Biamping with 2 x identical amps, breakthrough

[Goldjazz]

I've been playing around with biamping my 4343's on and off for months. Ive tried several different amps, a jbl m552 x over and now a berringer one. I was never totally happy with the result, always felt like I gained some bass punch but lost some clarity. Tried inverting woffers etc due to the phase issue of 24db slope but nothing worked. I put it down to poor quality x overs.

Well everything changed last night. I got myself a second Perreaux amp. The first is a 6000b (300w) the second is basically identical a 6200b (270w).

I noticed an immediate improvement on previous biamp attempts. First impressions the 4343s sounded more alive, like they'd been given a shot of adrenalin. The highs are more vivid and the mid bass and lows are more punchy but everything is still clear and tight. Also imaging was better. Basically exactly what I was after.

I feel as though the amps are more balanced and allow the drivers to work together better.

I dont think its the extra power as ive tried a 600w crown with one of the perreauxs before with no good result. Also tried 130w sansui and 130 w accuphase and every combination of those amps above. I dont think its the phase issue with using a 24 db slope either as I tried all the permutations.

I think there's some really good matching or synergy (sorry I hate that word) that happens when you use two identical amps it just sounds balanced and right.

Ive also now got two bgw750c's which are lower power than the Perreaux's. I will try them too and see if this matching thing works with them too.

Is there any basis to this theory? Has anyone else found the same.

Cheers.

[BMWCCA]

I use a Crown PS400 and PS200 which seems to exhibit a similar synergy. Before that I used a Crown DC300A-II and D150A-II. Worked well. Actually I never considered bi-amping with mis-matched amps. :dont-know:

[Goldjazz]

Yeah ok so possibly staying in the same amp brand/family/model range but with different power output still yields the same results as in your case. I'm wondering if matching input sensitivity or gains or something is helping to produce a more balanced result.


I use a Crown PS400 and PS200 which seems to exhibit a similar synergy. Before that I used a Crown DC300A-II and D150A-II. Worked well. Actually I never considered bi-amping with mis-matched amps. :dont-know:

[Odd]

Amplifier for LF and HF work with program material of different frequencies.
Can not see the advantage of using the same brand.
I use a small power Pass Labs Class A on HF and a Crown Power Line Four on LF.
This combination sounds very good.

[loach71]

You have enough amps to go 4-way active. Why not bypass the passive crossovers altogether? I suggest you try a pair of RANE mono 4-way active crossovers. You might be pleasantly surprised. I like the Linkwitz-Riley filter topology used in the RANE product. They are another example of pro gear that is well suited to the home environment.

If you are worried about frying the smaller drivers in your 4343's, you might by a pair of BGW 250D amps for the 10" and compression driver and a BGW 150 for the tweeter. I have enjoyed great success with these amps and they are readily available on E-Pay.

I hope you enjoy experimenting with active filters!

[Goldjazz]

Yep thanks, and I am aware of many people that have good results with mixed amps also, which is why I'm a little puzzled. Perhaps the particular amps I had previous chosen match badly for some reasons whereas the ones you use match well. It's that question of what makes two amps work well together for biamping that I'm interested in.

I'm thinking that some amps differ a lot e.g. input impedence, input sensitivty, gain, or damping factor and it's just harder to find the sweet spot or some other crazy phase shift is going on because of these differences.


Amplifier for LF and HF work with program material of different frequencies.
Can not see the advantage of using the same brand.
I use a small power Pass Labs Class A on HF and a Crown Power Line Four on LF.
This combination sounds very good.

[Goldjazz]

Yeah I've been thinking about it, I need to recap and that would avoid this. But when I was trying to get my head around the passive network that's left when in biamp mode on the 4343 it seems that it's not just a frequency diving network but also doing other stuff which I don't understand yet (e.g. putting delays on certain drivers?) So I'm worried that it just won't sound right i I simply provide each driver with the correct freq band from a separate amp. I know you can put delays in and stuff externally but I think I need to understand what else that network does and how/why it does it....or I could just pull the trigger on those Rane's and start playing around :) Would love to do this if anyone has had any success, I may put a shout out on technical forum.




