Tuesday, November 25, 2008

Sennheiser HD-280 pro headphones

The HD-280 pro's are closed-ear headphones designed for professional-quality monitoring. Sennheiser claims a frequency response of 8 to 25,000 Hz (-10 dB) and up to 32 dB of noise attenuation which make them particularly useful for in noisy environments. The long coiled cable has a 3.5mm jack with a 1/4" adapter that screws on for a solid connection. The street price is about $85 (hover your mouse over the picture to do a quick price check).

For the past 2 years my HD-280 pro headphones have gotten a moderate amount of use in a studio environment and they have stood up very well, in fact they still appear brand new. The HD-280 pro's are a tight fit and that is key to their deep bass response. I own a number of different subwoofers and the HD-280 pro's bass performance exceeds them all by at least an octave. I fondly call them my "pressure cans" partly because of their tight fit but mainly because that's what bass an octave below 20 Hz feels like. I've surprised myself many times listening to recordings that I thought I knew very well only to hear (feel) bass that I didn't know was even there. I fully believe Sennheiser's claim of frequency response down to 8 Hz.

The HD-280 pro headphones do an amazing job of attenuating external environmental noise. When you put them on you feel like you are in a quiet room. Sennheiser claims "up to 32 dB of attenuation" which may be true in the ultrasonic frequency range. My tests with a function generator show these attenuations with the following signal sources:

  • pink noise -6 dB
  • white Gaussian noise -9 dB
  • 100 Hz sine -1 dB
  • 400 Hz sine -3 dB
  • 1000 Hz sine -6 dB
  • 2000 Hz sine -9 dB
  • 4000 Hz sine -12 dB
  • 5000 Hz sine -15 dB
  • 7000 Hz sine -18 dB
  • 10000 Hz sine -24 dB
  • 14000 Hz sine -30 dB
The HD-280 pro's attenuation of external noise is a function of frequency. Above 400 Hz the attenuation appears to follow a -3 dB / octave reduction curve. Bass frequencies don't have much attenuation. The signal structure of white noise has less low frequency energy than pink noise which results in -3 dB more of attenuation.

Except for the 14 kHz high frequency sine wave test these numbers are all a lot lower than 32 dB but this needs to be put into comparison. Good foam earplugs will give a 30 dB reduction. The HD-280 pro's have better external isolation than any other headphone I've tried but they aren't in the same league as foam ear plugs. That said, the dB attenuation of the HD-280 pro headphones is very significant in that it creates a lower background noise floor which allows the use of a lower volume level while also improving the audibility of weak signals.

  • very accurate sound
  • deep bass pressure
  • attenuation of environmental noise

  • tight fit
  • large and heavy
  • top band messes up hairdo
  • must be worn correctly for deep bass performance

I highly recommend the Sennheiser HD-280 pro headphones to anyone who appreciates high quality audio at a value price. Bass enthusiasts and those who appreciate a quiet background environment will be pleased.

Monday, November 24, 2008

Black Friday deals 2008

Home Theater related Black Friday (Novemeber 28th) deals. Items with a star "*" are limited quantity "door buster" first-come-first-served deals.

  • Sony BDP-S350 1080p Blu-ray Disc Player $199.00
  • 300 [Blu-ray] $16.99
  • Reservoir Dogs (15th Anniversary) [Blu-ray] (1992) $11.99
  • I Am Legend [Blu-ray] $16.99
  • A Clockwork Orange [Blu-ray] $10.99
  • The Shining [Blu-ray] $11.99
  • March of the Penguins [Blu-ray] $9.99
  • The Road Warrior [Blu-ray] $13.95
  • Terminator 2: Judgment Day [Blu-ray] $11.95
  • Sky Captain & the World of Tomorrow [Blu-ray] $9.99
  • Black Snake Moan [Blu-ray] $9.99
  • Predator [Blu-ray] $12.99
  • Dreamgirls (Two-Disc Showstopper Edition) [Blu-ray] $9.99
  • The Mummy [Blu-ray] $15.95
  • Sweeney Todd: The Demon Barber of Fleet Street [Blu-ray] $16.99
  • Early Bird Blu-ray's 2 a.m. to 11 a.m. (Pacific time) on Friday, November 28th


  • Samsung Blu-Ray Player - $199.99
  • Insignia Blu-Ray Disc Player - $249.99
  • Sony Blu-ray Disc Player - $249.99
  • Transformers Blu-Ray Disc - $9.99
  • Samsung 46" Class 1080P LCD HDTV - $1099.99
  • Insignia 47" 1080P LCD HDTV - $999.99
  • LG 47" Class 1080P 120Hz LCD HDTV - $1499.98
  • Panasonic Viera 50" 720p Plasma HDTV TH-50PE8U - $899.99 *
  • Samsung 52" 1080p LCD HDTV LN52A580 - $1499.99 *
  • Mitsubishi 60" Class 1080P DLP HDTV - $999.99

