Thanks Scott,I understand that I should select 18' Pro driver rather on dual 12' drivers to go flat 20Hz -if so,would you be kind enough to recommend me,in your opinion, the best possible 18' driver to go down to 20Hz up to 300-500Hz without choking or distortion with excellent Fs and Xmas with relatively "smallish" sealed enclosure ?
Your set seems amazing-is it an infinite baffle on the upper left side,what drivers&horns do you use ?
Your set seems amazing-is it an infinite baffle on the upper left side,what drivers&horns do you use ?
Where in the world are you located?
There can be quite large variations in price on various brands pending on your geographic location. If you want some suggestions on 18" pro drivers, give a mention of which site, store or country you would like to order from.
There are many suitable 18" available, no need to pay extra for the same performance.
There can be quite large variations in price on various brands pending on your geographic location. If you want some suggestions on 18" pro drivers, give a mention of which site, store or country you would like to order from.
There are many suitable 18" available, no need to pay extra for the same performance.
FYI
Here is a site that deals in the basics of horn design.
For a 20 Hz horn, you need an 8 Meter length and a mouth diameter of 8.5 meters per this site.
Folded horn speaker design - explanation and calculator
I have heard of people using a shipping container as a basis for a 20 Hz horn.
Good luck with your project.
Here is a site that deals in the basics of horn design.
For a 20 Hz horn, you need an 8 Meter length and a mouth diameter of 8.5 meters per this site.
Folded horn speaker design - explanation and calculator
I have heard of people using a shipping container as a basis for a 20 Hz horn.
Good luck with your project.
Thanks for the info. and advice.I'll forgo sub horn and settle for ordinary subwoofer and use horns for the rest.I tend to select Mach 5 -it seems one of the best 18' or even 21' drivers that can go down to 20Hz with great Fs and Xmax-are you aware of any better 18' or 21' drivers with better data and sound performance ?!
My only problem is that I don't know what is the minimum size of sealed enclosure I should build for it ?
My only problem is that I don't know what is the minimum size of sealed enclosure I should build for it ?
Have you researched maintaining stereo woofers in your room, like a front/back quartal configuration, versus summed mono woofers?
1) Stereo bass down to 20Hz has been produced in low distortion, high SPL since 1982 on CDs, DVD-As, SACDs, and 5.1 movies.
2) Most people with normal hearing can identify the difference between stereo vs. mono bass. Stereo bass has phase for location.
3) At frequencies below 80Hz most people with normal hearing cannot isolate the physical location of the woofer. (80Hz is THX standard)
----Expert listeners can isolate location of woofers down to 60Hz by focusing on impact harmonics, port noise, upper harmonic distortion.
4) Not being able to locate the subwoofer is a good cost simplification, but summing low bass into mono degrades true stereo recordings.
5) With stereo subwoofers, any out-of-phase bass information in a true stereo (acoustic) recording is reproduced properly at full level, adding immensely to the perceived width and depth of the room in which the recording was made.
6) Irregular room shapes can have an effect on even the subwoofer frequency stereo soundstage.
7) Geddes: "The mains should be designed for the best possible direct field with as flat a power response as possible." Using the mains for Room Equalization can only make the soundstage worse.
Low-Frequency Optimization Using Multiple Subwoofers
TODD WELTI AND ALLAN DEVANTIER
INNOVATION | Harman
Attachments
flat to 20Hz at 104dB continuous AES (110dB peaks)
The Precision Devices 1851 driver (sim attached) is perfectly suited to your requirements.
A single driver in a small (60 litres) sealed box will give you ultra low distortion bass down to 20Hz @ 104dB continuous (110dB peaks) with the lowest power compression of any 18 inch driver I have heard..... Just 1.6dB compression at 1,000 watts AES (not audiophile RMS / music programme etc)... This is a seriously well engineered Pro driver.
5 inch voice coil, good ratio of Mms / High Bl (for a an 18 inch driver) and easily copes with the texture and detail of low mid-range.
I have used it up to 400Hz, but prefer it covering the 20Hz to 250Hz band.
You will gain an extra 6dB over and above the attached sim if you place the sub(s) in a corner.
If you need higher SPL use a pair you will gain an extra 3dB SPL, use 4 subs and gain 6dB.
