Has anybody built a FSP 18 SXY?

Ive been looking for the best possible subs i can build for my dub, tekno and psytrance system.
I love folded horns/ front loaded horns because of there size, shape and output.
But i don't know what the best option is.
I will use 2x 1850 horns as kicks.

The Fsp-18-sxy peaked my interest, it looks very nice and the response and plans look good to.
But i dont think anybody has actually built them, at least i can't find any.
The buildplan is easily findable on the interenet and you can also see it here :
https://planssystemes.notion.site/F...e606ccad58?v=a0a05a48606240f3b820a0984fabfc39

Does anybody have more info on this horn? should i build it? Should i first test a single one? Should i design my own flh?
Any other recommendations?

Thanks in advance!
Cesar Baets
 
i have not seen that model before and did not know anybody who actually build them and tested
the main page is kind of misleading
as it says a response of 56Hz on the low end but the HR graph shows more that it is tuned at 35Hz
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the HR file is published but somebody who have more experience in HR can verify that the plans match the .TXT file for HR

dubstep needs something along the 30Hz flat line type of sub
so i recommend that you look for some designs that can hit 30Hz flat

speaking of that, the lower you go, the bigger the cab

what is your target SPL ?
you can hit your target SPL with less count of high power drivers loaded cabinets
or lower power drivers with more cabinets

it is a juggling game
whatever path you choose you need to have the proper amplification and DSP to protect your investment

here are a couple of designs that were built and tested
Flat to 30Hz TH

SKRAM 21" BandPass Sub
 
i have not seen that model before and did not know anybody who actually build them and tested
the main page is kind of misleading
as it says a response of 56Hz on the low end but the HR graph shows more that it is tuned at 35Hz
View attachment 1302037

the HR file is published but somebody who have more experience in HR can verify that the plans match the .TXT file for HR

dubstep needs something along the 30Hz flat line type of sub
so i recommend that you look for some designs that can hit 30Hz flat

speaking of that, the lower you go, the bigger the cab

what is your target SPL ?
you can hit your target SPL with less count of high power drivers loaded cabinets
or lower power drivers with more cabinets

it is a juggling game
whatever path you choose you need to have the proper amplification and DSP to protect your investment

here are a couple of designs that were built and tested
Flat to 30Hz TH

SKRAM 21" BandPass
Do you DB with spl? or what do you mean with spl?

Do you think its a good cabinet or do you think there are better folded horns i can build?

For Dsp im going te buy a DBX driverrack pa2 and for amp one from cvr
I currently have 6 broken ciare ndh 18-4s drivers, which are similar in thieleparameters to a pd1850 if im not wrong.

Its indeed a huge cabinet, i want to build a big wall so i like the height and width, but the depth isn't my interest so less deep with the same output would be nice.

Ive read quite a lot about xmax and such, and you also wrote about it, is this about the fartest point the dustcap will travel from the magnet? and so will it hit the mouth of the horn/driverplate?

Thanks for the simulations, im trying to learn hornresp but i haven't put enough time into it to fully work with it.
 
The SPL means Sound pressure level, in general it's one of the main targets for a Sound Project.

Nowadays with driver capable to handle much more power compared to the past may result in drivers heating faster, so considering a sealed chamber design for a PA doesn't align with current practices. You may loose a lot of SPL due to compression and also overheating may damage your driver and that isn't hard with the music styles you planning to use. If it the sealed chamber with FLH really has the sound you like more, you may should think about ways to improve heat transfer in order to better cooling the driver. One way can be troughs add vents in the chamber or metallic plates.

The SuperBassHorn is an alternative to FsP 18 SXY.

It might be better to go for higher order designs that are well established and you can tune then to your needs, they will delivery more SPL/Box improved cooling but reduced frequency bandwidth. Check the family below:

Tapped Horns
6th Order parallel (Manifold/Devastator/others)
Paraflex

From the link below you can find CAD files for free integrated with hornresp so you can do fast simulations with any design.

https://freeloudspeakerplan.rf.gd
 
Lord,
If he don't have a clue what SPL is...
Less a link to you sim templates for free cad

What he needs is a turnkey plan
Devastator is a good one
Paraflex type O single or dual 18

Ricci skram hits low also 30hz and you can plug the ports to hit lower.

The FT30 thread also flat to 30 TH
Other than that it depends on the skills he have for wood working or hire someone to cnc the wood for him.
 
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I know that spl stands for sound pressure level, but when looking at the horn resp graph, it seems to be a synonym for decibels, and I've never understood the difference.

Im not a fond of paraflex designs to be honest. Neither of all the compound and tapped designs. Just looks wise its really lacking. Speakers are not about look but about output so thats why i love folded horns because they have both. Im planning on varnishing my horn instead of using warnex so i still have the warm wood which makes the venues cozy.

The output of those other designs might be better but it doesn't fit the image.

Woodworking skill is not an issue.

I mostly have to know if i need to modify the fsp-18-sxy plans with ventilation, and extend the driver plate thickness to ensure the dustcap doesn't hit the throat of the horn.
When talking about xmax, it means the fartest point the dustcap will reach away from the magnet right?

