To me the issue is this: for high output performance where high SPL dictates the use of several drivers a synergy is going to work better. But for normal HT SPL levels, the simplicity of a 2-way is going to work better. It's a matter of the application, not that one is superior to another in all cases.
Is this right? Shouldn't an MTM be free from crossover notches because the acoustic center is the same for both the HP and LP?
If I were to do MTM, I'd place them sideways to narrow the polar DI to allow for a higher DI waveguide. I care less about vertical directivity than I do horizontal (being as I deal with floor and ceiling bounce in the room and not in the loudspeaker system.)
Hi Earl,
I think we talk about different things: in the quote you made i was talking about the nature of floor/ceiling reflection ( bounce).
With mtm there is two different signal path ( vertical) and so there is chance than rather than one big ( low q) suckout ( notch) there is two narrower one happening.
And as we are less sensitive to high Q notch then in my view it can make sense to use this to mitigate the floor/ceiling bounce.
I don't know about mtm sideway. I was not thrilled by 'the crude approach' of (eg) the Kinoshita's RM-4 layout with boomers side by side: too narrow directivity for my preferences. Maybe it wasn't from the boomer's arrangement alone, maybe the junction with horns, maybe diffraction from soffit mounting... i don't know.
That said i think i've heard the same issue ( but offseted in freq) with a 2x6,5" +1" dome using inspired layout experiment i made some years ago.
I think we talk about different things: in the quote you made i was talking about the nature of floor/ceiling reflection ( bounce).
With mtm there is two different signal path ( vertical) and so there is chance than rather than one big ( low q) suckout ( notch) there is two narrower one happening.
And as we are less sensitive to high Q notch then in my view it can make sense to use this to mitigate the floor/ceiling bounce.
I don't know about mtm sideway. I was not thrilled by 'the crude approach' of (eg) the Kinoshita's RM-4 layout with boomers side by side: too narrow directivity for my preferences. Maybe it wasn't from the boomer's arrangement alone, maybe the junction with horns, maybe diffraction from soffit mounting... i don't know.
That said i think i've heard the same issue ( but offseted in freq) with a 2x6,5" +1" dome using inspired layout experiment i made some years ago.
I think this is a stretch of what I actually said; "yet more proof that centralization of the sound sources are desirable even beyond the capabilities of a 2way."
What I mean by this is that, There is a desire, to centralize the sound source, beyond the capabilities of a 2way. Centralization of the sources, does not automatically make the loudspeaker superior. At the large 2way level, we are to a point where if you make a change, for the better, it comes with consequence. Moving towards a Synergy, is a step left or the right, not exactly forward...also, any great design deferring from a 2 way seems to be the same. The WAW/FAST design being, to me, at least, a stand out, of the 2 way layout, usually at the sacrifice of having to use a Coaxial dynamic driver for the wide band top driver
There are plenty of people who favor full range point source coverage over a 2 way. I hold @mark100 experience with his newly formed 18" woofer wielding synergy, in high regards. @planet10, another lover of Fullrange drivers. On paper, a full range, point source driver, is the pinnacle of loudspeaker design isn't it?
My point is that there are gains and loss, by using the full range approach, and there is loss and gain by using the 2 way approach. What is gained in the full range approach, is evidence, of the flaws, of a 2 way.
But why??
People hear the word "point" and imagine it meaning that we focus on a point... but does that even matter? How do they justify this imaginary construct? Why is a point source that important?
Well, there ar other properties of an ideal point source, eg: consistent DI. It's difficult enough to get this right when drivers are separated that you'd have to imagine it's often done wrong. Add that to the fact that it can be near to impossible to diagnose certain things by ear alone, so there may be some guessing going on. We know DI is an important factor.
-Maybe it's time for the term 'point source' to stop being incorrectly used to describe coincident drivers, and be replaced with the things that matter.
Hi, I think that's making an issue with SPL, where one doesn't exist.
Yes, Synergies can rather uniquely accomplish huge SPL by combining multiple drivers in a common box, but that's just a side benefit of the fundamental design.
The fundamental design imo, being the ability to mount multiple bandwidths onto a common constant-directivity horn.
If you want loud, then use multiple drivers per band.....but there's no real need to do so otherwise
As an example of not really being about SPL...take a 2-way CD over 15", and compare to say the Danley SH-50.
Both have a CD reaching down to the same zipcode....so there's no SPL advantage there.
The two-way has a 15"; the SH-50 has two 12"s. Slight advantage to the SH-50 based solely on Sd, but not one you'd list as a jump in SPL.