These are really small 60 litre, easy to build sealed box designs.
The two key requirements are:
Lots of clean amplifier power.
Good DSP to Eq the response, allowing for room gain they typically need 15dB to 18dB of eq boost around 30Hz.
4 subs in corner locations will give you 116dB continuous SPL with 122dB peaks at 20 Hz.... Be careful... Thats hearing damage levels!
Cheers
Derek.
PS The attached sim was for another guy who was using them over the 50Hz to 500Hz band and comparing them to a Beyma 18 inch driver.
The Precision Devices 1851 driver (sim attached) is perfectly suited to your requirements.
A single driver in a small (60 litres) sealed box will give you ultra low distortion bass down to 20Hz @ 104dB continuous (110dB peaks) with the lowest power compression of any 18 inch driver I have heard..... Just 1.6dB compression at 1,000 watts AES (not audiophile RMS / music programme etc)... This is a seriously well engineered Pro driver.
5 inch voice coil, good ratio of Mms / High Bl (for a an 18 inch driver) and easily copes with the texture and detail of low mid-range.
I have used it up to 400Hz, but prefer it covering the 20Hz to 250Hz band.
You will gain an extra 6dB over and above the attached sim if you place the sub(s) in a corner.
If you need higher SPL use a pair you will gain an extra 3dB SPL, use 4 subs and gain 6dB.
These are really small 60 litre, easy to build sealed box designs.
The two key requirements are:
Lots of clean amplifier power.
Good DSP to Eq the response, allowing for room gain they typically need 15dB to 18dB of eq boost around 30Hz.
4 subs in corner locations will give you 116dB continuous SPL with 122dB peaks at 20 Hz.... Be careful... Thats hearing damage levels!
Cheers
Derek.
PS The attached sim was for another guy who was using them over the 50Hz to 500Hz band and comparing them to a Beyma 18 inch driver.
Dear Derek,thanks for the info. and forgive me for further bothering you since I looked at Precision devices site and found out that the model called 1851-2 has Frequency range of 35Hz-2kHz,Fs-37Hz and Xmax-12m"m and even checked all models of PD and couldn't even a driver unit which goes down to 20Hz so it seems that I missed something serious here and my utmost apologies in advance .Hence',I'd appreciate your detailed explanation .
lower cost alternative
If seeking high efficiency, along with a reasonably low F3, according to Hoffman's Iron Law, it's going to take a very large enclosure.
Due to this driver's larger than average Qts value, the vented box alignment is a chevychev, with minimal ripple. Of special note here, is the much lower than average moving mass value for a cone of this size. It would require a box size of 14 cubic feet, tuned to 30Hz, to yield 30Hz F^3, with a real true 95.9 db sensitivity.
https://www.parts-express.com/pedocs/specs/290-696--eminence-impero-18a-specifications.pdf
If seeking high efficiency, along with a reasonably low F3, according to Hoffman's Iron Law, it's going to take a very large enclosure.
Due to this driver's larger than average Qts value, the vented box alignment is a chevychev, with minimal ripple. Of special note here, is the much lower than average moving mass value for a cone of this size. It would require a box size of 14 cubic feet, tuned to 30Hz, to yield 30Hz F^3, with a real true 95.9 db sensitivity.
https://www.parts-express.com/pedocs/specs/290-696--eminence-impero-18a-specifications.pdf
When I built a dedicated subwoofer years ago, the single overall best driver I found (57mm Xmax peak-to-peak excursion / 21 inch cone area / 6 inch voice coil, high power / sensitivity, managable weight 22kg drive unit for portable PA use, etc.) was Precision Devices PD2151 Neodymium 21 inch, so I bought two of them, and built myself a pair of subs. My cabinets are only 45kg each on castors, and fit through a single domestic doorway, and both can fit into estate car boot with seats folded down, etc. That was 20 years ago. To this day I've never seen anything better (without being much heavier / bigger) or ever felt I needed any upgrade. Each has no problem getting to 20Hz or 15Hz or 10Hz... depends on system's active EQ curves.
Precision Devices have discontinued that specific model now, but still have similar 21 inch and 24 inch models today, and spoilt for choice with 18 inch drivers.
