After reading Dr Earl's book Premium Home Theatre - design and construction I have concluded that the best approach to high fidelity reproduction of movies in a room includes:
1. a fairly live room to give a sense of spaciousness with diffusing treatment of walls and minimal absorptive treatment
2. speakers which can handle high output and that have constant directivity - as in comercial cinemas
I'd like to extend the use to music as well and I'm not totally satisfied that compression drivers can do this, so I'd like to hear views on the three candidates that stand out most:
1. high efficiency high output speakers designed for constant directivity - here's an example:
2. open baffle speakers - 3 way with multiple drivers to obtain high output - which are also constant directivity speakers as I understand (here I'm thinking Linkwitz Phoenix and here is an example:
3. line arrays - how do they compare?
What is your preference and why?
1. a fairly live room to give a sense of spaciousness with diffusing treatment of walls and minimal absorptive treatment
2. speakers which can handle high output and that have constant directivity - as in comercial cinemas
I'd like to extend the use to music as well and I'm not totally satisfied that compression drivers can do this, so I'd like to hear views on the three candidates that stand out most:
1. high efficiency high output speakers designed for constant directivity - here's an example:
An externally hosted image should be here but it was not working when we last tested it.
2. open baffle speakers - 3 way with multiple drivers to obtain high output - which are also constant directivity speakers as I understand (here I'm thinking Linkwitz Phoenix and here is an example:
3. line arrays - how do they compare?
An externally hosted image should be here but it was not working when we last tested it.
What is your preference and why?
I've found that the natural open sound of OB's is perfect for both HT and music. To really appreciate the difference you need to A/B OB with speakers in a box. Both dialogue and music are more natural. Going a step further and combining OB in a line array gives the same natural sound, but bigger. If your HT uses a projector and a big screen, then a line array works great. A big line array and a TV isn't going to work because the sound will dwarf the image. Also, a center channel may be problematic with an array unless you make it the width of your seating area because when you turn an array on its side the sound is seriously attentuated left or right of the last drive in the array.
Alot will depend on your budget. The right very cheap drivers can be amazing in an OB array. The right more expensive drivers can be amazing on OB in a single driver setup.
I started with Adire HE8.1 kits for my HT ($300/pr). Nice sounding, detailed and efficient bookshelf sized ported speakers. The bass rolls off at 80hz, but that's no problem with a sub. Then I started experimenting with OB line arrays and instantly I'm hooked on OB and that's with $1.50 drivers. Add a super tweeter since the cheapies roll off at 10500hz and I've got a great sounding speaker.
So I decided to try the HE8.1 drivers on OB and they sounded really thin because, due to their low Qts, they couldn't make bass on OB, at least without EQ. I didn't give up and found some 6" TV drivers for $3/ea that made bass on OB and tested them as bass support for the HE8.1 driver and that made all the difference. Now I'm in the process of building 5 dipoles using excotic hardwood available here in Costa Rica using the HE8.1 drivers with 4 of the cheap TV drivers in a W baffle in the bottom for a compact unit with great OB sound.
In A/B testing, the cheap array and the HE8.1 dipole prototype both blow the box sound away. The super cheap array struggles at very high volumes, but at moderately loud volumes the big tall soundstage is great. The dipole HE8.1 sounds much bigger, more natural and open than the boxed version and doesn't struggle at very high volumes, but otherwise the array beats it as far as "big" sound goes.
Alot will depend on your budget. The right very cheap drivers can be amazing in an OB array. The right more expensive drivers can be amazing on OB in a single driver setup.
I started with Adire HE8.1 kits for my HT ($300/pr). Nice sounding, detailed and efficient bookshelf sized ported speakers. The bass rolls off at 80hz, but that's no problem with a sub. Then I started experimenting with OB line arrays and instantly I'm hooked on OB and that's with $1.50 drivers. Add a super tweeter since the cheapies roll off at 10500hz and I've got a great sounding speaker.
So I decided to try the HE8.1 drivers on OB and they sounded really thin because, due to their low Qts, they couldn't make bass on OB, at least without EQ. I didn't give up and found some 6" TV drivers for $3/ea that made bass on OB and tested them as bass support for the HE8.1 driver and that made all the difference. Now I'm in the process of building 5 dipoles using excotic hardwood available here in Costa Rica using the HE8.1 drivers with 4 of the cheap TV drivers in a W baffle in the bottom for a compact unit with great OB sound.
