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Thinking about a pair of ATC SCM40

DavetheBass

pfm Member
I recently heard a pair of these at a demo and was mightily impressed. I'm aware they take a bit of juice to get them going. That shouldn't be a problem as I have an H390. I was wondering about placement. Our lounge is 11 ft across and 21 ft long. The speakers will be firing across the shorter distance, so can't be too far in to the room. I'd be grateful for your thought or experiences.
 
Pretty much the same width as my room,with SCM40s in,sound perfectly fine in my room(solid floor) and measured with rew and looks fairly acceptable,I’m using a nad C298,considering getting another and bridging them so I’ve got 600 watts per side,sufficient I’d imagine
 
This is a similar thread to one i started after hearing the SCM40's, and being impressed with them. One other recommendation, after receiving replies to the original thread, would be to audition against the 40A's (Active model) as many say this is appreciably better than the passive model. Sadly both models are too large for my room, but one day...
 
You listen on a good set of headphones.

True you don't get a good idea of how they sound IRL.

But there is an apparent difference though surely much less clear than if sat in front of the speakers (obvious).

Actives sound quite a bit more open and clear.
 
Even the Hegel is a mighty amp, I'd definitely consider actives supported and financed partly by selling that amp, getting a proper and useful preamp only should be possible, but listen yourself should decide.
 
You listen on a good set of headphones.

True you don't get a good idea of how they sound IRL.

But there is an apparent difference though surely much less clear than if sat in front of the speakers (obvious).

Actives sound quite a bit more open and clear.

I’m thinking that the slightly different speaker location, plus the recording microphones and their location, plus your playback system would likely far outweigh (and/or mask) any actual differences in those two setups.

Which headphones do you use OOI?
 
According to ATC: (obviously they don't know as much as randoms on YouTube, or hifi forums, but they have made active and passive versions of the same speakers for decades)

"Passive speakers use crossover filters that only employ passive components (capacitors, resistors, inductors) and the crossover filters are ‘located’ between the power amplifier and the loudspeaker drive units.

Active loudspeakers use active (powered) crossover filters and the crossovers are ‘located’ before the power amplifiers. Each loudspeaker drive unit (two in a 2-way, three in a 3-way) has it own dedicated power amplifier, fed from the output of the active crossover.

While it is possible to design a high performance loudspeaker using passive components, an active design has a number of benefits, these are listed below;

1) More accurate crossovers
  • Active filters allow independent control of level and phase(time). This is not possible with passive crossovers. With a passive crossover any changes you make to the circuit affect both level and phase. The benefit this allows is that we can adjust for the crossover to have a perfect magnitude response and phase response. The result is that the stereo imaging is much more stable and the tonal balance of instruments is improved.
  • An active filters performance is not changed by the temperature of the drive unit voice coil as they are not directly connected to them. A passive crossovers performance (filter shape and crossover frequency) will change with voice coil temperature which, increases with SPL (input power). This leads to passive loudspeaker systems having a slightly different sound when driven at low SPL compared to high SPL. The performance of active ATC systems changes very little with drive level.
  • More efficient crossovers. Active crossovers do not need to use series inductors to achieve their filter shapes. Series inductors have resistance that reduces bass driver efficiency and also increases the Q of the low frequency tuning.
  • More cost effective crossovers. Passive crossover networks use large, bulky and expensive components in order to deal with the high voltages from a power amplifier. Active crossovers offer better performance for lower cost.
2) Lower Intermodulation-Distortion

As the separate amplifiers in an active system are located after the crossover, they only operate over a limited bandwidth. This reduces intermodulation-distortion and, in comparison to a passive system, even a bi or tri-amped passive system, an active system will show 15 – 20dB lower intermodulation distortion.

3) Improved Frequency Response and Stereo Matching

An active system can very simply feature individual gain trims for the two, three or four amplifiers involved. This allows very simple fine tuning of the frequency response and the stereo matching. Similar matching in a passive system would involve the replacement of large, soldered passive components which, in practice, is difficult and time consuming for the manufacturer.

4) Lower Cost for Higher Performance

Because an active system is designed, engineered and implemented by a single manufacturer into as compact a package as the design allows, cost is saved on electronics case work and packaging and the manufacturer can invest in real performance enhancing changes or pass the saving on to the customer."

To which I would add:
- a much neater and more domestically acceptable system, since you don't need a big amp, you'll likely not need a huge hifi rack/scaffold, balanced cables are much less intrusive and less expensive than the stuff you use for passive speakers
 
I suspect that anyone hearing the passive 40s and active 40As, regardless of the quality of the amp(s) driving the former, will buy the actives. And the Hegel is a mighty fine amp.

The venerable @Musicraft will be along in a moment.
 
How the heck can listening to a recording of two (slightly differently set up) sets of speakers, played back on your own system, with its own limitations, give the slightest clue as to how the speakers in question actually sound?


And with the actives being a few db (1.2db) louder the last time I watched it and measured it with a calibrated app
 
Many thanks for the replies guys. Luckily, the retailer that I'm using has an active set. So I can do an A/B test. Albeit with a different front end. He is a chord dealer, so maybe a Hugo tt2 in front. Now I'm looking forward to Thursday even more ;)
 


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