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  »  New  The new FM Classical scene in Boston..  Be Glad It Lasted So Long!...  Off Air Audio Forum     47  132242  11-26-2009
08-16-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,249
Joined on 05-28-2004

Post #: 1
Post ID: 11439
Reply to: 11439
Open letter to WGBH.
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From: Romy
Sent: Sunday, August 16, 2009 10:37 PM
To: ****
Cc: ****
Subject: The Tanglewood LIVE problem: 3 millisecond delay

To WGBH production and technical stuff
CC:  to WCRB production and technical stuff

Guys,

I know that kept harassing you over the summer season with my complaints regarding very poor BSO orchestral balance from Tanglewood. I also know that you pretty much discard my complaint as the most of the Tanglewood BSO is still being broadcasted at sub-acceptable level. I know about the lightning disaster we had at the beginning of the season but I think the problem we have is not the Act of God but a pure man-made negligence that is VERY simple to fix.

Again, the essence of my complaint is that BSO is being broadcasted 90% of time with VERY strange mix. The total balance of the right and left channels is fine and when I measure subtraction right from left channels with my Rohde & Schwarz MSDC multiplex decoder then I have the numbers that I would associate with a proper stereo. However, the BSO does not have proper instruments positioning balance and it sound as the right and left channels are played in almost opposite phases. The center image is missing but in a very peculiar way: the wind sections are there but the lead instruments sounds like it being  played from everywhere but not from where it shall be. The continuously sounding notes are more or less properly positions but transient notes sound imaging-wise in some very strange locations. The Yo Ma’s cello sounds from behind the first violin section and Garrick Ohlsson piano’s high notes come from third chair of the first violin and the low notes come from … the shade’s ceiling.

I do not make the things up. I routinely schedule to record your broadcasts at 88.2/24 (I record mostly WGBH as the WCRB unfortunately too much kill sound with compression) and do pay attention to your sound. If any of you would actually listen critically what you are broadcasting out then you would experience what I describe. Interesting that WCRB, in addition to all their common problems, has the similar imaging distortion as the WGBH has. In the past I called to WGBH’s Denis (I do not know his last name, please forward this email to him) at ****  who was very cooperative and effective as he made his calls and somehow it fixed the problem most of the time. Well, I do not think that me calling on Sundays to your Broadcast Engineers shall be a way to fix a systemic problem with broadcast sound, shall it be not?

Anyhow, I spent today time analyzing the files from you broadcast and I think I have found the problem.  Take a look: this is end of the second movement of Brahms’s Piano Concerto No. 2. Take a look at the leading edge of the Garrick Ohlsson’s piano attack. It is clear that left channel runs ahead of right channel.

WGBH_Tanglewood_Problem.jpg

If you listed the following fragment (it is 100Meg in 88.2 KHz and 24bit, it has reduced quality as I converted it from 64bit file to regular WAW 32 bit for you,  so you shall be able to play it with regular 88K/24 sound card.)

http://www.mediafire.com/download.php?hvt2ehznino

..then you will hear that piano notes are mostly left channel-centered.

Now, listen this corrected file:

http://www.mediafire.com/download.php?nmtd1d35cjn

You can clearly hear that Garrick Ohlsson’s piano is in the middle of the stage and the orchestra has much more proper balance all together. What I did was elimination of the right channel delay by removing 3.525 millisecond from it. This is what you need to do – to synchronize the timing of the feed of your right and left channels.

Please let me know if you need any further assistance from me and I hope the problem will be fixed.

Rgs,
Roman Bessnow


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-17-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,249
Joined on 05-28-2004

Post #: 2
Post ID: 11457
Reply to: 11439
The arrival delay vs. feed delay.
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A site reader sent an email:

“…but if they are using spaced microphones and one is five feet further away from the soloist who is not dead center on the stage, then signal will be delayed by about 5 millisecomnds. Or if they are using a spot microphone that is five feet closer to the piano and feeding only one of the channels instead of being mixed into both, you'll get the same effect...”

Here is an interesting home-worn thinking for you people. If we presume that they have very narrow directivity microphones for a soloist, wrongly position or wrongly calibrated, and if we presume that they have separate two wrongly used microphones for each channel, then how the wrong arrival time from those soloists’ microphones would be different from the physical channel delay?

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
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  »  New  The new FM Classical scene in Boston..  Be Glad It Lasted So Long!...  Off Air Audio Forum     47  132242  11-26-2009
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