Charivari
Fighting Naïve Realism
I am a fan of planar dipole speakers. Doesn't get simpler than that and have enjoyed playing with various planar-magnetic, quasi-ribbon, and true ribbon designs over the past few years.
My dream speakers have been of such designs, such as the quasi-ribbon line array Infinity IRS V...
... but it's obviously priced out of my reach for the foreseeable century. Even for my practical dream speakers, the comparatively compact Infinity IRS Beta, I've yet to find a pair for less than 2x the price of my primary transportation and more often several times as much.
So, there I was dreaming of these great speakers and making do with what I could scrounge from here or there. I played with other "high end" vintage speakers that others rave about including Bozaks, Tannoy dual-concentrics, Altec A7-500s, and so on, but even the best still lacked that certain something my first good speakers, a pair of Magnepan MG-Is had despite their shortcomings of veiling and limited frequency extension. So, I decided to stop my path into more boxes and horns and return to my planar roots.
With some hunting and lots of luck, I managed to pick up a pair of Flatline Design Model 175s[url] that with their 69" long pseudo-true ribbon driver (set up like a true ribbon, but with a kapton backed element) promised a hint of what the big IRS Vs could offer.
[URL=http://i30.photobucket.com/albums/c301/jpvanson/Flatline%20Designa/Flatline.jpg]
Trouble is, they were hybrids. Excellent speakers as far as the ribbon element ran, but soon as the midbass kicked in, there were serious integration issues. Even lower in frequency, a 5" point source monopole cone cannot blend well with a 69" line source dipole ribbon. So close, but yet so far. I still wasn't satisfied with the sound and knew that this was nowhere close to what the big Infinities would sound like.
So, in a fit of frustration, I hacked into the Flatlines' crossovers a bit, removing the cone and sticking in my rather similar impedance Magnepan MG-I bass panels in place of the midbass. It was an ugly setup with loads of issues, but there it was, there was that something missing. Though a lousy frankenstein setup, the dipoles were blending well and the 10" woofer and a separate DIY sub of mine were filling in the bottom. The bass was still fairly poor as even a good acoustic suspension design doesn't blend well with a planar panel. So, I jury-rigged a passive line level crossover, removed the Flatlines' 10" woofer from the system, and ran the Watkins woofers in my ex-Infinity Quantum 2s. Now I was getting somewhere and more closely approximating the IRS -- I even had an Infinity in the system. Effectively stacking a planar panel beside a kapton-backed ribbon with conventional cone woofers was nothing new --Infinity did it and later Apogee even did it with Grand -- so I knew I wasn't chasing my tail on this. Somewhere along the line, Kelly (kfa888) saw a picture of them and somewhat deridingly declared them my "frankenribbons" and the name stuck.
This was the sound I wanted, but much improvement was needed. The Magnepan panels were blocked by the Flatlines' towers and the Infinities that space required to have partially behind. Moving the Quantum 2s out helped open up the sound, though at the cost of having to go back to the less than great sub. The Magnepan baffle also extended some distance from edge of the driver making for a rather smeared image. The reflection of the ribbons' output reflecting off the Magnepan panels reduced the soundstage to between the speakers and smeared the imaging all the more. Then there was the disparity in height between the 5' tall Magnepan panels and the ribbons making the seated position the only decent listening position. Tonally, it sounded very good, but everything else was suffering for it, but I had an idea.
The solution seemed simple enough, go purely dipole planar from 30Hz-44kHz, make sure the panels were similar in vertical height to the ribbons, remove any boxes from the primary channel speakers even for support, and set the planar panels in line with the ribbons to minimize interfering reflections and time align them at the same time. I also wanted to move the cone bass down in frequency as far as I practically could to optimize the coherence of the system and to allow me to move the bass unit to wherever was practical in my oddly shaped apartment living/listening room. I found some inspiration in an old The Absolute Sound article where Harry Pearson described his own frankensteined type quasi-ribbon/planar project in the QRS-1D.
