Monacor Direct HA Edition with SPH-176, MSH-116 / 4 and DT-25N

Development Report Monacor Direct HA Edition Part 1 (The Original Direct) Test & metrological documentation of the center speaker Monacor Direct

Metrological documentation of the center speaker Monacor Direct. The findings obtained during the investigation of the original Direct ultimately led to the development of the Monacor Direct HA Edition.

Development Report Monacor Direct Heißmann-Acoustics Edition

PART 1: The original Monacor Direct

 (to the 2 part: Monacor Direct HA Edition)

Monacor Direct HA Edition with SPH-176, MSH-116 / 4 and DT-25N


Monacor Direct is a horizontal center speaker, equipped with reasonably reasonable chassis. The woofers are two SPH-176, Midrange is the MSH 116 and in the treble, the neodymium calotte works DT 25N, When I got a customer request, if I could deliver the kit and if I would find it useful to realize a home theater equipped with 5 this speaker, my answer was the following:

Assembly and arrangement promise a very good speaker, which could act as a high-quality center but also as a main and rear speakers. In order to be able to judge this conclusively, I first have to analyze the switch further

Since I had already recorded the installed chassis metrologically, I was able to create an initially rough simulation, which brought me to the conclusion that I can not recommend this kit so. Neither as a center nor as a main, - or Rearlautsprecher!


The great potential of Monacor Direct is that, contrary to "normal" center constructions in a lying d´appolito arrangement, it can / could achieve a balanced horizontal omnidirectional pattern. In order to achieve this goal, however, one of the things needed is sufficiently deep separation between woofer and midrange, My simulation told me that the separation between SPH-176 and MSH-116 was a bit, let's say, unusual, with the result being a very unbalanced horizontal omnidirectional behavior.

I explained this fact to the customer, and soon we agreed on a new development of Monacor Direct.

The first step for me was to build up the original Direct to substantiate my identified doubts.

Below are the measurements of the original Direct:

Monacor Direct branches and sum 0 °


(blue: Monacor SPH-176, green: Monacor MSH-116, red: Monacor DT-25N)
  • The Monacor MSH-116 plays up to -10dB characteristic sound pressure. This he reaches at about 1750Hz. Above and below it says goodbye with about 6dB / octave
  • There is no real separation from the SPH-176.
  • The falling edges of MSH-116 and SPH-176 are nearly parallel
  • Monacor SPH-176 and Monacor DT-25N look more like a classic 17 / 25 2-way speaker
  • Monacor DT-25 plays very low. Too deep in my opinion. In the following diagram you can see that the DT-25N would cope with such a deep separation, purely from the point of view of the distortion values, but its resonance frequency of 1500Hz clearly speaks for a steep-edged separation> 2000Hz

Harmonic distortions Monacor DT-25N sonicated in the kit Direct

 Monacor DT25N distortion sonicated


For fun I disconnected the MSH-116 and measured it ...

Monacor Direct without MSH-116

Monacor Direct SZV without MT

This looks noticeably similar to the following ...

Monacor_Direct_Hersteller Source: Monacor online catalog “Loudspeaker DIY Now” page 96


 Monacor Direct Impedance

Monacor Direct Impedance

And finally:

Monacor Direct Frequency Response at Angles (0 °, 15 °, 30 °, 45 °, 60 °)

Monacor DT25N angle measurements(black: 0 °, red: 15 °, blue: 30 °, green: 45 °, brown: 60 °)


Up to 15 ° good, above that according to the faulty concept of all lying quasi d´appolito 2-way constructions. Unbalanced at angles> 15 ° with massive drops from> = 30 ° ..

And finally ...

Monacor Direct can not be called a classic 3-way speaker. Technically, it is more a lying 2-way quasi d'appollito center (with filler driver sU). The interpretation of the question of what the MSH-116 was installed at all, I leave you * (I think I have just decided to Duzen in the magazine). What this documentation should also show is that the publication of a frequency response on the axis is still very little about the speaker able to testify.

The Center Monacor Direct has a lot more potential than the one offered.

Therefore it becomes one Hot man Acoustics Edition give this speaker. The turnout development is largely complete ... More on that soon in the 2.TEIL this report.


* Then I was taken at my word, and got an interpretation:

I was made aware by a user in the Diy-Hifi-Forum that the type of wiring of the MSH-116 is called "Filler-Driver" in the original Direct. The concept of the filler driver was first presented in the "Journal Of The Audio Engineering Society" in 1977. The purpose is to eliminate phase problems from Linkwitz and Butterworth filters.

The basic problem of Direct remains despite the well-known name of the filtering ... the horizontal omnidirectional behavior. I will also continue to say that the MSH-116 is a very, very good midrange driver that should be played with a broadband if possible.

But you never stop learning, and I am grateful when I am made aware of gaps and mistakes ...

to the 2. Part, the development report for the Monacor Direct HA edition

2 thoughts too "Development Report Monacor Direct HA Edition Part 1 (The Original Direct) Test & metrological documentation of the center speaker Monacor Direct"

  1. I'm the customer and I'm looking forward to the loudspeaker. In terms of the concept, I found the Direct to be ideal, it is nice that every Chassís now has its own work area.

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