# Time alignment question using distance



## Pjrm68 (Dec 7, 2013)

I've been reading a lot of the threads here about time alignment, and people seem to agree that distance is not the best way to go about it. But, here's my problem: the head unit I'm using (Pioneer AVH4000NEX) only allows you to adjust the time alignment to each speaker in inches. That's it.

So, if distance is all I have available to play around with, and the speakers (HAT Imagine 6.5, set up as components) are running passive, does anyone have any tips or advice on how to get the best possible result? I'd appreciate any help anyone has to offer. Thanks.


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## smgreen20 (Oct 13, 2006)

Ignore the numbers, adjust to what sounds right to you. I too fall in where the numbers don't sound right. I'vetried everything too, attenuation, phase..... Adjust to where it sounds centered. Do it with your eyes closed too.


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## Kevin K (Feb 11, 2013)

Use your ears like mentioned above but to help get there, this site will help you out
http://tracerite.com/calc.html


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## Pjrm68 (Dec 7, 2013)

Kevin K said:


> Use your ears like mentioned above but to help get there, this site will help you out
> http://tracerite.com/calc.html


Thanks a lot for that link. That's a great resource.


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## Kevin K (Feb 11, 2013)

Your welcome, some good friends worked on that and it's a very useful tool.


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## iamstubb (Sep 6, 2013)

Pjrm68 said:


> Thanks a lot for that link. That's a great resource.


That calculator just works on distance measurements, so it wouldn't solve your problem. It could be that TA isn't the cause of your problems. Could it be the passive setup and speakers out of phase? I found a hole in my response that I could see by my RTA. Fixing that made a difference even withou TA.


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## ZeblodS (Nov 4, 2009)

Pjrm68 said:


> does anyone have any tips or advice on how to get the best possible result?


Use :
- a computer,
- a measurement microphone (such as calibrated Dayton EMM-6),
- a sound card compatible with "world clock" on his inputs/outputs (such as Tascam US-366),
- the free software HOLMImpulse.

Put the microphone on the driver seat exactly when your head should be.
Use HOLMImpulse to measure each speaker independently with a sweep (generated by the software).
On the "impulse" part of each measure, look the sample number of the maximum of the first peak (there is an inbuild tool that give you the number automaticaly).
You have the sampling rate of the measure (44.1KHz or 48kHz depending on what you selected), the sample number, and the speed of sound (340,29m/s). You can calculate the absolute delay in ms or cm (or inches for american) with the information above, juste use your brain a little (and a calculator).
Use these absolute delay values to determine the relative delay values between each speaker, usually by setting the subwoofer at 0ms ou the driver tweeter to 0cm/0inch.

That way, if you didn't mistake, all speaker should be perfectly aligned.


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## Kevin K (Feb 11, 2013)

Passives setups are tough to get right due to distance between the mid and tweeter.
Distance is how you arrive to what delay in time you need to have to have ever driver's sound arrive at your ear at the same time. Since you have to work with your component set...as a set. You will have to pay attention to freq of each and come up with a compromise on your time alignment(distance) setting. There is some good information on this page that may help you with that. Phase angle calculation time delay frequency calculate phase lag time shift between voltage difference time of arrival ITD oscilloscope measure two signals formula angle current voltage phi phase shift time difference - sengpielaudio Sengpiel Berlin

A good solid install helps, paying attention to the driver's spec's and using full advantage to their strong points, and then tune, tune, tune. RTA like mentioned above will help show problem areas and phase issues. Best I can say is be patient and study....then enjoy.


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## sqnut (Dec 24, 2009)

ZeblodS said:


> On the "impulse" part of each measure, look the sample number of the maximum of the first peak (there is an inbuild tool that give you the number automaticaly).


For a tweeter there is a sharp peak and there is a negligible time gap between the base and the peak. For a mid there is no sharp peak and a much shallower slope. Now there is a significant time lag between base of impulse and the top of the hump.


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## 14642 (May 19, 2008)

SQNut is right. The top of the hump in a driver that has a low pass filter is NOT the initial impulse. 

Does the head unit require you to input the distance to the speaker or the desired delay in inches?


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## bobc04 (Mar 31, 2009)

i did that before with my 880prs but i agree with above. go by what you hear and not strictly by the numbers


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## Pjrm68 (Dec 7, 2013)

Andy Wehmeyer said:


> SQNut is right. The top of the hump in a driver that has a low pass filter is NOT the initial impulse.
> 
> Does the head unit require you to input the distance to the speaker or the desired delay in inches?


It asks for distance to the speaker.


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## sqnut (Dec 24, 2009)

If you're doing an impulse response, with tweeters you can go with peaks with mids go for the base of the impulse pr as close to it as you can get. Typically 12 db down from the hump is a good starting point. If however you do not have the tools for IR, basic measurements are a great way to get 90% there. The balance (appx +/- 0.06 ms) can be revisited once l/r is balanced. 

It works best when you sit and someone else measures. How accurate do you have to be? Depends on the driver you're measuring and the frequencies it is playing. So a sub playing to about 70hz at 12 db down point (6th order) means you're timing a wave 16 feet long. At a 1/4 wavelength accuracy you're looking at 4 feet. So a few inches here or there won't make a difference. You can measure the sub along the side of the car and that would be fine too.

For a midbass (assuming a 2 way) where the 12 db down point is ~ 4khz you need to be at under an inch in terms of accuracy. At this accuracy the mids will be in phase with each other and the tweeters, as long as you don't under or overlap the mids and tweets. That's one reason I never under or overlap drivers. You have an eq to control response issues.

