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Monday, February 16, 2015

Audio Nirvana


Blog on Audio Nirvana Super 12 full range drivers from a friend of ours. We got a sample from Commonsense Audio quite some time ago and promised a write-up on their drivers. Apologies for taking so long. :)

Here goes the unaltered write-up from Thomas, a customer of our transformers, a seasoned audiophile friend, a long time friend and a distant brother-in-law of our founder!

My journey to audio nirvana

My journey to audio nirvana began a long time ago in varsity (1983 to be exact) starting with entry level gear (analog of course) – The AR turntable, Rotel 820 integrated amplifier, Mission700.2 speakers – stuff that would fit a student’s tight budget.

Upon graduation, my system and lifestyle evolved in keeping with my ever-increasing disposable income.  Vacuum-tube gear started taking over the backend in 1998 with some DIY efforts. My current system has since settled down to a DIY SET 6C33C-B power amplifier driven by a #26 tube preamplifier. Speakers are Musical Technology Kestrels, but I had always deemed the 86dB Kestrels to be too heavy a load for my 15W power amplifier. And so the quest to find an SET-friendly (read high efficiency) speaker was begun a few years ago. Before long I had on hand Coral and Fostex 8” drivers to try out.

As fate would have it, audio blogger Ken Loo (http://www.diy-audio-guide.com - obsoleted, now is this blog!) introduced me to Audio Nirvana’s Super 12 full-range drivers. OMG, a whopping 12-incher! So size really does matter and I could no longer resist the prospect of high-efficiency speakers doing justice to the many vocal oldies in my LP collection. Since I neither have the skill nor the equipment to cut perfectly circular holes for the drivers, Ken, a resourceful DIYer himself, located a cabinet maker to help me build the cabinets according to CommonSense Audio’s recommended specifications. I chose the dual-port version.

A few weeks later, they were safely in my house.  The cabs are constructed from 18mm MDF (middle density fiberboard). First I had to make sure that the all-important 279mm (11 in) holes for the drivers were accurately cut. Indeed they were. So far so good.

DIY Speaker Box
Audio Nirvana 12" Speaker Driver
That’s just the beginning. Next I had to decide what damping material was needed. After some trial and error, I settled on some readily available silicone floor mats and foam slabs. Two layers of silicone mats cover the insides other than directly behind the driver, where the foam slabs reside. At the bottom cavity, I placed polyester-filled pillow bags to further absorb reflected waves.
Padded speaker box with damping sheets and foam
Damping sheets

Initial impressions

Straight off, I loved the clarity of the mid-range. The music flowed effortlessly, with more than enough head room to spare. There was no in-the-face, fatigue-inducing highs that I had read about that characterized some high-efficiency full rangers. I was sold!

But with the much higher speaker efficiency, I could now hear a soft but audible 50Hz hum. It was traced to the dreaded affliction common to the #26 tube in my preamplifier – the hum induced by the heater supply. Due to my many other priorities (my audio hobby is never a priority), it took all of another year to sort that out. My #26 preamplifier re-vamp is another long tale in itself. For now, I’d just say I had to have it totally gutted – new (low noise) heater regulators (from Tentlabs), B+ shunt regulator (from KandK Audio), more bypass capacitors, B+ filtering re-design, grounding re-route, grid choke, etc.

With that solved, I settled down to more critical listening with the Audio Nirvana Super 12s.
Without the annoying hum, the enjoyment went up a big notch, but after a while I realized that the bass just didn’t sound right - there wasn’t enough of it in some of my favorite music when compared to my Kestrels. Even my non-audiophile wife preferred the old speakers, which, she commented, had more “enveloping bass”. I suspected it could have to do with the ports. Using an online port calculator, I obtained a length of 16.6cm for a 3-inch vent at 40Hz.

DIY Port

Raw appeal

It’s not easy to get proper speaker ports locally so I went to the hardware store to get some ideas. The closest the store had are pipe sections which, after some sawing and gluing, I had my ports. And what a difference the ports made!

The bass became more “directed” rather than dispersed, with more impact and it went deeper.  LP after LP, I found new enjoyment and purpose in pursuing this audio journey.

The music
Creedence Clearwater Revival

Willie Nelson - Stardust

Tracy Chapman
In my smallish 11ft x 12ft listening room, these speakers have no trouble pumping CCR’s “Have You Ever Seen The Rain” to ear-splitting level with just 15W from my 6C33C-B SET power amplifier. The bass really rocks! In Tracy Chapman’s original LP of the same name, “Talkin' bout a Revolution” has every breath and highs clearly fleshed out.  The rattling of the tambourine hangs in the air right in front of me, and drum beats are uncannily three-dimensional. Goose bumps! 
And how about vocal oldies?

Patsy Cline's
Patsy Cline is one of my all-time country crooner, with a melodious voice that transports you to another time. A system that’s not up the task will be excruciating to the ear. Analogue Productions’ latest reissue of her “Greatest Hits” (Decca DL74854) is sheer joy, with Patsy solidly planted in my listening room. For male country, Mobile Fidelity’s re-issue of Willie Nelson’s “Stardust” is just the ticket.  I have since been playing “All of Me” over and over again just to listen to the guitar and drum passage - the palpability just drives me crazy!

Nat King Cole

In Nat King Cole’s “Looking Back” (Nat King Cole Story Vol 3, Capitol W1928), in mono, Nat sounded really in-the-room, clear as day, and full-bodied; a relaxing and dreamy style that’s just perfect for a lazy Sunday afternoon. Yes, a lazy Sunday afternoon in audio nirvana. And all throughout my listening sessions, I did not for a moment feel any listening fatigue.
Thank you CommonSense Audio for bringing nirvana to my home.
 
HIFI system with Audio Nirvana Speakers

Audio Nirvana Speakers
Equipment:
Turntable: Vpi Mk 3 with AudioQuest PT-6 tonearm
Cartridge: Koetsu Rosewood Standard
Phonostage: Pentagon PS-3
SUT: Lundahl LL9206 at 10:1
Preamplifier: DIY #26  tube and Stevens & Billington Tx102 transformer attenuators
Power amplifier: DIY SET 6C33C-B
Speakers : Musical Technology Kestrel and DIY Audio Nirvana Super 12
Cables and Interconnects: Art Chamber custom-built with vintage Western Electric wires

Signing off!

J&K Audio Design
17/2/2015

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* Finished amplifiers, DACs, audio gadgets, upgrades and repairs - this is not our core business and we do it out of passion. We do not have fixed models, fixed price and we customize for each individuals. The sky is limit of creativity.

* Our product lines are always improving and increasing. If you do not see what you want, contact us!

* Please email for volume discounts, distributor and OEM pricing.

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