Attending the annual Halloween organ bash in Toronto (see posts), I recall getting maybe 95dBc on my old Radio Shack SPL meter. And they are trying real hard to be loud on a big organ. But it is down quite a bit in the low bass. See calibration below.
The "test" for loudness is how easy it is to whisper to your neighbour at a concert. Even at the loudest concerts, that's no problem although not quite applicable to the power present in very low notes like at an organ concert.
B.
Attachments
Steven,
Funny, last night just before falling asleep I remembered Denny Craswell's "A.P.E." show from around 1978 at "Uncle Sams" (later First Avenue) in Minneapolis. Denny opened the show with the theme from "2001, A Space Odyssy" dressed in an ape suit.
Craswell played multiple Mellotrons and Chamberlains, each with different tape loop sounds, while also playing drums made from hollow logs.
His remote keyboard used switches to actuate solenoids that depressed keys on the individual keyboards located offstage, where a technician could attend to them. The "snake" running from the remote had hundreds of lines to allow for playing single or multiple or "split" keyboards- the whole thing was an amazing analog kludge, never seen anything that quite compared to it.
You could record your own loops to play on those instruments, editing and splicing skills were required ;^).
Art
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A few reasons the OP (original poster) may not need massive volume:
He references an organ enthusiast named Owen Jones building a (roughly) 600 litre TL (transmission line) with a cheap 18". The driver is relatively humble, and the design isn't the most efficient use of 600 litres, but it was good enough to keep Owen happy.
As Art said in post 45: it only needs 100 dB to make walls 'flap' at 15-20Hz.
As Ben says in post 61: 95dB at the listening seat may be enough.
The most favored of the options thrown around in this thread (post 6) is the DTS-10 tapped horn. This was a kit that got great output, for a fairly low cost ($975 USD). It seems like a great option for someone who:
a) needs 16-60Hz outdoors (maximum 16-100Hz)
b) has the expertise to build and eq the system
c) can easily move a single, huge object
...but that doesn't really sound like kiaya611, does it? He:
a) needs 16-100Hz (and I bet he wouldn't mind if it was usable to 200Hz).
b) is a novice
c) can't
Hence I'd consider making four sealed boxes loaded with 1 cheap driver per box (rather than one huge box). The driver from VFM audio that Owen Jones used would be OK. Parts Express has a cheap 18" (4 for $480) that looks better.
Dayton Audio DCS450-4 18" Classic Subwoofer 4 Ohm
Note that many other drivers have more displacement, so can give more output for a given box size - but they also cost more, and require more power, which drives costs up further (e.g. what was suggested in post 4 and 5).
The DTS-10 is "over 24 cubic feet", which is big enough to bury a horse. In less archaic terms: about 800 litres.
An equivalent stack of 4 x 200 litre sealed boxes may not match the output of the DTS-10 when used outdoors, but will win in other ways:
- modular (1 or 2 might be enough for small spaces, no need to transport all four)
- nothing to calculate
- easier to build
- more tolerant of driver variation
- easier to transport (especially with stairs and doorways)
- better bandwidth and less eq needed
* that's from a quick hornresp sim. An official clever person might get a different number. Should still be lots.
He references an organ enthusiast named Owen Jones building a (roughly) 600 litre TL (transmission line) with a cheap 18". The driver is relatively humble, and the design isn't the most efficient use of 600 litres, but it was good enough to keep Owen happy.
As Art said in post 45: it only needs 100 dB to make walls 'flap' at 15-20Hz.
As Ben says in post 61: 95dB at the listening seat may be enough.
The most favored of the options thrown around in this thread (post 6) is the DTS-10 tapped horn. This was a kit that got great output, for a fairly low cost ($975 USD). It seems like a great option for someone who:
a) needs 16-60Hz outdoors (maximum 16-100Hz)
b) has the expertise to build and eq the system
c) can easily move a single, huge object
...but that doesn't really sound like kiaya611, does it? He:
a) needs 16-100Hz (and I bet he wouldn't mind if it was usable to 200Hz).
b) is a novice
c) can't
Hence I'd consider making four sealed boxes loaded with 1 cheap driver per box (rather than one huge box). The driver from VFM audio that Owen Jones used would be OK. Parts Express has a cheap 18" (4 for $480) that looks better.
