We had music parties when we were at college. Speakers were bass reflex cabinets with dual cone speakers.
We always played it in the open ( a terrace) at night and it used to sound great. Did have less low end than inside the room but vastly better sound.
Later when I moved home with a large living room, it was still better out in the open. All this must be of course be due to reduced reflections.
We want a "leaky" room at low frequencies, since it is the only practical way to suppress room modes (to heck with the neighborsBut why wouldn't it be the same for our rooms? Sound energy is precious!
). Above the modal frequencies diffuse reflected sound enhances "spaciousness" and "envelopment", but it must be done in such a way that it does not inhibit "localization" and "image" . . . which generally means some minimum room size is necessary to provide sufficient delay. In very small rooms broadband absorption (if you can find the space for it) is the only answer.
I agree, but it may not need to be too broadband, as Lolo mentions. I'll have to reread the research. I'd love to do the actual experiment.
At IRCAM we had all sorts of movable walls and baffles, but I never got to play with them.Possible, but I don't think so. There was nothing of any consequence out there, except the concrete driveway itself. The trees were quite far, and I didn't notice and slap back from them. It could have been a reflection off the driveway, but the angle didn't seem right for where the sound was virtually placed. I suppose that some dirt and sod placed over the driveway would have been interesting to try.
Hi All
Hi Earl
I have a link to the STIpa test signal which is the set of modulated bands.
If I recall, this would have a spectrum like a voice (not flat weighted). I remember too now that they said intelligibility goes down if/when the average level exceeds the 80-90 range fwiw.
If you have ARTA, that has a MTF measurement but little explanation about how to read it. RA7 posted some measured results which do show significant differences as the modulation frequency is increased.
Downloads | Studio Six Digital
Hi Pano
Sorry I had to dash, my daughter got stuck in the driveway (we got 9 inches of snow, she was driving a 4wd dodge, go figure, go off the drive into the grass, you get stuck).
In the 80’s and 90’s I used to haul out all the stuff and set up the stereo in the back yard and usually have a bbq at the same time. In the way old days (when I had more ambitious friends) we would occasionally haul out a couch, furniture and table lamps and spend the night listening.
Anyway, it was the process of hearing many different speakers both inside and out that convinced me the room is not a help so far as preserving the stereo image that could be produced without the room. In a number of threads where people have argued for the presence of reflected sound somehow “improving the image” to set the same exact system up outdoors and hear it without room effects, THEN decide which is better, more real, instead of single ended assertions.
Certainly the entire chain of the recording and electronics, the loudspeaker, it’s directivity and interaction with the room govern how well or if a speaker can fool you (with the right recording) BUT if you listen outdoors, you have at least removed the room part as a comparison. Your garage door experience is very much along that line.
Also, the “front to back” ratio of the speaker (at whatever frequency) governs how much effect the rear walls have.
When the speaker projects a forward pattern say +20dB louder than to the rear, you are getting 99% of the energy going forward.
For the same reason, the greater the difference between the energy inside vs outside the intended pattern, the more the systems power response matches the on axis response.
For example, when you heard the SH-50’s, there would have been VERY little sound reflected from the rear wall little from side walls, all of which would have adversely affected the phantom image floating in the middle. That image was not intentional there but just the natural result of a mono signal BUT if one can make a strong mono phantom, one can produce a strong stereo image.
Hi Markus
Sorry, I don’t keep on top of where the speakers go other than casually so I am not sure about Switzerland. I do know they have signed some kind of distribution agreement with a company “over there” called Ampco/flashlight or something. On the other hand, the company focus is still on large scale sound and not the home.
Best,
Tom
Hi Earl
I have a link to the STIpa test signal which is the set of modulated bands.
If I recall, this would have a spectrum like a voice (not flat weighted). I remember too now that they said intelligibility goes down if/when the average level exceeds the 80-90 range fwiw.
If you have ARTA, that has a MTF measurement but little explanation about how to read it. RA7 posted some measured results which do show significant differences as the modulation frequency is increased.
Downloads | Studio Six Digital
Hi Pano
Sorry I had to dash, my daughter got stuck in the driveway (we got 9 inches of snow, she was driving a 4wd dodge, go figure, go off the drive into the grass, you get stuck).
In the 80’s and 90’s I used to haul out all the stuff and set up the stereo in the back yard and usually have a bbq at the same time. In the way old days (when I had more ambitious friends) we would occasionally haul out a couch, furniture and table lamps and spend the night listening.