The SH-50 has four 5" mids......does that make for an overall SPL advantage?
I don't see how....linear SPL is limited by the lowest SPL band.....highs and lows are equal, or dang near equal.
So, no real SPL advantage to the mids.
So the mids in the SH-50, and Synergies in general, are all about SQ.... ime.
getting multiple bands to act together as a point source.....again, on a common horn.
After SQ, how loud you want is the next design criteria (just like with 2-ways
Also, it's worth mentioning the number of small synergies that are around, like Danleys Studio series, and DIY efforts we've seen. Certainly not SPL monsters.
One thing i can wholeheartedly agree with is; if better means easier and simpler to properly implement, a 2-way wins!
But if better is about potential SQ, from my experience a 2-way leaves some on the table...
The problem that I have, is that I have yet to see a polar map for a synergy that is as good as a great 2 -way. If there are some then please post them. Pleas no highly averaged stuff.
Here's the kind of polars i get....although I can only provide horizontal until i get to try out my new 5 mics on an outdoor vertical mast rig.
(The way i make the syn boxes doesn't allow for setting the on their sides the make spinorama meas).
Anyway, here's the last set i made outdoors of a 75x60 degree box. 0-30 deg, steps on 10.
And here's a 90x60 box I'm currently using in a LCR config, made indoors close, no gating. Zero to 20 degree, steps of 10.
I don't bother with polars outside the conical wall angles anymore.
And have come to believe consistency within listening window angle is what dominates SQ.
(All my syns are made to cross to a sub at 100Hz.)
Anyway, these are giving me a sound I love
(The way i make the syn boxes doesn't allow for setting the on their sides the make spinorama meas).
Anyway, here's the last set i made outdoors of a 75x60 degree box. 0-30 deg, steps on 10.
And here's a 90x60 box I'm currently using in a LCR config, made indoors close, no gating. Zero to 20 degree, steps of 10.
I don't bother with polars outside the conical wall angles anymore.
And have come to believe consistency within listening window angle is what dominates SQ.
(All my syns are made to cross to a sub at 100Hz.)
Anyway, these are giving me a sound I love
Yeah, that's part of why i moved on to latest syn 10 version. I just wanted to show a set made outdoors, and not the indoor crap folks commonly post (like i did in second syn10 plot)
But frankly, even the problem at 3k in the outdoor set, isn't as important to me as the coherency in overall traces, going all the way down.
Imo, music lives in the midrange, and we pay way too much attention to the idea of where the ear is the most sensitive.
But frankly, even the problem at 3k in the outdoor set, isn't as important to me as the coherency in overall traces, going all the way down.
Imo, music lives in the midrange, and we pay way too much attention to the idea of where the ear is the most sensitive.
Yep, we do seem to have different preferences and opinions, but hey, that's all good and well, right?
By coherence, I meant the coherence as measured in the transfers i posted. It's the top red trace in the magnitude pane. Sorry if that passed by.
If you'll look at the first outdoor set, the one with the crap at around 3kHz, you can see coherence is 100% across the measurement.
That tells me that the measurement's overall flatness mag and phase is very valid. No gated smoothing, no reflections, etc.
Tells me the warts are real too, and need work.
The second indoor trace also ungated, has decent coherence too.
But it's an up close measurement, within the near field (acoustic definition), and therefore pretty suspect imo.
By coherence, I meant the coherence as measured in the transfers i posted. It's the top red trace in the magnitude pane. Sorry if that passed by.
If you'll look at the first outdoor set, the one with the crap at around 3kHz, you can see coherence is 100% across the measurement.
That tells me that the measurement's overall flatness mag and phase is very valid. No gated smoothing, no reflections, etc.
Tells me the warts are real too, and need work.
The second indoor trace also ungated, has decent coherence too.
But it's an up close measurement, within the near field (acoustic definition), and therefore pretty suspect imo.
Good discussion guys, my post is little off the rails of what you are talking about, personally I need to understand the technical definition of Coherency as it applies to engineering as Gedlee points out. I would assume the word can be used subjectively which is a trait of perception.
This brings me to another point. The vertical axis is completely left out of the picture. Where is 0 on the vertical axis, outside of the psychoacoustical cue of the HF? Where ever I place the horn on the vertical axis, is never inherently wrong because there is no type of vertical distinction to begin with.
