Newbie Speaker Build: Part 1
Thanks but I've decided to go with what seems the safest, easiest and, I would certainly think, best sounding: the 416s in 4cf sealed boxes. And because Jeff Bagby's calculator shows an Fc of only ~ 53.68Hz, subs are definitely on the menu. I'll cross that bridge later, though I wonder what weight and footprint are g3dahl's 18" sealed subs. Above the 416Bs, for me I think its something like this Alnico https://www.madisoundspeakerstore.c...-exotic-t35-x3-06-tweeter-with-alnico-magnet/ They're obviously expensive for a pair, but if others here think that these really do both the midrange and the highs superbly, then they might make passively or actively biamping my system easier. Or maybe separate alnico tweets and mids. Too early in the process to say.
Thanks but I've decided to go with what seems the safest, easiest and, I would certainly think, best sounding: the 416s in 4cf sealed boxes. And because Jeff Bagby's calculator shows an Fc of only ~ 53.68Hz, subs are definitely on the menu. I'll cross that bridge later, though I wonder what weight and footprint are g3dahl's 18" sealed subs. Above the 416Bs, for me I think its something like this Alnico https://www.madisoundspeakerstore.c...-exotic-t35-x3-06-tweeter-with-alnico-magnet/ They're obviously expensive for a pair, but if others here think that these really do both the midrange and the highs superbly, then they might make passively or actively biamping my system easier. Or maybe separate alnico tweets and mids. Too early in the process to say.
I don't have 18" sealed subs -- each of my subs consists of a 5 cf enclosure with a TD15H woofer on the front panel and a 15" passive radiator on each side. The PR's are 700 grams each. Box tuning is 23 Hz. Outer dimensions of the sub cabinet are about 20.25" (H) x 25.5" (W) x 22" (D).
Acoustic Elegance no longer carries the passive radiators, so duplicating the design isn't an option. But there are many ways to build good subwoofers with easily-available parts.
Gary Dahl
Acoustic Elegance no longer carries the passive radiators, so duplicating the design isn't an option. But there are many ways to build good subwoofers with easily-available parts.
Gary Dahl
Newbie Speaker Build: Part 1
And would that be your sub's second best low frequency point?
Why exactly did you use the PRs rather than a reflex enclosure? Because you like the sound of them compared to that of a possibly “chuffing” ported sub? And sealed subs, despite their typically superior distortion and transient response, would have required too much wpc, and/or other issues?
Did you have any trouble overcoming the PR's Fr notch, as discussed here Passive radiator (speaker) - Wikipedia, the free encyclopedia
Just curious, what does each one of your finished subs weigh?
And about how many wpc might it take to have them work properly in a 17” x 13 x 7 room?
It seems ironic that a sealed box any bigger than the 4 cf you advise for the 416Bs will make their bass actually sound "thin". Why would that happen?
In any case, the least IM distortion and the best transient response out of my 416Bs the better, so 4 cf it is.
But you added that "reducing the Q a bit could be beneficial".That's the Final Effective Qtc (from Jeff Bagby's calculator)? And that's done by increasing the damping-that is, approaching but not exceeding "critical damping"? Damping - Wikipedia, the free encyclopedia
(omg, that math!) And since more damping to reduce Qtc via a sealed box volume beyond 4 cf is obviously not good for the 416B, then the only other way to increase damping would be to stuff the box, yes?
Is this mostly accomplished by gluing or stapling fiberglass to the opposite box walls? I asked Great Plains tech support if a triangular or polygonal (sealed) box is the best way to prevent standing waves (ring nodes?), but they said all you need do is apply fiberglass to the opposite walls. Yes?
Btw, is there really any substantial sonic value for making the shape of the sealed box for the Altec 416Bs or for the subs something other than square or rectangular?
In any case, what's the best material for stuffing the box? How do I affix it to the walls? How much of it do I use for a 4 cf box?