In A/B testing, the cheap array and the HE8.1 dipole prototype both blow the box sound away. The super cheap array struggles at very high volumes, but at moderately loud volumes the big tall soundstage is great. The dipole HE8.1 sounds much bigger, more natural and open than the boxed version and doesn't struggle at very high volumes, but otherwise the array beats it as far as "big" sound goes.
Hi Paul,
I haven't read the book, but always thought that for movies you'd need a 'deader' room than for music - reason being that they use the surrounds to give ambience, meaning no need for a 'live room'.
I *think* I read it in the master handbook of acoustics (F. Alton Everest)
JBL's speaks found in many theaters over here (UK) are twin ported 15's crossed at 500Hz to a horn for the mid/highs. (for the L/C/R), and twin 18's for subs.
Off to look at that link for the book you mentioned.
Cheers
Rob
I haven't read the book, but always thought that for movies you'd need a 'deader' room than for music - reason being that they use the surrounds to give ambience, meaning no need for a 'live room'.
I *think* I read it in the master handbook of acoustics (F. Alton Everest)
JBL's speaks found in many theaters over here (UK) are twin ported 15's crossed at 500Hz to a horn for the mid/highs. (for the L/C/R), and twin 18's for subs.
Off to look at that link for the book you mentioned.
Cheers
Rob
Paul,
Something to take into consideration is that you NEVER hear anyone say that any other type of speaker sounds more natural for dialogue and vocals than OB or other dipoles. That's because they all impart some type of "boxy" coloration to the sound and in a side by side comparison they sound like a box is making the sound. The difference is most apparent when listening to a single speaker and that's where most of your sound comes from in HT, your center channel.
While I know there are outstanding box speakers and horns, which are better than dipoles for certain applications and I'm sure many of them play great sounding musci. eg If you want razor sharp imaging that surpasses reality, there are box designs that are better than dipole, but that would only work perfectly for a one person HT audience and once you go to a 5.1 setup that imaging is likely to be lost. That's not to say the dipoles don't image well. They just put the singer up front where they belong and the other instruments in their proper soundstage locations.
A lot would depend on your tastes as well. If you want music to play at extreme levels with chest pounding dynamics that you can feel, then something like that 1st setup pictured or horns would be the way to go. For the HT effects you can always combine dipole subs to get the natural bass sound supported by a sealed monopole to cover the lowest frequencies.
I'm sorry if I come accross as preaching, but I only discovered dipoles very recently and the results I've gotten using super cheap drivers, which by the way did take alot of searching and listening, and components from a relatively cheap speaker kit all connected to mid-fi components, has simply astounded me.
Something to take into consideration is that you NEVER hear anyone say that any other type of speaker sounds more natural for dialogue and vocals than OB or other dipoles. That's because they all impart some type of "boxy" coloration to the sound and in a side by side comparison they sound like a box is making the sound. The difference is most apparent when listening to a single speaker and that's where most of your sound comes from in HT, your center channel.
While I know there are outstanding box speakers and horns, which are better than dipoles for certain applications and I'm sure many of them play great sounding musci. eg If you want razor sharp imaging that surpasses reality, there are box designs that are better than dipole, but that would only work perfectly for a one person HT audience and once you go to a 5.1 setup that imaging is likely to be lost. That's not to say the dipoles don't image well. They just put the singer up front where they belong and the other instruments in their proper soundstage locations.
A lot would depend on your tastes as well. If you want music to play at extreme levels with chest pounding dynamics that you can feel, then something like that 1st setup pictured or horns would be the way to go. For the HT effects you can always combine dipole subs to get the natural bass sound supported by a sealed monopole to cover the lowest frequencies.
I'm sorry if I come accross as preaching, but I only discovered dipoles very recently and the results I've gotten using super cheap drivers, which by the way did take alot of searching and listening, and components from a relatively cheap speaker kit all connected to mid-fi components, has simply astounded me.
