They seem to have their own thing going on, interesting..
https://www.martin-audio.com/installation/CDDseries
With my tiny room and ears, SPLs should be non-issue, particularly with >95db drivers like the GPA 416 and Tony Tubby 12" Alnico. For a bi-amped system, would you care to suggest which of those two drivers might be the best with the SEAS T35 tweeter https://www.madisoundspeakerstore.c...-exotic-t35-x3-06-tweeter-with-alnico-magnet/ ?
On the other hand, would a (passively crossed) dedicated midrange driver be required to insure integrity of the critical midrange band? But if not, would other (notch) filtering besides the active crossover still be needed between of the T35 and the TT or the 416?
Gary Dahl, of course, had great success with the 416's in 3 cu. ft. sealed boxes, acoustically cutting their low end off below 70Hz-for his subs to then takeover below that-thereby minimizing distortion. Assuming the TT would work as well or better with the T35 tweeters than would the 416, how low might the TTs go in what sized sealed box with low distortion (in a bi-amped system)?
Lastly, could you suggest any good enclosure design freeware (or payware) for the more knowledgeable newbie?
oltos,
That price for any dome tweeter is insane, I just can't imagine paying anything like that for any dome tweeter. Are you sure that if you are not going to listen at high spl levels that one of the GPA drivers can't be used to cover the entire low frequency range? Unless you really want extreme low bass I think all this talk of needing to get down to 20hz is just more audiophile over the top thinking. If you are in an apartment I will tell you that if you actually produce anything that low you are going to have some very annoyed neighbors.
That price for any dome tweeter is insane, I just can't imagine paying anything like that for any dome tweeter. Are you sure that if you are not going to listen at high spl levels that one of the GPA drivers can't be used to cover the entire low frequency range? Unless you really want extreme low bass I think all this talk of needing to get down to 20hz is just more audiophile over the top thinking. If you are in an apartment I will tell you that if you actually produce anything that low you are going to have some very annoyed neighbors.
Yes, >$500/tweeter is not very DIY friendly. However, we usually get what we pay for. And as popular as Alnico drivers are-particularly at this thread (and with good reason I trust)-its ridiculous that there’s no one in the states making a tweeter that performs as well within its range as the GPA 416 does within its range (and actually a bit more, if I read Lynn Olson, Gary Dahl and James Sheerin correctly).
I certainly don’t know as much as the above members. But when Gary said that he deliberately chose a 3 cu ft closed box to minimize the 416s’ IM distortion-even if it does limit the low end to 70Hz-I knew that I wanted Jim Salk to build me a pair for my bi-amped living room system. And since that 18 ft x 14 ft room allow a reasonable amount of low band range’s wavelengths to propagate, I figured that having Jim also build a pair of his Rythmik 12” sealed servo subs would also make sense. Soundlab’s Roger West is designing the pair of ESL HF/MF drivers to work with the 416s.
But my spare bedroom’s only 12 x 13. I can’t use another pair of Roger’s ESLs; a whole lot pricier than the SEAS T35s. Besides, the ESLs get their DC bias from my amps, and cable length must be kept to minimum. Ironically, that would be a problem in this smaller room. So the T35s make a lot more sense-and cost a lot less cents too.
But I’d also like that system to get to between 35Hz and 30Hz; that’s a good step away from 20Hz, yes? Gary’s boxes will only let the 416s do down to 70Hz (but nice and cleanly). And doubling their size to 6 cu ft in that little room is out of the question.
That’s why I thought of the Tone Tubby Alnicos in sealed boxes crossed with a pair of Rythmik Subs. They claim that by choosing a pair of their F12G subs, which use paper cone drivers from GR Research, that they can be crossed above 80Hz. Rythmik Audio • Servo subwoofer products And bi-amping the T35s and the TTs will make crossing them much easier and with much less distortion.
Questions? Comments? Again, can anyone suggest some closed box speaker design software for the TTs?
Personally I don't believe for a minute that Alnico has that much of an advantage over a Neodymium magnet motor. I haven't looked at the cost lately but I don't think the Revelator dome tweeter will cost as much as you are talking about. For that matter in a small room at lower levels I don't buy the IM distortion argument about the GPA driver, it is another of those audiophile boogeymen. I was just having a conversation with another speaker designer who had much to do with many European speaker developments and he confirmed that the argument about doppler shift and this includes much of that argument about IM distortion is not something that was found in actual double blind listening tests. I personally would just retune the box size for the Gpa drivers and forget about sub woofers in your small room. the fact that you are going to use a smaller 12" driver to supplement the 15" blows that argument about IM distortion out of the water. Of course this is only the opinion of a speaker designer so take it with a grain of salt!
