Three ways active columns Athom Dynaudio Digmoda - Home Theater Forum and Systems -

Thread Tools
post #1 of 6 Old 11-20-12, 05:33 AM Thread Starter
Join Date: Nov 2011
Location: Brussels
Posts: 9
Three ways active columns Athom Dynaudio Digmoda

A few months ago, I made two three ways active Columns comprising each: one Atohm D300-P04 for the low frequencies, two Dynaudio 20W75 8 Ohms for medium freq and one Dynaudio D260 for highs. The enclosure is filtered and amplified by Digmoda DDC552.

The project was born from the will to transform my existing columns in order to have more bass. I like Rock and Pop, also Dance music so basses are paramount.
They were each made of one Dynaudio 20W75 8 Ohms and one D260 with a 2nd order filter created by a store selling kits that no longer exists.

The sensitivity of the tweeter being of about 5dB higher than that of woofer, I wanted to create a system MTM (appolito) and to increase by there the sensitivity of the woofers by 3dB. The modification of the filter would have been rather easy because it is approximately enough to double the components and to change the value of the resistance in serie with the tweeter. Ebay allowed me to find a new pair of woofers that Dynaudio does not market any more as parts.

Mr. Petoin Dominique (whom I thank here for his answers to my e-mails) and his site (in french) made me realize that if I wanted to go down low in frequency, I would quickly be limited by the excursion of the membrane of the 20W75.
I thus needed a third way dedicated to the basses.

The filtering of one three ways being a difficult enterprise, I decided to actively amplify all these beautiful people and my choice was made on a Digmoda DDC552 (ordered directly at Digmoda) whose characteristics of power matches perfectly the loudspeakers.
It is also equipped with an active filter + EQ that can be configured using a PC, a USB cable an the included D-PRO software.
Dean from Digmoda confirmed this choice and I thank him for all his advises and answers to my mails.

It was necessary to put all this small world in a box and I decided to manufacture broad columns with front mounted drivers.
For the basses, I kept same volume and the same vents as those of the Rafale sub-woofer kit from Atohm but I wanted a front-ported cabinet (the kit is rear-ported).
For mids and highs, I needed a much smaller volume, closed this time.
With a trapezoidal form for the sides , it was relatively easy to make a single cabinet,
the Digmoda amp fitting perfectly at the back.

Using the Digmoda, it was easy to make a three way filter and adjust output levels. I only used 2nd order filters.
I tried to flatten the bass response curve using the EQ capabilities but I finally decided to make no correction as the sound was much better uncorrected (I am just an amateur !).
I tweaked the filters a little bit and the sound is great!

I have what I wanted when I started this project: more basses! The rest of the spectrum is as it used to be and I have always been happy with it.
The difference now is that the music really makes me willing to dance.
Even at low volume, basses are felt and give music more presence.

Some pictures later on when I am allowed by the site...

In the meantime, if someone could send me a link to a page explaining how to measure and time-align the speakers, I would be thankful as I could not find two persons agreeing on the method (time or phase alignment, use the peak, use the threshold, etc...)
Himmelman is offline  
Sponsored Links
post #2 of 6 Old 11-20-12, 06:10 AM Thread Starter
Join Date: Nov 2011
Location: Brussels
Posts: 9
Re: Three ways active columns Athom Dynaudio Digmoda

As promised, some pictures:
(Legend on top)

Outboard: the 2 ways speakers I wanted to upgrade.
Inboard: the front plates of the new 3 ways speakers. Ouch! no very WAF

Uploaded with

A look inside....

Uploaded with

The new 3 ways next to the previous 2 ways speaker.

Uploaded with

Uploaded with

And finished
Front face is painted, the rest is veneered with real oak coated with white glue diluted in water

Uploaded with

Uploaded with

Uploaded with

Last edited by Himmelman; 12-06-12 at 10:40 AM. Reason: image integration
Himmelman is offline  
post #3 of 6 Old 11-20-12, 06:35 AM
Elite Shackster
Wardsweb's Avatar
Join Date: Apr 2010
Location: San Antonio, TX
Posts: 1,752
My System
Re: Three ways active columns Athom Dynaudio Digmoda

Very nice build. What software are you using for your measurements?

~There are many roads to nirvana, while the ultimate goal is the destination, don't forget to enjoy the ride~
Wardsweb is offline  
post #4 of 6 Old 11-20-12, 08:06 AM Thread Starter
Join Date: Nov 2011
Location: Brussels
Posts: 9
Re: Three ways active columns Athom Dynaudio Digmoda

For measurements, I used REW mainly, HOLMImpulse as well.
Himmelman is offline  
post #5 of 6 Old 12-06-12, 10:24 AM Thread Starter
Join Date: Nov 2011
Location: Brussels
Posts: 9
Re: Three ways active columns Athom Dynaudio Digmoda

- It is better to make measurements at the listening position rather than a meter away
- one need a downward curve in the treble region (curve X ISO 2669, academy mono, B & K house curve, choose what suits you ...)
I performed the following measures (1/3 octave smoothing) in the axis at a distance of 2.6m after some equalization work above 200 Hz

I used REW in automatic mode between 200 and 2000 Hz for a flat response and in manual mode beyond 2000 Hz for the curve (which descends naturally) to be straight.
The calculated data have been copied manually into the D-Pro software supplied with the Digmoda amps and transmitted them via USB from the PC to the speakers (easy!).

We notice that the right speaker placed near a corner gives more level in the low frequencies (blue curve) and a slight depression between 200 and 300 Hz that I have not tried to correct.

Uploaded with
Himmelman is offline  
post #6 of 6 Old 12-06-12, 01:29 PM
HTS Senior Moderator
robbo266317's Avatar
Join Date: Sep 2008
Location: Newcastle Australia
Posts: 5,624
Re: Three ways active columns Athom Dynaudio Digmoda

They are nice looking speakers. Well done!

Silence is golden but duct tape is silver.

DIY completed:
robbo266317 is offline  


active , athom , columns , digmoda , dynaudio , ways

Quick Reply

Register Now



Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address



Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.


See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


For the best viewing experience please update your browser to Google Chrome