I also understand it that way. Apparently the latter is more difficult to implement though. If the multiple units aren’t matched or aren’t exactly in sync it gets muddy.
Do you mean to say that the bass should be fast too? My PMC T5.21i speakers do fast bass really well (as well as fast rhythms) Is it accurate? Mm. Still not sure. Tight may be a better word. There are some songs that sounded much differently before. Most sound better than before. One example where I was disappointed: Simply Red’s ‘Picture Book’ bass sounded warm and pulsating on previous (Dynaudio and Mission) speakers, but on the PMC’s it’s almost withdrawn. Most warmth is sucked out, up till the sparsely arranged bridge, where the Uniti puts it more center stage (for lack of other instruments maybe). Could be the recording quality (after all this was the Eighties) but how can one have proof if the recording is bad or not? I don’t have the sound enigineer’s phone number to ask.
The PMC’s high frequencies are tilted up too, you may not like that either.
Perhaps one reason why active speakers are perceived (correctly in my admittedly biased view) to be fast.
Roger
I think a speakers ability to sound fast is related to the amps ability to drive it.
If you have a low wattage valve amp you need a high sensitivity speaker 100+ dB so it can control the drivers properly.
If you have a low sensitivity speaker like 83/84db then you might need 100+ watts to make that speaker sound fast.
I find PMC’s are pretty fast and agile…
2 Likes
The passive version of my ATC SCM40s has quoted sensitivity of 85db but the active version has over 240w of power amp and no passive crossover to go through. I suspect this is a big factor in their speed. They certainly sounded a lot faster than passives driven by a 250DR when I did a comparative audition.
Roger
2 Likes
Yeah for sure!
Power definitely not the limiting factor there.
ATC’s have huge magnet motor systems so need a fair bit of power I imagine.
I am sure that if they were to be driven from my 40 watt Atom they would sound quite ordinary and possibly labelled slow.
I guess that’s also comparing an 80 vs a 240 watt amp. I’d say too many variables to simply point at one like active vs passive.
That’s not what he’s saying. He is saying the increased power is what increases handling and therefore speed or perception of speed.
I too thought that fast and clean low end could only be achieved with small drivers. Until I heard Magico speakers…
Smaller drivers have to have a larger excursion to produce the same frequency as a large driver moving a tiny amount. Big drivers move more air and if sensitive enough, or powered adequately, will have a big impact. Think about rock concerts. That attack comes from many huge drivers.
1 Like
That is providing adequate power for peaks, but as described in an earlier post power is not everything - power delivery across the impedance range of the speaker, and a low enough output impedance can also be significant for adequate control of the driver cone(s)
The power amp’s speed of power delivery of course also plays a part.
A bit of a generalisation, perhaps true at the time when valves became a thing and people tried resurrecting old models.
I am happily driving LS5/9s with 13 watts. Thing is they are Tim de Paravicini watts, one thing that is often written about his designs, the bass is not typical of valve reputation. He explained it was down to transformer design.
My listening amongst others, for speed is the bass line on Black Uhuru, Botanical Roots, for slam, which to me is also speed related, Rhiannon Giddens, Waterboy.
1 Like
Yes, but only if you replace one driver by a smaller one. What @anon4216120 was talking about is replacing a bigger driver by multiple smaller ones.
It’s essentially about the amount of air that’s moved
- one bigger one with little excursion
- a smaller one with a lot of excursion
- multiple smaller ones (with the combined surface area of the bigger one) with a little excursion
All amounts to the same.
Just ask @Mitch whether his speakers do bass. Not a big driver in sight.
1 Like
The difference is that the mass of a large cone has more inertia, so is slower to accelerate and decelerate all else being equal. But of course all else is not normally equal, with different magnetic motors, so less easy to predict differences in acceleration and deceleration ability, and linearity of power response, while as someone pointed out earlier with the multiple small driver approach there is the added variable of matching mechanically and electrically so all move perfectly in unison.
That is why there are ‘fast’ speakers with bigger bass drivers and slower ones with smaller, as well as vice versa.
1 Like
Something like dynaudio exite x14 or audiovector qr 1 will fit that discription I guess.
Nailed it!
1 Like
Yeah of course, i get that. So why is it that as we see the majority of super high end loudspeakers like the big wilson’s, big b&w, big focals etc, using large woofers? Why don’t they all use multiple smaller drivers? I would assume there are advantages and disadvantages to both. To make the same surface area as a 12" takes nearly 4 x 6" drivers. i suppose it is a balance between performance and aesthetics and what the designer wants to achieve. i personally like the looks of bigger drivers in speakers vs lots of smaller ones.
I suspect cost is a big factor. 2 x 8" drivers don’t even make that of a 12 " and i suspect that 2 x 8" drivers of a similar quality would cost more than the 12" alone.
Just found this
4.00" = 12.57 sq.in. = 1.00
5.00" = 19.64 sq.in. = 1.56
5.25" = 21.65 sq.in. = 1.72
6.00" = 28.27 sq.in. = 2.49
6.50" = 33.18 sq.in. = 2.64
7.00" = 38.49 sq.in. = 3.06
8.00" = 50.27 sq.in. = 3.999 = 4.0
10.0" = 78.54 sq.in. = 6.25
12.0" = 113.1 sq.in. = 8.997 = 9.0
15.0" = 176.7 sq.in. = 14.06
My Grandinote Mach 36’s have 36 drivers and 25 tweeters. They reproduce incredible bass. come over and listen to “Fanfare for the Common Man” by Copeland and I think you’ll agree!
8 Likes
No doubt! 
I wish i could take you up on that offer!