It was a warm, busy day in Rocklin California yesterday, for the DIY Speaker meet which Mark K. hosted at his home. We had a pretty good sized turn-out, over 30 attendees altogether, with quite a few bringing projects, some quite sizable, to share with the other attendees. Mark also had his garage open and a flea market speaker sale/swap operation going, so this took a little of the pressure off the listening room.
I brought most of the electronics and interconnects used for auditioning the systems, so with characteristic candor, it was suggested that I go first, just to make sure everything works and we didn't make any smoke. Of course, my own speaker was the only one I didn't get a picture of while running around and setting up, so I'll substitute this reminder here.
There were some kind comments, and interest in the details of the Vifa XT crossover, as well as suprise at the performance on cuts like Jame's Taylor's Gaia- "you've got a sub hooked up, right?" No. Also, there were numerous comments on how nice these new PE enclosures looked.
Jim led off the three systems he brought with his "Modins". These are an MTM built in a Speaker City enclosure, using the same crossover as Joe D'Apollito developed for the Thor TL system for the low pass, but with Morel tweeters and his own crossover for the high pass. Jim is willing to share details about his design. For these and most of the other smaller systems, we did connect at their request Mark's sealed Tempest sub through the Delilah II crossover and Aragon 8008 X3.
DIY_JimS%20Modin.jpg
The Modins cranked out a very clear, high def sound typical of good implementations of with the Seas Excel Mag woofers, and the Morel tweeters acquitted themselves quite nicely, too.
Jim also brought two smaller systems, one using a SS Revelator woofer and Usher tweeter.
DIY_JimS%20User-Rev.jpg
The Revelator woofer is well known, but the Usher tweeter proved that it is quite worthy to follow in SS's footsteps, especially considering the value proposition.
Jim's last system combined a 5" Revelator with a HiVi ribbon tweeter.
This system was quite petite, and in the sweet spot, exhibited very nice sound. The narrow vertical axis does limit ceiling bounce, but also mandates careful speaker and listener positioning.
Brian's sealed 1801 variants were uniformly regarded as the nicest finished speakers at the meet; he obtained some nice rosewood over Ebay, but the amount limited the size he could cover, and led him to make a smaller sealed variant of the 1801, using the Seas 7" Excel woofer and the Hiqaphon tweeter.
The sound was very clear and transparent, quite similar in many regards to Jim's Modins. Again, the sub and crossover was added to flesh out the bottom end a bit.
Ratch, who teaches physics in high school, brought one of his students and her three way project, using a HiVi 8" woofer, a Vifa midrange originally made for Infinity, and a Vifa XT tweeter. Crossovers were first order, and the sound was very impressive for her first speaker project.
DIY%20Student3Way.jpg
Next up were Jame's modified Linus array. He tested and evaluated a number of alternative 5" drivers, ultimately selecting a Vifa model, and modifying the array by extending the tweeter elements for a taller listening window. The driver and box combination is ported, with a tuning to 50 Hz. The multiple drivers allow rather high output and good reproduction of the "room space" of the original recording. Listening distance is somewhat critical, as the midrange and highs are a very effective line source, and in a high celing room, the bass isn't propagated with a reflected LF image, so the overall balance is optimal at one listening distance.
Dave brought a 2.5 way system with all Vifa drivers, beautifuly finished with maple. This system had a very warm and full sound, and nice dynamics. It should be noted that all systems were demo's at about 3 feet from the rear wall, due to space limitations for audience seating. For some systems, this is too close to the wall, depending on baffle step compensation employed; for others, it was too far away.
Next was a two way with active low sub was still a little bit of a work in progress, and was hampered by one of the LF drivers in the bottom cabinet having been damaged just days ago. However, it still produced very clear smooth sound, with good integration of two way section and nice dynamics.
DIY_2Way%2BSub.jpg
One of the more talked about and thought provoking set of speakers was David Ortega's K-Line using a full range Hartley driver, an Audax tweeter to augmetn the highs above 12 kHz (OK, so not so full range), and two Theil modified ScanSpeak drivers to augment the bottom end. The unusual side wall and mouth construction, per Forsman, is said to provide an acoustic load which the drivers work into, and which then loads into the room (hope I got that straight). Forsman claims that this allows the drivers to respond 30-40% faster- in engineering terms this would equate with a faster rise time, and more extended frequency response. Yes, you may be saying to yourself, that's a bit reminiscent of a Karlson horn- my first thoughts too.
