Biamping with 2 x identical amps, breakthrough

[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]

[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 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.

Have fun with your active 4 way system.

[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]