Time aligning...
kharp1
Posts: 3,453
Not sure this is the right place to post, so, if not please forgive me.
Do bookshelf monitors need to be time aligned? I've read conflicting information. Some say 2 way designs do not require time aligning. Some say they can still benefit from it. Is there a hard and fast rule to this? From my experience in the audio world the answer to that question is probably "no." Does it depend on the crossover design being used?
Do bookshelf monitors need to be time aligned? I've read conflicting information. Some say 2 way designs do not require time aligning. Some say they can still benefit from it. Is there a hard and fast rule to this? From my experience in the audio world the answer to that question is probably "no." Does it depend on the crossover design being used?
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In a properly designed speaker,the relative phase differences caused by the physical offset between the acoustic centers of the tweeter and mid woofer(roughly the location of the voicecoils)will have been compensated for in the crossover design.
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I was referring to the typical 2 way with a flat baffle.The design axis(best measured response) is usually at the tweeter level or midway between the two drivers. Ofcourse Wilson and others use physical offset to achieve time alignment.Speakers like Vandersteens that use very shallow sloped first order crossovers are very sensitive to driver offset so benefit greatly from stepped baffles.The steeper the roll off rate of the crossover the less sensitive they are to driver offset.
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I would not use Wilson as an example of time aligned. Technically they are not.In a properly designed speaker,the relative phase differences caused by the physical offset between the acoustic centers of the tweeter and mid woofer(roughly the location of the voicecoils)will have been compensated for in the crossover design.
At what height though? There is a reason Wilson makes the speakers the way they do with rails to properly align each driver. I know the cheaper offerings don't have that feature but it is utilized.In a properly designed speaker,the relative phase differences caused by the physical offset between the acoustic centers of the tweeter and mid woofer(roughly the location of the voicecoils)will have been compensated for in the crossover design.
At what height though? There is a reason Wilson makes the speakers the way they do with rails to properly align each driver. I know the cheaper offerings don't have that feature but it is utilized.Magico M2, JL113v2x2, EMM, ARC Ref 10 Line, ARC Ref 10 Phono, VPIx2, Lyra Etna, Airtight Opus1, Boulder, AQ Wel&Wild, SRA Scuttle Rack, BlueSound+LPS, Thorens 124DD+124SPU, Sennheiser, Metaxas R2R -
I love how folks on this forum have tons of great info to offer, and offer it so willingly. I have played around a little with height adjustment, but, while searching out sound treatments I noticed some monitor isolation with 4deg angle. Started me to wondering, which led to an nternet search, which left me with more questions.
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I would not use Wilson as an example of time aligned. Technically they are not.True .Sloping or stepping the baffle to add delay to the tweeter aids in the crossover design but does not make it a true time coherent minimum phase speaker.To achieve that requires a true first order crossover and very few very few commercial that can actually be considered as such,Vandersteen older Theils and a couple of others.Mr Vandersteen would disagree but it a matter of debate as to the real sonic benefits of having true minimum phase response.
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I would not use Wilson as an example of time aligned. Technically they are not.True .Sloping or stepping the baffle to add delay to the tweeter aids in the crossover design but does not make it a true time coherent minimum phase speaker.To achieve that requires a true first order crossover and very few very few commercial that can actually be considered as such,Vandersteen older Theils and a couple of others.Mr Vandersteen would disagree but it a matter of debate as to the real sonic benefits of having true minimum phase response.
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True .Sloping or stepping the baffle to add delay to the tweeter aids in the crossover design but does not make it a time coherent minimum phase speaker.To achieve that requires a true first order crossover and there are very few commercial designs that can actually be considered as such,Vandersteen older Theils and a couple of others.Mr Vandersteen would disagree but it is a matter of debate as to the real sonic benefits of having true minimum phase response.I would not use Wilson as an example of time aligned. Technically they are not.
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Fred's into the homemade hootch again....
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Let me expand on my post.
There are two ways that a speaker is time coherent:
1. Timely propogation of leading edge of sound via physical location of drivers relative to seating distance.
(That's what Wilson does to great effect.)
2. Time delays eliminated via use of the proper cross overs, typically lower order introduce less time delays.
(Which Wilson does not subscribe to, hence they cannot be truly time coherent).
