Digital room correction – My experience - Home Audio Fidelity

Audio Gear Talk
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I have been using convolution filters for some time now with my IEM’s and I am quite happy with the result - Thanks @killdozer

So, I thought why not do the same on the main setup:

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There are many interesting options regarding room correction. But some of them are not that easy to understand, at least not for me :blush:

But then I did get a very nice tip from @Kuryan_Thomas (Thanks) that sounded easy to measure and implement.

So, after buying a miniDSP UMIK-1 I contacted Home Audio Fidelity in France.

The next step was to take the 9 recommended measurements, the first at the main listening position and 8 more 30-60cm around the sweet spot.

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I saved these and sent them to Home Audio Fidelity including 3 tracks. That was easy. Now I just have to wait for the convolution filters.

But no - Home Audio Fidelity did get back to me quite fast:

“Having a closer look, I found out that you have a polarity inversion b/w your speakers: could you please double check your external cabling?”

Wow :blush: That was the case. A week before I had unplugged all speaker cables but did not connect then the right way again :blush:

So, I had to do all measurements over again :blush:

I received the 3 tracks back: The modified versions : a_mod version corresponding to the standard correction and the _mod_xtalk which has crosstalk reduction on top (generic model).

Did some testing but it was very hard to hear a difference compared to the original tracks. A small improvement in SQ with the crosstalk version. A bit strange.

I realised that perhaps I hadn’t chosen the best track to test the full capabilities of the process.

But then I thought, let’s spend the 159 EURO on the full-blown version. If there would be no improvement, than it would be sunk cost.

Well, the filters arrived quickly after payment.

It’s certainly different to any other “upgrade” that I have done.

Initial findings are positive with the crosstalk filter. Instruments are clearer and more defined – a better soundstage.

I will be listening to a wide variety of music this WE and then report back and see what tweaking may be needed. If any!

So still work to do.

Have a nice WE

Torben

PS: Still having trouble to understand the difference:

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Been the best money I spent on hifi in years.

Thierry is so responsive and willing to tweak the filters.

Mind you after getting 2 tweaked sets from him I find I mainly listen to his original one.

In my room it’s the equivalent of a focus ring on a camera, particularly with high frequency percussion.

I now recommend to anyone (that will listen) before you consider any upgrades particularly a cable upgrade - get these filters.

.sjb

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He’s smoothed the bass out a little in the mids and the slight bump at the higher end to roll off smoother. It will be subtle, less is more in DSP.

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:dove:
Really don’t want to sound condescending, so please don’t get me wrong, but…
… if you fired up the system afterwards and didn’t instantly hear that problem, how could you possibly be able to tell the, miniscule at best, effects of those tweaks you wrote about in the past?

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LOL :slight_smile: I didn’t :slight_smile: Hard to do that when you not a home.

Torben

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I absolutely believe these filter settings are bringing some improvement and I am far from giving a verdict without having listened to music in this room. But to me the combination of pictures plus measurements is strongly hinting to the conclusion that the first things to do is improving speaker positioning and room acoustics, not finding EQ settings to counter what the room is doing to the sound.

The main things I read from the measurements: It seems you are facing severe problems with resonances and standing waves all over the bass region from 25 to 150Hz. Several peaks of such significance plus some dips are usually indicating problems in the time domain plus cancellation effects you both simply cannot EQ. You can milden the problems but not solve them digitally.

The other thing I noticed is that the increasing level in the treble region >5k has been corrected. That might milden problems with sharpness and ´metallic-sounding´ reverb but again it is not solving the problem. The problem is you have too much energy in the room in this region and too less in the area 2k-5k. You need absorbtion to solve this, not an EQ. Are the B&W all D3 generation?

I See you using the Linn Selekt in 4.0 surround mode, is that correct? Are you happy with that setup?

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I do agree with @Arindal. Your room is very beautiful, but it has hard surfaces such as glass and hard floors that will reflect sound and cause dips and peaks in the frequency response.

