Subject: Re: Rationale for Critical Bands From: James Johnston <James.Johnston@xxxxxxxx> Date: Mon, 14 Jun 2010 11:12:24 -0700 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Ok, I'm a bit puzzled here. First, an auditory filter description, level dependent and overload sensitive though it is, does carry considerably more information along with it than the Bark Scale. Second, ditto for auditory filter description vs. ERB's. Now, I'm wondering what "confusion" you refer to, frankly. While it's application, rather than research, I am personally aware of several very common applications that use the idea of critical bands/ERB's, and ones that work quite well by using this "confusion" you refer to, in particular MPEG-1, especially Layer 3, oh, say, both Psychoacoustic models, but in particular Psychoacoustic Model 2. MPEG-2 AAC. AC3. DTS-HD and relatives. WMA and relatives. Just to name a few. Those of us, like me, who use such results understand that there is more going on, but that the basic concept of place vs. frequency is valid, and what was long ago described as an 'excitation pattern' will carry a substantial amount of information regarding what can and what cannot be detected in a given auditory stimulus. Obviously, there are a variety of other issues, which are handled in various fashions. Psychoacoustic models for codecs are interesting in quite some fashions, in that the time response at high levels must be handled at the same time as narrower frequency response at lower levels. The user, after all, has a "volume" (let's leave the market and lay confusion between loudness and intensity for another time, ok?) control, and can change the rules on you at will. You have to understand this when designing your codec. So, the real world has shown, absolutely conclusively, that the simplification to auditory filterbank has a very strong, clear application. I think most, if not all, who use it are quite aware of the simplification. (Although BLMD did have to be beat into a few folks' crania, I must admit.) jj Home.comcast.net/~retired_old_jj __________________________ James D. Johnston (jj@xxxxxxxx) CHIEF SCIENTIST - DTS, Inc. 425-814-3200, ext. 134 - office 425-814-3204 - fax 206-321-7449- mobile 11410 NE 122nd Way, Suite 100 Kirkland, WA 98034 This electronic transmission (and/or the documents accompanying it) may contain confidential and privileged information. Any unauthorized use, copying or distribution is prohibited. If you have received this communication in error, please notify DTS, Inc immediately by telephone (425-814-3200) and destroy the original message. Messages sent to and from us may be monitored. -----Original Message----- From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxx On Behalf Of Martin Braun Sent: Monday, June 14, 2010 10:25 AM To: AUDITORY@xxxxxxxx Subject: Re: [AUDITORY] Rationale for Critical Bands There is no difference between the concepts of the "auditory filter" and the "critical bandwidth", let alone in simplicity. Both are extremely oversimplified and loose, and thus have been causing unending confusion. Notice: This message and any included attachments are intended only for the use of the addressee, and may contain information that is privileged or confidential. If you are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please destroy the original message and any copies or printouts hereof.