The QRS-1D was an attempt to improve the coherency of the Infinity QRS (Quantum Reference Standard), the IRS progenitor, between the 15" Watkins woofer and the Strathern built quasi-ribbon midranges.
Someone's DIY QRS-1D:
The result was supposed to be a significant improvement and apparently solved the midbass dip issues the big Infinities have. The Tympani bass panels solved the same issues I was finding with my own creation, offered better sound, and provided another link to the big Infinity IRS. Now, I had an idea where to head and I needed Tympani bass panels.
After a year of searching and several failed deals, I finally managed to find a pair of Magnepan Tympani IUs. Better yet, they had been rebuilt in the past two decades to have ID bass panels. The best, the price was just manageable for me and they were local, so no shipping. So, I brought them home, set them up, and hung the Flatlines ribbons off the side such that the ribbon is exactly in line with the bass panels. The Tympani bass panels when connected in series were within a fraction of an ohm match to the impedance of the original Flatline midbass driver. So, I took the crossovers from the Flatlines, pulled the Zobel from the midbass network, and connected the Tympanis through that. The resulting frankenribbons had the Tympani bass panels operating in the entire bass and midbass range up to 350Hz where the Flatlines' ribbons took over in a 6dB/oct slope on up to their own 44kHz limit. Taking a bit of a hint from Sound Labs on how to avoid beaming issues with large planars, I took advantage of the hinged connections between the panels and put a slight curve in the whole thing.
Firing the contraption up, I was mightily impressed by the sound. A bit of matching in levels between the amps, as I now have to run them biamped, cleaned up the sound and tonal balance all the more. After several days of listening to them, I knew I had something good, but I didn't want to deceive myself. So, I invited an audio enthusiast friend of mine, who has heard my main system in its various iterations, over for a Saturday listening session. What was supposed to be a couple hours worth of album spinning resulted in his being glued to the listening seat until the early morning hours, camping out on the couch for the night, and continuing more listening the rest of the day. Neither of us could quit throwing on old favorite albums and new selections and listen to them all the way through. Even when the amp on the ribbons melted from the load and constant play, we threw a spare on and kept listening. Though a mighty picky person when it comes to audio, and oft full of criticism for my main system, he gave the frankenribbons a glowing review and declared them the best sound he'd ever heard. This despite my seemingly doing everything wrong for good sound and the system sounding far better than it should using conventional audiophile wisdom. Considering that we've both listened to some very high end systems, including one half-million dollar Wilson/Halcro setup, I consider it high praise.
I have to agree, they were sounding very good. Trying to avoid my biases for my own creation, I realize that they have far to go and could use an improved crossover, room treatments, and better positioning to smooth out the bass response. Yet, they are a joy to listen to. Until I can ever find myself a pair of big Infinities, these will likely remain my main speakers that I'll continue to tweak and try to improve on. Currently, the Tympani bass panels are only down ~4dB at 30Hz and I have my DIY sub crossing in there to handle the rest of the spectrum flat down to 20Hz (with usable output to 16Hz in its position). The sub does use a passive radiator and with its high group delay still does not blend well. So, I'll continue my quest to eventually build a stereo pair of subwoofers or even bass towers if I can swing it. For now, as an apartment dweller, I'm satisfied with the Frankenribbons.
Well, outside of cosmetics, that is. For the majority who automatically perceive a good looking component as sounding far better than an ugly component, the Frankenribbons look dreg and that they should just as bad. Even I will admit that even I would hear them as sounding better had they nice grained, polished wood everywhere and a name brand attached. So, I'll need to work on that as I can and replace the socks on the panels I had removed them on to accomplish some repairs.
Here they are, the horrendously ugly, but fantastically musical Frankenribbons:
6' tall, 37.5" wide, they are the antithesis of the minimonitor fetish. Oddly enough, they seem to work best 7' into the room and near the walls to minimize bass cancellation by creating a phantom baffle extending to infinity on the outside. These are planars with room shaking bass and the subwoofer in the picture only helps add a bit more rumble.
