Is there a Dolby B decoder plug-in? -Sound Forge - PC

Subject:Is there a Dolby B decoder plug-in? Posted by: walterh Date:10/25/2009 9:36:58 AM I have received CDs of concerts from the 1980s that were originally recorded on cassette tape. The tracks have that familiar hiss of a tape recorded with Dolby B and played back without it. The Noise reduction in Tools of Sound Forge 9 helps some, but I wonder if there isn't a plug-in specifically for this problem. I want to avoid going from CD to tape without Dolby then tape with Dolby to digital. Thanks in advance Message last edited on10/25/2009 9:37:58 AM bywalterh.
Subject:RE: Is there a Dolby B decoder plug-in? Reply by: musicvid10 Date:10/25/2009 10:15:58 AM Someone may have an EQ preset for this. Dolby B was pretty common. If you want to "roll your own," find the dolby specs on the internet, and construct a custom preset to negate some, but not all of the bias. I don't know how you would compensate for companding, so that's why I suggest taking a conservative approach. Here is the Dolby B white paper: http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/212_Dolby_B,_C_and_S_Noise_Reduction_Systems.pdf EDIT: There is a Winamp plugin that is highly rated that claims to do Dolby B removal. You could then use the wav out module in Winamp to write the file. I haven't looked into it. http://www.winamp.com/plugin/tape-restore-live/154246 Message last edited on10/25/2009 10:27:50 AM bymusicvid10.
Subject:RE: Is there a Dolby B decoder plug-in? Reply by: walterh Date:10/25/2009 6:08:49 PM I did find the Winamp plug-in. It works and has some other interesting features but you have to feed a track through winamp with the plug-in, adjust the settings to your liking then set winamp to output to a file and feed the files into wimamp. If the files are from a 2 hour recording it will take 2 hours for the last step. I also found this step by step instruction for using the Noise Reduction Tool in Sony Found Forge from an article in Digital Sound Pro: http://digitalprosound.digitalmedianet.com/articles/viewarticle.jsp?id=166554 It wasn't specifically for dealing with dolby encoding but seemed to work. It does require a silent section in the recording to work. I am not sure if this actually deals with the dolby problem other than remove the expanded tape hiss. Thank you for your suggestion
Subject:RE: Is there a Dolby B decoder plug-in? Reply by: musicvid10 Date:10/25/2009 7:05:15 PM I'm sure the NR approach will work better, but what we did in the seventies was to apply a 6dB cut starting at 4kHz. Kind of a "hatchet job" approach. Message last edited on10/25/2009 7:19:41 PM bymusicvid10.

Subject:Is there a Dolby B decoder plug-in?

Posted by: walterh

Date:10/25/2009 9:36:58 AM

I have received CDs of concerts from the 1980s that were originally recorded on cassette tape. The tracks have that familiar hiss of a tape recorded with Dolby B and played back without it. The Noise reduction in Tools of Sound Forge 9 helps some, but I wonder if there isn't a plug-in specifically for this problem. I want to avoid going from CD to tape without Dolby then tape with Dolby to digital.

Thanks in advance

Message last edited on10/25/2009 9:37:58 AM bywalterh.

Subject:RE: Is there a Dolby B decoder plug-in?

Reply by: musicvid10

Date:10/25/2009 10:15:58 AM

Someone may have an EQ preset for this. Dolby B was pretty common.

If you want to "roll your own," find the dolby specs on the internet, and construct a custom preset to negate some, but not all of the bias. I don't know how you would compensate for companding, so that's why I suggest taking a conservative approach.

Here is the Dolby B white paper:
http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/212_Dolby_B,_C_and_S_Noise_Reduction_Systems.pdf

EDIT: There is a Winamp plugin that is highly rated that claims to do Dolby B removal. You could then use the wav out module in Winamp to write the file. I haven't looked into it.
http://www.winamp.com/plugin/tape-restore-live/154246

Message last edited on10/25/2009 10:27:50 AM bymusicvid10.

Subject:RE: Is there a Dolby B decoder plug-in?

Reply by: walterh

Date:10/25/2009 6:08:49 PM

I did find the Winamp plug-in. It works and has some other interesting features but you have to feed a track through winamp with the plug-in, adjust the settings to your liking then set winamp to output to a file and feed the files into wimamp. If the files are from a 2 hour recording it will take 2 hours for the last step.

I also found this step by step instruction for using the Noise Reduction Tool in Sony Found Forge from an article in Digital Sound Pro:
http://digitalprosound.digitalmedianet.com/articles/viewarticle.jsp?id=166554
It wasn't specifically for dealing with dolby encoding but seemed to work. It does require a silent section in the recording to work. I am not sure if this actually deals with the dolby problem other than remove the expanded tape hiss.

Thank you for your suggestion

Subject:RE: Is there a Dolby B decoder plug-in?

Reply by: musicvid10

Date:10/25/2009 7:05:15 PM

I'm sure the NR approach will work better, but what we did in the seventies was to apply a 6dB cut starting at 4kHz. Kind of a "hatchet job" approach.

Message last edited on10/25/2009 7:19:41 PM bymusicvid10.