DIY AUDIO LDR kit projects

Two years ago after Googling my eyeballs out I discovered Rob Mackinlay's 505 ESL Mini Panel kit and decided to take a plunge into the ESL ‘sound’.

 

Under $800 per pair, ready to plug and play seemed like a cheap way to see if I liked the ESL sound. I could always sell them on if I wasn't impressed

 

I had no idea how I was going to mount them at this stage so I sat them on top of a couple of chairs with open backs and played a few tracks.

 

No way was I expecting to hear such open transparent, detailed sound, floating sound that had no boundaries unlike a boxed speaker.

 

I was on my path to 2 years of discovery, disappointment and frustration to the point of nearly canning the whole project.

 

Bass and mids were the first hurdle to overcome and a 6.5 inch Satori MW16P-8 seemed to be a good option.

 

My theory was that an upward firing bass speaker with the ESL panel mounted directly over the centre would be the answer. I was totally wrong as it sounded boring and had no coherency.

 

The final first enclosure was a sealed 15 litres made from professionally mitred sides and top. Material was 19mm MDF veneered both sides with American Oak.

 

The ESL power supply is mounted in a compartment in the bottom of the enclosure for easy access.

 

The ESLs were mounted in 15mm wide grooves routed into 20mm thick perspex upright/brackets. The brackets were bolted onto a plate and screwed to the top of the enclosure so it could be rotated or removed in seconds.

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PROBLEM 1

Excess bass output: The Satori overpowered the ESL and required around 10dB attenuation. 

 

Because I was using a stereo amp, the only option was to attenuate the Satori with an L-pad voltage divider but the Satori seemed to be struggling a bit without any dynamics.

 

PROBLEM 2

Ever shifting crossover frequency decision: I experimented with 1st order and second order on the Satoris. The panel was supplied with a first order. Multiple crossover points between 200hZ to 400hZ were tested. They all sounded quite good but each required microscopic fine tuning of the attenuation every time I changed the crossover point.

 

After many months I settled on a first order 250hZ crossover point which resulted in a gentle transition between the bass/mids of the Satoris and mids of the ESLs.

 

I was delighted with the performance but had the textural sound of the Apogees was still locked into my brain and wasn't quite there yet.

 

I know now that the crossover/attenuation was assisting in making the Satoris sound unmusical and slightly out of phase, so they didn't quite become part of the performance.

 

Lugging both enclosures in and out of the garage at least once a day (around 600 times) tweaking the attenuation and changing enclosure volume gave me enormous back muscles and thigh muscles through squatting and lifting (I wish).

 

CONFESSION: I almost gave the whole project away a couple of times.

 

STARTING AGAIN: A hard decision to make.

 

NEW ENCLOSURES

My decision was to buy a pair of beautifully designed glossy white two pack ported enclosures from Wagner Online. They were expensive at $800 for the pair but they were designed and manufactured SB Acoustics specifically for the MW16-P satoris and came with all hardware and stuffing plus precise instructions. These enclosures are designed to use an SB Acoustics tweeter so I sealed the tweeter opening.

 

They perform flawlessly and I haven't had to touch them.

 

ACTIVE CROSSOVER

X-Kitz 2 way Active Crossover was chosen without ever reading a review but they only cost $150 for a pair with a choice of crossover point. I didn't want to go digital because some of Rob's ESL users reverted to passives as they weren't getting the same enjoyment factor from their systems.

 

My worry with the X-Kitz was the 4th order 24dB slope which might not allow for a gentle transition between ESLs and mid/woofer.

 

WRONG! A 300hZ enables the magic to happen and the performance is beyond my expectations, compared to any other system I have heard over the years.

 

NOTE: Bass to treble ratio can be adjusted within a fraction of a dB to get the balance exactly where you need it. The ESLs have zero attenuation applied because of their apparent lower output. 

 

For example, with a 100% REW Frequency Generator output from my MacBook,Treble output from the crossover is .420V at 1000hZ. Optimum Bass attenuation is set to .059V at 100hZ, so the difference is huge.

 

As a matter of interest I tested the baffle offset compensation on the crossover but it wasn't necessary so I have zeroed it.

 

FINAL IMPORTANT TWEAKS

A Zobel network is installed in parallel with the Satoris to reduce a slight rise in bass around crossover frequency, to reduce any interference with the ESLs.

 

A 3mH inductor in series with the Satoris has enabled my system to punch out more detailed, tighter bass at higher levels than before. There seems to be a big difference in the spacial positioning of mid/bass which wasn't apparent before.

 

My lively Chord C-Line interconnects have been changed to DIY 8mm wide, thin copper foil bought from Uriah Daley in the USA and set a Taiwanese single point ground pin RCA plugs. This provide a smoother and even more natural presentation.

 

Speaker cables are DIY 12Ga Dueland tinned copper in oiled cotton from Aurealis. This cable is brilliant in every respect and relatively cheap as termination is optional. To make frequent unplugging simple I chose to use inexpensive screw connected Sawtooth Banana Plugs from Selby.

 

VERTICALLY BIAMPED HYPEX POWER AMPS

2 x NC122 Hypex nCores with integrated 2020 StereoCoffee LDR attenuator and internal X-Kitz 2 way crossovers. Component to component audio connections were keep as short as possible between the StereoCoffee preamp, crossover and Hypex boards so interconnects play a smaller part in the final sound.

 

ESL PANEL POSITIONING IS CRITICAL

Moving the ESL panel back 65mm from the front of the mid/bass cabinet speaker can determine whether I am just enjoying great sound or hearing music so authentic that I constantly wonder how a tiny change like this can make such a difference to overall performance.

 

The final result is a unique and carefully optimised system that, to my ears, has zero noticeable colouration or audible distortion and enables the music to shine through in realistic microscopic detail without any listening fatigue.

 

• Amp with crossovers and StereoCoffee preamp plus 2 x Hypex nCore modules cost around $1000.

• Pair of ER Audio 505 mini panel ESLs cost under $800 with power supplies.

• Satori mid/bass with satori enclosures cost $1300

• Dueland tinned copper speaker cables for ESLs and mid/bass about $100

• Copper foil interconnects about $80 with RCAs

 

TOTAL UNDER $3900 ...Not bad!

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NOTE: REL T-Zero subs are sometimes used but not necessary except for heavy bass

 

The DIY bonus is I also gained hundreds of hours of experience courtesy of Chris Daly and Rob Mackinlay.