Open baffle test
My interest in trying an open baffle woofer to blend with the ribbon was piqued by the earlier posts, so I put together a pair of mini-Orions, since I already had the 8" required Vifa woofers used in the Centaurs. I paired them with a Fountek fr58ex that I have used previously. The idea is to evaluate the 8" woofer as a candidate for duty with the 26" ribbon in a revised open baffle. I had enough cherry boards laying around to knock together the cabinets(?) and didn't want to embark on a major baffle project for the ribbons until I had a certain degree of confidence that the woofers would be satisfactory for the eventual application.
Well, this little combo is quite stunning, crossed at 2k with LR4 slopes and equalized with my minidsp. Excellent extension down to 80Hz. The separate sealed sub takes over from there.
The next step will be to get some mdf and try a 15" wide baffle arrangement per the original Centaur and somehow incorporate a subwoofer without making the whole assembly too large.
My interest in trying an open baffle woofer to blend with the ribbon was piqued by the earlier posts, so I put together a pair of mini-Orions, since I already had the 8" required Vifa woofers used in the Centaurs. I paired them with a Fountek fr58ex that I have used previously. The idea is to evaluate the 8" woofer as a candidate for duty with the 26" ribbon in a revised open baffle. I had enough cherry boards laying around to knock together the cabinets(?) and didn't want to embark on a major baffle project for the ribbons until I had a certain degree of confidence that the woofers would be satisfactory for the eventual application.
Well, this little combo is quite stunning, crossed at 2k with LR4 slopes and equalized with my minidsp. Excellent extension down to 80Hz. The separate sealed sub takes over from there.
The next step will be to get some mdf and try a 15" wide baffle arrangement per the original Centaur and somehow incorporate a subwoofer without making the whole assembly too large.
Attachments
Next step OB
I replaced the Fountek tweeter with the truncated Apogee ribbon baffle and stood the ribbon , 8" woofer baffle and 10" sub in a compact heap. This ribbon beats all I have tried. Crossed the ribbon/woofer at 700Hz. Sub cuts in at about 63Hz.
With a little creativity I could build a Minigrand type assembly, but with the 8" woofer replacing the Stage woofer panel.
Bill...if you have the workshop facilities to make an open baffle arrangement with your ribbon, it would be well worth salvaging.
This performs well in excess of my Fountek tweeter build. The ribbon needs to be elevated though(sit on top of the sub) to maximize the soundstage.
Peter
I replaced the Fountek tweeter with the truncated Apogee ribbon baffle and stood the ribbon , 8" woofer baffle and 10" sub in a compact heap. This ribbon beats all I have tried. Crossed the ribbon/woofer at 700Hz. Sub cuts in at about 63Hz.
With a little creativity I could build a Minigrand type assembly, but with the 8" woofer replacing the Stage woofer panel.
Bill...if you have the workshop facilities to make an open baffle arrangement with your ribbon, it would be well worth salvaging.
This performs well in excess of my Fountek tweeter build. The ribbon needs to be elevated though(sit on top of the sub) to maximize the soundstage.
Peter
Attachments
I can blag the machining (was thinking of going Corian), or just cut the cabinet off the minors. Problem for me is space behind the speaker. I have 1.5m at best due to tiny room.
Corian worktop is around 24" wide when upturned...
I will measure some things up tonight.
Corian worktop is around 24" wide when upturned...
I will measure some things up tonight.
My speakers are <1.0m from the wall behind. I too, have a fairly small room, roughly 4.5m x 5m, but with ceiling sloping from 2.6m to 4.2m high.
For a small room, I'd suggest looking at an 8" driver on a 12" or 15" wide baffle. Check out the Nao Note ll speaker for ideas.
Corian sounds like a great idea for the baffle. I've never used - is it easily machined with woodworking tools?
Peter
For a small room, I'd suggest looking at an 8" driver on a 12" or 15" wide baffle. Check out the Nao Note ll speaker for ideas.
Corian sounds like a great idea for the baffle. I've never used - is it easily machined with woodworking tools?
Peter
11ft by 12ft here, but with 2 sofas, piano, tv, records, bookcases, cds and a fireplace fighting for space. and the bookcase extension limits me on one side. But staying within the minors 14" width I can just squeeze it in.
I don't know about machining corian, but know people who do who owe me favours.
I don't know about machining corian, but know people who do who owe me favours.
well having done some measurements I cannot fit anything wider in the room at the moment, so for now will have to stay with the existing baffles, which limits me to 6.5" drivers. As I have a sub I can cut in at 120Hz this is not so bad, but will need more than one driver. The existing cutout is bang in the middle of the ribbon, so the temptation is to have 3 in a line, but that could get very expensive very quickly.