They had a very different presentation than most of the other speakers at the meet, and reminded me somewhat of an older Altec theater system driven by original Western Electric amplifiers. A very "vintage" kind of sound. Dave hasn't finished tuning the system, as they were completed just prior to the meet.
Dan C brought an interesting set of Budget HT speakers he'd developed, using Pioneer TV speakers which were actually given away by PE to anyone willing to make a system they could promote with them. Apparently, the effort was not trivial, but after considerable crossover development, in combination with an MCM tweeter that costs less than the binding posts I usually use, he produced a pretty remarkable sound for next to nothing. Now, if Dan had to factor in his development time labor to the cost, we're looking at a $7K pair of speakers!
Next up was the demo which had many folks waiting with bated breath- George brought his Linkwitz Orion system, built with Aksa 50W and 100 watt amps from Australia, and Siegfried himself gave an explanation of the concepts and development issues.
Siegfried brought some excellent demo material, and that plus the inherent high performance of the Orion system clearly set the high water mark for acoustical peformance at the meet. The Modin's were close in the lower mids through top end, but the Orion's were very well balanced and articulate through out the entire range, from moderately low bass on up.
The Orion's were a tough act to follow, but Paul K was up to the challenge, bringing his four way TL system which used first order crossovers with a combination of parallel and series networks. The dome mid was a LPG unit, with a vifa metal tweeter with diffusor.
His contruction was attractive and modern with an interesting textured finish. The bevelled grilles he built were very nicely done, also.
Pauls system is usually used against the wall, so the sound in the listening position was a little lighter than normal, but very well defined and integrated through the whole range.
Following Paul was a two way system with built in subs using a horn mid-tweeter assembly which goes out to 16 kHz. Though in the early stages of development, on Keb Mo it should some interesting potential, and was probably the efficiency champ of the meet.
This was another one of the systems that we had to resort to the Delilah II and second amplifier in order to provide LF power, but this time to the built in Peerless sub in each cabinet.
Next, Ratch displayed his three way system instead of one of his students; the first cabinet had been built for some time, but reportedly the second was finished in the wee hours of Saturday morning. This sysem features a combination of Vifa drivers, including a special "unobtanium" version of a vifa midrange, and SS tweeter, in a folded TL enclosure (yes, lot's of TL's at this meet- and this wasn't the last of 'em.)
The sound was clear, full, and quite deep in the bass on the selection of classical cuts Ratch played for us.
Did I mention more TL's? (this is like a blast to the past for me, as I built my last TL's in the 70's). Our affable, hard working host Mark K (see below)
demo'd his three way TL's also. Now, I recall Mark making some comments a couple of months ago about how he expected that there would be some stragglers coming in with crossovers with parts hanging off, and alligator clips connecting everything together. I don't think we expected he would be one of them! His three way with a Scan Speak kevlar woofer, Morel dome mid, and Hiqaphon tweeter is built into an enclosure design based on Martin Kings concepts for a mass loaded quarter wave transmission line. This concept "appears" to be a specific configuration using what appears to be a bass reflex port, but with some specific requirements for the cabinet proportions, driver positioning, and port tuning, in a quarter wave column. Oddly enough, after discussing the design with him, I realize that my M8ta project essentially uses the same configuration... what a conincidence. I'll have to see if it models using Martin's MathCAD model.
As Mark pointed out, his choice of drivers and crossover points results in very broad dispersion and frequency response through out the whole range, very uniform almost to 90 degrees off axis. With some coils exhibiting a higher DCR than he expected, the baffle step compensation didn't work out quite as planned, but nevertheless the deep bass was pretty astounding for a single 8 inch driver, and the system was very open and dynamic. With a little more tweaking, he'll certainly have something pretty special here.
While we were "tearing down", we continued to listen to Mark's system, but with a tube amplifier which Cyrix brought up for Mark to audition. This proved to be interesting- were the changes in sound due to impedance interaction with the speaker and the amplifier output impedance, or due to a fundamentally different tonality? We didn't have time to investigate, but I think Mark will.
