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Floorstanding speakers - thin versus fat

The Accuton C173-6-090 is a contender for the ideal wide-bandwidth, high sensitivity midrange - at a staggeringly expensive price of USD1K each!

It's a bit on the big side, being a 6.5" driver, when I think a 5" version would be better and provide higher reach for the more critical MF/HF cross.
 
I auditioned the fact 12s for about 3 hours on the end of some very expensive electronics. They produced a nice, detailed, fast sound but I too found it lean sounding.
It wasn't bright because it was never difficult to listen to, which is what I associate with the term bright sound.
It did however lack bass impact, and the demo room was smaller than my own room so it was a definite no go for me.
I enjoyed listening to them because it was such a different presentation to my own speakers but I couldn't live with them, and definitely not for £12k
 
Warszawa said:
There's a good review with more thorough measurements here: https://pmc-speakers.com/sites/default/files/attachments/HiFi Critic fact.12 Review_0.pdf

I will admit PMC speakers can be over-priced, but now that the Signature model is out the original version are a great deal.
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Thanks for that - as expected, not everyone thinks the same about them! Agreed, it's now possible to get them (in perhaps not quite mint condition) at around £5-6k, which is certainly more affordable than original retail.
 
S-Man said:
SCM50s have rather fat and slow bass, which is a shame because the rest of the frequency range is excellent.
I have never heard the 40s, but they may actually have better bass due to their sealed box alignment.
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Odd, because I've seen a few (non professional) reviews describing the SCM50s as bass-light! I guess it depends what you're comparing them with. One of the things I like about the (passive) SCM40s is their controlled and non-intrusive bass.
 
indus said:
I auditioned the fact 12s for about 3 hours on the end of some very expensive electronics. They produced a nice, detailed, fast sound but I too found it lean sounding.
It wasn't bright because it was never difficult to listen to, which is what I associate with the term bright sound.
It did however lack bass impact, and the demo room was smaller than my own room so it was a definite no go for me.
I enjoyed listening to them because it was such a different presentation to my own speakers but I couldn't live with them, and definitely not for £12k
Click to expand...

That does seem to be a common theme - the lack of "impact" in the bass with thinner speakers. It probably does come back to the point made much earlier - in simplistic terms, the smaller LF units simply can't convey as much energy, due to their smaller area. It seems that a longer throw cannot compensate.

And I have to agree - the £12k price tag does seem a little high for what you're getting...
 
Antifon said:
That does seem to be a common theme - the lack of "impact" in the bass with thinner speakers. It probably does come back to the point made much earlier - in simplistic terms, the smaller LF units simply can't convey as much energy, due to their smaller area. It seems that a longer throw cannot compensate.
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SPL closely follows volume displacement and so a longer throw is theoretically fine. However, multiple small drive units will tend to have smaller displacements than a single large driver and the larger relative displacement of the small drivers will tend to create more distortion compared to the smaller relative displacement of the large driver. So a single driver is likely to be louder and lower distortion compared to several small drivers with the same area. This isn't likely to be a large factor when comparing a single driver with only 2 or 3 smaller drivers of the same area where adding an extra driver is likely to tip the balance in favour of the smaller drivers (towers often have space on the baffle to do this).

The problem with using something as tiny as 2 x 5" drivers (the size of midranges not a woofers) is that the area is well below what is required to reproduce low frequency transient sounds like, say, a kick drum at standard levels in typical rooms that are not booming. On the other hand, if the room is booming then a speaker that roll off the low frequencies and so reduces the level of room boom may well be preferable. Not high quality but preferable to speakers that maintain their output at lower frequencies. The use of subs can also make a major difference to sound quality and reduce the magnitude of the issues associated with insufficient cone area of the mains. Context matters.
 
Probably not what you want to hear but the signature model has more impactful bass.

The transmission line works well but if you like bass you can feel in your chest, there's no substitute for a big woofer.
 
Antifon said:
Odd, because I've seen a few (non professional) reviews describing the SCM50s as bass-light! I guess it depends what you're comparing them with. One of the things I like about the (passive) SCM40s is their controlled and non-intrusive bass.
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Quality of bass reproduction below a few hundred hertz is entirely dominated by the room, measurements will show you the actual in room response, bass extension, degree of roll-off etc etc.
Subjective terms such as ‘fat and slow’ have no meaning whatsoever.
Keith
 
indus said:
I auditioned the fact 12s for about 3 hours on the end of some very expensive electronics. They produced a nice, detailed, fast sound but I too found it lean sounding.
It wasn't bright because it was never difficult to listen to, which is what I associate with the term bright sound.
It did however lack bass impact …
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I understand that how people experience bass seems to be very personal. I admit I haven't heard the Fact 12 but I have heard the Fact Fenestria and the twenty5.X series for X=24 and X=26. To my ears they share a bass style that sounds very clean and low distortion despite their modest sized drivers [1]. I can see how that might be appreciated as lean and low impact (a valid matter of personal taste, of course). I though the bass style was rather impressive given the modest driver size.