Depending on height of all drivers, the image and reverb characteristics change. There is, in my opinion, a trend of expectation of bass to come from
below. A lot of the acoustical instruments follow along this theme (not just the average loudspeaker system), obviously not all, but the very popular, drumset's, bass drum, lives on the floor (bass guitar bass bins, acoustic bass resonator hole, etc). Combine that with a midrange living in the middle area, supporting a snare in the same physical space on a typical drumset...cymbals usually live physically, above the toms, snare and bass drum.... having a tweeter on top, helps to create a physical arrangement that supports a realistic vertical image of a drumset.... lots and lots of music with the bass drum, snare, cymbals as the backbone of the rhythm section. Flutes are held up to mouth while sax and French horn radiate from the mid level...The point I'm trying to make is that there is some musicality to TMW or TM.
This stands out to me in this moment because of how congregated the presentation became after going from a 53" high tweeter/mid to 36"s high tweeter... It almost sounded incorrect when I first switched. I then recalled that stereo is flawed, vertically, no matter what, even as a point source, it only seeks to convey information regarding the horizontally axis. Still, psychologically I (we?) have a degree of expectation for bass to be common to the lower area... I think there may be a connection to the coupling that low bass has with the borders around the sound event and our expectation of bass to be reinforced or more prevalent from the a lower point, the lower border is always there.
Interesting at least, I think that covering the whole vocal range from the same axis as the HF is a sort of, best compromise. It is neither wrong nor correct, it seems to be the least distracting to me. I think some of this has to do with the physical distance between drivers and the close proximity I listen at. Its not like I have an issue with my 1"+4" 2 way but the physical space they take up allows very close proximity, likely mitigating the issue.
I think there is relevance to pressure vs frequency as opposed to the pitch of the head, during listening.... The highly regarded ESL that makes it to the top of a lot of list as, one of the best sources listened to, seems to follow along with what I could desirable regarding this topic of image and perception. No matter how you Pitch your Head, while listening to a large ESL, pressure of all frequency, potentially, will be coming from that area of the panel, with only directivity (and room modes) to dictate what actually makes it to your ear. Somehow, this matters.
The physical manifest in dynamic and waveguided speaks is a system that cover's maximum bandwidth from every driver using least amount of drivers or the least amount spacing horizontally or vertically. I think a large 2way is the answer. My idea of "2way" includes anything that can cover "everything" from 2 points, like a synergy on top of sub.......
This is what I've been listening to at about 45", one channel. I thought the HF would be cleaner due to the narrow polar but its a lot cleaner than say a dome tweeter would have been in the same situation. I am impressed with my ears over the last 2 days as I experimented with the 2way config. Through only the use of reference tracks I diagnosed miss set, parameters in my XO. Accidently setting a LR48db LP to Butterworth, out of phase, and before all of that, a HP on the horn set 65hz? I'm impressed with myself that I could hear it, simply because, looking at the FR and phase, nothing was out of place, per say. As soon as I switched the filter type, the material hidden in the XO, came forth. I was considering that the mechanical HP of the slot did something un repairable and that I would have to take the woofers out of the slot....it was a miss set filter type....WTF
This brings me to another point. The vertical axis is completely left out of the picture. Where is 0 on the vertical axis, outside of the psychoacoustical cue of the HF? Where ever I place the horn on the vertical axis, is never inherently wrong because there is no type of vertical distinction to begin with.
Depending on height of all drivers, the image and reverb characteristics change. There is, in my opinion, a trend of expectation of bass to come from
below. A lot of the acoustical instruments follow along this theme (not just the average loudspeaker system), obviously not all, but the very popular, drumset's, bass drum, lives on the floor (bass guitar bass bins, acoustic bass resonator hole, etc). Combine that with a midrange living in the middle area, supporting a snare in the same physical space on a typical drumset...cymbals usually live physically, above the toms, snare and bass drum.... having a tweeter on top, helps to create a physical arrangement that supports a realistic vertical image of a drumset.... lots and lots of music with the bass drum, snare, cymbals as the backbone of the rhythm section. Flutes are held up to mouth while sax and French horn radiate from the mid level...The point I'm trying to make is that there is some musicality to TMW or TM.
This stands out to me in this moment because of how congregated the presentation became after going from a 53" high tweeter/mid to 36"s high tweeter... It almost sounded incorrect when I first switched. I then recalled that stereo is flawed, vertically, no matter what, even as a point source, it only seeks to convey information regarding the horizontally axis. Still, psychologically I (we?) have a degree of expectation for bass to be common to the lower area... I think there may be a connection to the coupling that low bass has with the borders around the sound event and our expectation of bass to be reinforced or more prevalent from the a lower point, the lower border is always there.