When I built a high-output portable 3-way with 15 inch woofer, the best overall bass driver I found was Faital Pro 15XL1400.
I made huge database of all suitable 12 inch and 15 inch woofers Thiele / Small parameters, to run their specs through a computer simulation inside a fixed hypothetical 100 litre cabinet volume vented at 20Hz, and compared all their graphs, and the Faital Pro 15XL1400 was the winner for most low frequency output in that restricted cabinet volume. Close 2nd place was BMS 15N850V2.
With FIR correction it's flat to 14Hz in my current 3-way cabinet with 18 Sound 8NMA610 midrange and Beyma TPL150H tweeter, and each cab weighs only 37kg.
I haven't thoroughly researched 18 inch size for myself, because I've never needed one - 18 inch is too big (slow transients) for a 3-way bass and too small for a proper subwoofer IMHO - although maybe ideal bass in a 4-way design - so I'd recommend a good place to start researching would be the equivalent 18 inch versions of those models...
FaitalPRO | LF Loudspeakers
Faital Pro 18XL2000 (18 inch)
Faital Pro 18XL1800 (18 inch)
Precision Devices™ Product Range
Precision Devices PD.185N02
Precision Devices PDN.1852
BMS Neodymium Cone Drivers
BMS 18N862
BMS 18N850V2
Also 18 Sound and Beyma and JBL make some very nice pro woofers too.
Like other people have said, you need cone area(!) and large linear Xmax(!) combined with massive voice coil power handling.
Manufacturer's sensitivity spec "99dBSPL/watt" or whatever is usually measured at the highest peak on their graph, or at 1kHz so doesn't tell you much about how it will perform in low bass range. So don't be fooled comparing sens specs between subwoofers.
Also don't buy car audio boombox / SPL competition subwoofers if you're planning to use for seriuous hifi music listening- because they typically have very high moving mass so will just go boooooooooom.
Unless you're building a HUGE cabinet, most of these 18 inch woofers will show similar roll-off in a given cabinet size / vent freq, so you need a cabinet simulator program to get viewing graphs to see best performer before you buy, or build a test cabinet and buy the best half a dozen drivers to try and test / send back what you don't keep, but you'll struggle to get honest accurate measurments in a domestic room at low bass freqs.
If you really care about 20Hz, also consider a 21 inch woofer not an 18 inch.
Precision Devices have discontinued that specific model now, but still have similar 21 inch and 24 inch models today, and spoilt for choice with 18 inch drivers.
When I built a high-output portable 3-way with 15 inch woofer, the best overall bass driver I found was Faital Pro 15XL1400.
I made huge database of all suitable 12 inch and 15 inch woofers Thiele / Small parameters, to run their specs through a computer simulation inside a fixed hypothetical 100 litre cabinet volume vented at 20Hz, and compared all their graphs, and the Faital Pro 15XL1400 was the winner for most low frequency output in that restricted cabinet volume. Close 2nd place was BMS 15N850V2.
With FIR correction it's flat to 14Hz in my current 3-way cabinet with 18 Sound 8NMA610 midrange and Beyma TPL150H tweeter, and each cab weighs only 37kg.
I haven't thoroughly researched 18 inch size for myself, because I've never needed one - 18 inch is too big (slow transients) for a 3-way bass and too small for a proper subwoofer IMHO - although maybe ideal bass in a 4-way design - so I'd recommend a good place to start researching would be the equivalent 18 inch versions of those models...
FaitalPRO | LF Loudspeakers
Faital Pro 18XL2000 (18 inch)
Faital Pro 18XL1800 (18 inch)
Precision Devices™ Product Range
Precision Devices PD.185N02
Precision Devices PDN.1852
BMS Neodymium Cone Drivers
BMS 18N862
BMS 18N850V2
Also 18 Sound and Beyma and JBL make some very nice pro woofers too.
Like other people have said, you need cone area(!) and large linear Xmax(!) combined with massive voice coil power handling.
Manufacturer's sensitivity spec "99dBSPL/watt" or whatever is usually measured at the highest peak on their graph, or at 1kHz so doesn't tell you much about how it will perform in low bass range. So don't be fooled comparing sens specs between subwoofers.
Also don't buy car audio boombox / SPL competition subwoofers if you're planning to use for seriuous hifi music listening- because they typically have very high moving mass so will just go boooooooooom.