You have enough amps to go 4-way active. Why not bypass the passive crossovers altogether? I suggest you try a pair of RANE mono 4-way active crossovers. You might be pleasantly surprised. I like the Linkwitz-Riley filter topology used in the RANE product. They are another example of pro gear that is well suited to the home environment.

If you are worried about frying the smaller drivers in your 4343's, you might by a pair of BGW 250D amps for the 10" and compression driver and a BGW 150 for the tweeter. I have enjoyed great success with these amps and they are readily available on E-Pay.

I hope you enjoy experimenting with active filters!

[loach71]

Yeah I've been thinking about it, I need to recap and that would avoid this. But when I was trying to get my head around the passive network that's left when in biamp mode on the 4343 it seems that it's not just a frequency diving network but also doing other stuff which I don't understand yet (e.g. putting delays on certain drivers?) So I'm worried that it just won't sound right i I simply provide each driver with the correct freq band from a separate amp. I know you can put delays in and stuff externally but I think I need to understand what else that network does and how/why it does it....or I could just pull the trigger on those Rane's and start playing around :) Would love to do this if anyone has had any success, I may put a shout out on technical forum.

There are many 4th order 4-way active crossovers that incorporate all-pass functions for phase / time delay correction. The RANE gear is of very high quality without the snobbery of "audiophile" equipment and its associated price inflation.

Once done, you can start experimenting with a calibrated mike and a spectrum analyzer such as Room EQ Wizard to see what is really occurring in your sonic environment.

drop me a PM if you want some help...

[badman]

So long as you're not faced with odd time constant or phasing issues (which shouldn't be the case in any decent amps), it's perfectly okay to mix and match amongst good amps. Of course, you then have potential issues with tonal balance etc, but that's what listening is for. Mismatched dynamic performance can also be an issue, so there are several watch-outs, but that's the way of things in general.

[Goldjazz]

Yeah this is tempting. My current active x over (behringer X pro) though pretty low end, is actually capable of 4-way mono. So I could give this a go one speaker. I have intented getting the mike an spectrum anlyzer anyway. Thanks for the offer of help, I will definitely give this a try.


There are many 4th order 4-way active crossovers that incorporate all-pass functions for phase / time delay correction. The RANE gear is of very high quality without the snobbery of "audiophile" equipment and its associated price inflation.

Once done, you can start experimenting with a calibrated mike and a spectrum analyzer such as Room EQ Wizard to see what is really occurring in your sonic environment.

drop me a PM if you want some help...

[Goldjazz]

Speakerdave, yeah I'm interested in understanding what that network is doing for those 3 drivers. Is it mainly EQ'ing to achieve a flat response?

Do you think it would be possible to achieve the same effect through quad amping with an analogue active x over, analysis of the freq response, EQ, and adjusting the gains. I have considered this path with the use of a quality 4-way x over such as an Accuphase f-25, thought the stock freq card options are a bit off for the upper drivers.

Yeah I've been thinking about this conundrum a bit. I definetley want to preserve the passive network untouched, my 43's are basically mint and I want to keep them that way. I was thinking if I did stick with biamping I would build a totally seperate external box probably one of the CC designs others have done here, and just disconnect the original passive network and keep it untouched inside.

ha I don't mind a bit of wildcatting myself, sounds like a nice play with that TAD driver. I am pretty fond of TAD exclusive gear. I've also heard of other's replacing the woofer with a Gauss(brand) 15" driver. I not too much of a JBL fanboy to not consider such things as long as I can always put everything back to factory condition in the end

[antoninus9]

There are many 4th order 4-way active crossovers that incorporate all-pass functions for phase / time delay correction. The RANE gear is of very high quality without the snobbery of "audiophile" equipment and its associated price inflation.

