musical noise said:
I think that it is perfectly reasonable to get "good" sound WITHOUT measurements, etc. Marcus asked how I do it and I told him. He thinks that this is too complex for the "average" person and I agree, it is. But I was assuming that Markus is above average and perfectly capable of doing this right.
In order of my preference, here is what I would do:
1) great mains, three subs, in-situ room setup with measurements
2) great mains, three subs setup by ear
3) great mains, two subs setup with measurements or by ear
4) great mains, one sub setup by ear (measurements won't do much here)
5) great mains
There is a common thread in all of this that I think is obvious - buy great mains that are designed and tuned to be optimal. Don't even attempt to try to build these without measurements and a great deal of experince.
Then get "several" subs and set them up however you can, with or without measurements. But with measurements you will be able to obtain the last little bit of LF performance that your room will allow. This last step CAN ONLY be done in-situ and as such it has to be done by the end user or by a professional 'house-call'. (I would beware of the "professional house call" - I have talked with some of these guys and quite honestly you'd be better off setting up the subs by ear.)
The equipment choice is simple - a Beringer mic and preamp (maybe $100 for both), sound card, or even use the sound card in your laptop (been there done that), software that will do FFT averaging. It doesn't even have to be real time - Cool Edit would do this. There are scores of program that will do this (at least on a PC, Macs seem to be much more limited.). CABLES and thats it. The rest is learning curve.
soongsc said:
I'm sorry, but in my thesis I did not just deal with "fully developed modes" - whatever those are. I also studied damping and modal decay. You jump to many conclusions that are simply not correct.
Your last point makes no sense.
You're not so sure anymore? Or how am I supposed to understand "In my opinion Markus is done, has been for days." and "You really need to read up on frequncy response measurements in small rooms."?
gedlee said:
Thanks Earl for this very valuable post. Following along on the sidelines, I was beginning to get a sense of frustration on Markus' part with the measurement side of the set up. Consequently, I was contemplating a post strongly recommending he put away the test mic and computer and simply spend some time listening to music and positioning his speakers until he found what he thought was the best he could do by ear (once he straightens out his electronics). Then, perhaps, do another measurement and share that.
It's become obvious to me that although waveguide technology may have it's advantages, buying and building a DIY kit of same is certainly not for the beginner. And, as far as all the subs are concerned, eeking out "that last little bit of LF...."? Seems like a lot of work and cost for marginal improvement. IMO, the waveguide kit is were the real gold is.
If you actually dealt with multiple modes at the same time, I'd sure like to see that thesis. However, as almost all theses, I won't be surprised that it deals with a nich portion of reality. But I'm sure it must have been of significance of it's time.gedlee said:
A mode will not develope until sound wave has at least reflected once. If there is some obstruction, it will cause reflection in other directions, and thus the mode in the original direction will not be as strong as it would without the obstruction.
markus76 said:
Marcus
What you posted several days ago looked fine to me.
Then you went on looking at details that I thought were insignificant. I wouldn't have bothered. Clearly you have not studied the statistical nature of the sound field in a room and that is simply NOT something that I am going to get into on line. It is well documented elsewhere in a whole array of works, many under my name. But the fundamental paper is by Manfred Schroeder - it was done in the 50's while he was still in Germany. I translated this paper into English for my thesis as it was not widely know. The AES wanted to publish my translation and sent it to Schroeder for review. Schroeder then agreed to do the English translation himself and it was published in the AES back in the 80's. This is simply a minimum understanding that one must have to get into the kinds of room measurement discussions that you seem to want to have.
But I would simply say to you that you are done. Turn off the measurement stuff and just listen.
If you want to get into the deep details of this issue then read the Schroeder paper and then my AES papers from about the same time called "The Equalized Sound Power Method" and another one whose name eludes me right now. Then contact me off-line as this topic is far too analytic for general discussions.
speakerdoctor said:
I am not sure that I understand you correctly, but please don't get me wrong.