Circuit City - possible going-out-of-business problem with returns
  • Samsung Blu-Ray Disc Player BDP1500 - $199.99
  • Reservoir Dogs Blu-ray Disc - $11.99
  • SAW Blu-ray Disc - $11.99
  • 007: Dr. No Blu-ray Disc - $17.99
  • Samsung 46" Widescreen 1080p LCD HDTV LN46A500 - $1,099.99 * or @Amazon for $1099
  • Samsung 50" Widescreen Plasma HDTV PN50A400 - $899.99
  • Sharp 52" 1080p LCD HDTV LC52SB55U - $1,499.99 or @Amazon for $1520
  • Mitsubishi 65" Home Theater 1080p DLP HDTV WD65735 - $1,199.99
  • The Untouchables Blu-ray disc - $9.99
  • Predator Blu-ray disc - $12.99
  • The Mummy Blu-ray disc - $15.99
  • The Hulk Blu-ray disc - $15.99


  • Sony Blu-Ray BDP-S350 Disc Player - $179.99
  • Samsung 42" PN42A400 720p Plasma HDTV - $699.99

  • Sony BDP-S350 Blu-Ray Disc Player - $179.99 *
  • 300 Blu-Ray disc - $19.99 * or @Amazon for $18
  • Sleeping Beauty Blu-Ray disc - $18.99 * or @Amazon for $20
  • Samsung 46" 1080p LN46A530 LCD HDTV - $1199.99
  • Samsung 52" 1080p 120Hz LN52A650 LCD HDTV - $2099.99 or @Amazon for $2059
  • Sony Bravia V-Series 52" 1080p LCD HDTV - $1799.99 or @Amazon for $1745
  • Sony Bravia W Series 52" 1080P LCD HDTV - $1999.99 * or @Amazon for $2016

  • Magnavox NB500MG9 BonusView 1.1 Blu-ray player - $128.00 *
  • Samsung BD-P1500 Blu-ray Player - $198.00
  • Blu-ray Movie: American Gangster - $15.00 *
  • Blu-ray Movie: Indiana Jones Crystal Skull 2-Disc Special Edition - $15.00 *
  • Blu-ray Movie: Iron Man Ultimate 2-Disc Edition - $15.00 *
  • Blu-ray Movie: Kung Fu Panda - $15.00 *
  • Blu-ray Movie: Shooter - $15.00 *
  • Blu-ray Movie: Transformers 2-Disc Special Edition - $15.00 *
  • Samsung 46" Widescreen 1080p LCD HDTV - $1,098.00
  • Samsung 50" Widescreen Plasma HDTV w/ 2 HDMI Inputs - $798.00 *

There are some great bargains here but many items can be purchased at roughly the same price on-line without the hassle of all the Black Friday crowds. So before you go out and shop make sure you do some price checking.

That's right. Shop smart, shop S-mart. Ya got that?

Wednesday, November 19, 2008

Netflix HD codec details

Netflix, Inc.New streaming HD codec details emerge from the Netflix blog.

For Xbox 360 and Silverlight platforms, Netflix will be streaming HD content using a 720p resolution with the VC-1 Advanced Profile codec at 24 FPS for movies and 30 FPS for video. The two bit rates are 2600 kbps and 3800 kbps so a fast broadband connection will be required. Audio will be limited to stereo only until they figure out how to package a multichannel AC3 audio stream in WMDRM10 (Windows Media Digital Rights Management).

Roku is saying that their Netflix HD streaming should be ready by the end of the year and will be available by an automatic firmware update. Roku claims that their "implementation of Netflix's HD content will take significantly less bandwidth that what is currently required on the Xbox" then they contradict themselves and say that "Roku Players will be using the 2.6 and 3.8 streams, which are the HD streams." So at this point it appears that the Roku box will be using the same VC-1 AP codec that the Xbox 360 and Silverlight platforms use.

Tuesday, November 18, 2008

The Terminator: Blu-ray vs. LaserDisc

The 1984 film The Terminator made by James Cameron stars Arnold Schwarzenegger, Linda Hamilton, and Michael Biehn. It is the classic action sci-fi cyborg thriller flick.

I purchased the THX certified LaserDisc of The Terminator in 1995. It wasn't a reference quality LaserDisc like the THX pressing of the Terminator 2 directors cut by any means but it wasn't a bad transfer either. The original was a low budget production and to reduce costs the film was mixed with mono audio. I have enjoyed watching this movie many times over the past decade, it was a good purchase.

