day and came across a suggestion to us two RMB 1075's for Biamping your front 3 channels and it kinda got me thinking about Biamping. I have one 1075 but don't really want to spend the $$ on another. So, I stumbled across a 1066 that can be brigged into a 3 channell 150 watt amp or a rmb 985 that is only 100 watts. Since neither one is exactly the same as the 1075 am I wasting my time? What problems would that create if say I have the 150 watts to the bass speakers and the 125 of the 1075 to the tweaters or visa versa. If this makes any sense at all please advise.
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As mentioned in the other thread, bi-amping with out using a cross over before the amplifiers only nets you marginal gains. To do a proper Bi-amp, you must separate the low and high frequencies before amplification with an electronic cross over, and then send them to your speaker's network that has also been modified to separate the Bass from the Mid Highs. If your speakers are bi-wirable, then the work at the speakers end could be done (edited) for you.
Of course you can just connect the bi-amps up in a bi-wire configuration and let her buck, however the costs for performance aren't really worth it. The amps in this arrangement must still amplify the entire full range frequency so they would not be gaining any head room, as if they would if the amps only had to amplify a portion of the frequency range. You would be better off to spend the money on a more powerful amp in that case.
As to the disimular power ouput of the amps, I think it will be ok, as higher frequencies (mid-highs) tend to use less power than lower ones (bass). More importanty is the setup of your cross over frequencies.
This is a good resourse that is very digestable...Last edited by Bing Fung; 30 June 2004, 23:43 Wednesday.Bing -
Ditto what Bing said re: "true" biamping, unless you've already got the two amps. Going out and purposely buying two amps and not doing a "true" biamp is a waste of money. Just buy one, more powerful amp.
As for different power for highs vs. lows check with your manufacturer as every speaker is different. Some may have the crossover set up to apply more juice to the lows where as some may be set up with a 50/50 split.
JasonJasonComment
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Thanks for the resonse's and Bing thanks for that link. That a pretty in depth article and will have to digest that a bit before proceeding.
Great advice though and much appreciated :TComment
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Good point on the actual speakers requirements Jason :T Typically the bass does take more power, but it can be different based on how it was designed. :T
Foxman, you're welcome 8)BingComment
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bi wired speakers
when bi-amping using the active crossover even though you may have bi-wire capable speakers, you still need to get in there and remove the passive crossovers from the speakers for the best performance otherwise you will have each side going through 2 crossovers (passive & active). If you have three way speakers you will either have to get three amps and a 3X crossover or keep the mid to high passive crossover and use the bi-amplification. different power amps are more usable than same power rated amps. the higher you crossover setting the less power to the tweeter( which can reach 80% bass to 20% tweeter ) so you can see different power rated amps can be more beneficial as you mate the power rating to the crossover point. I use a rb-1075 and a rb-1050 combo and I still find that even with it's extremely low crossover @800hz I still need to back off the 1050 power to sonically match the bass running on the 1075.... end result is a vastly improved sound... my 2 cents worth....Get the most BANG for your BUCKComment
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Agree :TBingComment
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So, since I have a two way Bi-wireable speaker it sounds like the all I would need in addition to another amp is three active crossovers between the pre/pro and the amp? or would one crossover be enough for all three front channels since I would be using two multi channel amps instead of three amps?
ops: Or am I just confused?
RSP-1066, RMB-1075
Klipsch RF-7, RC-7, RS-7
SVS 20-39PC+Comment
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Foxman,
Ok, here is the deal you will need to remove the four screws off the back holding the the bi-wire input, now when I did it I unsoldered the wires from the crossover but it may be easier if you cut (leave room to reattach if necessary) then patch the low end speakers together in parallel and attach to the low input connector and then attach the horn to the hi input. you will need to do this for every speaker you bi-amp. Be sure to get an active crossover that has the exact crossover point as your Klipsch's....hope this clears things some....Get the most BANG for your BUCKComment
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Generally it is said that you can keep the passive cross over between the Mids and highs and only need to separate the bass form the mids, so you would only need 2 active cross overs per speaker.
However 3 would be the purist way to do it, although not totally nessesary.BingComment
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I have a hard time understanding the basis for saying that the amp would not see any improved headroom unless the signals are filtered prior to the amp input.Originally posted by Bing Fung
Using the speaker's crossover, the amp going to the mids/highs will effectively see an increasing impedance as the frequency drops below the crossover point which translates into reduced current draw at low frequencies which should translate to increased headroom. The same argument should hold true for the amp going to the woofer having a reduced load at mid/high-frequencies.
Am I missing something here?Comment
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No, you have it right, to a point. However the way i understand it is the amplifier still has to amplify the entire range sent to it, then have the Cross Over strip out what it requires. Done in this manner the gains are marginal in the above senerio.
I use to have my system Bi-amped in that manner (Amplification before XO) and the performance gains were only slightly noticable at the extreme volume levels. I had 105W going to the Tweeter/mids, and then 120 Watts going to the bass Woofer. In tests with just the 120 Watt Bryston driving the whole speaker rather than bi-amed, with the extra amp, The single amp really didn't lose any ground in actual out put. Sonically at normal to louder listening levels I was hard press to tell any difference.
So I should have said the amp gains some head room albeit marginal, it's not as big a gains if you were to XO before the amplifier, so then the amp only has to amplify the cut off frequencies for the selected bands.BingComment
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really informative link on the plusses and minuses of bi-amping and overall theory behind it...enjoy
Get the most BANG for your BUCKComment
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Good article. I see where the benefit of an active x-over before the amps comes in now.
BTW, Bing, where the hell are you in your picture? It sure isn't anywhere in Saskatoon from what I remember (there's no black fly as big as your head in the background).Comment
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Chris, What, you think Saskatoon and Saskatchewan is Flat or something?
Or we have large insects? 
:
I'm driving south on the HWY1 through Banff National Park, North of Lake Louise.
I'm driving my buddy's Porsche Boxster (who lives in Calgary), he just snapped the picture for something to do. We had just finished a Helicopter Hiking Tour that was given to him from his wife for his birthday. It was a great time 8)
BingComment
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Originally posted by rotel_klipsch
That does clear it up. Sounds fairly simple. Now its a matter of about 1,000.00 and convincing the Mrs. :TComment
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Anyone here familier with the Behringer DCX2496 Ultradrive Pro electrionic Crossover? If so, is this pretty much the best buy for the money, or are there other alternatives.Comment
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Behringer gets mentioned alot on the budget side, but mostly for EQ's for subs. They are known to be a little noisy for high-end audio..
Look on Ebay for a Rane AC-22, it's a really nice stereo two-way crossover that you can usually pick up for under $100 used. Retail is around $300 I believe..
Kevin D.Comment
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