"Slam"--what is it, is it really accurate?

Martykl, I agree, but please excuse me if I seem petty, but "slam" to me is also a reproduction of transient bass macro-dynamics. Yes, it is accurate; if it's on the recording, it should be able to be reproduced in your room.

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I get plenty of slam in my system. But the funny thing is I don't ever recall hearing any slam at any of the live music that I've ever attended.

No doubt slam is a more common element mixed into many (not just pop/hip/hop/electronic genre) more modern recordings, many of which sound very good, but only when the playback is up to the task.

Its noticeable in most well recorded CD from mid 90's on. That's about the time where I have read some fundamental standard EQ changes (for the better) were implemented in teh recording industry. ALso coresponds with the start of teh infamous "loudness wars". These days CDs are much louder (hence more "slam") so the game has changed. OF course many pop recordings targeting getting attention from the masses are overdone and are sonic atrocities in many ways, but many more are not and done quite well albeit at louder levels overall on average than in early years of CD.

So this gives recordings a bias towards "more slam" compared to many live experiences, but that'snot to say slam does not occur in live performances both acoustic and electronic as well, as noted above.

"Inefficient" systems will have more trouble delivering louder recordings with more slam well in general. EIther more efficient amps, more efficient speakers, or perhaps even both are the tickets to getting to a good place in regards to a playback system being able to deliver all the goods in any recording, for better or for worse.

Luckily, I am finding more sonically great moments when I listen to recorded music these days than ever before in my 50+ years, in recordings of all types both old and new. So hopefully, that is a good omen in general.

"Slam" done well has always been a sell point for many of the best "audiophile" recordings over the years.

Nowadays, its a lot more common, for better and for worse, and not so novel. You do not have to buy a special "audiophile" recordings in many cases to get it done well. Off course it is also often "overdone" as a selling point as mentioned. THat's entertainment! Nothing new there with teh entertainment industry overdoing something and even beating it to death regularly.

Performance dynamics are the door to "slam." (inadvertent pun alert) System capabilities aside, if performers are capable or even aware of dynamic contrast they can use it as a tool to get more mojo and emotional impact from the music. I don't like much monodynamic music, which a lot of popular stuff turns seems to be. Without space and some dynamic breathing it just sounds like yelling or something you need when hammered in a Euro disco at 4 AM. When I first saw Led Zeppelin in 1969, the technology available for PA systems (usually a pile of Altec A7s) wasn't allowing the ear splitting levels that soon (very soon) became the norm, but good ol' Zep cleverly used the dynamics of soft and loud to make it all more powerful, and it just seemed loud and good. I can't listen to Arcade Fire or Black Keys or most other modern pop stuff for this and other "geezer based taste" reasons, as many musicians and producers are clueless (or lack the desire to care) about dynamics, without which "slam" becomes "drone-like thumping" and sends me back to jazz.

Audiophile axiom - It's a lot easier to get slam in a headphone system than it is in a speaker system.