Given that this discussion focuses on the "ultimate" I think a large screen would be in order! ... but this is a good point that John makes regarding using an array and a TV - it would be a mismatch.
I'm very interested in open baffle speakers. The aspect about them that interest me most in home theatre is this - constant directivity. Normallly this is achieved with horns. Which I think is fine for home theatre, but I'm suspicious of the coloration aspect. This is where dipoles seem to shine, however it seems expensive to be able to get high output.
Back to constant directivity - I think this is often overlooked. HT rooms are normally made to be dead because the off axis frequency response (or the power response) is not as well bahaved as the on axis response. This means that the reflected sound is coloured. Therefore with monopole speakers the room must be relatively dead, more so for home theatre. But with dipole and horns this is different:
1. their power response is such that the off axis sound is not as coloured
2. there is less off axis sound as they are more directional
3. dipoles - the reflected sound from the rear is delayed so that it is perceived as ambience rather than messing up the imaging
In the fidelity department, dipoles now start to look even better. It seems their main disadvantage is the cost and difficulty in design - to be able to get them high output compounds these difficulties and further adds to the cost.
I'm very interested in open baffle speakers. The aspect about them that interest me most in home theatre is this - constant directivity. Normallly this is achieved with horns. Which I think is fine for home theatre, but I'm suspicious of the coloration aspect. This is where dipoles seem to shine, however it seems expensive to be able to get high output.
Back to constant directivity - I think this is often overlooked. HT rooms are normally made to be dead because the off axis frequency response (or the power response) is not as well bahaved as the on axis response. This means that the reflected sound is coloured. Therefore with monopole speakers the room must be relatively dead, more so for home theatre. But with dipole and horns this is different:
1. their power response is such that the off axis sound is not as coloured
2. there is less off axis sound as they are more directional
3. dipoles - the reflected sound from the rear is delayed so that it is perceived as ambience rather than messing up the imaging
In the fidelity department, dipoles now start to look even better. It seems their main disadvantage is the cost and difficulty in design - to be able to get them high output compounds these difficulties and further adds to the cost.
I have actually experimented with dipoles a tad. I put my pair of AV12's in a H frame but found that they didn't quite fare like I would have hoped. I suspect they have some breakup that the 2nd order crossover wasn't enough to tame, that I might need a notch filter, and they seem to move so much air that even the fairly open cast basket makes air noise. It's extremely difficult to make a driver with 46mm pp xmax that won't make noise in open baffle.
I had also tried it with some car speakers. The cheap mylar tweeters messed things up a bit, but the did sound quite reasonable for what they were. I'd like to do a proper test of dipole though.
I had also tried it with some car speakers. The cheap mylar tweeters messed things up a bit, but the did sound quite reasonable for what they were. I'd like to do a proper test of dipole though.
Paul,
I think you have some misconceptions about dipoles. First, they are more efficient than monopoles because the back wave from each driver is used. Yes, if you want dipole down into the LFE bass range it is more difficult to design (active EQ's etc.), but that can be covered by a sub in a box. For the higher frequencies it's easier than boxed speakers (no volumes to compute, no ports, etc.) , just a baffle width to consider for bass rolloff. Plus you can experiment using cardboard, so you can hear your designs before starting any construction. Cost wise it can be done very very cheap using arrays of cheap drivers with great results because each does only a little work. The only difficult part is that driver selection is more limited because you need higher Qts drivers.
I think you have some misconceptions about dipoles. First, they are more efficient than monopoles because the back wave from each driver is used. Yes, if you want dipole down into the LFE bass range it is more difficult to design (active EQ's etc.), but that can be covered by a sub in a box. For the higher frequencies it's easier than boxed speakers (no volumes to compute, no ports, etc.) , just a baffle width to consider for bass rolloff. Plus you can experiment using cardboard, so you can hear your designs before starting any construction. Cost wise it can be done very very cheap using arrays of cheap drivers with great results because each does only a little work. The only difficult part is that driver selection is more limited because you need higher Qts drivers.
johninCR said:
Not at all.....
There are 2 approaches to dipoles:
1. conventional approach using high Qts drivers
2. Linkwitz approach
I favour the second approach.
