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Active or passive, does it matter?

Ah so the magazine measured (and presumably listened) with the bass boost switched to on ?

A bit of a faux pas for Stereoplay ?
 
No Merlin, in fact I was suggesting that this was not the issue, since the bass trim centres in the region of 40Hz, and you are drawing attention to the 20-30Hz area as I understand it.

There is a little bump around 35Hz, but since this appears also in the passive measurements albeit to a lesser extent, we can hardly lay this at the feet of active EQ.
 
Darren,

Take a look at the measurements - the change in alignment takes place at 40hz. Look at the octave below that in both FR and distortion. Look at the contour in particular.

It's clear to me that there is an electronic boost. Paul's mention of the bass alignment facility explains that.
 
The graphs differ quite a bit across the whole spectrum, if one has the inclination to look beyond deep bass, so much so I'm not even sure how they aligned the graphs (not at 1kHz anyway and not, it seems, consistently between the two kinds of measurement). These graphs are just not enough evidence for me but I will try to keep an open mind till I hear back from ATC.
 
Tony L said:
Can they be switched between free-space, half-space etc?
Click to expand...
I guess that's the effect. But I would expect the room treatment to have more impact on whether the bass needs lifting. I've never felt the need to twiddle.

Paul
 
Blzebub said:
Neither of my two pairs of active ATCs have had this.

Anyway, satisfying to see persistent antibodies.
Click to expand...
I think both pairs will have (had) the facility. Maybe not revealed to the outside in your early domestic model.

The 'discrete' amp packs look very much like they share the topology of the 'integrated' ones, and they have a lot of adjustment possibility. Best leave them firmly inside the speaker cabinet...

Paul
 
I would expect the actives to offer a flatter response across the mids given the phase coherence of the active crossovers employed. That doesn't surprise me.

The alignment in the bass is the stand out difference for me. Not that this is a criticism I should add - although I would agree with ATC in that the bass boost is best left out of circuit.

If you want deeper bass, simply buy bigger ATC's. Same result without the distortion.
 
I'd have expected it to be a bass cut, not a boost, i.e. a switch for wall / soffit mounting rather than near/mid-field. I can't see why one would want to lift the bass beyond a free-space 'flat'. Most studio actives have a switch on the rear usually corresponding to free/half/quarter space.
 
In studios it can sometimes help to boost the bass a very small amount particularly for smaller near fields to prevent the engineer/producer from mixing with too much bass energy, note that minimum no of clicks on this (indented pot for ATC 20A Pro) would be advisable.

For playback flat ought to be best unless the room/source/control gear has (where's the bass gone) issues and of course to suit taste (which rightly overrules all other's opinions)
 
The reason for providing a bass lift with some accurate speakers is because the most pleasing FR curve at listening position has a bass lift (often called a house curve) and a treble droop.
I found my SCM50a's extremely and surprisingly bass light in a good room , mine had no provision for lifting bass at all (didnt see the holes)

Here is the "ideal" curve

bandk.jpg
 
Rodney gold said:
The reason for providing a bass lift with some accurate speakers is because the most pleasing FR curve at listening position has a bass lift (often called a house curve) and a treble droop.
I found my SCM50a's extremely and surprisingly bass light in a good room , mine had no provision for lifting bass at all (didnt see the holes)

Here is the "ideal" curve
Click to expand...

Rodney - why is that "ideal"? Who says? (Not being picky; genuinely interested). Is the bass lift shown what happens to a "flat" speaker in a decent room, or is it intended that the speaker/system itself should have such a lift?
 
That is the most pleasing target curve at listening position
The "ideal" speaker/room would have that curve at listening position if all the components "measured" flat.
Speakers are measured anechoically , not at listening position , you actually want the speaker to measure flat anechoically to generate that droopy target curve at listening position. (which it should do , due to room gain and treble absorption)
 
Rodney, have you considered that perhaps the positioning had you sitting at, or close to, a bass null? I can find spots in my room that render my ATCs almost bass-less at certain frequencies, but then I can also find spots that show great emphasis at those same frequencies, with the best sound being somewhere between the two.

I will agree, for the size of the speakers (ATC100 towers in my case) they don't wallop you with bass as you'd expect, but when it's there in abundance the speakers deliver. I think this is characteristic of a superbly controlled bass response, rather than anything deficient.
 
Here's a good example I found of the effect that room gain should have on the LF response of a loudspeaker, in this case with the speaker placed within the typical constraints of a living room.

EP2-BoundaryGraphicSS.jpg


I'm surprised that a studio would kill the bottom enough to make electronic reinforcement necessary as it makes so much more sense to cut bass levels electronically than to try to boost them - as Tony mentioned, I too find the boosting approach surprising. I would have expected the speaker to be designed to work in free space with a bass cut facility in place for sofit mounting.
 
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