The Difference Between Bi-amping and Bi-wiring

Swerd

Swerd

Audioholic Spartan
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5,170 11 6
My earlier comments were written assuming you had less knowledge about electronics than I now understand you do have. I guessed wrong and wasn't trying to slight you.
What about the voltage limit of the amp? E.g.: there is -+20V PSU. If you have an 50Hz sine wave with the maximum output amplitude (20Vpp) and you want to add a 10kHz 2Vpp signal on it, the 10kHz signal will be cut and limited because of the supply voltage limit. If you filter out the high amplitude 50Hz before the amp, you will not have this problem on high frequencies. So in this case it makes sense to use the filter before the amp. What do you think?
You are worrying about voltage clipping in very small amplifiers while ignoring the larger problem you have with mid grade speakers (a charitable description of some MA Bronze speakers I once heard years ago). They have what is likely to be much higher distortion and poorer sound quality than any improvements you might obtain by the various contortions of bi-amping with small class A amps.

You will have greater improvements to sound quality if you focus on acoustic waves coming from speakers than if you focus on electronic waves going into them.
 
B

Barnabas Puskas

Audiophyte
Ratings
1
The idea that bi-amping lowers IM distortion (intermodulation),or improves sound by separating a woofer's back EMF from the tweeter, is old and has been debunked.
Removing or disconnecting your speakers' crossover networks will also void the warranty.
Depending on how these additional filters are designed, this, at best, will accomplish nothing. At worst, these additional filters will have a negative impact on the function of the speakers' crossover filters. This is a solution for a non-existent problem.
Thank you for your reply. Can you give me an explanation for the concept that lower bandwidth why not cause less intermodulation? When I was young it was teached that less spectrum lines have less intermodulation combination. E.g.: If you have two sine waves only (2 spectrum lines) you can have result A+B and A-B as a combination frequency. If you have 3 lines, you can have A+B, A+C, C+A, A+B+C, A+B-C,... much more. In narrower bandwidth you have less spectrum lines, which produce less combination frequency. This is the same in DWDM technology in optics (I am a DWDM specialist). You can give technical answer. I am an electrical engineer. :)

Regarding the last two parts I agree. Thanks again!
 
Swerd

Swerd

Audioholic Spartan
Ratings
5,170 11 6
Thank you for your reply. Can you give me an explanation for the concept that lower bandwidth why not cause less intermodulation?
I can only repeat what I said before. Sound quality is more about acoustics and the wave behavior of the rather long wavelengths involved with 20 to 20,000 Hz, compared to the much shorter wavelengths involved in other aspects of electronics, or optics. I'm not an EE, so I'll stop and wait for one of several EEs who frequent here to take the ball. @PENG, where are you?

I do recognize and appreciate your straight forward and polite posts on the highly controversial subject of bi-amping :). Many times we are on the receiving end of heated attacks from hard core Cool-Aid imbibers, or mock attacks from trolls. You clearly do not seem to be one of them.
 
B

Barnabas Puskas

Audiophyte
Ratings
1
My earlier comments were written assuming you had less knowledge about electronics than I now understand you do have. I guessed wrong and wasn't trying to slight you.
You are worrying about voltage clipping in very small amplifiers while ignoring the larger problem you have with mid grade speakers (a charitable description of some MA Bronze speakers I once heard years ago). They have what is likely to be much higher distortion and poorer sound quality than any improvements you might obtain by the various contortions of bi-amping with small class A amps.

You will have greater improvements to sound quality if you focus on acoustic waves coming from speakers than if you focus on electronic waves going into them.
No problem. I did not know either if electrical engineers are here or just golden-ear guys. :) But I am happy that I can really have discussion here with technical guys. Yes you got the true that probably not the amplifier is the weakest part of my system. I tried these speakers with A/B class amp (e.g.: Texas integrated gainclone),but it sounded differently (worse) with that. Maybe I should try with another type of A/B. Anyway Bronze 6 is not bad. Ok, not high-end but now they use the old Silver drivers in Bronze, which was a significant improvement in this price category. Anyway the biggest problematic part in my system is the source of the music. It is hard to find a dynamic compression free music nowadays thanks to the loudness war. But this is another topic.
 
Swerd

Swerd

Audioholic Spartan
Ratings
5,170 11 6
No problem. I did not know either if electrical engineers are here or just golden-ear guys. :) But I am happy that I can really have discussion here with technical guys.
There are several regulars who post here who are EEs or at least have enough background to talk like an EE. I am smart enough to know when to keep my mouth shut :D.

We tend to frown on 'golden ears' or those who cannot back up their extreme opinions with some supporting evidence.
Yes you got the true that probably not the amplifier is the weakest part of my system. I tried these speakers with A/B class amp (e.g.: Texas integrated gainclone),but it sounded differently (worse) with that. Maybe I should try with another type of A/B.
There are at least one or two here who have built their own amps or amp kits.
Anyway Bronze 6 is not bad. Ok, not high-end but now they use the old Silver drivers in Bronze, which was a significant improvement in this price category. Anyway the biggest problematic part in my system is the source of the music. It is hard to find a dynamic compression free music nowadays thanks to the loudness war. But this is another topic.
True, I agree.

If I have any expertise at all, its about speaker designs and what actually produces better sound quality. Or what features produce audible problems. More often than not, it's poor crossover design. I can think of several commercial speakers which allow too much woofer break up noise to get by. If I remember correctly from more than 10 years ago, the Monitor Audio Silver 2-way tower speakers I heard suffered from an aggressively forward sound. At first it sounded like the speakers added great detail. But it led to an irritating edge in the upper mid range. I never listened longer to know if that led to the dreaded 'listener's fatigue'. It might have been due to inadequately filtered high frequency resonance or noise coming from the metal alloy woofers. As you can see, I'm a speaker guy, not an amp guy :D.
 
