SCM50A to SCM40A

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Re: SCM50A to SCM40A

Postby kifbe » Tue Oct 24, 2017 12:58 pm

Thanks for your message and suggestions, Darren.

I’m more than happy with the sound at the moment, but I will perhaps consider your DAC1 mods on a rainy day at some point in the future. However, I don’t particularly like the idea of bypassing the Benchmark’s volume pot and relying instead on the Touch’s variable output. For the present I am running the Readynas Duo with the pre-installed Squeezecentre disabled and have installed then latest LMS in its place. I am using the EDO app on the Touch as well as setting its volume output to 100%, controlling volume instead with the Benchmark’s volume pot.

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Re: SCM50A to SCM40A

Postby Brad Lunde » Thu Oct 26, 2017 6:35 pm

MattSPL wrote:Unfortunately I don’t have the luxury of choosing sub placement(my sub measures approximately 600mm square), but having them below the speakers means they will act as one large speaker.
I use a BSS fds334T to time align the speakers and sub at the moment and implement a hpf on the speakers, then my subs amp has built in dsp also. I measure everything with a minidsp umik-1 and REW software. I hope to build the second sub in the future.



Technically this works with one exception: your mains are processed with the BSS and the converters in the BSS dictate the sound of the mains. Our results with such processors (also the Linea and the Behringer) and is this penalty is not acceptable to just full range analog. I can clearly hear a degraded mains dues to old, poor performance or live sound level DAC's inside the processor. One way to test this is just run the mains full range through the processor and then disconnect it and run it analog. Every time I do this I heard a big difference. Especially in resolution, image and reverb tails, room sound, etc.

We got involved in this work due to testing the market and developing a DSP box for our Subwoofer Pros brand for recording studios. All the available processors make our ATC's (all models) sound significantly worse than without it. So we have developed a DSP box with a more recent chip that sounds much better than these live sound processors. It is far less detectable in the mains, but still, you can hear its different, but its close. We hope to ship it in Q1 2018. It will have 4 unique sub outputs as we are working on the distributed sub idea in small rooms for more even low end coverage. For example, buying 4 ATC c1 subs may indeed provide a more even room coverage (not louder, but more even with fewer hot spots) than one large sub. A single sub is the most difficult to place of all, as the room modes are excited and you have no way to sort it other than moving it around to find the least annoying spot. Two is better, 3 better yet, 4 usually does it. Also, always locate subs at different distances from walls and corners than the mains. I once a did a demo with the subs directly under the 25s on stands and a good friend of mine who designs studio rooms came and yelled at me! He said your mains and the sub should ALWAYS be different distances to the side walls to prevent exciting resonances/room modes in the area of response covered by both boxes. Of course! Duh!

The benefits of the HP/LP and delay on subs is needed, but the cost to the mains is not acceptable with 99% of the processors we've tested. On our TransAudio side we are trying to create a new one!

Brad
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Lone Mountain Audio, part of TransAudio Group
ATC Importers USA

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Re: SCM50A to SCM40A

Postby MattSPL » Thu Oct 26, 2017 11:37 pm

Hi Brad,

Thanks for the message.

I used a Tannoy TDX-1 before the BSS, but the Tannoy developed a fault.
It’s funny you mention the degradation of sound as when testing with the Tannoy in my system I couldn’t detect any difference in sound when running full range and a clear improvement when applying some filters to cut my rooms bass peaks as they were drowning the mids. Then applying a hpf further improved things. I’ve more resolution and ability to hear reverb tails in my system now than I’ve ever had, but this is definitely due in part to having eliminated bass boom in my room.
This is my living room, so acoustic treatment isn’t an option, so EQ was the only way.
I guess that in treated room or studio there might be some negative effects of adding one of these controllers, but in a Living room environment, any negatives are far outweighed by the positive effects.

Cheers
Matt
Sony BDP-S790 > Matrix Quattro Dac > Digidesign RM2's with SB Acoustics drivers > DIY Dayton Audio UM18-22 Sub

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Re: SCM50A to SCM40A

Postby Brad Lunde » Sat Oct 28, 2017 1:03 am

MattSPL wrote:Hi Brad,

Thanks for the message.

