View Full Version : What gives a speaker SLAM?
DarrenHW
16-05-2015, 08:42
Apologies if this is a stupid question, but how come some speakers have slam and some don't?
Where does it come from? I thought it would all be in the bass driver but I've read some threads that say the mid is also part of the equation as most of the "action" occurs above 70Hz?
How does the cabinet come into the equation, are some designs better than others?
Is there a trade off between how low a speaker can go and how hard it can it hit?
I suppose it depends on how you are defining 'slam' but if you mean the sound having physical presence in the room then I'd say it is down to the amount of air being moved at bass/mid bass frequencies. So I'd say it would be a function of the amount of bass driver area and the lowest frequency able to be reproduced audibly.
eddieedwards
16-05-2015, 09:22
I agree with Martin, but it could also have a lot to do with the amp's ability to control the speaker. This can help provide "slam" and pace, rather than a slow plodding bass.
How long is a piece of string?
DarrenHW
16-05-2015, 09:59
I suppose it depends on how you are defining 'slam' but if you mean the sound having physical presence in the room then I'd say it is down to the amount of air being moved at bass/mid bass frequencies. So I'd say it would be a function of the amount of bass driver area and the lowest frequency able to be reproduced audibly.
A good question, I should have clarified what I mean by slam, as you've been to Marco's I can explain this easily to you. It's what he assaults you with, with his Tannoys! (I have no delusions of achieving that level of "slam" at this point in time btw.) So by slam I mean hit in chest with bass.
(Apologies if I'm misinterpreting what you're saying but...) I've heard KEF 105.2 powered by mono blocked Quad 405's similar (but reworked to a higher standard than I'm currently at) to mine, I loved their presentation but was a little underwhelmed by the slam in comparison to the 44's (admittedly listening at lower volume than I'm used to). Both have 12" bass drivers and sealed cabinets, the 44's have an internal volume of ~50 litres the KEF's 70 litres, so could the smaller cabinet of the 44's offer the answer i.e. would housing the KEF driver in a smaller cabinet increase slam, or is there more too it than that?
Damping factor of the amp can play a part too, the ability to control a loudspeaker cones movement.
It's all about moving a lot of air, then stopping it quickly.
For me, slam is very much what Gazjam says. It sounds instant - massively quick.
The high surface area and very low mass of large Apogee bass drivers deliver very good slam. Far more so than large ESL panels but I think that is a function of force per unit area. There is just more force available from planar magnetic membranes than mylar film/ESL ones.
Large cones like the Celestion 66 can deliver great slam too, proving that the mass of the driver, inevitably higher than planar membranes, can overcome this with large magnetic force. However, the larger mass probably leads to cone overshoot at high volume which probably adds more slam.
High excursion, LF long throw drivers add punch, I think, which is different. It travels through room boundaries and car bodies far more readily than low excursion high surface area drivers do. TBH my Martin Logan Descent woofer used to drive my wife crazy for this exact reason. I sold it:D
EDIT: aberrations in frequency response can also add/detract to the amount of perceived punch/slam. Try messing with JRivers's PEQ to add +5DB at 60Hz, for instance. You may feel you have more slam as a result.
A good question, I should have clarified what I mean by slam, as you've been to Marco's I can explain this easily to you. It's what he assaults you with, with his Tannoys! (I have no delusions of achieving that level of "slam" at this point in time btw.) So by slam I mean hit in chest with bass.
(Apologies if I'm misinterpreting what you're saying but...) I've heard KEF 105.2 powered by mono blocked Quad 405's similar (but reworked to a higher standard than I'm currently at) to mine, I loved their presentation but was a little underwhelmed by the slam in comparison to the 44's (admittedly listening at lower volume than I'm used to). Both have 12" bass drivers and sealed cabinets, the 44's have an internal volume of ~50 litres the KEF's 70 litres, so could the smaller cabinet of the 44's offer the answer i.e. would housing the KEF driver in a smaller cabinet increase slam, or is there more too it than that?
if you reduce cabinet size for the same bass driver you increase the Q of the system so you will lose some bass depth but increase bass volume compared to the other frequencies. That is my facile understanding, anyway. With Tannoy Lockwood you have a big, lightweight driver with a big magnet in a very big box so that gives, to an extent, the best of both worlds - bass extension and as Gaz says the ability to move a lot of air and stop it fast. So you get a punchy lower mid-bass which is the 'hitting you in the chest' bit, but also bass weight at lower frequencies too. Wheras the Akais I use have the same size bass driver, also light and with a big magnet, but in a much smaller cab so you get the mid bass punch but not so much the deeper bass.
