Ndarfield Computer MTMPR

Ndarfield Computer MTMPR



Project Category:
Bookshelf Speakers

Project Level


Project Time:

8-20 Hours

Project Cost:


Project Description:

I had modded my previous set of computer monitors with a better tweeter and custom crossover. Eventually I decided it wasn’t enough and I got the bug to start from scratch. I have always been enamored of MTM speaker projects and I thought it would be great to do a mini MTM for my computer!

Design Goals:
I wanted the drivers to match as seemlessly as possible within the space restrictions I had laid out. because of the drivers used I would have had a ridiculously long port, so I decide to go with a passive radiator. I built the executive boombox so I’m familiar with them. Without frequency modeling software, I decided to go with an assembled xover.

Driver Selection:

I chose the Dayton PC83-4 3.5″ full range. Since this is an MTM with a Morel MDT12 for the tweeter, I bought the 4 ohm version of the Daytons. These were wired in series to give an 8 ohm load. I chose the Dayton DS175-PR to help get the response lower.

Enclosure Design

I had 10 inches as a width to work with. These were going to be deeper than normal to accommodate the 6.5″ passive radiator. Ended up being about 9 inches deep and 5″ tall. I used 3/4 MDF.

Crossover Design:

Since the Dayton PC83-4 are full range, I decided to go with a higher xover point to relieve some of the stress off the Morels. I chose 4.5k. I really didn’t feel like doing a custom xover without hearing the assembled xover first. I can always go back later and spend another $150 on custom parts!

Tips & Tricks:

I didn’t use anything but glue and clamps. Not a lot of air pressure from the drivers so I didn’t use anything stronger.


I am really ecstatic with how these sound. When these break in, I believe they will really open up. The Morels offer crystaline highs and open vocals. The Daytons are the real surprise here. So much better than I expected. With the passive radiator these little things are beasts! Can’t wait to they really break in.

About the Designer:
Been tinkering all my life. Built a few MTMs. Currently have more speakers and design ideas than I can keep up with (much to my wife’s chagrin!).

Project Parts List:

Part #DescriptionQty.
295-154Dayton Audio PC83-4 Full Range Speaker4
277-060Morel MDT12 Tweeter2
295-498Dayton Audio DS175-PR 6-1/2″ Designer Series Passive
260-148Dayton Audio XO2W-4.5K Assembled Crossover2
260-276Parts Express Round Speaker Wire Terminal Cup 2-15/16″ Gold
N/AKrylon Gloss Black spray paint.1
N/AGorilla Glue Clear1

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