I both liked and was kinda "eh" about this one.
He used the word "queer" fifteen times - I know, I know, it meant something different back then. That's not the issue. I just wish he'd nabbed a thesaurus before launching into descriptions of how odd and preternatural that room seemed, instead of saying there was something queer about it so often. It's a decent enough adjective, but not very specific.
The references to the earlier adventures also seemed a little odd to me, because of the tone. "Why, it was there I found the Red Mask, propped against my bedstand in much the same manner as the Spear of the Ancients from my excursion to Spain, as-you-well-know." He's consistently redundant in this way, not alluding to past adventures that the Hodgson fan can knowingly smile at, but rather kind of hinting with a cudgel.
I did like that he states that a large number of his cases wind up a wash, magically speaking, and the hauntings he's sent to look into are bunkum. I'm not against a down the rabbithole mentality about the supernatural, where everything's off once you know where to look. I liked Neverwhere and the Dresden Files (and the hundreds of other fantasy works that use this). But I really felt that Hodgson's approach of including the rational world into his investigative approach was novel, pretty effin' brilliant, and sadly underused nowadays.
Another thing that I found a little "eh" was the lack of strong characters. The rollicking pacing kept this story moving, and the author was pretty able in that department I think - no mind wandering from me, I think it was going at a good clip the whole way. But I realized just how badly he'd floundered the characters when I went to write this big ole, clearly blowhard-y and overlong review... I couldn't remember the name of anyone besides Carnacki, nor the physical description of even one of 'em. I knew that Tassoc (I had to look him up) enjoyed a belt of liquor or three, but that's about it. The characters just didn't come alive for me at all.
I very much liked the story for the reveal at the end about the source of the whistling, its overall snappy conversational tone that very much recalled to me Dupin and Holmes, and the eerie ambiance the story establishes.
I also really liked how after recounting a magical principle to the narrator, he ends with "Am I clear?" As heard by a modern dude, it seemed offensive, but I think Carnacki's brusqueness was maybe less discourteous back in the day, when men were men and women were cleaning.
The reading was good, and I'm sorry I don't have more to say on it after writing so much about the story itself. Heckuva good job.
I swear, I did like it, I just wish we could've summoned Hodgson's ghost to tighten this up for a modern audience.