Product: TNT Sonus Flatter - DIY speakers cable
Manufacturer: TNT-Audio DIY design - NOT for sale!
Approx. cost: variable, depending on configuration, starting as low as 0.5 $/meter
Application: HiFi, Home Theater and car audio systems
Required tools: a pair of scissors and, eventually, a wire stripper. Soldering gun NOT REQUIRED.
Designer: Lucio Cadeddu
Published: June, 2001

We at TNT-Audio always try to satisfy every audiophile's need, offering free DIY designs that should be inexpensive and easy to build. For this reason, as speaker cables, we dare to propose different designs, from the simplest TNT Star, entry-level design for novices, till the most complicated TNT FFRC, TNT Triple T and TNT U-Byte.
These designs, though not hard to build, require a good amount of patience, self-control and DIYing skills and, sometimes, the bare cables needed to build them aren't commonly available in custom lenghts. Sometimes one is forced to buy a reel of 25 meters and build cables for the rest of his life :-)
Furthermore, these cables are obtrusive, hence not welcomed into elegant living rooms.

For these reasons I've decided to recycle an old commercial hi-end cable design that dates back to the mid-Eighties, the Straight Wire Music Ribbon, and propose a poorer DIY version, at a fraction of the original cost.

So, let's state this clear before we start: this idea is NOT new and, besides the Straight Wire Music Ribbon, other audiophiles around the World may have thought (or actually built) a speakers cable similar to this one I'm going to describe here.
Hence, please avoid ridiculous E-mails claiming you have been using a similar design in the early Fifties...nothing's really new under the Sun.

I wanted a cable: 1) easy to build (easier than our previous DIY designs), 2) damn cheap and 3) living-room friendly. A FLAT cable, that is. Something you can easily hide below carpets, for example, in Home Theater applications.
Hence, lads and gentlemen, here is the TNT Sonus Flatter! No, not a serious contender for our FFRC, Triple T or U-Byte cables, still a decent cable able to rival with our basic design, the TNT Star.
Compared with the TNT Star, the TNT Sonus Flatter is easier to build and the bare cable needed to build it is FAR easier to find.
Why Sonus Flatter?, you may ask. Well, first of all because it is FLAT :-), then because it reminds some glorious name in HiFi (hence it is easy to remember :-)) and finally because it flattens the sound (no, just kidding). No way, dudes, you'll be flattered!!! :-)

Required stuff

You can't complain! The cable needed to build this DIY speakers cable is EASY to find because you just need to pay a visit to any computer or electronics parts store!!! You just need to ask for hard disk multi-way flat cable or gray ribbon cable (or show the salesman the picture above, pics speak so much louder than words :-)).
If possible, buy the 64 way version though any other flat cable with an even number of conductors will work just fine. Cost: starting from 0.5$/Euro per meter depending on quantity, number of ways and salesman's audiophileness ;-)
A pair of scissors or, better, a wire stripper, may help getting the job done quickly. Wire strippers are easily available at any bricolage and DIY store for 5 $ or so (and it is a tool you may use several times). If in doubt, search the RS catalogue using "wire strippers" as keyword.

Though not strictly necessary, here is some tech spec taken from the RS catalogue for the "ribbon cable". If you want, you can search again the RS catalogue online at www.rswww.com using "grey ribbon cables" as keyword.
Have in mind the cable is often referred to have the universal code To UL 2651

• Tinned copper stranded cables with PVC insulation.
• Each way consists of 7 strands - 36 AWG (0.13 mm) - 28 AWG overall (0,08 mm2).
• Nominal impedance: 105 Ohm
• Capacity (between near conductors): 49 pF/meter
• Nominal voltage: 300V
• Width (64 ways version): 8 cm (3")

Building the Sonus Flatter!

This hard-disk flat cable is sold in custom lenghts so you don't need to buy a reel of 25 meters to build a pair of 3 + 3 meters cables. So, if you normally use a 3 + 3 pair of speaker cables, buy 3,5 + 3,5 meters (that is, 7 meters :-)) of ribbon cable.
In other words, you should always buy the cable slightly longer than needed. Building mistakes are going to fool you, so it is better to have some extra cable left :-)
Now, consider a 64 ways cable will let you build a stereo pair with 32 ways each, 4 pairs with 16 ways each and so on. Also, consider the 64 pole cable is 8 cms large, the 32 pole is 4 cms large and so on. I've built and tested ANY (I mean, ANY!!) configuration: 64, 32, 16 and 8 ways.
A good compromise between sound and "size" is the 32 ways configuration (let's call it Sonus Flatter 32) and the 16 ways one isn't all that bad (read my listening impressions below).
If you want to build a (double) 3 + 3 meters pair of Sonus Flatter 32 you just need 7 meters of 64 ways ribbon cable. Cut it into two pieces of 3.5 meters each and then divide these in half, so to get a double stereo pair consisting of 32 ways each. Even if you do not use biwiring, the second pair may be useful for experiments, in case you make some irreparable mistake when building the first pair. Otherwise, you may decide to build a SINGLE pair of Sonus Flatter 64.

