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In the Forum: Horn-Loaded Speakers
In the Thread: Jessie Dazzle Project
Post Subject: Some points regarding your comments.Posted by Romy the Cat on: 8/5/2007

Jessie, I pulled posts from Macondo Axioms thread and encapsulated them onto a new thread dedicated explicitly to your project. I hope you do not mind.

 jessie.dazzle wrote:
This would impose a design that is not round but octagonal. It would require the making of a forming tool (no big deal). 
Pros : Can do it myself Cons : Octagonal horn section

I do not think that “not round” will be a problem. For those types of frequencies a small deviation from spherical shape should not affect a lot. Furthermore, do not have round shape will be superbly beneficial for that midbass horn as you will have more ease to hang it. Also, and it is very-very important, the bottom line all the midbass horn will a short straight line instead of a radios. That will enable to lower midbass horn relative the top of the lower midrange driver. If to be too “obnoxious”, then I would even conceder to make a small bite-off at the bottom of the midbass horn in order to bring it even lower. However, if you go for non-spherical shape then I would strongly encourage making non-even amount of segments. So it should not be eight segments but nine or eleven, in order to eliminate any near-parallel surfaces inside the mouth of the horn.

 jessie.dazzle wrote:
Frame is very adjustable. All horns except the Upper-Bass (which has only axial adjustment) are vertically and axially adjustable on sliding blocks. A small modification would allow tilting them down (or up), but for the moment it is not in the plan. The horn supports are independent of the main frame, meaning the horns can be placed in any order desired; different supports can be added later.

Very Nice! Sort of plug-&-play in a loudspeaker design. Very very very cool!

 jessie.dazzle wrote:
9) Potential problems with near-field listening :
I prefer a near-field set up; which is good, because I am forced to use a near-field setup.

When you (Romy) say :
“...the output of a lower midrange horn would be too prevailing”...

Do you mean the output from the 180Hz Lower-Mid will be coming from a point that is too high (or did you mean to say the 45Hz Mid-Bass horn)? Would tilting down the 180Hz horn help this (I understand it would restrict listening to one point)? 

The point that I was making is that lower midrange horn is sitting, at least in my case, right at the height of my ear. So, when I was blubbering that Macondo can be integrated from as insultingly close distance, I implied sitting position. If to stand up at extreme nearfield position then obviously the lower midrange horn will be shooting right at your face and the total balance of sound will be very incorrect (I low-pass my Fundamentals Channel very shortly). So, you might not be able to stay in front of your speaker at nearfield and to conduct the music :-)

 jessie.dazzle wrote:
10) Integration of Injection Channel :
The frame provides the space to slide in an Injection Channel. I am however trying to avoid this. I would like to get tone from the drivers in the horns

Hmmmm…. OK. BTW, find among your neighbors someone who has an OK sounding Tannoy Red installation and try to listen it… Try to puck those neighbors who do not do anything with driver, crossovers or enclosures. You might find it educational….

 jessie.dazzle wrote:

Upper Mid-Range : Vitavox S2 > 400Hz Tractrix :
From : 3200Hz
To : Open

Lower Mid-Range : Vitavox S2 > 180Hz Tractrix :
From : 790Hz
To : 3200Hz

Upper Bass : Driver still under consideration > 115Hz Tractrix :
From : 240Hz
To : 770Hz

Mid Bass : Vitavox AK151 > 45Hz Tractrix :
From : 60Hz (need parts)
To : 240Hz 

A few comments. Vitavox S2 in 400Hz horn crossed at 3200Hz will sound acoustically much lover. If it is a new plastic diaphragm then it will run all the way to 1000Hz. Therefore the Lower Mid-Range could be cut shorter then 3200Hz. It was very interesting to experiment with it and move the crossover points up and down, letting both S2 channels to work together in mid range. Also, you did VERY good going for Lower Mid-range not 250Hz (as I did) but 180Hz. It was what I am “non-violently” considering to do as well.  If you look at the second page of the following thread:

Then you will see that S2 and 250Hz horn do not tolerated anything lower then 600Hz, third order, with throwing “horn boom” as punishment.

The bold section of:

The driver can handle lower but the horn can not. So, my idea was to do for 170Hz-180Hz horn and drop the crossover point for 500H second order. As you understand with a frame of the fixed height is kind of complicated as it will narrowing the window through which the tweeter might shoot. I still, nonetheless, am considering doing it, perhaps going for exponential profile...

Also, since the tip of your from will me small you might consider also a following arrangement. Sure, you can angle the axis of the big horn more sharply.

The cat

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