If there are better free horn plans like for example the wsx, labhorn or sbh, please let me know.
 
I know that spl stands for sound pressure level, but when looking at the horn resp graph, it seems to be a synonym for decibels, and I've never understood the difference.

Im not a fond of paraflex designs to be honest. Neither of all the compound and tapped designs. Just looks wise its really lacking. Speakers are not about look but about output so thats why i love folded horns because they have both. Im planning on varnishing my horn instead of using warnex so i still have the warm wood which makes the venues cozy.

The output of those other designs might be better but it doesn't fit the image.

Woodworking skill is not an issue.

I mostly have to know if i need to modify the fsp-18-sxy plans with ventilation, and extend the driver plate thickness to ensure the dustcap doesn't hit the throat of the horn.
When talking about xmax, it means the fartest point the dustcap will reach away from the magnet right?

If there are better free horn plans like for example the wsx, labhorn or sbh, please let me know.
Ok, let's move on
For existing plans that are popular now days you will need to get the right driver , so let us know if you are willing to buy new drivers.

Or to be more specific what is your budget?
That will help us to point you in the right direction.

Without that basic Info we can't be specific as there are dozens of plans.

But we know already that size is not issue for you.
 
About xmax

Speaker Xmax is a critical specification used to describe the maximum linear excursion of a loudspeaker’s diaphragm or cone. In simpler terms, it refers to how far the speaker’s cone can move back and forth without causing damage to the speaker itself1. Let’s dive into more details:

  1. What Is Speaker Xmax?
    • Speaker Xmax is often included as part of the specifications of a speaker driver. It represents how far the voice coil (a copper wire wound around a former) can move within the speaker’s magnetic gap.
    • Beyond the Xmax distance, distortion and undesirable outputs start affecting speaker performance.
    • There are two types of voice coil designs: overhung and underhung.
      • In an overhung design, some of the voice coil extends beyond the magnetic gap, and Xmax is calculated as the amount of voice coil that extends beyond the gap.
      • In an underhung design, there is a distance between the top of the voice coil windings and the top of the magnetic gap, and this distance is the Xmax.
    • Xmax is also called “maximum linear excursion” within the speaker industry2.
  2. Is Xmax the Same as Speaker Excursion?
    • No, Xmax and excursion are not the same.
    • Xmax refers to how far the voice coil can move out of the speaker gap before distortion occurs.
    • Speaker excursion, on the other hand, refers to how far the entire cone assembly can move during operation, which could be beyond Xmax until mechanical stops are hit.
  3. How Is Xmax Measured?
    • The simplest way to calculate Xmax is to subtract the thickness of the top plate from the height of the voice coil winding and divide it by two.
    • If the coil attempts to move out of the gap (determined by the top plate thickness), the magnetic field weakens, causing non-linear output and distortion.
    • Xmax values vary based on the type of driver (tweeter, midrange, subwoofer):
 
Xmech / Xlim

Xmech (also known as Xlim) refers to the maximum mechanical excursion of a speaker or subwoofer. Let’s break it down:

  • Xmech: This value represents the maximum distance the speaker cone can move before hitting a mechanical stop. It considers factors such as the surround and spider (the flexible components that support the cone).
  • Xlim: It stands for Maximum Excursion Limit, and it’s essentially the same as Xmech. Both terms refer to the point where the cone can no longer move further without risking damage.
In summary, Xmech or Xlim indicates how far the cone can travel before encountering physical limitations. Beyond this point, the speaker may experience distortion or even damage. So, it’s a crucial parameter to consider when designing or evaluating speakers and subwoofers. 🎵🔊
 
Ow damm thanks! This was so interesting to read!

For budget and drivers.

I'd love to use these ciare ndh 18-4s drivers that i already have, but i do have to recone them which costs 169€ if i do it myself and 255€ if i let a local pro handle it.
(I have 6, but at least 1 has magnet shift) These drivers are rare beasts i think. This repair guy said he can fix magnet shift for 100€.

Although im planning on building a big stack, so i will have to buy other drivers in the future with thieleparameters that match the cabinet.

I Will use regular bb/bb grade hardwood multiplex instead of birch because here in belgium its 50€ for regular hardwood and 80€ for birch. This means budget for wood is nothing to worry about. (1220x2440mm)

For drivers I'd like to stay under 300€ max 400€ per piece. I like regular rcf lf18g04's and similar drivers which you can buy from "tlhp" (website) for 275€ a piece (new).

For the moment im just planning on building 4 subs and i'd prefer to stay around-under
1500-2000€

Thanks for the education!
 
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Ok, based on your website and budget of max 400 per driver
( nice filtering on that website !! )
i filtered the drivers by XMAX , BL and FS
the below drivers will fit in almost any horn as they have strong motor (BL), decent xmax of 12mm minimum and low FS

and are where you can get them at a decent price and free shipping i guess ?
this one is a BEAST !!
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frugal-phile™
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What Is Speaker Xmax?

