Thanks Innocent_Bystander,
I read somewhere something similar to what you wrote (“trying to use to correct nulls caused be standing waves is a quick route to speaker destruction!”) and that has made me a bit nervous about playing around with EQ in Roon…
Fine to use it, just don’t boost anything by more than, say, 3dB (=double the amp power, so only half the headroom before clipping). And don’t expect all ills to be cured - but it nevertheless could make a positive difference if, for example, you have strong peaks or a very uneven response.
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Yes, there is a small window - 2ft by 3.5 ft and recessed - but it will have something against it in all likelihood. Just need to get to the shops now they are open to get things going.
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Thank you! Very useful advice.
I am not expecting miracles…but curious to hear what difference it makes.
Up date on my room … although i had 2 panels on my ceiling at the first reflection point , i did wonder about the effect the rest of the untreated ceiling was having.
During a discussion with Lukas @ GIK about the effect of adding more ceiling panels , he stated that adding extra panels above and slightly forward of the speakers would help reduce early reflections and that having some directly above the seating would impact the way you perceive the room.
So decided to give it a go and must say its worked out rather well , infact they have made more of a improvement than the first 2 panels.
Really made the room disappear to a much greater extent , so much so that i added some Alpha front plates to my rear Monster traps , after more discussion with Lukas , to further open the room up. Success all round.
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I’ve just bought a UMIK-1 and did some initial measurements. Right now the frequency response is the only graph I know how to interpret, so let’s start there I figure. As expected with my asymmetrical room I have some issues. The room is essentially an upside down U shape. The section the hifi is in is about 5mx5m with a 3.2m ceiling. The left speaker is in the corner (1m away) with large windows along the left wall. The right speaker is next to the opening, i.e. has no boundary on its right side. Front of speakers are 80cm from the back wall.
I don’t really want to move the left speaker further away from the corner, as that would bring the speakers closer together, and they’re already at 75% of the distance to my listening position.
Now regarding treatments, there’s not that many options. One thing I could possibly do is put a corner bass trap behind the left speaker. But the complication here is that on the side wall after about 32cm a window starts. Not sure if GIK or anyone could make a 31cm one? Seems theirs are 41cm and only the height is customisable.
Anyone knows of any other company that could do such a thing? Or has any other suggestions of course.
Hi n-lot, why don’t you send some photos to GIK UK and see, what Lucas can suggest/ offer. I would imagine any large absorber measurements can be tweaked to your needs. Remember to possibly allow for a 1-2 inch gap to side back wall, which allows for some air flow round the absorbers. 
Good luck Peter
To illustrate gap in my humble case.
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I seem to remember that GIK recommend straddling a corner with a panel . So you could use a Monster Bass Trap of 300mm width or even a 600mm wide one with a reduced angle.
That would then give you a helpful air gap. With your ceiling height you could also beneficially use a stacked pair.
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You should be able to find a shop that sells foam, rubber etc and get an acoustic foam that is 100mm or so think cut to size. I’ve done this with great results.
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At the bass end of the spectrum mineral wool is far more effective than foam. As GIK offer a free advice service I’d speak to them (no commitment to buy their panels): they can take and interpret REW files, which have a lot more info than just the frequency spectrum. Also best provide a sketch of the room and key furniture etc as well as speaker and listening positions, with measurements.
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I suspect that is in Europe only. I spend a few hours sending them a very detailed room measure and photos and didn’t even get a reply!
I suppose they might think there isn’t a realistic prospect of sales to the other side of the globe, though it seems bad them not responding and saying the free service os only local. Did you try sending a gentle prompting email after a week or two? I always do that with anything not having a response as I know how easy it is to overlook something when receiving large numbers of emails a day.
Certainly when I approached GIK 2 or 3 years ago they couldn’t have been more helpful.
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They actually have retailers here, so it was a bit odd not getting a response. In the end I’ve done some DIY treatments that I’m happy with, otherwise, yes, I’d do a follow up.
Hi, the biggest problem you have there isn’t the lower bass issues from the room modes, but the broad depression (almost certainly a cancellation null) centred around 300Hz. I believe this is what you need to fix first.
The good news is that it’s much easier to get absorbers to work in the 200-500Hz range, the down side is that getting the right position can’t be done just from the FR graph. Even with the early Impulse Response graph (0 to 0.02s) I won’t be able to tell you exactly where to put the absorption, but with that and a diagram of the room layout (including the height of the ceiling) I may be able to suggest some candidate positions.