Cabinet design and box coloration, internal bracing even crossover design can all impact slam in a speaker too.
My Eddindales take an interesting approach...
Rather than use a single big bass driver, They use 4 smaller 6" woofers wired in series/parallel, which spreads the bass duties between them.
A lot more agile than a single big woofer, even when moving a massive ammounts of air the drivers hardly move.
This wouldn't be the case if it was one large driver. A lot less distortion as well so each driver works more efficiently.
Again though it's a synergy thing.
In a speaker the crossover has to be good enough to talk to the drivers, which have to be properly configured and voiced, but can only be as good as the cabinet is constructed.
So it's only as strong as its weakest part, and box speakers that do big bass can sometimes sound a bit loose and lose "slam" if all aspects of the design aren't equal.
and box speakers that do big bass can sometimes sound a bit loose and lose "slam" if all aspects of the design aren't equal.
Yes, or the bass can be deep and plentiful but soft i.e with little impact or slam. There can be all sorts of reason for it. Speaker position and the size/shape/construction of the room as well. That's the trouble with this hi-fi game isn't it? Everything matters to some extent.
That's the trouble with this hi-fi game isn't it? Everything matters to some extent.
Yup - it is like the laws of physics are a complete bugger. Somebody seriously needs to find a way around these laws.;)
Sick of them, personally...
Best I've heard/felt was listening to an all Linn system and thought I was having a heart attack:eek:
I couldn't actually hear the bass, but by God I felt it, right in the chest, really weird to be honest.
Audio Advent
16-05-2015, 18:49
How about how phase effects things? If the phase of the sound is changing between the drivers (some mids for example will be wired up the opposite to the other dirvers) then somewhere in the transition between them as they cross over will be some frequencies getting out of phase from the two drivers. I can't help but think that any cancellations of any kind due to phase effects will cut out a whole load of fast moving, transient sound waves - the sound will be softened.
Efficiency of the drivers often helps. Aren't tannoy drivers relatively efficient?
Audio Advent
16-05-2015, 18:50
Best I've heard/felt was listening to an all Linn system and thought I was having a heart attack:eek:
I couldn't actually hear the bass, but by God I felt it, right in the chest, really weird to be honest.
Wonder how many people have had heart attacks and thought they were listening to Linn (such was the pain?)
The Black Adder
16-05-2015, 18:53
Yup... BIG Tannoy's are bloody great for a good slam. :)
Wonder how many people have had heart attacks and thought they were listening to Linn (such was the pain?)
:lol:
Thetiminator
17-05-2015, 08:25
High powered amps with easy to drive speakers is a good recipe. I ran Triangles with 800w of Electrocompaniet mono's and the effects were frightening......
Firebottle
17-05-2015, 11:09
with 800w of Electrocompaniet mono's and the effects were frightening......
:eek: :mad:
spendorman
17-05-2015, 12:35
Absence of crossover components perhaps.
jandl100
17-05-2015, 14:52
What gives a speaker SLAM? ....
Can't achieve it without appropriate amplification. You need an amp that has that level of control and grip.
If my current experience is anything to go by it's two Crown XLS1500s running in bridge mode & ZZ Top :eek:
Audio Advent
17-05-2015, 15:21
Absence of crossover components perhaps.
I think active helps - not least of all because in a commercial system at least the power should be matched to the driver's requirements.
I wonder how much the back pressure on a driver due to cabinet design effects the damping of the bass driver's travel and therefore slows things down too.
https://www.youtube.com/watch?v=OZsjQBtEZ6M
Play loud at 4 minutes 30 if your system has slam you will surely know about it:)
This album (A Flock Of Bleeps from 2003) is a masterpiece of electronic wizardry.