Unless you're building a HUGE cabinet, most of these 18 inch woofers will show similar roll-off in a given cabinet size / vent freq, so you need a cabinet simulator program to get viewing graphs to see best performer before you buy, or build a test cabinet and buy the best half a dozen drivers to try and test / send back what you don't keep, but you'll struggle to get honest accurate measurments in a domestic room at low bass freqs.
If you really care about 20Hz, also consider a 21 inch woofer not an 18 inch.
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Small sealed box design advantages
Happy to explain some more details.
Rod Elliot is a top guy with over 20 years experience in both high end audio and PA sound rigs, this link http://sound.whsites.net/project48.htm explains the ELF subwoofer principal.
In summary one selects a driver / sealed box combination with a high box resonance and then drive the sub below below the resonant frequency.
The advantages of ELF Vs conventional sealed or ported / TL etc are:
Performance - Critically damped, accurate time domain. This gives drum and percussion transients a life like slam and at the same time a rich textured sound to low end piano / Cello etc.
Cost and size - Its cheaper and easier to build a small rigid sealed box Vs the usual ported refrigerator!
Flexibility - As DSP is a requirement of the ELF principal (Mini DSP, DBX PA 2, or an AV amp etc) one can ensure the system is matched to almost any room size, shape furnishings.
The PD 18 inch I use is really superb, but also (at less than half the price) the Beyma SM115 K is a great buy.... I also have a pair of them in 50 litre sealed box's with less than 250 watts driving them.... Really really great sound.
Dynaudio 4 way - About 10 years ago I found this : http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Serious Sub.pdf
Tony is very good and uses 21 inch PD drivers with 6 inch voice coils....Is this what you use?
Very good low end extension but not good above 100Hz.... The PD 18 inch or Beyma 15 inch sound way better on music if using them above 100Hz.
Hope this helps and hope you enjoy the articles.
Cheers
D.
Happy to explain some more details.
Rod Elliot is a top guy with over 20 years experience in both high end audio and PA sound rigs, this link http://sound.whsites.net/project48.htm explains the ELF subwoofer principal.
In summary one selects a driver / sealed box combination with a high box resonance and then drive the sub below below the resonant frequency.
The advantages of ELF Vs conventional sealed or ported / TL etc are:
Performance - Critically damped, accurate time domain. This gives drum and percussion transients a life like slam and at the same time a rich textured sound to low end piano / Cello etc.
Cost and size - Its cheaper and easier to build a small rigid sealed box Vs the usual ported refrigerator!
Flexibility - As DSP is a requirement of the ELF principal (Mini DSP, DBX PA 2, or an AV amp etc) one can ensure the system is matched to almost any room size, shape furnishings.
The PD 18 inch I use is really superb, but also (at less than half the price) the Beyma SM115 K is a great buy.... I also have a pair of them in 50 litre sealed box's with less than 250 watts driving them.... Really really great sound.
Dynaudio 4 way - About 10 years ago I found this : http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Serious Sub.pdf
Tony is very good and uses 21 inch PD drivers with 6 inch voice coils....Is this what you use?
Very good low end extension but not good above 100Hz.... The PD 18 inch or Beyma 15 inch sound way better on music if using them above 100Hz.
Hope this helps and hope you enjoy the articles.
Cheers
D.
In my experience, Fs is quite an irrelevant parameter. For example, this driver has no problem playing down to 16 Hz at 110+ dB SPL levels in a domestic setting, yet has Fs of 40 Hz. That's more than a whole octave below Fs! For ULF, it pretty much comes down to volume displacement Vd.
If you simulate a "supersub" like Dayton Ultimax and a high Xmax PA sub, like a B&C, you'll find that their sensitivities around 20 Hz tend to be similar, around 86...88 dB/W, but the low Mms, low inductance, high BL PA driver has way more sensitivity in midbass. That gives the illusion of not being able to go low, but in fact exactly the opposite is true - the "supersub" is not able to go high. Many "supersubs" really struggle above 50 Hz, as seen on Databass website.
Attached is the FR of the cheap 18" driver linked above, in-room and properly EQ-d
Attachments
Hi Ernie M,
Wow, that Ayra Airblade looks impressive. Haven't seen it before. It's around £1000 cost but very new. Not much technical spec about it on their website...
