Bi Amping

[Scolburn79]

Hi knowledgeable people,

 

My current system comprises of the following:-

 

Yamaha RX A3070 Receiver

B&W 683 S2 Front Towers

B&W HTM 61 s2 Centre Speaker 

B&W 686 s2  Surround Speakers

B&W 686 s2 Surround Back Speakers

Tannoy CVS6 Overhead/Atmos Speakers

 

These are all currently running off the Yamaha. If I Bi Amp off the Yamaha I will loose a channel for my Atmos speakers. I was speaking to my local HiFi place and they said that I could use the front speaker terminals of the Yamaha to power the Top end of my Front Towers and use an Emotiva Bas X A300 unit (2 x 150w rms) to power the bottom end of them by plugging into the front RCAs as they run at the same time as the front speaker terminals. Has anyone done this? I can't afford a big amp to run the fronts So let. When I can I can move this amp to another speaker set. Thoughts on this setup?

[almikel]

are you trying to Bi Amp or Bi Wire?

Bi Amping implies some sort of crossover before the amp - electronic or passive line level - and not using the passive crossover inside the speaker

 

Bi Wiring means disconnecting the jumpers on the back of the speaker and running separate speaker wires from the amp to each terminal (top end and bottom end), but still using the passive crossovers in the speakers - usually from a single (stereo) channel on the amp - you could use 2 channels on the amp if they had the same input signal.

 

Bi Amping has multiple advantages, but requires another low level crossover and disconnection of the speaker's internal high level crossover

https://sound-au.com/bi-amp2.htm

 

Bi Wiring IMHO has marginal benefits - I wouldn't bother.

 

For sure investigate a better amp to drive your mains if the Yammie has pre-outs after the volume control, but don't bother with Bi Wiring

 

cheers

Mike

 

[robmid]

Hi.

 

I have bi-amped a pair of Hypex amps. One dedicated to bass and the other to an ESL panel using the same passive bass and treble crossovers as I previously used with a single amp. However, I have added a 20 turn trimpot between the StereoCoffee LDR preamp output and bass Hypex inputs on the more sensitive bass speaker which allows me to trim bass/treble balance with precision.

 

The result is very seamless.

[Scolburn79]

I want to remove the strips on the back of the front speakers separating the HF and LF and then use the Front speaker terminals on the Yamaha to power the hpf or top end of the speakers and use a separate power amp plugged into the Front Pre outs of the Yamaha to power the lpf or bottom end. So essentially I am using 2 power amps to drive the speakers.

[almikel]

25 minutes ago, Scolburn79 said:

I want to remove the strips on the back of the front speakers separating the HF and LF and then use the Front speaker terminals on the Yamaha to power the hpf or top end of the speakers and use a separate power amp plugged into the Front Pre outs of the Yamaha to power the lpf or bottom end. So essentially I am using 2 power amps to drive the speakers.

I understand what you're trying to do, I just think a better idea is using the same additional power amp you're planning to purchase driven from the yammie pre-outs to power your main speakers (both drivers using the existing passive crossovers), and if you want you can swap the "strips" for short bits of decent speaker wire with appropriate connectors - plenty of people here on SNA reckon short pieces of speaker wire is superior to the "strips".

 

38 minutes ago, Scolburn79 said:

So essentially I am using 2 power amps to drive the speakers.

understood - what if those 2 amps have different gains? how will you manage level setting?

52 minutes ago, robmid said:

I have bi-amped a pair of Hypex amps. One dedicated to bass and the other to an ESL panel using the same passive bass and treble crossovers as I previously used with a single amp. However, I have added a 20 turn trimpot between the StereoCoffee LDR preamp output and bass Hypex inputs on the more sensitive bass speaker which allows me to trim bass/treble balance with precision.

you would need to include something like @robmid uses above to manage gain differences between amps.

 

To simplify the setup I'm suggesting using the additional amp to drive your main speakers - significantly reducing load on the yammie, but without introducing issues with level setting across amps.

 

I run a fully active setup - all crossover duties are done prior to power amps - none of my speakers/drivers have internal passive crossovers - level setting across amps is part of the setup for active crossover systems - but shouldn't be required in your passive crossover setup.

