Thanks a lot Juhazi.. 
Aalto University has been on my Radar for quite some time now especially because of the reasons you pointed out (Signal processing and audio).. In addition to it, some of mine and my wife's batchmates in academia are still there/have done their masters degrees there and I have heard good things from them..
The Oulu offer was very convenient since it was sort of like a family package.. Post doctoral fellowship offers for both my wife (who too has done her PhD in wireless comm. and is currently working in R&D at the same company as mine) and me in the same lab... And the professor is a big shot in our area of research..
Anyway, I will seriously consider this new career option soon, in an year's time or so..
Regards
Vineeth
Aalto University has been on my Radar for quite some time now especially because of the reasons you pointed out (Signal processing and audio)..
In addition to it, some of mine and my wife's batchmates in academia are still there/have done their masters degrees there and I have heard good things from them.. The Oulu offer was very convenient since it was sort of like a family package..
Post doctoral fellowship offers for both my wife (who too has done her PhD in wireless comm. and is currently working in R&D at the same company as mine) and me in the same lab... And the professor is a big shot in our area of research.. Anyway, I will seriously consider this new career option soon, in an year's time or so..
Regards
Vineeth
Today's system under evaluation
First impressions: Sort of slightly "relaxed" overall than my previous 2 way horn configuration. Placement of instruments, vocals etc within the soundstage is a little less clear than before.. In the horn system, it can be easily identified to sort of different points in space. In this one, that definition is sort of blurred..
Maybe for longer listening sessions, this will be easier to listen to I guess..
But I like both.. This is getting really hard..
First impressions: Sort of slightly "relaxed" overall than my previous 2 way horn configuration. Placement of instruments, vocals etc within the soundstage is a little less clear than before.. In the horn system, it can be easily identified to sort of different points in space. In this one, that definition is sort of blurred..
Maybe for longer listening sessions, this will be easier to listen to I guess..
But I like both..
This is getting really hard.. 
Not yet..
But I just took measurements at my ear height (on tweeter axis) from my listening position about 2+m away near the sofa. This is how it looked for both speakers
Then I allowed REW to make some auto correction.. The result was this
Now, in the coming days, I need to learn spatial averaging via MMM and how much better I can do with better room correction and read all the threads that fluid and others have pointed out..
Now, in the coming days, I need to learn spatial averaging via MMM and how much better I can do with better room correction and read all the threads that fluid and others have pointed out..
This is an old method but I that I’ve been doing for some time pre Dirac Live which I started using in 2015 to speed it up in all the rooms or studios I visited. But but never had e to document.
This is one of those things where video / visual teaching is at its best- Charlie Sprinkle ex JBL now Kali Audio demonstrated it to great effect here:
Best thing is that you already have all the equipment you need; give it a go when free.
Post #824 - I think that you used too much eq for taming 65Hz peak and level below 300Hz. Mode peaks need high Q eq but only ½ of the peak spl. In my experience after taming the lowest mode, just use your ears to set the bass tilt and level so that it is pleasing and natural at your typical listening spl. Room is the king and eq'ing response too smooth and flat doesn't sound natural. Multipoint measurements and listening at various spots are needed, but listening must be the final judge! Learning to do room EQ needs practise and even some radical settings for education.
Recession just above 100Hz is typically because of the vertical mode, ears/mic are too close to mid of height...
Room's reflectiveness can be seen from REW measurements from listening spot, by RT60 and Clarity analyses. They give absolute values and graphic presentation, but one must have measuements from different rooms to interprete them. Wavelet spectrogram is what I look at first nowdays. Eq doesn't help, only acoustic treatment!
DSP, Audacity, Dirac etc. with forum discussions showing measurements have made room EQ too technical and people don't trust their ears anymore... And personal preferences are allowed too! We get accustomed to a room's acoustics quite soon, if it is not extreme. A smallish room (smallest dimension less than 4m) has very problematic modes and positioning alternatives are minimal regarding long wavelengths. Classroom size is better for modes but they are typically too reflective (typical situation at audio shows). Open concept living rooms with high tilted ceiling and walls with wooden frames are best. I have three good stereo sets, but only one in a good room.
