It is very important to understand that room affects the sound heavilly up to the Schroeder frequency and moderately up to 500-600Hz. This has been proven with numerous researches and can be eadilly verified by measuring your own room.
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- Thread starter Willem
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It is very important to understand that room affects the sound heavilly up to the Schroeder frequency and moderately up to 500-600Hz. This has been proven with numerous researches and can be eadilly verified by measuring your own room.
But the result correction over 80 Hz will be wrong Im affraid. In a normal listening room- youre listening to mostly reflected sound from the listening chair. The correction made around schroeder are only correct at one single place. At all other places the sound correction gonna sound worse than without.
When you try to correct frequencies thats not resonances happening between two walls, the result at the listening place is going to be wrong.
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Real improvements can only be made when youre correcting resonances in a room that happens between two surfaces- In a normal room those frequencies are all gonna be beneath 80 Hz, the first at around 72 -74 Hz if the distance between the floor and ceiling is about 2, 40 meter.
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Can you lay out your training and expertise in this area? Always leery of new people telling us all how wrong we are.
If correction is based on spatial measurements that "single place" is big enough.
In my case this is not true - FR was flatter thrughout the entire room but it is optimally flat at the LP. I don't think you can generalise like that.
Btw, can you post links to some research papers supporting your claims?
- Thread Starter
- #66
The Schroeder frequency depends on the size of the room. Below it equalization is possible, and corrects room modes (i.e. resonances at the room's major dimensions). Above that, equalization does not really work because the peaks originate in reflections rather than resonances. The Schroeder frequency of my listeng room is about 120 Hz, but smaller rooms can have Schroeder frequencies up to about 250 Hz. You are right that equalization is best in one listening position, but that single listening position is only very small at higher frequencies because the wavelength of the sound is so short. At low frequencies the correction works over a wider area, and all the more so if the measurement is spatially averaged. Using two (or more) subwoofers with equalization is an even better solution as it reduces the magnitude of both peaks and dips, and creates a smooth response over a much wider area.
Can you post some measurements to prove that? How big is your room?
- Thread Starter
- #68
It is really big (some 13m length). I used an online calculator with the room's dimensions as input. In reality it is even bigger than what I used for the calculation, because it is an open plan. My REW measurements also suggest that roughly below this frequency response becomes more jagged.
And above 120Hz response is not affected with the mic position? I would like to see measurements proving that.
What is the width of your room?
- Thread Starter
- #70
The room is mostly about 4,5m wide, but sometimes double that, and 3.1m high. I don't quite understand the question about the response above 120 Hz. It is pretty smooth with quite low decay times when the curtains are half closed. The decor is modern and quite minimalist with huge windows but with large bookcases and curtains. A hard floor, but a large Persian rug. We are looking for a new sofa and we are planning on one that is a bit more absorbent, and to add a big pouf with cloth upholstering more or less in front of the speakers, because a bit more damping would be nice but I do not want to have technical room treatment stuff to mess up an elegant modern interior.
Your room is not a typical room in any way. I would like to see multiple measurements taken from various position in your room supporting your claim that it has transition frequency below 120Hz. You are talking about room EQ yet you haven't posted a single measurement.
You should also understand that Schroeder frequency is not a brickwall limit so resonances are possible, but to a less extent, above it as well, up to 500-600Hz region.
Additionally, while resonances are manifested as peaks and while they present more harm to SQ, there is no law against correcting the dips as well, as long as you don't overdo it - personally I don't correct more than +12dB for dips in the region below Schroeder frequency.
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- Thread Starter
- #72
No it is not typical because it is large and also has a somewhat atypical shape. Mind you, and I want to remain friendly, but the estimated Schroeder frequency was calculated from this site: http://www.acoustic.ua/forms/room-modes-eng.html It could be a bit different, but I am not imagining anything. The REW graph seems to confirm this. Beyond that, why are you interested in my room rather than the general principle on which we seem to agree? My room is not interesting for anyone other than me. The relevant point is that equalization only works well below the Schroeder frequency, and as I said, it works fairly well and, as you said about your room, over a larger area than was suggested. Even so, below about 100 Hz it is not as smooth as I would like, even though I am using the Antimode 8033.
I am now busy, but I will try to post a waterfall image.
I am now busy, but I will try to post a waterfall image.
Those calculators are for estimation pruposes only - the only valid way to conclude about the Schroeder frequency is to make multiple measurements in your room. But one more time - Schroeder frequency is not a brickwall filter - room will affect the frequencies beyond it as well, but from that point room influence will progressively fade away.
Waterfall image is irrelevant to this discussion.
So, asking you to present your measurements that prove your point was strident? Heh..
Correct.
Resonances = between two solid walls in the room, or the floor/ceiling. In a real room there is no room-resonances higher than 80 Hz, unless you live in a very, very small room.
soundspeed is 34,3 cm in 1 ms. That is the wavelength of 1 kHz. You can now easily calculate the room resonances measuring the distance between the solid walls. No microphone is needed at all. There are only three major resonances in a normal rectangular room. Between front/back wall, floor/ceiling, and between right and left wall.
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Sure. I wonder why room EQ software make adjustments based on multiple mic measurements instead on calculations based on room model.
Divining rods work for me.
I have done extensive studies of Toole, and I have been learning a lot from Peter Stendl, Ingvar Oman from Sweden. And have done a lot of measurements and some constructions.
https://www.faktiskt.io/phpBB3/viewtopic.php?f=3&t=69180
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