DIY AUDIO LDR kit projects

BUILDING MY HYBRID ER AUDIO 505 ESL PANEL SYSTEM (UPDATED April 2020)

The fuss free way.

​

DISCLAIMER: I had never heard an ESL before I built Rob's kit but I had heard Apogee Ribbons (I thought they were ESL's) and was amazed at the lack of colouration and realism. After reading a post on StereoNet forum about Rob's 505's decided to take the plunge despite being obsessed with my LS50's. 

 

After placing my order with Rob Mackinlay, the 505 ESL kit arrived a few days after Rob built and customised it to suit my requirements. www.eraudio.com.au 

​

The 505s kit is virtually plug and play and includes specifically designed heavy duty power supplies and extensive instructions.

​

MOUNTING ELS PANELS CAN BE A CHALLENGE but this is a quick solution and works effectively.

​

After many iterations over 2 years I settled on mounting my pair of panels by attaching them to 25 x 12mm upright aluminium extrusions from Bunnings.

​

The Power supply is mounted upside down in a folded piece of 3mm A4 perspex case and the aluminium uprights are bolted to the inside of the power supply box sides. Slots in the top allow the extrusions to be slid backwards. The panels have stretchy speaker fabric socks and are attached by two pieces of elastic that hold them securely against the uprights using and attached using holes drilled in the uprights at the top and 3/4 of the way down. (pic #3)

​

The power boxes sit on top of the bass enclosures on neoprene feet to stop vibration to the panels. The benefit is that they can be removed for adjustments, if necessary by unplugging them.

​

ONE ACCIDENTAL IMPROVEMENT THAT BLEW MY SOCKS OFF!

 

I was totally wrong in thinking the 505s would sound better if they were unrestricted and free to move slightly with plastic clips. I decided to tweak my panel mounts as a Covid-19 project and securing them with scrap elastic from my wife's sewing box seemed a simple temporary solution as I didn't have a way to re-mount them. Now they are permanent!

​

This simple change suddenly made them 'grow up' into adults. The experience now is not just involving, it is powerful and overwhelming when required by the performance.

 

WHY START MY SYSTEM FROM SCRATCH AGAIN?

 

My original build with a timber American Oak enclosure and passive crossover has now been abandoned after 2 years of enjoyable experimentation.

​

One of the main problems I encountered was the difficulty matching output balance between the ESLs and Satori MW16P-8 mid-woofers. I thought my previous attempts using passive crossovers sounded excellent but I didn't anticipate the improvement I would get using an active crossover and Class D bi-amping with dedicated bass and ESL amplifiers.

​

I use bi-amped two Hypex nCore NC122 modules in professionally built Ghent enclosures with dual American X-kitz active 2 way analog crossover boards which cost me $150 delivered from the USA.

​

ACTIVE CROSSOVER

The X-kitz 2 way passive crossover can be ordered with a crossover point that you request. I chose 300hZ because it seemed to sit comfortably with the ESLs without intrusion from the mid/woofers. The crossover point was changed by swapping the supplied crossover modules with DIY 275hZ. Modules can be built by soldering 10 ant sized resistors into a plug for each board.

​

No soldering is required and they can be ordered with balanced outputs or RCA connections.

​

Setup success is fast.

 

The only job is to calibrate the power supply output using a voltmeter and multi turn pot. Levels adjustment can be done two ways with hybrid ESL panels. (ESLs FIRST not bass)

​

With the both boards powered up and your crossover point modules in place, do the following on each board.

 

1. Using a 1500hZ sine wave, make note the A/C output from the signal source. If it is 1 volt, adjust both treble trim pots until the output is also 1 volt (parity).

​

2. Using a 50hZ sine wave, measure the bass output from the board. Because the bass speaker will most likely be more sensitive, adjust both bass trim pot to read .75 mV.

​

This will give you a left to right balanced output BUT the bass may have to be attenuated more by ear because the bass/ESL balance is super critical. Bass must not muddy the ESL magic.

​

The crossover is placed between the preamplifier output and amplifier inputs, but I chose to integrate my crossovers with a StereoCoffee LDR preamp board because of its zero colouration, and sound purity which is on a par with the best valve preamps and better than any LDR preamp according to high end users. (pic #4)

​

The cost to build this integrated StereoCoffee/X-kitz preamp is around $350 for a 3 input StereoCoffee set of boards and $150 for the X-kitz active 2 way crossover plus a case and 12 volt A/C plug pack and a good quality 12 to 20 volt plug pack for the crossover boards to share.