Jim Salk's a few steps from completing my speaker builds. The last time I heard Alnico speakers for sure were in my Bozak years long ago (B-300 series 3-way drivers) powered by less than ideal amps (Lafayette receiver), and probably equally less favorable acoustics. My living room system will be very different in every way. But as for Alnico drivers, I merely read everything Gary Dahl and Lynn Olson had posted about them at this thread. They have loads of measuring, listening and design expertise with numerous other midwoofers and woofers, horns, ESLs, et al. In short, I’m no expert, they are. I merely followed their lead.
But what of our alnico versus ferrite or ceramic or neodymium debate? Again, coming from a member who’s clearly an experienced designer The Art of Speaker Design Lynn Olson makes a very good case-and based on what he said he ACTUALLY heard from the 416s http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-781.html
But this magnet debate is really a non-issue. What matters most is how well I will be able to blend the T35s with the driver below it. To this end-whether or not its alnico magnet is a contributing factor-the 416 seems to be an extraordinarily good-if very surprising option, given its 15” cone. Nevertheless, as Lynn mentioned: “The Altec/GPA 416 and 515 are some of the very few drivers I can think of that can do this; they also have very smooth rolloffs above 1.5 kHz, and don't need the usual prosound brickwall filtering.”
And so, from the SEAS T35’s FR curve and one can seem to easily conclude that it and the 416 will be almost a snap to blend together, especially if bi-amped, as I’m doing.
Yes, of course I would love to scratch the subs, but I do want between 35Hz and 30Hz. Smaller boxes for the 416s could definitely work if I ported them, but I strongly suspect that I much prefer the sound of sealed woofers (no wonder I missed my Bozaks after I foolishly sold them).
So the only way to get down to the 30s in sealed boxes is to build relatively large ones. But how large? Probably no less than 5 cu ft-and that’s interior volume; exterior would be a bit larger. With proper bracing and adding the same front-panel rounded corners that Gary (and I) did to minimize diffraction distortion, figure at least another 3” or so more. So please, not in that little room.
That’s why I thought to use the 12” Tone Tubbys: They’d cross with the paper coned Rythmik sealed subs at around 100Hz. And they would cross just as well, if not better with the T35s than the 416s would (though I was hoping for someone’s reply to confirm this).
I heard that Gary Dahl was recently holding guest listening sessions. I’m on Long Island and I don’t fly.
But if you do, why not check it out?
But what of our alnico versus ferrite or ceramic or neodymium debate? Again, coming from a member who’s clearly an experienced designer The Art of Speaker Design Lynn Olson makes a very good case-and based on what he said he ACTUALLY heard from the 416s http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-781.html
But this magnet debate is really a non-issue. What matters most is how well I will be able to blend the T35s with the driver below it. To this end-whether or not its alnico magnet is a contributing factor-the 416 seems to be an extraordinarily good-if very surprising option, given its 15” cone. Nevertheless, as Lynn mentioned: “The Altec/GPA 416 and 515 are some of the very few drivers I can think of that can do this; they also have very smooth rolloffs above 1.5 kHz, and don't need the usual prosound brickwall filtering.”
And so, from the SEAS T35’s FR curve and one can seem to easily conclude that it and the 416 will be almost a snap to blend together, especially if bi-amped, as I’m doing.
Yes, of course I would love to scratch the subs, but I do want between 35Hz and 30Hz. Smaller boxes for the 416s could definitely work if I ported them, but I strongly suspect that I much prefer the sound of sealed woofers (no wonder I missed my Bozaks after I foolishly sold them).
So the only way to get down to the 30s in sealed boxes is to build relatively large ones. But how large? Probably no less than 5 cu ft-and that’s interior volume; exterior would be a bit larger. With proper bracing and adding the same front-panel rounded corners that Gary (and I) did to minimize diffraction distortion, figure at least another 3” or so more. So please, not in that little room.
That’s why I thought to use the 12” Tone Tubbys: They’d cross with the paper coned Rythmik sealed subs at around 100Hz. And they would cross just as well, if not better with the T35s than the 416s would (though I was hoping for someone’s reply to confirm this).
I heard that Gary Dahl was recently holding guest listening sessions. I’m on Long Island and I don’t fly.
But if you do, why not check it out?
Oltos, I don't think that expensive dome tweeter is a good match for the 416, 515, or similar old-school high-efficiency driver. True, they both have Alnico magnets, but the similarities end there. For one thing, I wouldn't cross any 1" dome tweeter at 1.5 kHz, no matter how wonderful it is reputed to be. Direct-radiator dome tweeters have OK dynamics at best, and crossing them that low asks far too much excursion from them. You can add a waveguide in front of them, but that's a whole new project.