Dayton Audio DCS450-4 18" Classic Subwoofer 4 Ohm
Note that many other drivers have more displacement, so can give more output for a given box size - but they also cost more, and require more power, which drives costs up further (e.g. what was suggested in post 4 and 5).
The DTS-10 is "over 24 cubic feet", which is big enough to bury a horse. In less archaic terms: about 800 litres.
An equivalent stack of 4 x 200 litre sealed boxes may not match the output of the DTS-10 when used outdoors, but will win in other ways:
- modular (1 or 2 might be enough for small spaces, no need to transport all four)
- nothing to calculate
- easier to build
- more tolerant of driver variation
- easier to transport (especially with stairs and doorways)
- better bandwidth and less eq needed
data-bass measurement notes say "The frequency response of the DTS-10 is very rough [...] areas that need aggressively cut with EQ [...] "should be crossed over below 60Hz for best performance."
- more configurable-to optimise output, you could cluster them, firing into a corner (four of the Dayton 18" drivers should give ~120dB @ 16Hz with 500 watts*).
-to optimise smoothness, you could set them up in 4 widely spaced spots
-to optimise smoothness, you could set them up in 4 widely spaced spots
* that's from a quick hornresp sim. An official clever person might get a different number. Should still be lots.
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No chance of 120dB at 16Hz with 4x18" sealed, unless you're going for top-of-the-line drivers.
You can play around here:
Piston Excursion calculator
Edit - the reason I suggested car subwoofers is that they often have more excursion than PA drivers, so you can get similar output from a smaller cone area. A 12" needs 2x the excursion of a 18" to produce the same SPL in a sealed box.
16x 12"s with 10mm one-way travel will produce 114dB at 16Hz. You could get that SPL from 16x 18"s with 5mm Xmax, or 8x 18"s with 10mm Xmax.
It's worth mentioning that, if the piece of music to be played has a lot of sustained low notes, the drivers may well have problems with heating, as well as Xmax.
Chris
You can play around here:
Piston Excursion calculator
Edit - the reason I suggested car subwoofers is that they often have more excursion than PA drivers, so you can get similar output from a smaller cone area. A 12" needs 2x the excursion of a 18" to produce the same SPL in a sealed box.
16x 12"s with 10mm one-way travel will produce 114dB at 16Hz. You could get that SPL from 16x 18"s with 5mm Xmax, or 8x 18"s with 10mm Xmax.
It's worth mentioning that, if the piece of music to be played has a lot of sustained low notes, the drivers may well have problems with heating, as well as Xmax.
Chris
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Yea. That (Piston Excursion calculator) gives 108dB as max.
As also stated on that site, corner loading could give +9dB, getting 117dB as max.
That's not far off my initial number.
Room modes can cause >10dB variation at these frequencies, so the (ideal) calculated numbers are gonna be a rough guess anyway.
As also stated on that site, corner loading could give +9dB, getting 117dB as max.
That's not far off my initial number.
Room modes can cause >10dB variation at these frequencies, so the (ideal) calculated numbers are gonna be a rough guess anyway.
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If you want to use sealed boxes, you need a lot of displacement. Whether it's a single 18" with 42mm of Xmax (110dB at 16Hz) or 8x 12"s with 12mm. Both will cost quite a lot.
Tapped horns are a good way of getting more output for your money, but to get high power at frequencies this low, you need a lot of cabinet.
So,
- DTS10 - big, cheap.
- 1x top-end 18" - smallest cabinet possible, very expensive. Something like this Data-Bass in a sealed box would manage around 109dB at 16Hz on its own. That driver is $2500.
