"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!

Buy and large for me "SLAM" is a HiFi or pro-audio support thing. What I mean is, very little acoustic live music ever produces real "SLAM" unless it is of an electrified genre. That said, I think it is a matter of taste for the music reproduction listener and yes it is a matter of amp AND speaker synergy to produce the physical wallop you desire. For me, that characteristic is way down the list of sonic requirements, below timbre, tone colour, texture, and transparency, just to name a few. But I don't mean to rain on your parade, if that is a compelling element to you at this point.I would only caution that to accomplish this, you may well compromise other more subtle aspects that could prove to be more satisfying in the overall context of a musical performance (even in a hard rock type format).

Happy Listening!
"Slam" sells , meaning people tend to like it, and is a big part of many modern recordings these days, especially in pop and music realms involving synthesizers, etc.

It can occur naturally as anyone who has sat close and listened to a drum or any sort being played knows well.

Most forms of live music (save perhaps most forms of classical chamber music or perhaps acoustic folk) have a certain "slam" factor, that varies case by case. Proximity of listener to players usually is means more slam.

My opinion is that if the slam is in the recording, I want it to be delivered accurately along with the rest. Its a big part of being able to convince the listener that what is being heard is real and not just a recording, even though it is.

TO enable that, speakers must not be undersized for the target room, amp must be capable of driving speakers to the max, and a good quality source is needed.

THen the recording is enabled to do its thing, slam or otherwise.

YEah, I hate thumping bass with no texture or detail as much as the next audiophile worth their salt, but love it when done well.
Complete agreement with all Mapman's statements plus an aded emphasis on the importance of the listening room being part of the equation. I've gone through the evolution of DIY room treatments, discarding those and then adding GIK bass traps, and finally adding a Spatial Computer Black Hole pressure regulator in the search for accurate, well controlled bass. With each step, bass has become more accurate and the "slam" we're talking about has gotten more believable. Like Mapman, accurate, you-are-there bass reproduction is something I love.
I've been comparing headphones lately.

Good headphones, like many popular Sennheiser and Audio Technica models, deliver the slam well along with all the rest.

THose along the "Beats" track may deliver slam but not good sound all around.

Others, even some pricey popular ones, are simply junk and turn to jelly with any "slam" present in the recording. Bose headphones were the biggest offenders in this regard I have experienced recently.
"Slam" isn't exactly a well defined word, in
regards to audio. Similarly; some disagree when the term,
"tight" is used, in reference to accurate bass.
When you are referring to live music; one need not be very
close to a drum set, to feel the sensations with which the
kick, toms and snare(or timpani, in a classical setting) can
impact your senses. You can literally sense the tightness of
the skins, through your body. Ever been around any taiko
drummers or pipe organs? They'll fill a good sized venue
with tactile sensations, quite well. The bottom of a
B3, produced though a pair of Leslie 122's, can push a bit
too. Regarding audio reproduction: Mapman's last four
paragraphs(1st post) echo my views.
Slam means macro dynamics in the bass registers - at least in my book.

Walk into your local music shop and ask a salesperson to knock out four Beats on a kick drum. That's a good starting point to shoot for and can certainly be achieved in a good system without goosing FR. Good quality subwoofers (if crossed in high enough) are usually a good example. You're looking for high clean output capability between 50ish and 70ish hertz in most cases. Since most speakers don't spec this capability, you're mostly on your own in determining a full range speaker's ability to deliver "slam".

If you define the term more broadly (eg to include reproduction of a pipe organ) then the bass output capabilities must obviously extend well below the 50ish hz cited above. In all cases, you should be aware that many recordings - by design - will not provide the dynamics to allow full reproduction of bass macro dynamics.
For an easy and decent "quality bass/slam" demo, head down to BEst Buy or equivalent with your Iphone or equivalent and give the fairly new Sennheiser Momentum circumaural headphones ($300) a listen. These deliver a decent example of what good detailed bass with slam should sound like, even off a decent quality standard issue portable audio device sans any special amplification.
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.
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.
Audiophile axiom - It's a lot easier to get slam in a headphone system than it is in a speaker system.
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.
Thanks much for all the replies. I'd like to ask if you think my McCormack DNA-1 has the cojones to produce slam with reasonably efficient speakers? I think it is rated at 150 watts/channel into 8 ohms, and 300 watts into 4 ohms. My speakers are the(fairly old now) Legacy Audio Signature II, which are supposed to be very efficient, but I have never found them to produce significant slam on drum shots, or be all that dynamic on transients in general.