The Blu-ray version of The Terminator is a BD25 disc that uses the MPEG-2 video compression codec at an average 18.54 Mbps data rate. The picture visuals are far from reference quality but they are a huge step up from the THX LaserDisc. Video noise is mostly absent and the image isn't that grainy. The Blu-ray also has much more detail and is cleaner than the LaserDisc. Unfortunately these improvements have a downside in that the special effects shots are now more obvious and fake looking. It's a good looking disc and the extra detail provides a definite high-defness. This is probably the best The Terminator will ever look and it is a dramatic improvement over the old THX LaserDisc.

The old THX LaserDisc, as did the theatrical release, had a mono audio track. Cameron had a limited budget for Terminator and decided to spend the available funds on special effects instead of on a surround soundtrack. This was a good choice as the SFX really made the film work. The mono track obviously lacked any stereo or directional sound information. The mono track also lacked bass and sort of dynamics during the scenes with gunshots and explosions.

Several years ago Terminator was remixed with multichannel surround and many sound effects were recreated. The Blu-ray has an uncompressed LPCM 5.1 16-bit sound track along with a 640 kbps AC3 5.1 track those with older audio equipment. This new remixed audio track is impressive with strong bass and extreme dynamics. The battle scenes now have a kinetic sound force that matches the intense action on screen. You can hear the bullets whizzing around the room. Directional pans add a nice touch to some scenes. The rear surround channels are used throughout the film for an added ambience; urban city noise, crickets near the woods, humming sodium lamps in the parking garage, and buzzing machines in the tool shop. One strange ambient surround effect is the choice of crickets inside Sarah Conner's apartment. What are crickets doing inside? Other than that slight flaw, the sound design is well done and almost a bit over the top in some action spots. I enjoyed the new 5.1 remix immensely and it is a huge improvement over the mono track. This is the surround sound track that Cameron probably wanted originally but couldn't afford.

So what about purity of essence and faithful reproduction of the original version? Is 5.1 remixing like B&W colorization or the adding of CG effects years later? The 5.1 remix definitely has more impact and excitement than the original mono track which was lackluster and boring. So as a home theater enthusiast I like this new 5.1 mix but it would of been nice, form a purity of essence standpoint, if they included a compressed version of the original mono track for posterity. Other than for comparisons, I probably would never listen to the mono track but it's the sort of thing that should be included these days with multi-gigabyte Blu-ray discs.

The video and the audio of the Terminator Blu-ray are huge improvements over the old THX LaserDisc. The Blu-ray video has fine high-def details but it isn't close to being reference quality. The 5.1 remix has strong bass, explosive dynamics, nice directional pans, and enveloping surrounds. The Blu-ray provides a better viewing experience and I'll probably be watching The Terminator a lot more often now.

Highly recommended.

Monday, November 10, 2008

0 dB THX reference level

The THX 0 dB reference level is a calibrated volume setting used in dubbing, cinema, and home theaters. The 0 dB (decibel) setting represents an average 85 dB SPL (sound pressure level). Movie soundtracks are created and mixed in dubbing theaters. Movies are presented and played back in cinema and home theaters. The general goal of the reference level is to preserve the directors intent which is to ensure that the volume level that the movie was created (mixed) at is the same as the playback volume.

Pink noise and a sound pressure level (SPL) meter with C-weighting are used to calibrate the individual 5.1 or 7.1 speaker levels. This calibration balances all of the speakers levels so that they are equal and that no speaker is louder than any other. The calibration also sets the 0 dB volume setting to equal the THX reference level. Both internal and external pink noise signal sources can be used to calibrate the speaker levels. External calibration signals found on video discs are typically full range pink noise at a 85 dB SPL. A preamp/receiver's internal calibration signal is typically banded pink noise played at a 75 dB SPL which is -10 dB down from the reference level. The quieter -10 dB signal is chosen by manufacturers because it is less harsh for users. It is also important to note that banded pink noise and full range pink noise will produce dB level settings that are slightly different. Which one equates to the true reference level depends on who you ask and how flat the frequency response of your speakers are.

Maximum Level
The 0 dB reference level represents an average 85 dB SPL and a maximum 105 dB SPL. The LFE (Low Frequency Effects) channel used by AC3 (Dolby Digital) and DTS is +10 dB higher. This means that the maximum output for bass peaks is 115 dB SPL. The purpose of the +10 dB gain for the LFE channel is to increase the dynamic range of bass events such as explosions, crashes, punches, and rumbles. This means when the volume is set to 0 dB that the subwoofer could be asked to produce an output of 115 dB SPL. Such loud bass levels places a heavy resource burden and requires multiple high-end subwoofers to produce it accurately. Fortunately THX processors have a feature called the Bass Peak Limiter which compresses peak levels in an attempt to reduce distortion and prevent speaker damage.

