You should, they're quite good.
Sure do. I've found that "good diffraction" behind the speakers tends to make that wall vanish, giving greater depth. Something like a Schroeder Diffuser or some of the RPG products. It can also be done with a very absorbent wall, but I prefer the diffraction.
My taste runs more to the "You' are there" type presentation rather than the "They are here" type. I like both, but the opening up of the space and sound of different acoustic venues is what really floats my boat. An acoustic virtual reality trip.
I'm surprised nobody mentioned frequency response flatness, which is an important part of imaging due to the brain using our ears HRTF as a large contributory factor in determining where a sound is coming from, particularly above ~2Khz where changes in frequency response with direction from the ear start to get most dramatic.
No matter how good the speaker is in other ways (polar response, minimal diffraction effects etc) if the basic frequency response balance is wrong in certain specific ways, it will kill the imaging dead, as it provides contradictory and confusing HRTF cues to the brain. (Some cues say the sound is coming from one direction, other cues say the same sound is coming from somewhere else, and the whole "imaging" illusion in our brain falls apart)
For example, a big dip in the presence region between ~2-5Khz is a sure fire way to get a speaker that doesn't image well, similarly a poorly implemented crossover somewhere in this frequency region will do the same thing, especially if the dip is a result of phase cancellation between the drivers.
Extra attention paid to frequency response flatness through the presence region is needed for good "you are there" imaging IMHO. It's surprising how much a small error in response in this region affects the overall presentation of the sound.
Likewise, frequency response flatness through the midrange whilst not quite as critical is still rather important. There's quite a small difference in overall frequency response between a speaker that sounds "ok" and one that sounds great.
No matter how good the speaker is in other ways (polar response, minimal diffraction effects etc) if the basic frequency response balance is wrong in certain specific ways, it will kill the imaging dead, as it provides contradictory and confusing HRTF cues to the brain. (Some cues say the sound is coming from one direction, other cues say the same sound is coming from somewhere else, and the whole "imaging" illusion in our brain falls apart)
For example, a big dip in the presence region between ~2-5Khz is a sure fire way to get a speaker that doesn't image well, similarly a poorly implemented crossover somewhere in this frequency region will do the same thing, especially if the dip is a result of phase cancellation between the drivers.
Extra attention paid to frequency response flatness through the presence region is needed for good "you are there" imaging IMHO. It's surprising how much a small error in response in this region affects the overall presentation of the sound.
Likewise, frequency response flatness through the midrange whilst not quite as critical is still rather important. There's quite a small difference in overall frequency response between a speaker that sounds "ok" and one that sounds great.
Last edited:
Since the room apparently plays a role in imaging, how does this arrangement look? The two triangular objects in the corners would be loudspeakers designed for corner placement, and the rectangular box in the third corner is a subwoofer. I'm thinking of changing my living room to this arrangement by adding a wall so that I get two good corners.
Attachments
When I think of headphone imaging, obviously I think of the image space being in my head, between my ears. I have never had that experience with freestanding loudspeakers. The soundstage always appears to be in front of me, between the speakers.
If putting the hifi equipment between the speakers is bad, is there anything that's allowed between them? If I'm planning on using two good corners for the speakers, it seems like incredibly wasted space to not be able to put something against the wall between the two speakers. Most folks don't have the luxury of wasting space like that.
Also, I think the terms "diffraction" and "reflection" are being used interchangeably when they are different things. My understanding is that diffraction only occurs at the edge of a speaker cabinet, usually the front panel (or baffle) is the one of most concern. Everything else that the sound hits in the room is a reflection.
Most living rooms would have a TV between the main speakers, and in the old days that would be a rather bulky and deep CRT screen. I think as long as the front of the speakers are at least 6 inches or so in front of the front face of the TV you won't get any significant problems with imaging from high frequency reflections.
You'd also want at gap of at least a foot, preferably 2 between each speaker and the TV so that the TV wouldn't add extra baffling to the speaker - effectively lowering its baffle step frequency, causing a boost in the low midrange upper bass region. (More so a problem on a narrow baffle speaker than a wide baffle one) Such a boost in the low midrange can give the impression of a loss of imaging if the speakers frequency response balance was correct before the nearby baffling influence changed things.
