How do you get good imaging? - Page 9 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th August 2011, 01:45 AM   #81
diyAudio Member
 
Join Date: Feb 2006
Location: usa
Blog Entries: 1
gedlee, probably I just never heard that type of imaging you are describing.
but I do like effect of physically separated speakers.
hopefully, some time, I'll get a chance to auditition pair of your loudspeakers.
  Reply With Quote
Old 10th August 2011, 02:33 AM   #82
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Quote:
Originally Posted by MisterTwister View Post
hopefully, some time, I'll get a chance to auditition pair of your loudspeakers.
You should, they're quite good.

Quote:
Originally Posted by gedlee View Post
Diffraction and early reflections have a significant effect on imaging.
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.
__________________
Take the Speaker Voltage Test!
  Reply With Quote
Old 10th August 2011, 01:26 PM   #83
diyAudio Member
 
DBMandrake's Avatar
 
Join Date: Nov 2010
Location: Glasgow, UK
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.
__________________
- Simon

Last edited by DBMandrake; 10th August 2011 at 01:34 PM.
  Reply With Quote
Old 10th August 2011, 03:17 PM   #84
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Hmmm..... can't say I've really noticed that, but it's worth investigation. Thanks for the lead.
  Reply With Quote
Old 10th August 2011, 03:50 PM   #85
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
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.
Attached Images
File Type: jpg Living room.jpg (74.6 KB, 155 views)
  Reply With Quote
Old 10th August 2011, 03:55 PM   #86
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
Here's the 3D doll house view.
Attached Images
File Type: jpg Living room dollhouse.jpg (54.0 KB, 156 views)
  Reply With Quote
Old 11th August 2011, 02:06 PM   #87
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
Quote:
Originally Posted by gedlee View Post
What you are talking about is "headphone" style imaging, which is, yes, rather precise, but lacks any kind of room ambiance. Getting the room involved adds to the spaciousness feeling, but also make imaging much more difficult. The "equipment rack or a TV between" the main speakers is a real degradation in imaging due to the diffraction from these objects. And I would disagree completely with the later part of this statement: "Diffraction and early reflections may color sound but I didn't find them to affect imaging." Diffraction and early reflections have a significant effect on imaging.

Maybe we are not talking about or looking for the same things. I am not looking for "headphone" imaging in my room - the "you are there" effect. I want the sound to appear to be in the room with me, not the other way arround.
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.
  Reply With Quote
Old 11th August 2011, 02:28 PM   #88
diyAudio Member
 
DBMandrake's Avatar
 
Join Date: Nov 2010
Location: Glasgow, UK
Quote:
Originally Posted by dirkwright View Post
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.
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.
Quote:
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.
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.
__________________
- Simon

Last edited by DBMandrake; 11th August 2011 at 02:32 PM.
  Reply With Quote
Old 11th August 2011, 02:35 PM   #89
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
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?
  Reply With Quote
Old 11th August 2011, 03:27 PM   #90
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Yes. CARA. I use it and it's very nice. The more detail you feed it, the better the simulation - and the longer the calculation times.

Your corner set-up looks wide to me. I'd be afraid of the "hole in the middle" effect.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
imaging jj Multi-Way 2 5th July 2009 12:30 PM
Imaging... retiredmxer Multi-Way 19 21st April 2007 04:12 AM
Horn Imaging gpsmithii Full Range 1 3rd June 2005 03:20 PM


New To Site? Need Help?

All times are GMT. The time now is 03:23 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2