I enjoy the old Scan-Speaks I have in the Ariels, but their dynamics are not remotely in the same class as 416s, 515s, or modern prosound 15" drivers ... and I have the Scan-Speaks crossed at 3.8 kHz. I would never cross them at 2 kHz, no matter what the specs say. And I would have very mixed feelings about taking a 416-class driver to 2 kHz.
Long story short, I see a coverage gap between a 416-class driver and any 1" dome tweeter ... at least two octaves, and maybe a bit more. That's ignoring the substantial differences in headroom, efficiency, and dispersion at the crossover frequency. I don't see any way around that, except for using a custom-designed waveguide and appropriate EQ in the crossover. A horn, in other words.
Some people have had success with AMT-type HF drivers combined with 15" midbass drivers, but I have not heard this combination for myself, except for a brief listen to Gary Pimm's restored AMT speakers. My initial impression of AMT's is they might make interesting supertweeters to complement MF/HF horns, but the region from 1~5 kHz needs a little work. Again, waveguides are probably the solution.
I enjoy the old Scan-Speaks I have in the Ariels, but their dynamics are not remotely in the same class as 416s, 515s, or modern prosound 15" drivers ... and I have the Scan-Speaks crossed at 3.8 kHz. I would never cross them at 2 kHz, no matter what the specs say. And I would have very mixed feelings about taking a 416-class driver to 2 kHz.
Long story short, I see a coverage gap between a 416-class driver and any 1" dome tweeter ... at least two octaves, and maybe a bit more. That's ignoring the substantial differences in headroom, efficiency, and dispersion at the crossover frequency. I don't see any way around that, except for using a custom-designed waveguide and appropriate EQ in the crossover. A horn, in other words.
Some people have had success with AMT-type HF drivers combined with 15" midbass drivers, but I have not heard this combination for myself, except for a brief listen to Gary Pimm's restored AMT speakers. My initial impression of AMT's is they might make interesting supertweeters to complement MF/HF horns, but the region from 1~5 kHz needs a little work. Again, waveguides are probably the solution.
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oltos,
Don't get hung up over the alnico thing. The vast majority of audio systems do not have the resolution needed to hear the difference between magnetic materials. it is much more important to choose the best drivers to cover a particular frequency range. Most drivers do not sound their best when used at their published frequency extremes. The Altec 515 ( I use a pair in a front loaded horn )and 416's are best mid bass drivers available IMHO--but don't push them out of their comfort zone. The 416's will go a little lower than the 515's but don't have quite the " snap" and dynamics.
The Altec woofers are a natural mate for horns. You can get a reasonable size horn / waveguide from DIY Sound Group to mate up with a Beyma, Faital, B & C etc. compression drivers to cover the critical midrange ( around 500hz to 4 or 5kz. ). Your woofer will be happy to cover below 500hz. and your tweeter will be happy to cover the top end. You can easily mount the horn / tweeter on top of your bass cabinet. Just my 2 cents--good luck.
Also, check out John Inlow's site for more good information.
Don't get hung up over the alnico thing. The vast majority of audio systems do not have the resolution needed to hear the difference between magnetic materials. it is much more important to choose the best drivers to cover a particular frequency range. Most drivers do not sound their best when used at their published frequency extremes. The Altec 515 ( I use a pair in a front loaded horn )and 416's are best mid bass drivers available IMHO--but don't push them out of their comfort zone. The 416's will go a little lower than the 515's but don't have quite the " snap" and dynamics.
The Altec woofers are a natural mate for horns. You can get a reasonable size horn / waveguide from DIY Sound Group to mate up with a Beyma, Faital, B & C etc. compression drivers to cover the critical midrange ( around 500hz to 4 or 5kz. ). Your woofer will be happy to cover below 500hz. and your tweeter will be happy to cover the top end. You can easily mount the horn / tweeter on top of your bass cabinet. Just my 2 cents--good luck.
Also, check out John Inlow's site for more good information.
Oltos, I might have been a little too dismissive of 15" woofer + 1" dome concept in the previous post. One guide to possible speaker systems is what was done in the Fifties, when top-of-the-line speakers pretty much always had a 15" woofer in the lineup.
* Altec and Stephens Tru-Sonic combined a 15" woofer with MF/HF horn/compression driver in their domestic speakers. The selling point of the Stephens was a multicell horn for the HF, which was unusual, maybe unique for a domestic speaker.
* JBL and Klipsch sold systems with a 15" woofer, MF horn, and HF horn. The Klipsch could be bought in a basshorn-only version, and I personally heard systems built around a Klipsch basshorn, a theater-grade multicell horn for MF, and the famed Ionovac tweeter for the HF/VHF.
