LaScala and a Horn or MEH - help me choose

[StabMe]

Hey!

 

Been reading a lot on Klipsch horns and posts by @Chris A got me very intrigued with the MEH aproach. 

 

So i am choosing a concept of my next build for a home system i will be using mostly for 2 channel music and some movies. I want to finally get to that crisp and fast sound that horn system provide, especially in the midbass. The room the system will be installed in is 6 by 10 meters with 3m ceilings (19 by 32 feet, ~10 feet ceiling). Listening position is about 3.5-4m from the front wall and the speakers will be placed in the corner.

 

Now, i like the idea of a 2-way MEH, especially based on K402 horn. Unfortunately, i live in a place where those horns are not sold and ordering them from overseas is super expensive, given the currency exchange rate, shipping costs and taxes. So the idea is to make a double flare horn of a comparable size using bwalso's spreadhseet. 

 

The question is - am i going to get that fast and crisp sound with a DIY horn the size of K402? According to the spreadsheet, a horn with a size of 100x64x40cm (WxHxD), horizontal pattern control only goes down to 230Hz. However, ChrisA in his earlier posts on MEH says, if i understood him correctly, that A K-402 based MEH controls its polars down to 100Hz when placed into the corners. Am i going to achieve this with the approach i mention? 

 

Or, if i am after a speaker system that controls its directivity and provides horn loading down to 100Hz, i should better choose another 2-way system with a separate bass bin (La Scala, FH-1 or Khorn)?

 

P.S. Forgive my ignorance if i am asking stupid things.

Edited December 3, 2020 by StabMe

[Chris A]

On 12/2/2020 at 5:35 AM, StabMe said:

The question is - am i going to get that fast and crisp sound with a DIY horn the size of K402?

There is no downside, acoustically, of having a horn of the mouth dimensions of the K-402.  In the Jubilee and other KPT models, the  K-402 only sports a 2" compression driver down to ~450 Hz.  Can you hear the difference between the K-510-sized horn and the K-402-sized horn using only a compression driver?  YES, you certainly can.  Which one sounds better?  No one I know has ever picked a K-510 over a K-402 in terms of the sound.  The K-402 wins hands down.

 

That room size you describe is a nice size.  Your proposed MEH horn sizes will work quite well in that space.

 

On 12/2/2020 at 5:35 AM, StabMe said:

However, ChrisA in his earlier posts on MEH says, if i understood him correctly, that A K-402 based MEH controls its polars down to 100Hz when placed into the corners. Am i going to achieve this with the approach i mention? 

 

The reason for the K-402-MEH design (full-range) is because it avoids the midbass and/or midrange polar disruption problems of other loudspeakers, and is the calling card for this particular type of MEH (like the Danley SH-50, SH-60 and SH-96, but at 1/5th to 1/10th the price if you DIY).  The K-402-MEH-sized horn brings the frequency at which you lose polar control down to below the Schroeder frequency of the room (nominally this is about 200 Hz).

 

The reason why the Schroeder frequency is important is if you can get the horn's mouth size to control its polars below that frequency, then the room no longer behaves like an optical reflection problem, but rather a standing-wave problem, and therefore loss of polar control no longer is perceived as a loss of polar control by the human hearing system.  The K-402 begins to lose its horizontal directivity at 170 Hz (as you can see from the K-402-MEH thread in the first posting), and finished the polar wrap-around point at ~100 Hz.  Vertically, the K-402 horn begins to lose its vertical polar control at about 300 Hz, and loses it completely around 200 Hz.  So the size of the K-402's mouth (21 in/53.3cm vertical and 36"/91.5 cm horizontal) is about minimum in order to avoid loss of polar directivity above the room's Schroeder frequency. 

 

You are proposing a slightly larger size horn, which will also control its horizontal polars down to 100 Hz (mid-wall mounted) and 200 Hz in the vertical axis, and therefore avoid the need for a separate bass bin.

 

On 12/2/2020 at 5:35 AM, StabMe said:

Or, if i am after a speaker system that controls its directivity and provides horn loading down to 100Hz, i should better choose another 2-way system with a separate bass bin (La Scala, FH-1 or Khorn)?

I personally see no advantage to using a separate bass bin.  For the size of an additional 15" woofer in the MEH, you get much better overall performance including much more consistent polar coverage and absence of lobing down to a very low frequency--below that of the La Scala or Belle, and even giving the Khorn and Jubilee bass bins a run for their money.  The reason why I can say this is because these bass bins are exponential in their expansion, and as such have a definite cut-off frequency (f₃), while the K-402 or a dual-taper horn like you're proposing will have a more gentle low frequency roll-off curve--like the difference between an acoustic suspension bass bin and a reflex ported box (the reflex box rolls off much more dramatically than the acoustic suspension below it's resonance frequency). 

 

More information that explains this effect here (click the top line link to take you the exact posting):

 

 

On 12/2/2020 at 5:35 AM, StabMe said:

P.S. Forgive my ignorance if i am asking stupid things.

Nothing stupid in your questions.  Very good ones.

 

Chris