Use the measured distance to get in the ballpark that's 90% of the way there. The last mile is best done by ear. In this example, play the 4khz PN track playing only the mids. Now now add and reduce delay (about 2 clicks either way) on any one driver. You want to set it at the loudest point. The differences can be subtle so you'll need to do a few rinse and repeats. The caveat here is since L/R have already been balanced, there should be no significant shift in image. If that happens you've gone too far.

Now do the same between the mid and tweet on one side then with the other. Add /reduce delay do on the tweeters only. 

Measuring will get you within 90% accuracy. For most folks that is enough. For the nay sayers, well maybe you measured wrong


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## sqnut (Dec 24, 2009)

Pjrm68 said:


> It asks for distance to the speaker.


That's what Andy was asking. Measure each driver, left side drivers to left ear and right to right. Measure the sub to the tip of your nose and enter the distances and you're done.

When you're setting timing, you're setting for first arrival i.e. direct sound, so left speaker to left ear and vice versa works pretty good.


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## Pjrm68 (Dec 7, 2013)

Just out of curiosity, would a JBL-MS8 do all of this for me?


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## BEAVER (May 26, 2007)

Yes and no. It'll do it, but if you don't like the results you're stuck with Them, anyway.


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## subterFUSE (Sep 21, 2009)

sqnut said:


> If you're doing an impulse response, with tweeters you can go with peaks with mids go for the base of the impulse pr as close to it as you can get. Typically 12 db down from the hump is a good starting point. If however you do not have the tools for IR, basic measurements are a great way to get 90% there. The balance (appx +/- 0.06 ms) can be revisited once l/r is balanced.


So if trying to use IR to align a mid to a tweeter, the goal would be to align the peak of the tweeter with the base of the mid (approx -12dB from peak)?


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## sqnut (Dec 24, 2009)

subterFUSE said:


> So if trying to use IR to align a mid to a tweeter, the goal would be to align the peak of the tweeter with the base of the mid (approx -12dB from peak)?


Yes that is a good starting point. Ideally you're trying to get as close to the base of the impulse on the mid, as you can.


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## sqnut (Dec 24, 2009)

End of the day one is looking for a happy medium while getting timing right. One can time drivers at say 20db i/o 12db down and the difference will be slight but you will hear it. However after all this, next time you get in the car that timing is now slightly off. 

So really, one is setting timing to a happy place where one can be in the zone every time you sit in the car. This point is tough to find if you're not tuning by ear. But unless you are an intuitive tuner chances are you'll only muck up your perfectly good measured timing chasing this. Correctly measured and implemented timing though will put one in the zone where one can play around on the eq without feeling the need to tweak the timing.


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## iamstubb (Sep 6, 2013)

sqnut said:


> End of the day one is looking for a happy median with getting timing right. One can time drivers at say 20db down the difference will be slight but you will hear it. However after all this, next time you get in the car, that timing is now slightly off.
> 
> So really, one is setting timing for a happy place where one can be in the zone every time you sit in the car. This point is tough to find if you're not tuning by ear. But unless you are an intuitive tuner chances are you'll only muck up your perfectly good measured timing chasing this. But you definitely want to be in the zone where you can play around on the eq without feeling the need to tweak your timing.


Getting the math right on time/distance is the most significant. Then things like adjusting L/R balance using the inverse square rule, and checking for phase interference using an RTA seems to lock it in and clarify it. I did have to invert the tweets for a smooth transition to mid-bass. Any other messing around seems to degrade the focus.


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## sqnut (Dec 24, 2009)

iamstubb said:


> Getting the math right on time/distance is the most significant. Then things like adjusting L/R balance using the inverse square rule, and checking for phase interference using an RTA seems to lock it in and clarify it. I did have to invert the tweets for a smooth transition to mid-bass. Any other messing around seems to degrade the focus.


It's not that complicated and if you have timing and response right you don't need to invert polarity on any driver. If you feel a polarity flip improves the sound, then you need to re-look at the timing and/or response. It's as simple as that.


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## iamstubb (Sep 6, 2013)

sqnut said:


> It's not that complicated and if you have timing and response right you don't need to invert polarity on any driver. If you feel a polarity flip improves the sound, then you need to re-look at the timing and/or response. It's as simple as that.


True, the flip is essentially a 1/2 phase timing change, isn't it? lengthening or shortening timing could accomplish the same thing unless the timing resolution of the DSP is not fine enough.


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## sqnut (Dec 24, 2009)

iamstubb said:


> True, the flip is essentially a 1/2 phase timing change, isn't it? lengthening or shortening timing could accomplish the same thing unless the timing resolution of the DSP is not fine enough.


Phase is down to timing and response. Let's say a mid is band passed 70-3khz and you're trying to get L/R in phase. Now if you set timing using 3khz as the ref point then the drivers will be phase at all frequencies below 3khz. The other aspect is the response for which you have the eq.

Flipping the polarity messes both response and timing in the pass band. With the right timing and response flipping polarity will always sound worse.


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## gijoe (Mar 25, 2008)

Getting TA set well is easy, getting it set perfectly is a bit tougher. By taking physical measurements of the distance from each driver and adjusting slightly will give very good results. Generally these can be improved upon, but it's easy to get close quickly. 

Erin has a nice calculator that gave me pretty good results, I'm not sure if it's been posted here, I'll take a look and post it if it isn't here.