- 8x 12"s - somewhere between the two. I'd suggest something like the JBL GTO1214, which come in around $100 each. Start with four, add another four. I'd build them as columns with wheels at one end so they can go through narrow doors.
A compromise might be a passive radiator solution. A pair of the 18" Dayton home-theatre drivers with a quad of passive radiators might be worth simulating, though could work out as expensive as the driver tested at DataBass.
The DTS10 will likely win out on efficiency over any of these designs, so you could get enough output with a couple of hundred watts per driver. The sealed or passive radiator boxes will need an order of magnitude more power, which could be a problem if we're on a budget.
Chris
Art, I can't believe I didn't put the link to the guy doing tests using a Spectrum Analyzer. It is interesting. I believe he did one experiment with a 64' and 128' stop. Not the joke videos you have probably seen on YouTube, but using actual tone generators and other equipment to produce and "analyze" the "sound" (harmonics in most cases as we cannot hear frequencies that low). Here is the correct link for that: YouTube
I might be disabled, however, I am not dead. I move full upright player pianos weighing 800 - 1000 lbs by myself out of homes and other buildings, down up to 1/2 flights of stairs (a full flight requires 2 to be safe). I have even moved 1 US Ton oscillator cabinets and huge consoles. Having the right equipment and the knowledge of leverage is a very good thing when one has to rely on themselves.
You ARE correct that the DTS10 sounds like the best and least expensive option and yes, it is large and not all that light, but comparatively, it is not what I would deem heavy.
The other options and measurements, thoughts, etc. sound quite correct and thoughtful. I appreciate you taking the time to look into this. Quite honestly, if I had the funds, I would simply make a phone call and have what would do the job either delivered or made. I have never pretended that this was my area of expertise and because IF I end up with a single design that works well universally (to the ears of the majority, as well as mine), I will only need one design and I can replicate it myself. I am quite capable of woodworking/construction, and electrical, (as well as plumbing and most other skills that would be helpful around a farm). If I were younger, I could build a house from the ground up including all of the necessary amenities. I could do it still as I do have the knowledge, but after my stroke, my body isn't quite as willing.
Learning an entirely new and extremely specialized skill such as this, as it would seem to be necessary, to be able to properly evaluate drivers, enclosures and everything else involved is something that people who have a passion for this area would enjoy and totally immerse themselves in. Just as I have with keyboard instruments. I have most of my knowledge in acoustic keyboard instruments, piano, reed and pipe organ and yes, my knowledge has "seeped" into early tube and analog electronic keyboard instruments. I have even gone up to the mid 90s with a couple of my keyboards, but my truest passion is the pipe organ, particularly the large pipe organs that are prevalent on the east coast of the US and those in Europe.
I don't have the money or space to have a large pipe organ, but with the advent and honing of digitally sampled pipe organs, they have reached a level now, that I enjoy them. They are also relatively cheap, as you can build one yourself or the most minimalist to what appears to be a full fledged pipe organ console.
I may never build my dream consoles...and I may...the future hasn't been written yet, but in the mean time, I could have a 5 manual and pedal, 200+ rank digital organ in my home that would be enough to blow me away and since most people don't have a great deal of experience with pipe organs, if it blows me away, I am pretty sure it will be enjoyed by others as well.
In any case, I am a bit off of the actual topic. To be more specific, the weight of a DTS10 is no problem for me, the floor space it uses is actually more of a problem that any other aspect, BUT, I do understand that unless I had a great deal of money, I can't afford the drivers necessary to do the job, but be in small enclosures.
You mentioned Owen, as I did earlier and I have to admit that I am surprised that he was so enthusiastic with his TL speaker. He has more audio equipment than I can imagine and I know he has tried a number of designs to get the low frequencies, including the "House-Wrecker". I even have the plans for that and 4 matched 15" drivers for it. After he built the TL speaker and after hearing him rave about it, knowing he is a "pipe organ person" (theatre mostly vs classical), I though it must have merit if he is impressed by it. He is in Australia though, so there is no chance that I will ever hear his organ in person. I have looked at drivers suggested and carefully looked at the DTS10 design and I know I could build one as a test unit, before I would spend the money to buy a "real" one, just in case it doesn't deliver what I am after. In the big picture, the cost is affordable, but not if it won't do the job. I run physical mock-ups for a lot of things I do before I either build the real thing or buy something, if it is something that I can build. A wood box with baffles (of course places appropriately and of the correct dimensions), would not be difficult for a test.
