Speakerplans.com Homepage
Forum Home Forum Home > Plans > New Projects Forum
  New Posts New Posts RSS Feed - **terra horn**
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

**terra horn**

 Post Reply Post Reply Page  123 7>
Author
Message
minaximal View Drop Down
Old Croc
Old Croc
Avatar

Joined: 26 September 2004
Location: United Kingdom
Status: Offline
Points: 1727
Post Options Post Options   Thanks (0) Thanks(0)   Quote minaximal Quote  Post ReplyReply Direct Link To This Post Topic: **terra horn**
    Posted: 01 June 2005 at 9:45am

from the soundcheck thread..

yep, its my own "little" beastie, 3.4m "supercurved" smooth constant expansion 26hz fc hyperbolic horn, loaded with pd1850, taken best part of a year learning about horns and reading the wise words of other whilst loitering round places like this.. and then the cutting... let alone design n learning autocad etc

anyway yep we like our noise, but it was tested at points, as much as could be done with a bridged peavey cs1000

i did wonder if anyone here would have noticed hehe

i'm sure theres a few that may b interested, trying to get construcion photos sorted on a website.. maybe start next week

al



Edited by minaximal
Back to Top
rinky View Drop Down
Registered User
Registered User
Avatar

Joined: 02 March 2004
Location: United Kingdom
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote rinky Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 11:03am

it looked a bit different to say the least. is it possible to stack them?

Back to Top
minaximal View Drop Down
Old Croc
Old Croc
Avatar

Joined: 26 September 2004
Location: United Kingdom
Status: Offline
Points: 1727
Post Options Post Options   Thanks (0) Thanks(0)   Quote minaximal Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 11:55am

well, they have a large mouth (only built one so far tho) and i designed them to work in pairs side by side or for a bit of serius bass with four; on their sides, two on bottom two on top. having said that one seemed really good with a bit of eq in 2pi, so should be absolutely fine in 0.5pi due to boundary reinforcement and cabin gain.

oh and it took 3-4 of us to move them cos i hadnt had time to put handles on yet.. hopefully tonight, when theres enugh of us at home to lift it back up the stairs from the van

the only problems with a stack of four on their side would be u cant sit in the middle, which was very nice indeed. (30hz massage at 130+db 18mm from your back, lying down in one) and everything needs strapping down, or they might walk away..



Edited by minaximal
Back to Top
rinky View Drop Down
Registered User
Registered User
Avatar

Joined: 02 March 2004
Location: United Kingdom
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote rinky Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 1:10pm

have you got any pictures? it looked like the horn path was cut from one peice of wood - it's difficult to explain.

was it folded in the normal way? or more of a curved horn (like a trombone)?

Back to Top
minaximal View Drop Down
Old Croc
Old Croc
Avatar

Joined: 26 September 2004
Location: United Kingdom
Status: Offline
Points: 1727
Post Options Post Options   Thanks (0) Thanks(0)   Quote minaximal Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 2:14pm

here is a cad screenshot. the red line is disecting the outer center of the rear chamber.. the horn profile and this rear chamber section are cut from one sheet of ply per side.

Free Image Hosting at www.ImageShack.us" border="0" />

or http://img205.echo.cx/img205/1898/terrahorn7ie.png

its not teknically folded as such,  you can see its curved around the 2 corners, i havnt read any research,  but as far as i can imagine sound waves can propagate with less friction/turbulance or eddys round a smoothed corner rather than the bp effect of right angled corners in most folded horns.. dont forget standing waves and back reflections too, reducing efficiency.. which isnt taken into account in horn response... this may even lead to the possibility of a much higher crossover point if so desired, because it more resembles a "warped" straight horn. i havnt as yet tried it above 90hz.

got loadsa photos, but theyre all on my gf computer.. half in sequence of construction. still waiting for slide film of the horns escapades at the teknival to come back..

Back to Top
Timber_MG View Drop Down
Registered User
Registered User
Avatar

Joined: 27 March 2004
Location: South Africa
Status: Offline
Points: 1454
Post Options Post Options   Thanks (0) Thanks(0)   Quote Timber_MG Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 2:47pm
There is actually a tool that gives you a vry god optimum AND exports to dwg!!! Go to cornu.de -> forum -> FAQ and look for WH Geiger's horn folding spreadsheet.
Back to Top
minaximal View Drop Down
Old Croc
Old Croc
Avatar

Joined: 26 September 2004
Location: United Kingdom
Status: Offline
Points: 1727
Post Options Post Options   Thanks (0) Thanks(0)   Quote minaximal Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 3:23pm
yep seen it/used it, it is a great little tool, but that is still assuming a degree of curvature is involved.. in comparison to ur average flat paneled fold, and it tends to go a bit crazy with long curves! (also 1 curve at a time)

Edited by minaximal
Back to Top
Timber_MG View Drop Down
Registered User
Registered User
Avatar

Joined: 27 March 2004
Location: South Africa
Status: Offline
Points: 1454
Post Options Post Options   Thanks (0) Thanks(0)   Quote Timber_MG Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 3:35pm
That is where you need to start thinking about the shortest wavelength (i.e. at the top of your bandwidth and half-one octave above) and make a compromize generally on the inside radius, do 5cm really matter when you have a 1/4 wavelength of (eg) 40cm @ 200Hz?

I just use it to get the fold close theoretically and then shuffle arounda  coupl eof parameters, including "compromizing" the last bit of the horn (hornresp with conical equivalents and for eg. a faster terminus). The first bit is the most important and due to the low cross section simplest to fold well.
Back to Top
Timber_MG View Drop Down
Registered User
Registered User
Avatar

Joined: 27 March 2004
Location: South Africa
Status: Offline
Points: 1454
Post Options Post Options   Thanks (0) Thanks(0)   Quote Timber_MG Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 3:36pm
I also tend to think in terms of preserving the same volume of the horn contour where possible with the constraint of 1/4 wavelength
Back to Top
tb_mike View Drop Down
Old Croc
Old Croc
Avatar

Joined: 01 October 2004
Location: New Zealand
Status: Offline
Points: 2744
Post Options Post Options   Thanks (0) Thanks(0)   Quote tb_mike Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 5:46pm
3.4m with 26hz Fc ,thats what im talkn about! Bass therapy!
Back to Top
minaximal View Drop Down
Old Croc
Old Croc
Avatar

Joined: 26 September 2004
Location: United Kingdom
Status: Offline
Points: 1727
Post Options Post Options   Thanks (0) Thanks(0)   Quote minaximal Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 8:27pm

@ timber, yep i'm sure your right talking wavelengths, but have you ever tried tugging a ratchet strap round a 180 degree panel, then around a smoothed curve.. i can imagine pushing air being the same: less friction and turbulance and reflections.

anyway it is kind of less practical but looks the  bollox, and is less "compromised" 

@mike i'll get some photos sorted soon

Back to Top
JD01 View Drop Down
Registered User
Registered User


Joined: 23 August 2004
Status: Offline
Points: 818
Post Options Post Options   Thanks (0) Thanks(0)   Quote JD01 Quote  Post ReplyReply Direct Link To This Post Posted: 01 June 2005 at 8:28pm
I wonder how long the PD1850 will last. The loading is serious in such a long horn. Even the two special made 12" speakers in the EAW KF940 couldn't take it (and 12" cones are much more stable than 18"s are....).
Back to Top
 Post Reply Post Reply Page  123 7>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 11.01
Copyright ©2001-2014 Web Wiz Ltd.

This page was generated in 0.359 seconds.