"slam" as has been said in some posts above is pretty simple to define in terms of how a design delivers it:
A speaker needs to move a lot of air, have good bass control (speaker/amp match must have sufficient damping factor and pistonic speakers benefit from having relatively stiff and lightweight cones) and be capable of high SPL in the bass region.
Small speakers can have a fair degree of "slam" too (the Raptors do) as long as they use long throw drivers to move the air and have adequate wattage up 'em. Problem with most smaller speakers is that distortion can generally increase with excursion. This applies to many but not all (revelators for example, have some of the lowest distortion figures going at maximum excursion compared with most drivers of similar size). Generally, big (and stiff) driver, in a big box, with low excursion and distortion = decent (some would say "accurate") bass. Some big electrostatics and panel speakers have it too but may be compromised in other areas. All loudspeakers are a compromise.
alcarmichael
08-10-2015, 17:53
https://www.youtube.com/watch?v=OZsjQBtEZ6M
Play loud at 4 minutes 30 if your system has slam you will surely know about it:)
This album (A Flock Of Bleeps from 2003) is a masterpiece of electronic wizardry.
Wizardry indeed. Sounded like I was listening in 5.1 surround sound!!!
Haselsh1
08-10-2015, 18:03
The best I have heard a 'Flock of Bleeps' sound in my system was with a Samson Servo 600 amplifier which provided effortless bass with a massive amount of slam. Not exactly Hi-Fi though.
walpurgis
08-10-2015, 18:09
This album (A Flock Of Bleeps from 2003) is a masterpiece of electronic wizardry.
Been playing that for years (not all the time obviously :)). Great album and recording, you should hear it through my Tannoys! Might be an acquired taste for some.
Another with real slam is 'Movements of Consciousness' by Prahlad.
http://i57.tinypic.com/2chtfy8.jpg
You might like that Justin.
spendorman
08-10-2015, 18:24
https://www.youtube.com/watch?v=OZsjQBtEZ6M
Play loud at 4 minutes 30 if your system has slam you will surely know about it:)
This album (A Flock Of Bleeps from 2003) is a masterpiece of electronic wizardry.
Can someone retrieve the bass cones of my LS3/6's please!
an 8 year old kid with a tennis racquet:doh:
spendorman
08-10-2015, 20:14
an 8 year old kid with a tennis racquet:doh:
Yes, they did make a racquet as they left the chassis.
As a lover of the more 'aggressive' styles of music, 'slam' is absolutely critical to me in reproducing music with passion.
-
In addition to what's already been stated regard to grip and control of the speakers which I agree is absolutely critical, to me it also involves the following:-
1) Solid State Amplification (with heavy iron transformers) in abundance (My 3 Klouts provide a total of 960 'clean' watts)
2) Speakers with good (read accurate) frequency response
3) Speaker drivers with old fashioned ferrite magnets
My reasons for stating S/S amps with transformers and speakers with ferrite magnets are simply that in my experience, the more modern alternatives not only lack slam but also sound weak and un-musical!
I will also say that although valve equipment is certainly capable of delivering slam, in my experience it is a smoother and 'rounder' experience and altogether not aggressive enough for me. (That said I do swear by valve based guitar amps. With very heavy transformers)
The same is true of musical insturments; using class D power amps to drive 'lightweight (neodymium magnets)' speakers is a very clear and what I call 'modern' sound but quite simply lacks involvement and balls!!
Slam is down to the transient response of the speaker, and critical damping. There must be no overhang or you'll get boom rather than slam. Amps do also play a big part i.e. some amps are capable of producing the slam available in a speaker, and others can't control the speaker, so again, you end up with a 'looser' bass end.
High quality transient current response and a speaker capable of delivering the signal and drivers that are fast, high quality magnets, cone material, cone excursion, port configuration (if used) and source that can make the other equipment in the chain perform as designed (providing the design is correct)
Haselsh1
10-10-2015, 08:16
I've heard my current KEF Q500's perform with a massive amount of slam on Younger Brother's 'Flock of Bleeps' album using a Samson Servo 600 stereo amplifier and I have heard them perform with my current Rotel monoblocks and these have nowhere near as much slam as the Samson so, as far as I am concerned, most if not all of the slam is down to the power and control of the amplifier.
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