The output of a dipole is much more limited by displacement. This is why Linkwitz Orion uses an 8" driver to get to 100 Hz with a 4th order rolloff. Yes, there is the rear wave reinforcement of the midrange but whether or not this translates into higher output in practical terms is another matter. For this to give higher output you would need something more like a 4 way speaker. If you look at the Linkwitz approach, it is really quite involved.
Here Linkwitz describes his approach
Linkwitz discussion of sensitivity for his Phoenix speaker is interesting:
Phoenix efficiency
2.83V sensitivity
tweeter: 90 db (SS D2904/9800)
midrange: 103 db above 250 Hz(2 x SS21W/8554 in parallel)
96 db @ 100 Hz
woofer: 97 db @ 120 Hz rolling off at 6db/octave (2 x Madisound 1252DVC)
91 db @ 60 Hz
85 db @ 30 Hz
It's interesting to note how the midrange efficiency is very high. If only the midrange was operated in dipole mode then it becomes easier to get high output. However, some may also argue that one of the strongest aspects of open baffle is the uncoloured boxless bass which doesn't excite as many room modes. However, for home theatre where a lot of the bass is noise, then perhaps monopole is the way to go, with the focus being on the uncoloured midrange of open baffle for voices.
Thanks, John, this has gotten me thinking a lot more .....
paulspencer said:
After reading the book, you should have realised you paid x amount of dollars for someone to tell you their side of the story. After living a long life you realise that only you can tell yourself the true side of the story.
The point being that everyone has their belief in whats best. Each speaker company has graphs telling why their design is superior, every computer geek has some theory about why his 733 Mhz Duron overclocked to 1.2Ghz with a $250 water cooling system is somehow better than the $200 2.8Ghz/Mobo combo down at Fry's. Its the nature of poeple.
Just get out there and start experimenting, let some of us make the financial mistake of trying stuff out. Then you'll be able to make a really good and reliable decision.
BTW: Nice pictures!
I find that dipoles introduce inaccurate spacial cues, if placed too close to the wall. Yes it's a natural effect (most sound producing objects radiate in all directions, hence the natural nature of vocals), but for HT it can wreck the illusion of space that a good soundfield creates.
YMMV, but it's a concern of mine with regards to elaborate soundmixes.
If you can get a dipole far enough away from a wall and/or make that wall absorptive, then it is the way to go for HT use.
YMMV, but it's a concern of mine with regards to elaborate soundmixes.
If you can get a dipole far enough away from a wall and/or make that wall absorptive, then it is the way to go for HT use.
Re: Re: Ultimate HT and music speakers
And I did realise ..... having seen Dr Earl's point of view expressed on the bass list I was aware that it would be his opinion, but it was also well supported and described. Unsupported opinions aren't much help when you are familiar with what is out there already, but if someone expresses their view and backs it up well, it gives you a chance to weigh it up against your own point of view.
I'm not sure why you presume that I'm not already doing this. The door is always for someone to say "just get out there and start trying things" in any discussion on this forum, and it is a valid suggestion, but it can also be used to short circuit some very valid and worthwhile discussions. It can be discussions like these that can help people to understand WHY something works or doesn't work.
YMMV, what does this mean? (It amazes me how many such abbrev's us audio guys use!!!)
Linkwitz recommends placing them at least a metre out from a rear wall. I have just had a look back at his site and read up again on placement and his suggestions are interesting. If the distance behind the dipole and the distance from the listener to the rear wall is equal, then the rear reflection is cancelled. It is shown in this diagram:
It shows the plan of the room with reflections shown as virtual dipoles D1-4. and is described here
Hybrid fourdoor said:
And I did realise ..... having seen Dr Earl's point of view expressed on the bass list I was aware that it would be his opinion, but it was also well supported and described. Unsupported opinions aren't much help when you are familiar with what is out there already, but if someone expresses their view and backs it up well, it gives you a chance to weigh it up against your own point of view.
Hybrid fourdoor said:
I'm not sure why you presume that I'm not already doing this. The door is always for someone to say "just get out there and start trying things" in any discussion on this forum, and it is a valid suggestion, but it can also be used to short circuit some very valid and worthwhile discussions. It can be discussions like these that can help people to understand WHY something works or doesn't work.
