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JBL 708P Review (Professional Monitor)

mac

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I had a set of these for six months or so and enjoyed them very much. Only two speakers have sounded better in my home, both of which cost more and are significantly larger.
 

T.J. McKenna

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I'd buy that reasoning if the 8-inchers were full range, but they're not -- both need a sub. I have a hard time believing that crossover at 55Hz instead of 45Hz makes it sound like a toy.

It depends how you define "full-range". If you mean flat to 20 Hz very few speakers qualify but if flat to 40 Hz qualifies then a powered pro monitor with an 8 inch can do the trick, far better than any 5 inch can. I have the 708's predecessor, the LSR6328P, along with TWO matching subwoofers, the LSR6312P, and I generally choose to use the 6328 by itself - partly for convenience, but also because at normal listening levels and music it pretty well duplicates what the full system can manage.
 

T.J. McKenna

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How do we measure image size, height, and scale? And how crucial are these to our listening experience? For me, the sense of lifelike scale is very important, particularly on "big" works like those of Mahler or Bruckner. And yet measurements tell us close to nothing about this aspect of reproduction. In fact, I would argue that you need a dose of inaccuracy to recreate the sense of scale. Take height, for instance: the more accurate the reproduction the less the sense of image height. How can stereo mikes capture the height you hear from live instruments and voices? It's only because speakers in a room are inaccurate that you get a sense of height - however spurious - that in some ways mimics what you hear in live music. Sometimes two wrongs can make - more or less - a right.
 

Richard Berg

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How do we measure image size, height, and scale? And how crucial are these to our listening experience? For me, the sense of lifelike scale is very important, particularly on "big" works like those of Mahler or Bruckner. And yet measurements tell us close to nothing about this aspect of reproduction. In fact, I would argue that you need a dose of inaccuracy to recreate the sense of scale. Take height, for instance: the more accurate the reproduction the less the sense of image height. How can stereo mikes capture the height you hear from live instruments and voices? It's only because speakers in a room are inaccurate that you get a sense of height - however spurious - that in some ways mimics what you hear in live music. Sometimes two wrongs can make - more or less - a right.
What? "Accurate" and "directional" are totally different things.

Your ears are encoding a 3D soundfield into 2 audio channels right now. You do have additional degrees of freedom that mic stands don't (move around the room, tilt your head), so the encoding is more of a lossy "projection" than a strict capture, but that projection obviously isn't limited to just left & right.

Designing stereo mic techniques that translate well to 2ch loudspeakers is a more complex topic, involving the polar patterns of both transducers and a healthy dose of acoustics, but nowhere in that math is inaccuracy a virtue.
 

RobL

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Looks like these have dropped a bit in price in Canada...see a couple of places selling them for CAD$2649, down from $3199-$3399. Still not as cheap as in the US but better than they were. Around the same price as Genelec 8350 now, I just need to decide which way to go.
 

T.J. McKenna

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What? "Accurate" and "directional" are totally different things.

Your ears are encoding a 3D soundfield into 2 audio channels right now. You do have additional degrees of freedom that mic stands don't (move around the room, tilt your head), so the encoding is more of a lossy "projection" than a strict capture, but that projection obviously isn't limited to just left & right.

Designing stereo mic techniques that translate well to 2ch loudspeakers is a more complex topic, involving the polar patterns of both transducers and a healthy dose of acoustics, but nowhere in that math is inaccuracy a virtue.

I'm not sure what you're getting at. My point is that there is no "height" in the recording but there is a sense of height in live music. And speakers do give varying impressions of height in playback, partly due to reflections from floor and ceiling and partly due to the radiating area of the speaker itself, and this is not in the recording itself. In other words, it is inaccurate. However, this "inaccuracy" actually simulates the height aspect of the original better than ostensibly accurate reproduction does.
 

Richard Berg

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My point is that there is no "height" in the recording
Of course there is. Studio floors are not anechoic. Microphone polar response doesn't drop instantaneously to 0 in the vertical plane.
 

