@Davey: what ribbon impedance were you using for your response curve in post 126? Had too much xmas cheer so getting a 350Hz x-over point for the cct in post 125.
Bill,
You can ignore the low-end roll-off behavior in that graph because I had the simulation set to sum the drivers with a normal polarity connection. I was only illustrating the notch filter response in that graph.
I believe the frequency of that notch filter is correct.
Stereophile's impedance sweep of the Stage crossover from 1990/1994 shows the impedance rise at approximately 10khz, which corresponds to the simulation.
Apogee Stage & Mini-Grand loudspeakers 1990 Measurements | Stereophile.com
Also, take note of Figure 10 on this page:
Apogee Stage & Mini-Grand loudspeakers 1994 Measurements | Stereophile.com
Dave.
You can ignore the low-end roll-off behavior in that graph because I had the simulation set to sum the drivers with a normal polarity connection. I was only illustrating the notch filter response in that graph.
I believe the frequency of that notch filter is correct.
Stereophile's impedance sweep of the Stage crossover from 1990/1994 shows the impedance rise at approximately 10khz, which corresponds to the simulation.
Apogee Stage & Mini-Grand loudspeakers 1990 Measurements | Stereophile.com
Also, take note of Figure 10 on this page:
Apogee Stage & Mini-Grand loudspeakers 1994 Measurements | Stereophile.com
Dave.
George Short....on the Stage....this is just more info for others...that my not have seen or noitall...an with high excursion an twisting of the MT there has to be heat bildup!
An I well say driving a pr of Stages with a pr of Krell MDA 500 dif amps....can push vary hard..an sound great....
"The original crossover design was a simple Linkwitz-Riley second order with the woofer in reversed phase. This type of network allows for the gentlest blending of the different drivers throughout the crossover region and also required the fewest crossover components. The second order high pass also protected the tweeter ribbon from( overexcursion, and in fact the ribbon will begin to twist at high excursion) long before it goes into a failure mode"
"The Apogee Stage was superbly designed loudspeaker, considered among the best sounding loudspeakers available in its day, and still much better sounding than the vast majority of loudspeakers produced today. What really amazes me is that the loudspeaker was designed almost completely by ear; the time-windowing measurement equipment that is commonplace today had not been developed in 1988, and this loudspeaker is virtually impossible to measure by conventional means."
An I well say driving a pr of Stages with a pr of Krell MDA 500 dif amps....can push vary hard..an sound great....
"The original crossover design was a simple Linkwitz-Riley second order with the woofer in reversed phase. This type of network allows for the gentlest blending of the different drivers throughout the crossover region and also required the fewest crossover components. The second order high pass also protected the tweeter ribbon from( overexcursion, and in fact the ribbon will begin to twist at high excursion) long before it goes into a failure mode"
"The Apogee Stage was superbly designed loudspeaker, considered among the best sounding loudspeakers available in its day, and still much better sounding than the vast majority of loudspeakers produced today. What really amazes me is that the loudspeaker was designed almost completely by ear; the time-windowing measurement equipment that is commonplace today had not been developed in 1988, and this loudspeaker is virtually impossible to measure by conventional means."
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Davey: Ok, well that matches the centaur minor response from the published schematic and the north creek website, so defiantly needed to flatten response. Question is how best to implement at line level to allow for tweaking.
tyu,
George's commentary on the Stage was posted many years ago. Anyone who is even moderately interested in the Stage or has perused the various Apogee forums has read that. Quoting it again here provides no new information.
Likewise, it's a complete waste of bandwidth for you to paste Robert Harley's entire Slant 6 test report into a posting here. Anybody can Google that if they so choose.
If you've got something new to offer and/or can answer some questions regarding your various assertions, please do so. Otherwise I'm not sure what your interest is in posting other than just juvenile commentary.
My goodness.
Dave.
George's commentary on the Stage was posted many years ago. Anyone who is even moderately interested in the Stage or has perused the various Apogee forums has read that. Quoting it again here provides no new information.
Likewise, it's a complete waste of bandwidth for you to paste Robert Harley's entire Slant 6 test report into a posting here. Anybody can Google that if they so choose.
If you've got something new to offer and/or can answer some questions regarding your various assertions, please do so. Otherwise I'm not sure what your interest is in posting other than just juvenile commentary.
My goodness.
Dave.
You can dial-up something like that with a DSP crossover easily and experiment. Then, you can always duplicate it at speaker-level if you like, or build an analog line-level notch filter. You've got a few options there.
For your Minor project, I see the notch filter as the easiest part of the implementation.
Dave.
I will be using analog throughout. I still have a vinyl front end and not ready (quite yet) to accept that an A/D stage is transparent. Sure I will eventually tho 😉
the notch is only non-trivial as I don't know what the optimal shape is. Apogee I expect had to compromise and until I measure in room response I won't know what I need to get the target response I want.
the notch is only non-trivial as I don't know what the optimal shape is. Apogee I expect had to compromise and until I measure in room response I won't know what I need to get the target response I want.
Bill,
My suggestion awhile back was for you to measure your existing notch filter.....not acoustically, but electrically at the driver terminals. That will at least yield the Apogee engineered response, which you can then work away from......should you so choose.
Anyways, if you want to engineer a notch filter at line-level, an op-based gyrator circuit will work, or possibly a modified shelving filter. It shouldn't be a problem.
I hope Peter returns since we've sort of jacked this thread.....but not very far hopefully. 🙂 I just wanted to point out the error in the schematic he posted in post #1 so he wouldn't proceed with any misinformation.
Cheers,
Dave.
My suggestion awhile back was for you to measure your existing notch filter.....not acoustically, but electrically at the driver terminals. That will at least yield the Apogee engineered response, which you can then work away from......should you so choose.