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## 14642 (May 19, 2008)

1. set time alignment with a tape measure.
2. Set preliminary crossovers to keep the drivers safe
3. set crossovers. Set high pass filters to keep drivers safe. Set low pass filters in a range where dispersion of the speakers is wide. Should be the same frequency ([email protected], [email protected], for example). In cases where both conditions cannot be met, err on the side of driver safety. 
4. Check the responses with an analyzer of some sort. If a big hole appears at the crossover, change the polarity of one of the speakers. Do the same thing on the other side. Check again. 
5. EQ. Make sure the left and right side are very closely matched in frequency response and overall level. 

Listen.


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## sqnut (Dec 24, 2009)

Andy Wehmeyer said:


> 1. set time alignment with a tape measure.
> 2. Set preliminary crossovers to keep the drivers safe
> 3. set crossovers. Set high pass filters to keep drivers safe. Set low pass filters in a range where dispersion of the speakers is wide. Should be the same frequency ([email protected], [email protected], for example). In cases where both conditions cannot be met, err on the side of driver safety.
> 4. Check the responses with an analyzer of some sort. If a big hole appears at the crossover, change the polarity of one of the speakers. Do the same thing on the other side. Check again.
> ...


Measuring is good for getting 90% of the way there and I mentioned that several times, but you do need some flexibility in tweaking the last mile be ear. That is what I was explaining. I also qualified that by mentioning that if you're not sure about don't the by ear bit right don't attempt it. 99% of people wont need to.

If you have the timing and response dialed in and the drivers are playing in ranges where they are largely omni directional, then you shouldn't have a big dip at the xover point. If you do it's due to incorrect timing / response or placement of driver. Under normal conditions if things are dialed in properly one doesn't need to flip polarity.


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## BEAVER (May 26, 2007)

Andy Wehmeyer said:


> Check the responses with an analyzer of some sort. If a big hole appears at the crossover, change the polarity of one of the speakers. Do the same thing on the other side. Check again.


Which one would you reverse? Is there a hard and fast rule for this?


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## T3mpest (Dec 25, 2005)

sqnut said:


> Measuring is good for getting 90% of the way there and I mentioned that several times, but you do need some flexibility in tweaking the last mile be ear. That is what I was explaining. I also qualified that by mentioning that if you're not sure about don't the by ear bit right don't attempt it. 99% of people wont need to.
> 
> If you have the timing and response dialed in and the drivers are playing in ranges where they are largely omni directional, then you shouldn't have a big dip at the xover point. If you do it's due to incorrect timing / response or placement of driver. Under normal conditions if things are dialed in properly one doesn't need to flip polarity.


That's a question that's always been in the back of my mind as it intuitively makes sense. If drivers are properly time aligned we shouldn't need to flip phase? If the wavefront from both drivers is reaching you ears at the same time it has to be in proper phase right? Always threw me off since most processors have phase adjustement and time alignment.


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## BEAVER (May 26, 2007)

Idk about that. I have to reverse polarity on my sub or add an ungodly amount of time delay to it to make it blend... And it's the farthest driver in the system, so it shouldn't need to be delayed... Measurements seem to work well for my fronts, but not the sub...


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## sqnut (Dec 24, 2009)

T3mpest said:


> That's a question that's always been in the back of my mind as it intuitively makes sense. If drivers are properly time aligned we shouldn't need to flip phase? If the wave-front from both drivers is reaching you ears at the same time it has to be in proper phase right? Always threw me off since most processors have phase adjustement and time alignment.


Yes you're right, as long as you get the timing and response right, the phase angle should automatically fall in place. As long as the drivers are playing primarily in the omni direction zone and you have timing and response covered, you won't need to flip polarity. It's a bit of a band aid for timing, response or placement issue. 

But phase is only a small but critical part of the whole story. A part that you can never fix with any permanence. Every time you get in the car the timing and hence phase will be slightly different. So you need to think of timing as something that allows you a little bit of flexibility while keeping you in a smallish ballpark. Measuring is a great way to start.


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## pocket5s (Jan 6, 2012)

Not needing to delay the sub because it is the furthest away is a common misconception. Remember wavelengths are really big on the sub, so yes you would need to delay quite a bit if going that route. 

Unfortunately no car audio dsp has enough delay to truly make a big difference. Some however do have phase adjustments on the sub channel which effectively does the same thing. I believe Erin mentioned doing this on his helix dsp


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## T3mpest (Dec 25, 2005)

BEAVER said:


> Idk about that. I have to reverse polarity on my sub or add an ungodly amount of time delay to it to make it blend... And it's the farthest driver in the system, so it shouldn't need to be delayed... Measurements seem to work well for my fronts, but not the sub...


Did you delay your speakers to match the distance of your subwoofer? The ungodly amount of delay should be on your front stage, not your sub. Delay the closest midbass until the subbass and midbass blend. Then delay the midbasses to each other and then the tweets to that, etc. It seems a lot of times people turn the sub off when doing t/a which is why that would happen. Personally I do to get relative delays for the frontstage right. However I write those down then to the long delay needed to match the mids up to the sub, then just apply the values I found earlier to get it all matched up.

That being said, generally you can apply delay to get the frontstage phase and time coherent and then simply use phase and time alignemnt on the sub arbitrarily to get phase coherency only, and still get good results. It's a lot less of a headache to boot. Generally when doing a quick tune on my friends cars for dialy driving thats how I'll do it since it's much quicker/easier. To do the sub right you have to calculate the approximate distance to figure out how much to delay then dial it in by ear from there. Frontstage I can generally simply do by ear. Phase on subwoofers are so long you hold the button down so long it is pretty hard to do totally by ear.