Once done, you can start experimenting with a calibrated mike and a spectrum analyzer such as Room EQ Wizard to see what is really occurring in your sonic environment.

drop me a PM if you want some help...

I agree, Rane is a great choice. I also agree that using two identical amplifiers seems to produce the best results. My guess is that this is related to input sensitivity, and dynamic power output.

[loach71]

I agree, Rane is a great choice. I also agree that using two identical amplifiers seems to produce the best results. My guess is that this is related to input sensitivity, and dynamic power output.

For the purpose of experimentation, a pair of Behringer CX3400s would be OK. That being said, the build quality and sonic performance of the Behringer products in no way reaches that of the RANE active crossovers.

In short, you get what you pay for.

[Goldjazz]

For the purpose of experimentation, a pair of Behringer CX3400s would be OK. That being said, the build quality and sonic performance of the Behringer products in no way reaches that of the RANE active crossovers.

In short, you get what you pay for.

Yeah I totally agree Behringer is not good. I just got it as I wanted to play around. Having said that, I am getting better results with the Behringer than the JBL M552 I have.

[audiomagnate]

I don't think "indenticalness" for lack of a better word, helps in itself at all. Why is it a good thing for a tweeter amp to be identical to a woofer amp? Not only does it not provide an inherent benefit, it's a huge waste of money. Amps best suited to the frequency range in which they are operating is a much better way to go. It's bad enough finding room for multiple amps, but then adding the requirement that they all have to have the same current delivery potential as the ones on the woofers, meaning they all have to be huge and use all sorts of electricity, is just wrong. It's nice when things match, but it makes zero sense in this situation.

[fpitas]

I'm in the "different amps" camp. I use a First Watt class A for the horns, which don't need much power but are very picky about crossover distortion, and a more conventional high-bias class AB Parasound A21 for the midbass drivers.

[loach71]

Yeah I totally agree Behringer is not good. I just got it as I wanted to play around. Having said that, I am getting better results with the Behringer than the JBL M552 I have.

I would buy another Behringer CX3404 for use in the short term. Also purchase a Berhringer calibration mike (condenser type) and a Behringer mike preamp with phantom power supply for the mike.

You are already considering recapping your passive crossover -- so that means you will be digging into the JBL box. When you have removed the drivers be sure to label the wires emanating from the passive crossover for when you possibly reassemble the passive crossover version of your speakers. With the crossover and drivers removed from the box, you will have the space for a temporary (and hopefully permanent) binding post bay for all four drivers that will allow direct connectivity to their respective preamp channel.

P. S. I suggest you search the board for the nomograph that lists suggested values for series protection capacitors to use with your compression driver and tweeter.

You will need a mike stand to place the Berhringer calibration mike close to your favorite listening position. The Behringer mike preamp goes between the calibration mike and the analog input port on your PCs sound card. Once you have installed and run Room EQ Wizard on your PC you will probably see the need for a good parametric equalizer or 1/3 octave graphic equalizer to help smooth out the eigentones in your listening environment.

[macaroonie]

64961

[loach71]

Great information Macaroonie...
You have earned a MacEwans' stout!

[Goldjazz]

Thanks for that info macaroonie, will come in handy

[Goldjazz]