I saw @S-Man's opinion on the SCM50. I do have a different view. I auditioned the SCM40A (sealed) and SCM50A (ported) back-to back in a morning session at my dealer. Explicitly to judge the difference between their bass loadings, since I wanted to get away from the bass overhang of my then loudspeakers. On my test material there were some differences but not significant enough to worry me. The SCM50 port seems to be tuned to a rather low 22 Hz [2] so AIUI [3] from 40 Hz or so upwards (most of my listening) the box will substantively behave as if sealed. I don't personally perceive the SCM50 bass on mainly classical material (some jazz) the same way as @S-Man - but it may depend on individual musical taste and experience.

[1] Corresponding AIUI to how the PMC transmission line's performance is described in Newell and Holland's book "Loudspeakers …" (section 3.4 on Acoustic labyrinths).

[2] From the impedance amplitude curve in the SCM50 HiFi Critic review here. Marks available if you can explain the top end of the phase curve.

[3] Very much as a loudspeaker amateur - but one interested enough to have read some books on loudspeakers. "A little learning is a dangerous thing" of course.
 
John Phillips said:
I saw @S-Man's opinion on the SCM50. I do have a different view. I auditioned the SCM40A (sealed) and SCM50A (ported) back-to back in a morning session at my dealer. Explicitly to judge the difference between their bass loadings, since I wanted to get away from the bass overhang of my then loudspeakers. On my test material there were some differences but not significant enough to worry me. The SCM50 port seems to be tuned to a rather low 22 Hz [2] so AIUI [3] from 40 Hz or so upwards (most of my listening) the box will substantively behave as if sealed. I don't personally perceive the SCM50 bass on mainly classical material (some jazz) the same way as @S-Man - but it may depend on individual musical taste and experience.
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Thanks - that's another concern I had: how well does ATC make the transition from the largest sealed box design (SCM40) to the lowliest of the ported designs (SCM50) while still retaining their characteristic "house sound" (to use a term that many would probably dislike). Apologies if you've already said earlier and I missed it, but what did you end up buying?
 
Antifon said:
Odd, because I've seen a few (non professional) reviews describing the SCM50s as bass-light! I guess it depends what you're comparing them with. One of the things I like about the (passive) SCM40s is their controlled and non-intrusive bass.
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SCM50 are not bass light. The bass is a bit thick and ploddy sounding.

IMHO.
 
Purité Audio said:
Quality of bass reproduction below a few hundred hertz is entirely dominated by the room, measurements will show you the actual in room response, bass extension, degree of roll-off etc etc.
Subjective terms such as ‘fat and slow’ have no meaning whatsoever.
Keith
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And once you have a relatively good sounding room, which is as easy as falling off a log if you like traditional homes with traditional interior design and furniture, the quality of the bass is largely determined by the speakers, with the analogue source and the amplification having some say in the matter too.
 
Well no, room modes are determined by the physical dimensions of the room, and every room will be affected to a greater or lesser extent depending upon the room’s ratios, construction and the loudspeakers bass extension.
Keith
 
Antifon said:
Thanks - that's another concern I had: how well does ATC make the transition from the largest sealed box design (SCM40) to the lowliest of the ported designs (SCM50) while still retaining their characteristic "house sound" (to use a term that many would probably dislike). Apologies if you've already said earlier and I missed it, but what did you end up buying?
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I bought the SCM50A classics. My experience of the transition from SCM40 to SCM50 is of significant "house sound" consistency with differences in the ways I expected. I liked the house sound from both but I preferred the latter.
 
Purité Audio said:
Well no, room modes are determined by the physical dimensions of the room, and every room will be affected to a greater or lesser extent depending upon the room’s ratios, construction and the loudspeakers bass extension.
Keith
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So you've gone from "entirely" to "greater or lesser".

However you still need to add a bit on the end: "and every room will be affected to a greater or lesser extent depending upon the room’s ratios, construction and the loudspeaker's bass extension and LF transient response."
 
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