Once my 416Bs are installed (and most of system crossover scheme is worked out), my trouble will still likely be that I won't have the room for sub boxes bigger than 4 cf; 3 cf would be ideal, though probably a poor choice for sonically, and may all but defeat the purpose of a sub, at least with a passive design. So while I know that the very thought is likely anathema to most here, please express your complete opinion of this solution Rythmik Audio servo subwoofer 12" F12G This 12” sealed Class AB powered servo sub has a paper cone (I recall that you don’t like anything aluminum). As the ear is less sensitive to distortion as well as frequency towards the end points of the audio frequency range, I’m not too concerned about using a plate amp to drive subs-and the design of these seem better than most Rythmik Audio • Subwoofer plate amplifiers And I’ve yet to read a disparaging word about the sound of Rythmik subs (not that others can’t sound better, of course). Has anyone here?
But what Brian Ding and Enrico Castagnetti have stated repeatedly in written replies is that their 15” versions only play louder; they don’t go any deeper-though they offer 2db more efficiency, which may or may reduce plate amp distortion ever so minutely Rythmik Audio 15" servo driver• DS1500 Direct Servo driver (but I don’t want the aluminum cone). So I thought of a pair of the same 12” model above. Of course, while Brian does seem to cover all the bases with his servo controlled solution Rythmik Audio • Servo subwoofer products (click on Technology on left side of home page), which, if perfectly executed, might deliver all of the benefits of a sealed sub, with little, if any, of its drawbacks. However, a thorough critique of his approach would be extremely helpful for making this very crucial decision. Would you please?
Thanks for these facts. So if the box's Fc is 23Hz does that mean that the "half power point" (where output drops by 3db) is at about what frequency?
And would that be your sub's second best low frequency point?
Why exactly did you use the PRs rather than a reflex enclosure? Because you like the sound of them compared to that of a possibly “chuffing” ported sub? And sealed subs, despite their typically superior distortion and transient response, would have required too much wpc, and/or other issues?
Did you have any trouble overcoming the PR's Fr notch, as discussed here Passive radiator (speaker) - Wikipedia, the free encyclopedia
Just curious, what does each one of your finished subs weigh?
And about how many wpc might it take to have them work properly in a 17” x 13 x 7 room?
It seems ironic that a sealed box any bigger than the 4 cf you advise for the 416Bs will make their bass actually sound "thin". Why would that happen?
In any case, the least IM distortion and the best transient response out of my 416Bs the better, so 4 cf it is.
But you added that "reducing the Q a bit could be beneficial".That's the Final Effective Qtc (from Jeff Bagby's calculator)? And that's done by increasing the damping-that is, approaching but not exceeding "critical damping"? Damping - Wikipedia, the free encyclopedia
(omg, that math!) And since more damping to reduce Qtc via a sealed box volume beyond 4 cf is obviously not good for the 416B, then the only other way to increase damping would be to stuff the box, yes?
Is this mostly accomplished by gluing or stapling fiberglass to the opposite box walls? I asked Great Plains tech support if a triangular or polygonal (sealed) box is the best way to prevent standing waves (ring nodes?), but they said all you need do is apply fiberglass to the opposite walls. Yes?
Btw, is there really any substantial sonic value for making the shape of the sealed box for the Altec 416Bs or for the subs something other than square or rectangular?
In any case, what's the best material for stuffing the box? How do I affix it to the walls? How much of it do I use for a 4 cf box?
Once my 416Bs are installed (and most of system crossover scheme is worked out), my trouble will still likely be that I won't have the room for sub boxes bigger than 4 cf; 3 cf would be ideal, though probably a poor choice for sonically, and may all but defeat the purpose of a sub, at least with a passive design. So while I know that the very thought is likely anathema to most here, please express your complete opinion of this solution Rythmik Audio servo subwoofer 12" F12G This 12” sealed Class AB powered servo sub has a paper cone (I recall that you don’t like anything aluminum). As the ear is less sensitive to distortion as well as frequency towards the end points of the audio frequency range, I’m not too concerned about using a plate amp to drive subs-and the design of these seem better than most Rythmik Audio • Subwoofer plate amplifiers And I’ve yet to read a disparaging word about the sound of Rythmik subs (not that others can’t sound better, of course). Has anyone here?
