focal tweeter tuning

.5ms = 6.8” and as further reference .1ms = 1.4”. Use this formula to estimate the delay that you will need in order to compensate for distance. To account for phase at a specific crossover frequency you would want to add or subtract delay by the length of one half of a cycle for 180 degrees. For example if the wave length of 1khz is 13.57” then a change in time alignment of about .5ms will cause a 180 degree phase shift. For a 90 degree phase shift you would want to calculate ¼ the wave length of that frequency. Google “wave length calculator” to find an applet that will do this math for you. Because wave lengths become larger as frequency gets lower the time delay amount will depend on the frequency. Remember that in real life several variables exist that will change this slightly. Use the math to get your self in the ballpark and then conduct listening tests with the cds that I recommended to finalize your settings. Read the information included with the CDs carefully. My understanding is that only hi-pass 12db crossovers invert phase. I would assume that a band pass would exhibit the behavior of a high pass crossover with inverted phase. I have searched extensively for an answer to this. I have yet to find any definitive answers. I have however found a truck load of opinions. This is a difficult one because acoustic phase can not be directly measured. When calculating time alignment always start with the second farthest speaker from you head. Make the time arrival for this speaker match the time arrival of the farthest speaker(usually your sub). Then work your way to the closest speaker. Never break this rule, or all efforts will be in vain. Many people get caught up in the high frequency speakers and forget that phase is a collective phenomenon. Start with the subs. Check out Steve Brown’s university. Google it.

If I may interject, here... speakermakers has you WAY on the right track, but if your TD device processes in the digital domain, there will be no phase issues... Input will equal output on all outputs. Keep this in mind as you relocate, "re-phase", and adjust delays.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

haemphyst wrote: If I may interject, here... speakermakers has you WAY on the right track, but if your TD device processes in the digital domain, there will be no phase issues... Input will equal output on all outputs. Keep this in mind as you relocate, "re-phase", and adjust delays.

BY TD, do you mean Time Delay? If so, I understand - my processor is digital, so I should have no phasing issues...

How would you know if the TD is digital? Does my AlpineCDA-9830 have digital TD?2013 Kia Rio -90a alternator

DDX470HD GTO14001 GTO1014D (x3)

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1/0G to GTO14001

jmelton86 wrote: How would you know if the TD is digital? Does my AlpineCDA-9830 have digital TD?

I would assume if you have a digital processor or not - if it's in a headunit, probably not.

(Hope I'm right on this)

What haemphyst says is quite possibly true. It depends on how the software was written. It can be done both ways, and is. Typically I have found that if your software includes features like selectable crossover types (Butterworth, Linkwitz-Riley, Bessel, etc.) there will be phase characteristics that mimic the analogue design. This can be of great use in the right hands when dealing with asymmetrical configurations and uneven path lengths. But it can cause mass confusion in the wrong hands. There are no hard rules on this though as far as I know. And I have found that its nearly impossible to get this information from the manufacturers. When you think about it, who’s answering the phone. Its not likely to be the guy that designed the processor, or anyone close to his pay grade. So how reliable could any information that you get be?     If you get your hands on those CDs though, it’s easy to determine proper time alignment by ear (after calculations). And like I said after all the calculations are done, and done correctly you will still most likely be off by some amount on a couple if not several of your speakers. The fine tuning here must be done by ear using material specifically recorded for this type of tuning.

One good way I set my TD with is a track from a BMW Logic7 audio test CD (highly recommended). It is just a 'click' noise that repeats over and over. It seems to be at all frequencies, so setting the door speakers to the sub is easy.2013 Kia Rio -90a alternator

DDX470HD GTO14001 GTO1014D (x3)

Big3 in 1/0G

1/0G to GTO14001

sedate wrote: Since the function is contained on the integrated circuits and microchips in the headunit, it would sort of have to be 'digital.'  This is why all CD players have a "DAC" - digital-to-analog converter that finishes the signal for the RCA's.

I think just the reading of the CD part would be digital. If you were to listen to the radio, it would not have a digital signal I wouldn't think...