suggestions needed!!!

[superfunk]

Hi, i'm new in this forum, so please be kind..
I've been thinking for long time on building a horns set-up with my hands.
This would be my first experience with horns, so i think it won't be clever starting with a complicated 4 way system and phase related issues.
I've been reading on some theory about horns, so i came to these conclusions:
-20cm drivers are a good compromise
-the diaphragm works better when loaded both sides (maybe a folded horn for back load plus a front horn)
-the trantrix shape is more suited for home use than the exponential shape.

Am i right with these assumptions?

Talking about a single horn, my thoughts were that to achieve a cutoff frequency of 56Hz with 8 inches diaphragm, the throat at the front horn should be of not less than 12 cm of diameter, the final mouth of about 90 cm and the length of the horn of 26 cm circa.
But, again... i worked out these measures, considering a single horn with a bottom cut off frequency at 56hz. Please feel free of telling me i'm wrong with these data.
This size would not be extremely big for my room which is about 6x5 metres, and also, it would be easier fabricating two fiberglass horns (for me) than two mdf folded horns cabinets, but i suspect this is not going to sound good, because of the fiberglass and because of the lack of load on the back of the driver.
If i double load the driver, i can reduce de size of the front horn, am i right?
Here is where my problem starts: going with the folded way, theory and formulas don't work anymore, and i am not knowledged enough to design my own back folded horn.

Have you got any suggestions for a folded back horn to use with a front tractrix together?
What do you think about this project? should i put it in the garbage?

p.s.: i don't have any idea about the cost of such a project, has anyone had similar experiences?

Forgive my confused fenglish.
Francesco

[Angelo]

Originally Posted by superfunk

I've been reading on some theory about horns, so i came to these conclusions:
-20cm drivers are a good compromise
-the diaphragm works better when loaded both sides (maybe a folded horn for back load plus a front horn)
-the trantrix shape is more suited for home use than the exponential shape.

Am i right with these assumptions?

hello Francesco

if you want a 3 way system, you might think about following possibilites :

make something similar to Avantgarde uno or duo:

use a pair of 10" woofers , direct radiators, to work up to 250hz.
a good candidate might be a Beyma 10MWNd in a ported box, and active drivern with a mosfet class D plate amp

You take a 5,5" paper cone driver, like the Faital M5N12-80 and load it in a tractrix horn with 65cm diameter mouth diameter, a horn similar to this one :

http://cgi.ebay.de/Spheric-Wave-Trac...#ht_1063wt_939

http://www.audiovoice-acoustics.com/...read.php?t=842

and cross it to a 1" compression driver in a small tractrix horn with ~ 7 to 8",

http://cgi.ebay.de/Spheric-Wave-Trac...f#ht_852wt_939

and use a compression driver, like a BMS4540nd, or Celestion CDX1-1425
diameter. Time align all channels, and use a simple first order crossover at 1500hz between the mid channel, and tweeter, highpass the 10"er second order at 250hz, and the lowpass the woofer 18db with the plate amp.

Another possibility would be to use a Altec 414-8A in a ported box, preferably a onken design, up to 800hz, or 1khz, above a 1" compression driver tractrix horn, up to 10kzh, and a supertweeter above.

a ready to gow , low budget system, might be interesting for you as well, is the Visaton Menhir :

http://www.lautsprechershop.de/hifi/.../menhir_en.htm

Talking about a single horn, my thoughts were that to achieve a cutoff frequency of 56Hz with 8 inches diaphragm, the throat at the front horn should be of not less than 12 cm of diameter, the final mouth of about 90 cm and the length of the horn of 26 cm circa.
But, again... i worked out these measures, considering a single horn with a bottom cut off frequency at 56hz. Please feel free of telling me i'm wrong with these data.

i guess you mean a basshorn with 260cm length. The problem you will have is, that you wont be able to have usable output above 150hz. And you will need to compensate electronically the timedelay of such a long basshorn, which deteriorates the sound.