* Bozak sold direct-radiator (no horns) systems built around 15" Bozak woofers and arrays of the unique Bozak 2" cone tweeter (a predecessor to the famed Peerless HFC225 cone tweeter). The top-of-the-line system had a one, two, or four (!) 15" woofers, the advanced Bozak 6" midrange, and a good-sized array of Bozak cone tweeters. I never heard the large-format Bozak, but they were highly regarded at the time.
If horns/waveguides ain't your thing, you could build yourself a modern-day Bozak system. The Audax PR170 is the only modern driver I can think of that's kind of like the Bozak midrange, but maybe the exotic French drivers with field-coil magnets (PHY?) might be of interest.
I have no idea what a 416, PR170 or PHY mid, and Scan-Speak 1" dome tweeter would sound like. It would be expensive, more expensive than the proven Gary Dahl speaker, and a jump into the unknown. My intuition tells me the dome tweeter would not have the spectacular dynamics of the 416, and good subjective integration of the mid could prove very difficult. My vague memory of the PR170 is a somewhat forward and brash presentation, which is quite different than the lush and vivid 416/515 sound. Mids are notoriously hard to integrate with LF and HF drivers ... that's why there are so many disjointed-sounding high-end speakers on the market. Poor choice of mid and poor system integration.
Equalization can match up the gross tonality of the drivers, but it doesn't change the underlying "personality" of the driver. You still hear that through the EQ. My experience is that it's always best to use the driver in it's "best" range, taking advantage of what it does well, and using the crossover to remove as much as possible the less-desirable aspects of performance. I've yet to hear a driver with no personality at all; they all have a distinct sound, and the trick with a multiway system is finding a harmonious combination of personalities. Kind of like a good band or a memorable dinner.
Part of the charm of the 416 (and 515) is a hornlike presentation, in terms of dynamics and vividness of tone color. By comparison, dome tweeters are much drabber and flatter sounding, no matter how expensive ... diamond, ceramic, Kevlar, metal, silk, what have you. They all sound like dome tweeters, compared to a ribbon, AMT, or horn mid/tweeter. All four types have radically different presentations, and are strong and weak in different parts of the spectrum.
P.S. If you want to try something really different, get a pair of Janzen Z130 or RTR tweeters, and put them in the throat of pair of 24" or larger Tractrix or LeCleac'h horns. I heard a setup like that years ago, and was very impressed with the dynamics, snap, and vivid tone colors. It didn't sound like a wimpy electrostat at all. Now that would be an interesting match to a 416 woofer.
* Altec and Stephens Tru-Sonic combined a 15" woofer with MF/HF horn/compression driver in their domestic speakers. The selling point of the Stephens was a multicell horn for the HF, which was unusual, maybe unique for a domestic speaker.
* JBL and Klipsch sold systems with a 15" woofer, MF horn, and HF horn. The Klipsch could be bought in a basshorn-only version, and I personally heard systems built around a Klipsch basshorn, a theater-grade multicell horn for MF, and the famed Ionovac tweeter for the HF/VHF.
* Bozak sold direct-radiator (no horns) systems built around 15" Bozak woofers and arrays of the unique Bozak 2" cone tweeter (a predecessor to the famed Peerless HFC225 cone tweeter). The top-of-the-line system had a one, two, or four (!) 15" woofers, the advanced Bozak 6" midrange, and a good-sized array of Bozak cone tweeters. I never heard the large-format Bozak, but they were highly regarded at the time.
If horns/waveguides ain't your thing, you could build yourself a modern-day Bozak system. The Audax PR170 is the only modern driver I can think of that's kind of like the Bozak midrange, but maybe the exotic French drivers with field-coil magnets (PHY?) might be of interest.
I have no idea what a 416, PR170 or PHY mid, and Scan-Speak 1" dome tweeter would sound like. It would be expensive, more expensive than the proven Gary Dahl speaker, and a jump into the unknown. My intuition tells me the dome tweeter would not have the spectacular dynamics of the 416, and good subjective integration of the mid could prove very difficult. My vague memory of the PR170 is a somewhat forward and brash presentation, which is quite different than the lush and vivid 416/515 sound. Mids are notoriously hard to integrate with LF and HF drivers ... that's why there are so many disjointed-sounding high-end speakers on the market. Poor choice of mid and poor system integration.
