I hope we're talking about active crossovers here. Driving a passive crossover with 2x amp channels is pointless.
Anyway, I'd always use vertical bi-amping. ie, each 2-ch amplifier is running one channel of LF and one channel of HF.
The advantages are:
- Means you can have short speaker cables
- Spreads the power requirements evenly across the amplifiers. ie, one isn't working hard producing LF and the other barely trying
- Probable reduction in crosstalk.
In practice, the 2nd and 3rd points aren't particularly applicable to home HiFi. Crosstalk performance should be good enough, and the amplifiers are rarely pushed hard.
Chris
Anyway, I'd always use vertical bi-amping. ie, each 2-ch amplifier is running one channel of LF and one channel of HF.
The advantages are:
- Means you can have short speaker cables
- Spreads the power requirements evenly across the amplifiers. ie, one isn't working hard producing LF and the other barely trying
- Probable reduction in crosstalk.
In practice, the 2nd and 3rd points aren't particularly applicable to home HiFi. Crosstalk performance should be good enough, and the amplifiers are rarely pushed hard.
Chris
Hi chris661. Yes I'm actually talking about bi-amping 2-way speakers with in-built crossover and I have to disagree that it is pointless because:
a) Plenty of bi-wireable/bi-ampable speakers are out there;
b) There is sonic improvement in bi-amping so why be dismissive?
c) This improvement exists regardless whether crossover is passive or active because the kinds of distortion they are subject to are common to both ie crosstalk, channel separation, IMD, phase distortion, etc.
In my passive crossover system, the horizontal high low bi-amplification, ie highs sharing one amp and lows sharing separate amp, sounded much better top to bottom than vertical mono mono bi-amp and this is something I totally did not expect. It is almost counter intuitive but my ears can't lie.
a) Plenty of bi-wireable/bi-ampable speakers are out there;
b) There is sonic improvement in bi-amping so why be dismissive?
c) This improvement exists regardless whether crossover is passive or active because the kinds of distortion they are subject to are common to both ie crosstalk, channel separation, IMD, phase distortion, etc.
In my passive crossover system, the horizontal high low bi-amplification, ie highs sharing one amp and lows sharing separate amp, sounded much better top to bottom than vertical mono mono bi-amp and this is something I totally did not expect. It is almost counter intuitive but my ears can't lie.
I think bi-wiring is useless but having one amp for the tweeter and one amp for the woofer would make some sonic differences.
Of course active crossover is going to be even better/best.
Often point of biamping is to compensate for different efficiencies between top and bottom. So you need to adjust different volume to woofers vs top. Having one stereo amp dedicated to woofers and one for the top seems logical.
Bi-amping with a passive crossover is not pointless. You are still getting the advantage of lessening the difficulty of the load on the amp, which is good for sound quality. Your high-frequency amp won't be loaded down by pumping current to the bass driver, and its power supply won't be drooping and fluctuating with each bass note.
a) - So?
b) - Have you tested this? I have. No measurable difference.
c) - The huge advantage in bi-amping lies with active crossovers, and having the drivers connected direct to the amplifiers. Leaving the passive crossover in place kills that advantage entirely.
With a reasonably capable amplifier (ie, one which can supply bass and treble at the same time) I maintain there's no benefit to bi-amping a passive crossover.
Chris
Gee Mr. Pass, I sure would have guessed you would suggest a class A FET on the top.
Comments on various posts:
Wow, I have been out of the loop for a while just listening to music. I see the bi-wire scam is still alive and well. Do they sell foil triangles for the doors too? Folks still using $5000 amps on $12 tweeters?
If you think distributing the load on amps is audible, I suggest you have really poor amps with insufficient power supplies or are just reaching for reasoning devoid of audible differences.
No fast rules for which config has the best cabling as it depends entirely on your installation. A few feet is over-rated anyway.
I sold off my three Parasound 1200's and active crossovers. I now run just my own 60W MOSFET to passive crossover 2-ways, active sum/crossover to a powered sub. Guess what? No determinable difference in quality at listening levels I ever could tolerate. No more power sequencer, no more complex electronic crossover, no active eq needed. Just really nice music. I found I can eq for the room with passive crossovers easier than going electronic. Not a fan of DSP but I guess that changes the ease question. I'm an old guy and do analog. ( Actually, I am a retried computer scientist)
This is the only possible reason I can see for biamping speakers with passive crossover networks. You do, however, need to be able to match the gains on the woofer and tweeter amplifiers. This is why vertical biamping is easier - it matches the gains, but it doesn't allow amplifier tonal matching to the top and bottom.