Mudge said:
YMMV, what does this mean? (It amazes me how many such abbrev's us audio guys use!!!)
Linkwitz recommends placing them at least a metre out from a rear wall. I have just had a look back at his site and read up again on placement and his suggestions are interesting. If the distance behind the dipole and the distance from the listener to the rear wall is equal, then the rear reflection is cancelled. It is shown in this diagram:
An externally hosted image should be here but it was not working when we last tested it.
It shows the plan of the room with reflections shown as virtual dipoles D1-4. and is described here
YMMV = Your Mileage May Vary
In an ideal world I'd agree with Linkwitz about the positioning, and I do like the dipole sound for studio recorded music, it really does make the speakers disappear and stick the performers right in your room.
I think dipoles suit the reproduction of music recorded with very directional mics or in very dead rooms with an omnipolar mic much better than they do a piece recorded in a live room with omnipolar mics.
In an ideal world I'd agree with Linkwitz about the positioning, and I do like the dipole sound for studio recorded music, it really does make the speakers disappear and stick the performers right in your room.
I think dipoles suit the reproduction of music recorded with very directional mics or in very dead rooms with an omnipolar mic much better than they do a piece recorded in a live room with omnipolar mics.
Yes dipoles are harder to accomodate because you need space behind them for the rear wave not to become a huge problem. But appart from that dialogue, as has been commented on here before, is much more natural. I made my speaker dipole and the thing that really hit me was how natural speach was. People speaking on the TV sounded more like how people actually talk.
Dipole are more efficient because you dont need to factor in baffle step. IF you use the dipole above the frequency where dipole cancellation occurs. If you dont then you need to use linkwitz approach of active EQ to boost the 6dB roll off per octave when this occurs. So your dipole actually becomes not efficient at all. This is not much worry really just use a boxed bass driver to cover say 200-300 down to say 80hz and then use a sub to cover the rest. Utilising the dipole roll off into the xover for the highpass on the midrange.
Dipole are more efficient because you dont need to factor in baffle step. IF you use the dipole above the frequency where dipole cancellation occurs. If you dont then you need to use linkwitz approach of active EQ to boost the 6dB roll off per octave when this occurs. So your dipole actually becomes not efficient at all. This is not much worry really just use a boxed bass driver to cover say 200-300 down to say 80hz and then use a sub to cover the rest. Utilising the dipole roll off into the xover for the highpass on the midrange.
One aspect that has been mentioned that I'm interested in is the imaging of dipoles......
John this appears contradictory: some box speakers have rajor sharp imaging but dipoles on the other hand put everything in their proper soundstage locations. How are they different? Do dipoles have a wider sweet spot?
I would have thought that dipoles would in fact have significantly better imaging due to the interaction with the room and the reduction of early reflections which confuse accurate imaging in conventional speakers.
I find this comment interesting as I anticipate those who want dipoles would in fact be particularly interested in listening to live recrordings. How is it that they aren't suitable for live recordings? What is the diffference to conventional speakers here?
johninCR said:
John this appears contradictory: some box speakers have rajor sharp imaging but dipoles on the other hand put everything in their proper soundstage locations. How are they different? Do dipoles have a wider sweet spot?
I would have thought that dipoles would in fact have significantly better imaging due to the interaction with the room and the reduction of early reflections which confuse accurate imaging in conventional speakers.
Mudge said:
I find this comment interesting as I anticipate those who want dipoles would in fact be particularly interested in listening to live recrordings. How is it that they aren't suitable for live recordings? What is the diffference to conventional speakers here?
If you think about how the human ear works, it is very easy to understand the appeal of a multipolar speaker. The ear/auditory complex is at it's simplest a phase and time discriminator.
Just going with a monopolar treble, you have a discrete source that radiates in one direction only, and all the reflections occur closer to you than the source. It's like someone shining a torch at your eyes. You might be able to see a bit to the side and up & down, but nothing behind the torch.
A dipole/bi-pole (the radiation patterns are similar but not identical at HF) is more like a lantern, you get reflections from surfaces behind the speaker, and because you've got a huge reflecting wall, the light is not as obvious.
