The FR125-Spiral project has begun!

[eVITAERC]

I remember someone at the RAW meet saying that he made a Zigmahornet with the FR125S and it sounds like s***

Al, thanks for the offer! Now I just have to figure out a way to lug that thing to Surrey again...

 

[maxro]

Now I just have to figure out a way to lug that thing to Surrey again...

What do you mean lug? Those were some of the smallest speakers there. Just try moving one of Al's creations.

Max

 

[Masa]

I am still trying to figure out exactly how this "spiral" works. My thoughts so far are:

-I can't see it being a horn, the mouth opening is much too small for it to be effective as a horn at low frequencies.

-I can't see it being a transmission line, the impedance curves shown on Masaaki Takenaka's site don't look like a TL's at all.

-The impedance curve I did find on Mr. Takenaka's site makes it appear as if the "spiral" is acting as a port. That said, I still can't figure out how there can be any real advantage over a standard ported box. If it wasn't for the fact that I have heard these in person you would have a tough time convincing me they work as well as they do.

I agree the "spiral horn" is not a "horn."
I think the behavior of a 3D spiral "horn" can be explained by the Helmholtz resonance. But, it differs from an ordinary bass reflex on the following points.
1) The frequency of the first impedance peak (not an impedance dip) coincides with the "lower limit," or it may be called "tuning frequency."
2) The frequency of the first impedance peak coincides with the Helmholtz resonance frequency if the maximum length of the spiral is used as the length of the port.
3) Many people say the sound characteristics of a "spiral" are markedly different from an ordinary bass reflex.

I think the "spiral" should not be allocated to any existing genre and am still struggling for making clear the principle governing the "spiral."
http://www3.ocn.ne.jp/�`hanbei/eng-whyspiral.html

 

[madstamm]

Regarding the SpiralHorn:

count me in as a builder! Ive been looking for an "alternative" implementation for my FR125s... only have one pair, and it seems everyone's got two and is building bipole TLs!!

so this looks perfect

Also, some might recognize the old (pre 2000) phoenix gold driver "Cyclone", which used a vane-motor to displace air:

Link to Cyclone Picture/Specs Here

...could one say that they used the "spiral horn" concept? I realize its a bit far-fetched, but... ?

I have to admit to not checking out the spiral horn site extensively yet, but the crazyness-factor sure got me going here

greetz,

mike

 

[vadi]

Hi!

I would like to build this speaker. I would like to use them for home theater along with a sub.

I'd like to use them for the surround channels while the main and centre are 125FRs biamped with Adire Extremis 6.8 speakers. Do you think that's ok?

How loud do they play? I don't want nothing earshattering and my room is not very big (max 20qm).


Regards,

Sladjan

 

[zzzzzzz]

i too would like to make something like this useing zt-104 that is in this link http://www.concept-intl.net/download/subwooferspecs2005.pdf

the speaker i'm going to use is a sub and i'm going to use a big amp .so i'm thinking a loaded spiral horn that folds over to have a pipe inside a pipe, but i do not know how to do the math . so can you help me with the math ?

 

[jkeny]

Resurrecting an old thread, seems opportune as the last poster here was zzzzzzzzzzzzz.

WoodturnerFran built twopairs of these speakers but using the newer angular spiral design rather than spiral horn design. One pair featuring Jordan JX92S drivers and another pair with Fostex126E drivers.

Both sound excellent and I wondered if the same mathematics apply to angular spirals?