Yes, I think you probably have the correct suggestion here. The active traps claim to be effective as something twenty five times bigger in passive form.
However - there is a subtlety - I suspect that it is the ratio of the equivalent absorption values at 32Hz and 63Hz (for the active trap) that will determine the successful modelling of such in Linn SO.
So the only spec for an active bass trap I found had values of the equivalent area of absorptive material, not actual absorption values. I guess what they mean might be an area whose absorption was total (1). After a bit of looking, that’s exactly what equivalent absorptive area means, seems that you might be able to use the plots of that provided by your active bass trap manufacturer of choice, to fill in values in SO. You’d have something like an area of the appropriate size with a value of 1 for absorption. It might not be the best way to model it in SO if the area of wall was large?
@Innocent_Bystander that’s exactly what I was trying to describe as well, badly it seems X)
Hi @gthack , yes, I think that would be the way to do it in Linn SO.
Full Disclosure: I believe it was me that came across the problem with the depth of acoustic panels in Linn SO along with some other limitations.
I have noted that extra warnings have been added into Linn SO Room Design software since I sent a couple of technical reports to Linn in Q3 last year.
You can see one of those new warnings in ORANGE text in the Custom Materials edit view in my previous posting.
Anyway, first reflection control and correct positioning of speakers is still required in your room if just using Active Bass traps.
The benefit of Linn SO is that you don’t even need to put your speakers in the right place! Although I don’t make use of that capability in my room.
And if just using Linn SO as the early reflections are most signifcant at mid/high frequencies not addressed by SO.
The other benefit of Linn SO, is that it gives some visibility into what is likely to be happening in your room.
It is not much visibility - limited to the real magnitude (I.e. not complex) amplitude vs frequency correction to be introduced to the music playback from each loudspeaker.
Here are examples to illustrate (L channel only shown) and Optimisation set to 100% to ‘flatten’ the frequency. In other words, Linn SO to make the phase vs frequency curve as linear as possible below 100Hz in room at listening position.
SO Room Correction Filter without Room Treatment ………
SO Room Correction filter with Room Treatment……..
For a less extreme example the following Optimisations are for Linn SO to give a bias of 55% to flat frequency and 45% towards shorter time impact (for corrective impulse response)….
SO room correction filter without room treatment……….
SO room correction filter including room treatment…….
Hi All,
For those following this thread there is an additional benefit of modelling the room using computational fluid dynamics (cf Linn Space Optimisation)……
A few days ago I mentioned that the HiFi dealer had demonstrated a Reference level sub bass for a few hours in my home.
With Linn SO, I can also model the room optimisation filters it will produce - before I actually buy any particular sub bass.
Here is a simulation I did for just such an evaluation…. (Optimisation bias is set to 100% flat frequency for this prediction)…….
The relevant comparison graph from the four above is the second one in the list. Ie SO on at 100% bias in treated room, but that comparison one of course is without sub bass in room.
OK, time for the next steps for acquiring a sub bass or two.
Having done all the scientific modelling, big question is which brand and where will it/they go in the room?
Luckily, I have some spare cardboard from a recent delivery of room treatments, so here are some potential ‘space models’ I prepared earlier placed in candidate positions……..
Will it/they be the Magico S series sub……
Or something better?………
Hi Edmund, are you able to arrange a loan, or do you have to commit and go in for the full transfer?
That will significantly improve the depth of your squad, certainly to the calibre of the existing line-up.
I bet the answer will be Magicos …
Hi @Middle , Have you - by chance - been ‘zooming’ into read the hand writing on the top and sides of the cardboard boxes?
It did bias the diagnosis …
Hi @Protegimus , Thank you very much for your complimentary observations regarding the team and line-up!
I suppose I could ask for a (home) transfer loan. I have done that in the past with sources or amplifiers and for brief moments also Magico loudspeakers (S1 vs S3) in 2019.
However, sub bass of this calibre from Magico are harder to find on loan, at least in the UK. My dealer has suggested a trip to Portugal where the UK importer/distributor also has a HiFi dealership business. It is that, or a trip to a warehouse in London somewhere, or a trip to California to the Magico demonstration room.
Faced with those options, what might you choose?
I would speak to those parties that can demo the subs and fins out about their demo rooms and what electronics they can demo with.
As a Magico owner going to their factory or main demo rooms will be extremely interesting for you.
Then you can decide.
