<HTML>In a message dated 5/11/01 11:21:12 PM Central Daylight Time, Tvak@AOL.COM writes:  Wim wrote: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"><< When we come home in my car, our dogs runs tot he door, expectantly. When any other car comes in the driveway, he sounds an alarm. The dog recognizes the pitch of the engine.  >> Our dog does the same thing, although I never thought of it as a pitch recognition phenomenon.   It could be a squeak or some other sound that accompanies the engine, inaudible to us.  Or it could be the "way" we pull into our driveways.  I know I pull in at the same speed every time, same braking rate, creating a pitch envelope which might create a signature sound identifiable to the dog independent of actual pitch recognition.  Then again...maybe he does have perfect pitch.   Tom S.</BLOCKQUOTE> It's not so much the pitch as the *whole* sound as Virgil Smith suggests.  I distinctly recall as a boy in Los Angeles, that I had a Los Angeles Times paper route which required me to be up and working at 5 AM.  I lived in a residential area and at that time of day, the city noise was at its lowest.   I could hear the boss's car coming when it was a mile away. It was a Ford which had a distinctive sound and just like pianos, each one still has its own sound that anyone and also household pets can recognize.   My Dad always bought Fords and if it was quiet at the moment, I could hear his car driving up when he was coming home too.  I remember a distinctive whine from the engine, gears and drive train from all the many miles I rode in our Ford station wagon on family trips. I've owned other makes but currently I have a year 2000 Ford that has a 5 speed manual transmission.  That distinctive sound is still there!  It is one of the best cars I have ever owned. I don't have any dogs but I have two cats who react to sounds rather predictably.  They always know when I am coming to the door and are there to greet me.  I don't have to call them to be fed, they know I am getting their food for them just by the sounds I make doing so.   Blind people have to rely on all of the other senses.  That is why they are often believed to have "superior" hearing.  They don't really, they have just learned to use and focus on the aural stimuli more than the average person. Household pets and other animals probably do use their sense of smell and hearing in a far more sensitive and developed way than humans do.  I don't find it surprising that animals react to certain sounds at all, I more or less expect it.  I do, however, still find these anecdotes amusing. In my early days of aural tuning, I had learned from George Defebaugh to tune the octaves wide or sharp during a pitch raise.  One of my earliest experiences trying this newfound technique caused the big mastiff type dog that was in the house to howl.  For quite a while thereafter, I had the idea that in a pitch raise tuning, the amount to tune sharp was whatever it took to make a dog howl.   It worked then and although somewhat refined, still does now. Bill Bremmer RPT Madison, Wisconsin</HTML>