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-   -   Olsen Nagaoka style horns: half as high, double wide? (http://www.diyaudio.com/forums/full-range/185832-olsen-nagaoka-style-horns-half-high-double-wide.html)

chazdrumzalot 26th March 2011 04:05 PM

Olsen Nagaoka style horns: half as high, double wide?
 
Suppose you can't accommodate a 6" tall horn in your living space. What happens if you take one of these designs, cut them in half, and place the horns side by side? Compression chamber, horn length, throat surface area would all remain the same. Would the end result perform similarly? Obviously the soundstage might be affected, as people always comment about the value of floor/ceiling loading....

Thanks!

Chaz

planet10 26th March 2011 05:15 PM

It is something i have woundered about too.

dave

Scottmoose 26th March 2011 05:42 PM

As they were designed with the over-under configuration & radiation pattern specifically in mind, you'd be (considerably) better off with something that was actually designed to be short[er] in the first place. They would not perform as intended. If you want a manifold horn, you may want to look at something like the Nagaoka D-58.

rjbond3rd 27th March 2011 12:20 AM

In my extremely limited experience:

1. Sort of a false premise, isn't it? How could you not have room for a tall, skinny speaker, but you -would- have room for a short fat one?

2. The double-mouth horn is a bifurcated design, i.e. a single horn divided into two. The short, fat one should be equivalent except for the baffle step point (a pretty major consideration). Presumably, the bandwidth of the horn was calculated to compensate for baffle step. Change the width of the baffle, and now the horn's bandwidth is not so gracefully matched up to the baffle transition "zone".

3. It's not -that- hard to calculate a half-way decent horn (much harder to do a near-flawless one). On the other hand, there's a lot to be said for building a proven design, at least at first.

4. If you really wanted to chop up a horn design, you could leave off the top part and leave the bottom as-is. The first double-horn that I am familiar with was the opposite -- the designer took a Fostex horn and simply doubled it (or so I've read).

5. I'm not sure ceiling loading is such a big factor, honestly. Why not sim this in MJK? He has specialized worksheets for single and double-mouth BLH's. If you're like me (a slow learner), use AJ Horn which has a very simplified user interface (in my opinion) but is not calculating as many factors.

chazdrumzalot 27th March 2011 07:05 AM

Hey Rjbond3rd,

1. It's not a matter of footprint, but height. a 6' tall speaker makes a pretty big statement, whereas I don't think a 3' tall speaker - even a wide one - will be so obtrusive in my space. Fact of the matter is that either speaker might be a bit too big for me.

2. Your presumption abut BSC may be correct, but it's not implicit in the design. Maybe someone could comment on this? It would be useful to know in any case. The published responses don't show BSC so far as I can tell. In fact, I had almost hoped that widening the design would prove advantageous in this respect!

3. I know you're definitely right about that. I guess the problem for me is that I chose to buy a pair of drivers with very few published designs (TB w5-1611) and I'm trying to exhaust all the possibilities before I make a build.

4. This is an attractive idea but I thought it might compromise the performance of the horn more than my suggestion. In any case, it looks like Scott has made it clear that neither idea will prove very fruitful compared to the original design.

5. I would love to use the MJK worksheets but, well...I'm a mac. I know that those worksheets would provide me with hours of entertainment as I am constantly studying existing designs and eager to experiment. I've read some of the technical papers on his website but they are near impenetrable for me, unfortunately.

And thanks Scott for chiming in on this. I'll take your word for it that this concept won't work.

planet10 27th March 2011 07:44 AM

Quote:

Originally Posted by chazdrumzalot (Post 2517902)
...I'm a mac.

If its an Intel Mac you can run Windows a number of ways ... or run WINE (crossover mac, the slick commercial version) which doesn't require Windows to run (well behaved) Windoz SW.

dave

rjbond3rd 27th March 2011 07:00 PM

Hi Chaz,

Quote:

Originally Posted by chazdrumzalot (Post 2517902)

2. Your presumption abut BSC may be correct, but it's not implicit in the design. Maybe someone could comment on this? It would be useful to know in any case. The published responses don't show BSC so far as I can tell. In fact, I had almost hoped that widening the design would prove advantageous in this respect!

Not sure if you're referring to a specific design? But a BLH basically has a "mechanical crossover" from the driver's forward radiation, down through the baffle step transition zone, down to the horn's upper frequency response. You want that to be as flat as possible. It is possible with computer modeling to get it right (more or less). You might decide to sacrifice depth of bass to get flatter response, or vice versa.

Quote:

5. I would love to use the MJK worksheets but, well...I'm a mac. I know that those worksheets would provide me with hours of entertainment as I am constantly studying existing designs and eager to experiment. I've read some of the technical papers on his website but they are near impenetrable for me, unfortunately.
If you love BLH's, you have to get them!

Install the free VirtualBox software for Mac, then install Windows. Now you can start Windows as if it were a Mac application. (But don't go online inside the Windows environment unless / until it is hardened).

Luckily, you don't need to understand MJK's whitepapers to use his software because the software is very much "fill in the blanks." He answers all questions on his Yahoo group. Give the other tools a spin as well (AJ Horn, HornResp, Akabak).


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