I have previously done measurements at a distance of 2 meters, which were suited for higher resolution for the gated measurements. But as my listening room is fairly small, 4,27(L) x 5,08(W) x 2,6(H) meters, there is too much work required to make the space as reflective-free as possible, like moving the sofa and so on. Unfortunately, I’m not able to make any outdoor measurements.
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ATC speakers / Monitors
- Thread starter Pearljam5000
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I have previously done measurements at a distance of 2 meters, which were suited for higher resolution for the gated measurements. But as my listening room is fairly small, 4,27(L) x 5,08(W) x 2,6(H) meters, there is too much work required to make the space as reflective-free as possible, like moving the sofa and so on. Unfortunately, I’m not able to make any outdoor measurements.
This. If we want to avoid different path lengths from the tweeter and the midrange at different distances, the measuring axis should be halfway between the tweeter and the midrange driver.
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Not for a loudspeaker that has the acoustic axis at the height of the midrange driver, which is the case for all the ATCs three-way speakers.
Yes I know that ATC's claim about the main-axis, but geometry is geometry, you can't change that with words.
So, if the main-axis is not between the tweeter and the midrange then measuring/listening at different distances results in different path lengths, hence the phase relationship (and summed frequency response) will change between the drivers, depending on the listening/measuring distance.
I suspect the 3-way ATC-s have a downward firing main lobe, because they use symmetrical crossovers but the acoustic center of the midrange driver is further back compared to the tweeter, hence the main lobe is firing slightly downward. They don't use timing compensation in their crossovers, nor proper waveguide for their tweeters, both can be solve that "problem".
Saying that the midrange axis is the main axis is a compromise from them.
If you ever built a proper loudspeaker, you know what I'm saying.
Ultrasonic
Addicted to Fun and Learning
When I checked how the response varied with listening position height it was best at the height of the mid-range driver, so I do think there may be something inherent to the design that favours this, even on the passive model.
I think they do on their active models:
Active Amplification - ATC Loudspeakers
Active Vs Passive – What are the benefits of an active loudspeaker system? 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...
atc.audio
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DSJR
Master Contributor
They'll only go in studios I suspect, although a couple of anal domestic enthusiasts might give 'em room to play
Something to kind-of compete with PMCs giant studio monitors (these subs plus traditional 300As, but do many studios still use this kind of soffit giant these days?
I freely admit, that for domestic or prosumer use, there are better cheaper options now. ATC do have a head start in the general domestic market as their products are available in dealer chains here, where makers such as PMC (I think), Focal, Dynaudio and others, do seem to separate the ranges out and not sure if the two sides meet in larger dealers.
Try to measure at different distances but strictly at the midrange driver's axis, it is possible that you will see change in the frequency response as you change the distance.
It doesn't matter if it is a compromise, the acoustic center is still at the height of mid-dome driver in practice. And you are right, the main reason is that the tweeter driver is more shallow than the mid-dome driver, but that is easily adjusted by tilting the loudspeaker a few degrees by adjusting the length of the spikes.
In a studio environment with the SCM25s, the user should raise the speakers so that the mid-dome driver is a little above the ear height, as the acoustic center is actually a few degrees under the mid-dome driver.
There are many misinformation in that "article". Like that passive crossovers can't change the timing.I think they do on their active models:
Active Amplification - ATC Loudspeakers
Active Vs Passive – What are the benefits of an active loudspeaker system? 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...
Yes, but this way if you change the listening distance, you need to change speaker tilting or listening height as well to get the same response.
Ultrasonic
Addicted to Fun and Learning
It's obvious I will definitely see a change, which is why I measured at the listening range in the first place. And why I looked at the height effect at this range too, to enable an informed decision about whether to tilt the speakers back to align with the mid-range driver or not.
Thinking back to your comments about 2-way designs, my understanding was that most were intended to be listened to with the tweeter at ear height btw, so I think there's more to this than just focusing on if the response varies with distance.
If the main axis/lobe is not in between the typical tweeter and mid(woofer), then the response will change as you measuring/listeing at different distances on the same axis. That's all. I don't know the main reason why manufacturers do the main axis to the tweeter (or other driver) axis.
Ultrasonic
Addicted to Fun and Learning
I needed a 4° tilt I think, and so actually ended up removing the rear spikes entirely and getting some slightly longer ones for the front.
Ultrasonic
Addicted to Fun and Learning
The article I linked to doesn't say that passive crossovers can't or don't change phase. What it says is they don't independently adjust amplitude and phase. Which I think is correct? The reason I linked to it though was to make the point it at least implies that they do make some phase corrections on their active models, although I can't be certain that they do.
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Pearljam5000
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The new ATCs
OP
Pearljam5000
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It's not correct because passive filters/crossovers can also do this. DSP is a litte different story but ATC don't use DSP.
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Presumably passive crossovers and active analogue (not DSP) crossovers have exactly the same limitations, it just gets bigger and more expensive quickly with the passive high power ones.
Real world experience tells me it's just not at all a problem ¯\_(ツ)_/¯
ATC still playing the "waveguides are lava" game with two ways.