What I don't have a clue about is whether the Signatures are capable of slam/dynamics given a much more powerful amp, or if I would benefit more from a new/different set of main speakers. Any thoughts much appreciated.
"What I don't have a clue about is whether the Signatures are capable of slam/dynamics given a much more powerful amp"

Looking at specs of SE version of your Legacy speakers (can't find same for IIs), and assuming they are similar, I'd say, yes they should definitely be capable of "slam" in most rooms if in good working order.

I'd also say that given the power recommendation from Legacy for SE version, assuming similar to yours, of up to 300 watts, a bigger and beefier amp would yield additional dividends in the slam department.

Most vendors underrate the maaximum power handling of their speakers in order to play it safe and so as not to scare off buyers, but in general, I would tend to throw the kitchen sink amp power wise at speakers like those. A good quality 500 w/ch into 8 ohm Class D amp is what I would try. I landed on mine for my big OHM speakers for exactly the same reason. 250 w/ch Class D should deliver nice dividends as well.

I use my 500w/ch Class D amp even with my tiny similarly efficient Triangle Titus monitors, along with all my larger and more power hungry models.

As long as you listen to your ears for any signs of stress or breakup with more challenging recordings at a particular volume before going louder, you are not likely to damage most good quality speakers that are in good condition.

Your more likely to damage a speaker by blowing a tweeter if you attempt to crank up an underpowered amp too high and clipping occurs.

More power keeps clipping out of the equation. That creates dynamics and slam and is also easier for most good speakers to digest to boot.
@ Mapman,

Thanks much for the thoughts. Just for grins, could you name a starting point in the way of a class D amp? It would be interesting to compare a state of the art class D amp to my McCormack DNA-1 rev. A. And even if I were to find an increase in slam/dynamics with the class D, I would want to make very sure that I did not lose any of the mid and high frequency "niceness" that this McCormack has.
Lots of info here on various threads regarding Class D amps.

I've been using Bel Canto ref1000m monoblocks for a few years now and think those to be rock solid still and a very good value used. That's really the only ones I can vouch for based on extended listening. I've heard other good ones as well in recent years from Jeff Roland and Audio Research. Other that would be of interest for me due to value potential would include Wyred4Sound and DSonic. I would probably avoid older Class D amps in order to access current possibilities in that the technology continues to advance significantly still.
Hypex Ncore technology has really upped the performance standard for Class D. I have a pair of monoblocks for sale right now here on Audiogon if you're interested.

But I would caution that amp power, while important to deliver slam, is not the only precondition. You also need clean and dynamic source electronics capable of driving the amps well. Since slam is about dynamics, if you don't have high resolution and low noise signal, it will blur the dynamics and detract from the slam. We are always fighting some level of dynamic constriction in recordings, some worse than others with the loudness wars, but even really well recorded stuff is much less dynamic than real life. Such is the nature of recording vs live. In order to maximize dynamics, the entire signal chain needs to be clean and clear, and electronics need to have good impedance matching with each other so they aren't strained and have enough "drive" to create that realistic slam. A good preamp is often key to giving that last bit of drive and dynamics to the music.

I also think clean power into all electronics is highly critical. Good in restrictive power conditioning like the Pi Audio units and power cables that do a good job of rejecting and filtering noise can really reduce the noise floor of your system, which in turn increases dynamic contrasts and slam. Of course it also greatly improves imaging, soundstage, and micro dynamics as well, so it's not either/or when it comes to slam and other audiophile characteristics.