Note that there is no fixed specifications for xMax, so only drivers from the same maker can usually be compared. And it tells you nothing of xLim

Important but not something to get obsess over.

distortion and undesirable outputs

Low distortion is something, but Geddes has shown that what we actually measure has to be a really big number (ie >20%) before it really starts to impact the sonics.

dave
 
Looking at those drivers, the cheapest option is the most attractive, so i wonder, comparing the rcf ln19s400 and lf18x401, how big of a difference will 100€ make?

Is the ciare ndh18-4s not an option? If not ill probably use them for my 1850horn kicks

Also do you think it will be nessecary to make an extra thick driver plate, if the xmax is 18mm, maybe a double driver plate?
Screenshot_2024-04-24-22-31-24-173_com.google.android.apps.docs.jpg


Im also convinced that adding extra bracing is smart, i would put the bracing on green highlighted spaces (see second image)

Screenshot_2024-04-24-22-32-08-684-edit_com.google.android.apps.docs.jpg

I don't know if ventilation is necessary, i know a lot of people who push their sbh's to their maximum but don't have any ventilation.
Tho if necessary, would adding 2 pvc pipes from the chamber to the rear of the cabinet be valid?
Or either metal plates on the sides of the chamber? (Pvc pipes preferably because its cheaper and easier)
 
Fraksel,
Lord Sansui already answered what about closed chamber designs like the one you put your sight on....
when those plans were designed , the drivers were only around 6-8mm xmax, and the power they can take was around 300- 600 watts
so no big problem with overheated coils...

now with todays drivers in excess of 12mm xmax and drivers taking up to 4kw
heat is a big factor.

that being said, once you set on a driver , if it was not the original driver the plan was made for, we need to sim your choosen driver
to see if not deviate too much or give an acceptable response.

so as Lord Said, i advice you to choose another design that is not a closed chamber
that one resembles the Cerwin Vega L36 or Yorkville LS1208 , closed chamber horn subs
if i am not mistaken they are around since 40 years now

a proven design can be modified to suit your choosen driver
but that is beyond my HornResponse skills

but i can use plans already made and test drivers

so... let's do not overcomplicate things
get rid of your closed chamber design
and made this one
much simpler and as a bonus you will not suffer overheating on the coils cause the driver
coil is facing the oustside ( like Danley TH 11x series )

it is a design by Jim Bell that was already built and tested for a High School outside sports stadium
you make 8 of these and you will blow the socks off your EDM crowd

it was made for the Eminence Kappa 3015LF (15" )
bit since is >600Litres cabinet it can hold an 18"
i simmed the B&C 18TBX100 and fits like a glove

I envy you!!!! cause where you live it cost 280 , over here is 50% more!! GEZZZ hahaha
ok
so
get 8 drivers 18TBX100-8 ohms
get a 4 channel CVR so you run 2 cabinets per channel... ( 8 cabinets total) with 1 amp
since this TH horn is very sensitive you will only feed the drivers 300 watts to reach xmax at 30HZ
with the smallest 4ch CVR you can get 140dB's to your crowd
you have an idea how LOUD 140db's are @30Hz... if you are standing at 10 meters of the rig
you will feel your eyeballs and guts to implode!!!
hahahaha

anyway... here is the sim and the plan .. is it very simple... not that many folds

18TBX100
get 8
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one of this
https://www.canalsoundlight.com/product/cvr-audio-d-1004/
get it where you can get the best price
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now for the sims

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The beauty of the TH design is that you will not have the distortion of the bass reflex cabinets
people who use the double 18's think they are LOUDDD BAZZZZ but actually the are hearing the distortion of the design
plus you need DOUBLE the AMPS and cabinets to hit the same SPL

with Horns you need little power!!
and if you build at least 4 .. then 8.. the 12..!!! MONSTA!!! SISTEM !!!
for 16 cabinets you only need 2 CVR 1004 ( 8 cabs per amp)

just do not forget to set you FILTERS and Limiters!
the 1st thime you make tests... always smell the coils
if you dont sense... you are fine.. and the best is that on this designs
you can actually touch the magnets
also this designs do not suffer overhating
unless you CLIP your amps and feed pure sinewaves crap !! lol

ok.. nuff chat

This is the plan
SIMPLE!!
( add bracing as the original did not show cause it was run around 200 or less watts )

just convert english to metric
and the pics show a 15" driver but cause the baffle size
you can fit the 18TBX100

if you want to learn some
here is the original thread where JBELL STADIUM HORN originate

last but not least some closing words
you can go lower... but you need better ( more expensive drivers ) and bigger cabinets
but WHY going lower than 30Hz! you enter the HT ( home cinema freq area territory )
you just waste power and SPL ( Sound pressure level )
the HIT in your chest bass is not in the 30hz regions... is more between 70-90 hz
Food for thought

have you ever wonder why PA subs are normally rated at 40Hz and 35Hz , just in the past years because EDM and stuff
people want to get lower.

so there you go!!
Build and Enjoy !!

PD.
(Gezz... i had never simmed the 18TBX100 on this one... now i want a pair at least!!)

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