And now for the unnerving part: you have 32 x 4 (= 128!!!) conductors to strip. Before you start, an useful advice: separate each conductor from the other for 5 cms at least (2 inches). Now that each conductor is "single", strip the PVC insulation for 2.5 cms (1") at least.
Be extremely careful as these conductors are very thin and prone to break easily if you apply too much force. Take all the time you need and remember that if you break a conductor you need to start again.
He who "cares" wins!!!! :-)

Now that you have 32 bare conductors you need to connect them in order to get a standard 2 pole (positive and negative) speaker cable. The conductors must been connected alternatively, that is to say: the first with the third, with the fifth etc. Hence, 16 conductors will be the "positive" pole (mark it - AT BOTH SIDES OF THE CABLE - with a red marker or adhesive tape) the other 16 will be the "negative" pole. There's just one thing you should take care of: the conductors you choose as positive pole at one side should be THE SAME at the other side of the cable. This sounds stupidly obvious, but if the cable is very long, it is easy to make a mistake.
Now apply the same procedure to the other cable and your TNT Sonus Flatter is ready to.... flatter you! Have a look at the pictures to see how the cable should look like when all the work is done and your fingers are sore.
Consider that, for cleaner looks, the picture refers to a Sonus Flatter 16 (8 conductors per pole).
Now, before you hook up the cable to your amp and loudspeakers, you MUST...

Try this!!!

It is quite easy to make mistakes (though I got it right the first time :-)) and these can be very dangerous for your system, especially for your amp's health. So you need to be SURE the cable works properly.
Take a 1.5 volts battery and a low-voltage light bulb (from an old bicycle or a torch) and connect these using your Sonus Flatter cable. If you see the light :-) then the cable is OK. Otherwise you should double-check the pairings you made.

WARNING. If the cables you have built don't work this way (provided the battery and the bulb are OK ;-) ), DO NOT CONNECT THEM to your system!!!! Also, DO NOT PERFORM this test with higher voltage batteries or, even worse, with the mains. Electricity kills.
If you're not sure of the result, DO NOT CONNECT the cables to anything and have them checked by a trained electrician.
TNT-Audio has no responsability for damages or injuries caused by a wrongly built or connected Sonus Flatter cable.

Does it flatten the sound? :-) or will it flatter you?

Well, the Sonus Flatter hasn't been designed to rival with our better DIY cables so I just wanted it to be (even) slightly better than (or close to) our basic TNT Star.
I've listened to any possible configuration and here are my findings: the Sonus Flatter 64 (32 conductors per pole) is quite an interesting design, though being pretty wide (8 cms) it fails to be easily hidden (it stills works fine under carpets!). The Sonus Flatter 32 is the best compromise: easy to hide and good sounding.
The mid-high range is definitely smoother and more refined than with the TNT Star. The bass range is very close. To do better, you need the Sonus Flatter 64.
The Sonus Flatter 16 is VERY easy to hide though its sound is only slightly better than the ubiquitous figure-8 multistranded cable. Forget the minimalist Sonus Flatter 8 as it fails to deliver an acceptable HiFi sound. It may be successfully used to feed small rear speakers in a Dolby ProLogic environment (NOT Dolby Digital!).

And now two words about the Sonus Flatter 64. As many of you techno-minded may have already guessed, this kind of "alternative pairing" makes the Sonus Flatter a high-capacitance cable.
For example, a standard Sonus Flatter 64 easily exceeds 5,000 (yes, 5,000!!) pF. This means some amplifier could not appreciate it much. Certainly you can't use it with Naim, NVA amplifiers or similar designs known to have problems with high-capacity loads (actually Naim suggests to AVOID special cables and recommends their NACA).
The Sonus Flatter 32 is an easier load and the Sonus Flatter 16 should be welcomed by ANY amplifier made on Earth. For this reason you should use the 64 version only with strong and stable amps, while the other versions can be used almost with anything.
Since any amplifier reacts differently to capacitive load it is even hard to predict the kind of sound it will deliver when conneced to your speakers. The capacitive load "seen" by the amp also depends (strongly) by the kind of crossover network your speakers use.

Some further advice

If you're planning to use a double run of Sonus Flatter, i.e. in biwiring mode, please consider this will double the capacitance. A biwring made with a double run of Sonus Flatter 32 equals to a single run of Sonus Flatter 64.

There are several (dozens, actually) models of ribbon cables, I've used the most commonly available and, certainly, the cheapest one. Considering the results I got, I doubt further experiments with more sophisticated ribbons are worth the hassle.
Anyway, if you want to try, please send us your findings and comments. For example, there's a kind of ribbon cable where the conductors are shielded. It may be worth considering. Forget using this for interconnects, as capacitance would be way too high.
If you want to try, don't ask us to predict the results.
We lost our superhuman and paranormal powers hundreds years ago :-)

Before you ask: use the terminations you prefer. Bananas, forks or even bare wire should work fine. If you want, you can solder the conductors for a safer contact (sometimes it is hard to keep all the strands together).

These cables are meant to be hidden under carpets or so, please have in mind the actual WIDTH of the cable before building it.
In my opinion, the Sonus Flatter 32 is the best compromise.

Conclusions

The TNT Sonus Flatter has been designed having simplicity and low cost in mind, so it is NO hi-end stuff.
If you need to hide your cables and/or your Home Theater installation requires long runs of these, commercial cables may be expensive. Hence, give this design a try before shelling out your hard earned cash. Perhaps not the ultimate in sound quality, certainly one of the cheapest & simplest cables around.
Die-hard audiophiles with die-harder amplifiers may want to try the maximus configuration, i.e. the Sonus Flatter 64. It may be an interesting and...dare I say it...flattering experience.

Happy DIYing to everyone!

© Copyright 2001 Lucio Cadeddu - http://www.tnt-audio.com