 

Doing it the way you suggest brings a bunch of issues with minimal benefit IMO.

 

cheers

Mike

[almikel]

 

1 hour ago, robmid said:

I have bi-amped a pair of Hypex amps. One dedicated to bass and the other to an ESL panel using the same passive bass and treble crossovers as I previously used with a single amp. However, I have added a 20 turn trimpot between the StereoCoffee LDR preamp output and bass Hypex inputs on the more sensitive bass speaker which allows me to trim bass/treble balance with precision.

 

The result is very seamless.

Rod Elliot calls this "Passive Bi Amping" or "Active Bi Wiring"

You have the cost of an additional amp, and all the downsides of high level passive crossovers.

2 hours ago, robmid said:

using the same passive bass and treble crossovers as I previously used with a single amp

Designing/implementing good passive crossovers is really hard to do - especially 3 way or more.

Most commercial speakers with passive crossovers compromise somewhere (eg bipolar electrolytic caps, iron cored inductors, or no driver impedance compensation).

 

I have a strong bias towards active crossovers - I won't pollute this thread with details why, beyond adding another link to Rod Elliot's site on the challenges in designing a good passive crossover:

https://sound-au.com/lr-passive.htm

 

@Scolburn79 - forget passive bi amping/active bi wiring - just use the additional amp to drive your main speakers.

 

cheers

Mike

[robmid]

I agree totally. Active implementation and a second amp would be the right solution this project.

 

I know passive crossovers are an art and spent almost 12 months of tweaking before the ESL's came close to integrating with my mid/woofers. This didn't happen until I added the bass attenuation.

 

When I built my integrated Hybrid ESL/Hypex/StereoCoffee amp I did install a pair of two way active analog crossovers but auditions with my system, which exploits micro detail, didn't have the soul of the passive first order crossover which I was intending to replace.

 

Many other DIY ESL owners have found the same problem and some have reverted from active to passive crossovers.

 

Cheers,

Rob

[almikel]

23 minutes ago, robmid said:

Active implementation and a second amp would be the right solution this project.

not really what I was suggesting - just a second amp driving the mains with their existing crossover is where I was going...an active solution would be a different journey

[AudioGeek]

The problem with the Yamaha avr's (have not tried their dedicated pre's) is that the preouts are almost an after thought and sound horrible - on mine the output impedance was 1200ohms and less than 2V.

[Scolburn79]

Ok, so maybe what I might do then is get the Emotiva Bas X 300 amp (2 x 150Wrms) and power the fronts only. If a second Emotiva Bas X 300 comes up for sale cheap then I could buy that one and then use RCA "Y" splitters and use one amp on the Front Right Channel and use the other amp on the Front Left Channel and pump one side of the AMP into the HPF and the other into the LPF. This would sort out the gain issues into the same speaker and then I am pumping 300w into these speakers.

[almikel]

3 hours ago, Scolburn79 said:

Ok, so maybe what I might do then is get the Emotiva Bas X 300 amp (2 x 150Wrms) and power the fronts only.

you might be chasing your tail based on @AudioGeek's post

18 hours ago, AudioGeek said:

The problem with the Yamaha avr's (have not tried their dedicated pre's) is that the preouts are almost an after thought and sound horrible - on mine the output impedance was 1200ohms and less than 2V.

 

[Scolburn79]

This is the specs I could find on the pre outs of the Yamaha. Maybe he was talking of the RX V range and not the RX A range???

[Guest thathifiguy]

The use of a single external power amp may be of some benefit, but this;

 

9 hours ago, Scolburn79 said:

If a second Emotiva Bas X 300 comes up for sale cheap then I could buy that one and then use RCA "Y" splitters and use one amp on the Front Right Channel and use the other amp on the Front Left Channel and pump one side of the AMP into the HPF and the other into the LPF. This would sort out the gain issues into the same speaker and then I am pumping 300w into these speakers.

I think is a pointless endeavour.

 

Edit - This is not how passive bi-amping works. The power output will not double.

Edited August 4, 2019 by thathifiguy

[AudioGeek]

Have a look around some of the AV forums. I dont think anyone has been too impressed with the preouts on the Yamaha AVR's.