Well, that was much longer than I had intended, but so be it. At least this post is a summary of the dozens of pages worth of thought and design changes that went into these.
- JP
My dream speakers have been of such designs, such as the quasi-ribbon line array Infinity IRS V...
... but it's obviously priced out of my reach for the foreseeable century. Even for my practical dream speakers, the comparatively compact Infinity IRS Beta, I've yet to find a pair for less than 2x the price of my primary transportation and more often several times as much.
So, there I was dreaming of these great speakers and making do with what I could scrounge from here or there. I played with other "high end" vintage speakers that others rave about including Bozaks, Tannoy dual-concentrics, Altec A7-500s, and so on, but even the best still lacked that certain something my first good speakers, a pair of Magnepan MG-Is had despite their shortcomings of veiling and limited frequency extension. So, I decided to stop my path into more boxes and horns and return to my planar roots.
With some hunting and lots of luck, I managed to pick up a pair of Flatline Design Model 175s[url] that with their 69" long pseudo-true ribbon driver (set up like a true ribbon, but with a kapton backed element) promised a hint of what the big IRS Vs could offer.
[URL=http://i30.photobucket.com/albums/c301/jpvanson/Flatline%20Designa/Flatline.jpg]
Trouble is, they were hybrids. Excellent speakers as far as the ribbon element ran, but soon as the midbass kicked in, there were serious integration issues. Even lower in frequency, a 5" point source monopole cone cannot blend well with a 69" line source dipole ribbon. So close, but yet so far. I still wasn't satisfied with the sound and knew that this was nowhere close to what the big Infinities would sound like.
So, in a fit of frustration, I hacked into the Flatlines' crossovers a bit, removing the cone and sticking in my rather similar impedance Magnepan MG-I bass panels in place of the midbass. It was an ugly setup with loads of issues, but there it was, there was that something missing. Though a lousy frankenstein setup, the dipoles were blending well and the 10" woofer and a separate DIY sub of mine were filling in the bottom. The bass was still fairly poor as even a good acoustic suspension design doesn't blend well with a planar panel. So, I jury-rigged a passive line level crossover, removed the Flatlines' 10" woofer from the system, and ran the Watkins woofers in my ex-Infinity Quantum 2s. Now I was getting somewhere and more closely approximating the IRS -- I even had an Infinity in the system. Effectively stacking a planar panel beside a kapton-backed ribbon with conventional cone woofers was nothing new --Infinity did it and later Apogee even did it with Grand -- so I knew I wasn't chasing my tail on this. Somewhere along the line, Kelly (kfa888) saw a picture of them and somewhat deridingly declared them my "frankenribbons" and the name stuck.
This was the sound I wanted, but much improvement was needed. The Magnepan panels were blocked by the Flatlines' towers and the Infinities that space required to have partially behind. Moving the Quantum 2s out helped open up the sound, though at the cost of having to go back to the less than great sub. The Magnepan baffle also extended some distance from edge of the driver making for a rather smeared image. The reflection of the ribbons' output reflecting off the Magnepan panels reduced the soundstage to between the speakers and smeared the imaging all the more. Then there was the disparity in height between the 5' tall Magnepan panels and the ribbons making the seated position the only decent listening position. Tonally, it sounded very good, but everything else was suffering for it, but I had an idea.
The solution seemed simple enough, go purely dipole planar from 30Hz-44kHz, make sure the panels were similar in vertical height to the ribbons, remove any boxes from the primary channel speakers even for support, and set the planar panels in line with the ribbons to minimize interfering reflections and time align them at the same time. I also wanted to move the cone bass down in frequency as far as I practically could to optimize the coherence of the system and to allow me to move the bass unit to wherever was practical in my oddly shaped apartment living/listening room. I found some inspiration in an old The Absolute Sound article where Harry Pearson described his own frankensteined type quasi-ribbon/planar project in the QRS-1D.
The QRS-1D was an attempt to improve the coherency of the Infinity QRS (Quantum Reference Standard), the IRS progenitor, between the 15" Watkins woofer and the Strathern built quasi-ribbon midranges.
