# Introduction To Audio Technology, maybe helpful

I changed the mathematical parts again. I hope I did not produce new errors in the process.

I am too late, it seems, but you could do the query-replace-regex with search _{$$[A-Za-z][A-Za-z]*$$} and replace _{\\text{\1}}. This would match at least one letter at the very beginning of the subscript. (For at least two letters, use _{$$[A-Za-z][A-Za-z][A-Za-z]*$$}.)

I took a quick look at formulas and it looks good to me. A couple of things only (since you said you don’t mind nitpicking):

• You should only use _{\text{...}} if the subscript is text, like P_{\text{ref}}. But, if it is a number or variable, like p_1 or p_i or p_N (where N is the number of terms – like in formula 2.16), do not use text. (i and N are like variables, so need the italic.)

• On formula 4.7 you forgot the \ for \sin.

• On formulas 4.42-44, I’d use \text again for Cardioid, Ominidirectional, etc., since those are not variables (I assume).

• This is very minor, but I would add some spacing (with \,) in formulas that get crowded, like 2.14 and 2.15. (Like \sqrt{2} \, p_{\text{eff}} \, \sin...).

• If the formula gets too long for a line (maybe after adding spaces), you can use the align or multiline environments . (It might need the package amsmath.) See: https://www.overleaf.com/learn/latex/Aligning_equations_with_amsmath

But it’s looking really good. I hope I can actually read it sometime.

For the last proposed improvement I will need some time to go through the document and check visually where it is needed. I will not do that right away.

I have tried to fix the other points in a consistent way.

Yes, the formula do look better this way.

I changed Formulas 4.42-4.44 to say more precisely what is done: the signals are added or substracted. So: signal_{\textrm{cardioid}} = …

If someone here is interested in surround recordings, I just added two paragraphs about ORTF surround and ORTF-3D, very promising microphone assemblies to record surround atmospheres with a very compact setup.

I still have problems displaying the document. All my tools (except one) complain that it is corrupted.
mutool (from the mupdf package) is able to repair the file so it can be viewed with all tools again.

What tools are used to create this document?

Same here - I haven’t been able to open it in anything other than Chrome on Windows. I think what this highlights (albeit tangentially) is that this is probably absolutely the wrong way to do this.
I don’t want to be discouraging of the author’s efforts (I’ve written technical documentation in a professional capacity, so I appreciate exactly how much work is required and how difficult it is) but, there is a danger that this will just become more ‘background noise’. Or at best another well intentioned but contradictory addition to every other ‘how to’ audio guide out there already. Its very similar to the “proliferation of standards” - which I have highlighted before and is beautifully summed up here:
https://xkcd.com/927/
For something that is just intended to be general useful information (not to promote a particular product feature for example) then perhaps some kind of wiki article is better?

I like to be able to read documents like this in a convenient manner. I’m a bit old fashioned and have bad eyesight, so a simple linear document that I can read with my preferred reader is what I prefer over web documents and wikis.

For example, one of the other documents mentioned (Curriculum - Digital Sound & Music) I can only read online, and I am not always online. I cannot download it to my tablet.

This is personal, of course.

You can normally download (for example wikipedia) articles as PDFs - that might also have the side-effect of allowing the author to indirectly create a PDF that opens in more reader applications too.

For the record, the book can also be purchased. The intent of what i linked to above was to create an open curriculum (Yes they accept updates submitted to them, sadly no easy way to submit a pull request to update for instance the information on audio on linux, I need to get back with them for that at some point) for others to use, so the contents of it are available on the website as well (Can’t remember if it is the full contents or not, but likely is) and was more of a counter example of what an introductory text could be.

But I think Mike has likely hit it on the head.

I would love for this not to be the case for the record.

  Seablade