phase/time alignment
- Thread starter rblnr
- Start date
Hi Steve,
The OMA New Yorker horn speakers have all of the speaker cone magnets aligned for phase and time alignment. Their testing confirmed the phase and time alignment. I think what is being referred to as phase is the wave front coming from the drivers are aligned and in phase with each other.
Rich
The OMA New Yorker horn speakers have all of the speaker cone magnets aligned for phase and time alignment. Their testing confirmed the phase and time alignment. I think what is being referred to as phase is the wave front coming from the drivers are aligned and in phase with each other.
Rich
Steve williams
Site Founder, Site Owner, Administrator
Rich i know exactly what phase alignment is. My point is i cant understand why people are thumping their chests and saying " my speaker is phase and time aligned" when I am asking " shouldnt every speaker be"
Hi Steve,
I do not argue with you that they should be aligned, but I believe that many of them are not. I believe that some manufacturers have made more effort in this area than others.
I believe that many speakers as an example have the front of the cones in the speaker cabinet all in the same plane, but the speaker magnets and rear of the cones are not aligned. That was part of the goal of Dahlquist in the original DQ-10 design. Since that time, as I recall, other methods have been developed to deal with the issue, but I do not know which manufacturers that have made such efforts.
Rich
Steve williams
Site Founder, Site Owner, Administrator
Drivers all in the same plane accounts for time alignment but are you suggesting many speaker's drivers are out of phase
When you attain one thing in speaker design you sacrifice another. For instance, if you're using first-order crossovers to attain time alignment, you give up power handling because of the shallow slopes and wider operating bands.
You also bring into prominence the driver break-up modes which now aren't supressed by the crossover.
You also can have off-axis issues because those bigger drivers are now playing further into the treble.
You can also only attain time alignment at one point in space.
Most designers don't feel the benefits outweigh the negatives.
Steve, phase shift introduced by the crossover has to be accounted for. Drivers in the same plane doesn't even close to equal time alignment.
Steve williams
Site Founder, Site Owner, Administrator
So Jeff if I understand you, you are saying that if a speaker is phase aligned it isnt time aligned and vice versa?
Steve, My Dunlavy's are time coherent. The sweet spot is very tight but the imaging is impressive. You're welcome to come over and hear them. John
Steve williams
Site Founder, Site Owner, Administrator
Jeff here is another question that I need a point of clarification. In speakers such as yours where there is a sub firing at 90 degrees to the other drivers and the sub driver resides 4-5 inches behind the other drivers how does the manufacturer correct for time and phase. To me this is an inherent problem. What am i missing?
Yes speakers can be phase coherent and not time aligned. A time-aligned speaker will be phase coherent by definition.
Steve williams
Site Founder, Site Owner, Administrator
I understand that completely but kindly answer my last question. Unless there is digital correction how can a driver firing at 90 to the other drivers and residing welll behind the other drivers be time and phase coherent?
Steve, as I said, they aren't time aligned, or as you state, time coherent. They are phase coherent which has to do with the crossover not shifitng relative phase between drivers. All the driver spacing and math is correct, and, for instance, the drivers sum nicely. I saw a measurement where Payor reversed the leads of one driver and measured the output of the two drivers at the crossover frequency: There was 41dB of suckout. Put the leads back and you have perfectly flat response. The point is that the drivers are summing correctly and the symetrical crossovers are producing phase-coherent output.
Steve, how does your system correct for time/phase issues between your Wilson mains and Gotham subs? Answer: It doesn't.
This is where DSP-based RC (Audyssey, TacT et al) can be really beneficial. Based on room measurements at the listening position(s), the DSP adds delays which correct timing/phase issues resulting from different speaker distances. The difference can be startling.
This is where DSP-based RC (Audyssey, TacT et al) can be really beneficial. Based on room measurements at the listening position(s), the DSP adds delays which correct timing/phase issues resulting from different speaker distances. The difference can be startling.
Putting it better than I ever could, the late Jim Thiel: "To preserve the synchrony of the sound's harmonics, all drivers must move in and out in step with each other and with the speaker's input signal. THIEL speakers accomplish this by using very wide bandwidth drivers in conjunction with special crossover systems designed to provide phase coherent transitions between drivers.
Since it is necessary to optimize separate drivers for different frequency ranges, a crossover network is needed to direct the incoming frequencies to the appropriate driver. A problem arises because any network which discriminates between frequencies will also cause the phase of the signal to be shifted, which causes the drivers to move out of step with each other."
Direct link here: http://www.thielaudio.com/THIEL_Site05/Pages/FAQs/faqtimephase.html
Steve, what is your experience listening to time-aligned speakers. Do you ever prefer them to your Wilsons?
Steve williams
Site Founder, Site Owner, Administrator
Ken i understand completely about my Gothams with my X-2s. My question pertains to speakers that have a lateral firing subwoofer with the sub driver positioined 4-5 inches behind the other drivers
Steve williams
Site Founder, Site Owner, Administrator
Jeff it is the answer to your question that has made me explore DRC with TacT etc. My biggest concern in doing this in my room is that I would probably benefit from DRC but at the expense of much of my tube magic and honestly this is something I dont want to sacrifice
Steve williams
Site Founder, Site Owner, Administrator
Jeff one last question.......
Many preamps are phase inverting such as my Lamm LL1 Signature. To correct for this the polarity of the speaker cables from the amps to the speakers is reversed.
Can you expound upon the virtues if any of a phase inverting preamp
Many preamps are phase inverting such as my Lamm LL1 Signature. To correct for this the polarity of the speaker cables from the amps to the speakers is reversed.
Can you expound upon the virtues if any of a phase inverting preamp
I really don't have an opinion on phase-inverting preamps. I have no experience with the Lamm preamps.
But Steve, back to my question: I know you've likely heard the Vandersteen 7s and the Thiel CS3.7s. These are both time-aligned speakers and I'm wondering if you've heard anything from them versus your speakers that might make you think time-aligned speakers have something to offer that yours don't.
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