Orphean Crossover

Hi again, and forgive me asking more questions as I try to fill in some gaps in my understanding.

I have decided to tackle a DIY Orphean build. Initially, at least, I will build a pair of Compact Reference bass units to be equipped with BD15 drive units. I have a good sounding gainclone amplifier available and will utilise that to power the bass units. Obviously the mid/top will be the BMS 4592 drive units, coupled to horns and powered by my Transcendent SE-OTL amplifier (around 1.5W into 8ohms but amazing sound and very quiet so great with high efficiency speakers).

I'm confident on the preceding elements but am unsure how the crossover should be configured and further confused by the info on the BD website, which lists a crossover in relation to the BD15 units but also a filter in relation to the Orphean (which shows a box with, apparently one pair of speaker terminal inputs and two pairs of outputs, seeming to imply a single amplifier for both bass and mid/treble)? Also, how will the mismatch in power/gain of the gainclone and Transcendent amps be accomodated? I would be very grateful for an explanation of the configuration of the Orphean + Compact Ref crossover/filter. Thanks.

Ray

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Hello Ray,

Hi again, and forgive me asking more questions as I try to fill in some gaps in my understanding.

No worries about asking... :good:

I'm confident on the preceding elements but am unsure how the crossover should be configured and further confused by the info on the BD website, which lists a crossover in relation to the BD15 units but also a filter in relation to the Orphean (which shows a box with, apparently one pair of speaker terminal inputs and two pairs of outputs, seeming to imply a single amplifier for both bass and mid/treble)?

I am confident too. The listed crossover for the Compact and Ultra enclosures is a passive crossover connencted in between the bass amplifier and the BD15 bass driver. Additionally there is another crossover (passive line level) where the signal of your main amplifier is used which is passing through this passive line level crossover where the first stage of the crossover is et and where also the gain is adjusted to adjust the differences in sensitivity.

Also, how will the mismatch in power/gain of the gainclone and Transcendent amps be accomodated?

This was done with the passive line level crossover as described above. See also the schematic as example (the passive crossover parts in front of the BD15's are not shown here...) to make things hopefully more clear.

This was the previous situation which is completely different with the REF2010 where this all is done actively but which could be used for your initial system too I guess... :cool:

[image]

Bert

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BD-Design - Only the Best!

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Thanks for the comprehensive response Bert, much appreciated. Currently I feed my Transcendent Amp via a passive switched attenuator (10K, shunt type)- is that going to work OK with the line level part of the Orphean crossover that you have shown?

BTW, I may have created some confusion with my use of the word 'confident'? I am confident that the Orphean with Compact bass unit will be excellent but in the context I used I meant that I am confident that I understand what I'm doing and can build it.

Thanks again.

Ray

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Thanks for the comprehensive response Bert, much appreciated. Currently I feed my Transcendent Amp via a passive switched attenuator (10K, shunt type)- is that going to work OK with the line level part of the Orphean crossover that you have shown?

As long as you use the loudspeaker output connectors of the Transcendent amplifier to feed that crossover then yes..

BTW, I may have created some confusion with my use of the word 'confident'? I am confident that the Orphean with Compact bass unit will be excellent but in the context I used I meant that I am confident that I understand what I'm doing and can build it.

Even better... :grin:

Bert

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BD-Design - Only the Best!

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Hi Bert,

So, what does the filter that is placed after the bass amp/before BD15 do for the sound? Wouldn't it be more ideal to do all of the sound "shaping" before the amp, so that the amp had only the BD15 driver to deal with? :blush:

Steve

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Hi Steve,

So, what does the filter that is placed after the bass amp/before BD15 do for the sound? Wouldn't it be more ideal to do all of the sound "shaping" before the amp, so that the amp had only the BD15 driver to deal with?

The extra crossover is more effective giving a steeper roll-off which is good to have less overlap and also giving less noise (some amps do ssssssss or give other audible high frequency noise).

The passive line level crossover stages influence eachother too much making the theoretical slope less strong.

Bert

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BD-Design - Only the Best!

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Thinking out loud again Bert, your previous answer implies that there is no filtering of the mid/treble BMS compression driver?

Ray

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Hi Ray,

Thinking out loud again Bert, your previous answer implies that there is no filtering of the mid/treble BMS compression driver?

Forgot to answer that one... :blush:

There is a crossover needed. The black box is the part crossing not only the mid-high frequencies but also dictates the lowest frequencies of the horn/driver combination.

The crossover frequencies for the Orphean MkII are set to 270Hz and 7kHz

Bert

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BD-Design - Only the Best!

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Cheers Bert, now I understand.

Ray

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Orphean Crossover (BD-Design)