 

Do you havre another power amp you could try on it?

 

Your speakers are not that hard to drive - what are you hoping to achieve?

 

Have a look at March audio - you would get a lot more amp for the same money.

[Scolburn79]

I am struggling to see why this wouldn't work. If I get a power amplifier that say has a power output of 200w or 300w per channel. If you don't remove the binding strips on the back of the tower speaker then you are feeding both high and low pass filters/crossovers. From my understanding, you are wasting some power by the high pass filtering out what it can'tuse and vice versa with the low pass filter. So wouldn't it be better to put 150w in to the HPF and 150w into the LPF. I know it would probably be better to put more into the LPF as it uses more power but it they are both getting equal power. I don't think the Emotiva has a gain setting on it either so 2 of the same model should be right???

[Scolburn79]

3 minutes ago, AudioGeek said:

Have a look around some of the AV forums. I dont think anyone has been too impressed with the preouts on the Yamaha AVR's.

 

Do you havre another power amp you could try on it?

 

Your speakers are not that hard to drive - what are you hoping to achieve?

 

Have a look at March audio - you would get a lot more amp for the same money.

I just feel my fronts would come more alive with a bit more power through them. I could pick up a Emotiva A300 for around $450 hence the reason for this. If I found another one for the same price then I could either do Horizontal Bi Amping or Vertical B Amping with them

[sir sanders zingmore]

9 minutes ago, Scolburn79 said:

So wouldn't it be better to put 150w in to the HPF and 150w into the LPF.

In general, you are only are putting as much power in as you need for the volume you listen at. So you almost certainly aren’t putting 150w into the speakers. 

Also, passive bi-amping with two amps of 150 w don’t add up to 300w 

[AudioGeek]

Ok, understand. Is this for movies or music?

I wonder if higher quality efficient speakers will make more of a diffetence than additional amps.

[Scolburn79]

3 minutes ago, AudioGeek said:

Ok, understand. Is this for movies or music?

I wonder if higher quality efficient speakers will make more of a diffetence than additional amps.

It is for both. The speakers to me are perfect. I understand that the Yamaha 3070 says it puts out 165w per channel. But that is only in 2 channel mode I believe. So I think it is only putting out maybe 110w per channel with all 9 channels going. So I'm thinking a more powerful amp will bring them alive so much more. A more powerful amp is cheaper than buying new speakers. Looks like I might need to save up for a better amp layout then. The March Audio ones do look good though and don't break the bank.

[gibbo68]

Hi, I have a Yamaha Rxv3085 running 7.1.2 subsonic speakers with front and centre powered by Emotiva A5175, fronts biwired using 4 of the power amps channels from the front channel preouts of the 3085. I originally had Emotiva A300 , but had some trouble with a faulty transistor so swapped it for the A5175. There was an improvement in sound with the addition of the A300 and a further improvement with the upgrade to the A5175, even the Mrs was impressed.

[Neilsy]

So long as you have access within the AVR to adjust the gain attenuation to LF and HF this should in theory be fine.
Most HF's are a lot more efficient than LF drivers.

I would put the higher (and cleaner) watt amp on the LF. But you also don't want the HF's to use, say, the Yamaha portion as your distortion ratio to volume will not be equal.
Better to stick your L and R speakers, as a whole, on one better amp channel each than go for marginally larger bi-amping.

+1 to everything everyone else has said.

[Scolburn79]

Ok cool. I actually have my eye on a 5 x 250w rotel amp as we speak. I am just not sure, if I get this amp, to hook up the AMP as L,R, Centre and surrounds or just go L,R and Centre and let the Yamaha do the rest of my 7.1.2 setup...

[Neilsy]

Solid plan.
You could put your 2x height channels on that same 5 channel Rotel as the L, C, R.
Then use the Yamaha for the 4 remaining surround channels.
As it's likely the height channels would consume the least load, so your Rotel is mainly dedicated to opening up your front 3 speakers.

Ok cool. I actually have my eye on a 5 x 250w rotel amp as we speak. I am just not sure, if I get this amp, to hook up the AMP as L,R, Centre and surrounds or just go L,R and Centre and let the Yamaha do the rest of my 7.1.2 setup...