Someone's DIY QRS-1D:
The result was supposed to be a significant improvement and apparently solved the midbass dip issues the big Infinities have. The Tympani bass panels solved the same issues I was finding with my own creation, offered better sound, and provided another link to the big Infinity IRS. Now, I had an idea where to head and I needed Tympani bass panels.
After a year of searching and several failed deals, I finally managed to find a pair of Magnepan Tympani IUs. Better yet, they had been rebuilt in the past two decades to have ID bass panels. The best, the price was just manageable for me and they were local, so no shipping. So, I brought them home, set them up, and hung the Flatlines ribbons off the side such that the ribbon is exactly in line with the bass panels. The Tympani bass panels when connected in series were within a fraction of an ohm match to the impedance of the original Flatline midbass driver. So, I took the crossovers from the Flatlines, pulled the Zobel from the midbass network, and connected the Tympanis through that. The resulting frankenribbons had the Tympani bass panels operating in the entire bass and midbass range up to 350Hz where the Flatlines' ribbons took over in a 6dB/oct slope on up to their own 44kHz limit. Taking a bit of a hint from Sound Labs on how to avoid beaming issues with large planars, I took advantage of the hinged connections between the panels and put a slight curve in the whole thing.
Firing the contraption up, I was mightily impressed by the sound. A bit of matching in levels between the amps, as I now have to run them biamped, cleaned up the sound and tonal balance all the more. After several days of listening to them, I knew I had something good, but I didn't want to deceive myself. So, I invited an audio enthusiast friend of mine, who has heard my main system in its various iterations, over for a Saturday listening session. What was supposed to be a couple hours worth of album spinning resulted in his being glued to the listening seat until the early morning hours, camping out on the couch for the night, and continuing more listening the rest of the day. Neither of us could quit throwing on old favorite albums and new selections and listen to them all the way through. Even when the amp on the ribbons melted from the load and constant play, we threw a spare on and kept listening. Though a mighty picky person when it comes to audio, and oft full of criticism for my main system, he gave the frankenribbons a glowing review and declared them the best sound he'd ever heard. This despite my seemingly doing everything wrong for good sound and the system sounding far better than it should using conventional audiophile wisdom. Considering that we've both listened to some very high end systems, including one half-million dollar Wilson/Halcro setup, I consider it high praise.
I have to agree, they were sounding very good. Trying to avoid my biases for my own creation, I realize that they have far to go and could use an improved crossover, room treatments, and better positioning to smooth out the bass response. Yet, they are a joy to listen to. Until I can ever find myself a pair of big Infinities, these will likely remain my main speakers that I'll continue to tweak and try to improve on. Currently, the Tympani bass panels are only down ~4dB at 30Hz and I have my DIY sub crossing in there to handle the rest of the spectrum flat down to 20Hz (with usable output to 16Hz in its position). The sub does use a passive radiator and with its high group delay still does not blend well. So, I'll continue my quest to eventually build a stereo pair of subwoofers or even bass towers if I can swing it. For now, as an apartment dweller, I'm satisfied with the Frankenribbons.
Well, outside of cosmetics, that is. For the majority who automatically perceive a good looking component as sounding far better than an ugly component, the Frankenribbons look dreg and that they should just as bad. Even I will admit that even I would hear them as sounding better had they nice grained, polished wood everywhere and a name brand attached. So, I'll need to work on that as I can and replace the socks on the panels I had removed them on to accomplish some repairs.
Here they are, the horrendously ugly, but fantastically musical Frankenribbons:
6' tall, 37.5" wide, they are the antithesis of the minimonitor fetish. Oddly enough, they seem to work best 7' into the room and near the walls to minimize bass cancellation by creating a phantom baffle extending to infinity on the outside. These are planars with room shaking bass and the subwoofer in the picture only helps add a bit more rumble.
Well, that was much longer than I had intended, but so be it. At least this post is a summary of the dozens of pages worth of thought and design changes that went into these.
- JP
