Bill,
I would also try modeling an asymmetric baffle for your woofer add-ons. That will spread the cancellation distance and probably yield an easier equalization scheme.
That may or may not have an aesthetic appeal for you also.
Dave.
I would also try modeling an asymmetric baffle for your woofer add-ons. That will spread the cancellation distance and probably yield an easier equalization scheme.
That may or may not have an aesthetic appeal for you also.
Dave.
first off, happy new year from this side of the pond.
If by asymmetric you mean a non-regular polygon, I have considered it and parked it for this round of mods, for 2 reasons
1. It is non-reversable so I really need to do this when I start building new baffles.
2. Still trying to understand what I don't know yet, so would be randomly iterating on the sim. If I get a clue on how it all works, then I will know what do
3. I can't be wider or taller.
If by asymmetric you mean a non-regular polygon, I have considered it and parked it for this round of mods, for 2 reasons
1. It is non-reversable so I really need to do this when I start building new baffles.
2. Still trying to understand what I don't know yet, so would be randomly iterating on the sim. If I get a clue on how it all works, then I will know what do
3. I can't be wider or taller.
OB mock-up
Just assembled the OB pair using the Peeress6.5" Nomex woofer.
Baffle is 14" wide and 36" high, with tapered wings. 12" space under the baffle for the Ripole sub, plate amp and D class amp boards when I get them. Presently running stereo Symasym per side.
Playing with the minidsp and currently crossing at 500Hz, LR4/LR2 equalizing to reduce room modes.
I had to taper the highs with a -5db shelf starting at about 1500Hz. The 26" ribbon has always boosted the top end somewhat but this arrangement seemed to accentuate that.
Vertical dispertion extremely poor as per Apogee, but the horizontal dispertion seems much improved and doesn't suffer the limited sweet spot. I can sit anywhere on the couch and get a really good stereo image.
So far, very pleased.
Peter
Just assembled the OB pair using the Peeress6.5" Nomex woofer.
Baffle is 14" wide and 36" high, with tapered wings. 12" space under the baffle for the Ripole sub, plate amp and D class amp boards when I get them. Presently running stereo Symasym per side.
Playing with the minidsp and currently crossing at 500Hz, LR4/LR2 equalizing to reduce room modes.
I had to taper the highs with a -5db shelf starting at about 1500Hz. The 26" ribbon has always boosted the top end somewhat but this arrangement seemed to accentuate that.
Vertical dispertion extremely poor as per Apogee, but the horizontal dispertion seems much improved and doesn't suffer the limited sweet spot. I can sit anywhere on the couch and get a really good stereo image.
So far, very pleased.
Peter
Attachments
The dipole baffle generally widens the response (relative to the original box) until you get all the way to the cancellation nulls. In your case, there's also wall reflections from the higher frequencies of the 6.5" driver range now contributing to the off-axis response. It should be easy to hear the relative difference just by walking around the speaker as you're listening.
I like the idea of ultimately using multiple drivers.....maybe four total....on your baffle. Those Peerless Nomex drivers are terrific and an excellent choice for this project.
Nice setup.
Dave.
I like the idea of ultimately using multiple drivers.....maybe four total....on your baffle. Those Peerless Nomex drivers are terrific and an excellent choice for this project.
Nice setup.
Dave.
Looking good. I am still waiting for the first parts to arrive. Have worked out how to build the amps into the stands (although looking at your ripoles that is a very tempting option too. Will have to research those.
You might get better response moving the driver up a bit. but depends if you want to correct a peak at 300Hz or a dip at 1kHz.
How are the drivers handling the workload? That was my biggest worry over chopping the cabinet off.
And when I showed the pic to SWMBO and she said she was ok with the look 🙂
You might get better response moving the driver up a bit. but depends if you want to correct a peak at 300Hz or a dip at 1kHz.
How are the drivers handling the workload? That was my biggest worry over chopping the cabinet off.
And when I showed the pic to SWMBO and she said she was ok with the look 🙂
note: ebay is dangerous! still pondering upgrades to the woofer, and nearly got caught in a bidding war for some metal cone SEAS W17, but seriously mulling a pair of scanspeak 18W8545 that should be really cheap as need a refoam.
