Madisound Vifa Studio DIY Monitor

[jksuperstar]

Madisound Vifa Studio Kit

by jksuperstar – Justin Koller

Being an avid “I can try to do it better myself!” kind of guy, rather than shovel out a few hundred dollars for something I know costs 1/5th to make, I thought I'd try my hand at build my own studio monitors, not from scratch, but based on a kit. I've built home speakers, as well as designed them for others in the past, and know very well that loudspeaker design is a delicate art. It requires a fair set of tools to do the complete job right, not to mention the experience it takes to design a crossover that doesn't destroy phase information in the crucial band of frequencies that are emanating from both woofer and tweeter. Since this set of loudspeakers would be my reference studio monitors, I thought it better to start from a kit rather than from scratch.

Two primary companies I searched through for kits were Madisound and Parts Express. Both provide kits for various levels and budgets, and both have delivered kits that are well received by audiophiles and college students alike. The quality of components used is bar none, since these two companies primarily serve as distributors for high-end drivers and cross-over components. After much reading (reviews, comments, and suppositions), I was settling on the Madisound Vifa Studio, a kit that uses a now “famous” tweeter and smaller (5.8”) woofers, which I like since I feel they are more accurate at presenting details in music, though they might not be the best for bass extension like an 8” driver would be. This kit also added a 6.5” passive radiator, that extended the bass down below 50Hz! Passive radiators aren't as popular as ported enclosures are, since they cost more, but can be found in designs like the Mackie 824, and in home theater speakers by Polk. I decided to seek out a few professional speakers that used the components in the kits I looked at. Ultimately, I found a set of Blue Sky Sat 6.5 speakers at Guitar Center that applied the same tweeter as in the Vifa Studio, and was able to compare them to Event, Mackie, Yamaha, and other manufacturers in the same room, A/B/C style with the same source (two CD's I brought – Flim & The BB's (Tricycle), and Brian Eno and David Byrne (My Life in the Bush of Ghosts). The Blue Sky monitors, and they're tweeters, were very accurate and grabbed my attention immediately. This was the sound I was after, and was so excited by this experience as to commit myself to the Vifa Studio Kit from Madisound.

Part I – The Kit

The contents arrived in two boxes – one containing the pre-fabricated enclosures, the other all the various compnents. The cabinets are made of 1” MDF (Medium Density Fiber) on front and rear, with oak veneer over MDF used on the side panels. The boxes I ordered have a black finish, with grain visible on the sides, and the front & back have a matte finish over the MDF. They are also available in a clear oak finish, that maintains the black matte on front & back. They also come complete with dust covers, though I tend not to use them, since me studio is as dust-free as possible anyway, and they only tend to scatter sound, which isn't desirable for a near field monitor.

The components are all very high quality, with some of the drivers used in high quality manufacturers from the likes of Polk, Krell, and Audio Psychics in speakers ranging from $2k - $5k US each. The crossovers are well designed, using air-core inductors wound with 16awg wire (Madisound Sidewinder series) and large 10 watt, 5% Eagle resistors. This means the crossover is less likely to operate in a region of non-linearity, due to saturation and over heating. The tweeter is Vifa's latest dual-ring phase-plug design (XT25TG30), which has a large frequency range (allows the woofer to operate in a lower range), and very low-distortion. These features add to a clear & accurate image that doesn't tire the ear when listening for long periods of time. The 5.8” woofers (Vifa PL14WJ09) are augmented by Seas 6.5” passive radiators (H9944), which are one possible method of making a box of air look larger than it really is, while also shifting the boxes function from a spring reaction to a more damped reaction, like a shock-absorber on your car might do. This helps extend the bass frequency range of the box, while maintaining accurate bass recreation. Other methods of damping use tuned ports (those large holes & tubes that are present in many boxes). Some argue that the passive radiator is better since it prevents the possible noise from airflow that occurs inside tubes, but in today's designs tehse are rarely seen in well designed speakers, and you have to account for other faults of radiators, especially when mounted in the rear of the speaker like these are – they can't be placed right near a wall without having to consider the distortion that may be caused due to reflections (the sound eminating from the back will reflect off the wall and combine with the wave front causing a comb-filtering effect). So care needs to be taken when organizing your room and placing the monitors.