My JBL MS-8 does a fanstastic job and it doesn't sweep the sub at all when doing time alignement. Phase only and it sounds fanstastic, better than 99.9% of the cars I've heard manually tuned.


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## sqnut (Dec 24, 2009)

With the sub and the mids, one can never get the phase just right unless one has the phase tweaker like the one on the Helix. But you can tweak the timing and set the response on sub and mids in the transition zone. Just these two will give you good integration and a nice low end. To the point where you're not lacking for anything.

If you're TA in m/s and the sub is the furthest speaker yes you can set the sub to 0 and then delay the near and far mids accordingly. Now if you were to add delay to the sub you would need to add equal delay to all the other drivers to keep the the timing the same. If you're TA in distance, just enter the measured distance. Integration between sub and mid is down to about 50% timing and 50% response. You can get great integration without flipping polarity.


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## BEAVER (May 26, 2007)

In my car I can use physical measurements and plug them into Erin's site and the front stage sounds great, minus the sub. At this point I can either add 7-8 ms to everything in the front or leave everything as is and flip the polarity on the sub. Both methods sound about the same to me. I'm not saying this works the same for everyone, but this is what I've found in my car, with my gear.


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## fcarpio (Apr 29, 2008)

I wrote this a while back, it will help you get there. Please note that towards the last posts I make a correction to this technique.

http://www.diymobileaudio.com/forum...5069-better-technique-ear-time-alignment.html

Compare it to the results you get from the software.

http://tracerite.com/calc.html


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## Pjrm68 (Dec 7, 2013)

fcarpio said:


> I wrote this a while back, it will help you get there. Please note that towards the last posts I make a correction to this technique.
> 
> http://www.diymobileaudio.com/forum...5069-better-technique-ear-time-alignment.html
> 
> ...


Thank you! All of the responses here have been incredibly helpful. I really appreciate it.


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## subterFUSE (Sep 21, 2009)

So during an episode of early morning insomnia I have been Googling the topic of phase alignment using delay. I came across this article which is based on Live PA systems, but I feel like the principles are probably the same.


One of the points made in the article is that output EQ adjustments affect phase, and therefore EQ needs to be set before adjusting delay to align phase between drivers. Is this correct? If this is true, then I've definitely had my order of operations wrong.  


The article also does a pretty good job of explaining how to read SPL & Phase charts and to use the Phase plot to help set delays. I'm hoping this could translate well to REW.

Thoughts?


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## sqnut (Dec 24, 2009)

subterFUSE said:


> One of the points made in the article is that output EQ adjustments affect phase, and therefore EQ needs to be set before adjusting delay to align phase between drivers. Is this correct? If this is true, then I've definitely had my order of operations wrong.
> 
> Thoughts?


You can do it both ways. If you eq first and then change the timing (TA), you will change the response as well. So you'll have to revisit the eq. Set the timing first and then use the eq and now you've messed the phase/timing a bit. One affects the other. 

It's not something you're going to get done in one iteration, so it doesn't matter what you do first. Just pick one and run with it. I do TA first.


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## Pjrm68 (Dec 7, 2013)

Thanks very much to everyone who offered suggestions about time alignment. I think I finally have it dialed in now, and it sounds one thousand percent better than it did before. 

I did it in sort of a strange way, however. I read all the posts about aligning by ear and then used a sort of shortcut to see if it would work. Surprisingly, it got me in the ballpark pretty quickly and then it was just some fine tuning from there. 

What I did was to play a pink noise CD and then just listen. Obviously, it was a pretty harsh sound coming from the speakers. Then, starting at a very low number (my head unit used inches as the measurement), I raised the number on the left rapidly until the sound of the pink noise changed slightly. It was very subtle, but it sounded like it became just a little bit less harsh. What I also noticed was that there was a very small window for this I happen. One or two clicks more and the sound became harsh again. So, I left it in the middle of the "good" range and then did the same for the right side, finding the inch measurement where the pink noise sounded just slightly less harsh. 

Then, I switched to music and listened. Even done just roughly like that, the change in clarity and separation of instruments was incredible. I then played with adjusting an inch or two up or down in the good range for each side, and that was it, except for a little EQing. 

Now, I have a nice, wide soundstage, incredible clarity, and tight, clear bass. In fact, I never knew my speakers could sound this good. So, thanks a lot to everyone who offered suggestions or links. Your advice really helped me get the kind of sound I wanted, and listening to music in the car now is an absolute pleasure.


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## bigaudiofanatic (Mar 1, 2009)

Kevin K said:


> Passives setups are tough to get right due to distance between the mid and tweeter.
> Distance is how you arrive to what delay in time you need to have to have ever driver's sound arrive at your ear at the same time. Since you have to work with your component set...as a set. You will have to pay attention to freq of each and come up with a compromise on your time alignment(distance) setting. There is some good information on this page that may help you with that. Phase angle calculation time delay frequency calculate phase lag time shift between voltage difference time of arrival ITD oscilloscope measure two signals formula angle current voltage phi phase shift time difference - sengpielaudio Sengpiel Berlin
> 
> A good solid install helps, paying attention to the driver's spec's and using full advantage to their strong points, and then tune, tune, tune. RTA like mentioned above will help show problem areas and phase issues. Best I can say is be patient and study....then enjoy.



I'm going to be in a world of hurt next week when I TA my 3 way Morels. I plan to run them active later on but not until I figure out my amp situation.


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## gijoe (Mar 25, 2008)

bigaudiofanatic said:


> I'm going to be in a world of hurt next week when I TA my 3 way Morels. I plan to run them active later on but not until I figure out my amp situation.