A interesting small basshorn with 8" woofers is Bill Fitzmaurice' auto tuba :

http://billfitzmaurice.net/autotuba.html

another possibility would be to use a 8" woofer in a backloaded cabinet, like this one :

http://www.audiovoice-acoustics.com/...read.php?t=300

and use separate mid channel, a 1" compression driver with tractrix horn, and a tweeter above. You could cross the basshorn at 1500hz, and still have nice output down to ~ 40hz, through the backloaded bass horn.

This size would not be extremely big for my room which is about 6x5 metres,

you have still a quit reasonable roomsize....

If i double load the driver, i can reduce de size of the front horn, am i right?
Here is where my problem starts: going with the folded way, theory and formulas don't work anymore, and i am not knowledged enough to design my own back folded horn.

you will have time delay with the backloaded horn. So that is a compromise to be taken into consideration. A direct radiator in the woofer section might be the best solution for your case.

p.s.: i don't have any idea about the cost of such a project, has anyone had similar experiences?

that depends very much on what drivers and components you will choose.
See first, how much you have to spend, and then figure out what might suite best to you.

Angelo

[superfunk]

thanks Angelo for the suggestions!
i think i'm not experienced enough to start with a 3way set up, the phase issues kinda scares me
i was more inclined into a single 8" driver loadet both sides, rear and front..
that's was my first idea.
i think something like your Piccolo would fit the bill.
as for the drivers and budget..
my idea was starting with something like fostex FE206 (200 euro circa).
Audio nirvana also are very tempting drivers and cheaper too! but i don't like the idea of buy from america and pay half price for shipping and import tax, it's just a waste of money..
in Italy we have Ciare, but i don't know if they are good or not.
Fostex come in europe from japan through germany, so the shipping from germany won't be much.
my budget is about 800 euro (both speakers) for something non professionally finished, then i can upgrade it with a supertweeter when i will have more founds.
do you have some suggestions for drivers in the area of 200-300euro for the couple?
if i will have to make a horn for medium freq, i will try with thick fiberglass first, and if i like it, i will choose a different material.
basically i'd like to do something upgradable in few steps.

my system is nothing esotheric:
technics sl7 linear tracker
technics sl 1200 with audiomods tonearm and at440mla
technics sl 1210 standard with adc 990
bellari vp129 (riaa preamplifier)
trends audio ta 10.1
and i have a couple of '80s integrated amplifiers to push occasionally some big Leak sealed speakers...

i think i spent too much money over the years in source (as you can see), but i can't help, i have a fetish for technics 'tables..
anyway, i'm convinced that speakers are the weakest point in the chain and the more sensible components to upgrades.
since i'm not a big fan of big bucks bass reflex...
your piccolo seems to be what i need, is it too much asking you for some plans?

[Angelo]

hello Francesco

the Piccolos are fine sounding speakers, but do not reach hand on the Audax 3 way system, i built recently :

http://www.audiovoice-acoustics.com/...read.php?t=833

i spent 800 Euros to build them, everything included. The speakers are very rare, but you can find equal modern drivers, with similar performance :

http://www.audiovoice-acoustics.com/...read.php?t=672

with that budget, i would recommend you to go this route. I have made the crossover according to original audax plans. You would find with ease information how to make the crossover, its not that complicated.

I personally like the dual concentric solution. The 8" Radian sounds amazingly good for its size. If i had to go the single driver route, and size would not matter, i would give probably preference to
a 12" Radian coax , like this one :

http://cgi.ebay.com/ws/eBayISAPI.dll...#ht_898wt_1165

[superfunk]

all this is making me very confused!
that 3way system looks good, and if you say it sounds good too... it should be a no brainer!
but i think it will take long time to get all those drivers for a good price!
now i'm messing with too much ideas, because before reading your answer, i had bidded on a fe206 on ebay, don't know if i will win the auction.
how much did you spent for the piccolo? (if that's is not a secret information).
anyway, i think i'm better to see what drivers i will find and then think about the rest.
at the moment i'm bidding for those fostex 8" and for some visaton 12".

