ASM Blog

Bring and Brag, ASM Get Togather

2012-01-25T11:59:00.000-06:00

Here are a few pictures from our January get together.

Our President opening the meeting

Club Treasurer Giving his CES report.

Gracious board member donating an OPPO for club use.

Presenting on annual donation to the Pavek

High Emotion meeting

2011-03-23T11:21:00.000-05:00

Mike Shields Principal Designer

ASM Fall Meetings September and October

2010-11-09T17:21:00.002-06:00

September, Paul Bolin spoke to the group.

October, John Wolff of Classic Audio Loudspeakers.

We also had a F5 Building Sub Meeting prior to the normal meeting.

ASM Speaker Project

2010-06-01T12:14:00.000-05:00

Here are a few pictures from the event. A full writeup to follow including cabinet drawings crossover and measurements.

Audio By VanAlstine and Nate’s Audio

2010-05-10T15:42:00.000-05:00

Bel Canto Design Meeting Highlights

2010-03-01T13:31:00.000-06:00

We Paid Our Membership to the Pavek

January swap meet and listening session

2010-01-26T10:41:00.001-06:00

The January meeting was a lot of fun. Here are some photos from the event.

ARC Meeting Highlights

2009-12-02T10:29:00.002-06:00

What can be said of our November meeting other than “Wow”! Not only were we treated to a “one-of-a-kind” tour of the Audio Research facilities in Plymouth, we were also the recipients of a very generous donation from Audio Research.

We are very fortunate to have a company like Audio Research in the Minneapolis area. Not only do they make world-class audio products, but also they are willing to open their doors and share their knowledge. They have been a long time supporter of the ASM and have proven it time and again. For those of you who were unable to attend the tour, Audio Research has generously donated a model SP-17 preamplifier to the Pavek Museum for use by the Audio Society

A simple “thank you” is not enough for the members of the ASM to give to Audio Research. The level of generosity and involvement that ARC has shown in our audio society is simply outstanding. The new preamplifier will certainly be a “crown jewel” in our system and be enjoyed for years to come!

Our tour and meeting was led by five key members of the Audio Research team: David Gordon, ARC’s North American Sales Manager, Terry Dorn, President, Warren Gehl, Materials Engineer and Quality Control Technician, Chris Ossanna, Field Service Technician, and Dennis Petrich, Product Design Engineer.

We began with a plant tour of the Audio Research facilities including the Production, Quality Control, Product Update, Engineering, Production Sound Room, Paneling and Stock Area

Production is planned by a three-month forecast. This allows ARC to determine materials and manpower needed for future production. It begins with “board stuffing” which involves preparing and cleaning circuit boards with very specialized and expensive solutions as well as hand wiring and soldering components to those boards. Specialized production workers each focus on unique tasks for each board culminating in a final Quality Control check before being passed on to the assembly area. Once all boards are assembled, they are tested, burned-in and retested before being passed on to the “chief listener” for final review. Once cleared, product nameplates are attached and the item is packed for shipment.

An interesting side note to ARC production is that Warren Gehl acts as the “chief listener” and he personally listens to each product before it is shipped out. This listening includes not only new products, but also products in for updating and service.

Following Production, we were able to tour the Service and Updates department. To show their long-term commitment to product support, we were able to watch a legendary SP-3 pre-amplifier being updated to SP-3C status. Company founder Bill Johnson strongly believed in customer service and support and set up ARC to offer upgrades to virtually any model of equipment ever produced at ARC.

To demonstrate the level of commitment for upgrades and service to its products, we toured the Paneling and Parts departments where we were amazed at the size of the parts inventory on hand. Part of that commitment is the availability of parts for older models and that created a sizable inventory. The Parts department also tests and grades all tubes and FETs. Because ARC maintains documents on each serial number shipped, it is possible for customers to get an exact tube or FET replacement if needed.

Finally, in Engineering, the room was filled with both modern and vintage test equipment. One ASM member even recognized a testing console that Bill Johnson personally used 35 years ago. Given the length of time ARC has been in existence, it is easy to understand why the engineering group has gathered such a wide variety of test gear.

With the completion of the factory tour, we moved to the listening rooms. Audio Research has two listening rooms: a smaller room for service and update evaluations and a large room for new products. The smaller room features Wilson Audio Watt/Puppy Series 8 speakers along and the large room features Wilson Max 2 speakers.

Being the “Chief Listener”, Warren Gehl was our host in the large listening room and demonstrated the versatility of the ARC products with various music selections. Utilizing the CD-8 CD player and driving the Wilsons with the new DSi-200 integrated amplifier, we were treated to a magical experience. The music was very natural sounding and well controlled. If given the opportunity, everyone would have stayed late into the night enjoying the set-up.

After our tour, we met for a Q&A session that included many questions about the new DSi-200 class “D” amplifier. Dennis Petrich, who was heavily involved with the products development offered great insight and offered us a very in-depth technical discussion about the merits of the product and the proprietary ARC technology utilized.