As you say, not many people can afford to devote an entire wall to 2 speakers, but as long as the front of the speakers are the front most objects along that wall and not immediately flanked by other objects practically speaking you'll be fine.
There is nothing magic about a speaker baffle that causes diffraction that cant happen anywhere else - diffraction is when a sound wave is travelling along a boundary like a baffle, which then abruptly changes direction (like a right angle at the edge of a cabinet) causing an expansion and re-radiation of the wave.
If you had your speakers relatively near a TV screen and roughly in line with it, some of the radiation of the speakers would travel along the face of the tv screen and then diffract off the edge as it leaves the screen...likewise abrupt changes in geometry of the room near the speakers such as alcoves or cabinets can have sharp edges for the signal to diffract off.
Both reflection and diffraction are going on in a room.
Last edited:
Yeah, you're right. I thought about it after I wrote my post and realized that there is probably at least some diffraction going on off of other sharp corners in the room, like cabinet and TV edges. I kind of think it would be very minor, or I'd have to have ears of pure gold to hear it.
I suppose a flat screen TV that mounts on the wall would be best for reducing these kinds of effects. I suppose also that all of the furniture in the listening room should have large radius corners...
Also, is there some kind of room mode simulation software out there that someone can recommend?
I suppose a flat screen TV that mounts on the wall would be best for reducing these kinds of effects. I suppose also that all of the furniture in the listening room should have large radius corners...
Also, is there some kind of room mode simulation software out there that someone can recommend?
In my expereince this is not true.
As I stated before I have gone to extremes to minimize reflections and diffraction of all kinds close to the speakers. The imaging that I achieve is widely held as the best that anyone has heard. It is not subtle, but there are lots of aspects to the problem. You won't hear room diffraction unless the speakers have none. But if the speakers are meticulous about controlling this problem then nearby objects in the room become the next problem (been there).
My "TV" is a screen that is acoustically transparent held in place by "almost nothing" - there is almost no diffraction at all in my design. By comparison a large screen TV would have significant reflection/diffraction. Basically in the entire 4 to 5 feet of the front of my room the only source of sound is the direct sound from the speakers - no back wall reflections, no nearby diffractions, no nothing. This attention to detail pays big dividends when it comes to imaging.
Hard to do? Of course it is!! Worth it? Only if you really want the very best sound possible, otherwise don't bother.
Maybe, maybe not. I mean you DO have to look for it and most setups have such poor impulse responses that it is hard to see anything, but I don't believe that it should be all that hard to find if you look for it. I just haven't actually tried - who has time!
People have asked to see impulse response measurements of my room - GREAT IDEA!! I just haven't had the time. Would love to do that sometime though.
Oh man, this whole discussion is starting to remind me of the argument I had with she who must be obeyed when we moved into this place. It's very hard to explain to someone who owns a Bose wave radio why a couch arm can't be poking out in front of a speaker.
Thats why I preach a "sound room". Give your wife the "living room"! As long as you get a room as well. You'll never get a decent system compromising over spaces where the wife lives.
Jeez, I wonder what this room looks like? Martha Stewart would probably faint....
If you walk into my theater and even pay the slightest attention to how it looks then you are completely missing the point. The lights go on when I enter, then off for everything else, then back on to leave. Otherwise the room is dark - thats best for listening and for watching movies. This room is by far everyones favorite room in the house. Its all about "entertainment".
Yeah, the eventuality is that I'll build an addition to my own specifications once we find our dream house to purchase. I've been planning it for years and it's going to be fantastic once I get to make it happen.
Uh, yeah, not really practical unless a lot of money is available. Particularly if you live in Europe, where living space is very expensive. I think most of us have to make due with major compromises.
Its not really that expensive, but it does take a bit of room. More than feasible here in North America, but not Europe. But the question of the thread is "How do I get good imaging?" not "How do I get good imaging when I have to compromise everything?" I can answer the first, but not the second.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.