But what Brian Ding and Enrico Castagnetti have stated repeatedly in written replies is that their 15” versions only play louder; they don’t go any deeper-though they offer 2db more efficiency, which may or may reduce plate amp distortion ever so minutely Rythmik Audio 15" servo driver• DS1500 Direct Servo driver (but I don’t want the aluminum cone). So I thought of a pair of the same 12” model above. Of course, while Brian does seem to cover all the bases with his servo controlled solution Rythmik Audio • Servo subwoofer products (click on Technology on left side of home page), which, if perfectly executed, might deliver all of the benefits of a sealed sub, with little, if any, of its drawbacks. However, a thorough critique of his approach would be extremely helpful for making this very crucial decision. Would you please?
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Once compromised, exploit the compromise.
Hoffman's iron law remains. If you've only got a few cubic feet and you're trying to match high efficiency mains you're not going to do that passively. So stop trying and exploit the opportunity to add some more watts "down there".
Eg. the old Adire Audio "Shiva" used to manage 90db/w, corner loaded, in a 3cf sealed box (Q=0.6, -3db 30Hz to 80Hz - ish). And could do 105db at 29Hz, free space.
Once you are in a "small" room then max spl levels rapidly rise - Adire claimed 105db @ 15.4Hz for the 0.6 sealed alignment in the corner of a 5 x 4.5 x 2.3m room. But that's against a 1W level of c. 85db - you will need both 100W of real power and EQ against the 3db point at 30Hz.
Group delay issues have been discussed in this thread
The Shiva is just an example that I happen to have numbers for (from "SHIVA SEALED CABINET APPLICATIONS" 2000 Adire Audio.) - I am certain there
Hoffman's iron law remains. If you've only got a few cubic feet and you're trying to match high efficiency mains you're not going to do that passively. So stop trying and exploit the opportunity to add some more watts "down there".
Eg. the old Adire Audio "Shiva" used to manage 90db/w, corner loaded, in a 3cf sealed box (Q=0.6, -3db 30Hz to 80Hz - ish). And could do 105db at 29Hz, free space.
Once you are in a "small" room then max spl levels rapidly rise - Adire claimed 105db @ 15.4Hz for the 0.6 sealed alignment in the corner of a 5 x 4.5 x 2.3m room. But that's against a 1W level of c. 85db - you will need both 100W of real power and EQ against the 3db point at 30Hz.
Group delay issues have been discussed in this thread
The Shiva is just an example that I happen to have numbers for (from "SHIVA SEALED CABINET APPLICATIONS" 2000 Adire Audio.) - I am certain there
Here is the simulation that I worked from:
As you can see, F3 is only 43 Hz, but it works out pretty well when the room gain is taken into account. The woofer has enough excursion to allow some EQ for a lower -3dB point if desired. The DSP in my home theater equipment (when in use) takes great advantage of this.
See the following link: AE Speakers Passive Radiator FAQ
No, the notch frequency is low enough to not be a concern (see FAQ).
No idea. I can carry one for a reasonable distance, but it's not fun. The hand truck is my friend. I don't have any idea how I could weigh a subwoofer. You're welcome to drop by and try it.
My room is a bit bigger. The plate amps powering my subs are rated to deliver 250W to the 4-ohm TD15H woofers. During yesterday's listening session they knocked the stuffing out of us. Honestly I had no idea that they could do this. It was kind of fun but a bit scary.
Go to MH-Audio Closed Box Calculator, play with the values and look at the resulting response. The response shape changes to a higher Q value as the box volume decreases, and a lower Q as the volume increases. Typically, woofers of this size intended for sealed enclosures will tune to a much lower frequency, but at lower efficiency. The 416 was of course designed for vented enclosures tuned to a lower frequency. However, in a lucky coincidence, it also works well in a sealed enclosure at high efficiency. The tuning isn't all that low, but a subwoofer (or two) easily takes care of that.
