Basspig's 2nd Annual Meet

I attended Mark "Basspig" Weiss's 2nd Annual B.A.S.S. meetup this year and had a great time, despite being a little under the weather with a headache and being late to arrive. He wrote a great summary of events so I won't type a redundant article, but I'll leave you with a reprint and some brief comments. I will add that there were also some interesting discussions on vinyl. Mark played back some digitally recorded demos of a how a laser turntable sounds vs. a standard electromechanical turntable. This later spurred some research on laser turntables and "high fidelity" records. Vinyl is a whole other world to learn about. While interesting, Its not something I'm going to get into. I do know one thing. I love the overhead Mark's system has and always enjoy hearing it. I have not heard any other system that has this powerful finesse. It reminds me of practitioners of Chen style Tai Chi who's art is calm and flowing but also deadly fast when needed. If there is one thing I'm reminded of that I need to do to my own system, it is to increase the displacement capability by several orders of magnitude. What a difference this makes, even at low volume levels. Stay tuned!


Mark's summary is as follows..

As with last year, our B.A.S.S. Meet was a great success!

Thank you to all who attended and brought so many great food items as well!

The main audio/video demo featured my Blu-ray productions of the Bridgeport Symphony Orchestra with Alex Beyer, performing Rachmaninoff's Piano Concerto No 3 in D minor, then the GBS performing Rachmaninoff's Symphony No 2 in E minor, (selected movements), then Allison Eldredge with the Boston Classical Orchestra, performing Saint-saens Concerto for Violoncello in A minor, then the Zambelli Ultimate Fireworks Blu-ray that I had the pleasure to capture from the launch pad, then I played a track from a Japanese soundtrack "The Weathering Continent" as a 2-channel Sonic Holography demo. Next up was a demonstration of the dbx 500 Subharmonic Synthesizer. For this demo, I used appropriate material lacking in fundamental bass (Average White Band "Pick Up the Pieces") and then gave an example of the absurd Bass Pig effect when you use it with Reggae music that DOES have some bass.

We took a break at the buffet and then returned to the Lab portion of the day where I demonstrated Bell Labs' new tri-tone test for Transient Intermodulation Distortion. We tested a Sansui AU-9500 against a Lepai 2020 amplifier. The results were colorful and interesting. The test setup consisted of three Tektronix SG5010 precision audio oscillators, outputting 10.05KHz, 9KHz and 20KHz, respectively, summed into a resistor network which fed each of the audio amps under test. I also performed traditional THD and SMPTE/DIN IMD testing. The Sansui easily tromped the Lepai on traditional tests, with ultra-low .028% THD, but the tables were turned when the tri-tone tests were performed, with the Lepai being an order of magnitude lower in TIM distortion than the Sansui.

And finally, I fired up the HP 8568B spectrum analyzer, connected to an outdoor antenna, and displayed the spectral mask of several FM stations, some with and without IBOC (In Band On Channel) or HD Radio digital transmission, discussing the effects on DX listening with the presence of the wider digital sidebands.

Our last guest showed a BD of Baraka on our big screen, which provided a colorful and sometimes disturbing look at life around the world, focused mainly around Asia.All in all, a positive experience, many questions and positive comments.

My Current System

** This page is a work in progress. I'll try to keep this up to date and linked on the homepage.**

Last Updated 3.28.13

My entertainment area occupies half the basement in my 1978 built home. The room is approx 12' wide by 45' deep with 7' ceilings. I wish it was wider and had more height, but its what I have to work with! I do plan on making changes to the walls and ceiling, so expect some updates. Front row seating is a 3-seat sofa with reclining ends. The front row is about 14' from the screen. Behind the sofa is a 6' wide DIY bar where there are 2 more seats. A DIY in-wall 19" equipment rack is to the left of the bar. Some DIY acoustic panels help with first reflection points. Most of my viewing is high definition Bluray concerts. I'm a music lover first and foremost. If I do watch a movie, it has to be a blockbuster. For this reason I hesitate to use the term "home theater". You'll notice that most of my upgrades from here on out will be geared as such. As you can see my decision to NOT go with a popular 2.35:1 Cinemascope screen, take my viewing habits into consideration.  