Equalization can match up the gross tonality of the drivers, but it doesn't change the underlying "personality" of the driver. You still hear that through the EQ. My experience is that it's always best to use the driver in it's "best" range, taking advantage of what it does well, and using the crossover to remove as much as possible the less-desirable aspects of performance. I've yet to hear a driver with no personality at all; they all have a distinct sound, and the trick with a multiway system is finding a harmonious combination of personalities. Kind of like a good band or a memorable dinner.
Part of the charm of the 416 (and 515) is a hornlike presentation, in terms of dynamics and vividness of tone color. By comparison, dome tweeters are much drabber and flatter sounding, no matter how expensive ... diamond, ceramic, Kevlar, metal, silk, what have you. They all sound like dome tweeters, compared to a ribbon, AMT, or horn mid/tweeter. All four types have radically different presentations, and are strong and weak in different parts of the spectrum.
P.S. If you want to try something really different, get a pair of Janzen Z130 or RTR tweeters, and put them in the throat of pair of 24" or larger Tractrix or LeCleac'h horns. I heard a setup like that years ago, and was very impressed with the dynamics, snap, and vivid tone colors. It didn't sound like a wimpy electrostat at all. Now that would be an interesting match to a 416 woofer.
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Note: with respect to the T35..
I once had a discussion on the fullrange forum with someone that took a chance on this tweeter and I believe was quite pleased with the result.
Oddly, it was their (seas) alnico fullrange driver that he wasn't pleased with - where he decided on the Supravox 285, and was *very* pleased with that driver (in conjunction with the seas T35).
Of course the Supravox is an 8" driver with a very different directivity pattern below about 1.4 kHz when compared to a 15" driver.
..might want to consult Dave Pellegrene about a larger custom low-depth waveguide to accompany the T35:
acoustic waveguides
For a lot less money you might want to also look at his results for the Audax TW025A28 and the heil-type AC AST2560:
https://plus.google.com/101632266659473725850/posts/8zZNxPfVVmA
I once had a discussion on the fullrange forum with someone that took a chance on this tweeter and I believe was quite pleased with the result.
Oddly, it was their (seas) alnico fullrange driver that he wasn't pleased with - where he decided on the Supravox 285, and was *very* pleased with that driver (in conjunction with the seas T35).
Of course the Supravox is an 8" driver with a very different directivity pattern below about 1.4 kHz when compared to a 15" driver.
..might want to consult Dave Pellegrene about a larger custom low-depth waveguide to accompany the T35:
acoustic waveguides
For a lot less money you might want to also look at his results for the Audax TW025A28 and the heil-type AC AST2560:
https://plus.google.com/101632266659473725850/posts/8zZNxPfVVmA
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Well there you go. Combine an Altec/GPA 416 with the Supravox 285 and the Seas T35. All direct-radiator, no horns, and exotic magnets, as desired. Use the 285 in a small, well-damped closed-box of its own, or use an OB the same width as the closed (or vented) box for the 416.
Set the crossover between the 416 and the 285 between 300 and 500 Hz, the 285 and T35 crossover around 3 kHz, and attenuate the Supravox 285 several dB so it sits midway between the 416 (97.5 dB/meter/watt) and T35 (94 dB/metre/watt) in efficiency. (A slightly down-sloping response is desirable.) With an enclosure as large as the 416 will require, little or no Baffle Step Compensation will be necessary.
If you want to get really fancy, attenuate the Supravox 285 with a custom-made autoformer from Dave Slagle, instead of an L-pad. The Altex/GPA 416 and Seas T35 will have no attenuation, of course.
Done.
Set the crossover between the 416 and the 285 between 300 and 500 Hz, the 285 and T35 crossover around 3 kHz, and attenuate the Supravox 285 several dB so it sits midway between the 416 (97.5 dB/meter/watt) and T35 (94 dB/metre/watt) in efficiency. (A slightly down-sloping response is desirable.) With an enclosure as large as the 416 will require, little or no Baffle Step Compensation will be necessary.
If you want to get really fancy, attenuate the Supravox 285 with a custom-made autoformer from Dave Slagle, instead of an L-pad. The Altex/GPA 416 and Seas T35 will have no attenuation, of course.
Done.
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It is good to be reading some new angles on getting a good sound. I mean it is about listening nirvana - is it not?
Rules is rules but rules are made to be broken - aren't they ?
Kings rule but they always seemed to changed the rules with each succession.
It is easy to throw huge amounts of money at the objective. Let the manufacturers of speaker systems do that for the oil sheiks.
You could take cheapos in all sections and make something that is virtually unsurpassable.
The compression tweeter is a dome driver with a phase plug. It suffers from Charles Law (yes we know that Van der Waal plussed him) if that matters to you
A comparison of the tweeter efficiencies of the Scan-Speaks used in the Ariel (91 dB/watt/meter) versus the Seas T35 (94 dB/watt/meter) tells you why I got lost in the wilderness of horns for several years. It just wasn't worth designing an entire new speaker for a measly 3 dB efficiency gain ... and no real gain in headroom at all.
