Bi-amping vs Bridging LSi9 (Onkyo SR875).

kirko

Hello,
I'm finally looking into purchasing Outlaw 2200 amps monoblocks (link) for my LSi setup (see my sig for details). I want all of my channels amplified, so I wanted to get 5 monobloks, but then I realized that Onkyo 875 has Bi-amping and Bridging options. So my question is, do I need 5 monoblocks or can I get away with 3 and Bi-amp or Bridge my LSi9s?
I'm not even sure what the different between Bi-amping and Bridging is. The manual says that when Bridging is used, the receiver is able to drive 2 speakers and when Bi-amping is used, it's able to drive 5 speakers.
Thank you.

McLoki

kirko wrote: »

Hello,
I'm finally looking into purchasing Outlaw 2200 amps monoblocks (link) for my LSi setup (see my sig for details). I want all of my channels amplified, so I wanted to get 5 monobloks, but then I realized that Onkyo 875 has Bi-amping and Bridging options. So my question is, do I need 5 monoblocks or can I get away with 3 and Bi-amp or Bridge my LSi9s?
I'm not even sure what the different between Bi-amping and Bridging is. The manual says that when Bridging is used, the receiver is able to drive 2 speakers and when Bi-amping is used, it's able to drive 5 speakers.
Thank you.

You do not want to bridge an amp with LSi9's unless your amp is FULLY 2-ohm stable....

I am not a huge fan of bi-amping (would rather just get 1 much better amp) but if you already have the extra amps - try it out and see if you like the results....

Michael

jome

McLoki wrote: »

You do not want to bridge an amp with LSi9's unless your amp is FULLY 2-ohm stable....

I am not a huge fan of bi-amping (would rather just get 1 much better amp) but if you already have the extra amps - try it out and see if you like the results....

Michael

Hi Michael,

Can you say more on the Fully 2-ohm stable amp part? I was actually planning to bridge an amp to use it as a mono block on each speaker but I came across your post. Bi-amping is just way beyond my knowledge. Don't I have to get some external crossovers if I want to do the bi-amping?

Thanks~

F1nut

Nearly all amps when bridged are not rated to drive less than 8 ohm loads (speakers) and since the LSi's are a nominal 4 ohm load dipping to 2 ohms running an amp bridged simply isn't going to work.

Furthermore, if you're getting mono block amps you can't bridge them anyway as they are a single channel to begin with.

I would suggest you get 3 mono blocks for the L/C/R speakers and use the AVR for the rear channels as they don't do much.

schwarcw

What Jesse said!

kirko

Thanks guys. I think I'll get 3 amps for now... What should I set my AVR to when I get these monoblocks? Should I leave it at 4-ohms?

schwarcw

Here's some info from Rod Elliott at Eliott Sound Products (esp). Quote:

1.16 - Adding up the Plusses
1. Effectively (up to) twice the 'real' power of the amplifiers themselves
2. Reduced intermodulation distortion
3. Elimination of the low frequency passive crossover, its inherent losses, potentially poor linearity and crossover point inaccuracy
4. Reduction of the difficulty of the load presented to the power amplifier
5. No padding is required to align the driver sensitivities, so we are not simply wasting power
6. The damping factor is greatly improved for both the low and midrange loudspeakers
7. Complete freedom from any interaction between the loudspeaker driver (and its environment) and the crossover network
Cost savings, since complex passive crossover networks an not needed
8. Bi-wiring is included free!
9. The flexibility to choose amplifiers which are at their best within a defined frequency range
10. Ability to match amplifier power to the exact requirements of the drivers for maximum overall efficiency

I could go on (and on) here, but I shall resist the temptation. There is (IMHO) no reason to not use biamping wherever possible, from small (i.e. computer) speakers through to top of the line hi-fi. The benefits far outweigh the disadvantages in all cases.

I have seen many claims that loudspeaker manufacturers often go to extraordinary lengths to design the best possible crossover network for their products. I do not doubt that for many high-end systems, this is certainly the case. It must also be considered how much extra this costs, and we can be assured that many systems have a less than ideal network, simply to keep costs reasonable. Several times, I have seen reviews where expensive speakers use ferrite cored inductors for the low frequencies, and bipolar electrolytics are also common.

I do not consider these to be optimal or appropriate for a high quality system, and nor do many others. The truth is that cost considerations are nearly always made in any system, and much more so when the selling price becomes a consideration.

As I stated at the beginning, if you spend $25,000 or more for a pair of speakers, then we are into the "cost no object" area. Most people cannot afford such luxuries, and as a result they must settle for something they can afford. Only a very few systems will be as good as they can be, and you will pay dearly for it.