Finally, I would say proper management of bass resonance and nulls in your room are vital to slam in the bass frequencies. Untreated rooms are a horror show of bass anomalies that produces varying levels of boom and suck out at different frequencies. If you can use room treatment, multiple subs in a distributed array, EQ, and/ or combinations of these to even out the room response, your system will be capable of producing clean and even bass that will then slam rather than booming.
@ Genjamon,

Thanks for the informative reply! While I have no doubt that your points about certain aspects of electronics are factors in production of "slam", I must note that some of the demos where I have heard and felt "slam" have been at very much mid-fi retailers, who I am confident were not employing any sophisticated, high end pre-amps and/or amps. No doubt, the amps they used in such demos were likely very powerful, but my guess is that the biggest factor in the demos I heard was the speaker being used.

With my limited financial resources, I would be looking for the most practical, affordable way to achieve the most uncompressed, and dynamic presentation. Hence my question about whether "slam" would be mostly a function of speakers or amplification.
If the speaker cannot "slam", no amp will help. The speaker is more important in the slam equation than the amp. There are lots of amps that will make a capable speaker produce slam, but few speakers that have the dynamics to do it.

Anyone who thinks that it is an audio thing does not get out to hear live music much. Even a small drum kit can smack you hard. Course, most audiophiles don't go out to live music, they just talk like they do.
Slam is when you have a speaker on stands and your grandchild runs a football route into one of your speakers and it gets knock up against a wall like body check in hockey. It is very accurate and I hope it never happens again.
Slam can startle and slam can be subtle. It doesn't take much for certain notes to energize a room so it's not all in the purview of bass notes and loudness (volume). It's only because bass and loudness have been the topic of many a discussion when it comes to slam that that is what most folk think of when it's mentioned.

Having said that, I believe it's the speaker that delivers the goods.

All the best,
Alright, so maybe we're talking about different things when it comes to slam. For me, it's about when a solid bass note comes out of nowhere and you can both hear and feel it in a gutteral way. In my experience, it takes removing room resonance, electronic overhang, and noise out of the equation for those bass frequencies to be fully resolved and to have the fullest aesthetic impact. However, I also acknowledge that you can get there by leveraging uneven bass response in speakers, untreated room loading, and other "inaccurate" characteristics to make bass kick pretty hard. But in this case, you'll be trading in many other important aspects of the sound in order to maximize that bass impact.

Like others have mentioned, speaker design will play a big part. Ported speakers in general will "bump" more than other designs due to the resonant frequency of the port emphasizing at that frequency. It's not a completely even response, but it does give you that sense of drive and bass dynamics. That can be pretty fun if done well.
It's the room before the rest. Then it is the proper pairing of speakers and amp.

Case in point, when I first moved into my room, my system sounded fine but the bass response was not very good. I added treatments installed a proper rack dialed in the speaker position and then voila, Slam!

My system is nothing outrageous but I think that I am fortunate to have found a good synergy between all my components.

My slam test reference recording is the overture to Verdi's Rigoletto, the London Symphony Orchestra with Bonynge conducting, London FFRR OSA13105.
I don't believe "slam" can be accurate unless you have the very best components and a very tweaked(professionally) listening room. Even with great speakers that i've heard several times... IRS-Omega/KEF 207 I felt the "slam" was compacted and slightly over exaggerated when compared to live music? Maybe a super system with Wilson Grand Slams or an Infinity IRS ect. are needed to accurately reproduce slam. I think we need to hear from Albert Porter or Mike Lavigne regarding this topic.
The recording as much as anything else will determine how the "slam" goes down, track by by track.

More slam than ever in many modern recordings these days. Slam sells! Even good headphones like most Sennheiser phones these days do it VERY WELL!!!!