3 dB is nice, of course, but I wanted more like 6 to 8 dB more efficiency, and at least 10 dB gain in headroom. And that pretty much goes straight to horns. Fortunately, Bjørn Kolbrek was available to do the heavy lifting of designing and mathematically modeling what became the Azura Ah425. Without LeCleac'h, Bjørn, and Martin Seddon of Azurahorn, it wouldn't have possible. The thanks really goes to them.
As for bass, a single direct-radiator 416 is good for 97.5 dB, a pair is good for 100.5 dB (with a 6 dB gain in headroom), and a basshorn is good for 103 to 106 dB (with a headroom gain of more than 10 dB). The choice is yours.
(See the last pages of the "My Island Speaker" thread for info on the version with the Inlow 135 Hz basshorn. I have no doubt it is a superb loudspeaker. Space restrictions will probably limit me to a dual-woofer version.)
3 dB is nice, of course, but I wanted more like 6 to 8 dB more efficiency, and at least 10 dB gain in headroom. And that pretty much goes straight to horns. Fortunately, Bjørn Kolbrek was available to do the heavy lifting of designing and mathematically modeling what became the Azura Ah425. Without LeCleac'h, Bjørn, and Martin Seddon of Azurahorn, it wouldn't have possible. The thanks really goes to them.
As for bass, a single direct-radiator 416 is good for 97.5 dB, a pair is good for 100.5 dB (with a 6 dB gain in headroom), and a basshorn is good for 103 to 106 dB (with a headroom gain of more than 10 dB). The choice is yours.
(See the last pages of the "My Island Speaker" thread for info on the version with the Inlow 135 Hz basshorn. I have no doubt it is a superb loudspeaker. Space restrictions will probably limit me to a dual-woofer version.)
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Thanks hottatoo, but I’m betting that my electronics will actually have that degree of resolution to make those distinctions. I’ll be bi-amping (or at least partly, if I need to use 3 drivers beyond a pair of Rythmik subs) both of my speakers systems with Nelson Pass’s B4 active crossover (all JFETs). One system will be driven by his J2 amp and F4 amps; the other system by two F4s. All of this hardware are like most of Nelson’s designs; extremely stable, DC coupled with zero feedback. The F4s are unusual as they are voltage followers. So a kind and very experienced soul here at the Pass Labs forum is building for me Nelson’s BA-3 line stage (the single-end configuration) for each F4 amp. I know some of the sharpest and most experienced users-and designers-on this thread would have little, if anything to do with SS amps. But Nelson Pass’s designs are very exceptional, to say the least. Read about how the goals he sought were achieved by an approach to design that in many ways is akin to that of at least some of the very best tube amps. http://www.firstwatt.com/articles.html Still, I know one or two here who say that Pass amps just don’t agree with them.
I won’t be going DAC shopping until the rest of my speakers and the BA-3s are built, but I have recently compiled a fairly short list of pricey but still affordable models to choose from.
So I think there’s a great likelihood that my electronics will have the ability to tell and Alnico from a ceramic with ease. Which is probably a big reason why Jon Ver Halen had teamed up with Nelson for many years.
http://www.lowther-america.com/Cabinets/Open_Baffle_Speakers/Large_Open_Baffle/ Those are First Watt amps bi-amping Jon’s large OBs, with GPA Altec 416s.
Honestly, the Altec 4Xs, 5Xs and/or A7s were probably the only horn systems I’ve ever heard. That was way back in the last years of our beloved Syosset Theatre (before those goons from the Oyster Bay Town Board and a posse of real estate philistines razed it http://www.in70mm.com/news/2003/syosset/ ) As one who loved the big grand houses as much for their sound as for seeing some of old movie favorites on the big screen, I do recall being very impressed with what I heard-at least compared what I little I ever heard even at the big local retailers of the times, like Syosset’s Laffayette (they also sold lots of parts for DIYers) and Woodbury’s somewhat higher end Harvey Radio. If anyone on Long Island had something like the Altec Valencias it was Harvey, but can’t recall seeing them there. Sadly, even when I’d make trips to NYC I never did stop into Sound By Singer, Stereo Exchange or the other state-of-the-art audio dealers.