Multiple subs is NOT a "marginal improvement" its a MAJOR improvement, in fact IMO its a requirement. What might be considered "marginal" is the setup using measurements. It might be marginal in the sense of extra cost and time, although its performance benifits are most certainly notable. "Marginal" is subjective.
New day, new data - the extended LF response sounds like "louder" bass although the overall level hasn't changed:
Skywave-Rider, (German) beer preferred (lots of it)
An externally hosted image should be here but it was not working when we last tested it.
Skywave-Rider, (German) beer preferred (lots of it)
Markus
Looks good. A little unclear on the response to DC, but that can be dozens of things.
I prefer Guiness, Thanks.
Looks good. A little unclear on the response to DC, but that can be dozens of things.
I prefer Guiness, Thanks.
speakerdoctor said:
I would say this - assembly with Johns new precut boards would be very easy, crossover setup is likewise trivial, mounting the drivers etc, is also easy, especially now that I have refined the CD mounting technique (it comes pre-fitted and drilled).
BUT, finishing is not easy. Unless you are experinced at filling and sanding and painting, these things are easy to talk about and actually do, but they do take some skill and knowledge.
I have a very elaborate paint setup now and can do great high gloss piano type finishes in many colors. When I build the speakers they are tested. Thats all the hard work.
In restrospect, I should have added 'setting up' to the list of 'buying and building'.......
Don't understand Markus' lastest test curve. Is that response below 20 hz real or an artifact of some sort?
Don't understand Markus' lastest test curve. Is that response below 20 hz real or an artifact of some sort?
Lots of other things can cause the VLF data to rise. Since I do my own processing, I always look at the DC or averega value of the data - it has to be zero. If there is DC data, then I just take it out. Almost always the signal at these VLF goes down. But there can still be other things. Remember, I use two channel techniques so my data is noise imune, but NOT calculation error imune.
markus76 said:
None of this data would pass muster in intro physics 101, EE300 series, etc. You don't give any analysis of error, state the conditions, show std.dev. with repeats, etc.
As Dr. Geddes said, statistics matters, but if your results make you feel better that your speakers sound good, I guess it doesn't matter. Just don't take any rigorous college lab courses... 😀 😉
John L.
? I think you missed a couple of my last posts. My data comes with more comments on how I captured it than I can find in most posts of others. And there's no secret at all. What do you want to know?
auplater said:
I don't get the impression that Markus is trying to prove anything. Seems like he's just trying to do a proper job of set up, and understand what he sees. No need for such rigor in that case. As long as the measurement limitations are understood, one can make progress.
Sheldon
auplater said:
The statistics that I am talking about are not "errors" any more than rolling a die three times turns up three heads - its NOT an error. Its the statistics of sampling a sound field. So please don't tie me to such an impolite posturing.
With the original position (page 1), these things concern me:
1. the front wall and any reflective obstruction between the speakers (i.e. the TV).
2. the wall/boundary loss as both a point of reflection and as a pressurized boundary to the left of the left speaker. (the hall-way and kitchen area.)
3. the corner/short side-wall near the listener's position.
#1 serves as a point of reflection and reduces the perception of depth. This has more to do with lower mid-band freq.s than higher freq.s.. A wavelength at 400 Hz is almost 3 feet in length - a distance that you are probably within from acoustic center to wall reflection in your current configuration. I'd personally like to see DOUBLE that distance FOR JUST THAT FREQ. (for critical listening), and I'd really like something closer to 15 feet total - which would move you beyond the correlation threshold for most localizable freq.s.. This recommendation is not entirely in keeping with Earl's - he prefers absorption. However, its tough to get enough absorption at these lower freq.s in a particular "spot".
#2 here you haven't maintained a uniformity of the sound pattern to your listening position. Maintaining uniformity is often more important than lowering a reflection's time and level. Depending on the size of acoustic center and the loudspeaker(s) themselves (physical size), you can actually get good sound in a small bathroom. It will likely be unbelievably reverberant, but the brain can adapt to this fairly quickly. What the brain has a difficult time with is trying to reconcile 2 channel playback with non-symmetrical lateral reflections.