A tiring but very interesting day....
Regards,
Jon
Earth First!
_______________________________
We'll screw up the other planets later....
I brought most of the electronics and interconnects used for auditioning the systems, so with characteristic candor, it was suggested that I go first, just to make sure everything works and we didn't make any smoke. Of course, my own speaker was the only one I didn't get a picture of while running around and setting up, so I'll substitute this reminder here.
There were some kind comments, and interest in the details of the Vifa XT crossover, as well as suprise at the performance on cuts like Jame's Taylor's Gaia- "you've got a sub hooked up, right?" No. Also, there were numerous comments on how nice these new PE enclosures looked.
Jim led off the three systems he brought with his "Modins". These are an MTM built in a Speaker City enclosure, using the same crossover as Joe D'Apollito developed for the Thor TL system for the low pass, but with Morel tweeters and his own crossover for the high pass. Jim is willing to share details about his design. For these and most of the other smaller systems, we did connect at their request Mark's sealed Tempest sub through the Delilah II crossover and Aragon 8008 X3.
DIY_JimS%20Modin.jpg
The Modins cranked out a very clear, high def sound typical of good implementations of with the Seas Excel Mag woofers, and the Morel tweeters acquitted themselves quite nicely, too.
Jim also brought two smaller systems, one using a SS Revelator woofer and Usher tweeter.
DIY_JimS%20User-Rev.jpg
The Revelator woofer is well known, but the Usher tweeter proved that it is quite worthy to follow in SS's footsteps, especially considering the value proposition.
Jim's last system combined a 5" Revelator with a HiVi ribbon tweeter.
This system was quite petite, and in the sweet spot, exhibited very nice sound. The narrow vertical axis does limit ceiling bounce, but also mandates careful speaker and listener positioning.
Brian's sealed 1801 variants were uniformly regarded as the nicest finished speakers at the meet; he obtained some nice rosewood over Ebay, but the amount limited the size he could cover, and led him to make a smaller sealed variant of the 1801, using the Seas 7" Excel woofer and the Hiqaphon tweeter.
The sound was very clear and transparent, quite similar in many regards to Jim's Modins. Again, the sub and crossover was added to flesh out the bottom end a bit.
Ratch, who teaches physics in high school, brought one of his students and her three way project, using a HiVi 8" woofer, a Vifa midrange originally made for Infinity, and a Vifa XT tweeter. Crossovers were first order, and the sound was very impressive for her first speaker project.
DIY%20Student3Way.jpg
Next up were Jame's modified Linus array. He tested and evaluated a number of alternative 5" drivers, ultimately selecting a Vifa model, and modifying the array by extending the tweeter elements for a taller listening window. The driver and box combination is ported, with a tuning to 50 Hz. The multiple drivers allow rather high output and good reproduction of the "room space" of the original recording. Listening distance is somewhat critical, as the midrange and highs are a very effective line source, and in a high celing room, the bass isn't propagated with a reflected LF image, so the overall balance is optimal at one listening distance.
Dave brought a 2.5 way system with all Vifa drivers, beautifuly finished with maple. This system had a very warm and full sound, and nice dynamics. It should be noted that all systems were demo's at about 3 feet from the rear wall, due to space limitations for audience seating. For some systems, this is too close to the wall, depending on baffle step compensation employed; for others, it was too far away.
Next was a two way with active low sub was still a little bit of a work in progress, and was hampered by one of the LF drivers in the bottom cabinet having been damaged just days ago. However, it still produced very clear smooth sound, with good integration of two way section and nice dynamics.
DIY_2Way%2BSub.jpg
One of the more talked about and thought provoking set of speakers was David Ortega's K-Line using a full range Hartley driver, an Audax tweeter to augmetn the highs above 12 kHz (OK, so not so full range), and two Theil modified ScanSpeak drivers to augment the bottom end. The unusual side wall and mouth construction, per Forsman, is said to provide an acoustic load which the drivers work into, and which then loads into the room (hope I got that straight). Forsman claims that this allows the drivers to respond 30-40% faster- in engineering terms this would equate with a faster rise time, and more extended frequency response. Yes, you may be saying to yourself, that's a bit reminiscent of a Karlson horn- my first thoughts too.