Recession just above 100Hz is typically because of the vertical mode, ears/mic are too close to mid of height...
Room's reflectiveness can be seen from REW measurements from listening spot, by RT60 and Clarity analyses. They give absolute values and graphic presentation, but one must have measuements from different rooms to interprete them. Wavelet spectrogram is what I look at first nowdays. Eq doesn't help, only acoustic treatment!
DSP, Audacity, Dirac etc. with forum discussions showing measurements have made room EQ too technical and people don't trust their ears anymore... And personal preferences are allowed too! We get accustomed to a room's acoustics quite soon, if it is not extreme. A smallish room (smallest dimension less than 4m) has very problematic modes and positioning alternatives are minimal regarding long wavelengths. Classroom size is better for modes but they are typically too reflective (typical situation at audio shows). Open concept living rooms with high tilted ceiling and walls with wooden frames are best. I have three good stereo sets, but only one in a good room.
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The first part I don't agree with as something that is always true. The second part I do, whatever gives the best results is the right way to do it
So far for me every room has ended up with a different measurement and EQ scheme.
So I did the MMM measurements of the left and right speakers..
Here is how it looks like:
I have many questions now.. Some of them being the following.
Is there a standard reference for room correction (book/webpage/document/thread)?
1) In the video, they say look at the measurements only up to 700 Hz or so for room correction. Do I need to apply some averaging (more than 1/24 per octave)?
2) The left and right speakers look like having huge dips at 50-60 Hz region.. what will that be caused by? (strangely, the AC power supply in my region is at 50-60 Hz frequency, so I had doubts about is it being caused by some hum due to that or actual room modes)
3) Are there standard room correction target responses (other than the Harman target curve)? This is so that I will have some reference to start with
4) Do I allow REW to do the correction as per a target curve or need to apply manually (at least in some frequency bands)? (what Q and max gains am I allowed to use while doing this correction) ?
Now I also need to go and check DRC-FIR
Thanks
Vineeth
Here is how it looks like:
I have many questions now.. Some of them being the following.
Is there a standard reference for room correction (book/webpage/document/thread)?
1) In the video, they say look at the measurements only up to 700 Hz or so for room correction. Do I need to apply some averaging (more than 1/24 per octave)?
2) The left and right speakers look like having huge dips at 50-60 Hz region.. what will that be caused by? (strangely, the AC power supply in my region is at 50-60 Hz frequency, so I had doubts about is it being caused by some hum due to that or actual room modes)
3) Are there standard room correction target responses (other than the Harman target curve)? This is so that I will have some reference to start with
4) Do I allow REW to do the correction as per a target curve or need to apply manually (at least in some frequency bands)? (what Q and max gains am I allowed to use while doing this correction) ?
Now I also need to go and check DRC-FIR
Thanks
Vineeth
Using which measurement can I get RT 60 and related parameters? Is it REW's regular sine sweep taken from listening position? Same question regarding wavelet spectrogram.
My room is 4.5m (Length) x 4.5m (breadth) x 2.8m (Height). This living room opens into the dining area on one side. Hence the room is not completely closed too.. So 1/3rd of the wall from one side is missing compared to a closed cuboidal box.
It looks like this from the side of that missing piece of the wall
(I can sort of feel from above pic that it is a room mode/refelction nightmare
) Is REW room mode simulatior of any use to identify modes etc in this overall Room EQ process?
Targets to look for when I search for the next accomodation..
But where I am living currently, it is very very costly to afford a rented accommodation bigger/having a nicer layout than this current one..
Hello Vineeth
You should try to play both with the tilting of the loudspeakers but also try with a chair to make closer your listening spot in order to compare the 3 ways VS the horn that has not the same output dispersion.
It is often reacher in learning than one think and not as easy to place the loudspeaker according the room.
You should try to play both with the tilting of the loudspeakers but also try with a chair to make closer your listening spot in order to compare the 3 ways VS the horn that has not the same output dispersion.
It is often reacher in learning than one think and not as easy to place the loudspeaker according the room.