Robbo99999

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How do we measure image size, height, and scale? And how crucial are these to our listening experience? For me, the sense of lifelike scale is very important, particularly on "big" works like those of Mahler or Bruckner. And yet measurements tell us close to nothing about this aspect of reproduction. In fact, I would argue that you need a dose of inaccuracy to recreate the sense of scale. Take height, for instance: the more accurate the reproduction the less the sense of image height. How can stereo mikes capture the height you hear from live instruments and voices? It's only because speakers in a room are inaccurate that you get a sense of height - however spurious - that in some ways mimics what you hear in live music. Sometimes two wrongs can make - more or less - a right.
I'm not sure what you're getting at. My point is that there is no "height" in the recording but there is a sense of height in live music. And speakers do give varying impressions of height in playback, partly due to reflections from floor and ceiling and partly due to the radiating area of the speaker itself, and this is not in the recording itself. In other words, it is inaccurate. However, this "inaccuracy" actually simulates the height aspect of the original better than ostensibly accurate reproduction does.
I just think that's rubbish. Random inaccuracies certainly aren't going to reproduce accurate height information. I think you're just barking up the wrong tree. To me that's all just a complete non-starter not worth discussing bar this quick comment.
 

Pearljam5000

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Looks like these have dropped a bit in price in Canada...see a couple of places selling them for CAD$2649, down from $3199-$3399. Still not as cheap as in the US but better than they were. Around the same price as Genelec 8350 now, I just need to decide which way to go.
Based on reliability alone
Genelec >JBL
 

T.J. McKenna

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Of course there is. Studio floors are not anechoic. Microphone polar response doesn't drop instantaneously to 0 in the vertical plane.

So how do microphones convey this sense of height and speakers play it back? If you recorded sounds on the recording studio ceiling and then on the floor would playback through speakers place the sounds on or above your ceiling and on the floor? I think not.
 

T.J. McKenna

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I just think that's rubbish. Random inaccuracies certainly aren't going to reproduce accurate height information. I think you're just barking up the wrong tree. To me that's all just a complete non-starter not worth discussing bar this quick comment.

Perhaps you should reread what I actually said. I stated that the height you get in playback is spurious and inaccurate but that it gives a sense of height that you get in live music but which the recording CANNOT, by its very nature, capture. My point is that sometimes inaccuracies can simulate the original sound more realistically, broadly speaking, than an ostensibly accurate reproduction.
 

T.J. McKenna

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I wish I could hear some Genelecs, not sure if they have the headroom of thex708p’s. Gotta admit that I’m a JBL fan. Had some JBL powered monitors (6328p) and never had an issue.

I've had my LSR6328s since 2006 and they have likewise never had a problem. Pro monitors are generally far more reliable than home-audio gear because it has to be. Engineers can't suddenly abort the recording session because the monitors stop working. Any company whose monitors broke down regularly would be out of business pronto.
 

Robbo99999

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Perhaps you should reread what I actually said. I stated that the height you get in playback is spurious and inaccurate but that it gives a sense of height that you get in live music but which the recording CANNOT, by its very nature, capture. My point is that sometimes inaccuracies can simulate the original sound more realistically, broadly speaking, than an ostensibly accurate reproduction.
I still think that's rubbish :D. Of course it's ok to have different opinions though.
 

T.J. McKenna

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I still think that's rubbish :D. Of course it's ok to have different opinions though.

An analogy to what I was talking about might be the way speakers with very wide horns were used in the mono era. Something like an Altec Voice of the theatre had a horn about three feet across and so the sonic image appeared quite a bit wider than the tiny mono image a much narrower speaker would have given. Undoubtedly the spread image produced by the horn would have been a less accurate reproduction of the recording but to many listeners it may have sounded more like real live music, despite its spurious inaccuracy. And Magnepan owners seem to like the sense of height the large panels give, even though there is no height information contained on the recording.
 

Robbo99999

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An analogy to what I was talking about might be the way speakers with very wide horns were used in the mono era. Something like an Altec Voice of the theatre had a horn about three feet across and so the sonic image appeared quite a bit wider than the tiny mono image a much narrower speaker would have given. Undoubtedly the spread image produced by the horn would have been a less accurate reproduction of the recording but to many listeners it may have sounded more like real live music, despite its spurious inaccuracy. And Magnepan owners seem to like the sense of height the large panels give, even though there is no height information contained on the recording.
You're talking there about wide directivity creating reflections, to me that's not the same as the word "inaccuracies" you used earlier to create "height information". I agree that speakers with good directivity and wide dispersions can increase the size & impression of the soundfield, so that it encompasses you more......but I don't agree with your earlier terminology re "inaccuracies" creating a "sense of height".......it might just be a problem of terminologies. I do certainly believe in the positive effects of speakers with good directivity and wide beam widths, as I believe that allows reflections to enhance the sound.
 

Richard Berg

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So how do microphones convey this sense of height and speakers play it back?
If you want to learn how spatial cues get encoded in (non-object-based) recording formats and interpreted by the brain, there's a whole other subforum.