The Syosset was a big theatre; almost as big as the Calderon in Hempstead (now a church), where my father saw Ben Hur. So to be sure (?) that the lows had room to really propagate could have been a big part of why I was so awestruck when we saw the Sound of Music and so other big features. Compared to what gear at had at home, I probably could help but be impressed with the highs and mids of those old Altec horns, though I also think remember finding them to be shrill at least some of the time. The Syosset used Ampex amps; I don’t know how well designed they were, so that may have been a factor. But I’ve read here or at other forums that those particular horns had fairly high distortion.
However, just because there’s no one hear on Long Island selling horn systems (and our DIY audio community here died out many years ago) doesn’t mean I’d dismiss wanting to build one. I’m especially intrigued by Lynn Olson’s idea about putting Janzen Z130 or RTR tweeters (aren’t they out of production?) in the throat of pair of 24" or larger Tractrix or LeCleac'h horns-and cross those with a pair of GPA Altec 416s. See my reply to Lynn below on that.
Too bad that I don’t fly, as I’ll probably never get to hear Gary Dahl’s system. But thanks to his generosity, I was able to do the next best thing. Check out my replies to Lynn on that too.
Excuse all of my reminiscing, but maybe you enjoyed it as much as I.
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Thanks Lynn for all the tremendously valuable feedback-particularly the cautionary info, asI could have wasted lots of time and money on the two systems I’m building without your guidance. But first, the system for my spare bedroom: That room’s only 12 ft x 13; kind of
laughable proportions to be spending serious money and effort on, I suppose. But does this also mean that it’s pointless to build a system that can get down to between 35 and 30Hz? If not, then clicking on each link at this page http://www.rythmikaudio.com/technology.html , I’d really appreciate your assessment of each of the design aspects of this particular 12” sealed servo sub.
Not only does this design seem to place it among the very best powered commercial subs around, but I reasoned that if I didn’t EQ it to go down below 35Hz to 30Hz, that distortion-including up to its usable high end band-would be further minimized.
Btw, I don’t Bozak ever used 15” woofers. They were all 12” alnicos. These guys have the 1958 catalog, http://www.preservationsound.com/?p=5804 but you may have problems downloading it.
Also, Rythmik does make the same sealed sub and servo electronics in a 15” version. However, designer Brian Ding-and Jim Salk, who builds his own improved cabinets for Rythmik drivers-assured me that a pair of 12” subs would easily fill even my 14 ft by 18 living room and that the 15” would just play louder.
As for above 100Hz, just as my bedroom is probably too small for passive 15” sealed woofers-including Gary’s 26” wide sealed Altec 416 midwoofers-how about the Tone Tubby 12” Alnico as a substitute for the 416? I see here http://www.nutshellhifi.com/MLS/MLS6.html that you heard and measured it in an open baffle. Though it may have sounded wonderful in OBs, placed in a large enough room, would the TTs low end be extended to as low as 100Hz to 80Hz in a sealed box? If yes, then the paper coned Rythmiks’ crossovers should have no trouble blending with them, yes?
But to get an undistorted 100Hz to 80Hz range (70Hz?) out of the TTs, can you estimate what size sealed box I’d need?
Now for the highs: Would the TTs blend well with the SEAS T35 tweeter
https://www.madisoundspeakerstore.com/seas-soft-dome-tweeters/seas-exotic-t35-x3-06-tweeter-with-alnico-magnet/ -particularly if it was fitted with this waveguide http://www.troelsgravesen.dk/TQWT-DTQWT-mkII-T35.htm ?
Alternatively, I recall reading that you were very fond of RAAL ribbons. Would the TTs work as well or better than the T35-wth a particular model RAAL ribbon, in my small room? If yes, please recommend the best applicable model https://www.madisoundspeakerstore.com/index.php?p=catalog&mode=search&search_in=all&search_str=raal And would they be easy to cross with the TTs, especially since I’m bi-amping?
Lastly, in your review of the TT, you stressed its superb midrange. Were it otherwise,would your driver of choice to cross above the TT be Rob Mackinlay’s mini ESLs http://www.eraudio.com.au/Mini_Panels/mini_panels.html ? Indeed, as you say here
http://www.nutshellhifi.com/library/speaker-design1.html , nothing touches the midrange quality of ESLs. Of course, their highs probably don’t extend to where the RAAL ribbons can go.
OR might there be a horn to use above TT that you think I’d like better than any of the above drivers-even a RAAL ribbon? However, please bear in mind that the only horn systems I can ever recall hearing were the Altec A-4X, A-5X and/or A-7 back in the 80s here
http://www.in70mm.com/news/2003/syosset/ Needless, to say, if those horns had the sizable distortion issues that I might have read about, Gary’s horns and those you strongly recommend certainly must sound better by magnitudes.
So which of all these HF drivers would you choose to work with the sealed TTs in my tiny
room?