THX theaters
The THX certification process for cinema theaters has numerous audio and visual quality control assurances that must be met. This THX stamp of approval ensures that the movie looks and sounds good. The 0 dB THX reference level is part of this quality assurance and the volume control knob is usually behind a locked panel so that it cannot be adjusted. This ensures that all movies played in a THX certified theater are played at the correct THX 0 dB reference level. Unfortunately a 0 dB volume level is too loud for many patrons and cinema owners so over time many certified THX theaters will have their "locked" reference volume levels reduced. If the rules aren't enforced then what use are rules?

THX equipment
A related benefit of the 0 dB reference level is the requirement that home THX certified equipment, particularly amps and speakers, be able to reproduce volume at this level without distress. Originally two 12" subwoofers were required to meet the THX spec for large rooms. An output level of 105 dB isn't an easy task at 20 - 40 Hz for subwoofers, especially when the +10 dB LFE channel is accounted for. Actually this output spec has been relaxed a lot during the past decade so that a single smaller sub can meet it. This "practicality" was probably due to pressure from consumers and manufacturers.

The 0 dB THX reference level is a wonderful concept for many other reasons. It creates a standard for comparing playback volume levels. If you and I both have our systems calibrated to the reference level then when I say that watched that movie at volume setting of -15 dB then you will know what I mean and you will have a general feeling for how loud that is.

The engineer in me really likes having the volume control operate with units of dB. And the fact the 0 dB level is actually a reference to something makes it even better. I don't know what is but that dB display just soothes my soul. In fact I won't buy a preamp or receiver that doesn't have it.

Watching a movie at 0 dB is crazy loud and I rarely watch a movie anywhere near that level. It depends a lot on the movie but I tend to watch movies with the volume set between -17 and -11 dB. For some very quietly mixed movies I tend to go up to about -5 dB. I love loud bass and I also love my hearing. I just don't understand how the professional sound mixers can listen to their craftwork at the 0 dB reference level for 8 hours a day, 5 days a week, without suffering any permanent hearing damage. According to the OSHA occupational noise exposure levels A-weighted SPL's of 90 dB for 8 hours, 105 dB for 1 hours, and115 dB for 15 minutes per day are allowed.

I'm a fan of THX technology and it is kind of sad seeing the slow dilution of the 0 dB reference level specifications. The THX stamp at the cinema and in the home just doesn't mean what it used to.

Wednesday, November 5, 2008

Amazon's Blu-ray Buy 2 Get 1 Free

Amazon is having another one of its Blu-ray buy 2 get 1 free deal that runs until November 6th 2008. The selection this time is very similar to the B2G1F sale in the middle of June. Slow but free shipping is also available.

The way to get the most out of this deal is to choose 3 discs that are all the same price. This time the biggest selection and best deals are the $20 discs which works out to a little more than $13 per disc.

$20 * 2 / 3 = $13
  • The Fifth Element (Remastered)
  • Hellboy (Director's Cut)
  • Underworld (Unrated)
  • Black Hawk Down
  • Bram Stoker's Dracula
  • Gattaca
  • The Patriot (Extended Cut)
  • Resident Evil
  • House of Flying Daggers
  • The Adventures of Baron Munchausen
  • Memoirs of a Geisha
  • Memento
  • Resident Evil: Apocalypse
  • Dogma
  • Run Lola Run
  • A Knight's Tale
  • A Few Good Men
  • Seven Years in Tibet
  • Monty Python's Life Of Brian - The Immaculate Edition
  • Wild Things (Unrated Edition)
  • Cruel Intentions
  • Immortal Beloved
  • Secret Window

The Fifth Element and Hellboy have excellent Blu-ray picture quality and are visual treats. Bram Stoker's Dracula is a great film but this Blu-ray has a very soft picture quality and the fine detail and resolution look the same as on the old anamorphic DVD. Happy Shopping.

Monday, November 3, 2008

Netflix HD Streaming

Netflix, Inc.Netflix HD streaming will be available late 2008 for the Roku, Xbox 360, TiVo, and both the LG and Samsung Blu-ray players. Unlimited streaming is included with the $9/month and up plans. An 8 Mbps broadband connection will be required for the top quality level. The video encoding will be MPEG-4 Advanced Profile with a 720p resolution. Since this is a different codec from what is used by the Xbox which means that different digital streams will need to be encoded and stored on the Netflix servers. No mention if Dolby 5.1 AC3 surround audio will be streamed,

The Roku engineers hinted that "a new major feature" will be included in the update but they did not specify what it might be. Speculation is that the Netflix Roku box will gain network audio streaming which is a common feature with Roku's other products.