The Great Waveguide Shootout

Objective Tests of Various Horns and Waveguides

This project was started almost 7 years ago on AVS forum and then nearly abandoned for just as long. The idea was to test and provide various measurements on a wide range of waveguide and horn designs making it easier to understand the relative performance of each.

Initially I will focus on the directivity control of the various waveguides providing on/off axis frequency response, normalized plots and polar sonograms for the vertical and horizontal axis. Measurements may be expanded to Sensitivity and Distortion comparisons in the future and/or I may add some compression driver comparisons/tests as well.

There will be a lot to measure so the tests and data will likely come in and be uploaded here slowly. Updates when more data has been added will likely be posted to the original forum thread. Link to that here in case you missed it above.

The Original Test Rig

The initial project hit a snag early on with the initial testing rig providing troublesome measurement data, reflections from the rotating mic boom & baffle edge diffraction issues towards 90 degrees. It was also so large and cumbersome to setup that the whole idea was abandoned for several years. Recently I had an idea for a much simpler more compact test rig that is adjustable making it easier to mount and test waveguides of various shapes and sizes and so the project was restarted.

The New Test Rig

The new setup is a simple structure of 2020 aluminum that allows easy adjustment the width of the rig to conform to the waveguide being tested (no longer the need to make baffles for every waveguide). The smaller size and vertical orientation allows it to be used indoors which is a huge plus as measurements can be taken easily without waiting for the weather to be cooperative.

I made large roundovers out of cut down sonotube mounted to the sides and covered in egg-crate foam in order to minimize reflections and edge diffraction. Though it is evolving as the modular nature makes it easy to change out sections as needed. So far the measurements are clean without any noticeable diffraction ripples out to 90 degrees which is what I was shooting for.

As an added bonus I was able to design a small controller using an Arduino and stepper motor to remotely control the angle of the turntable in 5 degree steps. This will end up being a huge time saver not having to manually move the turntable during testing.

Update (4/7/2021):

Testing has paused as I noticed an issue with elevated 2nd harmonic distortion measurements from my UMIK-1. After ordering two new MiniDSP mics (another CSL Calibrated UMIK-1 and a new UMIK-2 from MiniDSP) I've found they all have issues with elevated 2nd harmonic distortion generated from either the capsule or built in preamp at SPL levels well below their rating (seeing a rise at SPL levels as low as 90dB) making them unsuitable for distortion testing.

My older UMM-6 does not exhibit this same behavior and I was able to create a new calibration file for it testing it against one of the CSL calibrated UMIK-1's so the waveguide measurements may resume soon using that mic.

In the mean time I have removed all the distortion measurements as they are inaccurate.


Update (October-2021):

Expecting to resume measurements in the coming months, my new Earthworks M23 will be used for testing which does not suffer from distortion issues at high SPL.

Loads more waveguides/horns and compression drivers have been acquired. I'll focus on directivity/polars of the various waveguides first then testing of the compression drivers on the more popular waveguides.

Horn and Waveguide Tests:



1 Inch - 1-3/8"-18 TPI (Threaded):





1 Inch - Bolt On:











1.4" - Bolt On:









Compression Driver Tests:

1 Inch - 1-3/8"-18 TPI (Threaded):

Eminence F110M-8

1" Voice Coil

Mylar Diaphragm

Ferrite Magnet

Eminence ASD1001

1.3" Voice Coil

Titanium Diaphragm

Ferrite Magnet

Celestion CDX1-1010

1" Voice Coil

PETP Diaphragm

Ferrite Magnet

Celestion CDX1-1446

1.4" Voice Coil

PETP Diaphragm

Ferrite Magnet

Celestion CDX1-1731

1.75" Voice Coil

PETP Diaphragm

Neodymium Magnet

PRV DH175Ph-S

1" Voice Coil

Phenolic Diaphragm

Ferrite Magnet

PRV D230Ti-S

1.4" Voice Coil

Titanium Diaphragm

Ferrite Magnet

PRV D280Ti-S

1.75" Voice Coil

Titanium Diaphragm

Ferrite Magnet

Timpano TPT-DH175

1" Voice Coil

Phenolic Diaphragm

Ferrite Magnet

Timpano TPT-D250X

2" Voice Coil

Phenolic Diaphragm

Ferrite Magnet

Denovo DNA-150

1" Voice Coil

Phenolic Diaphragm

Neodymium Magnet

Blast King 72BHM200PL

1.4" Voice Coil

Titanium Diaphragm

Ferrite Magnet

1 Inch - Bolt On:







1.4" - Bolt On:

Eminence N314X-8

3" Voice Coil

TeXtreme ® Diaphragm

Neodymium Magnet

More tests coming soon!