P

PENG

Audioholic Overlord
Ratings
5,748 9 1
Nice analogy and it is true if we speak about power. Of course the amplifier cannot push any power on the high impedance part of the load (that frequency range which is out of the woofer / tweeter range). But a question? What about the voltage limit of the amp? E.g.: there is -+20V PSU. If you have an 50Hz sine wave with the maximum output amplitude (20Vpp) and you want to add a 10kHz 2Vpp signal on it, the 10kHz signal will be cut and limited because of the supply voltage limit. If you filter out the high amplitude 50Hz before the amp, you will not have this problem on high frequencies. So in this case it makes sense to use the filter before the amp. What do you think?
Note: I use an own built class A amp with limited power.
That seems right in theory. I am not sure if you will end up with a net gain in sound quality because now you are introducing an active filter ahead of the power amp, and that itself could have negative effects depending on how it is done. I think overlapping the bands is a good idea conceptually. Sounds like a fun R&D project. The more typical response to this kind of questions don't seem to apply here because you are trying to biamp using a very low power amp to drive the tweeters and a beefier amp for the woofers.
 
TLS Guy

TLS Guy

Audioholic Slumlord
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7,742 16 25
Thanks for your useful answer. Yes, the other thing why I begun to think about biamping is the power sharing. At this moment I use a pure class A amplifier (a John Linsley Hood one) to drive this speakers, but it has quite a low output power (8-10W RMS max.) So I have two ways now:
- use biamping with 2 JLH amp / channel or one A/B class for LF and one pure class A for HF
- build a bigger amplifier: here the problem is that it is not easy to build high power class A amp because of the cooling and high power consumption problem
Note: I prefer class A only based on my good experience.
Then your answer if you insist on class A is a Quad current dumping amp. That is Peter Walkers brilliant invention.

The concept, is a class A/B amp, that actually does not have to be outstanding. This is the dumper. Then there is a very good class A amp that feeds a feed forward error correction. This gives pure class A performance. It can be shown mathematically and in practice that the performance is entirely the spec. of the class A amp.

These amps run very cool.



3 KW of class A audio power that powers my studio/AV room. That is a bank of seven Quad 909 power amps.
 
P

PENG

Audioholic Overlord
Ratings
5,748 9 1
I think the main advantage of bi-amping is not to amplify the whole spectrum reducing the intermodulate distorsion with this method.
I have to think about this, but on surface I doubt that is the case because instead of have all the IMD frequencies generated by one amplifier, you simply have them generated by two amplifiers in the bi-amp scenario. So any reduction in % IMD will depend on the qualities of the amp/amps, not on whether you use one amp or two/bi-amp. That is you still have the IMD for the full spectrum.

IMD is generally not a problem for good quality and relatively affordable amps made by reputable manufacturers.
 
P

PENG

Audioholic Overlord
Ratings
5,748 9 1
If I remember correctly from more than 10 years ago, the Monitor Audio Silver 2-way tower speakers I heard suffered from an aggressively forward sound. At first it sounded like the speakers added great detail. But it led to an irritating edge in the upper mid range. I never listened longer to know if that led to the dreaded 'listener's fatigue'. It might have been due to inadequately filtered high frequency resonance or noise coming from the metal alloy woofers. As you can see, I'm a speaker guy, not an amp guy :D.
Well then I guess not much has changed, I installed a 7.1 MA system based on the Silver 8 and the Marantz SR7009 about a year ago. My initial impression of their sound and my updated impression in a recent visit remain the same, that they are a little bright and overly forward. To give them some benefits of doubt though, that room is not particularly well damped and too big for the AVR. So I am sure there is room to improve, but they sound great to the owners so there is nothing I can do about it.:D
 
D

DigitalD

Audioholic Intern
Ratings
4
He is talking about back EMF into the amp. Not really an issue. Personally I do like passive bi-amping in some cases. Back in the day I used to biamp with my Denon 5805 for my front towers. That receiver had a ton of reserve and it helped to drive my towers better than the single amp connection. However, I could have achieved the same results simply using a higher power external amp in a single wire connection.
Would Bi-Amping my Klipsch RF7IIIs with an Outlaw Model 7000x receive any benefit? I feel like I am not getting much bass and I am upgrading from Polk Satellite speakers. Maybe the speakers aren’t broken in yet?
 
Irvrobinson

Irvrobinson

Audioholic Spartan
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Would Bi-Amping my Klipsch RF7IIIs with an Outlaw Model 7000x receive any benefit? I feel like I am not getting much bass and I am upgrading from Polk Satellite speakers. Maybe the speakers aren’t broken in yet?
Speaker break-in is a myth. With those speakers and an Outlaw 7000x it is unlikely you will receive any benefit all, unless you have a huge room and listen to very bass-heavy music at high volumes.
 
D

DigitalD

Audioholic Intern
Ratings
4
Speaker break-in is a myth. With those speakers and an Outlaw 7000x it is unlikely you will receive any benefit all, unless you have a huge room and listen to very bass-heavy music at high volumes.
So I basically need a higher powered amp to see a benefit/increased bass?
 
Irvrobinson

Irvrobinson

Audioholic Spartan
Ratings
3,005 10 12
So I basically need a higher powered amp to see a benefit/increased bass?
No. I don't believe a higher power amplifier will give you better bass. More likely you either need different placement of the RF7IIIs to mitigate so-called "suck-outs" in the listening seat frequency response, or you need to add one or more subwoofers, placed for smoothest bass response.
 

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