I like the Minor higher crossver point.....but i have the stages allso...so i gess i like the diff .....i run my stages with only the 70mf as the crossover....here the crossovers................thay all sound killer to me....
..http://www.apogeespeakers.com/projectstech/centaur_minor_crossover.pdf
..http://www.apogeespeakers.com/projectstech/centaur_minor_crossover.pdf
Attachments
![stage_crossover[1].jpg](/community/data/attachments/402/402417-a0d727374c499bb17e41d0daa532bded.jpg)
![centaur_crossover[1].jpg](/community/data/attachments/402/402425-5abf327eec63db0ae40476b3c7624fe5.jpg)
http://www.apogeespeakers.com/projectstech/centaur_minor_crossover.pdf is the minor crossover and matches what I have seen when the cabinet fell off mine.
Some things about the schematic don't make sense. Not least that its second order but ribbon and woofer are in phase. I need to start another thread on understanding the design decisions on the hybrids, unless the OP doesn't mind us doing it here.
Some things about the schematic don't make sense. Not least that its second order but ribbon and woofer are in phase. I need to start another thread on understanding the design decisions on the hybrids, unless the OP doesn't mind us doing it here.
Thanks Bill, the phase orientation doesn't surprise me. Phase coherency was a hot topic when the Minor was designed. The hole in response across the x-over range also shows up in Stereophile's measurements. Apogee recommended listening off the inside axis, I suspect leveraging lobing to fill it in. The hop from second to first order is a head scratcher and negatively audible to me.
After twenty years with the Minor, like you the performance of that ribbon continues to impress.
Yeah, that particular crossover diagram is incorrect. (I noticed that many years ago on the old Apogee forum.)
Unfortunately, the Apogee crossover diagrams are user supplied in most cases and mistakes were sometimes made in analyzing the wiring configurations and translating them into conventional format schematics.
Cheers,
Dave.
well starting at the top, the crossover I linked, which is close to the Mk1 eyeball of a real minor crossover seems to have a presence dip around 3KHz based a quick back of envelope calculation. Any one have any ideas on this?
Once that cleared then its the question of how low you can run the 26" ribbon. 750Hz isn't a bad point as you are pretty much splitting the power 50/50 between the drivers, but is there an advantage in going a bit lower with LR4 electrical?
Once that cleared then its the question of how low you can run the 26" ribbon. 750Hz isn't a bad point as you are pretty much splitting the power 50/50 between the drivers, but is there an advantage in going a bit lower with LR4 electrical?
Bill,
If you believe the component values on that notch filter in the high-pass section, then the dip frequency is approximately 9.2khz. (10uF/30uH) I'm not sure how you're computing 3khz. However, 3khz seems like a more realistic frequency considering that driver. It's like I said, you can hardly believe anything you see regarding Apogee schematics.
I think it's probably preferable to run the ribbons as low as they can go.....considering the electrical roll-off of the filter you use. If you start seeing them move around quite a bit, it's time to raise the xover frequency or steepen the slope or both.
Cheers,
Dave.
It was a 'quick' calculation some time ago so I can believe that as I didn't check it, but made a note to come back and work out why it was there. In what was a cheap speaker for Apogee they would have had a reason for putting it in. Looking at the impedance plots from the stereophile measurements there is is a wrinkle in the impedance plot around the 9KHz point so that makes sense. Looking at the frequency plots again there is a hump off axis vertically so I would need some correction for that.
Hmm off to muse choices from 500Hz down. If I didn't have such a small room I would be tempted to go Open baffle.
Hmm off to muse choices from 500Hz down. If I didn't have such a small room I would be tempted to go Open baffle.
Judging from Stereophile's measurements:
http://www.apogeespeakers.com/reviews/Centaur_Minor_Stereophile.pdf
the electrical crossover is around 550 Hz and the response hole is centered around 1 kHz. The inside edge lobing acting as fill is also clearly illustrated. It has me thinking an open baffle vertical quad of high quality drivers on either side of the ribbon, crossed to a sub, might be a worthwhile approach.
http://www.apogeespeakers.com/reviews/Centaur_Minor_Stereophile.pdf
the electrical crossover is around 550 Hz and the response hole is centered around 1 kHz. The inside edge lobing acting as fill is also clearly illustrated. It has me thinking an open baffle vertical quad of high quality drivers on either side of the ribbon, crossed to a sub, might be a worthwhile approach.
There are certainly better ways to do it than apogee did. If the damned things weren't so good at some things i would abandon them for something with different compromises. The transition from line to point source is one thing that I haven't got a full handle on from a spacial perspective. What drive units would you consider for an array?
The other thing I wonder if is the ribbon would benefit from different loading with some sort of waveguide.
The other thing I wonder if is the ribbon would benefit from different loading with some sort of waveguide.
Got say,I got this pr of Minors for $200-250..with stands....look like new..picket them up for the MT ribbons...incase I lost one of my stages ..but I like the topend better than my stages....but ezey to see why....the minor ribbon is open in the back an the base box......... works like a horn .....I get more hight in the image, than the stages an for the money there a lot too for give....crossover are made with better parts than some B&W 801-803s I have paid big money for...back in the 90s...........
Haven't given it significant thought. Zaph's driver looked interesting for a single row of four, the Dayton RS100-4 for double. This is from a passive x-over perspective. If I were to do this the goal would be covering the lower range of male voice with a single driver, which means at least down to 100 Hz.
Re: the transition, I still hear its presence. On axis the flat first arrival does wonders to minimize the impact but to my ear it's central to the Minor's overall character.
I haven't either, mainly because I know that it is very easy to make things worse and I am am relearning some stuff I haven't used since the 80s ( 3 kids use up a lot of your free time for 20 years).
I got as far as looking at some OB calcs but realised I just don't have a big enough room for that, so need to stick with a box for low frequencies. The cabinet on the minors is at best adequate so happy to hack that off and build a new one. I have some dibs on enough Corian to build new baffles so can start from scratch.
Over the last week I have been wondering about a midrange ribbon to get down lower, but that is just thoughts rather than any calculations yet.
I got as far as looking at some OB calcs but realised I just don't have a big enough room for that, so need to stick with a box for low frequencies. The cabinet on the minors is at best adequate so happy to hack that off and build a new one. I have some dibs on enough Corian to build new baffles so can start from scratch.
Over the last week I have been wondering about a midrange ribbon to get down lower, but that is just thoughts rather than any calculations yet.
Thanks for the stimulus, you guys!
Open baffle lower mid/woofer seems like it may be worth experimenting with.
The original Vifa 8" is a candidate, also I have four peerless 6.5" nomex that are doing other duty right now. How about a pair of Hivi B4 on each side?
I haven't played with open baffle since the 1960s - sounds like fun.
Open baffle lower mid/woofer seems like it may be worth experimenting with.
The original Vifa 8" is a candidate, also I have four peerless 6.5" nomex that are doing other duty right now. How about a pair of Hivi B4 on each side?
I haven't played with open baffle since the 1960s - sounds like fun.
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