If you are running them passive, then your job got much easier since you have to TA them as a set. Ignore the tweeter because we don't localize sound via phase in the high frequencies, so TA has little effect on tweeters. You'll probably end up setting the TA to the midbass since that's the frequency range you'll be most sensitive to phase differences.


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## bigaudiofanatic (Mar 1, 2009)

gijoe said:


> If you are running them passive, then your job got much easier since you have to TA them as a set. Ignore the tweeter because we don't localize sound via phase in the high frequencies, so TA has little effect on tweeters. You'll probably end up setting the TA to the midbass since that's the frequency range you'll be most sensitive to phase differences.


I'm actually having a strange issue where when I time alight to the mid, I have a stage set way left directly from the tweeter. Slight adjustments don't seem to be doing anything so I might need to change to time instead of inches.


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## gijoe (Mar 25, 2008)

bigaudiofanatic said:


> I'm actually having a strange issue where when I time alight to the mid, I have a stage set way left directly from the tweeter. Slight adjustments don't seem to be doing anything so I might need to change to time instead of inches.


"Change to time instead of inches?" I don't get what you mean. You may be able to plug in either the actual distance and let the DSP calculate the delay, or calculate the delay on your own, either way it will do the same thing. TA is only part of the equation. At high frequencies we localize sound by SPL, so with the midrange and tweeters the stage will pull toward whichever side is loudest. If you set TA for the midbass, then you still need to balance the SPL for the highs. This is why active setups tend to be superior, you have independent control over each speaker, whereas with a passive setup there are only so many things you can do.


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## bigaudiofanatic (Mar 1, 2009)

gijoe said:


> "Change to time instead of inches?" I don't get what you mean. You may be able to plug in either the actual distance and let the DSP calculate the delay, or calculate the delay on your own, either way it will do the same thing. TA is only part of the equation. At high frequencies we localize sound by SPL, so with the midrange and tweeters the stage will pull toward whichever side is loudest. If you set TA for the midbass, then you still need to balance the SPL for the highs. This is why active setups tend to be superior, you have independent control over each speaker, whereas with a passive setup there are only so many things you can do.


The RF has the ability to TA in inches or in ms, I did it in inches, the option is under preferences. I've almost always done active setups, sadly the G37 molex connectors has 0 room to add wires and there is only 2 true speaker wires going through them instead of 3 sets which is what the factory actually had. :mean:


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## gijoe (Mar 25, 2008)

bigaudiofanatic said:


> The RF has the ability to TA in inches or in ms, I did it in inches, the option is under preferences. I've almost always done active setups, sadly the G37 molex connectors has 0 room to add wires and there is only 2 true speaker wires going through them instead of 3 sets which is what the factory actually had. :mean:


Ok, inches and MS will both do the same thing. If you have accurate physical measurements and the staging is still off, it's almost certainly because of the other speakers in the set. You can use the passives to attenuate the louder tweeter to try to center the stage. Do you have independent left and right EQ in that DSP? If so, you will want to use REW and a microphone to measure the responses and EQ each side to match.


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## 156546 (Feb 10, 2017)

Wow...so much misinformation in this thread.

Here's the deal. Delays compensate for distance. When the delays are set properly, then the speakers are in phase at the listening position. In order for this to work properly, all of the speakers have to be connected in the proper polarity (according to the markings--or so they all move forward with a positive voltage). 

When the delays are set properly AND the frequency response and levels of the right and left channels are matched, the center image will appear halfway between the left and the right speakers. If it doesn't, check your delay settings again with a tape measure. If they are correct and everything is in the proper polarity, adjust the LEVELS to move the center image. 

"Fine tuning" your delays to move the image just puts the speakers out of phase again. 

The tracerite thing works fine for distance measurements, but the sections for adjusting delays for crossovers and adjusting delays to move the center image don't.


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## pocket5s (Jan 6, 2012)

GotFrogs said:


> ... but the sections for adjusting delays for crossovers and adjusting delays to move the center image don't.


and that is more misinformation.


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## 156546 (Feb 10, 2017)

pocket5s said:


> and that is more misinformation.


Ok. I'll restate my position. They don't work correctly. Of course they move the image, but they also screw up the image at other frequencies. 

Delay is very simple. Samples are held in a memory buffer and released later. We use that to make sure that the sound from one speaker arrives at the same time (and therefore in phase) with the other one. The arrival time is based on distance. If you measure the distance from the left midbass dustcap and the right midbass dustcap with a tape measure, how is it possible that the measurement is wrong and that it should be readjusted by ear?


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## pocket5s (Jan 6, 2012)

GotFrogs said:


> Ok. I'll restate my position. They don't work correctly. Of course they move the image, but they also screw up the image at other frequencies.
> 
> Delay is very simple. Samples are held in a memory buffer and released later. We use that to make sure that the sound from one speaker arrives at the same time (and therefore in phase) with the other one. The arrival time is based on distance. If you measure the distance from the left midbass dustcap and the right midbass dustcap with a tape measure, how is it possible that the measurement is wrong and that it should be readjusted by ear?


The crossover section isn't about centering up an image so much as it is about getting phase between two like side speakers correct, and as stated on the site, is experimental and doesn't work for everyone. 

Your assessment of measuring two speakers at the dustcap I agree with. However I would contend that when measuring say a 3 way setup, unless the person is extremely accurate, one of those measurements is going to be off enough that requires tweaking after the fact. So, measuring is a really good start and for most, probably accurate enough to not matter. There are those that want to go to that N-th degree and measuring alone _may_ not get them there.