Thanks Scott for this great feedback on the T35. Could it have been the SEAS W8 that he didn't like https://www.madisoundspeakerstore.com/approx-8-woofers/seas-exotic-w8-x2-08-8-woofer-alnico-magnet/ ?
I refer to that waveguide for the T35, ribbon HF drivers and the GPA Altec 416 in my reply to Lynn-and will do so in greater depth with the 416 later on regarding my living room system.
Agreed, though FWIW, the older 515s were as smooth, clear in its breakup modes BW out to a rolled off ~5 kHz as so called 'full-range' drivers of the day, so combined with the 800 series 1" exit compression driver's built in ~5 kHz round conic HF wave guide that only needs a round over mouth termination/> 2.7" dia. baffle, folks built compact high efficiency two ways for some apps or as 'starter' systems where they could add a mids driver/horn as budget/space permitted.
Driven with a ~matching impedance SET amp, the late, great 'ultralight' alum. diaphragm 802 AlNiCo driver is about as 'sweet'/extended a HE option as it gets short of maybe a tiny Fostex or similar 'super' tweeter when limited to 5 kHz/2nd order and still well above average at moderate power with 1st order, though in a conversation with the late JMMLC, he and some of his audio buddies considered the Beryllium TAD just a 'hair' 'sweeter'/extended than the 802G, but hard to justify the extra cost unless it wasn't an issue.
Sadly, the 'ultralight' is decades long gone and if you see some for sale or claimed to be loaded in drivers, don't waste your money as they will be work hardened/brittle by now, so any perceived 'sweetness' it may have will just be increased HF distortion.
That said, some with both claim that GPA's replacement diaphragm is at least as good and has higher power handling to boot, so another reason not to be tempted with 'vintage' sales hype.
Bottom line, you want a matching 'super' tweeter to most vintage Altec/GPA [mid] bass drivers, one need look no further than the AlNiCo 802 and preferably the 802G combined with GPA diaphragms or the Beryllium TAD for max HF extension.
Also, if some recent response plots I've seen were properly done, then GPA can 'close enough' replicate the early 515B's HF response, though i imagine only by request since it's not needed for later 515 series apps and without an A/B comparison with mine, no clue how close they will audibly perform.
GM
GM,
I don't remember the model number and don't want to open up my untouched Altec Barcelona speakers but in that cabinet they used an air suspension 15" that worked well in a sealed enclosure. I don't know if anyone ever duplicated that speaker but it would seem in a smaller two way sealed alignment that could be another approach to a two way with a 15" and horn or something else above that device. The box isn't exactly small but isn't really that large compared to the entire enclosure as it is sub-divided for the horn above. Just a suggestion that I don't know is even possible today.
I don't remember the model number and don't want to open up my untouched Altec Barcelona speakers but in that cabinet they used an air suspension 15" that worked well in a sealed enclosure. I don't know if anyone ever duplicated that speaker but it would seem in a smaller two way sealed alignment that could be another approach to a two way with a 15" and horn or something else above that device. The box isn't exactly small but isn't really that large compared to the entire enclosure as it is sub-divided for the horn above. Just a suggestion that I don't know is even possible today.
411-8A and GPA offers the later version with more durable surround, so still an option for very low output impedance driven sealed systems such as yours and its 9846, 9848 studio monitor variants: 9846-8A
9848
Recommended optimum alignment is 5 ft^3 sealed: http://www.lansingheritage.org/images/altec/plans/1974-enc-design/page12.jpg
GM
9848
Recommended optimum alignment is 5 ft^3 sealed: http://www.lansingheritage.org/images/altec/plans/1974-enc-design/page12.jpg
GM
Thanks for that GM. I have to say that considering how simple the network is and I think the 511 horn with a 1" driver with I think the symbiotic diaphragms they still sound pretty good for a 40 year old design. Mine actually still have the original surrounds, they have never been exposed to any sun light and seem to still be in good shape, no crumbling foam at this point.
As I say I don't want to mess with them, they are just so classic and the cabinets are still virtually perfect after all these years.
If I was Oltos I would take a serious look at that 15" driver and then he could forget about having to add a sub in such a small room. They make plenty of low bass. And it would be real simple to find a small horn to go with them and perhaps a more modern 1" driver and a much more thoughtful network to go with the system.
Just my two cents on that.
As I say I don't want to mess with them, they are just so classic and the cabinets are still virtually perfect after all these years.
If I was Oltos I would take a serious look at that 15" driver and then he could forget about having to add a sub in such a small room. They make plenty of low bass. And it would be real simple to find a small horn to go with them and perhaps a more modern 1" driver and a much more thoughtful network to go with the system.
Just my two cents on that.