Now if your source material is devoid of auditory cues about the environment to the rear of the sound-sources, and you play it back through a speaker which is similar, that's an incredibly unnatural sound. The best analogy I can think is someone standing on the porch of a snowed in cabin/house, where all the reflections come from in front of the speaker. How often does that happen?
What I've just described is most studio produced music, especially vocals. You have an apparently monopolar source which the brain thinks should have some cues as to it's position. Once a dipole has added those, the brain gets on with figuring out where everything should be in the soundstage, hence the great imaging qualities of a good dipole.
With a live recording, such as dialogue in a movie, or an orchestra in a concert hall, the recording itself should have enough auditory cues that there's no need to add any. There might not be enough, or the room might swamp them, so the lessened interaction out of the speaker axis of a dipole might be beneficial in that case.
So for studio music, dipoles would be the way to go, for those with a soundscape, monopoles in the nearfield would be my choice.
Just going with a monopolar treble, you have a discrete source that radiates in one direction only, and all the reflections occur closer to you than the source. It's like someone shining a torch at your eyes. You might be able to see a bit to the side and up & down, but nothing behind the torch.
A dipole/bi-pole (the radiation patterns are similar but not identical at HF) is more like a lantern, you get reflections from surfaces behind the speaker, and because you've got a huge reflecting wall, the light is not as obvious.
Now if your source material is devoid of auditory cues about the environment to the rear of the sound-sources, and you play it back through a speaker which is similar, that's an incredibly unnatural sound. The best analogy I can think is someone standing on the porch of a snowed in cabin/house, where all the reflections come from in front of the speaker. How often does that happen?
What I've just described is most studio produced music, especially vocals. You have an apparently monopolar source which the brain thinks should have some cues as to it's position. Once a dipole has added those, the brain gets on with figuring out where everything should be in the soundstage, hence the great imaging qualities of a good dipole.
With a live recording, such as dialogue in a movie, or an orchestra in a concert hall, the recording itself should have enough auditory cues that there's no need to add any. There might not be enough, or the room might swamp them, so the lessened interaction out of the speaker axis of a dipole might be beneficial in that case.
So for studio music, dipoles would be the way to go, for those with a soundscape, monopoles in the nearfield would be my choice.
It sounds like Mudge has more knowlege and experience with all this stuff than I. From what I have read from others who have the right system with single driver monopole, tube set ups, the right wiring and source, and room setup that you can acheive an imaging and soundstage that far surpasses reality in terms of imaging. It becomes a holographic effect in a very small sweet spot. I understand that this is much more difficult with dipole, however, a friend has a dipole line array on a concave baffle focused into his nearfield sweet spot who getting that kind of imaging. His rear wall behind the speakers is over 12ft away, so I think he really gives up the dipole effect and just ends up with a boxless sound focused into his listening position.
Now keep in mind that I'm using high midfi to get the signal to my speakers. I've used both line arrays and a single coincident driver in boxes and in dipole using the same drivers and system. All of my dipoles use swept back trapezoidal wings to reduce the size to more normal speaker size with a cap on top to reduce early ceiling reflections. I've A/B tested them with the following comments:
The dipole has a bigger more open sound with more pronounced vocals that are much clearer and more natural sounding. Arrays add another magnitude of size but on occasion bigger than real (eg Barry White sounds like his head is 3ft in diameter with my array).
The soundstage is taller and deeper with the dipoles and again the array adds to that.
The dipole image is not as sharp as the monopoles. It's not blurry, just a little fuzzy around the edges. I've yet to experiment with treating the wall behind the speakers, but polyfill behind the driver to absorb some of the HF did improve the image. The monopole image is sharper but in a smaller sweet spot. The array adds another degree of fuzziness due to the different distances of the drivers to your ears.
Off axis I like the dipoles more and the array more than the single driver.
I haven't noticed any big difference with live verses studio recordings, but I don't have any high quality live recordings to compare.
For movies I find the dialogue much clearer and natural with dipole. I also find that the dipoles do a better job of recreating the room where the dialogue is taking place, which makes sense to me because they recreate the venue much better for music.
I hope my 2 cents is of help. I'm new to all of this and definitely no expert, but I'm a fast learner.