Do you already have one yourself for your build then?
Is it more of a domestic hifi driver, or suitable for pro audio P.A. levels? Hard to know without a datasheet.
Hi Overkill Audio,
The Precision Devices 21" mentioned in your weblink story is the PD.2150 which has ceramic magnet. It may be the latest one on PD's website, where they've updates the specs a bit.
I have an old Feb 1996 datasheet for their original PD-2150 which was 750W rms / 1500W program, net weight 31.75kg.
The version I own (purchased about 20 years ago) was the slightly later PD2151 with Neodymium magnet, which is 900W rms / 1800W program, net weight 22kg, which is long discontinued now.
They're both physically quite similar and the cones look identical, but the more efficient Neo magnet gives a significant 30% weight reduction, as well as (from what I can see) decreasing the overall bulk of the rear magnet housing, giving you a bit more free internal air volume in your cabinet enclosure, although they're both listed as approx 22 litres. Looking at my Feb 1996 datasheets for both models, the Neo PD-2151 also has bigger magnetic gap depth (15mm vs 11.5mm), bigger voice coil winding depth (36mm vs 30mm) and bigger displacement limit (57mm vs 38mm) which allows it more cone excursion / higher power handling (900Wrms vs 750Wrms.) Though it does have slightly higher Fs of 26Hz vs 22Hz, and slightly different Qes, Qms, Qts and Vas parameters, etc. but most of the physical dimensions including the cone area, mounting holes, 152mm / 6 inch voice coil are all identical.
I'm not using it above 100Hz - just as a true subwoofer, so it picks up wherever the top speakers roll off, which was around 40Hz in the case of my old 12 inch P.A. tops, or 55Hz for my Yamaha DSR112 tops, but with my newer main 15 inch 3-way cabs, or my old 4-way Dynaudios I don't strictly need the subwoofer, as I've got flat response to below 20Hz already.
The sheer scale of the 21's deep bass is more the "helicopter landing outside in your garden" type feeling! Nothing can beat 'em for that though.
Wow, that Ayra Airblade looks impressive. Haven't seen it before. It's around £1000 cost but very new. Not much technical spec about it on their website...
Do you already have one yourself for your build then?
Is it more of a domestic hifi driver, or suitable for pro audio P.A. levels? Hard to know without a datasheet.
Hi Overkill Audio,
The Precision Devices 21" mentioned in your weblink story is the PD.2150 which has ceramic magnet. It may be the latest one on PD's website, where they've updates the specs a bit.
I have an old Feb 1996 datasheet for their original PD-2150 which was 750W rms / 1500W program, net weight 31.75kg.
The version I own (purchased about 20 years ago) was the slightly later PD2151 with Neodymium magnet, which is 900W rms / 1800W program, net weight 22kg, which is long discontinued now.
They're both physically quite similar and the cones look identical, but the more efficient Neo magnet gives a significant 30% weight reduction, as well as (from what I can see) decreasing the overall bulk of the rear magnet housing, giving you a bit more free internal air volume in your cabinet enclosure, although they're both listed as approx 22 litres. Looking at my Feb 1996 datasheets for both models, the Neo PD-2151 also has bigger magnetic gap depth (15mm vs 11.5mm), bigger voice coil winding depth (36mm vs 30mm) and bigger displacement limit (57mm vs 38mm) which allows it more cone excursion / higher power handling (900Wrms vs 750Wrms.) Though it does have slightly higher Fs of 26Hz vs 22Hz, and slightly different Qes, Qms, Qts and Vas parameters, etc. but most of the physical dimensions including the cone area, mounting holes, 152mm / 6 inch voice coil are all identical.
I'm not using it above 100Hz - just as a true subwoofer, so it picks up wherever the top speakers roll off, which was around 40Hz in the case of my old 12 inch P.A. tops, or 55Hz for my Yamaha DSR112 tops, but with my newer main 15 inch 3-way cabs, or my old 4-way Dynaudios I don't strictly need the subwoofer, as I've got flat response to below 20Hz already.
The sheer scale of the 21's deep bass is more the "helicopter landing outside in your garden" type feeling! Nothing can beat 'em for that though.
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