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

Not kidding. You can't get realism in slam without playing it near the levels you hear it at live. Bring a sound level meter to live events, you won't believe the SPL peaks.

I'm not advocating playing at those levels constantly at home. But, if you want to see if your system can have the slam of a drum like you heard it live you have to play it back at that level. Then you will know if the perceived lack of slam is due to your system or just the fact that you are playing it much lower than real life.

Course, that assumes you want a system to sound real. My experience is that most audiophiles don't go hear live music and are just chasing some idea of what they think it should sound like.

I agree with Martykl. My experience coincides with his. I do feel slam is a real part of some live music. I like a system that can give a credible rendition of slam.

An example would be really hearing the "kick" in the kick drum.

Yes, you feel the wave hit your body with a nice kick drum shot when you are near it, with no amplification. I would call that "slam". Same with the floor tom, which is actually a lower frequency than a kick drum.

During the recent "great recession", I spent most of my time over on the prosound side of things. Imo, there's a lot of validity to Mtrot's observation: "I'm beginning to think the ability of speakers to achieve that sense of dynamic "liveness" may be as or more important to a sense of realism than frequency response accuracy."

On the acoustics side, I take the word to mean unrestrained dynamic transients. Compression can come from amplifier clipping or loudspeaker thermal or mechanical limitations. I believe that the most common culprit in loudspeakers is "thermal modulation", a quick-onset compression that results from the near-instantaneous heating of the voice coil from a high-power transient.

On the psychoacoustics side, "slam" registers when a limbic system response ("fight or flight" startle) is triggered. It is a function of transient dynamics and raw SPL. If there's not much dynamic contrast, it doesn't come across as "slam". If there's good dynamic contrast but the sound pressure level is still soft, it doesn't come across as "slam".

From a loudspeaker design perspective, the solutions include high efficiency and/or large diameter (or multiple) voice coils. If a loudspeaker system is being pushed close to its RMS thermal rating on peaks, your peaks are softened and so is the emotion conveyed. If a loudspeaker system is just loafing along at fairly high SPL, it will deliver plenty of slam. That's why 5 watts into a 98 dB efficient speaker almost always sounds so much more lively than 200 watts into an 82 dB efficient speaker, even though "on paper" both are 105 dB capable.

Duke
dealer/manufacturer

Mr K- Like I said......