#3 IMO this is your worst problem. That corner and side-wall is effectively creating a near-field cross-channel loudspeaker. Your *right* loudspeaker is firing directly into it and you are sitting right next to it. I have no idea what the result would be, but I don't think that it could possibly be good.
My suggestion:
Place your sofa near (but not directly up against) your "window"? wall. Facing toward your kitchen as in your photo. Centered seating between the two side-walls (i.e. both long walls). Your ears just ahead of the support column to your left (i.e. toward the kitchen rather than the window).
"ottoman"? in front of you at your listening position. Loudspeakers about 7-9 feet away from you along the side-walls (long walls). From the loudspeaker's closest corner to the wall should be at least a foot. Loudspeakers "aimed" "in-ward" per specification. This should give you a basic visual (though with more "toe-in" for you):
http://www.arduman.com/aa/Sayfalar/adnans/adnans3/syst.htm
..an interesting comment on one particular aspect of the sound of this system:
"For me the most striking point was the exceptional depth of the sound stage. Especially while listening to a big orchestra, hearing some of the instruments five meters behind the speakers makes it very life like indeed."
..as for your TV - place it on a rolling stand and move it into position when you want to critically view something. For more casual viewing consider your "corner" to the left (aimed diagonally into the room).
place other furniture as required - and it can even be almost directly behind the loudspeakers.
..anyway, its a suggestion.😉
1. the front wall and any reflective obstruction between the speakers (i.e. the TV).
2. the wall/boundary loss as both a point of reflection and as a pressurized boundary to the left of the left speaker. (the hall-way and kitchen area.)
3. the corner/short side-wall near the listener's position.
#1 serves as a point of reflection and reduces the perception of depth. This has more to do with lower mid-band freq.s than higher freq.s.. A wavelength at 400 Hz is almost 3 feet in length - a distance that you are probably within from acoustic center to wall reflection in your current configuration. I'd personally like to see DOUBLE that distance FOR JUST THAT FREQ. (for critical listening), and I'd really like something closer to 15 feet total - which would move you beyond the correlation threshold for most localizable freq.s.. This recommendation is not entirely in keeping with Earl's - he prefers absorption. However, its tough to get enough absorption at these lower freq.s in a particular "spot".
#2 here you haven't maintained a uniformity of the sound pattern to your listening position. Maintaining uniformity is often more important than lowering a reflection's time and level. Depending on the size of acoustic center and the loudspeaker(s) themselves (physical size), you can actually get good sound in a small bathroom. It will likely be unbelievably reverberant, but the brain can adapt to this fairly quickly. What the brain has a difficult time with is trying to reconcile 2 channel playback with non-symmetrical lateral reflections.
#3 IMO this is your worst problem. That corner and side-wall is effectively creating a near-field cross-channel loudspeaker. Your *right* loudspeaker is firing directly into it and you are sitting right next to it. I have no idea what the result would be, but I don't think that it could possibly be good.
My suggestion:
Place your sofa near (but not directly up against) your "window"? wall. Facing toward your kitchen as in your photo. Centered seating between the two side-walls (i.e. both long walls). Your ears just ahead of the support column to your left (i.e. toward the kitchen rather than the window).
"ottoman"? in front of you at your listening position. Loudspeakers about 7-9 feet away from you along the side-walls (long walls). From the loudspeaker's closest corner to the wall should be at least a foot. Loudspeakers "aimed" "in-ward" per specification. This should give you a basic visual (though with more "toe-in" for you):
http://www.arduman.com/aa/Sayfalar/adnans/adnans3/syst.htm
..an interesting comment on one particular aspect of the sound of this system:
"For me the most striking point was the exceptional depth of the sound stage. Especially while listening to a big orchestra, hearing some of the instruments five meters behind the speakers makes it very life like indeed."
..as for your TV - place it on a rolling stand and move it into position when you want to critically view something. For more casual viewing consider your "corner" to the left (aimed diagonally into the room).
place other furniture as required - and it can even be almost directly behind the loudspeakers.
..anyway, its a suggestion.😉
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