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

I put this question under speakers because I assume "slam" is mostly a function of the speakers, but perhaps a certain level of amplification is required. The only places I have experienced slam is listening to certain demos at audio shops, and some live music. Most speaker demos I have heard over the years did not produce slam.

So, what mostly accounts for a system producing that "slam" you can feel in your chest? Is it that certain speakers are "voiced" with a mid-bass hump that causes it? Do they EQ the signal to produce it? Do they employ super powerful amps?

Secondly, how accurate is slam? How much of a goal in speaker selection should the ability to produce slam be?

The reason for the questions is that I am getting close to being in the market for new main speakers. My current amp is a McCormack DNA 1, BTW. Thanks for any info!


mtrot
bjesien
1,283 posts
 

Have you been sitting on this one?

I'll add well made enclosures.

jon_5912
604 posts
 

Big drivers in a big box.  The bass drivers need to have a high cutoff.  A big subwoofer with stand mounts can play 20hz-20khz but won't have slam.  The surface area of the woofer is the key.  

phusis's avatar
phusis
1,197 posts
 

Duke put it excellently into words:

”… 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“

mahlman
433 posts
 

I guess when you talk about slam with main speakers you are referring to not only audible but also a physical sense of sound waves hitting you. In my experience the best slam means if I want to listen to drums or say fireworks that there can be a sensation of a sound wave passing you like it would be in real life. It hits you quickly and does not suffer from a buildup to reach peak levels as would happen with having to push a driver to hard to get there or having to much excursion required to get there.

  I am working on a two way system right now and it has two 12" woofers in the box. I have been a 15" woofer guy for a few years and now lean towards 12". I think the cone size being smaller delivers sound faster and with less cone flex and is therefor punchier and has better resolution. The efficiency on them is 99.5db and 400 watts each and as @phusis  says when your speaker just loafs along to get the sound levels you want it does so with superb definition if all was picked and assembled right.

 

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