Excellent information and available for free, lots of people ask lots of money for this kind of info and they behave like they have discovered usa again. Your contribution to car audio is perfect. Keep up the good work please. Thank you.
Outstanding!! Great explanation... I still hope I bought the correct DSP, a TwK-88 which does not allow me the option of an APF. Education before buying is so important.
Very interesting and easy to understand, thanks for that!... Do you have a video that explain how to match phase between speakers of different kind? Like matching mids and tweeters that are not close together?
That's cool you analyzed it. We use to always wonder why it would get so much louder with the doors open. In a couple of sedan builds I had especially. Was not nearly as noticeable in a true hatchback. (A RX7 not Rav4 etc). Now I've got a Malibu hatchback and still not got all my components or set up, but I've designed a winisd/sub box pro to get a upfiring flat box about 100cmL by 100cmW x 20cmH Roughly. Wide n flat. I'd love to update you with it's results.
I still use AllpassFilter once I learned it from dyiaudiomobile. The process of my AF with my 3ways+Sub (example crossover 80-270-2700Hz) as followings: - EQ and Time Aligntment done. - AF 2nd, Q 0.707 - Twt applied AF at Sub cross Wf (80Hz), Wf cross Mid (270Hz) - Mid applied AF at Sub cross Wf (80Hz) - Wf applied AF at Mid cross Tw (2700Hz) - Sub applied AF at Wf cross Mid (270Hz), Mid cross Tw. (2700Hz) The results of whole system is sound richer, completed. I still don't know why but it could be prevent the phase issues happen with drivers when eq and cancellation by interior of car. You should try and could explain cause you'd more experience.
What sort of crossovers are you using? Assuming you are targeting 24db LR acoustical crossovers, and your time alingment is done correctly, why add allpass filters to mess up the phase? And at frequencies those speakers are not even playing?
@@Tomzuki. Because even if he is using 24db LR they are not in phase. If you use multiple LR24 filters on a driver i.e HPF and LPF the phase doesn't align.
@@ytnimal that us simply not true. 24db crossovers sum together at 360 degrees, so they are in phase. 12db goes 180, so you would need to flip polarity on every other driver pair, 18db does 270deg iirc. If you use 24db crossovers , have them time aligned ,they should be in phase at the crossover region(the only part which matters pretty much) in most cases. just adding APFs to all of the crossover points seems like a backwards approach to me.
If your time alignment is correct and there’s still a dip in the phase. Could you just try EQ in that certain frequency out by boosting it a little bit at a time? Or that’s not the reasonable or correct way to do it I need to apply an all Pass filter instead?
When summing the subwoofer and right or left full, I'm seeing a buildup at 200hz. This is the electric input signal in a BMW M440i with the HK system and a Helix MatchUp 10DSP piggybacked. Using the input EQ in DSP Tool has no effect. Would an all pass filter flatten this buildup?
In your case it might be just incorrectly choosen individual targets or not adjusted levels. All pass is not meant to be used as an EQ. I would go back and start over with individual EQ and level matching.
I’m at a complete loss at this point. I found your email on another set of comments from another video. I have my own TH-cam channel so I’m going to make a video for you set it to private and send you the link through email I’ve got so many questions to the point where I just don’t know what to do anymore
When we use a narrow bandpass, e.g. for midbass drivers, the phase is naturally shifting even with LR24 crossovers (I usually check what it does in Helix electrical phase) In my case, I need to use a 90° phase shift for sub (which I believe is also an AP). Should I use these phase sliders or rather adjust timing as well? Also, with LR24 crossovers, one driver is 360°out of phase which sums flat but it is one full wavelength ahead. Some people use AP filters at the XO points to account for that, is that a valid approach?
Well, first of all you need to make sure that the TA is set right, that is that all the drivers start at t=0. And if further adjustments are needed, you can use AP filters.
Cascading the xover filters (if the processor can do it) can help for the narrow passband issue where the phase shift carries to the next driver. APF will not fix the one wavelength ahead issue of the LR24 xover - it actually adds phase shift in the same direction as the xover. It can be remedied with additional delay to the HP'd driver approx equal to 1 period of the wavelength.... or Dirac / FIR type processor can remove the phase wraps at the xover completely if configured properly
@@rccotrone3391 so the question would be, should we add extra time delay to account for the lr24 one wave length ahead phase shift? Because in typical 4 way system, the tweeters would be three cycles ahead compared to the sub.
@@viko_drapaktypically not needed on tweeters. Makes the most difference in the lower freqs - sub- midbass xover in a typical 4way. But if done for tweets it would be 3cycles but at the diff xover freqs
I guess you're using all pass a lot. Because you are using Helix dsp Phase slider - which is basically based on 2nd order all pass with variable corner frequency
Funny enough we DO hear phase above 1k. I have done an experiment at home. Try yourself with a proper home system. Introduce a allpass filter above 1k and ab-test it. You can easily hear the difference. And it's substantial. Center phantom image move up and down and spreads diagonally depending on phase filter.
