Darkelf Posted September 1, 2007 Share Posted September 1, 2007 I know this subject has been posted many times but after reading through the threads I am not sure if I am clear on the benefits. I am an audiophile newbie, so any advice would be helpful. I have purchased a Denon-987 and plan to purchase some RF-82s. In the setup of the reciever, the surround back channels can be assigned to the front channels for "Bi-amping", according to the manual it will render a more dynamic sound. According to what I have read about true Bi-amping, it uses separate channels and speaker cables for the low and high frequencys? But from what I have read in this forum it appears that the two separate inputs on the RF-82s are the same and are not separate low and high frequency inputs? If that is true, will I see any true benefit from "Bi-amping" this way? Would I atleast be sending more wattage to the front channels? Thanks for your advice! Quote Link to comment Share on other sites More sharing options...
jimmy4300 Posted September 1, 2007 Share Posted September 1, 2007 There's been so much written here about this subject, and so many experts giving advice on this that it makes one's head spin. Fools biamping is what what the experts call it here. Well, as I have written before, I have a Denon 1907 and RF82s. I have them Fools biamped as you described above, and IMO, and this is just my opinion, it sounds better. The bass is stronger and the highs a little more clear. Not much, but enough so that I'm very happy I did this. Many of you will say that this is all in my head, OK, maybe it is, but I like it. The two outputs would have gone vacant anyway, so why not do this? But, if you do decide to biamp, don't forget to remove the jumping straps between the two sets of bind posts. Lou Quote Link to comment Share on other sites More sharing options...
Darkelf Posted September 2, 2007 Author Share Posted September 2, 2007 Thanks Lou, I picked the system up today. All I can say is WOW. It sounds awsome. Not sure if the biamping made a difference, but like you say those channels wouldn't have been hooked up anyhow, and I coudn't be happier with the quality of sound. Thanks for the response. Quote Link to comment Share on other sites More sharing options...
Southern Posted September 2, 2007 Share Posted September 2, 2007 I have my RF-7's bi-amped but I did not do an AB comparison to hear if there was any difference without bi-amping. Correct me if I'm wrong but with bi-amping doesn't the main speakers receive twice the output power from the AV receiver since they are being feed from 2 seperate channels? Quote Link to comment Share on other sites More sharing options...
jimmy4300 Posted September 3, 2007 Share Posted September 3, 2007 I have my RF-7's bi-amped but I did not do an AB comparison to hear if there was any difference without bi-amping. Correct me if I'm wrong but with bi-amping doesn't the main speakers receive twice the output power from the AV receiver since they are being feed from 2 seperate channels? According to our electrical experts here, you're wrong. Do a search and you'll see why.Lou Quote Link to comment Share on other sites More sharing options...
DrWho Posted September 4, 2007 Share Posted September 4, 2007 Correct me if I'm wrong but with bi-amping doesn't the main speakers receive twice the output power from the AV receiver since they are being feed from 2 seperate channels? Nope. Think of the voltage amplification instead of the power ratings. Ultimately, a power rating is just telling you how much heat is being dissipated... Quote Link to comment Share on other sites More sharing options...
Southern Posted September 7, 2007 Share Posted September 7, 2007 I believe that I used the term output power instead of watts. If I drive a speaker (non bi-amp mode) with an AV receiver rated at 140 watts x 7 channels then the speaker will receive 140 watts. If I drive a speaker (bi-amp mode) then the lows will receive 140 watts and the highs will receive 140 watts which is a total of 280 watts delivered to the speaker. I'm only referring to the watts delivered to the speaker not the fact that the passive crossover will consume some of this before it gets to the driver. Since I am new to AV receivers I don't believe that they rate them the same way as 2 channel receivers so the AV receiver may not be capable of delivering the full 140 watts x 7 channels. Watts is misleading when it comes to sound level, in reality by doubling the watts to a speaker would only result in a 3 dB increase in loudness. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted September 8, 2007 Share Posted September 8, 2007 Wrong. The crossover is split into hf and lf sections, each with roughly 8 ohm ( nominal ) impedance. You are still applying the same amount of voltage to the each half of the crossover. 33.46 volts into an 8 ohm load, will be about 140 watts. Since there is a passive crossover, it still results in an 8 ohm nominal load when both sections are connected in parallel via the binding straps. If there was no crossover, and you connected the drivers in parallel, the resulting impedance would be lower. They would be trying to reproduce the same frequencies, and therefore have a lower impedance in the region where they overlap. The only way to get more power is to apply more voltage, by means of a larger amplifier. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted September 8, 2007 Share Posted September 8, 2007 In my case, I normally use a Phillips power amplifier, but decided to try out my QSC PLXII 3102 amp on my RF3II's. This amplifier is capable of 550 w/ch 20hz-20khz and 600 w/ch at 1khz. The result was a definite increase in dynamic range, and I still managed to get the clip lights to come on, during demanding scenes. 66.33 V into an 8R nominal load is equivalent to 550 w dissipated across the load. Quote Link to comment Share on other sites More sharing options...
MojoRisen Posted October 25, 2007 Share Posted October 25, 2007 Does the Denon reassign the unused rear surround as mains? I wouldnt want the rear sound info mixed in with the main if that was not the case. What I did was do an A/B (a=high, b=low) bi-wire (bi-amp??)and there is a distinct difference from the original 2 wire setup. I was very pleased with the results. Quote Link to comment Share on other sites More sharing options...
cotton Posted October 25, 2007 Share Posted October 25, 2007 I tried bi-amping my RB-81s and I didn't like the resulting sound. The highs were unnaturally strong and the cross-over didn't sound as smooth when going from highs to lows. Maybe if my room wasn't so problematic I would have liked the result more. BTW, this was with a Marantz 7001 Quote Link to comment Share on other sites More sharing options...
jimmy4300 Posted October 26, 2007 Share Posted October 26, 2007 Does the Denon reassign the unused rear surround as mains? I wouldnt want the rear sound info mixed in with the main if that was not the case. What I did was do an A/B (a=high, b=low) bi-wire (bi-amp??)and there is a distinct difference from the original 2 wire setup. I was very pleased with the results. Yes, you reassign them through the set-up menu. Lou Quote Link to comment Share on other sites More sharing options...
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