If I leave the outer sides on the current cabinet then I get a useful extension on the baffle (and something to support the speakers). So pending locating a good driver that isn't £80 a pop I might be in .
currently looking at the scanspeak 15W 8434 and SEAS CA18RNX as a possible. A variant of the SS is used in some of the NaO open baffles so has pedigree. The 18sound 6ND430-16 is tempting, but too expensive as is the Tang Band W6-1721 unless I run with 1 and keep spls down. I doubt this approach would lead to joy. The original Vifa is back in production, which would save money, but no publised xmax 🙁
So far just finding out what I don't know still!
If I leave the outer sides on the current cabinet then I get a useful extension on the baffle (and something to support the speakers). So pending locating a good driver that isn't £80 a pop I might be in .
currently looking at the scanspeak 15W 8434 and SEAS CA18RNX as a possible. A variant of the SS is used in some of the NaO open baffles so has pedigree. The 18sound 6ND430-16 is tempting, but too expensive as is the Tang Band W6-1721 unless I run with 1 and keep spls down. I doubt this approach would lead to joy. The original Vifa is back in production, which would save money, but no publised xmax 🙁
So far just finding out what I don't know still!
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I really like the Peerless Nomex. It is used in the Elsinore and a couple of Troels Gravesen speakers. Available in the US for about $60.00. I used four in my Centaur mods at one time while I repaired the 8" Vifas. Then used them in other builds.
Peter
Peter
They look nice, but xmax is low compared to the others I am looking at (at least if the published specs are right). But the price is good. The SEAS is currently looking the most interesting for xmax/$. I just have to work out the critical parameters.
Just realised I might be able to do something clever to get 2 drivers next to each other. Need to sketch something.
You may have this info....but others may get some thing out of more info
These Spec are for the (Centaur) only.... NOT the Centar Minor that have the same 26" MT ..........Keep up the Good work.... All the Apogees that are Not Bussing ....Hehe
Still to day sand up with Some of the Best Speaker ever made.....well to me any way...I have The Stages an Minors.....
An Mr J Bloom felt that his passive Apogee crossover sounded better than the DAX
Specifications
Height
117cm
Width
38cm
Depth
28cm
Bass driver
8" Dynamic cone
Midrange/Tweeter
26" Aluminium/Kapton ribbon (etched 6 segment)
Max Sound Level
107 dB @ 4 meters with a 50 W amplifier
Sensitivity @ 3m
84dB
Frequency response
38Hz (-3dB @ 45Hz) to 20Hz
Crossover frequency (electronic)
500Hz
Suggested amp power
100W (into 8 ohms) 200W (into 4 ohms)
Impedance nominal/minimum
5ohms / 3ohms
Weight
65lbs each
Finishes available
Silver grey, rosewood, walnut, blonde oak and mahogany
Price at time of first sale
�1,845 (UK July 1991)
Description of the North Creek Crossover
The North Creek tweeter high-pass network topology and component values largely unchanged. I tried a few other topologies and varied the high pass Q, but in the end I kept returning to a Cascade Bypassed 67.1uF/1.5mH second order high pass. There are two reasons for this: 1) it is my feeling the current network pushes the tweeter ribbon as low as it will go while still remaining an effective transducer; 2) the failure level is so low that it may be the most dependable driver in history. The Cascade Bypass is accomplished with a group of Zen and Crescendo polypropylene capacitors. The 1.5mH inductor is 12 AWG.
I changed the trap quite a bit, as I felt it was still a bit too bright and also too narrow. This may have to do with the age of the Kapton tweeter ribbon, which is now extremely well broken in.
These Spec are for the (Centaur) only.... NOT the Centar Minor that have the same 26" MT ..........Keep up the Good work.... All the Apogees that are Not Bussing ....Hehe
Still to day sand up with Some of the Best Speaker ever made.....well to me any way...I have The Stages an Minors.....
An Mr J Bloom felt that his passive Apogee crossover sounded better than the DAX
Specifications
Height
117cm
Width
38cm
Depth
28cm
Bass driver
8" Dynamic cone
Midrange/Tweeter
26" Aluminium/Kapton ribbon (etched 6 segment)
Max Sound Level
107 dB @ 4 meters with a 50 W amplifier
Sensitivity @ 3m
84dB
Frequency response
38Hz (-3dB @ 45Hz) to 20Hz
Crossover frequency (electronic)
500Hz
Suggested amp power
100W (into 8 ohms) 200W (into 4 ohms)
Impedance nominal/minimum
5ohms / 3ohms
Weight
65lbs each
Finishes available
Silver grey, rosewood, walnut, blonde oak and mahogany
Price at time of first sale
�1,845 (UK July 1991)
Description of the North Creek Crossover
The North Creek tweeter high-pass network topology and component values largely unchanged. I tried a few other topologies and varied the high pass Q, but in the end I kept returning to a Cascade Bypassed 67.1uF/1.5mH second order high pass. There are two reasons for this: 1) it is my feeling the current network pushes the tweeter ribbon as low as it will go while still remaining an effective transducer; 2) the failure level is so low that it may be the most dependable driver in history. The Cascade Bypass is accomplished with a group of Zen and Crescendo polypropylene capacitors. The 1.5mH inductor is 12 AWG.
