4th BPH order I think ??

[sketchyphish]

Hello fellow builders,

I have a 2 Fane Classic 18/125's (Fane CLASSIC18/125) that i got from a market for £15 and would really like to use them as i dont have the money for more xpensive subs, but do have the materials.
I have decided to build a three way system to get me started, also including some H&H 1200E's from some old H&H cabinets i also got cheap.
Im currently trying to use hornresp to design some horns for the mid range, but im sure i need to work a little more on it as i can only seem to get a response between say 250hz and 800hz for a tractix design on the 1200's. Tops i havent decided on yet.
Now my main question is about the Fane single 18" folded horn design from the Fane Loudspeaker Book (http://www.4fsc.co.uk/blue-room/Fane...es%2034-41.pdf). I have read a lot about horns an well even when i build 2 Im not gonna get the low ends i would like. This is just inherent in horns of such a small size. I would like these to cover the whole bottom end until i get money for better speakers.
Ive been reading about Hybrids, and wondered that if i extend the lower part of the cabinet by ~43cm (keeping the existing dimensions and extruding downwards) this should give a rear chamber size of ~328 L for the sub, which according to Win ISD is adequate to give a relitively flat response with a cut off of 38hz. This will be ported with three 11cm diameter ports of 9.7cm length.
Will this design work to achieve a good coverage horn with extended low end......or am i missing something vital ??? i.e i dont think it is a 4th order because there is no sealed chamber and it could be a 6th but has no front chamber......? Maybe just a horn loaded vented enclosure ?
Any advice on this would be greatly appreciated as i am really up for building some cabinets that will cater for what i need until i get some revenue in from the system for better designs and components.

P.S any ideas what i can do for the 1200's other than a mid horn as hopefully the 18 cabinet will cover up to ~250-300hz and im looking to go three way as i said.

Thanks for reading i know its long

[epa]

hi sketchyphish.
the horn you refering to is a bit outdated.
even the fr graph shown is a bit optimistic.
+ its over 2 sheets of ply.
why not try on a tapped horn
it seems this driver wil work nicely in a tapped horn.
altough i'm doubtful on these given ts parameters.
do you have a pic of it?

tapped horn

tapped horn

[sketchyphish]

Ive got some pics but dont know how to attach them from my hdd seems only a url will do...... I know these cabs are old but i was looking for something that would match the drivers. Its only because of the low efficiency of ported enclosures that i havent gone with the designs ive made in Win ISD. Horn's seem to through further and give a higher efficiency, based on the fact that these are low wattage drivers i want to get the most out of them.

Im not looking for KW's of power as i am basically designing a lower powered rig to run from renewable sources so if i can get the whole lot to be about say 1k then great, but i do want the most output for the power.

I dont really understand the principle of Tapped horns and therefore wouldnt know where to start with designing one, i thought if i use a cabinet designed for this driver and then extend and port the rear chamber, then i can achieve a lower bottom end than the cabinet allows for on its own.

I did design a 6th BP box before which worked quite well, but upon renting it out the speaker came back damaged (very rough sounding) so i ditched it. I had heard that the unequal loading of the driver in this condition could cause damage to cones that are not quite up for the job.
Again any help on this would be great im up for any suggestions to achieve what i need.

[epa]

a tapped horn has some advantige .the rear wave of the speaker is used.
this could give a max of 6db over a basreflex(in ideal situation)but a bigger cab.tough smaller than a flh.
especialy when used in singles the th is a winner.
for example i have symed your speaker in the bottem link in post 2.
the whole plan is in that toppic, its 1 sheet 5'*10' + a few extra bits.
if you want to try that i can assist you,if u want.

btw those peaks @160 and 240 hz are non existend in real live.

now to be clear
witch way where you going to extend?


i can sym it for you,then you can decide.

[sketchyphish]

Well thanks for the info, of course i would be interested in you helping me with this cabinet. As for your last question i would be extending the cabinet in the direction of the red area, as to increase the rear chamber of the sub to about 328L.
I could get a copy of cad software but of course this is going to take a while to get used to, and well actually taking figures from hornresp and using tham again is another challenge.
I understand the principle of a tapped horn is by the time the waveform reaches the mouth the rear of the driver will be producing the second half of the wave and therefore add to it producing more db. anyways if im wrong im sure i can read more.
To understand i will be using the cabinets as either a stereo system either side of the crowd, or of course my favourite, stacked centrally. Dont know if this will help the horn loading to go lower if stacked, but depends on the gig and the type of music wheteher they want a clear stereo/bineural separation or not.
The only other problem with using existing cabinets is the tuning of the cabinet to the driver for maximum effect. Has anyone looked at the golden ration/fibonacci sequence for horns ? this being another project i hope to get on with, kinda snail shell bass bins (massive i know but i will build them one day) scratch that lets just stick to the point.

Thanks again.

[epa]

mono-ing subs is always a good ideer for several reasons.but idealy you cross them low and steep @100hz or so.
i wil put your ideer in hr in the next couple of days.

[epa]

hm you'r spot on,extending it 40 cm give you ~320 ltrs
the cab wil then be 700 ltrs
3 ports 15 cm long.324 ltr vrc.
i just eyeballed/guestimate the sections so it may change a bit after some cad-ing.
here is what ive got so far.

[bjorno]

FYI,

IMO,Any TH-sub that works with a low compression-ratio(<2:1) is suitable for to be stuffed with damping material to achieve superior SQ in comparison if not.

I found this driver qualifying for this approach if single folded(+cross-bracings)only and stuffed(max 0.25lb/ft^3=~4kg/m^3) to max a third of the line counted from the throat S1 area.

b

[epa]

hi bjorno ,does this only aply to a single fold th ?

[jogi59]

A small remark.
The 9.1mm Xmax in the datasheet is Xlim
The usable Xmax is around 3-4mm