After fixing this, we can try to sort out the ‘one note’ type boom from the left speaker.
Incidentally, why is the tweeter response set at -4dB?
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That might actually be bad news, as I don’t think I can domestically get away with much treatment, certainly if not tucked away in a corner. Possibly stuffing foam or rockwool behind a painting, inside the fraim. But then I have my doubts how much absorption that would really provide.
Could placement help with anything?
Ceiling is 320cm high, I’ll see if I can draw a diagram later.
Nothing is deliberately set. I wonder whether it’s because of speaker placement / tweeter axis. I’ll try toeing them in a little more and see what happens. Currently at (guessing) ~25 degrees
Placement - very much including listening position - can make a huge difference, and is always the best place to start. And that can include completely rethinking the orientation of the room. (In my own present room, which is the first in which I experienced serious sound problems, I ended up with a very different room layout - and far better sounding as a result, even though it still needs treatment.)
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Annoyingly the program I chose didn’t allow me to put furniture in (or at least not furniture that wasn’t a fixed size which happened to be nowhere near mine, so I’ll try to describe below)
The room is a bit unusual. The ceiling is 3.2m high all the way from the windows up to the right hand “room”, where it lowers to 240cm. The windows at the front are both 205x230cm (WxH).
The Hifi is in the front “room”. The listening position is a sofa against the “bottom” wall approx 240cm wide. There’s a floor to ceiling bookcase against the right hand wall. The “top” wall has a 228cm hanging sideboard exactly in the middle of the front bit (i.e. 137.5cm from the window) The speakers are on either side of it approx. 35cm away from it. Front baffle 80cm away from wall, so sticking out further than the sideboard. There’s a 2.5x3.5m viscose rug on the floor.
The layout is pretty fixed, i.e. speakers can be moved around and away from the wall, but that’s the “compromise”. Moving sofa’s, treating the ceiling etc. are not likely to fly with the rest of the household. But if any fairly inconspicuous treatment (like a corner bass trap behind the left speaker) could help I’ll be happy to bring it up.
Hope this helps.
For posting here it can be easier to sketch and photograph!
It might be worth describing (or better still drawing) the rest of the room layout and furniture etc, also any doorways. And perhaps clarify why anything particular is fixed (apart from genuine fixtures), other than because that is where it is now. And what are the other room uses?
Acoustically, that’s… well… um… complicated!
I’m working tonight so I’ll need time to think later, probably tomorrow.
I have returned to using DSP again to add the finishing touch. When I changed to smaller speakers last year to the Tabs it did help solve a lot of my problems and everything vastly improved over using the floor standers I had. The Tabs sounded great and I felt I didn’t need to use any DSP any more also i wanted them to run in.
I have optimised their position now but still felt the Room was adding in its own thing. It’s a lively room and I have no way of adding treatments. Been down this route already and the Mrs outright refused any. I dont blame her as they are just not fitting for a living space if you ask me.
So even with the Tabs I still had a bass bump at certain frequencies that was noticeable and a slight null at around 200hz and the bass overall was not always present. Yes they are a small speaker but they are very capable.
So I finally decided to redo my measurements and send them back off to Home Audio Fidelity to get some updated filters to use in Roon( can be used in most software that supports DSP) for the tabs. They have their own measurement software now so no need for REW and it’s far simpler and easier to setup and use.
Got my new filters back within a few hours and wow just the icing on the cake. The vocals and midrange which are the. Tabs strong point are just so much better, more focused centre and so much clearer. Bass is so much fuller across the spectrum and treble is just lovely it’s lost any hint of glare and reverb that the room added. Overall a much more balanced affair and no drawbacks to me.
His service is unique for DSP and offer these that other systems just don’t touch.
- Combination of room/loudspeaker correction (inc. phase/timing) & acoustic crosstalk reduction
- Specific handling of direct and reverberated sound
- Temporal management of resonances with Room Shaper plugin
If you can’t use treatments I strongly recommend you look at this as an alternative. DSP has come on leaps and bounds. I know lots of users of HAF not one has gone back to no DSP when they hear the filters in use in their systems it makes that much of a difference for very little outlay and hassle. If t doesnt work for you you don’t pay or you ask him to tweak it until you do.
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