Drop off some samples Ashley and lets discuss them. 

First lets establish the ground rules. when we are looking for hard bop, we have two things in mind:

1) The blues (or gospel), especially minor key blues.

2) straight ahead driving rhythm, usually swing based, but not always.

This cut provided, "Early Summer" is a tough one and a good choice.

As you know, the album that this comes from, "Scenery" is tagged Hard Bop, but this track is a little different.

The album tag remains hard bop, and some would tag this song as hard bop, but I would tag this song as post bop, although it is not a clear case.

Harmonically speaking this is 'modal jazz', in other words they are jamming in one key, or mode (G Dorian) instead of following chord progressions. Modal does not determine genre as post bop, hard bop or fusion tracks can all be modal. Still, I don't hear much blues here, so I would tag the song post bop, but it could be tagged hard bop too, and not be way off.

On a side note, there are some interesting hybrid rhythms here, which is often the case in Japanese jazz. This piece does not actually 'swing' in the way we would normally think of swing rhythm, which could also push its tag towards fusion, but still post bop remains the best compromise.

This track is a good example of how difficult genre tags can be. 

Re arrangements: The presence of arrangements is crucial to both big band genres and 3rd stream, but otherwise it is not part of any other genre definition.

Hard bop, post bop and fusion can all have complicated arrangements.

This one feels like Hard Bop without being particularly 'driving' but I wonder if there's anything else going on that I can't pick up on as a non-musician? For instance, Empyrean Isles is a Post Bop album of course, and I considered posting One Finger Snap instead, as a clear Hard Bop piece, but thought that Oliloqui Valley might be worth a look too?

To me, that's hard bop that is leaning towards post bop.

The 'whole new thing' thats happening on this cut is all the time changes or 'metric modulations', the brilliant drummer Roy Haynes could move all over the place and still swing. 

In today's world, that cut could be tagged 21st Century Modern, this album, along with a lot of things by Dolphy's running mates like Mingus and Chico Hamilton, could be considered forerunners of today's jazz.

This cut could be used as a text book example of post bop, the rhythm swings, but in a sort of fractured way, the chord changes are abstract with the extended harmonies etc., plus a 3/4 feel a lot of times. The drummer favors Tony Williams for sure.

Hello! I don't mean to insert myself into an old thread but I remembered looking at this thread when it was made and not having any input at the time.

But now I have a question! Speaking of the line between hard bop and post bop, I'd like to approach from the other side and see where the line between post bop and avant-garde/free jazz is.

Paul Bley's album "Paul Bley with Gary Peacock" is listed as avant-garde jazz on here and I was wondering how it got that designation as I would have personally placed it in the post bop area of things. It's not a straight forward album by any means, but it's definitely not as free as many other ECM albums are.

https://www.youtube.com/watch?v=Vk9_bByHCNo

"A Love Supreme" was considered more or less avant-garde way back when.

https://www.youtube.com/watch?v=4rMiD8UUcd0

I left "This is Our Music" as AG, the album opens with a hard bop number, but then they get outside after that, and more or less stay there, although the self recorded cassette I have seems to be missing a few tracks towards the end.

No problem, I'll check it out, we want to have correct genre tags. I'm in this for the long haul. 

RE Sam Rivers album, just listened to samples on allmusic and amazon and it seems Post Bop would be a good fit. Allmusic describes the album as being in between post bop and AG.

You might enjoy checking out this thread:

http://www.jazzmusicarchives.com/forum/forum_posts.asp?TID=4648&PID=58108" rel="nofollow - http://www.jazzmusicarchives.com/forum/forum_posts.asp?TID=4648&PID=58108

By the way, I don't get the cover for that album.

Oh wow, until this very moment I always just assumed it was him standing on a ship's mast or something. Upon closer examination... I'm not sure if that's him or not. And it looks like he's standing in front of some antennas?

Some of these albums by the 'young lions' of the 90s up to recently are always right in between hard and post bop. I listened to some albums over and over trying to get a decision, its not easy sometimes.

Then there are those people like Coleman Hawkins who are right in between swing and bop, or Monk who is right in between bop and hard bop, etc.

While we're at it, how does one differentiate between 'Bop' and 'Hard bop' and is 'Bebop' = 'Bop'?

Hard bop is more modal, often based around minor blues chord changes.

In bebop the harmonies move and change faster, while in hard bop they are more apt to stay on chords where the harmony stays the same.

In other words a bop player is having to change the scales he is playing faster than the hard bop player.

Also, early bebop tends to use faster tempos than hard bop, but not always.

Its that functional harmony that makes bop sound 'old fashioned' to modern ears. Todays music, from metal to hip hop and almost everything else is based around the sound of minor blues, Chicago blues actually.

To that I would add that some bebop was based around minor blues changes as well.

That's very interesting, thank you for going through that for me. Didn't realize there was a tonal explanation for why old pop music sounds the way it does. 

I took Music Theory I (for majors) in college, but I'm no expert. I try to keep up with chord progressions when they seem important but I'm more than happy to just listen passively haha. That said, I mainly try to rely on instinct when it comes to identifying interesting chords/harmonies/etc.

It does not take any knowledge of music theory to hear the difference between bop and post or hard bop, they just sound obviously different.

Here's an album that is in line with the original intent of this thread: Sound of Sonny // Sonny Rollins. That's an interesting album, but I don't know that I would have called it Post Bop myself. The unaccompanied track is off beat, but is it that far out there?