Well, based on your experiment, you screwed up the phase relationship that you have in your home system. Of course you're gonna hear that. I am talking more about cars where at higher frequencies you have so many reflections, that the phase changes depending on the location of your head. Car and home environments are not the same...
@@RAW-CAt i position and aim tweeters in a way that i get almost zero reflections in a car. and i was always thinking the same as you. now my mind have changed a bit :) anyway - you can try the same experiment in the car - make tweeters "in time in phase" and try to introduce allpass filters of different kinds - i am pretty sure you will hear the difference. i know the phase on tweeters is hard to align :) i have spent a lot of time positioning and aiming tweeters. phase graph is not perfect still, but summation is quite good anyways and center image is almost perfect now.
Don't do the sweep with 0dB setting in REW for the sweep. It may clip your interface. Leave it at -12dB. If the signal is not loud enough, use the master volume on the interface. This is way safer than raising the sweep level in REW.
Excellent information and available for free, lots of people ask lots of money for this kind of info and they behave like they have discovered usa again. Your contribution to car audio is perfect. Keep up the good work please. Thank you.
You have no idea how helpful these videos are, it makes an extremely complicated topic relatively easy to understand
the topics are not complicated , the people teaching makes them complicated, RAW-CAT is genius
I appreciate the content! I wish you would group all your training/explanation videos into a playlist for your channel. Keep up the good work.
I am planing to do that for quite some time now🙃
Great video, I just started learning about all-pass, and didn't really know where to start, you explained this very well!
Thanks for sharing!
awesome! i have been a little bit "fuzzy" on my understanding of APFs. this was very clear and concise. thank you.
You are a great teacher! Thank you for sharing your knowledge! I am excited to use this to tune my own car.
And never mind. And the last minute of the video you answered my question.
Another very informative video. Great job 👍
great info. thanks again
big stuff. amazing work
Outstanding!! Great explanation... I still hope I bought the correct DSP, a TwK-88 which does not allow me the option of an APF. Education before buying is so important.
Very interesting and easy to understand, thanks for that!... Do you have a video that explain how to match phase between speakers of different kind? Like matching mids and tweeters that are not close together?
One of my first videos is about that "phase issues and how to solve them".
Fantastic. A perfect explanation.
Vraiment MERCI. J'ai enfin compris cette saloperie de AllPass filtre grâce à cette vidéo 🙏🙏🙏
That's cool you analyzed it. We use to always wonder why it would get so much louder with the doors open. In a couple of sedan builds I had especially. Was not nearly as noticeable in a true hatchback. (A RX7 not Rav4 etc). Now I've got a Malibu hatchback and still not got all my components or set up, but I've designed a winisd/sub box pro to get a upfiring flat box about 100cmL by 100cmW x 20cmH Roughly. Wide n flat. I'd love to update you with it's results.
Excellent video.
Good job explaining this madness, thx a lot!
Very clear explanation!!!
Dėkoju, labai informatyvu!
I still use AllpassFilter once I learned it from dyiaudiomobile. The process of my AF with my 3ways+Sub (example crossover 80-270-2700Hz) as followings:
- EQ and Time Aligntment done.
- AF 2nd, Q 0.707
- Twt applied AF at Sub cross Wf (80Hz), Wf cross Mid (270Hz)
- Mid applied AF at Sub cross Wf (80Hz)
- Wf applied AF at Mid cross Tw (2700Hz)
- Sub applied AF at Wf cross Mid (270Hz), Mid cross Tw. (2700Hz)
The results of whole system is sound richer, completed. I still don't know why but it could be prevent the phase issues happen with drivers when eq and cancellation by interior of car. You should try and could explain cause you'd more experience.
Do you have a link to that thread? Didn't understand what you meant by twt applied apf at sub
What sort of crossovers are you using? Assuming you are targeting 24db LR acoustical crossovers, and your time alingment is done correctly, why add allpass filters to mess up the phase? And at frequencies those speakers are not even playing?
@@Tomzuki. Because even if he is using 24db LR they are not in phase. If you use multiple LR24 filters on a driver i.e HPF and LPF the phase doesn't align.
why?
@@ytnimal that us simply not true. 24db crossovers sum together at 360 degrees, so they are in phase. 12db goes 180, so you would need to flip polarity on every other driver pair, 18db does 270deg iirc.
If you use 24db crossovers , have them time aligned ,they should be in phase at the crossover region(the only part which matters pretty much) in most cases.
just adding APFs to all of the crossover points seems like a backwards approach to me.