It’s really a matter of priority: do you maximize the sound quality or do you make the room attractive and pleasant to occupy? In my case, when I built my house, I had the architect design a listening room or theater for me in the basement. No windows, and dimensions were chosen to minimize standing waves. After construction, I put acoustic treatments in the room: walls, corners, and ceiling, plus wall to wall carpeting. It’s not a room I would want to live in for days at a time, but when I want to listen to music or watch a movie, the acoustics are excellent, and Thierry’s filters improved things even more. It’s not an unpleasant room by any means, but the priority for the room is acoustics. Other rooms in the house are optimized as living spaces.

I don’t believe either approach is right or wrong. As I said, you prioritize and you proceed accordingly. Thierry’s filters will definitely make the sound as good as possible, and as long as we are happy in our room listening to music, isn’t that the whole point? The original thread was about “OMG” moments, if you listen and you say OMG, then it’s a success!

I’m happy to hear that you got improvement from the filters; here’s to many hours of enjoying audio and video!

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I am using Linn Selekt in 5.0 surround mode – but only for movies.

Yes – all 5 of them are D3.

Torben

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THX @Arindal + @Kuryan_Thomas for your great comments - highly appreciated.

I know that the hard surfaces such as glass and hard floors will reflect sound and cause dips and peaks in the frequency response.

And yes room acoustics would lift the SQ even higher. BUT - I has to look good at the same time - and that is not easy to find. Placing absorber in the ceiling could an idea - but if this bring the impact is hard for me to say.

Have a nice WE

Torben

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You nailed the acoustic problem @Kuryan but I would not go so far to declare a compromise impossible. It is just in my opinion the combination of obviously significant reverb in the room, speaker placement close to the wall and fairly large distance to the listener plus choice of loudspeakers being known for substantial low bass and wide directivity pattern in the treble region - that is a recipe for acoustical problems being absolutely ´un-EQ-able´.

Whenever I have heard convincing sound quality from the B&W 80x D3 (and they can offer world-class treble resolution!) it always turned out that the room had been damped heavily such as in a home theater environment. That is certainly not the case here.

I would not dare to judge from afar but the typical effects can clearly be seen in the graphs.

Standard measures to improve things would be:

  • moving main speakers away from the wall and the zones causing resonances
  • moving main speakers closer to the listener
  • applying a decent amount of absorption such as designated damping curtains
  • if speakers would ever be exchanged, go for something specifically focussing the sound waves evenly and causing the minimum of bass resonances
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Definitely, I absolutely agree a compromise is possible. I only mean that what level of compromise is acceptable becomes a personal decision.

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I agree that DSP cannot solve everything, but I don’t believe treating the room can either, unless it’s in a dedicated room. Sure some small things!

Treatment the living room will be limited. I mentioned to my wife, that I was looking at putting bass traps in the corners, designated damping curtains and panels on the ceiling, she just gave me THE look and a comment that “it’s not a recording studio”. I think this was a no go :slight_smile:

I still listening to a wide variety of music. I will be back :slight_smile:

Torben

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You are absolutely right. But even if you could treatments for bass are often really not that effective in the end your rooms a fixed size and you can only do so much for certain frequencies without it being purpose built or a recording studio you don’t live in.

Yes we could all move speakers and listening position to the best place in the room but it would not make it practical at all for 99% of people or families. We adjust as good as we can to make things work. DSP does the rest. It solves my bass issues none of which I could without DSP and I have tried with many different speakers always the same. There is too much naysaying on DSP in audiophile circles and they really are missing out on what their system could actually sound like.

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Roon makes it easy to do comparison. Save each filter as a pre-set:

  • Without filter (No DSP)
  • With room correction filters (DSP HAF)
  • With filters combining room correction and crosstalk reduction (DSP HAF Crosstalk)

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Torben

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We all agree that DSPs are useful and people who dismiss using one in most of cases have to live with acoustical problems which could be solved easily. In my eyes the opposite belief that a DSP can solve everything is just as unhealthy as it in many cases leads to carelessness when choosing and positioning speakers.