View from behind the bar (2nd row seating)

Behind the screen

10' x 5'  2.05:1 ratio CIA borderless AT screen

DIY 19" In-wall rack

Onkyo PR-SC885 Preamp & Processor. Handles all inputs from various sources, processes the audio streams and applies equalization based on the Audyssey XT room correction algorithms & measurements.

JVC RS40 Projector. A reference class 1080p 3D projector using D-ILA, or JVC's version of LCoS technology to produce an image with a high contrast ratio. I'm using a Chief mount, which after my previous DIY mounts, I HIGHLY recommend spending a little extra for a nice mount such as this.

Oppo 93 Bluray/SACD/Network Streamer with v1219 firmware. This is primarily my Bluray disc player. It is also an excellent network streamer for FLAC, MKVs, MP3s, ect. The firmware version I have installed still allowes playback of Bluray .ISO images, but only from a locally connected hard drive.

Popcorn Hour A-300 A low powered network media jukebox (NMJ) with the capability to play many media types, including Bluray .ISO images over a network drive, with full HDMI outputs bitstreaming HD audio codecs.

Seymor A/V Centerstage XD - Acoustically transparent screen material was used to construct a large screen of 10' wide by 5' tall. These screen dimensions give me the most bang for the buck on the 12'x7' wall. The ratio is considered a CIA, or constant image area screen and the ratio is 2.05:1. The concept was conveyed to me by  Anthony Grimani of PMI Ltd. while he lectured the Home Theater Cruise in 2009. I get maximum height while watching 16:9 ratio concerts, and maximum width while watching 2.35:1 cinemascope movies and can accomodate any ratio in between. The downside is the need for masking every ratio, which in reality is minimized by using a high contrast ratio projector. Not convinced? Click HERE. I made the screen frame from poplar wood and it is borderless. It floats from the joists above in front of the speakers. The fabric was stapled and placed on a bias to minimize moire patterns.

  

Marchand Bassis. A dual analog Linkwitz Transform circuit. Shapes the subwoofer output signal to counter the natural rolloff which occurs when using a non-ported (sealed) subwoofer design. It can be tailored specifically to match any sealed subwoofer design parameters to a given room's gain structure. I bought this as a kit, assembled and tested myself.

Crown CE4000 rack mounted amplifiers. Found at bargain prices on the used market, this model amp was the test bed for the future flagship I-Tech line of amps using an advanced derivative Class D architecture (which Crown calls Class I). Coupled with a power factor correcting switching power supply produces an extremely efficient amplifier. Powered with 240vac it draws very little current yet produces up to 3600 watts RMS bridged into a 4 ohm load. I use a pair of these on 240vac mains to drive a pair of sealed subwoofers. I also have replaced the internal cooling fans with Scythe S-Flex SFF-21D low noise fans for near non-existent noise levels.

Mackie HR series studio monitors. Models 824 (LEFT and RIGHT), 626 (CENTER) and 624 (SURROUNDS) Active studio monitors using a servo controlled midrange augmented by a passive radiator and a 1" dome tweeter on a mild waveguide. 

Acoupower Subwoofer System.  A DIY subwoofer system I created using a pair of Acoupower 18" drivers in sealed, down firing plywood cylinders. More information soon.

Acoupower Sealed Subwoofer Cabinets

Acoupower 18" Studio Driver

Furman PF-Pro R Surge protection and conditioning for all rack electronics (except subwoofer amplifiers)

Synology DS211 NAS  Raid file server 2x2TB soon to be upgraded with a larger Synology.