Honestly, for those that want that Nth degree, of those people that I know that are like that, not a single one ever uses the measurement method.


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## 156546 (Feb 10, 2017)

I'm pretty familiar with the "N-th degree" and I've used nearly every method under the sun--spatial average in real time and with sweeps, measuring impulse responses (I'm a patent holder for a method of determining the actual arrival time of a low passed signal), tape measures, lasers, frequency response sums and on and on ad infinitum.

The problem with all of this additional perceived "accuracy" is with the placement of the microphone. How does one know that it's placed precisely in the right spot that correlates best with what you hear? What happens when you move your head? Measuring impulse responses is accurate, but it's really difficult to interpret the arrival if there isn't much high frequency content in the signal. Precision isn't required at low frequencies. At high frequencies, that impulse response and getting the perfect crossover sum is only valid for one tiny spot in space and that's all undone with even slight head movements. 

If you really want to be accurate and you want a measurement that correlates well with what you hear, then you should measure impulses and interpret them correctly. Then, the frequency response should be measured with a spatial average. That would be the "Nth degree". 

Unless the levels and the frequency response of the left and right channels are precisely matched, there's no chance that setting or fine tuning delays by ear in an effort to accurately compensate for flight time is going to be more accurate than a tape measure. If you're concerned about phase at the crossover, then the frequency response of the individual speakers has to be equalized to match your target crossover response--only then can you assess phase at the crossover accurately--and the accuracy of that measurement at high frequencies depends entirely on the placement of the mic.

Then, you move your head and all of that precision is out the window...


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## pocket5s (Jan 6, 2012)

GotFrogs said:


> I'm pretty familiar with the "N-th degree" and I've used nearly every method under the sun--spatial average in real time and with sweeps, measuring impulse responses (I'm a patent holder for a method of determining the actual arrival time of a low passed signal), tape measures, lasers, frequency response sums and on and on ad infinitum.
> 
> The problem with all of this additional perceived "accuracy" is with the placement of the microphone. How does one know that it's placed precisely in the right spot that correlates best with what you hear? What happens when you move your head? Measuring impulse responses is accurate, but it's really difficult to interpret the arrival if there isn't much high frequency content in the signal. Precision isn't required at low frequencies. At high frequencies, that impulse response and getting the perfect crossover sum is only valid for one tiny spot in space and that's all undone with even slight head movements.
> 
> ...


no argument there at all. Lots of details in that response that get left of out of so many others pertaining to TA in general. 

Perhaps I should restate my original response to read: "So much context left out of that as to allow misinterpretation."

The problem with the tape measure isn't so much the tape measure, it is the person doing the measuring, as I stated before. So much room for error, especially the higher the frequency you go, as you eluded to. 

Your last paragraph there about eq-ing the drivers first, then applying and assessing the crossover, ta and such. bravo, bang on (IMO). So many make the leap right to measuring, plugging the values in to a calculator and thinking everything is perfect, then when someone listens who has a good ear and says they have ta or phase issues and they wonder why.


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## Elektra (Feb 4, 2013)

Might be a bit off topic - when you EQ do you EQ left and right from the drivers seat and must the left and right be the same response? 

I suppose this would also impact your TA as well.... 

What’s best practice in this regard? 


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## Elektra (Feb 4, 2013)

pocket5s said:


> no argument there at all. Lots of details in that response that get left of out of so many others pertaining to TA in general.
> 
> 
> 
> ...




So your saying EQ first then TA? Would TA after the fact affect your EQ? And levels? 

Would the idea be Level properly then EQ then TA? 


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## pocket5s (Jan 6, 2012)

Elektra said:


> Might be a bit off topic - when you EQ do you EQ left and right from the drivers seat and must the left and right be the same response?
> 
> I suppose this would also impact your TA as well....
> 
> ...


if you are setting up your car for one seat only (as most people do), then yes and they should ideally be as close in response as possible. 

It can affect phase at the crossover region, which TA between two drivers (mid and high or example) can help correct to some degree. The previous comments above touch on this, but don't dive in to it too much


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## Elektra (Feb 4, 2013)

pocket5s said:


> if you are setting up your car for one seat only (as most people do), then yes and they should ideally be as close in response as possible.
> 
> 
> 
> It can affect phase at the crossover region, which TA between two drivers (mid and high or example) can help correct to some degree. The previous comments above touch on this, but don't dive in to it too much




I suppose if your clever about angling your mids and tweeters so that effectively the drivers seat and passengers seat has equal off axis response technically to EQ the left and right responses the same would benefit both seats equally just the center in the passenger seat will be a little off but effectively passenger and drivers seat positions should sound more or less the same...


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## pocket5s (Jan 6, 2012)

Elektra said:


> So your saying EQ first then TA? Would TA after the fact affect your EQ? And levels?
> 
> Would the idea be Level properly then EQ then TA?
> 
> ...


some do things differently, but almost everyone I know does basic eq first. get the drivers, in their passband, to match your target curve. Then either TA or level match side to side. And yes you still TA the tweeters, it is just that level matching them has more pronounced effects at their frequency range. 

Personally I EQ first because leveling can be off if a driver has some big peaks or other crazy response.


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## pocket5s (Jan 6, 2012)

Elektra said:


> I suppose if your clever about angling your mids and tweeters so that effectively the drivers seat and passengers seat has equal off axis response technically to EQ the left and right responses the same would benefit both seats equally just the center in the passenger seat will be a little off but effectively passenger and drivers seat positions should sound more or less the same...
> 
> 
> Sent from my iPhone using Tapatalk


Good luck with that lol. if you are lucky enough for that to happen, by all means run with it and thank your lucky stars.