Anyways, if you want to engineer a notch filter at line-level, an op-based gyrator circuit will work, or possibly a modified shelving filter. It shouldn't be a problem.
I hope Peter returns since we've sort of jacked this thread.....but not very far hopefully. 🙂 I just wanted to point out the error in the schematic he posted in post #1 so he wouldn't proceed with any misinformation.
Cheers,
Dave.
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It's not a problem, just may need iterating or something more complex building to get the response right. Time, money, when is it turd polishing etc.
Nah, that's no fun. I felt dirty enough being tempted to buy a linkwitz ASP board set.
Decided time for action so pulled one of the grilles off. Will take out driver tomorrow and take some pics. Those grilles really cannot help anything. Good news is that I can move up to a 7" driver if I want to. Still agonising over stands or not as that will define if I need to drill a new hole for the driver.
Also wondering about time alignment as wouldn't be hard to move the driver out 2".
Decided time for action so pulled one of the grilles off. Will take out driver tomorrow and take some pics. Those grilles really cannot help anything. Good news is that I can move up to a 7" driver if I want to. Still agonising over stands or not as that will define if I need to drill a new hole for the driver.
Also wondering about time alignment as wouldn't be hard to move the driver out 2".
I can appreciate folks not wanting to go down the DSP route. 🙂 In this case, it's an excellent option because the speakers require no extensive filtering and/or equalization like typical conventional or even some dipole setups. Pretty much generic electrical responses and minimal EQ are going to yield a good result. Such is the robustness of the basic Apogee design that this can be achieved.
Cheers,
Dave.
Cheers,
Dave.
agreed. Although going open baffle on the woofer will make it a bit harder. The response dip at 1KHz will also need addressing.
Dave...
thanks for all your years of your helping others on the web..stay on right path...
An thanks for helping me see what a fool I have been to think anything I new about audio would ever help anyone.
PS. if you would go to the moderator an have all the wasted of bandwidth I have posted... pulled from these pages an others....it the right thing to do....forgive me for ever saying anything neg about you!
Keep up the work
thanks for all your years of your helping others on the web..stay on right path...
An thanks for helping me see what a fool I have been to think anything I new about audio would ever help anyone.
PS. if you would go to the moderator an have all the wasted of bandwidth I have posted... pulled from these pages an others....it the right thing to do....forgive me for ever saying anything neg about you!
Keep up the work
The sarcasm is unnecessary.
I've never gone to a moderator on diyaudio.com to make a complaint about a poster or to request editing of content, and I'm not going to start now. If I have a problem with a person's postings they'll hear about here in the open forum or directly via a PM without a moderator being cc'd.
You may want to read post #103 again and note the part where I comment that you do have some knowledge and good information. When you relate it and don't resort to silly commentary your posts are a valuable asset to this community.
Even though your posts require a lot of effort (for me) to decipher, I find that they occasionally contain some valuable information/experience.
Cheers,
Dave.
I've never gone to a moderator on diyaudio.com to make a complaint about a poster or to request editing of content, and I'm not going to start now. If I have a problem with a person's postings they'll hear about here in the open forum or directly via a PM without a moderator being cc'd.
You may want to read post #103 again and note the part where I comment that you do have some knowledge and good information. When you relate it and don't resort to silly commentary your posts are a valuable asset to this community.
Even though your posts require a lot of effort (for me) to decipher, I find that they occasionally contain some valuable information/experience.
Cheers,
Dave.
Challenges, and there will be some anomalies (off-axis) that you won't be able to correct simply because the baffle is so big. This is inherent in largish speaker systems and can't be avoided. Find a baffle shape that appears to create a fairly even polar response, build it and then measure it.
It's easy to correct response to be flat at a single arbitrary measuring point, but your off-axis response is a key factor in the overall result.
Cheers,
Dave.
That's phase 6! Have been negotiating with memsahib, who has agreed to the plans (including re-comissioning the subwoofer), but only as long as the system stays out of action for minimum time for each phase and, other than ribbons and new amps I fund it all selling other stuff i don't need.
If you look at the stereophile measurements the dip is on axis as well, which is part x-over, part baffle. That at least I can correct. A gedlee style CD this will never be!
If you look at the stereophile measurements the dip is on axis as well, which is part x-over, part baffle. That at least I can correct. A gedlee style CD this will never be!
The off-axis response transition at crossover of a stock Centaur is already dramatic. Almost anything OB can only be a step forward. I always liked Carver's theoretical approach but not his implementation. Multiple twelve inch woofers with weak magnets never felt like the right solution where the bulk of vocals live. He tries to cover too much range.
Attachments
Yes, the Carver's were an interesting design. 🙂 I only heard a pair once and only for a half-hour or so. Some have commented they liked the bass performance of the Carver's, but I didn't find it satisfactory.
Yes indeed, when transitioning from a conventional box woofer to an open-baffle MRT, the transition is abrupt and easily noticeable. This open-baffle bass approach matched to the ribbon driver for this "modified" Centaur HAS to work better. I think it has the potential to be an excellent system.
This approach can translate well to the larger (ribbon woofer) Apogee models as well. Since those are no longer cost effective to repair, inspired users might decide to modify their speakers into this configuration.
Dave.
Yes indeed, when transitioning from a conventional box woofer to an open-baffle MRT, the transition is abrupt and easily noticeable. This open-baffle bass approach matched to the ribbon driver for this "modified" Centaur HAS to work better. I think it has the potential to be an excellent system.
This approach can translate well to the larger (ribbon woofer) Apogee models as well. Since those are no longer cost effective to repair, inspired users might decide to modify their speakers into this configuration.
Dave.
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