• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

My DIY Zaph Audio ZRT speaker build

Feanor

Active Member
Forum Donor
Joined
Feb 22, 2019
Messages
277
Likes
229
Location
southwestern Ontario
#1
For the heck of it a couple of year back I decide that I wanted to build a pair of DIY speakers. I had a couple of goals:
  • The new speakers must capable of high quality sound, and
  • They must be less imposing than my then current Magneplanar MG 1.6QR panel speakers
Before and After the new speakers
...
1600891635833.png

1600891708986.png


The hunt was then on for a suitable speaker design.

I had previously done a couple my own speaker designs using Harris Tech's Crossover Pro and Bass Box Pro software that turned out OK. But given my goal of high-quality I decided for a a design by an expert. After much searching looking kits at Madison, Meniscus, Parts Express, etc., I decided on Zaph Audio's ZRT 'Zaph Revelator Towers'. See ... http://www.zaphaudio.com/ZRT.htmlr

The ZRT's are small towers utilizing high quality Scan-Speak drivers, namely:
  • Illuminator D3004/6600 AirCirc Tweeter Textile Dome, and
  • ScanSpeak Revelator 18W/8531G-00 7" Mid Woofer 8 ohm
I selected the 2-way vented alternative versu the 2.5-way closed box because I deemed it would yield enough bass and better suited my budget.

The specs looked good. The frequency response and distortion graphs per the Zaph Audio look like this ...
On-axis measured response:
1600891787647.png


Measured far-field harmonic distortion:
1600891817532.png
f

The drivers and completed crossovers were (and are) available from Madisound. I selected the Goertz 14 ga. copper foil inductors upgrade. ...
https://www.madisoundspeakerstore.com/2-way-speaker-kits/zaph|audio-zrt-2-way-revelator-tower-parts-only-pair/

Zaph Audio designed the ZRT's for Madison's MD38T tower speaker enclosure, 1.33 cu.ft. However this enclosure is no longer available. Since I don't have access to a table saw, I looked for a close pre-fab alternative. This turned out to be Parts Express' Denovo Audio Knock-Down MDF 1.16 cu. ft. Tower Cabinet. Since this cabinet is a little smaller than the originally intended 1.33 cu.ft., I used Bass Box Pro to calculated a different vent length for the smaller volume. I glued an extra 1/4" of MDF to the front of the baffle to make it a full 1" thick.

Since fine cabinet finishing isn't one of my talents, I decided to use a simple painted finish on the MDF. I used a latex flat finish paint and dress the surface with carnauba automobile wax. I fabricated the black cabinet bases myself ...

1600891915336.png


These nearly finished pictures don't show the Part Express Acousta-Stuf Polyfill used to moderately pack the lowest section of each cabinet.

I don't have the equipment to properly test the final result, but it sounds great to me. The ZRT's are more transparent than the Maggies and have slightly better articulated bass ...
1600891993766.png
 
Last edited:
OP
Feanor

Feanor

Active Member
Forum Donor
Joined
Feb 22, 2019
Messages
277
Likes
229
Location
southwestern Ontario
Thread Starter #3

gfinlays

New Member
Joined
May 30, 2020
Messages
3
Likes
3
#5
I've recently built the 20 litre sealed version of this speaker using a baltic birch plywood cabinet to the same dimensions as the no-longer available MD20. Driver integration is superb, sound is very detailed with no harshness, bass is more than adequate and the soundstage is wide and deep. I'm very, very happy with them.
 
OP
Feanor

Feanor

Active Member
Forum Donor
Joined
Feb 22, 2019
Messages
277
Likes
229
Location
southwestern Ontario
Thread Starter #6
I've recently built the 20 litre sealed version of this speaker using a baltic birch plywood cabinet to the same dimensions as the no-longer available MD20. Driver integration is superb, sound is very detailed with no harshness, bass is more than adequate and the soundstage is wide and deep. I'm very, very happy with them.
I'm certainly very happy with my ZRT. I don't think using the slightly small box was a problem.

I'd love to see Amir test the ZRT but it certainly isn't practical for me to ship him a speaker.
 

tmtomh

Addicted to Fun and Learning
Joined
Aug 14, 2018
Messages
506
Likes
1,179
#7
Very cool - thank you for sharing @Feanor! Also great to see that even without access to a full suite of woodworking tools one can assemble a very nice pair of DIY speakers.
 

gfinlays

New Member
Joined
May 30, 2020
Messages
3
Likes
3
#8
I'm certainly very happy with my ZRT. I don't think using the slightly small box was a problem.

I'd love to see Amir test the ZRT but it certainly isn't practical for me to ship him a speaker.
Indeed, there were some rumours around a few years back (closely linked to the designer of the 18W8531) that seemed to suggest it was designed for a 22 litre cabinet.

I'm in the UK, so shipping one of mine isn't really practical either......
 
Top Bottom