Won the 18W8545. Not the kapton wound version, but still seems to be a good upgrade on the peerless that came as stock and under $100 including the refoam kit (needed on one unit). Need to enlarge the cutout by a few mm, which could be fun, unless anyone has some good tips?
BTW have posted a question about open baffle response over in the multiway forum to try and get more eyes. In theory it would seem that, without stands the position of the woofer is about optimal, but I worry I have missed something.
BTW have posted a question about open baffle response over in the multiway forum to try and get more eyes. In theory it would seem that, without stands the position of the woofer is about optimal, but I worry I have missed something.
Well done, Bill.
Did you win a pair of woofers?
As far as opening up the cutout on the baffle, what I have done in the past requires just a router with a circle cutting jig.(I made mine from a piece of plywood).
Cut a circle from any flat, approx 3/4" stock that is a push fit in the existing cutout.(needs to be almost a press fit to stop it from spinning when you make the new cutouts - I have wrapped electrical tape around the circle to ensure a tight fit.) Using the centre hole in the new circle as the pivot, rout out the required new driver recess then the new cut out. Have fun.
Peter
Did you win a pair of woofers?
As far as opening up the cutout on the baffle, what I have done in the past requires just a router with a circle cutting jig.(I made mine from a piece of plywood).
Cut a circle from any flat, approx 3/4" stock that is a push fit in the existing cutout.(needs to be almost a press fit to stop it from spinning when you make the new cutouts - I have wrapped electrical tape around the circle to ensure a tight fit.) Using the centre hole in the new circle as the pivot, rout out the required new driver recess then the new cut out. Have fun.
Peter
I did. Just need to order the new surround for the damaged one.
I will try your method, although with the new hole only being 6mm increase in diameter could be challenging.
I will try your method, although with the new hole only being 6mm increase in diameter could be challenging.
Then you might want to glue the circle piece into the cut out.
I did some test frequency measuring today of the raw drivers, separately without any crossover or EQ.
L and R channels measured within 1db of each other.
Woofers were +-2db from 312hz to 3.12khz with the lowest point being at 1.25khz, a wide very shallow dip. Woofer output rose 5/6db at 5khz and fell sharply after 6.3khz. Woofer output fell 6db/octave below 312hz.
Ribbon output was + - 2db from 400hz to 2.5 kHz and then climbed 6db/octave to 8khz. Then fell off(my old ears reach their limit at 10khz anyway).
The tweeter exhibited a wide shallow dip centered at 900hz. Tweeter output was down 3db at 250hz.
I have since adjusted the minidsp to cross at 700hz LR4/LR2 and with very gentle EQ.
I'm still working on the low end where room modes affect each channel differently. But very pleased with the results so far.
I did some test frequency measuring today of the raw drivers, separately without any crossover or EQ.
L and R channels measured within 1db of each other.
Woofers were +-2db from 312hz to 3.12khz with the lowest point being at 1.25khz, a wide very shallow dip. Woofer output rose 5/6db at 5khz and fell sharply after 6.3khz. Woofer output fell 6db/octave below 312hz.
Ribbon output was + - 2db from 400hz to 2.5 kHz and then climbed 6db/octave to 8khz. Then fell off(my old ears reach their limit at 10khz anyway).
The tweeter exhibited a wide shallow dip centered at 900hz. Tweeter output was down 3db at 250hz.
I have since adjusted the minidsp to cross at 700hz LR4/LR2 and with very gentle EQ.
I'm still working on the low end where room modes affect each channel differently. But very pleased with the results so far.
Those measurements are certainly of the frequencies and directions that I would have expected, so gives me hope that I am in the ballpark.
Interesting to note the 900Hz dip on the ribbon. Does explain the big suckout on the minors. Correcting that on its own will bring big dividends I suspect.
Interesting to note the 900Hz dip on the ribbon. Does explain the big suckout on the minors. Correcting that on its own will bring big dividends I suspect.