Yes Vineeth, when I proposed the MMM idea I meant to say to compare the 2 different speakers. Not the L vs R of the same speaker.
The dips and peaks you see around 50-60Hz is due to your room. If you measure your woofers in the nearfield eg. 20mm I'm certain there's plenty of output around 50-60Hz.
The dips and peaks you see around 50-60Hz is due to your room. If you measure your woofers in the nearfield eg. 20mm I'm certain there's plenty of output around 50-60Hz.
I agree with this. I have always found an improvement when I increased the space behind my head. sitting with my back close to the wall has never been good for me.
Great progress Vineeth, I look forward to reading your posts every morning as I sip coffee... The temperature is -9 C this morning, so there is a lot of coffee...
Being near a wall reenforce the boomy signature. But this is not the only bad behavior indeed.
Being inside the listening triangle , i.e. closer from the loudspeakers than the length of their gap width gives good result but is not waf. I find cool Vineeth also stand his towers far from the rear walls as Most of loudspeakers image and snap better with such placement.
https://suesskindaudio.de/en/aufstellanleitung/
Being inside the listening triangle , i.e. closer from the loudspeakers than the length of their gap width gives good result but is not waf. I find cool Vineeth also stand his towers far from the rear walls as Most of loudspeakers image and snap better with such placement.
https://suesskindaudio.de/en/aufstellanleitung/
Hi,So I did the MMM measurements of the left and right speakers..
Here is how it looks like:
View attachment 1111232
I have many questions now.. Some of them being the following.
Is there a standard reference for room correction (book/webpage/document/thread)?
1) In the video, they say look at the measurements only up to 700 Hz or so for room correction. Do I need to apply some averaging (more than 1/24 per octave)?
2) The left and right speakers look like having huge dips at 50-60 Hz region.. what will that be caused by? (strangely, the AC power supply in my region is at 50-60 Hz frequency, so I had doubts about is it being caused by some hum due to that or actual room modes)
3) Are there standard room correction target responses (other than the Harman target curve)? This is so that I will have some reference to start with
4) Do I allow REW to do the correction as per a target curve or need to apply manually (at least in some frequency bands)? (what Q and max gains am I allowed to use while doing this correction) ?
Now I also need to go and check DRC-FIR
Thanks
Vineeth
1) i used REW "psychoacoustic smoothing" which supposedly mimics how hearing system smooths things out. I guess any smoothing would be fine to spot trends in the response. I'm not sure if any dramatic high Q tweaks are benefitical at this stage. You probably got those in the semi-anechoic measurements and are already "fixed" with crossover settings.
2) Since listening spot is near wall there should be no dip on that dimension (room depth), only boost. So I suspect the listening spot is middle of room width and its that, lowest mode of your room width makes a dip. If its true, it migh be gone if you measure both speakers playing simultaneously
Perhaps add and locate a subwoofer somewhere center of the room width. 3) There is harman target curve for loudspeakers as well, but as Juhazi and perhaps others said you should do it by ear. Figure out what you like in your room. Any target curve could be of with your particular setup, trust your ears and make it sound good
this is what speaker directivity is part of, roughly power response between Schroeder and tweeter beaming, or PIR in VCAD.You might find out one of your speakers sound better than the other on this regard and learn! https://www.audiosciencereview.com/...e-why-is-it-represented-as-a-thin-line.19886/
4) You can if you want to but I'd go by ear. Due to room modes especially the bass is tricky, weird looking measurement might sound better to ear than better looking one. Take your time and figure out, learn how graphs and sound relate together in you room and speakers. Perhaps try get close to some target curve and tweak from there. Have fun!
@diyiggy and @tktran303: Sure I will do an MMM measurement next time I hook up the horns instead of the current 2 ways..
@diyiggy: Thanks for that nice article. I am reading it and understanding. I will experiment with the same
For the horn system, I followed the following philosophy for speaker placement. It says that for the type of speaker considered, early reflections are useful and need not be damped much.
http://www.gedlee.com/Papers/Philosophy.pdf
It works exactly as he tells in the paper. the horns have sort of close to 90 degree coverage pattern. I placed the system such that the firing line on horn axis crosses in front of my head. The system was toed in at 45 degrees.