The calculations that you all do here and the simulations that you run are well above my head and some of the tools, like Hornresp is one of the most specialized programs of all that have been suggested and the hardest to understand (an example).
I don't know if this helps, hurts or doesn't make any difference. I was pretty sure that this thread was over a few posts back, and then I see that there are several new replies. Thoughtful replies. I am wondering about one driver in particular that was suggested as it is like no other driver I have seen and that is the Stereo Integrity BM mkIV 12". Having a flat cone is something I have not seen and don't know how it operates. Is it like the ribbon speakers but for low frequencies? I am curious. The price isn't horrible either...more that I had originally looked at and I like the numbers better than the ones that go with the included driver of the DTS10. I just don't know though. Maybe you all know more about that driver type and how they work to produce the frequencies at the levels that I need (105dBs approx). Thank you, Steven
Steven,
Ribbon speakers use a different design, and have very little excursion.
The Stereo Integrity BM mkIV 12" is a standard moving coil woofer, the flat diaphragm operates the same as a conical cone. The two-piece carbon fiber material it is made from is stiffer than paper or cardboard, my guess is SI purchases it in sheet form and has circles of the cone diameter cut from stock.
The mounting depth is shallow enough to mount in standard stud walls, quite unusual for a driver with 14mm Xmax.
If you want to skip sims and (most) calculations, you can just compare subwoofer drivers the way you'd compare sacks of rice. How much do you get per dollar?
VD (Volume displaced) is just SD (surface area of driver) multiplied by Xmax (amount the cone can move)
Dayton 18"
VD = 935.6 cm³ (1,134.1 cm² * 8.25 mm)
Stereo Integrity BM mkIV 12"
VD = 781.2 cm³ (558 cm² * 14 mm)
$600 gets you 4 Dayton woofers, for 3.7 litre VD (935.6 cm³ * 4)
$600 gets you 2 SI woofers, for 1.5 litre VD (781.2 cm³ * 2)
The Dayton woofer is also about 8dB more sensitive.
mh-audio.nl - Home
...so, to go with Stereo Integrity BM mkIV 12", you'd need to spend several times as much on the drivers to get the same VD, and your amps would cost more - you'd have to use about 10 times as much power to make them play as loud.
The benefit is that the boxes would be smaller.
Several manufactures are offering oddly configured drivers for shallow mounting. They don't offer very good value for money for the application being discussed, and also have pretty high distortion, if these small drivers are indicative:
Test Bench: Tymphany GBS-135F25AL02-04 5.25-Inch Woofer | audioXpress
Test Bench: Dayton Audio LW150-4 6” Ultra-Low-Profile Midwoofer | audioXpress
The JBL GTO1214 that chris661 suggested (post 67) looks like much better option, particularly if you can get some for $100 each (was that a sale price)?
I had a thought, it might work and it might not. Here are two video/audio samples. The first is of the Atlantic City, Midmer-Losh Organ of more than 33,110 pipes in 449 ranks, if fully operational, would be the largest pipe organ in the world and being one of only 2 organs in the world that have full length 64' pipes. This is the lowest 8 notes of the 32' Diapason in the pedal. Listen with the best equipment you have for reproducing low frequencies and listen to it at ~105 dBs-115 dBs.