MISC EQUIPMENT :

• Assorted APC Battery backups
• Behringer Feedback Destroyer Pro - NOT IN USE
• Behringer Ultra Bass Subharmonic Synthesizer - NOT IN USE
• Quadcore PC

Acoupower Subwoofer Drivers

I compiled some videos about the subwoofer drivers in my audio system. It is an introduction and comprehensive look at the metal and soft parts which make up an Acoupower driver. You may have seen the introduction posted here before, but this includes videos of the inside of the drivers. A full 20 minutes worth. I'll soon publish a post showing the buildup of my cabinets and other data.

A quick summary of specs on these amazing 18" drivers :

- 6" copper 2 layer voice coil in an underhung configuration.
- Largest neodymium magnet used in any loudspeaker
- 97% of magnetic field lines in the gap
- Entrainment techniques used to eject hot air from the motor
- 5 sqft. of heatsink surrounding the motor
- 18mm of one way throw and still at 100% linearity on the BL curve.
- 39mm of one way peak throw
- 1% odd order distortion with 1KW input power

Ethan Winer's Basic Music Theory Videos

Ethan Winer put together a new set of videos explaining basic music theory. These are geared towards the musician and audiophile. This video packs a college-level course into about 2-1/2 hours using detailed explanations and familiar musical examples. However, it includes more than just music theory, such as showing playing techniques for musical instruments, plus a segment about orchestra conductors. Because of the length the video is divided into five segments. Full information is in the description for the first video in the list. Below is the first video, and a link to all 5 videos. Excellent material as usual. Check out all of Ethan's videos for interesting and educational subjects.

See All Parts Here (1-5)

Electronics Workbench Laboatory

I don't know what took so long. Maybe building cables on the concrete floor, taking laptops apart on the kitchen granite or building a Linkwitz Transform equalizer on the coffee table. What kind of electronics fanatic does not have a decent workbench? I set about to change this situation. Most of the materials I already had in stock and were recycled from other projects. Its a mix of warped 2x4s, 4x4s, Chinese Birch, Baltic Birch, screws and PL Premium adhesive. I don't have much equipment yet, but I have the basics. A good Weller soldering iron, Fluke Multimeter, 40v 5amp variable power supply, Tektronix 2465ACT Oscilliscope. A place to put my books, a computer, ect. The backbone of my home network sits on top. A pair of 8 port gigabit switches, a TP-Link router running DD-WRT, Linksys cable modem, Silicone Dust ATSC network tuner, and a Synology 211 NAS. To the immediate right of the bench is the back of my audio rack. There is even a Kenwood 599 Amateur Radio transmitter and receiver to play with. It is a work in progress, but I'm happy I finally have a start and a place to sit down and work on things.

Acoustic Panel Project - Absorption

Here are some simple broadband acoustic panels I made, based on the GIK 242.

The frames are made of 1" thick by 3.5" wide poplar. Poplar is used because of its resistance to warping. Finished panel size is roughly 2' x 4'. The pieces are joined with pocket screws via a Kreg jig, which by the way is a great tool to have! I didn't use any glue with these and they are super strong. The corners are simply butted together because once covered in fabric, they won't be seen. As an added touch, I chamfered the outer edge with a router. This was initially just for looks, but it also helps prevent snags when stretching the fabric over the edges. The absorption material used is 2" thick Owens Corning 703 rigid fiberglass panels, which have well known and documented acoustic properties. I then covered the panels with Guilford of Maine FR701 fabric, which is acoustically transparent and meets fire codes. The fabric is neatly stapled on the back side of the frames. The completed panel gives you 2" of absorber material with a 1.5" air gap behind it, which increases the low frequency performance and gives you a place to hang the panel onto a nail or screw. Performance wise, they should be identical to the popular GIK 242 panel as they use the same materials and specifications. I currently use 4 of these at the first reflection points of the left, center and right front speakers. 

