ATC SCM 19 (Curved) & Super Lumina Speaker Cable upgrade

Peakman posted:

4)  the 272, even bare, is bloody good.

Roger

Hi Peakman

Sure is 

All the best

Rick @ Musicraft

Musicraft (Derby) posted:

Innocent Bystander posted:

the SM75-150 midrange unit in the 50 (same unit in model 40 upwards), 

Hi I B

SCM50's use the Super SM75-150S whereas SCM40's use the original SM75-150.

All the best

Rick @ Musicraft

Yes - however IIRC from when they marketed the drivers by retail, according to ATC the only differences between the two is greater sensitivity and higher power power habpndling capacity.

I seem to recall Jason Kennedy of hifi+ stating the combination of 272 with 40 actives was the best two box system he's ever heard.

If the 19A and 40A would go hard against the wall they would have been an option for me. But unfortunately, out from the wall, they are a non-starter. Coupled with a 272 or other suitable source, they are a wonderfully elegant solution. I remember reading that review and yes, it was very positive. 

My Dynaudio XD 600s are a sealed box design,so work good near walls...but I have never tried them right up against a wall.Fed from my 272,or Core directly,they are wonderful!They even have DSP settings you can adjust when closer to walls.

HH - I have my Passive 19's within 6 inches of the rear wall with no problems with the bass at all, as they are a sealed design. I'm sure the active versions could work in a similar position with no problems, although I've yet to try them myself.

Russt posted:

HH - I have my Passive 19's within 6 inches of the rear wall with no problems with the bass at all, as they are a sealed design. I'm sure the active versions could work in a similar position with no problems, although I've yet to try them myself.

It is not just rear ports that may cause problems in close proximity to walls, but the presence of a wall behind any speaker modifies the response, the effect varying with the distance, and the relationship in a roon is complex - so unless the speakers have been designed for locating against the wall they may not sound right. However, as the rest of the room also has an effect, there are no simple hard-and-fast rules, and sometimes speakers can sound right even when simplistic rules say they shouldn't.

In recording studios the well-rocognised solution to wall proximity effect is to mount speakers in the wall, with front surface flush with the wall. I do wonder why that approach does not crop up in hifi circles - obviously people's opportunities to do that will be very much limited, but the only time I recall it was decades ago with in-built concrete horns, which is rather a different subject. So, maybe if someone has an over-large listening room, try building a false wall In which to place the speakers...  Actually, for some people this can be tried relatively easily and readily revertable if not liked: I've seen some contributors' system pictures with a solid wall of books or records, but with the speakers in front or elsewhere. It would be relatively simple to rearrange/reconstruct bookcases/ shelving around the speakers, front edge aligned with front baffle of the speakers, filled with the books and records approximately flush with the front of the shelving (some unevenness is actually good for higher frequency scattering). 

Hungryhalibut posted:

If the 19A and 40A would go hard against the wall they would have been an option for me. But unfortunately, out from the wall, they are a non-starter. Coupled with a 272 or other suitable source, they are a wonderfully elegant solution. I remember reading that review and yes, it was very positive. 

I don’t understand why they shouldn’t work at least as good as any other speakers against the wall as they are sealed and fire from the front. Sound travels the same no matter what the speaker. I guess the issue is bass and how it interacts with the room. A limited range speaker with reduced bass may work better closer to wall. No harm in trying!

Halloween Man posted:

Hungryhalibut posted:

If the 19A and 40A would go hard against the wall they would have been an option for me. But unfortunately, out from the wall, they are a non-starter. Coupled with a 272 or other suitable source, they are a wonderfully elegant solution. I remember reading that review and yes, it was very positive. 

I don’t understand why they shouldn’t work at least as good as any other speakers against the wall as they are sealed and fire from the front. Sound travels the same no matter what the speaker. I guess the issue is bass and how it interacts with the room. A limited range speaker with reduced bass may work better closer to wall. No harm in trying!

The effects are at the bass end. Bass is not directional and radiates backwards around the speaker almost as much as to the front even with no rear port, so reflects off the wall behind the speaker, You get cancellation of the frequency where the speaker front face to wall distance is 1/4 wavelength (and 3/4, 5/4 etc, though the effect reduces with increasing frequency as the sound becomes more directional, not radiating backwards as much). At the same time you get a boundary reinforcement at other frequencies as the wavelengths reflected from behind add to the energy coming direct. The result can be a general bass boost but for a sharp dip, and the speaker gets closer to the wall the bass boost increases, while the frequency of the cancellation dip increases. The effects depend also on the other room dimensions and degree of absorption or otherwise of its surfaces.

Whether the bass boost very close to a wall is good or not depends on the speaker design - it is possible to design in a speaker response that relies on the wall proximity effect, though it may not necessarily compensate exactly as rooms differ. Such speakers do not sound right away from the wall, and as a consequence tend to have less flexibility of placement. (The SL2 is an example of a speaker designed for that wall effect.)

when you say a

Innocent Bystander posted:

Halloween Man posted:

Hungryhalibut posted:

If the 19A and 40A would go hard against the wall they would have been an option for me. But unfortunately, out from the wall, they are a non-starter. Coupled with a 272 or other suitable source, they are a wonderfully elegant solution. I remember reading that review and yes, it was very positive. 