Biamping is not a simple tweak, and is not to be taken lightly. Make no mistake though, its application will improve almost any loudspeaker available, with very few exceptions.

I horizontally biamp my SDA SRS 2.3's with (2) Parasound Halo A21's and love it!

John K.

Kirko, no you shouldn't "leave" your 875 set at 4 ohms; in fact it shouldn't be there now. Contrary to what some imagine, setting a receiver at a lower impedance setting in no way optimizes it for powering lower impedance speakers. All the lower setting does is to reduce the voltage output that the receiver's power supply section is capable of. When the voltage(which is the "boss")is reduced, because of Ohm's Law the maximum current and power capability is also reduced; tests have shown that the maximum power is cut roughly in half(which may be what you're experiencing now). The reason for this setting and the warnings in the manuals is a precaution against overheating so as to meet UL(Underwriters Laboratory)requirements. So, although the possibility of overheating is reduced, so is the maximum performance capability of the unit. Despite any language in the manual the lower setting should never be used.

kirko

John K. wrote: »

Kirko, no you shouldn't "leave" your 875 set at 4 ohms; in fact it shouldn't be there now. Contrary to what some imagine, setting a receiver at a lower impedance setting in no way optimizes it for powering lower impedance speakers. All the lower setting does is to reduce the voltage output that the receiver's power supply section is capable of. When the voltage(which is the "boss")is reduced, because of Ohm's Law the maximum current and power capability is also reduced; tests have shown that the maximum power is cut roughly in half(which may be what you're experiencing now). The reason for this setting and the warnings in the manuals is a precaution against overheating so as to meet UL(Underwriters Laboratory)requirements. So, although the possibility of overheating is reduced, so is the maximum performance capability of the unit. Despite any language in the manual the lower setting should never be used.

Interesting... I actually used to have it set at 8-ohms, but then I read that it can damage my AVR (I guess what you were reffering to). So what's the setting I should be shooting for? And is it the same for application with amps?
Thanks for the input.

Systems

schwarcw wrote: »

Here's some info from Rod Elliott at Eliott Sound Products (esp). Quote:

1.16 - Adding up the Plusses
1. Effectively (up to) twice the 'real' power of the amplifiers themselves
2. Reduced intermodulation distortion
3. Elimination of the low frequency passive crossover, its inherent losses, potentially poor linearity and crossover point inaccuracy
4. Reduction of the difficulty of the load presented to the power amplifier
5. No padding is required to align the driver sensitivities, so we are not simply wasting power
6. The damping factor is greatly improved for both the low and midrange loudspeakers
7. Complete freedom from any interaction between the loudspeaker driver (and its environment) and the crossover network
Cost savings, since complex passive crossover networks an not needed
8. Bi-wiring is included free!
9. The flexibility to choose amplifiers which are at their best within a defined frequency range
10. Ability to match amplifier power to the exact requirements of the drivers for maximum overall efficiency

I could go on (and on) here, but I shall resist the temptation. There is (IMHO) no reason to not use biamping wherever possible, from small (i.e. computer) speakers through to top of the line hi-fi. The benefits far outweigh the disadvantages in all cases.

I have seen many claims that loudspeaker manufacturers often go to extraordinary lengths to design the best possible crossover network for their products. I do not doubt that for many high-end systems, this is certainly the case. It must also be considered how much extra this costs, and we can be assured that many systems have a less than ideal network, simply to keep costs reasonable. Several times, I have seen reviews where expensive speakers use ferrite cored inductors for the low frequencies, and bipolar electrolytics are also common.

I do not consider these to be optimal or appropriate for a high quality system, and nor do many others. The truth is that cost considerations are nearly always made in any system, and much more so when the selling price becomes a consideration.

As I stated at the beginning, if you spend $25,000 or more for a pair of speakers, then we are into the "cost no object" area. Most people cannot afford such luxuries, and as a result they must settle for something they can afford. Only a very few systems will be as good as they can be, and you will pay dearly for it.

Biamping is not a simple tweak, and is not to be taken lightly. Make no mistake though, its application will improve almost any loudspeaker available, with very few exceptions.

I horizontally biamp my SDA SRS 2.3's with (2) Parasound Halo A21's and love it!

Rod E is specifically talking about the benifits of active biamping where the integral passive network is completely bypassed and an active crossover used.

John K. wrote: »

Contrary to what some imagine, setting a receiver at a lower impedance setting in no way optimizes it for powering lower impedance speakers.All the lower setting does is to reduce the voltage output that the receiver's power supply section is capable of.

Correct.
It's not like another set of output transistors are brought on line in the 4 ohm setting.