Mix Room Acoustic Treatment - Let the fun (again) begin.. Update #12

roberty

grappagreen said:

roberty said:

That looks super flat @grappagreen nice one 

I used REW and a MiniDSP to set up room correction in my listening room and the results were quite spectacular

Thanks..

Did you use Rephase as part of the process to tackle time domain after working in REW? Are you deploying FIR filters or just exporting EQ from REW into MiniDSP?

If not and you want to take another step up in quality I can guide you to something that is well worth the effort! It's not as good as the tool I use for a number of reasons but you can do something similarish for free..

Si

That would be good mate. I just did EQs. I treated the room quite heavily to start with, the sound in there is very good now

grappagreen

roberty said:

grappagreen said:

roberty said:

That looks super flat @grappagreen nice one 

I used REW and a MiniDSP to set up room correction in my listening room and the results were quite spectacular

Thanks..

Did you use Rephase as part of the process to tackle time domain after working in REW? Are you deploying FIR filters or just exporting EQ from REW into MiniDSP?

If not and you want to take another step up in quality I can guide you to something that is well worth the effort! It's not as good as the tool I use for a number of reasons but you can do something similarish for free..

Si

That would be good mate. I just did EQs. I treated the room quite heavily to start with, the sound in there is very good now

Take a look at this and the playlist walking through the process..

https://www.youtube.com/watch?v=O65Y_7pUkSg&list=PLChqFga45IcGGojIToCucGnoJQiq1Yxi4&index=1

Si

robinbowes

I would have killed for tools like this 32 years ago:

grappagreen

robinbowes said:

I would have killed for tools like this 32 years ago:

Amazing..

You can talk us through the state of the art then and I can talk about the state of the art now

grappagreen

 Update 11a

Thought I'd take a couple of minutes to talk about the room correction stuff I referred to in my last update.

So, just in case anyone is a) actually reading this and b) actually interested, here's a very high level overview of what this means and some thoughts.

When we sit in the listening position we're hearing the speakers and the room. As we know the room is effecting what we hear. Modes mess with the lower frequencies and as we move up the frequency range modes influence less and reflections more. When we use acoustic treatment we try to reduce the influence of these things. Some stuff is easier to influence; decay times (harder as we go low in frequency) and early reflections are the easiest. We can influence the frequency response down to a certain point by reducing modal energy and reducing reflection energy. Worth bearing in mind that it's these two things that change a nice flat frequency response from the ideal to what we experience. 

So what does DSP do to help us. Once we get to a certain point it's almost impossible to remove modal energy and the influence of reflections. We either run out of space, money, will to live etc. and in the days of old that was all we could do; we had to live with it. Today however we have tools that can literally perform audio magic.

In it's most simple 'room correction' form DSP allows us to invert the things we don't want to happen and remove them from the audio stream that enters the speakers. By the time the sound has traveled to the ears (influenced still by the room) we get what we want. Imagine if some modal energy is boosting 60hz such that in the listening position it is 6db higher than the original signal. If we remove 6db at source then the modal boost will bring 60hz to 0db when it gets to our ears. We get a desired flat response at the listening position.

Simple EQ has been used to achieve some of these objectives in the past but it is a very blunt tool. It also has the disadvantage of impacting on signal phase. If we introduce a traditional filter we are effectively changing phase and that is problematic. The other issue with traditional EQ is that it is a very blunt tool. We are limited to the number of bands etc.

Let's say however that we could build a digital filter that had thousands of (or way more) EQ bands. Let's say this filter was also able to do this without phase changes. Let's say we could also do the opposite; change phase without changing frequency. The power would be enormous. Not only is this a reality today, but we can do it with very modest computing power. We can also do way, way more and actually create systems that are incredibly accurate.

So what's the catch? As per all basic economics textbooks - there's no such thing as a free lunch. One price we pay is in time. It takes time to do this processing. We can however work around this by creating filters that are uber-high quality for when we are critically listening and slightly lower quality for mixing (as an example) where instant feedback is required. We can switch between them in real-time depending on the task at hand and get all of the benefits and none of the disadvantages. The other issue is that DSP can't do anything to reduce decay time in our rooms (not strictly true, but too advanced for this post). We simply have to get these under control using acoustic treatment in one form or another.

I'll leave today with a last point. With power comes control. Obviously not everyone wants to learn some of this stuff. There are solutions for folks who want a 'point and shoot' experience but they're just not as powerful and the results less optimal.

Is all this effort worth it? Completely.. go and look at Update 10 again - this took me 30 minutes and is still nowhere near what will be achieved when I come to do it properly at the end. At that point I'll also define linear phase digital crossovers, time align everything perfectly and linearize the subs before doing the final correction piece.

There are folks who think that this sort of thing is cheating/less valid. I'll leave them to live in the past. Few of us have the hundreds of thousands of pounds it can take to build 'perfect' listening conditions but today we can get frighteningly close to this for a fraction of the cost. It's not lost on anyone who follows this sort of stuff that many speaker manufacturers are including some of this capability directly into their products. 

Si

grappagreen

Well it's been a while.. too many things going on in life.

We're nearly there.. so what's changed?

A few attempts with the steel plated panels resulted in little success, lots of frustration and a few quid thrown away.. nothing ventured nothing gained. I've conceded and I'll have a couple of PSI AVAA C214's with me shortly to sort out the only outstanding issue in relation to room modes ringing out a bit below 100hz. I've added a bit more absorption and some poly's to scatter a little more in the rear of the room.

I've also replaced some of my monitoring chain and have an RME UCX II driving everything. Works brilliantly with Totalmix and the ARC USB controller. Got it configured to replace my Drawmer and it's killer.

My last purchase will be a couple of ATC SCM20A SL mk 2's. The room is good enough to justify it now... 

Some charts for fun and once the last bits are in I'll redo the room correction filters and move on.

1/48 smoothing



1/3rd


RFZ perspective is pretty sweet as well (I still have one reflection to try and sort!). Target was -10db but we'll be at -20 so worked out brill.





Sounds rather nice..

Si

grappagreen

Can't imagine anyone's interested but after some messing this morning I sorted out the final reflection that was frustrating me.. ironically I'd made a couple of desk 'slopes' to try and redirect reflected energy from my desk away from me. Removing them gave me this.. seems like they were actually redirecting energy at me



So about as perfect as one could attain in a domestic room really..

Si

koneguitarist

I have a wooden garden office, that I am setting my studio up in. It’s 6.5 by 4m, sounds alright to me. Does it really matter matter if there is a bit of reflection, or are people trying to get studios totally flat sounding? 

grappagreen

koneguitarist said:

I have a wooden garden office, that I am setting my studio up in. It’s 6.5 by 4m, sounds alright to me. Does it really matter matter if there is a bit of reflection, or are people trying to get studios totally flat sounding? 

Hi,

That depends.. create a new thread if you want to discuss in more detail.

Si

Macca_25387

Any photos of the room after your final adjustments. Some context to the graphs. 

grappagreen

Macca_25387 said:

Any photos of the room after your final adjustments. Some context to the graphs. 

Will do..