The problem though with subscribing to this whole "everything needs to be time aligned" mantra is that in the end, it only works if the speaker is pointed and toed in directly to the ear... Which most of us don't even do.... And I'm not sure that our ears are unable to tolerate the slightest variations of time coherence... I bet we can hence a lot of speakers still sound good.Magico M2, JL113v2x2, EMM, ARC Ref 10 Line, ARC Ref 10 Phono, VPIx2, Lyra Etna, Airtight Opus1, Boulder, AQ Wel&Wild, SRA Scuttle Rack, BlueSound+LPS, Thorens 124DD+124SPU, Sennheiser, Metaxas R2R -
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Yes tons of designs use simple 6db electrical crossovers but the actual resulting acoustical slope is not a "true" first order.Usually the drivers natural rolloffs are incorporated as part of the crossover slope so the resulting rolloff is more like 12-18db not 6,so not minimum phase.Vandersteen ,Theil,Dunlavy are the few I can think of that can actually reproduce a square wave.Ofcourse now with DSP ,it will be possible to correct not only for frequency response but also phase issues. -
Yes tons of designs use simple 6db electrical crossovers but the actual resulting acoustical slope is not a "true" first order.Usually the drivers natural rolloffs are incorporated as part of the crossover slope so the resulting rolloff is more like 12-18db not 6.Vandersteen ,Theil,Dunlavy are the few I can think of that can actually reproduce a square wave.Ofcourse now with DSP ,it will be possible to correct not only for frequency response but also phase issues.
Interesting...I have to assume that DSP, like many other electronic correction methods, has it's own set of drawbacks. Would I be correct in that assumption? -
You are correct.The particular analog-digital and digital -analog conversion IC's,firmware, analog output stages,power supply etc. will all add their own flavour to the mix.
Interesting...I have to assume that DSP, like many other electronic correction methods, has it's own set of drawbacks. Would I be correct in that assumption? -
That's why most things in audio are not written in stone. All depends too how sensitive you are to time alignment, especially in smaller speakers. Requires one to experiment a bit themselves in their own room.
Aside from crossovers and design alterations, I've seen people tilt speaker back, even tilt forward too, lay them on their sides even. No hard and fast rules.HT SYSTEM-
Sony 850c 4k
Pioneer elite vhx 21
Sony 4k BRP
SVS SB-2000
Polk Sig. 20's
Polk FX500 surrounds
Cables-
Acoustic zen Satori speaker cables
Acoustic zen Matrix 2 IC's
Wireworld eclipse 7 ic's
Audio metallurgy ga-o digital cable
Kitchen
Sonos zp90
Grant Fidelity tube dac
B&k 1420
lsi 9's -
That's why most things in audio are not written in stone. All depends too how sensitive you are to time alignment, especially in smaller speakers. Requires one to experiment a bit themselves in their own room.
Aside from crossovers and design alterations, I've seen people tilt speaker back, even tilt forward too, lay them on their sides even. No hard and fast rules.
My current setup
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^^^^ Haha! Nice! On the time alignment issue, I'm a bit confused. I seems you would have to have pitch perfect, golden ears to hear such things...just my 2 nickels. Many of ya's know I'm a diehard 'stat man. I want to hear the soundstage bounced off the back wall, and recreated with the frontal energy
Is this about high Q's arrive at your ears (pinnea's) faster than the low's? Does that for a more accurate sound?
Thorens TD125MKII, SME3009,Shure V15/ Teac V-8000S, Denon DN-790R cass, Teac 3340 RtR decks, Onix CD2...Sumo Electra Plus pre>SAE A1001 amp>Martin Logan Summit's -
I had to find this pic for ya! A pair of ML Prodigy's in a small trailer somewhere in the southern US...
Thorens TD125MKII, SME3009,Shure V15/ Teac V-8000S, Denon DN-790R cass, Teac 3340 RtR decks, Onix CD2...Sumo Electra Plus pre>SAE A1001 amp>Martin Logan Summit's -
You can dive into time alignment and spend weeks there getting your learn on but truth be told....none of us listen in a perfect environment. The whole idea really is for speaker makers to make sure those sounds from all the drivers come out of the speaker in a time aligned fashion. However, once that sound leaves the speaker you have the room to contend with, sound absorption, your listening position, reflection points etc.
My advice is to leave the time alignment concerns to the people who make the speakers and you worry about the room treatments. Unless your OCD on this kind of stuff. Experiment a bit with the stuff you have and within your listening environment. Audio is suppose to be pleasurable, not something to needlessly worry about every aspect over. That may be a very "un-audiophile" statement, but bears some truth to it.HT SYSTEM-
Sony 850c 4k
Pioneer elite vhx 21
Sony 4k BRP
SVS SB-2000
Polk Sig. 20's
Polk FX500 surrounds
Cables-
Acoustic zen Satori speaker cables
Acoustic zen Matrix 2 IC's
Wireworld eclipse 7 ic's
Audio metallurgy ga-o digital cable
Kitchen
Sonos zp90
Grant Fidelity tube dac
B&k 1420
lsi 9's -
My knowledge is rudimentary at best, however, if as a builder/designer you're striving to build a "perfect" speaker, where every signal hits your ears as it should, it seems to me that the argument of toe in shouldn't come in to play. The speakers should be aligned whether they're toed in or not. I realize that the toe in issue will affect the sound depending on room dimensions among other things, but, even if you're toeing in to minimize early reflection shouldn't the signal coming off the driver be aligned as perfectly as possible before early reflection even comes in to play? I realize there are numerous theories, some backed by measurements, but, if the speaker is angled to adjust for time alignment wouldn't that tend to make your reflection/diffraction more exaggerated?