Home audio buffs: beware! Portable audio is cutting into that turf more and more these days (along with all the rest), so best to get it right and at an affordable price.
Slam to me is the ability of the system to reproduce soft to loud passages and back again. For an example, I use a track with two acoustic guitars. During a passage with both guitars strumming, one guitarist is wrapping his hand/knuckles ont he guitar. I was thinking about how hard could a person strum and wrap his hand on the guitar and how loud would and should that sound versus the rest of the instruments that were playing. In the beginning I thought wow that guitarist is really knocking on the guitar. Then I thought to myself, man that has to be a really close miked wrap or my system is not reproducing that correctly. I also play guitar so I used that as my comparison. I thought that was slam. When I switched to a more refined speakers that sound changed to less hit me in the gut sound and the wrap seemed to come more from the location of the one guitar, had less overall hit me in the gut impact, but it seemed to me that the "slam" was much more correct. The speakers were similar in design, both time aligned but the one pair had a more solid cabinet that the other which seemed to deaden the sound, some may call it having less of an impact or maybe even duller, (not as dynamic), but the more I listened the more I thought that the sound was more accurate. Kind of like first row presentation versus 15th row. The sound was fast and dynamic with the right amount of slam for what I thought could be reproduced by the wrapping of the hand on the guitar. So that is how I would define slam. How fast can the system go soft to loud and back again and retain the tone and resolution of the sound.

Happy Listening.
Slam is a description of bass performance, like crunch, best shown off with recordings of stream locomotives, atomic bomb tests, the T-Rex running in Jurassic Park, Mickey Hart drum recordings, soundtrack to The Terminator 2, things of that nature.
Its a catchy, marketing term that sounds a lot sexier than dynamics....which it essentially is...similiar to acronym PRAT...just clever verbage
Remember that in real life the SPL of individual drums being hit reasonably hard (slam would imply more than soft gentle drumwork) is going to be over 100db. Well over. Most speakers simply don't have the ability to convey music that loud without a lot of distortion. Most audiophile speakers just won't do it.
Kiddman wrote,

"Remember that in real life the SPL of individual drums being hit reasonably hard (slam would imply more than soft gentle drumwork) is going to be over 100db. Well over. Most speakers simply don't have the ability to convey music that loud without a lot of distortion. Most audiophile speakers just won't do it."

Kiddman, you must be kidding.
Also a term that became popular during the advent...of the HT era...iI dont hear it that much in audiophile circles....
Kiddman wrote:

"Remember that in real life the SPL of individual drums being hit reasonably hard (slam would imply more than soft gentle drumwork) is going to be over 100db. Well over. Most speakers simply don't have the ability to convey music that loud without a lot of distortion. Most audiophile speakers just won't do it."

So, could that be why some are drawn to large cabinet speakers with light, fast cones such as Daedalus? 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.
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.

Mr K- Like I said......
After I recently was at another audiogoner's house and saw him working with his banana connections in his setup, I decided to take a look at the bananas on my low frequency run. What I did was to pull a bit more of the cable through the connector and fold the entire cable over on one side of the connector.

What this resulted in was that upon screwing the banana ends back down, it was a much tighter connection and much harder to screw them all the way down. I did this at both the amp and speaker ends of the cables.

Lo and behold, after this free tweak, there is clearly more impactful bass attack. Should have done this years ago!

Now, I just purchased a much more powerful amp, Krell FPB400cx, which should arrive next week. I will be interested to see if the introduction of the Krell will provide an additional incremental increase in bass slam, weight, and control over my current McCormack amp.

Just wanted to point out that the very act of reattaching the wires alone could result in a better connection than prior, though the folding part probably can't hurt.
@ Mapman,

Yes, while I was at it, I re-tightened the high frequency cable connections. My high frequency cables are Morrow SP2 with the nude termination. My amp terminals have a hexagonal segment, so this time I used a wrench to tighten down the connections at the amp tighter than I previously had done by hand. I also tried to really tighten down the connections on the speaker as well. I do believe this significantly improved my highs and mids.
slam is amp power + speaker effecience and it must be on the recording. when its right, you feel it viscerally.

I have never liked the term 'slam'. I always equate it to SPL (a better term). It all relates to the size of speakers in a given room. One would not want under-sized speakers in a large, ex-large, listening space.

I concur that the power amp plays it part as well.
Happy Listening!