I was referring more to the tutorial examples, rather than the theory sections.I would argue--and this is my perspective that I fully understand you may disagree with--that the principles in the book can be applied to most synthesizers out there. Look at the chapters: they cover envelopes, filters, oscillators, modulation, and frequency modulation. These are all pretty universal concepts that apply to most synthesizers.
Well, just keep in mind as you read my response, that what I say obviously shouldn't be construed as anything authoritative or completely practical, which I'm sure you're fully aware of. I'm just not that qualified. Also, as my problems stemmed from the tutorials and examples, that's what I'll focus on, as the theory was executed as well as it could be. They are my problems to deal with, but, as someone who's in your target market for these books, it's worth addressing.I'm serious about this. When writing about sound, I don't understand how you can write about anything other than specifics. To write about generalities--especially when you are talking about something as abstract as sound--is to make the topic applicable to no one. How can a book that is applicable to no synthesizer on the market be more applicable than one that is applicable to the five most popular synthesizers on the market (at the time of writing)?
As I say, this is a serious issue for me. I've mentioned my next synthesizer book (http://noisesculpture.com/synthwiz.html) and I'm keen to incorporate any feedback from my previous books. As you have seen, I did incorporate people's comments when there was the (correct) view that I had excluded Macs.
I have another very real and very practical difficulty where I would like your input: each specific synthesizer sounds different. Try it for yourself: get three synthesizers from three different manufacturers and set up a patch where you run a sawtooth wave into a 24 dB filter and modulate the filter with an envelope.
Then try and get EXACTLY the same sound on all three synthesizers. To my mind if you can't hear sonic differences, then you need to check your ears.
If you can't create a sound that can be replicated completely on any synthesizer, then how do you describe it in a book? How does the reader know when they are hearing the sound as you intended? The job is already tough enough to explain in words how to create a sound on a specific synth--if you move a knob or two by a few percent, you can make a huge difference to the sound?
As in "How to make a noise", the theory can be written and explained, with helpful diagrams and such. I'm sure that's a given.
As for describing and teaching sounds, I think you have the right idea about having sound files included with the book as a reference. But this time, the sound files could possibly coinciding with each step you give in the tutorial. Emphasize the differences between synthesizers and that your sound examples are meant to be as general as can be and do not sound like synth xyz, just so that other users are aware of the differences. You could include the name of the synthesizer you're using in case readers want to duplicate what you do to a pin point, with the synth being mac and PC compatible, though you've already addressed that.
If you had a small sound file for each step in your tutorial, even if everyone is using a different synthesizer, they'll at least be able to hear the difference in YOUR example. They can hear the effect a 24db filter makes on a sawtooth, how the tuning affects the pitch, etc. etc. . I feel like even if you were using a different synthesizer, if one could hear the difference between each step, and at the same time read an explanation on why that difference is happening, then they would better make the connections in their head. "Ok, reducing the cutoff takes away higher frequencies". These connections would be easy to transfer between any synthesizer, as the reader would have an auditory, as well as abstract, idea in their mind as to how doing x does y. They would know what stimulus has which response in terms of sound. Additionally, if you were maybe to give narration during these step sound files, like "Now I'm changing xx, hear how yy is affected?", as an added reference for the readers, could be helpful.
I realize this is essentially holding the reader's hand through nearly everything and that these methods would probably be difficult to apply to more advanced techniques and theories. However, for beginners, it could be a very useful tool. With something like synthesizers, which is so dependent on sound, it would at least provide another angle to aid in the learning process. People tend to excel in learning either by hearing new information, by seeing it, or by actually getting hands on. I think this approach could manage to handle each of these learning styles. I know my learning style, a combination of hearing and hands-on, struggled with your last book because I got frustrated without being able to hear what was supposed to be happening while being hands-on with the synthesizers I have. Though that's specific to me, it's worth noting. Also, I know a lot of people buy a synth first and learn it second, so to have tutorials that could be done by most synthesizers would help. But, as I said, the drawback is that some synths may not have certain options. I'm not entirely sure how to deal with that. But, a lot of the same principles are universal in sound design regardless of which synth is being used (though synthesis types can't be taught as universal).
Now, I imagine that the sound file idea could be costly and difficult to implement. I'm not familiar with the process you would go through to implement these ideas if you ever considered them. However, as I said, this is purely speculation, I'm not knowledgeable enough to say how practical these ideas would work in the context of your goals, constraints, and vision.
Also, I should of said this earlier, but my first post was made when I was feeling frustrated, so I was a bit harsher and judgemental than necessary. However, those were my exact feelings at the time and they were conveyed in full. So for the purposes of feedback and insight from customers on your book, it's just one more user's experience, this time more negative than others.
Synthesis is a difficult subject to learn just because nothing is standard in the world of synthesizers aside from the theory behind sound design. People are kind of forced to jump in and learn on their own, usually after having bought a synth. While manuals are always useful tools, they don't offer comprehensive information on the theory of how synths work and the principles of sound design. Books that teach this are important, so I hope that you continue your effort to provide a means of teaching this stuff to new users. It's a very open market for a practical, effective, and approachable book on synthesis. If you were to make the right book, it could essentially become the standard, as no-one has really established their book as THE book to buy and learn from. I hope everything I've posted helps in some way,
... IM(H)O this is a very clear case of what's described in this particular ebook: 
... arkaic..