Damping is increased by reducing the Q, whether by increasing enclosure size or adding stuffing, or a combination of the two. From my point of view, definitely do not exceed critical damping. I prefer a value somewhat higher. I think it's a room-dependent thing, and subject to your preference.
I prefer to stuff the box anyway, so it makes sense to account for that when deciding upon box volume. Any bracing inside the box subtracts from the volume, as also does the air displaced by the driver itself. Then you add the stuffing, which in effect increases the volume again, and suppresses internal standing waves at the same time.
Before bracing and stuffing, my boxes started out at 3 cf. The Q is on the high side, so the sound is on the rich side. I like it that way. Others might not, so I recommend 4 cf. If it is too lean after stuffing, put some blocks of wood inside to reduce the effective volume. Or build the box smaller in the first place.
That is correct if you are building a vented box. If you are building a sealed box, use stuffing.
Standing waves will develop between opposite walls. If different pairs of walls have similar distances, they will develop standing waves at the same frequencies. The significance of this effect depends upon the actual frequencies being produced in the box relative to its dimensions. A stuffed sealed box is less vulnerable to these effects than a vented box because the stuffing suppresses the standing waves.
I prefer Bonded Logic's UltraTouch insulation. Fill the enclosure but don't compress the material. Leave a bit of breathing room around the driver. Just put it in there; it doesn't get attached to anything.
Looks great to me.
Sorry, I don't have the expertise to do so.
When my design was first conceived, I wasn't concerned about extreme LF performance; my priority was being able to get a realistic sound from the lower strings in orchestral music without inadvertently getting an artificially heavy-sounding bottom end. As you might recall, the upper woofer was originally a TD15M, and I was allowing the TD15H to run upward to overlap the TD15M in an attempt to fill in the baffle step area. It didn't work as well as I had hoped. Results were better using a 416 in place of the TD15M, and using the lower TD15H as a more conventional sub. I think the slightly elevated Q value of the 416 in its 3 cf box fills in the baffle step area more effectively.
Gary Dahl
At yesterday's listening session at Gary's house, there were a couple of recordings that had "substancial" bass. One of those recordings was one that I brought and Gary's speakers were able to deliver the best bass reproduction I've heard so far with that cut. Just Excellent !
Just a note: Thoglette has used the "Shiva" driver as an example in posting #11984. As I was involved in the development of the original Shiva (or "The Official Bass List Subwoofer Driver" as it was originally named) I can assure you that his information involving the Shiva is absolutely correct. I purchased the first production run Shiva ever sold and loaded into a prefabbed cabinet that same day. Great Driver!
Best Regards,
TerryO
Just a note: Thoglette has used the "Shiva" driver as an example in posting #11984. As I was involved in the development of the original Shiva (or "The Official Bass List Subwoofer Driver" as it was originally named) I can assure you that his information involving the Shiva is absolutely correct. I purchased the first production run Shiva ever sold and loaded into a prefabbed cabinet that same day. Great Driver!
Best Regards,
TerryO
I agree with every point in this post. I'll go further: Hoffman's Iron Law, as restated in the original Richard Small papers in the AES Journal, has a more ferocious bite than many appreciate. There is a cube law at work for the F3 frequency: if you want to drop F3 by an octave, the enclosure must be *eight* times larger if efficiency is kept the same, or if size is kept constant, the efficiency must be eight times lower.
So ... if you want response to 20 Hz, it's going to be extremely large, or extremely inefficient, or a combination of both. There is no escape. It is entirely independent of the driver; it describes the complete enclosure system. There is a box efficiency parameter in the equation; vented boxes make more efficient use of the volume/efficiency tradeoff than closed boxes, at the expense of transient response. The difference in the parameter isn't huge, about 2:1, depending on the alignment chosen. In general, more efficient use of volume trades off against transient response.
Aside from theory, passive crossovers are not practical at 100 Hz or below, since the inductors and capacitors get absurdly large and resistive losses start to affect the bass alignment. The combination of Hoffman's Iron Law and the impracticality of passive crossovers leaves only one solution, low-efficiency, heavy-cone subwoofers that are independently powered by multi-hundred-watt amplifiers. But there's no shortage of Class D amplifiers and subwoofer drivers; the home theater and autosound markets have taken care of that.