Then #2 is at the San Filippo Residence/Museum which has the largest theatre pipe organ in the world at ~80 ranks and 8000 pipes. Listen to the Star Wars Symphonic Suite played by Jelani Eddington. Listen to that at approximately at ~114 dBs, again with your best audio equipment and hopefully equipment capable of reproducing the lower frequencies of 32' pipe ranks. This will either work and you will get/feel what I am after, or it won't and a bit of time was wasted. You all have the extreme technical knowledge, I know what a large organ in a large stone space without anyone in the building except for the organist and me...so there was nothing to absorb any of the sound like might happen with a sanctuary full of people. I really hope this works. My best to you, Steven
Then #2 is at the San Filippo Residence/Museum which has the largest theatre pipe organ in the world at ~80 ranks and 8000 pipes. Listen to the Star Wars Symphonic Suite played by Jelani Eddington. Listen to that at approximately at ~114 dBs, again with your best audio equipment and hopefully equipment capable of reproducing the lower frequencies of 32' pipe ranks. This will either work and you will get/feel what I am after, or it won't and a bit of time was wasted. You all have the extreme technical knowledge, I know what a large organ in a large stone space without anyone in the building except for the organist and me...so there was nothing to absorb any of the sound like might happen with a sanctuary full of people. I really hope this works. My best to you, Steven
I feel as though we are reaching a point of mutual understanding...the most difficult part in cross-platform understanding and that helps me greatly as the need here is mine and you all are the experts that I need information from to accomplish my goal.
Simplifying/breaking down the very complex (equations/understanding on the most base level)helps someone like me who is truly in need of this information, but who expertise lies in another specialty. Giving me the "keys" to what I need to look for and explaining them as has been done here:
Until this project, I had never heard of T/S parameters...less the other detailed calculations and simulations that you all do as easily as I, without any information at all could listen to pipes or speakers behind a screen (opaque) and could tell you the rank being played, the general pressure of wind that was being used, aspects of the pipe "cutup", etc. as well as in a huge percentage of the cases whether it was a pipe or driver. My understanding/learning is based on physical attributes in a "real-world" vs simulated (as in running simulations) way. I understand that harmonic structure of different pipe voices, i.e. Diapason, Flute, Reed, etc. whereas you can take physical parameters and calculate them into forms that you can run simulations on. In many ways, a way that would save a tremendous amount of money, instead of literally building different enclosures and trying different drivers in various enclosures to determine if you achieved your goal. Since, in both cases, the room/space itself is actually a very real consideration to the overall success of any given design, the very same pipe or speaker would sound completely different in a space that was carpeted, with drapes and upholstered seating vs the more traditional and established space (as in a pipe organ) of a stone building with little absorbent materials and wooden pews. I like to call the first example, a "living room church"
... but I am extremely traditional and spent my childhood sitting on those hard, uncomfortable pews. I didn't understand until much later the value (musically) in the lack of absorbent materials. The pastors/priests, etc. preferred the "living room church environments as there was no natural reverb and the speech (his/her sermon could be readily heard without any (or much) amplification. The organist or choir director preferred the latter with all of the hard surfaces.Extremely good to know and great illustrations of different drivers using empirical data.
hollowboy, you and some others have been able to bridge the gap in areas of "expertise" to achieve understanding. This helps me and shows even further your understanding of the situation, in that you are able to effective make something very complex much more understandable to someone whose expertise is in another area.
I have regularly dealt with people that asked, what is the difference between a piano and an organ (calling anything with a keyboard [musical], a piano.