I used a Tannoy TDX-1 before the BSS, but the Tannoy developed a fault.
It’s funny you mention the degradation of sound as when testing with the Tannoy in my system I couldn’t detect any difference in sound when running full range and a clear improvement when applying some filters to cut my rooms bass peaks as they were drowning the mids. Then applying a hpf further improved things. I’ve more resolution and ability to hear reverb tails in my system now than I’ve ever had, but this is definitely due in part to having eliminated bass boom in my room.
This is my living room, so acoustic treatment isn’t an option, so EQ was the only way.
I guess that in treated room or studio there might be some negative effects of adding one of these controllers, but in a Living room environment, any negatives are far outweighed by the positive effects.

Cheers
Matt


Well I sure won't deny that, if you have eliminated larger issues things do appear to improve. MY situation is little different, in that I am trying to figure out how to use subs with delay in a studio where the engineer has listened to his speakers for 10 years in the exactly the same place they have always been 12-18 hours a day. These guys can hear differences is a console channel. SO applying any kind of DSP across mains is a "high risk maneuver" that is likely to be audible to the engineer. I believe we are getting closer to a box designed for subs that will sound very good across the mains.

Brad
Brad Lunde
Lone Mountain Audio, part of TransAudio Group
ATC Importers USA

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Re: SCM50A to SCM40A

Postby kifbe » Sat Oct 28, 2017 9:25 am

Back to the original topic, Matt! The 40As certainly don’t need a sub, at least not in my listening room. I was amazed at the bass quality these speakers manage to deliver as this was my main area of concern when moving down from the 50As.

BTW, Matt, when I was on this forum years ago I’m sure you had a pair of 50As, so what happened and why the departure from ATC?

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Re: SCM50A to SCM40A

Postby MattSPL » Sat Oct 28, 2017 1:11 pm

Brad Lunde wrote:
MattSPL wrote:Hi Brad,

Thanks for the message.

I used a Tannoy TDX-1 before the BSS, but the Tannoy developed a fault.
It’s funny you mention the degradation of sound as when testing with the Tannoy in my system I couldn’t detect any difference in sound when running full range and a clear improvement when applying some filters to cut my rooms bass peaks as they were drowning the mids. Then applying a hpf further improved things. I’ve more resolution and ability to hear reverb tails in my system now than I’ve ever had, but this is definitely due in part to having eliminated bass boom in my room.
This is my living room, so acoustic treatment isn’t an option, so EQ was the only way.
I guess that in treated room or studio there might be some negative effects of adding one of these controllers, but in a Living room environment, any negatives are far outweighed by the positive effects.

Cheers
Matt


Well I sure won't deny that, if you have eliminated larger issues things do appear to improve. MY situation is little different, in that I am trying to figure out how to use subs with delay in a studio where the engineer has listened to his speakers for 10 years in the exactly the same place they have always been 12-18 hours a day. These guys can hear differences is a console channel. SO applying any kind of DSP across mains is a "high risk maneuver" that is likely to be audible to the engineer. I believe we are getting closer to a box designed for subs that will sound very good across the mains.

Brad


I wish I had a treated, dedicated room. Maybe someday.
Keep us updated on the new EQ device please, it sounds interesting.

Cheers
Matt
Sony BDP-S790 > Matrix Quattro Dac > Digidesign RM2's with SB Acoustics drivers > DIY Dayton Audio UM18-22 Sub

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Re: SCM50A to SCM40A

Postby MattSPL » Sat Oct 28, 2017 1:51 pm

kifbe wrote:Back to the original topic, Matt! The 40As certainly don’t need a sub, at least not in my listening room. I was amazed at the bass quality these speakers manage to deliver as this was my main area of concern when moving down from the 50As.

BTW, Matt, when I was on this forum years ago I’m sure you had a pair of 50As, so what happened and why the departure from ATC?


Apologies for the thread derail Chris.

I did own scm19’s then 50asl’s then PA65’s. I sold the 50’s then later the 65’s in a process of downgrading.
I used the 50’s with a JL Audio f112, which was a great setup, but realistically needed room treatment or EQ for room mode problems. I think applying a hpf to the speakers somewhere between 25 and 35hz was needed to limit the sub bass at high SPL’s reaching the speakers. This is what I do now and this is also what you do when using a ported sub, because you risk overdriving the bass driver once below port tune.