Part II – The Construction

The instructions to build the kit are clear and easy to follow. They require use of a hand drill (with 3/32” bit), soldering iron, and #2 Philips head screw driver. I found a knife or razor to also be helpful.

Step 1 – Drill pilot holes for the mounting screws for all drivers, and the terminating cup. Just place each driver in it's intended place, and use a small size (3/32”) bit so that mounting the screws is easier, and the wood won't split from the expansion of the screw. No driver can fit in the wrong hole here, so you really can't make a mistake. Just make sure you line things up according to how they will look, so you may want to place screws symetrically, or asymmetrically if you like.

Step 2 – Cut & strip wires to size (11”, 18”, and 22”), then pre-tin all connections, and solder to crossover only. The wire that's supplied is 16 awg wire, with bi-metallic conductors (one is aluminum, the other copper). I use aluminum to ground, and followed that consistently throughout. This helps keep your polarity correct, which is very important for the woofer & tweeter to work together rather than against each other in the cross-over range.

Step 3 – Clean out the box of debris (the dust from drilling), and mount the crossover using the pre-attached double-sided tape. Couldn't be any easier. Due to the size of the crossover, you can only slide it in one way, just give room around it for foam, the terminal cup, and the woofer, which all surround the crossover in the end.

Step 4 – Insert Foam sheets along wood panels (side, top, bottom). I haven't glued these in (yet), they seem to be cut for friction hold. They will reduce vibration/resonance of the box, and prevent standing waves along the inside surfaces of the box.

Step 5 – Apply foam tape sealer to all driver mounting areas. This tape acts like an air-barrier so that when the drivers are mounted, the box will be air tight, with no air to escape causing noise, and also reducing the efficiency of the box (much like a cracked clarinet would sound just horrible and out of tune).

Step 6 – Solder and mount the terminal cup. The solder provided has plenty of flux embedded in it, so it flows quite nicely on the brass leads that the terminal (and speakers) have. I had a fairly small-tipped iron, but it worked just fine.

Step 7 – fill the box 2/3 with AcoustaStuff, a synthetic wool replacement, which makes sound waves inside the box travel more slowly, thus making the box appear larger (acoustically) than it really is. It also helps disperse waves inside the box, and overall it's a very good idea to add this to any design. Adding or removing stuffing can help tune the box later on.

Step 8 – Add 12 grams of weight to the passive radiators. Each radiator has a screw protruding from the rear, that allows for metal washers to be mounted. Weight added to a cone reduces the resonant frequency, so the design of the radiators helps the monitor designer to tune the monitor based on the amount of weight added.


Step 9 – Solder and mount all drivers and passive radiators! Easy and the exciting conclusion to the construction!

All said & done, it took about 2.5hours to put these together, as seen below. In the final state, they each weight in at 14lbs, or 6kg. Fairly hefty for not having a built in amplifier.









Part III – The Break-in period

Most driver manufacturers recommend you “break in” all drivers before the final tuning of the monitor. This is accomplished by driving a white-noise signal to the speakers, exciting all frequencies and causing the drivers to move constantly, allowing for the surrounds and spiders (the parts that let the cone “float” with the voice coil) to properly stretch and settle. I've heard of some recommendations to set the levels, then reverse the polarity of one speaker, and face them at each other in close proximity...so you're white noise signal will be more or less canceled out, and you don't have to bear the many hours of white noise throughout your house! Setting the levels first is important, since the noise will largely cancel out, and it would be too easy to blow the drivers due to unknown high levels. Covering with a blanket in this setup is also recommended to reduce any stray sound. I simply closed the doors to my studio, and let them run while I left the house for the day. Levels and time are fairly subjective, but a full day at moderately high volumes (enough to move the woofer cones through most of their travel without distortion) should do it.

Part IV – Placement & Tuning

This is by the far the most most difficult, and subjective, part of the whole process. However, going through it teaches one a lot about the acoustics of rooms, and the effect of environment on speakers!

I'll be adding this part of the paper in the near future, watch for details!

[v-un-v]

What a lovely pair of speakers JK.

This article is fantastic too!

Don't you think that this would do better in the DIY forum where it would get more attention?

Tom

[KHashmi316]

I'm very much interested in this monitor as it is one of the ones I've been eyeing since its introduction.

Your intro was a very detailed and much appreciated. Any plans to update your review with listening tests soon?

Thx,
-KH