Terry Dorn ended our meeting with a totally unexpected surprise. Audio Research announced that it was donating a SP-17 preamplifier to the Pavek Museum for use by the Audio Society. The announcement brought a huge round of applause from the entire group. The model SP-17 is a current full-featured preamplifier that will provide our society with a state-of-the-art system and most importantly, one that has a remote control!

The Audio Society of Minnesota once again would like to thank Terry Dorn, David Gordon, Warren Gehl, Chris Ossanna, and Dennis Petrich for their time and hospitality. It was a memorable experience for all the members of the society and we genuinely look forward to using the donated equipment far into the future.

ASM Loudspeaker 101 meeting

2009-11-30T17:04:00.005-06:00

On December 8 at 7pm at the Pavek Museum of Broadcasting, coincident with the WAM Turntable setup meeting, we will be holding our second meeting for the members-only Loudspeaker 101 Tutorial Series. The topic is Thiele-Small measurements and box design. Please come join us, and bring questions!

In case the interested reader is not familiar with Thiele/Small parameters and wants to brush up, there are a number of resources on the web:
http://en.wikipedia.org/wiki/Thiele/Small
This wikipedia article has a useful description of terms section at the bottom along with some more technical/academic content at the top.
Many more articles on the topic can be found by searching for "thiele small" in your browser.
Notably, someone has posted Thiele and Small's articles from the 1960's and '70s at:
http://www.readresearch.co.uk/html/articles.htm

We may be able to demonstrate several different (see * below) free or inexpensive measurement systems that are targeted at the hobbyist (use a decent quality soundcard). Some examples...

Free:
* Speaker Workshop - http://www.speakerworkshop.com/
HolmImpulse - http://www.holmacoustics.com/holmimpulse.php

Inexpensive:
* Sound Easy - $200-300 - http://www.interdomain.net.au/~bodzio/
ARTA (free demo mode) - 80-150 Euros - http://www.fesb.hr/~mateljan/arta/

More expensive:
Praxis - (Free demo mode) - ~$1k - http://www.libinst.com/PRAXIS.htm

Once T/S parameters are known, box design can commence. At one time people were getting high dollars for box design programs. Many of these programs are superseded in quality and accuracy by free programs. It is quite possible now to design boxes without a financial outlay.

Some free box design/modeling programs that can be used:
WinISD - venerable program, the pro alpha version is more highly touted by users than the older WinISD beta, but the beta version is easier to use.
Unibox - free Excel spreadsheet that uses one universal model for sealed, vented, PR and bandpass enclosures. It is quite powerful, but can be difficult for beginners.
For the technically oriented, many of the design formulas may be found at www.diysubwoofers.org
Apart from downloadable software, there are many javascript calculators out there.

Remember that these models are simplifications and there is a law of diminishing returns on how complex you can make these things. Sometimes simpler is better.

The next few meetings will be held with a shorter hiatus, if possible, and we will characterize the drivers on a test baffle and start thinking on crossover design. We will also need to come up with a final aesthetic concept.

October 2009 Meeting-Turntable Setup and Optimization

2009-10-23T14:04:00.002-05:00

The Audio Society of Minnesota would like to thank Wally Malewicz of WAM Engineering for such a great presentation on turntable set-up and optimization. Wally is always entertaining, and all would agree that he went out of his way on Tuesday night to make a complex issue very entertaining. Thanks, Wally!

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Turntable set-up can be a daunting task. Let’s face it, our heads spin when faced with such a volume of acronyms. VTA, SRA, VTF, AS, zenith, azimuth etc. Setting up a turntable can be scary. By using humor as a foundation, Wally was able to explain and demonstrate each acronym and why it mattered. To compound the complexity of the discussion, the meeting was filled to capacity with users who needed answers. Beginners wanted to learn about fundamentals. Advanced users needed details. It didn’t matter; Wally handled each question without losing stride. Other than his Russian jokes, Wally kept the crowd fully entranced far into the night. In the end, all left happy and eager to go home to adjust their turntables with their new-found knowledge.

We have posted photos from the meeting as well as providing links to the articles Wally referenced during his presentation. Please take time to browse the page and take a look. The close-up photos of our Grado Reference cartridge are of special interest. One look at those photos and you will be online buying a USB microscope within minutes.
It was the use of an inexpensive USB microscope to assist in SRA/VTA set-up that drew the most attention at the meeting. With the microscope focused on the stylus, Wally was able to demonstrate the proper way to dial-in the Stylus Rake Angle (SRA) and Vertical Tracking Angle (VTA). Up until now, that has been done by ear alone. With the aid of the microscope, this angle can be definitively set and only tweaked by ear. Our system was a great example. By measuring our stylus angle and adjusting it by only one degree, the sound opened up and became more well-defined. In short, there is a very small “sweet-spot” for the SRA setting and the chance of doing it by ear alone is a formidable task. With the USB microscope, it was spot-on within a few minutes.

We always welcome Wally’s presentations and he certainly hit a homerun with his latest discussion. His insights are always informative and we look forward to seeing him again in the near future. From the members of the Audio Society of Minnesota, a sincere thank you.