Slightly Portable Omnipolar Sound Quality Build

Welcome to my build.

I’ve been down the rabbit hole on sound for a while now. So I thought I’d share the latest evolution of my “portable” sound quality build.

I like found and re-used objects, so the build started some years ago with an old, somewhat character laden photographic flight case from a professional photographer. I was playing with an early version of the Up2Stream mini at the time streaming FLAC files to my kitchen system and seeing the case, it kind of all started. . .

The unit packed for transport.

Inside the Mirage Speakers and control tablet safely stowed.

I enjoy Mirage Speakers and the omnipolar sound they create (not for everyone, but I like it). I had rescued a pair of Omnisat v2 satellites from a garage sale, cosmetically mistreated but intact. Beautiful speakers with stunning power for about a pint in size, you can see where this is heading.

Their main limitation is base reach which trails off at 60-70hz. Well that won’t do, not for a sound quality focused system. Considering cabinet size of the flight case, the wish to transport the mirages inside for safety and the need for a subwoofer to fill the low end, a low profile pioneer car subwoofer was ideal for a sealed cabinet size.

And the unit setup and ready, I can place the Mirages out up to a meter each side for good stereo placement

During testing of the first (of many) iterations of the build I skilfully put 12volts and a truck load of amps through the Up2Stream Mini V1 I’d already had for a while. Seriously not recommended, and due to my stupidity, I did in fact let the magic blue smoke out and killed it. Not to worry, there had been a couple of updates and finally this build with a up2stream pro v3. In addition I’ve added the volume knob and improved DAC sub board and the aerial kit for external Wifi and Bluetooth (aluminium flight cases makes a surprisingly good faraday cage and measuring wifi range in inches ain’t good).

The system is mounted inside the lid of the Flight Case. Up2Strem Pro v3 lower centre, Dac Board above, voltage regulator to right with Li Ion Battery pack above, Amps to the left. and volume control board top centre

The Pro v3 drives two amps, both TPA 3116 based. The implementation of the boards makes a huge difference I’ve tried some awful 3116 boards - I’d suggest Aiyiam for sound quality they seem to do well with their implementations and i have had good results. I prefer the sound of the TPA 3255 amps but the risk at a party of someone getting keen and the speakers being overdriven isn’t worth it. I started with the red 2.1 amp (one of the better TPA3116 at the time) but now just use that for the stereo pair only ~50w a channel. The addition of the Aiyiam sub amp (100w) with a notably better and variable low pass filter brought the sub to life. I have been pleasantly surprised with the sub in the end. An important note – flight cases are nowhere near robust enough. The walls are very thin aluminium sheet and approx. 2mm ply. As you can see from this photo after much mucking about the solution for me was to line the existing walls with dynomat and then use a custom built 9mm MDF box to line the inside. With careful build and using a very slight taper, the box was friction fitted then the side walls driven in, slightly compressing the dynomat and making a very ridged enclosure. That combined with sorbothane D seals around the lid when compressed by the lid latches forms an air tight enclosure, that with the amp change, made all the difference. (I used the left over sorbothane seal around the base of the case to isolate the system from whatever its on ( stops is walking at high output and objects on the table buzzing).

Closeup of the reworked flight case, dynomat lines the inside of the original wall for deadening, with 9mm MDF box compressed against the dynomat for rigidity

Powered by a 21v lithium ion battery pack. (Mine is home built, but seriously not an area to experiment with, know what your doing, get it wrong and you’ll burn your house down – just buy a commercial pack, safer and much less grief). The next thing I learnt is that switch mode step down regulators suck. Taking the 21v to 5v to feed the up2stream has been a real source of noise. After a handful of different regulators and a range of filters, the no longer available, ifi usb filter was the best of the lot but expensive and not quite 100%. I’m now using a well regulated powerbank (not shown) which is silent. It’s a pain having another item to charge but unless someone can recommend a silent step down converter it’s in the end best answer I’ve found. The system runs at party level for 6hrs+ (haven’t yet quite got to the point of fully draining the battery)

The tablet is an old Nvidia shield, with a 256gb micro SD full of FLAC files, enough for my entire collection ~ 4,000 tracks. I typically use HiFi Cast to control the Up2Stream Pro v3 via DLNA. Arylic’s app is good and offers more control, but for random people at parties HiFi Cast seems more intuitive, they see the album art of something they know and we are good to go. I typically use my home server on the deck or backyard but can stream from the SD card in the tablet when out and about.

So how does it sound? Remember there has been about 4 years of iterations to get here, but wow. The Mirage V2s (these are much bigger than the much more common nanosat prestige) are really something. Fed clean power, FLAC files into the Up2Stream with the improved DAC board, good amps and you actually get that tingling down your spine you got the first time you tried high end headphones. From near field listening, through to party level, the sound quality is noticeable. I’ve had mates double take and come over to check out the system at parties from the sound alone. I hear detail and position like good headphones. My main system runs Mirage OMD-5s and the V2s rival them (but not the same low end).

Are there better systems? Certainly, but I wouldn’t be taking a $5k DAC outside or let acquaintances play with it at a party. That said its certainly in a different league to any Bluetooth speaker or portable stereo I’ve heard. Oh and there’s that isn’t there. It’s portable for sure, I’ve added the shoulder strap as the V2s are very dense and weight more than they look like they should (5kg for the pair). The pioneer Sub is compact but again reasonably heavy and the addition of the MDF inner shell for rigidity, battery pack etc the system is ~12kg more than I’d originally planned. Fine to throw in the car for a mate’s party, take out on a picnic etc but wouldn’t be carrying it in a 5km trail for camping etc.

It’s taken years and a lot of experimenting (with a few previous builds and a custom home system build prior) but I’m thrilled with the result, surprised even. The up2Stream Pro v3 with the improved DAC sub board has surprised me a lot, it’s really taken the Mirage V2s to shining and the sub with the much improved enclosure is into the top of 30s Hz wise and nice and tight, complementing the mains and filling the low end well. In the end considering the trial and error with parts, the tragic loss of the original Up2Stream and the luck of finding the mirages and the flight case I probably could have bought a decent Bluetooth speaker and been done with it, but not where near as much fun and I’ve ended up with something unique.

If I was starting the project now I’d look seriously at the Up2Stream with the 2.1 amp or the 2.1 plate amp, it would save trial and error (and therefore cost) and simplifiy the build process. Where too from here? I want to line the interior with thin neoprene to add protection during transit and fill the few milimeters around the Mirages. The wiring could certainly do with a tidy up and I’ll remove the noisy voltage regulator and mount the 5v battery pack for the board under where the Li ion battery pack is mounted, and add a battery level indicator (I currently use the step down converters display). And then many hours of happy listening.

An important note. One of the best things about Arylic (aside from the sound quality, the ability to switch to Bluetooth from a friends phone or spotify to hear a new track) is the support. I’ve had a couple of issues (the volume board had a faulty cable) and the team responded to email fast (already ahead of some brands) and the technical team worked with me to test the issues and find the problem. Once identified there was zero hesitation in sending me a replacement immediately at no cost (no haggling or “you broke it” junk you might get from other companies) which then worked perfectly. I’ve also emailed their technical team working through the board capacities and they know their stuff and are helpful people who are into sound. So important when you’re knee deep in a DIY build and pushing for sound quality thats worth it’s weight in gold.