Anyway, it was the process of hearing many different speakers both inside and out that convinced me the room is not a help so far as preserving the stereo image that could be produced without the room. In a number of threads where people have argued for the presence of reflected sound somehow “improving the image” to set the same exact system up outdoors and hear it without room effects, THEN decide which is better, more real, instead of single ended assertions.
Certainly the entire chain of the recording and electronics, the loudspeaker, it’s directivity and interaction with the room govern how well or if a speaker can fool you (with the right recording) BUT if you listen outdoors, you have at least removed the room part as a comparison. Your garage door experience is very much along that line.
Also, the “front to back” ratio of the speaker (at whatever frequency) governs how much effect the rear walls have.
When the speaker projects a forward pattern say +20dB louder than to the rear, you are getting 99% of the energy going forward.
For the same reason, the greater the difference between the energy inside vs outside the intended pattern, the more the systems power response matches the on axis response.
For example, when you heard the SH-50’s, there would have been VERY little sound reflected from the rear wall little from side walls, all of which would have adversely affected the phantom image floating in the middle. That image was not intentional there but just the natural result of a mono signal BUT if one can make a strong mono phantom, one can produce a strong stereo image.
Hi Markus
Sorry, I don’t keep on top of where the speakers go other than casually so I am not sure about Switzerland. I do know they have signed some kind of distribution agreement with a company “over there” called Ampco/flashlight or something. On the other hand, the company focus is still on large scale sound and not the home.
Best,
Tom
Wow! IRCAM! You are probably talking of their variable acoustic room. THE dream!
Ah, lolo, you know that room? Oui, la reve.
Hope the snow doesn't get you down too much.
Yep, maybe the strongest phantom center image I've ever heard in that kind of setup. (Meeting room, single mic). Very impressive!
Hope the snow doesn't get you down too much.
I have found that there is no amount of damping behind the speakers that is too much. I don't think that it should be anywhere else but behind the speakers. My damping is about 3 ft. thick foam. Its hard to get enough. Try adding damping until you no longer get an improvement. You will find that this probably does not happen before you run out of space.
Ah, lolo, you know that room? Oui, la reve.
Yep, maybe the strongest phantom center image I've ever heard in that kind of setup. (Meeting room, single mic). Very impressive!
Hope the snow doesn't get you down too much.
Re: phantom image. One way to ensure a rock solid center phantom image is to have the frequency response the same for both L and R speakers at the listening position through the audible range: http://www.diyaudio.com/forums/mult...ns-beaten-behringer-what-104.html#post3391543 I don't know any other way to improve on this...
Earl,
I take it that you are talking about the foam behind the speaker more in regards to a direct radiator than for a horn loaded system? I understand that most of us wouldn't have a large bass horn in our houses and that would get us back to a direct radiator of some sort, so you are saying that you need three feet of foam to attenuate low frequencies?
I take it that you are talking about the foam behind the speaker more in regards to a direct radiator than for a horn loaded system? I understand that most of us wouldn't have a large bass horn in our houses and that would get us back to a direct radiator of some sort, so you are saying that you need three feet of foam to attenuate low frequencies?
Leaky is not well damped. Leaky only acts on the zeroith mode, nothing above that. My room is very well sealed and very well damped. What most people do is the other way around (as you are suggesting) and no it doesn't work well that way.
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dewardh,
I would think that a leaky room would be very frequency dependent in the filter response of that method. Something like a bandpass loading of a bass enclosure, a narrow band filter only? And my neighbors complain without adding a leak, just the fact that you have fun containing low frequencies through many large glass windows besides the transfer through the ground plane from one slab construction house into another. The only part they do hear is the bass and that gets old fast if you are the one having to listen.
I would think that a leaky room would be very frequency dependent in the filter response of that method. Something like a bandpass loading of a bass enclosure, a narrow band filter only? And my neighbors complain without adding a leak, just the fact that you have fun containing low frequencies through many large glass windows besides the transfer through the ground plane from one slab construction house into another. The only part they do hear is the bass and that gets old fast if you are the one having to listen.
My speakers are direct radiators below 800 Hz. They are large so they still have directivity at the upper edge, but they become wide below about 500 Hz. It takes a lot of foam to do anything below 500 Hz. And there is always some backward wave propagation. In fact there is always a hot spot at exactly 180 degrees, even at HFs. I see this all the time.
Perhaps - but that still does not mean that it is well damped. It could be highly resonant transmissibility. It most likely would be unless something was done to damped it.
Why not simply build the speakers into the wall or at least move them as close as possible to the wall?