Very useful video
as always brilliant content thank you
If your time alignment is correct and there’s still a dip in the phase. Could you just try EQ in that certain frequency out by boosting it a little bit at a time? Or that’s not the reasonable or correct way to do it I need to apply an all Pass filter instead?
How would I know if they are perfectly time aligned? Can phase be measures with a USB mic without loopback, like a UMIK-1?
Yes, if using acoustical timing reference.
When summing the subwoofer and right or left full, I'm seeing a buildup at 200hz. This is the electric input signal in a BMW M440i with the HK system and a Helix MatchUp 10DSP piggybacked. Using the input EQ in DSP Tool has no effect. Would an all pass filter flatten this buildup?
In your case it might be just incorrectly choosen individual targets or not adjusted levels. All pass is not meant to be used as an EQ. I would go back and start over with individual EQ and level matching.
Another excellent video! Quick question, how did you determine that you need 10ms of offset?
I noticed that my measurement didn't start at 0. Took 10ms to add to have it starting at 0.
Why dont you just play with phase slider? Wont it be the same result?
Slider applies phase shift differently than a specific band at a specified frequency.
I’m at a complete loss at this point.
I found your email on another set of comments from another video.
I have my own TH-cam channel so I’m going to make a video for you set it to private and send you the link through email
I’ve got so many questions to the point where I just don’t know what to do anymore
When we use a narrow bandpass, e.g. for midbass drivers, the phase is naturally shifting even with LR24 crossovers (I usually check what it does in Helix electrical phase) In my case, I need to use a 90° phase shift for sub (which I believe is also an AP). Should I use these phase sliders or rather adjust timing as well? Also, with LR24 crossovers, one driver is 360°out of phase which sums flat but it is one full wavelength ahead. Some people use AP filters at the XO points to account for that, is that a valid approach?
Well, first of all you need to make sure that the TA is set right, that is that all the drivers start at t=0. And if further adjustments are needed, you can use AP filters.
Cascading the xover filters (if the processor can do it) can help for the narrow passband issue where the phase shift carries to the next driver. APF will not fix the one wavelength ahead issue of the LR24 xover - it actually adds phase shift in the same direction as the xover. It can be remedied with additional delay to the HP'd driver approx equal to 1 period of the wavelength.... or Dirac / FIR type processor can remove the phase wraps at the xover completely if configured properly
@@rccotrone3391 so the question would be, should we add extra time delay to account for the lr24 one wave length ahead phase shift? Because in typical 4 way system, the tweeters would be three cycles ahead compared to the sub.
@@viko_drapaktypically not needed on tweeters. Makes the most difference in the lower freqs - sub- midbass xover in a typical 4way. But if done for tweets it would be 3cycles but at the diff xover freqs
Alpine 0850 allpass filter nott available how can i handle the summation?
You can't. Just do the best that you can with the time/phase alignment.
What’s your opinion on remote tuning and do you do them ?
Remote tuning is a great option when you live in a remote area with no tuners around you. Yes, I can tune remotely.
I guess you're using all pass a lot.
Because you are using Helix dsp Phase slider - which is basically based on 2nd order all pass with variable corner frequency
That is literally the only case I ever used an all pass filter.
Funny enough we DO hear phase above 1k. I have done an experiment at home. Try yourself with a proper home system. Introduce a allpass filter above 1k and ab-test it. You can easily hear the difference. And it's substantial. Center phantom image move up and down and spreads diagonally depending on phase filter.
Well, based on your experiment, you screwed up the phase relationship that you have in your home system. Of course you're gonna hear that. I am talking more about cars where at higher frequencies you have so many reflections, that the phase changes depending on the location of your head. Car and home environments are not the same...
@@RAW-CAt i position and aim tweeters in a way that i get almost zero reflections in a car. and i was always thinking the same as you. now my mind have changed a bit :) anyway - you can try the same experiment in the car - make tweeters "in time in phase" and try to introduce allpass filters of different kinds - i am pretty sure you will hear the difference.
i know the phase on tweeters is hard to align :) i have spent a lot of time positioning and aiming tweeters. phase graph is not perfect still, but summation is quite good anyways and center image is almost perfect now.
Usados en sistemas de audio de tour por años
Don't do the sweep with 0dB setting in REW for the sweep. It may clip your interface.
Leave it at -12dB. If the signal is not loud enough, use the master volume on the interface. This is way safer than raising the sweep level in REW.
My interface does not clip at 0dBFS, I tested that a while ago. It's clean all the way up.
Merci !
Just sent you an email
Titled “need Help “ check your spam folder it’s coming from United States
Will check it👍
@@RAW-CAt biting my nails , lol