In the more esoteric world of subjective listening, there is a lessening of the sensation of tonality below 60 Hz. Tone lives in the essential 70 Hz to 7 kHz region, but things are less critical above and below that. Not entirely by accident, the new system has a crossover at 700 Hz, and each driver has a primary operating range covering a little more than a decade (3.3 octaves). A decade of coverage is pretty easy for high-quality direct-radiators and horns, which then sidesteps the need for significant in-band equalization.
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I suspect that you're actually addressing this to Lynn Olson, not Terry Olson. However, since I'm posting and have had some involvement with Subwoofers I will comment on Tapped Horns. I, as well as a buddy are using tapped horns designed around the "Anarchy" 6.5 inch driver designed by my buddy, Kevin Haskins. A Tapped Horn relies on the "tuning" of the enclosure to a degree that is seldom seen other than regular horns. Usually, a tapped horn's tuning is laid out during the design and then carefully "adjusted" afterwards using stuffing within the horn itself.
The "Free Lunch" is paid for with your time spent trying to tune the enclosure/driver combination, which is not necessarily a simple nor easily accomplished task.
Best Regards,
TerryO (the Other Olson
)
Kenderes,
I can add more to TerryO's comments regarding Tapped Horns. I also have a pair of the Tapped Horns using the Anarchy 6.5 drivers. The bass goes down to 25 or 27 Hz, and is fairly smooth up to about 100 Hz. (yes - one 6.5" driver per enclosure)
The TH design can yield a very nice flat SPL response -- which can be fairly low in frequency, and with somewhat high efficiency. The enclosure design and stuffing are a big part of the cost of the lunch for certain.
Also, it may sometimes be necessary to attenuate frequencies above the desired bandwidth. Some electronic filtering or dsp is typically necessary to roll off above the band. I would recommend the following thread, with measurements, data, and discussion.
http://www.diyaudio.com/forums/subwoofers/143714-lab12-tapped-horn.html
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Usually.
However, one of the advantages to the "Anarchy" Tapped Horn is the
fairly small size of the enclosure. Mine measures 30 inches high X 20 inches deep X 8.5 inches wide.
According to Kevin Haskins, who designed the driver, the "Anarchy" driver is capable of producing 114 or 115 dB maximum in the Tapped Horn without problems.
Best Regards,
TerryO
It's the best digital sound I've heard to date. But ... the source material was also the best digital sound I've heard to date, with the highest resolution and the most natural recording techniques.
So it was difficult separating the source from the DAC itself. To the credit of the entire system, you could hear what was on the recordings, which was no small accomplishment.
To exaSound's credit, they are actively supporting the most advanced studio formats, and offering it to the consumer at a very competitive price. Other manufacturers optimize the DAC for DSD or PCM, the DIY Buffalo card makes you buy two different cards (one for each format), and other vendors make you wait for firmware upgrades ... which sometimes never come.
What's surprising about the ESS 9018 is how different the DACs using that chip sound. One DAC, which I briefly auditioned in my own system, was gritty and harsh, and very fatiguing. Another was sweet and almost on the syrupy side, but still just a little short of the Monarchy PCM-1704 DAC I've been using for the last eight years. The rumor mill tells me the OPPO player, with or without mods, sounds different again.
I have not auditioned the e22 or e28 in my own system, but I might in the future. I'm not in a hurry, since I already have two DACs, the Monarchy and the recently arrived Audio-GD SA-2 (also based on the PCM-1704), and I hardly need three DACs to mess with.
My priority list is completing the new speaker in the dual-woofer 416+515 format, and getting a phonograph up and running so I can enjoy my late-Sixties and early-Seventies record collection. The digital sound I'm getting now is pretty decent, and plays CD's, DVD-A's, SACD's, and USB-interface computer formats (Audirvana & Pure Music on a MacBook Pro) just fine.
