The sounds that you hear where you are making them aren't the same as they sound out at a distance it's like when you hear yourself talking then listen to a recording of yourself talking. The sound chamber does change the sound and makes it a more mellow sound, the use of your hands has a different tone, just as the wearing of gloves tends to deaden the tone if you are using your hands, wooden sound horns make different tones depending on their length as well as the type of wood and their shape does. Plastic makes a different sound than a cow horn does. The plastic hose for your elk bugle, that has ribs in it sounds different than one without them. It is designed for you to be able to project your sounds in different directions and change the tone to raise or lower pitches saying I'm an older bull or a younger bull. I want the herd bull to think I am farther out then I really am, so he comes closer for my shot with a bow ect. Yes, it's all in the playing with and figuring out what I need to with each type of call, how much air flow, hard puffs, long drawn-out air flow, how do I place my hands, with or without the sound chamber. The same as with the sounds that your coyotes make in your area, I can only give you the basics and it's up to you to get it to work for you and your coyotes. That is part of the enjoyment of the pursuit of coyotes learning what does and doesn't work for me, taking what works for him in his area and adapting it to work for me in my area. No matter what I can only give you what works for me the best that I can explain it and then you will take that information and adjust it for what works for you as it should be done for us all. For me in your situation yesterday I would have done a couple of my voice barks to see how the coyote reacted to them because that's what works for me to get them to stop and stand for a shot when I'm calling, just a woof at them in my own voice, it's what I learned by doing it over time and visiting with others that had more time doing it than I and then the adrenalin rush of it working making an imprint in my mind for future references. One more tool in my box learned out of necessity that others may be able to put to use as well.