I don’t understand why they shouldn’t work at least as good as any other speakers against the wall as they are sealed and fire from the front. Sound travels the same no matter what the speaker. I guess the issue is bass and how it interacts with the room. A limited range speaker with reduced bass may work better closer to wall. No harm in trying!

it is possible to design in a speaker response that relies on the wall proximity effect, though it may not necessarily compensate exactly as rooms differ.

Don't these speakers simply generate less bass to balance the bass boost due to being placed up against a wall? Or is it more complicated?

Essentially yes, that is my understanding,  presumably with the response curve 'shaped' to exactly compensate, by appropriate filtering. You could do yourself with a speaker yourself not designed for close wall proximity using DSP and a measuring tool like REW and a microphone, though that means extra circuitry unless already present, e.g either as part of the DAC or a digital active crossover - and maybe the active ATCs might have such capability built in.

Basically you could just audition your way down the ATC range until the bass sounded the most balanced. At the end of the day no room or speaker position is likely to be perfect.

i have speakers 1m from back and still have a bass hump between 40-50hz. Roon 64 bit floating point eq is ideal at cutting bass heavy tracks using a high pass filter before being sent to dac.

I think back to the wall on even the smallest ATC without equalisation may place undue boost in the upper bass (assuming they're not designed for against-wall use)

Being a sealed design they are already a foot off the back wall (speaker depth is 30cm) so that will help. I'd say a minimum of 20cm space at the back would provide an acceptable response, providing they are well away from corners.

As I said before no room is perfect so you're never going to get a flat response no matter where you put them. It's about compromise. To some a bass boost will sound great 

I use REW and a microphone to sort out speaker and listening positions, its objectiveness perfect for assessing the actual effect of moving speakers in and out (of course, if it sounds better then pushed a bit one way, then that is fine!

Yes, I've been down that route. I've learned the hard way just to use my ears and personal preference. I've also accepted that I'll never have a perfect room or setup and appreciate what I have.

Interesting - I found REW pretty good: the optimised position it found for my speakers sounds about right, but it would gave taken a lot longer by ear, and maybe even then been more of a compromise.

REW was very good. The problem was practicalities, I am limited where I can position speakers and listening chair, together faulty acoustic treatment (RPG modex plates).

Russt posted:

Simon - thanks for the info on your stands etc much appreciated.

Roger - I really enjoyed reading about your experience with ATC so far and would love to hear your opinions on the comparison between the active 19's & active 40's if and when you get a chance to audition ideally in your home environment.

Hi Russt

I intend to shop-audition the active 40s vs the 19s, but I'm very busy at the moment, so it will be a few weeks before I can do this.  I think I'll then ask for a home trial of either the 19s or 40s (they're heavy beasts, so I think it would only be reasonable to ask to try one of them.)  Then the big issues will be how well they work in my modestly sized (4m x 6m) room and whether the extreme clarity they provide could be tiring in the long run as against the slightly softer presentation of the 250DR/PMC Facts.  I'll post again when I've done the listening, but it won't be immediately.

Roger 

Halloween Man posted:

I seem to recall Jason Kennedy of hifi+ stating the combination of 272 with 40 actives was the best two box system he's ever heard.

He also states at the beginning of his review that the idea for the combination came from Salisbury!

Roger

Very interesting thread. I have quite a similar journey from PMC to ATC. I used to have PMC GB1i which was upgraded to 20.23. Then after few years I read about ATC SCM40MkII and superb reviews they got. I had to audition them myself and there was no return after that. I have quite a modest setup with Naim DAC + SN2 and back then HCDR but now replaced by aftermarket PSU. I've later also added aftermarket PSU to Naim DAC.

About SCM40 vs 20.23, simply no contest. First of all, SCM40 is much bigger speaker and you can hear it. Bass hits much deeper with strength and authority. This came apparent especially after PSU-upgrades to DAC and SN2. Midrange... after SCM40 you wonder if 20.23 even have one. This is ATC's biggest strenght IMO. Three way design with the stunning midrange driver really works wonders. SCM40 also sounds faster and better controlled than 20.23. The closed design helps to keep bass in perfect control. SN2 works surprisingly well with them but definitely needs PSU upgrade. Bare SN2 doesn't have the grip to drive these. I haven't compared these with 25-series of PMC though. I'd say that SCM40 would be a fair comparison against 20.26 or 25.26.

Someone wrote earlier that these might not work close to wall. Well mine are 15cm from the back wall and while there's is strong bass, it never gets out of control or overpowering.

Question for the op: Have you changed the jumper plates to something better on your 19's? I use NACA5 and cut short runs of it to replace the jumper plates.

Hi Roger it might be interesting to know that I too came from PMC 20.23 (great speakers btw) and actually found 40s more forgiving and a better match for my room. I also auditioned PMC 20.26 and loved them but just had way to much bass for my room. The 40s do have a little too much bass for my approx 4m X 4.3m room. 19s were a perfect match for my room but I just couldn't live without the sound of the 40s after hearing them both side by side in the room. I fire speakers down the short length of room, 1m from back wall to front of speaker, just over 2m apart (tweeter to tweeter), and 0.7cm from side walls, listening about 2.7m away. The further away from walls the better.

Home audition is a must.

Roger - I look forward to hearing about your experiences with the active versions.

Patu - Yes, I've currently got Tellurium Q Black jumper leads which were an improvement over the jumper plates. I've also got some NAC A5 jumper leads somewhere which I could compare with the Tellurium to see which works best with the Super Lumina.