Last edited:
If the amps are SE, Pre-EQ (active crossover) and post-EQ (passive crossover) should make considerable difference in H2 phase even if the both EQ behave exactly the same. I can't say which is better, but this is something we may want to concern.
I don't know why no one is talking about how the crossover influences H2 phase, and many speakers have flipped phase tweeter.
I don't know why no one is talking about how the crossover influences H2 phase, and many speakers have flipped phase tweeter.
Of course some speakers WITH PASSIVE CROSSOVRS have inverted phase tweeters as they are actually in phase with the network connected. When bi-amping, one would only have a large blocking cap on the tweeter and no crossover causing need for phase correction. Of course, if your amp is inverting, just swap the leads. ( Not going down the absolute phase rat hole which is actually indeterminable anyway)
Bi-amping correctly also means you need to deal with the driver offset in the low power stages which is not part of most analog active crossover designs. With DSP, you could and could actually deal with time, not phase.
If you are worried about the "character" of the amps not matching, get some better amps. Mr. Pass can help you with that. Amplifiers should amplify, not add character, which is a polite name for distortion. I rely on the musician and producer to decide what distortion to add where, be it an old Tube Fender, AKG tube mic or some Royer ribbon. They can decide what brand strings they like on their guitar, brand of cymbal or drum skin. My reproduction system is to reproduce. Sort of an exception is for cheapo speakers with breakup issues, better to choose an amp with dominant pole compensation rather than transient miller. Good speakers, then TM for me all the way! As an example, an old Rotel will sound better on cheap speakers than a Parasound, Move up from $25 tweeters to $100 tweeters, and wow, does the Parasound sound better. The engineers knew what they were doing and why.
I fell for all that magic hub-bub when I was younger. Sells a lot of hardware. Then I figured out the cheapest Radio Shack receiver was better than the best speakers made, so I focused on where the real issues are.
I finally found a forum where psycho-acoustics are discussed. This is actually relevant to this discussion of how to connect bi-amps. There is a principal, sorry I do not remember the gentleman's name, if you have an idea you think will be better, you will hear it better to your ears unless it is really terrible. Actually a reason to support DIY as regardless of the actual results, you will like it more and that is what matters!
WOW, we just had a small earthquake.
Bi-amping correctly also means you need to deal with the driver offset in the low power stages which is not part of most analog active crossover designs. With DSP, you could and could actually deal with time, not phase.
If you are worried about the "character" of the amps not matching, get some better amps. Mr. Pass can help you with that.
Amplifiers should amplify, not add character, which is a polite name for distortion. I rely on the musician and producer to decide what distortion to add where, be it an old Tube Fender, AKG tube mic or some Royer ribbon. They can decide what brand strings they like on their guitar, brand of cymbal or drum skin. My reproduction system is to reproduce. Sort of an exception is for cheapo speakers with breakup issues, better to choose an amp with dominant pole compensation rather than transient miller. Good speakers, then TM for me all the way! As an example, an old Rotel will sound better on cheap speakers than a Parasound, Move up from $25 tweeters to $100 tweeters, and wow, does the Parasound sound better. The engineers knew what they were doing and why. I fell for all that magic hub-bub when I was younger. Sells a lot of hardware. Then I figured out the cheapest Radio Shack receiver was better than the best speakers made, so I focused on where the real issues are.
I finally found a forum where psycho-acoustics are discussed. This is actually relevant to this discussion of how to connect bi-amps. There is a principal, sorry I do not remember the gentleman's name, if you have an idea you think will be better, you will hear it better to your ears unless it is really terrible. Actually a reason to support DIY as regardless of the actual results, you will like it more and that is what matters!
WOW, we just had a small earthquake.
Years ago, I owned a pair of Stan Warren (Superphon, PS Audio fame) Superphon amps and matching preamp.
The amps were 60 watt per channel, but could be switched to mono, at 120 watts which is how I intended to run them.
In mono, the amps sounded "wirey" and thin when compared to the stereo setting. They were also a bit less stable in mono which resulted in replaced outputs a couple of times. So as experiment I used a pair of Y interconnects from each channel of the preamp to each amp, so one channel went to bass one to tweeter. Internal cross over of speaker in place. (Obviously, these speakers had dual sets of binding posts.)
This solved the problem, sweeter sound of stereo amps, with each amps capability now dumped into each speaker.
Power wise, the speakers had more power available than a single amp could provide, plus the advantage of mono block type separation of channels.
Yes it sounded better...why wouldn't it? More power plus the separation advantages of mono blocks as well.
It's not the same as horizontal bi amping with active cross over, and not implemented for the same reasons.
If there were no improvement, then I guess there is no advantage to mono blocks or dual mono over stereo 2 channel.....that said, I don't run my First Watt clones like this, just remembering those old amps....
