Greetings, and welcome to another "Curious Names" article. This one will be quite short and sweet---well, short.
I was recently astonished to find out there are some people who think the romanization "Aḥmad" is wrong, and the name should be romanized "Ahmad". This is not because they disagree with the romanization method(s) as such, but because they think the name is properly pronounced with an "ordinary h"; that is, with a sound similar to the "h" found in the English word "hot" (to be exact, the ه , the "h", is pronounced deeper in the throat than in English).
What these these folk do, is deny that Aḥmad uses the ح, the "ḥ", which is similar to the ه, the "h", but with a restricted airflow. In other words, one could say, ح is a "roughened" form of ه.
I do not know on what basis they can make this claim. The name Aḥmad is well attested in Arabic literature, and is always spelled with the ح. Further, the name Aḥmad is based on the same triliteral root as Muḥammad, and I know no-one who pronounces that with a ه, a "h". I have to guess that in some modern dialect, the ح, the "ḥ", has become softened to the ه, the "h". Or, perhaps, the those folks are using a pronunciation from an area where Arabic is not the native language¹.
But we who seek to re-create Islamdom in the middle ages cannot depend on modern dialects. We must, (well, we should) seek to find the period pronunciations. And, the the case of Aḥmad, the ح, the "ḥ", should be used.
So, learn how to roughen your "h"s into "ḥ"s, and say "Aḥmad is great!" along with me. :-)
¹ With the spread of Islam, a number of names of Arabic origin became popular in areas where Arabic wasn't the native language. In such cases, the pronunciation may have shifted. I mention this not to belittle such a pronunciation, but to show one must be careful using Arabic-origin names from areas where Arabic is not native, in documenting pronunciation.
Sources:
The Qurʼān Sūra 61, Āya 6.
The Encyclopaedia of Islam, 2nd Edition; there are a huge number of "Aḥmad"s cited in this work; the only "Ahmad"s are post-Medieval and from areas where Arabic is not native. See my note ¹ above.
The Encyclopaedia Iranica, online. Out of the first 100 "hits," there are only three Ahmad No-Dots, and two are placenames outside of Arabic-speaking regions. The only person is both from outside of Arabic-speaking regions, and post-Medieval/Renaissance.