Now keep in mind that I'm using high midfi to get the signal to my speakers. I've used both line arrays and a single coincident driver in boxes and in dipole using the same drivers and system. All of my dipoles use swept back trapezoidal wings to reduce the size to more normal speaker size with a cap on top to reduce early ceiling reflections. I've A/B tested them with the following comments:
The dipole has a bigger more open sound with more pronounced vocals that are much clearer and more natural sounding. Arrays add another magnitude of size but on occasion bigger than real (eg Barry White sounds like his head is 3ft in diameter with my array).
The soundstage is taller and deeper with the dipoles and again the array adds to that.
The dipole image is not as sharp as the monopoles. It's not blurry, just a little fuzzy around the edges. I've yet to experiment with treating the wall behind the speakers, but polyfill behind the driver to absorb some of the HF did improve the image. The monopole image is sharper but in a smaller sweet spot. The array adds another degree of fuzziness due to the different distances of the drivers to your ears.
Off axis I like the dipoles more and the array more than the single driver.
I haven't noticed any big difference with live verses studio recordings, but I don't have any high quality live recordings to compare.
For movies I find the dialogue much clearer and natural with dipole. I also find that the dipoles do a better job of recreating the room where the dialogue is taking place, which makes sense to me because they recreate the venue much better for music.
I hope my 2 cents is of help. I'm new to all of this and definitely no expert, but I'm a fast learner.
Mudge said:
Mudge, let me see if I understand the point that you are making. Live recordings include a lot of ambient sound reflected around the room in which it is recorded. In this case you prefer monopoles, which add a minimum of ambience. Ideally this would be in a room with treament to minimise reflections.
Studio recordings may be more dead, although they often have a certain amount of ambience added either digitally or in the recording studio itself. In this case you prefer dipoles as they add some additional ambience.
This is my understanding of what you have written.
However, I'm not too sure about the connection here with imaging. I see it as two separate issues.
Dipoles add ambience it is true. But the reflections within the listening room from a dipole and a monopole are of a different nature. Monopole speaker reflections are more coloured than those from dipoles due to the power response being less well behaved and therefore should be avoided more.
However, the amount of reflected sound with monopoles will normally be more than dipoles except for the wall behind the speakers. This may be attenuated in the midrange if desired by damping if desired, but given correct placement there is usually sufficient delay between these reflections that the brain is able to distinguish it as ambience, so imaging is not confused.
Early reflections from monopoles on the other hand tend to confuse stereo imaging.
johninCR said:
This doesn't sound like an apples to apples comparison to me. Compare a single driver dipole to a single driver monopole and I'd expect the dipole to have better imaging. I would be very interested to hear such a comparison ... I expect that the reason for the imaging of single driver speakers is that they more closely reach the idea of a point source.
johninCR said:
Dipole effect? The polar response and power response is still the same. Efficiency is given up and there would be less ambience but in terms of accuracy, the reduced reflections and the reduction of room mode excitation would remain.
johninCR said:
Your comments have gotten me thinking quite a lot more about dipoles in fact. I find the learning process is a big part of the fun.
Paul,
imaging is a funny thing, you want a good amount of reflections, with a consistent frequency response to arrive at the ear to give it something to work with. But those reflections really should be in the original recording, not coming from the room.
If there aren't any, it's better if they come from the wall behind the speaker, rather than from the side walls, because one gives the soundstage a sense of depth, the other restricts it's width.
My personal choice would be monopolar line arrays, because of the huge nearfield advantage over quasi-point sources.
Failing that, I'm a big fan of the Quad ESL-63/988/989s, because of their near-perfect point source reproduction.
imaging is a funny thing, you want a good amount of reflections, with a consistent frequency response to arrive at the ear to give it something to work with. But those reflections really should be in the original recording, not coming from the room.
If there aren't any, it's better if they come from the wall behind the speaker, rather than from the side walls, because one gives the soundstage a sense of depth, the other restricts it's width.
My personal choice would be monopolar line arrays, because of the huge nearfield advantage over quasi-point sources.
Failing that, I'm a big fan of the Quad ESL-63/988/989s, because of their near-perfect point source reproduction.
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