Cheers, I think this is a good plan and I'm gonna give it a go. I actually opened up one of the cabinets last night (with a little help from a car jack to pop the sticky front baffle from within) and wired all the drivers individually, running the wires out one of the bass ports. I then carefully hooked up a mono quad amped single speaker, setting the crossover points as per the 4343b spec. Even with only a single speaker and all the levels adjusted by ear (and the lowish quality behringer x-over) I could hear an improvement. The biggest difference is the 2420 horn...much clearer to my ears. Another thing was more control over the 2405, and generally less hiss is the system. So stay tuned for this one I'll post a bit more on the quad ampoed setup when I get all the bits and have it full up and running.
I would buy another Behringer CX3404 for use in the short term. Also purchase a Berhringer calibration mike (condenser type) and a Behringer mike preamp with phantom power supply for the mike.You are already considering recapping your passive crossover -- so that means you will be digging into the JBL box. When you have removed the drivers be sure to label the wires emanating from the passive crossover for when you possibly reassemble the passive crossover version of your speakers. With the crossover and drivers removed from the box, you will have the space for a temporary (and hopefully permanent) binding post bay for all four drivers that will allow direct connectivity to their respective preamp channel.P. S. I suggest you search the board for the nomograph that lists suggested values for series protection capacitors to use with your compression driver and tweeter.You will need a mike stand to place the Berhringer calibration mike close to your favorite listening position. The Behringer mike preamp goes between the calibration mike and the analog input port on your PCs sound card. Once you have installed and run Room EQ Wizard on your PC you will probably see the need for a good parametric equalizer or 1/3 octave graphic equalizer to help smooth out the eigentones in your listening environment.

[Goldjazz]

Yeah honestly I'd probably do the same if I had a nice Class A amp . I'm Just saying I happened to have two of the same amps (my Perreauxs are basically Mosfet PA amps which run AB) and the result was suddenly better than previous attempts with different amps. I'm sure a nice Class A on the highs with a different AB amp down low sounds better than the two poorer quality (but matched) AB amps I'm running.


I'm in the "different amps" camp. I use a First Watt class A for the horns, which don't need much power but are very picky about crossover distortion, and a more conventional high-bias class AB Parasound A21 for the midbass drivers.

[loach71]

Yeah honestly I'd probably do the same if I had a nice Class A amp . I'm Just saying I happened to have two of the same amps (my Perreauxs are basically Mosfet PA amps which run AB) and the result was suddenly better than previous attempts with different amps. I'm sure a nice Class A on the highs with a different AB amp down low sounds better than the two poorer quality (but matched) AB amps I'm running.


Im not so sure that you would hear a HUGE difference in the sonic quality between a well designed / built Class A amplifier and a well designed / built Class AB amplifier. The audiophile world is so full of marketing BS that the only test of any significance is that of critical listening in a controlled environment. The marketing hucksters:barf: have made "specsmanship" the de-facto strategy of the world of audio -- much to the pain of the consumer.

You own some very nice amps -- I would keep them and enjoy your upcoming exploration into the world of active crossovers, room equalization, and real-time spectrum analysis.

:bouncy:Have fun with your active 4 way system.:bouncy:

[Goldjazz]

Thanks Loach. I should be going to work right now but I can't pull myself away from listening to this single quad amped speaker. The depth of detail going on is pretty crazy, can't wait to hook up the other one and really dial them in with the eq etc.

[audiomagnate]

Thanks Loach. I should be going to work right now but I can't pull myself away from listening to this single quad amped speaker. The depth of detail going on is pretty crazy, can't wait to hook up the other one and really dial them in with the eq etc.

I don't use blocking caps (yeah I ride bareback) because they change the sound in my experience. IMO going active one speaker at a time is the way to go. The active speaker should be adjusted to sound as close to the original passive as possible, and then those settings cloned for the second speaker.

[fpitas]

For home use, one of the main reasons for the horn coupling cap is to high pass amplifier turn-on and turn-off thump. What would be a minor thump to a direct radiator can mean crashing the diaphragm into the pole piece for a horn driver. If you're lucky enough to have a "thumpless" amp, the other considerations are bad/loose cables and connectors, turn-on and -off thump at upstream components like preamps etc.

[Hoerninger]

... high pass amplifier turn-on and turn-off thump.


... they change the sound in my experience.
Consider charge coupling the caps.
___________
Peter

[loach71]

I don't use blocking caps (yeah I ride bareback) because they change the sound in my experience. IMO going active one speaker at a time is the way to go. The active speaker should be adjusted to sound as close to the original passive as possible, and then those settings cloned for the second speaker.