I changed the trap quite a bit, as I felt it was still a bit too bright and also too narrow. This may have to do with the age of the Kapton tweeter ribbon, which is now extremely well broken in.
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Failure level low? I've had to repair all 4 drivers in my minors, but they are 22 years old now. Still have a magic tho.
So you stuck with 750Hz or 500Hz for X-over?
So you stuck with 750Hz or 500Hz for X-over?
Are you saying you had to repir the MT also?
or you have 2 pr of mioners
My stages have the basic crossover as the Centaur..........with the 67-70mf an the trap...........the minors only have a 30mf an a trap...if I were going to make changes to the MT...........it would be like the slant 6....I got to hear theses...lot more output out of the MT with it being open.............
or you have 2 pr of mioners
My stages have the basic crossover as the Centaur..........with the 67-70mf an the trap...........the minors only have a 30mf an a trap...if I were going to make changes to the MT...........it would be like the slant 6....I got to hear theses...lot more output out of the MT with it being open.............
Attachments
![images[1].jpg](/community/data/attachments/415/415667-ef081c424ba601040ac9a30f801001c1.jpg?hash=7wgcQkumAQ)
Having a little trouble interpreting you I am afraid. what is 'MT' in this context.
I have had to fix both ribbons and both cones on my speakers over the time I have had them. Oh and one of the cabinets 'fell off' at one point. Sensible people would walk away at this point, but I have a soft spot for them!
I have had to fix both ribbons and both cones on my speakers over the time I have had them. Oh and one of the cabinets 'fell off' at one point. Sensible people would walk away at this point, but I have a soft spot for them!
Ah, never seen them called that as there is no other tweeter. Ribbon or Ribbon tweeter seems normal convention. Maybe mine have had a hard life, but the ribbons are borked now and need replacing. I nursed them for 10 years!
Most tweeter don't go down to the mid 750-1000hz...not most that I know of....but it all good .....
Look your working with them...to make them better in your case....keep giving us your input on what you find ...thanks
Look your working with them...to make them better in your case....keep giving us your input on what you find ...thanks
Well all mods make things better,<dredd> its the law </dredd>
My view is that the ribbon on the minors is arguably the best Apogee made, but the rest of the speaker had to be built down to a price because of that. If I take care I should be able to end up with something pretty good. But note I am not claiming I am cleverer that Mr. Bloom, just I have a bigger per unit budget 🙂
My view is that the ribbon on the minors is arguably the best Apogee made, but the rest of the speaker had to be built down to a price because of that. If I take care I should be able to end up with something pretty good. But note I am not claiming I am cleverer that Mr. Bloom, just I have a bigger per unit budget 🙂
Bill...
Over the next few days I plan to experiment(by ear and an spl meter) with the peerless nomex pair in mtm format open baffle. I would like to compare them to the 8" vifa, which I already know is very satisfactory in OB. The baffles are already glued up and will use a vifa xt25 or the little 2" fountek for tweeter.
The sum of the Sd for the 2 Peerless is greater than the Vifa and the x-max is comparable, maybe even greater.
Not sure how significant x-max is anyway, since I will be crossing to a sub.
Peter
Over the next few days I plan to experiment(by ear and an spl meter) with the peerless nomex pair in mtm format open baffle. I would like to compare them to the 8" vifa, which I already know is very satisfactory in OB. The baffles are already glued up and will use a vifa xt25 or the little 2" fountek for tweeter.
The sum of the Sd for the 2 Peerless is greater than the Vifa and the x-max is comparable, maybe even greater.
Not sure how significant x-max is anyway, since I will be crossing to a sub.
Peter
I am not sure either, but given the narrow baffle I am constrained by I will need considerable gain 100-300Hz, with maybe 12dB extra at the sub x-over point. In that scenario xmax does become a consideration. But I need to do the sums. Luckily I have a number of options with +/-6mm xmax.
Been plugging some numbers into Tolvan Data to get some first order approximations. Turns out its better than I had thought and I only need 6dB of boost for the low frequencies. Also interesting is that you get a flatter response 300Hz up if one driver is in the centre vertically (i.e. where the current hole is without the stands). Best response for this simulation (baffle effects) is with the second driver spaced 30cm away, but that doesn't tell me much about how that will change the polar plot.
This is looking very doable, which can only mean that I have not taken something important into account!
This is looking very doable, which can only mean that I have not taken something important into account!
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