Suffice to say the phenomenon is just as "real" as any other attribute of recorded music, otherwise how would your ears perceive the height of a live performance?

If you recorded sounds on the recording studio ceiling and then on the floor would playback through speakers place the sounds on or above your ceiling and on the floor? I think not.
The question doesn't make sense. Moving a microphone moves the perceptual location of the listener, not the sound source.

By this logic you only need a single microphone and speaker to reproduce stereo width; and, in fact, every aspect of spatial reproduction.
One microphone can (in theory) reproduce the entire omnidirectional sound field at a single point. I guarantee you'd notice if you move a singer's mic even slightly L/R of her mouth: the ratio of reflected sounds, their relative timing, and tonality are all affected. Importantly, they're affected in ways that our brain has already learned to recognize as "directional" through long experience living & interacting in similarly-reflective spaces.

Of course, more points is better; the optimal # of mics to reproduce a sound field is (again in theory) infinite. Our brains are adept at combining multiple inputs: from both ears simultaneously, and from small unconscious perturbations of the head over time, though we quickly reach the point of diminishing returns.

More advanced mics build on this idea by placing multiple capsules into a single enclosure at a pre-calibrated polar offset. In this sense they are strictly superior to the human ear, allowing directionality ("head tilt") to be adjusted in post. Again, all from a single point capture; it remains true that more mics offer even more creative possibility.
 

T.J. McKenna

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You're talking there about wide directivity creating reflections, to me that's not the same as the word "inaccuracies" you used earlier to create "height information". I agree that speakers with good directivity and wide dispersions can increase the size & impression of the soundfield, so that it encompasses you more......but I don't agree with your earlier terminology re "inaccuracies" creating a "sense of height".......it might just be a problem of terminologies. I do certainly believe in the positive effects of speakers with good directivity and wide beam widths, as I believe that allows reflections to enhance the sound.

What I'm saying is that there are inherent limitations to stereo recordings and that the more accurate playback the more clearly these limitations are displayed; in other words, the recording doesn't sound like the original live performance in certain respects - the lack of height being one of them. And some of these limitations may be compensated for (not necessarily intentionally) by deviations from accuracy. Height, which doesn't exist on the two-channel recording, can be simulated by reflections from floor and ceiling as well as by the size of the speaker itself. This sense of height is spurious and inaccurate but to some listeners it gives the impression, however inaccurate, of this aspect of live music better than a more accurate reproduction of the height encoded on the recording would. And a bipolar speaker often gives a greater sense of space than a forward-radiating speaker even if the latter is notionally more accurate.
 

T.J. McKenna

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If you want to learn how spatial cues get encoded in (non-object-based) recording formats and interpreted by the brain, there's a whole other subforum.

Suffice to say the phenomenon is just as "real" as any other attribute of recorded music, otherwise how would your ears perceive the height of a live performance?


The question doesn't make sense. Moving a microphone moves the perceptual location of the listener, not the sound source.


One microphone can (in theory) reproduce the entire omnidirectional sound field at a single point. I guarantee you'd notice if you move a singer's mic even slightly L/R of her mouth: the ratio of reflected sounds, their relative timing, and tonality are all affected. Importantly, they're affected in ways that our brain has already learned to recognize as "directional" through long experience living & interacting in similarly-reflective spaces.

Of course, more points is better; the optimal # of mics to reproduce a sound field is (again in theory) infinite. Our brains are adept at combining multiple inputs: from both ears simultaneously, and from small unconscious perturbations of the head over time, though we quickly reach the point of diminishing returns.

More advanced mics build on this idea by placing multiple capsules into a single enclosure at a pre-calibrated polar offset. In this sense they are strictly superior to the human ear, allowing directionality ("head tilt") to be adjusted in post. Again, all from a single point capture; it remains true that more mics offer even more creative possibility.

Yes, moving the microphone will change our perception of the sound but it still doesn't in itself capture all the spatial clues. For that you require additional microphones. If you want to record and replay an accurate reproduction of height you would need two microphones in vertical orientation and two loudspeakers also in vertical orientation. That way you could reproduce differences in height but if you combine that with the need to reproduce width as well you're starting to get into very complicated territory. And height isn't a high priority, as it happens. Most voices and instruments are at roughly the same height and very few musical works make any use of height at all. Perhaps something like Britten's "Noyes Fludde" might have the Voice Of God emanating from the ceiling but overall it's not something most composers have agonized over.
 
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