Interesting at least, I think that covering the whole vocal range from the same axis as the HF is a sort of, best compromise. It is neither wrong nor correct, it seems to be the least distracting to me. I think some of this has to do with the physical distance between drivers and the close proximity I listen at. Its not like I have an issue with my 1"+4" 2 way but the physical space they take up allows very close proximity, likely mitigating the issue.
I think there is relevance to pressure vs frequency as opposed to the pitch of the head, during listening.... The highly regarded ESL that makes it to the top of a lot of list as, one of the best sources listened to, seems to follow along with what I could desirable regarding this topic of image and perception. No matter how you Pitch your Head, while listening to a large ESL, pressure of all frequency, potentially, will be coming from that area of the panel, with only directivity (and room modes) to dictate what actually makes it to your ear. Somehow, this matters.
The physical manifest in dynamic and waveguided speaks is a system that cover's maximum bandwidth from every driver using least amount of drivers or the least amount spacing horizontally or vertically. I think a large 2way is the answer. My idea of "2way" includes anything that can cover "everything" from 2 points, like a synergy on top of sub.......
This is what I've been listening to at about 45", one channel. I thought the HF would be cleaner due to the narrow polar but its a lot cleaner than say a dome tweeter would have been in the same situation. I am impressed with my ears over the last 2 days as I experimented with the 2way config. Through only the use of reference tracks I diagnosed miss set, parameters in my XO. Accidently setting a LR48db LP to Butterworth, out of phase, and before all of that, a HP on the horn set 65hz? I'm impressed with myself that I could hear it, simply because, looking at the FR and phase, nothing was out of place, per say. As soon as I switched the filter type, the material hidden in the XO, came forth. I was considering that the mechanical HP of the slot did something un repairable and that I would have to take the woofers out of the slot....it was a miss set filter type....WTF
As a subjective term, I have no idea what it would mean.
Technically it is the cross product of the input signal and the output signal normalized (divided) by the square of the input magnitude.
Simple put the coherence shows how much of the output of the system under test is linearly related to the input. A value of one indicates that all of the output is linearly related to the input, in other words there is no nonlinearity and no extraneous noise in the measurement. A value of 1.0 means a very clean measurement of a dominantly linear system. Good measurements should always have a value very near 1.0.
I agree. It's really a preference thing and i think the room's ER plays a role too. I prefer a little bit over my head but not too high, maybe 30cm.
Except that a loudspeaker is different than an instrument. And we ask them to do some very different thing.
I see how seductive it is to find coincidence in how you perceive and create a mental image of what you see but it's a shortcut.
You already tracked real instruments Camplo? Yes so you know the 'best' location of mics are sometimes a bit weird if we could judge with our eyes only.
Eg: last time i tracked a double bass the main mic ( U87) was located inside the bridge, kept here with foam as suspension.
I think in one of his interview Dunlavy clearly stated the difference and the choice he made for his loudspeakers.
And depth. But like you i never experienced any 3d with height axis movements on acoustic recording other than binaural. I had feelings of movement in this height axis on some electronic music with synthesizer filters opening though.
It's a good sign to me you are able to identify by hear some issues you thoughts you wouldn't.
You cross around 250hz? How does the ppsl sound at this freq?
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HRTF affects, if your speaker is higher than head it sounds brighter. Head, shoulders, pinna all have different coloration to sound from various elevation. Thinking back in time I've always leaned forward and watching the floor when critically listening, for some reason, and its probably at least two reasons, more balance of direct and reverberant sound and additional bightbess from HRTF. Play white noise video from Youtube with your mobile and lift it up and down in front of your face, quickly above eye level sound gets brighter, and below gets duller.
If I remember correctly, brain tends to think sound comes above if it cannot localize it properly, kind of dumpster bin where unknown goes. Thus stereo phantom center gets some elevation for highs naturally.
Besides lifting soeaers also tilting might affect perceived elevation, as floor and ceiling early reflections change some.
Fortunately its not too hard to experiment with speaker elevation so evetyone can test what works and what doesn't. Untreated livingroom might benefit lowering speakers, from between naked parallel walls to between furnishing, flutter echo is bad.
If I remember correctly, brain tends to think sound comes above if it cannot localize it properly, kind of dumpster bin where unknown goes. Thus stereo phantom center gets some elevation for highs naturally.
Besides lifting soeaers also tilting might affect perceived elevation, as floor and ceiling early reflections change some.
Fortunately its not too hard to experiment with speaker elevation so evetyone can test what works and what doesn't. Untreated livingroom might benefit lowering speakers, from between naked parallel walls to between furnishing, flutter echo is bad.