Hometheatercruise.com

Hometheatercruise.com finally posted pictures from the past cruises
(Find me if you can!) What a great way to spend a vacation, cruising the Carribean and going to seminars with some great enthusiasts from the AVSForum and beyond. Plus you get to meet some industry leaders. (Some of which are a little snarky!) I won't be going this year, as the timing is bad for me, but i can highly recommend doing it at least once!

Subwoofer Location Tests

When I initially installed my Acoupower subwoofers, I placed them in the center, behind the screen and sat the center channel on the top. I knew this probably wasn't optimal for coverage of multiple seating locations, but it was a start. Having two subwoofer cabinets, at least they were mutually coupled and I would not have any phasing issues with the collocation. I decided it was time to move them around and see how the response changes. At the moment I don't have any way to separately adjust the phase or delay of the two independently so I have to strictly rely on physical placement and luck. Before making any changes, I setup my measurement system, a Windows 7 notebook computer with Room EQ Wizard software, my EMU0404 sound interface, and Nady CM100 condenser mic at the main listening position. I also turned off Audyssey MultEQ processing from the Onkyo Pro 885 and disabled the Linkwitz Transform circuit (Marchand Bassis) so I have a native raw room response. I also turned off all the active monitors, so only the subwoofer was being measured.

With the screen removed, here you can see the physical configuration of the LEFT, CENTER, RIGHT channels along with the Acoupower subwoofers in the center. As you can see, there isn't much room to jockey things around. The front wall is 12ft wide, however 2 ft of each corner starts a taper towards the wall due to triangular basstraps in each corner. The only solution was to place the LEFT and RIGHT monitors on top of the subwoofers as they were placed in the corners. This raised the tweeter level a little higher, which really isn't much of a problem, especially for my higher "second row seating".

And here is the new corner loaded configuration. The CENTER channel stand isn't the ideal stand, but it was all I had for the moment. I was also able to rotate the center vertically, keeping the tweeter height the same as the LEFT and RIGHT. I also introduced a bit of toe in on the LEFT and RIGHT channels, another listening experiment I wanted to try.

Now for the measurements...(click to enlarge)  This was taken at the MLP (main listening position) amd shows how both configurations measure without moving the microphone.

Interestingly, the response is all but identical from 15Hz to about 45Hz, with some deviation above that particularly around 90-100hz. Keep in mind, this is with absolutely no equalization at all and no smoothing of the graph. I still get the room gain down low, which works well with the sealed subwoofers and the upper end rolls off because the crossover in the Onkyo 885 is still enabled. I really should have taken multiple position measurements before I began, and again afterwards. I'm going to have to save that for next time and just use my ears for now. I am happy that there weren't any major cancellations or deep notches in the new response. This is probably due to the fact that each subwoofer is still equidistant to the mic and adjacent walls. The fact that the response changed insignificantly under 45 Hz is great news for a future modification I've been thinking of. So what did I learn here? The original center position on the subwoofers seem to be smoother around the crossover frequencies, at least in the main listening position. More tests to come, as well as more changes!

Measuring Projector Light Output

The newer JVC projectors appear to have an issue with bulb life. Some bulbs have been known to dim and or explode after a few hundred hours. I decided to get a cheap meter ($13) to measure the light output and monitor under consistent conditions as I accumulate hours. There is a test pattern in the service menu that throws a white screen with 9 circles that I use for placement of the meter sensor. Pictured is the center circle. The average of the 9 spots are 134.8 lux with 20 hours on the lamp in normal mode. Now I have a reference which to base future measurements. Normally this is a two handed operation, but I had to hold the camera too!

Dedicated Electrical Outlets

I finally got around to wiring some dedicated outlets above the rack. I'll now have a dedicated 120v-20a duplex outlet for rack electronics, and a 240v-20a duplex outlet for my subwoofer amplifiers - Crown CE4000s. Next up I need to recalibrate, as the amplifiers now are running with their fullest gain potential, 3600 watts into 4 ohms. each. Progress!