[Angelo]

Francesco,

you can cancel any bid, if the auction goes still for more than 12 hours.

http://offer.ebay.com/ws/eBayISAPI.dll?RetractBidShow

there are many possibilities to built up a very fine sounding speaker system, even with your budget. Going a 3 way solution, you will indeed need a little more work to build up a system, and making the right crossover for the choosen components, will demand a little research, and practical ability, but nothing, even a beginner is not able to do. If you want little work, then the Radian 12" er is a no brainer - its a very fine sounding dual concentric driver, and even if you will not make a backloaded horn, in a right sized closed, or ported cabinet, you will get enough low output.

[superfunk]

Hi Angelo, it was too late:
The auction for the Visaton was nearly ending, and i've lost the auction for the Radian.
The Radian went too high anyway, and shipping price was above 170dollars + import tax + driver's price... so it was not affordable at all.
Now i'm waiting for the Visaton to ring my bell and then i'll be ready to play this game...


Because i've also found a cheaper flat (finally) and will move soon, my needs have changed a little bit.
My new room will probably be 3,5 x 5,5 metres (2,60 tall).
I'm thinking to mount my system on the short wall and to listen at about 4 metres from it.
In such a tiny room there's no need really for big SPL, but... i still wish on a good performance from at least 35Hz to 20KHz (if it can go lower, i surely won't moan).
I'm not worried about WAF, because i live alone, and so i don't have particular size-design limitations (they just have to fit into the room, than it's fine).
I'm already taking into consideration some bass traps in the corners and ceiling, and the bed itself will be a big bass trap.

Last weekend i went to an audio convention (if that's the right word) and had the chance to listen at different systems.
I was very impressed by two Systems: one with "Avantgarde Solo" and the other with two set from "Horn Manufaktur"
the models were these two:
http://www.hornmanufaktur.at/it/products/a90.html
http://www.hornmanufaktur.at/it/products/a100.html
As you know, the Avantgarde has a bass reflex on it's back and uses a specifically designed built-in amplifier, with a moulded frequency responce, so this is not possible for me to build
The other two speakers are backloaded horns, but they use their own drivers.
Do you think it's possible doing something similar with the 12" Visaton?
I like the Dallas 2 design a lot, but they're for 8".

[Angelo]

Francesco

i think the Dallas would be a good choice. I would just make it a littlebit larger, to fit the 12"er. A other design which you might consider is the german
" das viech " :

http://www.hifi-forum.de/viewthread-205-165.html

and the Frugal-horn designs :

http://www.frugal-horn.com/

to get down to 35hz, you might add a sub.

[superfunk]

Hi Angelo.
i was not sure about building a horn studied for 8" and cut a bigger hole to fit a 12"...
i don't know, but i'm not sure the needed lenght of horns are the same.
also, i've tried to put those drivers in a OB with some scrap wood i had liing around, just to taste them.
i kept switching between my headphones (akg k141) and the speakers... then compared them with my 3-way Leak..
they just sound wrong to me, there is not deepness of the instruments, they're very very loud, but not "airy". also, bass doesn't seem to go very low, but maybe the Leak are too good in this area.
maybe these drivers are not well suited for horn loading...
i have tried to put their specs on a onken calculetor, to see if it was worth, but it ended up they're not suited for onken too.
maybe the only way with it is to put them in a sealed box, and then add up a horn tweeter... maybe...
honestly, i'm loosing any hopes with it, i think i just bought the wrong stuff

the specs are:
Fs 40Hz
Qms 3,59
Qes 0,84
Qts 0,68
Vas 180 litres
Sd 511 cm^2
Mms 33 grams
B x l 8,2
L 1 mH


i searched in the web for possible encousures for "big" drivers like 12" and 15" and it looks to me that i really have to choose between a onken and a vott (a7?). but not whith these drivers!
anyway, now i learned the hard way that i should consider specs before buy something, instead of just buy and then "let's see what to do"...

Francesco

[Angelo]

hi Francesco

what is the model number of your speakers ?

http://www.visaton.com/de/chassis_zu...and/index.html