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how big is your woofer, how big is your box, what's your sensitivity

Tony L said:
FWIW (and entirely without science / maths) I can barely see or feel any movement at all in my two active 12" infinite baffle subs at my usual 70-75db listening level. I doubt they ever move more than a mm or so unless dealing with a Hollywood Godzilla movie or something like that. I'm currently playing Talk Talk's Spirit Of Eden and I can barely feel any cone movement at all. They do cross over very low though, about 50-60Hz.
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Just been playing The Police in Dub with 95dB peaks (iPhone estimate), the cones move about 5mm pk-pk at the most. Had to turn it down, it's a bit irritating at that level.
Thankfully the B/L compensation means that even if I use the full 20mm pk-pk travel there will be minimal distortion.
 
merlin said:
To give you an idea, corner mounted bass modules that say require 4w to produce 100db at 1m would require as much as 256 watts placed in the middle of the room along side your satellites.
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If S-Man wants to listen at 80 dB, why should he want to produce 100 dB at bass frequencies?
 
S-man has been singing the praises of these speakers for years now, and I'm still unclear about what's clever about them. The claims seem very ambitious, so it's not surprising scepticism is on show.

Paul
 
Actually Merlin's posts have sown the seeds of an idea in my brain cell...

I have been considering going fully active with e.g. a DCX2496 for some time. It would be very easy to try out the boundary loading idea using this. Although it's trivial providing enough current for the bass units, my motivation is to see if it sounds better, not to improve efficiency per se.
 
Markus S said:
If S-Man wants to listen at 80 dB, why should he want to produce 100 dB at bass frequencies?
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If the track is mixed and mastered with peaks of say 90db in the studio, would you not want to preserve the frequency balance the engineers worked to?

I think one of the more impressive bass systems I've heard in a domestic environment was bizarrely Tony Sallis' old Meadowlarks in Swindon. It had full weight without being bloated.

I measured the setup using a mic and a Tact RCS. The room gain basically resulted in a more or less perfect 6db per octave slope, with output steadily increasing from 100hz down to circa 25hz. That setup sold a lot of people on Tony's audio know how.

In other words Markus, IMHO a bit of bass boost at normal domestic listening levels often restores the original scale and body. What causes issues is +/-10db responses in the bottom two octaves which people often mistake for too much bass.

I'm truly amazed no one has introduced a dynamic dsp based loudness control in these days of PC audio and sharc processors.
 
Paul R said:
I'm still unclear about what's clever about them.
Paul
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Clever is a subjective term, so I can only tell you what I think is clever about the system:
1) The drive unit correction enables any size drive unit(s) to produce bass as low as you want in a much smaller box that is normal - all within the limitiation of volume displacement of course.
2) The 1st order rolloff inherently means that the transient response is very good, certainly better than a 2nd order system (acoustic suspension) or 4th order system (vented box).
3) The compensation scheme also reduces drive unit distortion by around a factor of 10.

But, the real question is what are the benefits:
1) Lack of overhang in the bass makes music sound better
2) It's all scaleable, any combination and size of drivers can be used depending on the bass extension and loudness potential wanted.
3) It's significantly smaller = more WAF, than conventional system for the same frequency range.
4) Lots of potential to apply equalisation (like Merlin's post above) and add a "Q" knob to increase the Q for personal preference and acoustics.
5) It would be easy to add a dynamic SPL dependent -3dB control

Anyway, you will all be relieved to read that this is my final post on the topic. Despite all the claims that you are all trying to help me, I'm feeling a lot of negativity, and as I said in post #93:

What's your sensitivity:
I am quite sensitive, so be nice to me.
:)
 
S-Man said:
ATC 100s don't go much below 35Hz and the B/L curve probably flattens off quite a bit at high excursions - so I'm not surprised.
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They begin to roll off at 35, measured anechoically, but with room gain they go very much lower. High excursions with the ATC 100s bass drivers is not something I experienced in 10 years of ownership. I think it would be bad for your hearing.
 
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This is what you've been going on about all this time? Not what I'd pictured in my mind's eye, I must confess. You reckon they have better bass performance than ATC 100s?
 
I bought two of the bastardest subwoofers in order to make ponies dance, I could post a lot of guff justifying it, but really, bass is all I care about and dancing plastic ponies is a consequence of my obsession with the two things that matter to me.

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I am considering two more, oh the fun one can have.
 
S-Mans designs were sounding very clean and controlled in a sea of boom at Scalford that year.
I'll take a good clean controlled LF able to work convincingly at normal listening levels (with some headroom of course) over quantity and extension any day.
To have both is nice of course but you need the right environment to enjoy it. Something most hi-fi enthusiast don't have and why the fixation on huge bass drivers capable of massive SPL and excursion is misplaced IMO.
 
Robert said:
S-Mans designs were sounding very clean and controlled in a sea of boom at Scalford that year.
I'll take a good clean controlled LF able to work convincingly at normal listening levels (with some headroom of course) over quantity and extension any day.
To have both is nice of course but you need the right environment to enjoy it. Something most hi-fi enthusiast don't have and why the fixation on huge bass drivers capable of massive SPL and excursion is misplaced IMO.
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Robert,

This thread is about proper bass reproduction. Sort of. The reasoning why bigger drivers are better in general for bass is upthread. Bass drivers should never bottom-out, but small ones will if pushed too hard, and they will also distort more at any given SPL than larger ones.

I'll stick with my boomy old 15" Super-Linears, even with the overhanging, slow, ports of shame - which obviously ruin everything.
 
James said:
Acceptance is the last step to recovery. Congratulations. See? It wasn't that difficult. :)
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Thanks. The bass in ATCs is absolutely spot-on, IMHO. Since the ports are just there to provide a spring-load for the bass drivers, and not to augment output, they don't interfere.
 
Blzebub said:
Since the ports are just there to provide a spring-load for the bass drivers, and not to augment output, they don't interfere.
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Ports offer the stiffest 'loading' for the woofers at resonance. If they are working as you suggest, then they must produce maximum 'output' at their tuned frequency. The easiest test is to put a lit candle or tissue in front of the port and play some music.
 
The ATC ports are not a typical reflex port implementation. They have a third-order roll off, i.e. between a typical reflex port and a sealed box.
 
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