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## Elektra (Feb 4, 2013)

pocket5s said:


> Good luck with that lol. if you are lucky enough for that to happen, by all means run with it and thank your lucky stars.




Lol... one can only try! 


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## gijoe (Mar 25, 2008)

Elektra said:


> I suppose if your clever about angling your mids and tweeters so that effectively the drivers seat and passengers seat has equal off axis response technically to EQ the left and right responses the same would benefit both seats equally just the center in the passenger seat will be a little off but effectively passenger and drivers seat positions should sound more or less the same...
> 
> 
> Sent from my iPhone using Tapatalk


YOu will never have the left and right the same, even if you mount drivers on axis. The interior of the car is asymmetrical, so the response will vary. This is why DSPs and head units with independent left/right EQ (pioneer p99, and 80prs) are so much better than the basic active head units that are available. Once your TA is set, it's done, changing the EQ will not effect the TA. As Andy has pointed out, TA is a simple delay based on the distance from the speaker to the listening position. Both TA and EQ need to be done in order to optimize staging, but changing one will not impact the other. You just need to know if the problem is TA or EQ. If you carefully measure the distance and set TA, then any issues you have are EQ related. As long as you understand how TA works, then it doesn't really matter if you EQ or TA first. Both will need to be done, but TA is much simpler, so just measure and get it over with.


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## 156546 (Feb 10, 2017)

Elektra said:


> Might be a bit off topic - when you EQ do you EQ left and right from the drivers seat and must the left and right be the same response?
> 
> I suppose this would also impact your TA as well....
> 
> ...


If you are equalizing the whole channel (tweeter, mid and midbass, for example) with ONE EQ, then you should set the delays first. 

If you have a separate EQ for each speaker, then it's best to equalize each speaker to precisely match the frequency response and crossover target response (butterworth, linkwitz-riley, etc) and then TA (if you're measuring with impulses or trying to use delay to smooth the crossover).

But, the fact is that traditional and basic crossover design ASSUMES simultaneous arrival of the sound of each of the speakers...

So, now we're back to measuring distance with the tool we usually use to measure distance--the TAPE MEASURE. 

Here's a process that I use and that I teach to people that works. The process is the first two pages. The next 60 or so are an explanation (although not exhaustive) of why it works.

https://testgear.audiofrog.com/wp-content/uploads/2018/03/A-Straightforward-Stereo-Tuning-Process-and-Some-Notes-About-Why-it-Works.pdf


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## Elektra (Feb 4, 2013)

GotFrogs said:


> If you are equalizing the whole channel (tweeter, mid and midbass, for example) with ONE EQ, then you should set the delays first.
> 
> 
> 
> ...




I run a passive system - Focal Kit 7 via crossblock using only 2 channels to power it..

I see you say in a 3 way passive system you say measure the midbass drivers for TA? 

That’s interesting - never would have thought that... in my setup the mids and tweeters are next to each other (see pic) I would have thought to use the mids and tweeters as the reference for TA?

You mentioned getting the response for left and right the same - I presume in the drivers seat being a single seater setup... 










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## gijoe (Mar 25, 2008)

Elektra said:


> I run a passive system - Focal Kit 7 via crossblock using only 2 channels to power it..
> 
> I see you say in a 3 way passive system you say measure the midbass drivers for TA?
> 
> ...


We localize sound via phase at lower frequencies, and by amplitude at higher frequencies. So, TA for lower frequencies and level match (EQ) at higher frequencies. Of course there is a range where both are important, but it's much more important to TA mids because TA essentially aligns phase. 

Think about it this way. The wavelengths of high frequencies are so short that even slight head movements would constantly move sound in and out of phase. If we heard phase at those frequencies we would go crazy as sound would constantly move in and out of phase with every movement.


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## Elektra (Feb 4, 2013)

gijoe said:


> We localize sound via phase at lower frequencies, and by amplitude at higher frequencies. So, TA for lower frequencies and level match (EQ) at higher frequencies. Of course there is a range where both are important, but it's much more important to TA mids because TA essentially aligns phase.
> 
> 
> 
> Think about it this way. The wavelengths of high frequencies are so short that even slight head movements would constantly move sound in and out of phase. If we heard phase at those frequencies we would go crazy as sound would constantly move in and out of phase with every movement.




So you would do the mids and tweeters over midbass? 


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## gijoe (Mar 25, 2008)

Elektra said:


> So you would do the mids and tweeters over midbass?
> 
> 
> Sent from my iPhone using Tapatalk


No, TA (phase) for mids like Andy recommends. TA for tweeters won't make much (if any) difference because we don't hear phase at high frequencies. TA is a phase adjustment, you delay the signal in order to align the arrival times, putting the different sources in phase. This is important for lower frequencies, but not important for high frequencies.


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## Elektra (Feb 4, 2013)

gijoe said:


> No, TA (phase) for mids like Andy recommends. TA for tweeters won't make much (if any) difference because we don't hear phase at high frequencies. TA is a phase adjustment, you delay the signal in order to align the arrival times, putting the different sources in phase. This is important for lower frequencies, but not important for high frequencies.




Andy recommends the midbass on a 3 way... midrange on a 2 way....