Looking at the pictures of the Centauer with the line array mid/tweeter and a single 6.5" woofer, made me think of an old Dali implementation much the same, but where they had placed the woofer behind a second diaphragm made of thin plastic (like the diaphragm of an ELS) soposedly making the radiation fit the mid/tweet section better i.e. making it more line array like ...... not sure it worked, but just putting the idea in 😉
... bit difficult to explain but hope you get the idea .... was a smaller brother to the Skyline models as I recall ... see if I can find a picture 😉
/Baldin
... bit difficult to explain but hope you get the idea .... was a smaller brother to the Skyline models as I recall ... see if I can find a picture 😉
/Baldin
Dali DaCapo
... and sorry the woofer was 8 inch .... 😉
FS: Relist and Price Drop: [Syd] Rare Vintage Dali DaCapo Ribbon Speakers - Classifieds Archive - StereoNET
rare-vintage-dali-dacapo-ribbon-speakers/
... and sorry the woofer was 8 inch .... 😉
FS: Relist and Price Drop: [Syd] Rare Vintage Dali DaCapo Ribbon Speakers - Classifieds Archive - StereoNET
rare-vintage-dali-dacapo-ribbon-speakers/
Attachments
Think of it as a two chamber enclosure. You have the woofer looking into a closed box on both sides, and in on chamber is a passive radiator.
The pressure made by the active woofer will drive the passive radiaor, which in this case is a thin plastic foil. This way you'll transfer the pressure made by the smaller woofer to a larger passive radiatorgoing from top to buttom of the enclosure, same as the mid/tweeter section.
This will only work in the lowest frequencies. Further up the thin foil will be almost transperent to the sound waves.
If it really works ..... not sure how efficient it is 😉
/Baldin
I have belt Speakers with passive radiators.....Back in the 70s...Thay were great..
If I were to rework my Apogee Minors...I would just Add a passive radiator to the stock box...
I like the Sound better than a port....port cost little...so there used.
I sold a lot of Klipsch...when I was in the Audio bizz....big passive radiator bilder...
Dali...Has made a lot of ribbon type speakers...some sale here in the US ...Some don't.....vary diff sound...well, the ones I have heard.....
If I were to rework my Apogee Minors...I would just Add a passive radiator to the stock box...
I like the Sound better than a port....port cost little...so there used.
I sold a lot of Klipsch...when I was in the Audio bizz....big passive radiator bilder...
Dali...Has made a lot of ribbon type speakers...some sale here in the US ...Some don't.....vary diff sound...well, the ones I have heard.....
In the DaCapo, the extra diaphragm does not have the same intended function as a "normal" passive radiator, where it would work as a port, extending the lower end.
Here the intentionwas to alter the radiation pattern.
But I actually rather doudt it is effitient at that .... but would be fun to try out .... quite easily done I would think 🙂
Here the intentionwas to alter the radiation pattern.
But I actually rather doudt it is effitient at that .... but would be fun to try out .... quite easily done I would think 🙂
Well just a 6"-7" passive radiator well cut the stock drivers THD in the minor in 1/2...almost.....an give better bass I think?....
It like going ative...yes it can sound better an you well get less movement in the drivers... an you can play one driver louder than the other....an get a diff sound.
Back when I had my Duettas sig...I had a Krell KBX crossover ...an krell amps...but in the end with just one amp sounded almost as good...with out all the extra amps an wires.........just saying...
But like the passive radiator ....well it work ...you wont know if you don't go...
I have read Jason Bloom like the sound of his stock passive crossovers over going ative.............
Look like Dali tried a lot of thing....you got give them that....
It looks like we have lost more info...the apogeespeakers.com.........site is DEAD....
As I have sead befor.....
Thanks for any an all info on these old killer Apogee speakers.....maybe can keep these pages ...........
It like going ative...yes it can sound better an you well get less movement in the drivers... an you can play one driver louder than the other....an get a diff sound.
Back when I had my Duettas sig...I had a Krell KBX crossover ...an krell amps...but in the end with just one amp sounded almost as good...with out all the extra amps an wires.........just saying...
But like the passive radiator ....well it work ...you wont know if you don't go...
I have read Jason Bloom like the sound of his stock passive crossovers over going ative.............
Look like Dali tried a lot of thing....you got give them that....
It looks like we have lost more info...the apogeespeakers.com.........site is DEAD....
As I have sead befor.....
Thanks for any an all info on these old killer Apogee speakers.....maybe can keep these pages ...........
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