I'm digging in pure data/audio examples/g08 reverb patch and found one strange thing, delay times is 71.9345, 86.7545 and so on. Does this numbers calculated? If yes , how to calculate it?

very good question.

my guess is that reverbs mimic the effect of a room's floor, roof and walls, so the delay times correspond to that.

Good delay times in a reverb design are relatively coprime (no common divisors)
But that's an academic point. For a 'real' reverb they might have been measured, from an impulse reponse of the early reflections of a favourite place like a church or hall.

yep, convolution reverb are really the copy of an ambience in frequency, decay time T60, and pre-delay or early reflections.
if you want to calculate it you ned a gun (better a fake one) and a mike, then shoot and record. take a deep look at the waveform and look how many msecs pass among the direct sound and the start of the reverb.
This is impuse response (only for E.R.).

Obi, are you sure? I thought this was a rule to build rooms with good acoustic properties, but early reflections depend on where the sound source is in the room: how far from walls is (that can be totally random, or depending on the ensemble, or the stereo image you want to create)

anyway, theese are only academic problems. the only point is:
are your hearing satisfied?

ciao

For convolution reverb check out Ben Saylor's [partconv~]. It's in PD-Extended under

5.references->bsaylor->partconf~-help.pd

cian.ltdt , in your example would it be possible to use a close-range dynamic mic (sm57 comes to mind cause of it's prevalence) and flip the phase of it to pull out the original 'bang' of the shot out of the mic picking up the reflections?

I think this is the way.
I'm in doubt with dynamic microphones, condensers usually have a frequency and transient response more accurate, so the room is picked up in a better way,
but you can try (tell me how is working...)

A gun's a bit much, isn't it? I've seen people do this by popping balloons or using short noise bursts (though you would ideally use something like a dodecahedral speaker for that). I wouldn't want to close mic a gun, unless you don't mind having your mic die out quicker. I was also under the impression that using these type of short impulses with such wide spectra was so you didn't have to worry about taking them out of the impulse response. I might be wrong about that, though.