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## gijoe (Mar 25, 2008)

Elektra said:


> Andy recommends the midbass on a 3 way... midrange on a 2 way....
> 
> 
> Sent from my iPhone using Tapatalk


Maybe I wasn't clear. Yes, use the low frequency driver. Again, we do not perceive location via phase at high frequencies, so TA on a tweeter does very little except for the lowest frequencies that it plays. If you have a passive crossover and can only TA the set, as opposed to each speaker, TA the low frequency driver in the set. For the high frequencies, the stage will pull toward the loudest driver (usually the one closest to you), so you may need to attenuate that tweeter more than the other side.


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## Elektra (Feb 4, 2013)

gijoe said:


> Maybe I wasn't clear. Yes, use the low frequency driver. Again, we do not perceive location via phase at high frequencies, so TA on a tweeter does very little except for the lowest frequencies that it plays. If you have a passive crossover and can only TA the set, as opposed to each speaker, TA the low frequency driver in the set. For the high frequencies, the stage will pull toward the loudest driver (usually the one closest to you), so you may need to attenuate that tweeter more than the other side.




Yeah you said mids ... was a bit confused lol! 


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## gijoe (Mar 25, 2008)

Elektra said:


> Yeah you said mids ... was a bit confused lol!
> 
> 
> Sent from my iPhone using Tapatalk


Mid, midbass, midrange, either way TA to the low frequency driver. If you have independent L/R EQ then you can use that for the high frequencies, otherwise play with the tweeter attenuation in the crossover, chances are the left and right will need to be set differently.


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## bigaudiofanatic (Mar 1, 2009)

Gotfrogs, I have to try your way, I did my TA but my stage is still way left and no where near center. I've been playing with different times so it makes sense to check gains at this point.


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## gijoe (Mar 25, 2008)

bigaudiofanatic said:


> Gotfrogs, I have to try your way, I did my TA but my stage is still way left and no where near center. I've been playing with different times so it makes sense to check gains at this point.


Like I was telling Elekra.

We localize sounds differently, depending on the frequency. For low frequencies we rely on arrival times, whichever sound reaches us first is where we perceive it as coming from, so if the midbass are playing the same content (which is most likely) whichever we hear first will be where the stage lines up. We use TA to optimize this. At high frequencies, we localize sound based on amplitude, so whichever is loudest. 

TA is simple, use a measuring tape to get the actual distance, and delay speakers based on that. Once it's done, it's done. If you make EQ, or crossover adjustments, TA will still be the same because the speaker is still the same distance away. If your TA is set based on physical measurements and the stage is still off, then you need to focus on the amplitude portion. You need the left and right sides to have the same response. You may need to adjust gains, flip switches in crossovers, and EQ. The response from identical speakers in the left and right side of the car will be very different, so independent EQ for each side is the only way to solidify the stage. Without L/R EQ, you may have low frequencies perfectly centered, and higher frequencies wander back and forth. Both TA and EQ are important to replicating the stereo effect in a car.


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## Elektra (Feb 4, 2013)

gijoe said:


> Like I was telling Elekra.
> 
> 
> 
> ...




Thank you this was eloquently explained..


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## JH1973 (Apr 21, 2017)

The tracerite calculator did my system right.I plugged in all the numbers and BAM,my image was dead center on the windshield.Never messed with it since.


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## Elektra (Feb 4, 2013)

GotFrogs said:


> If you are equalizing the whole channel (tweeter, mid and midbass, for example) with ONE EQ, then you should set the delays first.
> 
> 
> 
> ...




I read on Andy’s notes for tuning that speakers are in phase individually but can go out of phase when combined - I think that has something to do with what crossover slope you use - I see Andy likes 24db slopes...

In my situation I am bound by the crossblock (Focal Kit 7) so it uses 12db slopes...

Now I presume that if the combined speakers are out of phase - say midrange etc then we take one driver out of phase? 

The final RTA graph as I understand it if there is a dip in your graph - it means 2 things 1: it’s not time aligned properly or 2: it’s out of phase

If the fix is reverse on drivers phase (which ever shows the dip) is there a rule as to which driver should be reversed? Would it be passenger or drivers side? 

Thanks for your input..

Must say on a side note - Andy’s notes on tuning are very informative and really interesting to read as well...

Over here there a lot of good installers but very few people who can tune... 

Do tuning is done by people like me who use Andy’s notes and others to improve our systems...

I have ordered the AF Mic as personally I can’t see how anyone would get a car properly setup without one. 


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## ckirocz28 (Nov 29, 2017)

gijoe said:


> Like I was telling Elekra.
> 
> We localize sounds differently, depending on the frequency. For low frequencies we rely on arrival times, whichever sound reaches us first is where we perceive it as coming from, so if the midbass are playing the same content (which is most likely) whichever we hear first will be where the stage lines up. We use TA to optimize this. At high frequencies, we localize sound based on amplitude, so whichever is loudest.
> 
> TA is simple, use a measuring tape to get the actual distance, and delay speakers based on that. Once it's done, it's done. If you make EQ, or crossover adjustments, TA will still be the same because the speaker is still the same distance away. If your TA is set based on physical measurements and the stage is still off, then you need to focus on the amplitude portion. You need the left and right sides to have the same response. You may need to adjust gains, flip switches in crossovers, and EQ. The response from identical speakers in the left and right side of the car will be very different, so independent EQ for each side is the only way to solidify the stage. Without L/R EQ, you may have low frequencies perfectly centered, and higher frequencies wander back and forth. Both TA and EQ are important to replicating the stereo effect in a car.


Around what frequency does the localization perception change? (Where is the split between "high" and "low" frequencies?)

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