That is a good strategy to use as a starting point.

[Goldjazz]

Ok. This is a good idea. I haven't got the second speaker active yet so this will work. Are you saying disconnect all the drivers from the second speaker except the mirror of the one im trying to setup on the first speaker and play the second speaker thru its passive network with just one driver runing?




I don't use blocking caps (yeah I ride bareback) because they change the sound in my experience. IMO going active one speaker at a time is the way to go. The active speaker should be adjusted to sound as close to the original passive as possible, and then those settings cloned for the second speaker.

[Goldjazz]

Yeah my system thumps. I try to turn everything down first and turn on and off in a certain sequence but it does still thump a bit. QUOTE=fpitas;373698]For home use, one of the main reasons for the horn coupling cap is to high pass amplifier turn-on and turn-off thump. What would be a minor thump to a direct radiator can mean crashing the diaphragm into the pole piece for a horn driver. If you're lucky enough to have a "thumpless" amp, the other considerations are bad/loose cables and connectors, turn-on and -off thump at upstream components like preamps etc.[/QUOTE]

[Goldjazz]

Thanks I haven't done this before but I guess its easy enough to try. I don't know whether the horn sounds so much better now beacuse the caps in my passive network have drifted or if it just doesnt like caps in front of it as others have suggested. But perhaps a fresh cap with the added benefits of CC would preserve the clarity but protect
________
Peter[/QUOTE]

[loach71]

I don't use blocking caps (yeah I ride bareback) because they change the sound in my experience. IMO going active one speaker at a time is the way to go. The active speaker should be adjusted to sound as close to the original passive as possible, and then those settings cloned for the second speaker.

Shouldn't we call them prophylactic capacitors? ;)

[audiomagnate]

Shouldn't we call them prophylactic capacitors? ;)

Good one!

[SEAWOLF97]

Shouldn't we call them prophylactic capacitors? ;)

do you bi-amp your F's & A's :dont-know:

[Ian Mackenzie]

If you search for 4343 upgrade I did a lot on crossover upgrades and the pros and cons of bi am ping.

Essentially the network was based on the 2121 , the 2420 old aluminium diaphragm and the 2405.

The drivers are fairly aggressive in that the 2121 has noticeable edge in its break up mode, the 2420 fades above 7000 and the 2405 is bought in hot to recover the detail.

There is some benefit in using more contemporary crossover capacitors however the best favour you can do is bypass the biamp switches this places contact resistance and prevailing insertion losses in the signal oath. There are post on what to do if you care to look around.

Beyond that the 2421 with the alumina diamond diaphragm is better.

The 4344 was the work of Greg Timbers and was a refinement in drivers and the network over the 4340 and 4343/b

As the active crossovers we found the Passlabs xvr1 was an audible improvement over the JBL and other pro units.

JBL did a great unit for the XP series but is NLA.

I understand Greg had used them and the Pass labs.

Pass now had have a great Firstwatt model B4 that is stunningly good, alternatively look for the Bryston unit.

The distinction is these are both discrete and operate in class A, this transforms the HiFi element into what the Japanese regard as a one of the best loudspeakers of all time.

In the Jazz bars in Tokyo the 4343 has a Cult status. I have seen Passlabs Aleph 2 pure class A power amps driving the 4343s in a bar there and the sound was really impressive.

I built my own diy Alephs and they seem to work well on the 4343 mid and highs.

The 4343 is a live hot sounding system and best served with smooth clean power amplifier

[Goldjazz]

Hi Ian thanks, yeah I've read your upgrade threads with interest. Lots of great information there I've learnt quite a bit reading it, and still learning so thanks for that contribution.