Hi @Dan_M , good to hear from you again. Thanks for looking into this thread. I hope all is well with you, and that you are having a good time with the extra bass traps you ordered?
I had already had moderate go at trying to do what you suggest. Three other dealers came up in internet search from the one I use most (I.e. four in total). I have visited the well Known (Just slightly) West One HiFi dealer in London😉, expecting at least the SSub on demo, and hoping for perhaps the Magico Titan as well. Anyway, it was not a totally wasted trip as I got to see and feel the M7s which were on demo. But I went there for subs!
Anyway, must dash now, as - “I feel one of my turns coming on…..”
………
Rumours of new signing for ‘the back’ at E of E towers.
Speculation is circulating after a discarded ‘play strategy note’ and other information was found posted on a HiFi forum …….
When questioned, the manager would neither confirm or deny the potential new signing. Simply saying that the trials conducted in the previous month with members from other teams (REL and Wilson Benesch) had shown promise, but the All American star team of Magico is always one to look to - and their Subs understood the importance of controlling time delay, filter choice (cf phase and group delay characteristics), filter order (cf roll-off rates) as well as the usual parameters of gain and corner frequency.
Hi @Edmund-of-Essex,
I am very pleased with the monster bass traps behind the speakers. I think I am done for room treatment for the time being.
I have being building things up for a while now.
Vicoustic cinema rounds behind sofa and corner bass traps.
It’s a living room so has multiple purposes so havent’t gone whole hog with sides of rooms or ceiling as yet. I’m not sure I can go much further apart from doing the ceiling.
But I am glad to say that room treatment has been beneficial. I would certainly consider more in the future.
Bass is even more controlled with monster bass traps behind the speakers. Can play alot louder without distortion.
500DR does heat up with my Russian Techno. Part of me thinks I need a more powerful power amp! 
Nothing will be too much for Big Dan
Hi Dan, Thanks for these extra postings with more detail of your space and experience.
I noted a while back your treatment behind the listening position and thought your arrangement is most probably superior to what I have. This is because I have 20.5cm gaps between my GIK Acoustics Impression series panels with plain wall in between. If I tweak the toe in on the speakers too much they point to this gap and then I get something called ‘mode locking’, where peaks pop up in the amplitude response at the listening position at ~640Hz and ~960Hz. I am still thinking about what to do for this as the original room design I did was supposed to be aesthetically pleasing as well as having correct function.
Others forum members also use the Vicoustic cinema rounds behind as well I think - Cohen1263 for example.
Hi EoE, I’d be interested in your view of WB Torus/IG as it is one that from reviews ‘sounds’ great, though I’m not convinced that max SPL is adequate.
Hi @Innocent_Bystander , this could be a bit of a long read, but I’ll try to keep it succinct.
As a product concept, the design and specific implementation of the WB IGx seems very well thought out, with lots of advanced material and design approaches that should deliver significant benefits in the home.
First off, it is round like a drum, so one can ‘roll’ it into place.
Second, it has all the common control features of a sub bass for gain, variable corner frequency, variable phase and a phase control defeat switch so you can bypass phase control if you do not need it.
It also looks the part!
Unfortunately, for the version that I tried (which may have been an early prototype circulating amongst dealers) I had a number of issues which meant I never managed to successfully integrate it with my system. I had not expected to have it on loan as the dealer came in the morning and we all tried together to integrate it, but gave up late afternoon and they left me with the unit over the weekend to keep trying.
First problem was it had small holes drilled in the base. Don’t know why, maybe that was so they could get the 0.04% at 1W distortion spec?
Whatever, holes in subs do not help with integration!
The controls had no click or stepped markers (unlike REL which do) - this made it exceedingly difficult to conduct any repeat measurements.
The filter roll off is fourth order, not what I want with infinite baffle main speakers. But I guess they have matched the filter to their own range of loudspeakers for this aspect.
Next, the sub axis fires sound vertically. This is necessary because their construction architecture uses gravity as a way of solving lots of issues with conventionally constructed subs. However, even though this might not really be a problem in theory, in practice it was.
Finally, this wonderful concept of getting away with a smaller amplifier and motor, driving a very large, very stiff, very low mass diaphragm completely omits the fundamental fact that air has mass too. And if you want to accurately move and control a large volume of air at very low frequencies, you just need a bigger motor!
Of course, in other (untreated) rooms, with different main loudspeakers (ported) the results could be quite different.
Hope the above gives you the information you were looking for?
