How many days do you spend on calibrating your subs? Maybe we all should wait until Weltis SFM makes it into a product sold by Harman...
Here are 3 positions - middle and 15 cm to the left and to the right:
Here are 3 positions - middle and 15 cm to the left and to the right:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
A more organized approach is to do room modes analysis. A program like SoundEasy allows one to measure your speakers, and run a frequency response analysis for your selected speaker location and listening position. This will probably help narrow down on setup options.
soongsc said:
I've set up my main monitors in my apt. using the Harman room mode calculator. It's probably crude compared to what soongsc suggests.
It shows all the "hazardous" locations for nulls and peaks, which gives you an opportunity to place the monitors initially in the least offensive spot.
Get the best placement you can, then work on treatments/subs/eq.
I intend to get Soundeasy, but as a Mac guy such as yourself, I am waiting for a new laptop which can Bootcamp Windows.
Having said that, maybe you've done this already.
markus76 said:
I can usually do it, using the technique that I described before, in an hour or two at the most, with a second person helping with the spatial averaging. Its really quite simple, but you have to be looking at good data.
The general belief in the industry is that 6 mic positions spatially averaged and then 1/3 octave frequency average will be good to about +- 2 dB. You can see that the fine detail from curve to curve does not match. When this is averaged out you will see the "real" response. If you run the FTT for ten (or more might be better) averages and during this time you have moved the mic around by several feet you will get a good approximation with 1/3 or 1/6 octave averaging. But doing it at fixed microphone locations is a real PITA. Just sweep the microphone - this is the way that all power response tests are done in reverb chambers.
What is "Welti's SFM"? Being JBL, it won;t be cheap no matter what it is.
I believe that "room mode calculators" are a waste of time. The real room is never modelable and the exact locations of the modes is irrelavent when you use multiple subs. The room is what it is and multiple subs will always get the best out of it no matter what it is.
Is there a problem with my last 3 diagrams? Does it get any better?
"Sound field management" as described in "Low Frequency Optimization Using Multiple Subwoofers" by Welti/Devantier (JAES 54 #5 2006).
Don't know how much such a thing would cost, but your method also isn't cheap in terms of learning curve, time and equipment needed.
gedlee said:
So does Markus have the required gear to do this?
If yes, what's taking so long?
If not, what is recommended? (I am aware you use custom designed software.)
This would benefit all of us in setting up loudspeakers.
Markus
Learning curve perhaps, but the equipment is minimal and so is the time if you do what I suggested. You showed a great response several days ago and that only seemed to take you a few hours. Seems to me your just looking at minutia that may or may not be real.
As I've said over and over. Spatially average and frequency average to get something that is stable. Otherwise there isn't much that you can do. Your three data sets are different.
Learning curve perhaps, but the equipment is minimal and so is the time if you do what I suggested. You showed a great response several days ago and that only seemed to take you a few hours. Seems to me your just looking at minutia that may or may not be real.
As I've said over and over. Spatially average and frequency average to get something that is stable. Otherwise there isn't much that you can do. Your three data sets are different.
Skywave-Rider said:
So does Markus have the required gear to do this?
If yes, what's taking so long?
If not, what is recommended? (I am aware you use custom designed software.)
This would benefit all of us in setting up loudspeakers.
Wow - I went through this several times already, its in the past posts. All you need to do is sweep the microphone - how hard is that!? (We are talking about below 200 Hz here - you can't do that above 200 Hz.) And all you need is simple analysis software that can do averaging of data sets - free in many cases. For setting up the subs I DON'T use custom software - thats a different thing altogether. I use Spectra-lab in this case, but thats because I like it for other things.
In my opinion Markus is done, has been for days. Looking at narrow band spectral of in room responses is never very usefull. There is too much fine structure to the data, and most of it not real in terms of audio and perception. The noise file has limited time and even it may have uncertanties in its spectral content. I think Marcus wants to do a very high resolution measurement and this IS beyond the scope of what we are talking about here as well as his equipment.
Any automated system, like Markus wants, is going to have to be done on a very very "smoothed" set of data or it won't converge. Just because its a "black box" does not mean that its doing a good job.
gedlee said:
Wow. Onward!
Markus, do you prefer beer, wine or sake? I'm coming over....
