The Listening Room Reality

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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I’m really confused now. I was playing with speaker position, and now I seem to have much less issues in the lower end of the spectrum, but a massive spike at 9kHz. Even when I put them back in their original position!! (I had used tape to mask the location, so sure it’s correct)

I don’t think much changed in my room, so not sure what it could be. Don’t assume the exact location of a small sidetable will make such a difference. Perhaps because I used Bluetooth for the sweep? I’m at a loss. Giving up for tonight, will try again at the weekend.

Did you get the same 9KHz +20db peak on each of channels when measured independently?
Does it only occur when both channels are measured together?

It’s worth trying doing the measurements again (L, R, L&R) without the side table, it could be due to something resonant associated with the table.

Oh yes, the beauty of measuring… :crazy_face:

I would be worried about getting 2 so different readouts from just having tweaked the speaker positioning slightly. :thinking:

Are you speakers set up with equal distance to the sidewalls and what are you actually hearing from your replay, if the 20 Db lift at 9 K Hz has cropped up out the blue please? ATB Peter

In more general terms I can’t really see the purpose of trying to get your head around measuring and the fretting, which invariably goes with it. You are only ‘allowed’ one single acoustic panel why bother?
Speaker positioning and listening position is surely something done ‘by ear’, with the possible domestic restraints, that it seems you will have to adhere to. Hence finding the best compromise without having to wear a hard hat. :face_with_head_bandage: Peter

I had it on all three measurements, L, R and L+R. Also the other issues on the previous measurement are much less, the big null for example is completely gone. It’s a really small table, I doubt it would have any such significant effect, but will try without.

The previous measurements had been repeated on multiple occasions, so I know they weren’t a one-off. I’ll try again over the weekend and see what happens.

I’ll also pick up my AMB gamma2 DAC to use as a USB → S/PDIF converter to exclude bluetooth doing something silly with the REW signal.

I don’t think it’s from the movment, because as mentioned when moving the speakers back (position had been marked with masking tape), the measurements were still very different from the originals.

No, the room is an irregular shape. The right speaker has no sidewall boundary. See a few posts back for a plan and description of my room.

Interest really. I understand why you wouldn’t bother, but I find it interesting, even though I except it won’t be perfect. And hey, maybe a (small) improvement can be found within my constraints. Who knows?

Sorry n-lot, must read more focused. Well as discussed earlier the only thing you can really do is to stick a tweaked monster bass trap ( ie thicker than standard) in you top left corner on your computer generated diagram and get the prayer mat out :wink: Best Peter

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Another thought on that HF peak…

I assume you did have the curtains over the windows in the same position this time.

I actually thought of that at the time. I couldn’t remember the curtain situation in the original measurements. But measuring with them closed or open didn’t seem to make any difference in the grand scheme of things (didn’t look in detail as concerned about the peak / difference with previous measurements)

Suddenly something occurred to me. I needed to get the microphone up to ear height. The first time I used a stack of (empty) boxes, this last time a stack of magazines. I can imagine these would actually have a very different effect acoustically. Probably much more than a small side table.

Perhaps that can explain the different measurements.

Indeed! In fact need to put the microphone where your ears would be in the listening position - same height, same distance from whatever is behind whether that is a chair headrest or the wall, etc. And ideally take multiple measurements around the various positions they would be in, averaging the response, as you not only have two ears but unless strapped rigidly against the chair your ears will be in slightly different positions at different times, and at the treble end just a few centimetres can make a big difference. If your mic positin was significantly different in any direction between the two occasions above that might well account for the differences.

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Mic position was the same every time, at ear height in my listening position.

But there was a (big) difference in the objects I used to get it up to that height. Empty boxes vs (glossy) magazines.

Is there any recommendation on what to use? I guess something most similar to your body as that will have an effect as well.