As discussed I've been playing around with quad amping (just one speaker) the past couple of days and its quite an interesting exercise as I start to understand the quirks of each driver. As discussed the biggest change was how much clearer the 2420 now sounds, so perhaps that biamp switch is partly to blame as well as you say. I do like the 2420 but it can be a harsh beast, it's just so clear and dominant and needs to be carefully blended in. I think the mosfets of my Perreaux 6000b are a little smoother on it than the harsher (but clearer) Sansui au10000 I also have. I bet a smooth quality class A amp would be the way to go as you say. I at least have a nice, smooth Class A Mark Levinson Ml-1 preamp ontop of everything.

Yes I was in Japan last year and visited many amazing Hifi stores all over the country, so witnessed their passion for the 4343 first hand. Didn't manage to see any 4343's in action in the jazz clubs this time, but will be sure to do that next time.

I am aware of the limitations of the behringer xover I'm currently using, I wasn't aware of the pass labs or firstwatt units you refer to so I'll look into those. I'm also quite interested in the Accuphase f-25. Will depend on if I continue down this quad amp approach or not.

Out of interest do you think there's merit in the quad amp approach or not?





If you search for 4343 upgrade I did a lot on crossover upgrades and the pros and cons of bi am ping.

Essentially the network was based on the 2121 , the 2420 old aluminium diaphragm and the 2405.

The drivers are fairly aggressive in that the 2121 has noticeable edge in its break up mode, the 2420 fades above 7000 and the 2405 is bought in hot to recover the detail.

There is some benefit in using more contemporary crossover capacitors however the best favour you can do is bypass the biamp switches this places contact resistance and prevailing insertion losses in the signal oath. There are post on what to do if you care to look around.

Beyond that the 2421 with the alumina diamond diaphragm is better.

The 4344 was the work of Greg Timbers and was a refinement in drivers and the network over the 4340 and 4343/b

As the active crossovers we found the Passlabs xvr1 was an audible improvement over the JBL and other pro units.

JBL did a great unit for the XP series but is NLA.

I understand Greg had used them and the Pass labs.

Pass now had have a great Firstwatt model B4 that is stunningly good, alternatively look for the Bryston unit.

The distinction is these are both discrete and operate in class A, this transforms the HiFi element into what the Japanese regard as a one of the best loudspeakers of all time.

In the Jazz bars in Tokyo the 4343 has a Cult status. I have seen Passlabs Aleph 2 pure class A power amps driving the 4343s in a bar there and the sound was really impressive.

I built my own diy Alephs and they seem to work well on the 4343 mid and highs.

The 4343 is a live hot sounding system and best served with smooth clean power amplifier

[Goldjazz]

Well, I've had a go a this and I'm pretty pleased with the result so far in terms of how it sounds, but lots more tweaking to do.

So I've got two Behringer CX3400 4-way crossovers, a Perreaux 6000b, a Perreaux 6000c, a BGW 750C, and A crown CE2000. The Crown is on the LF. Crossover at 300Hz to the BGW which takes the Midbass, then Crossover at 1250 to the 6000b, and then at 9KHz to the 6000C. Using a Musical fidelity M1 Dac, and Mark levinson ML-1 pre.

I also have a Rode NT-Usb condensor mic, and a the Room EQ QWizard software. I don't yet have a means of eq, but I'm aiming to get an anologue EQ such as a Klark Teknik DN360. All this gear is being run in a small room at the moment prob 15 feet x 15 feet . The room is partially open plan into a bigger space with effectively part of the wall behind the listener and ton the right side missing. Also One side "wall" is effectively a floor to ceiling glass sliding door, so not an ideal space.

Yeah so I assume the plots below are indicating a lot of peaks and troughs from reflections etc from the room. I've done as much with adjusting gain on the separate amps to get it as flat as possible. As I said no, eq applied yet nor any room treatments yet. Also all the amps are pretty rough, ex hire gear so I'll be going through each amp one by one recapping etc, starting with the second BGW I have. 652176521865219