Thanks for the info, Gedlee, I'll attempt to employ ur suggestions when I get Soundeasy.
gedlee said:
Yes, I thought those measurements shown in post 311 looked pretty darn good. I have no where near Earl's experience, but I've done quite a few measurements over the past couple of years with my DEQX. I can get very smooth corrected near field measurements - so the software/hardware combination is capable of it. But measurements taken at the listening position look like what you have shown. If I move the mike around, the small features change, but broad peaks don't. My guess is that these deviations are room characteristics (some perhaps due to the wall behind you), and maybe some smaller cabinet refraction effects. Likewise, to the extent that they are perceptible, I would guess that they are mostly perceived as room characteristics.
Sheldon
If I get some free time, I will go through the process in my room and post the results, but I am pretty backed up at the moment.
They are not if you take into account that the resolution is 1 Hz and the positions are 30 cm apart! That's normal deviations because of the positional changes. But the overall response is very good and the trends are all the same in all 3 data sets. What would have changed when moving the mic over the 3 positions while measuring?
Perhaps? For sure! Equipment one needs: PC, software, mic, preamp, cables to be exact. That's "minimal" for whom? For someone that just wants to listen to music or for someone that does consulting and speaker building for a living?
Could you provide information that enforces your point of view? And how many Subs create what effects?gedlee said:
Bare room modes are the worst conditions. For normal living conditions, the modes would not be as strong. When all axial and tangential modes are considered, quite often the modes will not be as strong. The earlier software used room image methods, and were not as effective as the FEM methods now used.
Unless your subs are implemented with very steep low pass cutoff, the more subs in the room just makes the bass more messed up. Although this does create a sensational experience, the user would need to be aware what they might lose.
Soongsc
You've got this all wrong. Modes are not "stong" or weak, they are modes. They beome strong or weak depending on source and listener positions within them. But room furniture makes the situation untractable because the modes for an empty room are not much like those for a filled room, and rooms coupled to other rooms through doors etc. are completely different still.
I did FEA room simulations for my thesis back in 1980, so I know a little about the problem.
"the more subs in the room just makes the bass more messed up"
This couldn't be further from the truth.
You've got this all wrong. Modes are not "stong" or weak, they are modes. They beome strong or weak depending on source and listener positions within them. But room furniture makes the situation untractable because the modes for an empty room are not much like those for a filled room, and rooms coupled to other rooms through doors etc. are completely different still.
I did FEA room simulations for my thesis back in 1980, so I know a little about the problem.
"the more subs in the room just makes the bass more messed up"
This couldn't be further from the truth.
Markus
There is simply no way that someone with no knowledge and no equipment at all can properly setup a sound system in an arbitrary room. It just won't happen. Sure they can go to Best Buy and buy Bose cubes and place them in the room - no problem. Sound good? No way. Will they love it anyways? Of course. We are talking about something and someone completely different here, not Joe Consumer. I have nothing to offer in that market.
There is simply no way that someone with no knowledge and no equipment at all can properly setup a sound system in an arbitrary room. It just won't happen. Sure they can go to Best Buy and buy Bose cubes and place them in the room - no problem. Sound good? No way. Will they love it anyways? Of course. We are talking about something and someone completely different here, not Joe Consumer. I have nothing to offer in that market.
When I mixed bands live, of course we used eq and pro gear, but at home, using a pre with no tone controls, no eq, I, well, the gear designers, actually, can also achieve excellent sound, at least with the speakers I have now.
Sound good? Way!
Sound good? Way!
gedlee said:
Dr. Geddes
Ok I'll agree that proper setup is essential for best sound in any room and have known this deep down for a long time know. I can certainly affect bigger sound differences from small speaker movements in the room than from any component change within the system.
So... could you find a little time (since you brought us here in the first place) to explain what a minimum measurement setup would entail as far as software equipment etc. and how one could go about measuring? Even if you could point to some resource it would be appreciated🙂
Well, if one only looks at room modes at the academic level, the modes are just modes because these analyses only deal with fully developed modes each individually.😀 From an engineering point of view, the process of mode development and decay is considered.gedlee said:
Where or not bass is messed up or not is dependent on how critical one is of accuracy.
loopguru said:
And you use Bose cubes? Or didn't you notce that part. To the consumre Bose cubes "sound good" - thats the point.
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