The point about DSP is understanding what they cannot do. In other words: You have to create a proper base by avoiding problems in the time domain (such as bass booming and too much of reflexions at the listening position) which cannot be solved electronically. In most cases this means improving speaker positioning, choice of speakers and overall level of reflections/reverb in the room.

It is fully understood that no-one wants to live in a recording studio environment. But in many cases room optimization as a base for EQable reproduction means measures such as moving your speakers 50cm towards the listener, away from the corner, angling them in, choosing a slightly bigger carpet and maybe exchanging curtains in front of the windows. These 5 things together with choosing suitable speakers in terms of directivity after knowing your RT60 and acting accordingly in my experience solves more than 90% of all problems.

As a rule of thumb I would recommend to narrow down the listening distance to a level you get a ´center channel grade´ localization in stereo. Plus optimizing positioning and choice of speakers until dips do not exceed -5dB and peaks are not audible in the time domain (i.e. booming bass). Yes that sometimes means pushing a sofa towards the speakers or getting one out of the corner. But in most cases this is a pretty good base for starting the digital optimization.

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No one here has says it fixes all. It does howeve tend improve it through in most cases. You seem to miss the point that most will have already done as much optimising as we can. I don’t know a person into any Hifi that hasn’t played with speaker position . My partner is so fed up with me moving mine. But in most homes and I know mine it doesn’t really help enough as it’s limited to where they can go . Toeing in is as all I can do, to avoid first reflections and I am limited to get the best distance from the front wall as I can that doesn’t obstruct.

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Hej Torben. Jeg kan se at du også bruger room correction, har du evtl overvejet en Lyngdorf TDAI1120 forstærker med RoomPerfect? Jeg er sikker på at den falder mere i din kones smag end alverdens bass-traps i hjørner og lofter ha ha… De bedste hilsener Kurt :smile:

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I do not miss the point but have actually experienced many times that people do not put their effort into what is really solution-oriented in terms of choosing equipment. Many also do not evaluate the sound of speakers they are going to buy in their own room. In my opinion the single most crucial mistake leading to a lot of dissatisfaction and everlasting quest for new gear.

Yes hi-fi people tend to alter the position of their speakers a lot and angle them in and out. And it might change things to the better or the worse depending on the music played, no-one knows. But that is not changing the actual problems caused by the room and not what I would call a strategy.

For me a strategy is to first take an RT60 measurement of the room and then theoretically plus practically figure out what is the ideal (maximum) distance between speakers and listener by doing a quick monaural/localization test. If this already leads to an unsolvable contradiction (and it does in many cases), speakers have to be exchanged for an acoustically suiting model.

Again: Before you have achieved a sharp ´center channel grade´ stereo localization and eliminated annoying booming and cancellation of bass regions, there is no point in starting any DSP or EQ action or investing into it. That is also true to all the sophisticated room correction systems such as Trinov, Dirac, Lyngdorf , YPAO and alike.

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I think we all agree you can’t make a silk purse out of a sow’s ear.

When you say

do you mean by trial and error or are there speaker measurements that one can use to signify what speaker might sound best?

Also, it is worth noting that Thierry’s filters are not just computer generated REW ones – Thierry strikes me like the Jussi of DSP and is at the forefront of what this very technology can do.

.sjb

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Again I disagree with you. You’re just making assumptions of how we do stuff. I tested speakers at dealer then at home. I measured with rew where the best position is, but the fact remains I can’t have my speakers in that place or anywhere near it as it’s not practical in any way. You beating a drum that most of us can’t hear as it’s just not physically possible to do this in our spaces. If you’re lucky enough to have freedom to position where you like for both speakers and listening position and all the stuff in the room then lucky you, but you’re the minority. For most of us thats a pipe dream and we make the best of what we can. So let’s just leave it here please.

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