While listening, I would either sit on that sofa upright or pull a chair in front of it and sit there.. There was great imaging. I could locate instruments/sounds very well in space between the speakers. The soundstage was nice as well. I never felt it was a little too tight when compared to my first horn system with the LTH142 horns.
The current 3way system is toed in about 30+ degrees I think. The first thing I can notice pretty quickly is the slight lack of the kind of imaging that I had in the horn system. However, the horn system was a little "hot" in the upper midrange and treble (which I don't know is because of the titanium compression driver or something else). And I am identifying this only once I started hearing the current system.
@hifijim: Thanks a lot.. I eagerly look forward to your thread/posts too. Especially, that upcoming purifi build...
I wish I could do these kinds of speaker things/experiments for more time than I usually have time for.. Most often my job sucks the life out of me..
Here, the temperature dips to only around 11 degrees in the mornings.. So it is still comfortable these days. Come december/Jan, I don't know how it is all going to be, given the drastically changing climate these days. But usually, it has never dipped below 10 degrees or so here..
@tmuikku: Thanks a lot. I will follow these instructions carefully and try to implement it and see..
@diyiggy: Thanks for that nice article. I am reading it and understanding. I will experiment with the same
For the horn system, I followed the following philosophy for speaker placement. It says that for the type of speaker considered, early reflections are useful and need not be damped much.
http://www.gedlee.com/Papers/Philosophy.pdf
It works exactly as he tells in the paper. the horns have sort of close to 90 degree coverage pattern. I placed the system such that the firing line on horn axis crosses in front of my head. The system was toed in at 45 degrees.
While listening, I would either sit on that sofa upright or pull a chair in front of it and sit there.. There was great imaging. I could locate instruments/sounds very well in space between the speakers. The soundstage was nice as well. I never felt it was a little too tight when compared to my first horn system with the LTH142 horns.
The current 3way system is toed in about 30+ degrees I think. The first thing I can notice pretty quickly is the slight lack of the kind of imaging that I had in the horn system. However, the horn system was a little "hot" in the upper midrange and treble (which I don't know is because of the titanium compression driver or something else
). And I am identifying this only once I started hearing the current system.@hifijim: Thanks a lot..
I eagerly look forward to your thread/posts too. Especially, that upcoming purifi build... I wish I could do these kinds of speaker things/experiments for more time than I usually have time for.. Most often my job sucks the life out of me..
Here, the temperature dips to only around 11 degrees in the mornings.. So it is still comfortable these days. Come december/Jan, I don't know how it is all going to be, given the drastically changing climate these days. But usually, it has never dipped below 10 degrees or so here..
@tmuikku: Thanks a lot.
I will follow these instructions carefully and try to implement it and see..
So tilt down the treble a bit more, even 1 dB can make a huge subjective difference here. This is a common observation when using such waveguides - the total energy radiated is simply higher compared to say a common dome tweeter. The KVAR is still pretty constant directivity. Maybe too much but that would be a different topic (without a conclusion I'm afraid).
Sine sweep at listening spot is what I use for room analysis.
By the way my main listening chair is too close to back wall too, but it is a single so it's easy to grab a litte closer to speakers for critical listening
Good reading
http://seanolive.blogspot.com/2008/12/science-of-sound-recording-and.html tells about Harman speaker tests etc.
https://www.audioholics.com/room-acoustics includes articles by Floyd Toole
https://www.linkwitzlab.com/The_Magic/The_Magic.htm
http://www.cardas.com/room_setup_rectangular_room.php
More scientific reading https://research.aalto.fi/en/organi...ial-sound-and-psychoacoustics-2/publications/
By the way my main listening chair is too close to back wall too, but it is a single so it's easy to grab a litte closer to speakers for critical listening
Good reading
http://seanolive.blogspot.com/2008/12/science-of-sound-recording-and.html tells about Harman speaker tests etc.
https://www.audioholics.com/room-acoustics includes articles by Floyd Toole
https://www.linkwitzlab.com/The_Magic/The_Magic.htm
http://www.cardas.com/room_setup_rectangular_room.php
More scientific reading https://research.aalto.fi/en/organi...ial-sound-and-psychoacoustics-2/publications/
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I'm not very familiar with it, I've only used REW few hours and all within past month or so@tmuikku: Thanks a lot.
trying to do the same as my advice, listen and figure out what I'm measuring and how graphs and sound relate and how to develop the loudspeaker system further The system needs to work with the room, we are listening sound in a room.