The sealed PA65’s were better than the 50’s imo, except rolling off sooner in the bass. I didn’t have a sub with those, but they did need one. They were limitless in terms of SPL ability. If I had a dedicated room I would get some PA65’s and a pair of 24 inch subs.
Due to the PA65’s sealed enclosure, very deep bass didn’t phase them, they just rolled it off by design, this is why I think the scm40A’s will be great.

When looking for a smaller speaker after the 65’s I knew from owning PMC’s before that they were the way to go as they sound fuller at low volumes than most other speakers, although bass speed and detail isn’t up to the standard of ATC’s or other good sealed type speakers. I’ve kids now, so low level listening happens more than REAL volume levels.

I found these Digidesign rm2’s Used. They were made by PMC for Digidesign and are about the size of a PMC TB2i using a 4ohm version of the Vifa mid/bass.
One tweeter failed and a bass driver had a crease, so I contacted Digidesign (Avid) and PMC but no parts were available. So I searched for suitable replacements which led me to SB Acoustics. The Satori mid/bass was getting rave reviews on diy forums and could handle the 3khz crossover. SB Acoustics also did a tweeter that looks identical to the original tweeter, so fitted the baffle cutout.
These new drivers transformed my speakers into something the original drivers could never dream of. I now have ATC like mid clarity in a small speaker.

I always feel the need for a sub, regardless of the speaker, because when I can tell bass is rolling off in music, I need to hear all of it.
I had a velodyne DD12, but sold it and built my 18inch sub and bought a DJ amp with the funds from the Velodyne. I can now reproduce all the bass on any recording down to 5hz. This may sound crazy, but it’s part of the hobby for me and I search out electronic music that contains bass content below 20hz.
Also recreating the impact of a live amplified gig is part of my aim. Try Rodrigo y Gabriella live in Manchester and Dublin or Live in Japan and you get the physical force of the hand beats on the guitar, just like at their concert.

Cheers
Matt
Sony BDP-S790 > Matrix Quattro Dac > Digidesign RM2's with SB Acoustics drivers > DIY Dayton Audio UM18-22 Sub

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Re: SCM50A to SCM40A

Postby kifbe » Sun Oct 29, 2017 3:19 pm

Thanks for that detailed update, Matt, most of which I didn't understand! :D You obviously have very different objectives to mine and I hope you eventually achieve the bass quality you are searching for.


For my own part, I have always preferred the classic twin speaker approach and expect to get a really good sound from this combination alone, accepting that all music reproduction will always compromised and less than perfect. If I ever felt I needed really awesome bass I would buy a pair of 150As, which I've just noticed ATC now offer in satin white, so one of these days I might just do that!

Enjoy your music.

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Re: SCM50A to SCM40A

Postby Bulldog » Sun Mar 04, 2018 9:12 am

kifbe wrote:It’s about 5 years since I last posted on here, so HELLO to all those of you who still remember me.

Back then I had a pair of SCM50 ASTs in black lacquer... the speakers were in storage... I just couldn’t accommodate them in either my 8m x 5m lounge or my new 4m x 5m sun-room extension without them physically dominating their surroundings...

I know that on paper the specification of 50As and the 40As are quite different, but all I am telling you here is that in most respects I find the 40As sound very similar indeed to my earlier 50As (and at half the price!). I’m enjoying playing my music again and, try as I might with different albums, I haven’t yet found any reason to be disappointed.


I'm in the same position myself, I'll be moving soon and my old 50As are in storage as well. The new 40As are very appealing and I could nearly get into a pair if I sold the 50As and some other gear for the right price.

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Re: SCM50A to SCM40A

Postby kifbe » Tue Mar 06, 2018 9:18 am

Trust me, Bulldog, you will not be disappointed if you move over to the 40As. I have now enjoyed a full six months listening to mine and I have not changed my view that these are terrific speakers, and I certainly do not miss the old 50As. ATC have achieved an amazing synergy of components here and I believe that the elegantly curved cabinet shape has much to do with the resultant sonic performance.

If you do decide to make the change please let us know how get on.

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