​

BASS ENCLOSURES

Because to 505s deserve better enclosures than my timber attempts, I decided to go whole hog and find a prebuilt pair of enclosures. Luck was on my side, because SB Audio, makers of the Satori MW16P-8 bass woofers I am using, design and manufacture 2 way enclosures designed specifically for these drivers. They are superbly finished and come complete with hardware and stuffing. The tweeter cutout was blocked off so that the enclosure was only used for bass/mids.

​

WHY I SETTLED ON PREBUILT ENCLOSURES

12 months were spent making multiple daily trips to my work bench changing components and trying to understand crossovers and enclosure volume. It took me 2 years to realise how little I knew and how I might be tweaking forever.

​

WHY CHOOSE THESE SATORIS?

The MW16P-8 6.5 inch Satoris have very flat output and impedance curves which, in my opinion, would make performance more predictable by not adding more impedance variation for the ESLs to compete with. than necessary. (pic #5)

​

FINISHED AT LAST

Now my 505 Mini ESL’s finished and running. Absolutely extraordinary performance and way beyond my expectations which were already very high.

 

Don't let the size of this small panels fool you. The sound is fuller, more dynamic and smoother than my KEF LS50's which are no slouches. They are extremely punchy not polite. It's a sonic revelation to hear everything, including instruments and voice sounding 3D and realistic, without any cabinet interference. I have been startled on more than one occasion when an instrument or voice appears from nowhere to be in my room with me. 

​

SPEAKER POSITIONING

CRITICAL: Distance from the rear wall can have a profound effect on the ESL magic sound. My experiments have shown that 50mm movement can improve or hinder the performance. I believe this is due to the cancellations or increases in level that occur from the sound reflected back from the rear wall which are probably caused by phase shifts. The ported woofer performance can be fine tuned by the distance from the wall.

​

My final setup has speakers less than 2 metres apart (dictated by cabinet) and panels 500 mm from the rear wall/window. This seems to provide a super wide sound stage with instruments way outside the speakers and the sweet spot is much wider and easier to pick. Mid/bass is more coherent. No toe in or toe out is used however toe in is useful for fine tuning as panels seem to vary slightly.

 

INTERCONNECT CHOICES CAN MAKE A  BIG DIFFERENCE 

These little ESL’s are so accurate they WILL reveal any system inadequacies or changes you make in the signal chain. I tried pure copper, copper foil and pure silver in various combinations with speakers but only copper foil blew me away until the Dueland tinned copper.

 

• Speaker cables: (ESLs) Dueland 12Ga tinned copper in cotton/oil sheath. and Dueland 16Ga on woofers. Replica of Western Electric, sound and unbelievably open and dynamic.

• Termination: Z plug connectors from Selby.

• ARIES Mini music streaming

• StereoCoffee LDR Passive Preamp/ Active analog crossovers: 

• Preamp to dual HYPEX nCore in Ghent enclosures

• Interconnects: Chord C-Line budget cables. Don't be misled by the low price. These cables out perform ALL my attempts from copper foils, silver, solid copper and have a beyond average detail throughout all frequencies with outstanding bass control. (My favourite RCAs have been binned)

 

THE SOUND

• Accurate separation of instruments and voices, each with their own space in the same sound stage.

• Super wide sound stage with holographic experiences in well recorded live recordings.

• The lack of boxiness is noticeable from the first note.

• The start of any performance makes a big statement and never fails to surprise me as it leaps out of a TOTALLY silent background provided by the StereoCoffee and HYPEX.

• The ESL sound seems the have the ability to float around the house and maintain it's clarity.

• Sound still maintains its character and enjoyment sitting to the side of panels.

• Instruments like a double bass and cello seem to have body depth.

• Punchy performances with balanced and detailed bass, even with sub woofer.  I am a fan of KEF LS50's but the 505's dynamics just make the LS50s sound a bit dull, and the wider than wide sound stage and lack of cabinet effects put the 505's performance in a different league.
   

* Sound is in the ears of the beholder so your opinion may be different to mine. My preference is intimate listening where sound is smooth but detailed, instruments and voices sound accurate with no colouration and performances are punchy and exciting. I like bass to be in proportion and each instrument clearly defined. Stringed instruments must have texture and overtones that convey the resonances of the instrument body. The 505's do this but positioning, balance and interconnects can make a big difference.

 

SYSTEM TOTAL COST under $4000

 

*Subs aren't necessary on most  music.

​

DISCLAIMER: I have no financial connection with these suppliers. I am just a delighted customer.

​