Russellc
The amps were 60 watt per channel, but could be switched to mono, at 120 watts which is how I intended to run them.
In mono, the amps sounded "wirey" and thin when compared to the stereo setting. They were also a bit less stable in mono which resulted in replaced outputs a couple of times. So as experiment I used a pair of Y interconnects from each channel of the preamp to each amp, so one channel went to bass one to tweeter. Internal cross over of speaker in place. (Obviously, these speakers had dual sets of binding posts.)
This solved the problem, sweeter sound of stereo amps, with each amps capability now dumped into each speaker.
Power wise, the speakers had more power available than a single amp could provide, plus the advantage of mono block type separation of channels.
Yes it sounded better...why wouldn't it? More power plus the separation advantages of mono blocks as well.
It's not the same as horizontal bi amping with active cross over, and not implemented for the same reasons.
If there were no improvement, then I guess there is no advantage to mono blocks or dual mono over stereo 2 channel.....that said, I don't run my First Watt clones like this, just remembering those old amps....
Russellc
Last edited:
So vertical bi-amping on passive crossovers did it for you. I'm happy for you and not surprised as I've tried it myself. But I also tried it horizontally and got even better results. Did you try horizontal as well?
I started this thread because I was expecting vertical to do better but actually didn't and I'm trying to figure out the reason/s why. In my case, I'm using 2 hybrid integrated amplifiers with tone controls (same maker) so that means the volume is the 3rd knob I get to tune for each spectrum!
I'm amazed at the results I got. To think that my 2-way speakers is my first attempt at DIY, a journey that kind of happened because of spending more time at home due to pandemic.
I started this thread because I was expecting vertical to do better but actually didn't and I'm trying to figure out the reason/s why. In my case, I'm using 2 hybrid integrated amplifiers with tone controls (same maker) so that means the volume is the 3rd knob I get to tune for each spectrum!
I'm amazed at the results I got. To think that my 2-way speakers is my first attempt at DIY, a journey that kind of happened because of spending more time at home due to pandemic.
Been there done that (on passive not active) @Chris that is why I started this thread to begin with. I got amazing results in horizontal as compared to vertical and trying to figure out why. I'm actually planning to try active bi-amping next so hopefully I get to compare them.
Bi-amping passives is definitely not pointless based on my actual experience. I learned a lot and very happy with results I got.
Yes @scottjoplin, taking measurements would be logical if you have the instruments and the technical skills. I have neither.
I rely mainly on my ears, research and counsel from experts for answers. I'm in this forum hoping for experts to tell me whether my finding is to be expected or not, and why. When I say experts I mean electronics engineers at the minimum.
I rely mainly on my ears, research and counsel from experts for answers. I'm in this forum hoping for experts to tell me whether my finding is to be expected or not, and why. When I say experts I mean electronics engineers at the minimum.
Measurements have their place, but when it sounds better, it just does. I have never split the right and left into separate amps (or full dual mono) that it didnt make an immediate improvement.
In my case back then, horizontal bi amping wouldn't have that advantage. Perhaps horizontal biamping has more utility when done actively? I never went down that road as I didn't desire whatever benefit it would yield, I was more interested in the "mono block" advantage of each channel having its own amp, and I was still dumping the amps power into one speaker.
Again, I don't do this with my First Watt clones, with them it is either mono blocks or dual mono from here on out for my First Watt clone builds.
Russellc
In my case back then, horizontal bi amping wouldn't have that advantage. Perhaps horizontal biamping has more utility when done actively? I never went down that road as I didn't desire whatever benefit it would yield, I was more interested in the "mono block" advantage of each channel having its own amp, and I was still dumping the amps power into one speaker.
Again, I don't do this with my First Watt clones, with them it is either mono blocks or dual mono from here on out for my First Watt clone builds.
Russellc
Last edited:
That was exactly my thinking. I first tried vertical like you did and that made a big improvement then I skeptically tried horizontal but I was in for a surprise. I heard a bigger improvement from top to bottom.
Since the amps I'm using are hybrid integrateds with tone controls I have 3 knobs, volume, bass and treble, at my disposal for tuning each spectrum ie highs and lows. An engineer friend of mine said one advantage of horizontal bi-amping is in lowering if not eliminating IMD. From my listening it also seems to better preserve phase information but I'm not an engineer so I'm just guessing.
Since the amps I'm using are hybrid integrateds with tone controls I have 3 knobs, volume, bass and treble, at my disposal for tuning each spectrum ie highs and lows. An engineer friend of mine said one advantage of horizontal bi-amping is in lowering if not eliminating IMD. From my listening it also seems to better preserve phase information but I'm not an engineer so I'm just guessing.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.