I have a questions, as it has been brought up a number of times in this thread. I will preface it by saying that most classical (vs theatre) pipe organ installations put each rank of a division in one spot. That normally represents a keyboard, as classical organs were designed to where each manual (keyboard) and pedals were their own complete organ and could effectively stand alone, giving the organist many of the same voices but at different levels and most often dictating certain ranks that would be found only in those divisions. The larger the organ, the more divisions and the more choices available to an organist. a 2 manual and pedal (2MP) classical organ has a Great division/manual, a Swell division/manual, and a pedal division/pedalboard ("keyboard" played by the feet). The Great was unenclosed, the Swell was enclosed in a "box" with Swell Shades (vertical or horizontal louvers) controlled my expression pedals on the console (like gas pedals), thus allowing a volume control where as the only way you could change volume in the Great is by registration (changing which ranks you chose to give the effect you desired, whether soft, loud or somewhere in between, besides to choose different ranks, i.e. Diapason (the fundamental organ sound, not found on any other instruments), imitative stops like reeds such as a trumpet, clarinet, oboe, etc, Flute stops that are more pure with less harmonics and strings that are more edgy giving the idea of a violin, cello, etc. All of these ranks can be shaped to sound differently with more or less edge, harmonics, etc. and give the organist more voices in variation. The larger the organ, the more ranks and thus the more choices available. In very large organs, you can have a 5MP console with each keyboard, again being it's own division, Choir, Great, Swell, Solo, Bombarde as an example as the builder along with the organist decide on what ranks and divisions to choose based on the organ's repertoire is going to be played. The first 2 are almost always the same, although with different names depending on where (geographically) the organ is built (the US, the UK, France, Germany, etc. After the Great and Swell, in most case, at least in the US, the 3rd manual is the Choir, so the Great is the loudest, the Swell is quieter and controlled by the Swell shades and the choir being quieter yet and also being enclosed. After that, it depends on where the organ is, what the builder and organist have decided, etc. In huge organs, you could have a division that is only Strings as in the Wannamaker organ in Philadelphia, having over 100 ranks * 61, 73 or 85...even 97 pipes each, although usually in an organ that large, they rarely go above 73 notes/pipes in each ranks because you would only need to add another rank to get a higher (or lower) register. That is uncommon. Usually each division has a couple of ranks of strings,m just as they would have a couple ranks of flutes, reeds, etc. to give variation to the sounds available in a given division. In the cases where the organ is huge, you would have more that 5 divisions and only in a couple of cases more than 5 manuals. In cases like that, you have controls that will allow you to couple a division to a given manual and also the ability to turn off the native division played on that division, as is the case in the Wannamaker organ, the Atlantic City Boardwalk Hall organ (that has 7 manuals), the FCCLA (First Congregational Church of Los Angeles, to name a few) that have as many as ~18 divisions, but fewer manuals.
Sorry...I went off on a tangent a bit explaining the basics of organ construction/design. Being my forte (and my passion), it is easy for me to get side-tracked like that.
Back to the topic at hand. I was asking if it would be better to have a number of smaller enclosures/subwoofers placed at different locations in a space rather than one large one? Being that, as a rule, the pedal division is in one place and in some cases (other that in huge organs) split into two places (i.e. right and left side of a space). The ranks are not broken, but the voices/ranks are divided intact into 2 different locations, usually having to do with space availability.
Because I am trying to replicate a pipe organ only, I just wonder if you would follow pipe organ construction, i.e. having one source or because of the way drivers work, or space coverage, etc. you would divide the sound up to get the immersive experience that is natural in a reverberabant space. Being that I am not trying to re-create a movie/home theatre, my goals are similar in some ways, but different as I do not want it to sound "fake", i.e. if someone intimately familiar with pipe organs were to be listening, would they feel it is an accurate/acceptable representation of an acoustic pipe organ.
Thank you for tolerating my monologue. Please know, I am just trying to bring understanding from my side so that you can understand as best as possible, the goal.
Just in case you might find this interesting, I ran across a gentleman in the UK that has (and is) doing experimentations with loud speakers as they pertain to the reproduction to pipe organs. He also illustrated a 64' and 128' pipe using sound generators to show that even though not musical alone, can add to an ensemble. Here are the links:
The 64ft and 128ft pedal organ stop experiment
Effect of speakers on electronic organ and Hauptwerk realism
I hope you find them interesting.
Best wishes,
Steven
I'd like to remind those posting here of the certain long rambling threads in recent times that proved to be near-total wastes of time and bile, at least from the POV of DIYaudio members. First to mind was the other organ thread. Then the gigantic outdoor horn.
