"So to keep the polarity same, would the tweeter need to be set back further?"
Almost, but not really. 2nd order L-R xo needs that reversed polarity setup. Of course you can align the drivers to get good phase match at the xo point with identical polarity, but then phase tracking above and below the xo point would suffer greatly, causing dips and peaks in the frequency response.
Almost, but not really. 2nd order L-R xo needs that reversed polarity setup. Of course you can align the drivers to get good phase match at the xo point with identical polarity, but then phase tracking above and below the xo point would suffer greatly, causing dips and peaks in the frequency response.
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I don't think so that a LR2 crossover speaker can reproduce a squarewave, because it have phase-rotation and timing difference. It's true that the aligned drivers with symmetrical LR2 slopes have the same phase rotation so they are in-phase at all frequencies but the driver with the low-pass (woofer) have a half period delay compared to the driver with the high-pass (tweeter).
With LR4 the delay is 1 period, with LR6 it's 1.5 period, with LR8 it's 2 period and so on.
But you listening to squarewaves and you ears can identify that?
With LR4 the delay is 1 period, with LR6 it's 1.5 period, with LR8 it's 2 period and so on.
But you listening to squarewaves and you ears can identify that?
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One could argue that a squarewave is slightly more complex than a sinusoidal and music is much more complex than a square wave. So how should a speaker which is only capable of accurately reproducing sinusoidals be able to accuratley reproduce music ?
O.K.
In real life it is much more subtle of course and it is difficult to determine which timing errors would be below perception for every possible situation (source-material, listener, listening environment).
Regards
Charles
Yeah and it is hard to evaluate "one thing" since when one thing is changed, multiple things change. For example if one changes delay of a driver, or crossover slope, the polar response will change as well. Now you don't know what the new (subjectively better or worse in room response) sound is to thank for was it the phase response, the crossover slopes or the polar response? If not using DSP the listening axis frequency response won't be the same either. Power response will change even with DSP in use. So, one has to compare the old and the new side by side to be able to say which one is better or call a tie. Have fun!
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Oh maybe close enough, you are right. Electronic parts are not ideal so it is easy to divert from the simulated perfect model in real world, especially if not great care is taken. A 0.5db change is audible and might contribute to the perceived difference. With DSP one can choose ideal curve and eq to that every time more accurately (on one axis).
To me, it's stretching the definition for Jeff to even call this a 'quasi' transient perfect design. His own measured response (with the microphone fine-tuned to the most optimal point) shows a nearly 180 degree phase rotation across the band.
Nothing about that kit is linear-phase, in my opinion.
For the OP: If you're interested in a smallish speaker for near-field usage that might get you close to "linear-phase" production, I suggest maybe a coaxial driver setup with something close to a first-order crossover.
Dave.
Nothing about that kit is linear-phase, in my opinion.
For the OP: If you're interested in a smallish speaker for near-field usage that might get you close to "linear-phase" production, I suggest maybe a coaxial driver setup with something close to a first-order crossover.
Dave.
Thanks to all participants here. Trying to wrap my head around the phase
This discussion of phase response has opened a can of worms for me. That is great, I can get a better understanding.
Of course I am not listening to square waves but I am trying to learn the correlation of proper timing between drivers and how to look for it in the measurements. Let's say we are still talking about a typical 2-way monitor.
1. Can someone tell me what to look for in the measurements to identify if a speaker can be at least close to being able to produce a good square wave? My guess is that to play a square wave, the phase has to be a flat line, with NO tilt.
Yes? Or is this an oversimplification and phase does NOT have to be a flat line?
2. So if the phase response is a TILTED continuous line, like the measurements of the "Revelation Two - M4 WG", what does this say about its ability to play a square wave?
3. What does the phase tracking tell us? Let's say I want the woofer and tweeter to start and stop in sync. This is how I understand the proper square wave reproduction. The phase tracking doesn't really tell about that?
To understand, I must ask, does the "phase response" tell us BOTH: When both drivers START reproducing sound and STOP reproducing sound? And what's inbetween..
This discussion of phase response has opened a can of worms for me. That is great, I can get a better understanding.
Of course I am not listening to square waves but I am trying to learn the correlation of proper timing between drivers and how to look for it in the measurements. Let's say we are still talking about a typical 2-way monitor.
1. Can someone tell me what to look for in the measurements to identify if a speaker can be at least close to being able to produce a good square wave? My guess is that to play a square wave, the phase has to be a flat line, with NO tilt.
Yes? Or is this an oversimplification and phase does NOT have to be a flat line?
2. So if the phase response is a TILTED continuous line, like the measurements of the "Revelation Two - M4 WG", what does this say about its ability to play a square wave?
3. What does the phase tracking tell us? Let's say I want the woofer and tweeter to start and stop in sync. This is how I understand the proper square wave reproduction. The phase tracking doesn't really tell about that?
To understand, I must ask, does the "phase response" tell us BOTH: When both drivers START reproducing sound and STOP reproducing sound? And what's inbetween..
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Phase is actually a frequency dependent timing difference, so you need flat phase response to reproduce a square wave, no tilt or wrap are allowed. Easiest way to achieve this is to use DSP. The Kii three speaker is close to that goal with the Exact setting I think. Check the phase- and time-corrected 3-way LR4 step response Fig. 1. vs the traditional LR4 Fig. 2.:
Kii Audio Three loudspeaker Measurements | Stereophile.com
Kii Audio Three loudspeaker Measurements | Stereophile.com
As I understand, for a PASSIVE filter:
The closest to flat phase would be the only 1st order crossover monitor design I have found by Troels Gravesen:
MW19P-8
it's open source design so can be easily built. What do you guys think of this design? I am thinking it's a good option.
Let's say I will not buy a DSP speaker and want to keep all analogue. If I use a 2-way monitor with a tilt in the phase (as seen even in the best designs that were mentioned earlier) can I use an active line level filter to flatten out the phase?
Like an active crossover, except it's a phase only compensation (inserted prior to the amplifier)...
The closest to flat phase would be the only 1st order crossover monitor design I have found by Troels Gravesen:
MW19P-8
it's open source design so can be easily built. What do you guys think of this design? I am thinking it's a good option.
Let's say I will not buy a DSP speaker and want to keep all analogue. If I use a 2-way monitor with a tilt in the phase (as seen even in the best designs that were mentioned earlier) can I use an active line level filter to flatten out the phase?
Like an active crossover, except it's a phase only compensation (inserted prior to the amplifier)...
Yes, you can. You could even do it all passive with this kind of filter - Lattice phase equaliser - Wikipedia
That Troels speaker you linked to is a 4th-order design, not 1st-order. It's not even close to being linear phase.
You appear to have an objective here, but I'm not sure what it is.
I'm not sure you're appreciating how high the bar is for a speaker system to create a linear-phase response. VERY few speakers are capable of this, and then only when measured at a single point in space.
If you want a set of speakers for near-field listening that are linear phase, I suggest headphones.
Dave.
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Agree with Davey that a linear-phase design is neither easy nor commonplace (note that implementing linear phase can introduce other headaches).
But as a quick solution, Quad's ESL-63 (and its derivatives) are coaxial, linear phase, and can be purchased second-hand.
Quad ESL-63 loudspeaker Measurements | Stereophile.com
But as a quick solution, Quad's ESL-63 (and its derivatives) are coaxial, linear phase, and can be purchased second-hand.
Quad ESL-63 loudspeaker Measurements | Stereophile.com
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