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If you want a book I would start here
https://www.amazon.com/Accurate-Sound-Reproduction-Using-DSP/dp/1520977905
Room Correction is a terrible term as you can't correct a room with EQ. You can reduce modal resonance peaks and generally correct the tonality. You can correct for timing errors (but not with a MMM) and try and rebalance some areas that might be messy and can't be fixed at the source for whatever reason.
One of the main advantages is making the left and right speakers become closer to the same in frequency response and level. This in of itself has a big impact on imaging and spatial impression.
A MMM is already a spatial average, there is no real reason to apply smoothing but it won't hurt if you do. Confining corrections to specific frequency regions without understanding why is silly. There are good and legitimate reasons to treat different frequency ranges separately. I have not seen a speaker yet that couldn't be improved even if just a little bit by a full range correction. The problem is that doing it right is not always easy and there is no super simple recipe to follow to get great results. You can absolutely make things worse by doing it badly. Hearing doesn't work like a microphone does so there is not a direct relationship between a good looking measurement and a good sounding result. It is absolutely possible to make something look good but sound bad particularly if you introduce phase correction.
It's not your power line but where you have placed the speakers in relation to the boundaries. This is called SBIR. You can try and use the REW room simulator or a basic calculator such as this one http://tripp.com.au/sbir.htm
You have some very deep dips at about 55Hz in both channels give or a take a few Hz, there are also two separate nulls making it up, this is why the null is skewed to the side. I would guess that you have them 1500mm or so from some boundary or more likely a couple of boundaries that are similar in distance,
I would start with 1dB/octave fall from 20 to 20K, I personally don't like the bass to keep rising all the way down, I prefer it to level off a bit from 100Hz down, but as with all of this you have to find your own preference. You can then go steeper or shallower with the slope and hear the difference. REW can introduce this as a target quite simply.
Low frequency EQ is usually better done by hand, REW's auto EQ can be quite helpful but the target settings make a big difference on what it will do, fiddling around with those can generally help to get REW to do the heavy lifting. There is no maximum gain and Q to use or not use and I wouldn't recommend to think like that, sometimes you need to use a combination of filters to get the response you need. REW might use three high q filters to make a wider low Q filter with a specific shape. Having said that if you end up wanting to use high Q's and high boost then you need to consider why and if it will actually make an audible difference. Try it out for yourself to get a feel for what matters.
Learning to read the measurements for yourself is key in understanding what to touch and what to leave alone. The information is not contained within one single graph or measurement, they all have value in making a decision on what to do. The windowing or averaging applied makes a big difference to help get a look at what to change.
Just a quick note: If you do boost a frequency, have the microphone ready to see the result. If a dip is created by something like a wall reflection, you can boost all you want, but that reflection will still be there to subtract the energy. So concentrate on cuts to match the in-room curve you want to create, and if you do end up boosting, see if the frequency response actually improves. Also watch the distortion at those spots.
If you would change the position of the speakers, to be a little less symmetrical, you may be able to avoid having the dips in both channels line up like that.
If youre free to move them wherever you want, you could try setting them up in the corner. A bit like this: https://www.hometheatershack.com/threads/corner-setup-problem.15868/#lg=thread-15868&slide=1. Measure it like that and compare...
If you would change the position of the speakers, to be a little less symmetrical, you may be able to avoid having the dips in both channels line up like that.
If youre free to move them wherever you want, you could try setting them up in the corner. A bit like this: https://www.hometheatershack.com/threads/corner-setup-problem.15868/#lg=thread-15868&slide=1. Measure it like that and compare...