They had a very different presentation than most of the other speakers at the meet, and reminded me somewhat of an older Altec theater system driven by original Western Electric amplifiers. A very "vintage" kind of sound. Dave hasn't finished tuning the system, as they were completed just prior to the meet.
Dan C brought an interesting set of Budget HT speakers he'd developed, using Pioneer TV speakers which were actually given away by PE to anyone willing to make a system they could promote with them. Apparently, the effort was not trivial, but after considerable crossover development, in combination with an MCM tweeter that costs less than the binding posts I usually use, he produced a pretty remarkable sound for next to nothing. Now, if Dan had to factor in his development time labor to the cost, we're looking at a $7K pair of speakers!
Next up was the demo which had many folks waiting with bated breath- George brought his Linkwitz Orion system, built with Aksa 50W and 100 watt amps from Australia, and Siegfried himself gave an explanation of the concepts and development issues.
Siegfried brought some excellent demo material, and that plus the inherent high performance of the Orion system clearly set the high water mark for acoustical peformance at the meet. The Modin's were close in the lower mids through top end, but the Orion's were very well balanced and articulate through out the entire range, from moderately low bass on up.
The Orion's were a tough act to follow, but Paul K was up to the challenge, bringing his four way TL system which used first order crossovers with a combination of parallel and series networks. The dome mid was a LPG unit, with a vifa metal tweeter with diffusor.
His contruction was attractive and modern with an interesting textured finish. The bevelled grilles he built were very nicely done, also.
Pauls system is usually used against the wall, so the sound in the listening position was a little lighter than normal, but very well defined and integrated through the whole range.
Following Paul was a two way system with built in subs using a horn mid-tweeter assembly which goes out to 16 kHz. Though in the early stages of development, on Keb Mo it should some interesting potential, and was probably the efficiency champ of the meet.
This was another one of the systems that we had to resort to the Delilah II and second amplifier in order to provide LF power, but this time to the built in Peerless sub in each cabinet.
Next, Ratch displayed his three way system instead of one of his students; the first cabinet had been built for some time, but reportedly the second was finished in the wee hours of Saturday morning. This sysem features a combination of Vifa drivers, including a special "unobtanium" version of a vifa midrange, and SS tweeter, in a folded TL enclosure (yes, lot's of TL's at this meet- and this wasn't the last of 'em.)
The sound was clear, full, and quite deep in the bass on the selection of classical cuts Ratch played for us.
Did I mention more TL's? (this is like a blast to the past for me, as I built my last TL's in the 70's). Our affable, hard working host Mark K (see below)
demo'd his three way TL's also. Now, I recall Mark making some comments a couple of months ago about how he expected that there would be some stragglers coming in with crossovers with parts hanging off, and alligator clips connecting everything together. I don't think we expected he would be one of them! His three way with a Scan Speak kevlar woofer, Morel dome mid, and Hiqaphon tweeter is built into an enclosure design based on Martin Kings concepts for a mass loaded quarter wave transmission line. This concept "appears" to be a specific configuration using what appears to be a bass reflex port, but with some specific requirements for the cabinet proportions, driver positioning, and port tuning, in a quarter wave column. Oddly enough, after discussing the design with him, I realize that my M8ta project essentially uses the same configuration... what a conincidence. I'll have to see if it models using Martin's MathCAD model.
As Mark pointed out, his choice of drivers and crossover points results in very broad dispersion and frequency response through out the whole range, very uniform almost to 90 degrees off axis. With some coils exhibiting a higher DCR than he expected, the baffle step compensation didn't work out quite as planned, but nevertheless the deep bass was pretty astounding for a single 8 inch driver, and the system was very open and dynamic. With a little more tweaking, he'll certainly have something pretty special here.
While we were "tearing down", we continued to listen to Mark's system, but with a tube amplifier which Cyrix brought up for Mark to audition. This proved to be interesting- were the changes in sound due to impedance interaction with the speaker and the amplifier output impedance, or due to a fundamentally different tonality? We didn't have time to investigate, but I think Mark will.
A tiring but very interesting day....
Regards,
Jon
Earth First!
_______________________________
We'll screw up the other planets later....
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