What are the characteristics of such threads (and this thread) that proved their undoing?
B.
What are the characteristics of such threads (and this thread) that proved their undoing?
B.
I'm not sure if they're even making that unit any more, though I do remember them being around that price new online.
I'm sure some shopping around would find similar drivers available. I happen to have a pair of GTO1214s that I have a love-hate relationship with. They move a lot of air for a 12", but they're not the cleanest-sounding drivers in the world.
Chris
Ben, I completely understand your point, however, how do you reach a mutual understanding to communicate each side of effectively 2 languages?
I do not understand the question...would you care to expound on the question?
All I want is effectively an economical driver and enclosure plans that will satisfy my needs in the application, nothing more. I cannot however purchase and try 10 different drivers and build as many enclosures to see what (if any) will work.
Sorry for the "...that proved to be near-total wastes of time and bile."
How would you recommend that I achieve my goal without explaining those parts that I understand and others may not?
The JBL Club 1224 might be the closest match to that driver. The GTO series (and corresponding Infinity Reference series from the time) had fairly decent specs for the price. Perhaps the time those drivers came out was the best time get car audio drivers with a good price/performance ratio. The ones that are available on the market now from JBL/Infinity? The specs are not really impressing me that much.
Link: JBL Club 1224 (club1224) 1100W Max (275W RMS) 12" Club Series
Ok, getting back to what was originally asked (I'm not going through the long diatribes that followed).
My opinions: To reproduce 16 Hz efficiently, start with a driver that has an Fs around or just above that, and a low Qts and good Xmax, as likely the best way to get there would be some sort of vented alignment with an Fb of 16 Hz and EQ from 16 Hz up. Like an EBS alignment.
I had a look at what Dayton has on offer, and couldn't come across a driver with that Fs. However this one comes close: Dayton Audio RSS460HO-4 18" Reference HO Subwoofer 4 ohm
Have a look at what that looks like in a large box vented to 16 Hz (or an offset TL that resonates at that frequency). If it has a smooth, downward-sloping passband, that can be fixed with a little EQ. Build one, measure, then build multiples if you need more output (every additional one driven by the same amount of power will add 6dB to peak SPL capability when they're stacked together)
Here's an idea to start off with - a ~260 L offset-driver stuffed TL that meets the bandwidth that you're looking to achieve (with a bit of EQ), using the driver I mentioned above. A 1kW amp should be enough for it. The design needs some refinement (for example, it might not need all of that stuffing, and I'd probably adjust it to have a proper flared vent) and of course it has to be folded into a box, but then I've got design spreadsheets to assist with that.
My opinions: To reproduce 16 Hz efficiently, start with a driver that has an Fs around or just above that, and a low Qts and good Xmax, as likely the best way to get there would be some sort of vented alignment with an Fb of 16 Hz and EQ from 16 Hz up. Like an EBS alignment.
I had a look at what Dayton has on offer, and couldn't come across a driver with that Fs. However this one comes close: Dayton Audio RSS460HO-4 18" Reference HO Subwoofer 4 ohm
Have a look at what that looks like in a large box vented to 16 Hz (or an offset TL that resonates at that frequency). If it has a smooth, downward-sloping passband, that can be fixed with a little EQ. Build one, measure, then build multiples if you need more output (every additional one driven by the same amount of power will add 6dB to peak SPL capability when they're stacked together)
Here's an idea to start off with - a ~260 L offset-driver stuffed TL that meets the bandwidth that you're looking to achieve (with a bit of EQ), using the driver I mentioned above. A 1kW amp should be enough for it. The design needs some refinement (for example, it might not need all of that stuffing, and I'd probably adjust it to have a proper flared vent) and of course it has to be folded into a box, but then I've got design spreadsheets to assist with that
.Attachments
...but then I've got design spreadsheets to assist with that
Everything you have said sounds good and I am glad to "cut to the chase".
With that in mind, what "Design Spreadsheets" do you have and are they available or what do they cost?
Thank you,
Steven
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