With the flip of a few switches on the Ariel crossovers, I can switch over to the home-theater side of things with a Marantz 8003 pre-pro & amplifier combo, and Apple and Amazon streaming TV devices. Gary's introduced me to the Digital Concert Hall subscription service from the Berlin Philharmonic, and I am very tempted. It looks and sounds pretty impressive on the Amazon Fire TV streamer; whatever compression algorithms they are using, it's better than other Internet streaming protocols.
I've not heard Gary Dahl's system, but I know it's ahead of mine in terms of speakers, source devices, and the 102" 1080P projector setup. His new speaker is up and running, and he has a first-class phonograph setup with the wonderful Ortofon SPU moving-coil cartridge, one of my favorites. On the digital side of the fence, he can choose between his Monarchy DAC and a custom-built Buffalo DAC, along with a custom music server designed by an ex-Microsoft employee. I can see why he's so pleased with the results.
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Lynn, I have the feeling you might like this approach: http://www.diyaudio.com/forums/vend...crete-r-2r-sign-magnitude-24-bit-384-khz.html
oltos,
After you complete your survey of bass/woofer options, and before you spend any money on Boom-Boom, it would be wise to DEEP DIVE into LeCleach horns and 1.4" compression drivers. This MARRIAGE is the next critical piece of your system after the GPA 416-8B Alnico midbass, and the horn size you select (JMLC 350=23.4" , 400=18.9", 425=16.5") with set the ear level height, and hence allow you to sketch out the correct volume and shape for the midbass cabinet, as well as the bass cabinet.
This thread is based upon the LeCleach profile, but there are many debates on size, build material, rear dampening, adding absorption material inside the horn, crossover slopes and time alignment options, etc.
Your choice of compression driver will determine tone signatures, plus if you need a super tweeter, as well as the optimum Xover frequency and slope.
After you complete your survey of bass/woofer options, and before you spend any money on Boom-Boom, it would be wise to DEEP DIVE into LeCleach horns and 1.4" compression drivers. This MARRIAGE is the next critical piece of your system after the GPA 416-8B Alnico midbass, and the horn size you select (JMLC 350=23.4" , 400=18.9", 425=16.5") with set the ear level height, and hence allow you to sketch out the correct volume and shape for the midbass cabinet, as well as the bass cabinet.
This thread is based upon the LeCleach profile, but there are many debates on size, build material, rear dampening, adding absorption material inside the horn, crossover slopes and time alignment options, etc.
Your choice of compression driver will determine tone signatures, plus if you need a super tweeter, as well as the optimum Xover frequency and slope.
Attachments
Lynn,
Did you by any chance hear the AudioNirvana Neodymium Super 15s that David Dicks of Commonsense audio was showing at RMAF? They ran crossover-less in a simple 5.6 cu ft reflex box and he says that 9 people came to him and volunteered that his was the best sound at the show - at any price!
98dB/W/M w/o crossover has its attractions, but I'm curious to hear your opinion, if you did hear them.
Did you by any chance hear the AudioNirvana Neodymium Super 15s that David Dicks of Commonsense audio was showing at RMAF? They ran crossover-less in a simple 5.6 cu ft reflex box and he says that 9 people came to him and volunteered that his was the best sound at the show - at any price!
98dB/W/M w/o crossover has its attractions, but I'm curious to hear your opinion, if you did hear them.
Um, yes, I did hear the Super15's at the show. To my ears, a very bright and tipped-up sound. If I heard right (and it was very noisy at the time), the AudioNirvana designer doesn't think FR measurements are an important parameter. I left the room after a couple of minutes, while Gary had an extended chat with the designer.
In terms of personal preferences, I'm not the right person to assess a full-range-driver speaker system. My favorite (box-type) speakers have pretty much always been 2-ways with very flat responses, and I've never joined the fullrange whizzer-cone Zu/Fostex/Lowther/Feastrex fan club.
In terms of personal preferences, I'm not the right person to assess a full-range-driver speaker system. My favorite (box-type) speakers have pretty much always been 2-ways with very flat responses, and I've never joined the fullrange whizzer-cone Zu/Fostex/Lowther/Feastrex fan club.
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