Digital phase control data?

[BrokenEnglishGuy]

I have maybe a dumb question, but if we have the step response for a speaker in a control enviorament.. then why we can't run a program using a Windows PC as a tool for fix the phase using a '' big data ''? and delay the mid range and tweeter from the woofer? or is not that easy...? or already exist but only for windows..?..
...And then make a big data and improve these speakers with windows?


Active speakers already have the trick
Ty.

 

[Blumlein 88]

Because there is a different solution for every point in space since you have a tweeter and woofer with sound emitted from different physical locations.

If you take the distance from each speaker to any point in space, the phase difference changes when you look at point in space in another direction.

 

[BrokenEnglishGuy]

Umm, maybe i didn't elaborate properly the idea, give me one chance more please.


What i want to say if it's possible '' time aligment '' the time between the drivers, delay the frequency (?)... no..?

 

[dualazmak]

and delay the mid range and tweeter from the woofer? or is not that easy...? or already exist but only for windows..?..

Even though I do not fully understand your point/inquiry, the following my posts on my project thread would be of your interest and reference, I assume;

- Precision measurement and adjustment of time alignment for speaker (SP) units: Part-1_ Precision pulse wave matching method: #493
- Precision measurement and adjustment of time alignment for speaker (SP) units: Part-2_ Energy peak matching method: #494
- Precision measurement and adjustment of time alignment for speaker (SP) units: Part-3_ Precision single sine wave matching method in 0.1 msec accuracy: #504, #507

- Measurement of transient characteristics of Yamaha 30 cm woofer JA-3058 in sealed cabinet and Yamaha active sub-woofer YST-SW1000: #495, #497, #503, #507

- Perfect (0.1 msec precision) time alignment of all the SP drivers greatly contributes to amazing disappearance of SPs, tightness and cleanliness of the sound, and superior 3D sound stage: #520

- Not only the precision (0.1 msec level) time alignment over all the SP drivers but also SP facing directions and sound-deadening space behind the SPs plus behind our listening position would be critically important for effective (perfect?) disappearance of speakers: #687

If you would be seriously interested in the test tone signals I prepared and used in these time alignment tuning efforts, please simply PM me.

 

[RayDunzl]

What i want to say if it's possible '' time aligment '' the time between the drivers, delay the frequency (?)... no..?

FIR filters can move phase.

Room Correction example:

Preamp output showing the effect of correction filters generated by AcourateDRC applied with a miniDSP OpenDRC-DI

Black is the adjustment to frequency response, red is phase correction.

Without the filter, both would be flat lines.

If I interpret the measurement correctly, the bass is being pulled forward in time relative to the higher frequencies.

No filter, speaker frequency response and phase, at the listening position, no windowing:

Speaker output with filter:

 

[jacobacci]

acourate will do the job for you

 

[thewas]

On a loudspeaker with only one amplifier you can alternate though only the total phase which means at the crossover overlapping frequency sections the relative phase differences between the different drivers remain.

 

[dualazmak]

On a loudspeaker with only one amplifier you can alternate though only the total phase which means at the crossover overlapping frequency sections the relative phase differences between the different drivers remain.

I believe this is not always exactly true.

If you would use multichannel software DSP (XO/EQ/Delay) (like EKIO which I use) upstream in your PC, and if you would feed all of the XO-ed/EQ-ed/Dely-Adjusted digital channels into singel-DAC+single-amplifier audio system, you can achieve "Quasi-Relative-Time-Alignment" even in single-DAC + single-amp + multi-SP driver audio system.

Here, I write "Quasi-Relative-Time-Alignment" because we still need LC(R)-passive network between the amp and the SP drivers in this case.

I once have tested this approach in my reference singel-DAC+single-amplifier passive audio setup having LCR-network, and objectively confirmed that "Quasi-Relative-Time-Alignment" could be achieved.

I assume, therefore, this approach would be practically useful/worthwhile if you would like to establish time alignment between sub-woofer(s) and group of other SP drivers in ms precision/accuracy in singel-DAC+single-amplifier passive audio setup.

After that experiment, I quickly moved/departed forward, of course, as you may know, into my long journey of multichannel multi-amplifier fully active audio system with complete elimination of LC(R)-network and SP attenuators.

 

[danbei]

What is Quasi-Relative-Time-Alignment ?

 

[dualazmak]

What is Quasi-Relative-Time-Alignment ?

This is just my personal terminology.

In the setup I described above in my post #8 for single-DAC+single-Amp passive system, the established time alignment is not always exactly true since we still have LCR-network (may affect phase/delay) between amp and SP drivers; so I use "Quasi-".

Nevertheless, you may establish almost accurate time alignment between sub-woofer(s) and other SP drivers using that approach even in single-DAC+single-Amp passive system, since ms level adjustment would be just enough.

If you would like to establish 0.1 msec precision/accuracy time alignment between all the SP drivers, you need to go into multichannel multi-amplifier fully active setup with complete elimination of LC(R)-network between your amps and SP drivers, just I suggested in my post #4 above.

 

[ppataki]

What i want to say if it's possible '' time aligment '' the time between the drivers, delay the frequency (?)... no..?

Yes, that is indeed possible, even for a passive multiway loudspeaker
For example Dirac Live can do that for you

Here is an example of a 3.5-way passive speaker (Nubert nuVero 140)
Step response curve before vs after Dirac Live correction

The after-Dirac curve is highlighted + I have marked the peaks where you can see the time difference between each driver on the original curve (3 peaks) vs on the corrected curve (1 peak only) which essentially means that Dirac has 'time-aligned the drivers'

This is something that is very much audible by ear too

 

[thewas]

I believe this is not always exactly true.

What exactly is not true in my above statement? It is obvious that if you have only one channel/amp you cannot change the relative phase between the drivers at the crossover overlapping regions as you can only change the phase of both, so the relative phase there stays the same. Outside of it of course you can change the phase arbitrary (I own Acourate DRC now for over 10 years).

 

[dualazmak]

Just for clarification and our mutual common understanding, let me show a simplified schematic representation of my personal terminology Quassi-Relative-Time-Alignment in stereo audio system consists of single stereo DAC and single stereo amplifier driving multiple SP drivers;

Edit:
Actual real setup example? Yes, you may find it here on my project thread; with AHB2 or Accuphase E-460 amplifier.

 

[danbei]

Thank you it is clear to me what you mean. thewas' assertion still hold true though. Even out of the overlap region this does not address phase shifts coming from the crossover filters or the box itself (high pass filter).

 

[Hayabusa]

I have maybe a dumb question, but if we have the step response for a speaker in a control enviorament.. then why we can't run a program using a Windows PC as a tool for fix the phase using a '' big data ''? and delay the mid range and tweeter from the woofer? or is not that easy...? or already exist but only for windows..?..
...And then make a big data and improve these speakers with windows?


Active speakers already have the trick
Ty.

possible to some extend, but you will have problems where there is overlap between woofer/mid/tweeter...... not sure how to correct that....

 

[fpitas]

possible to some extend, but you will have problems where there is overlap between woofer/mid/tweeter...... not sure how to correct that....

Yes, to get proper time alignment you have to delay drivers individually. Another point for active with digital delay.

 

[MAB]

I believe this is not always exactly true.

What @thewas described is actually always true.

Regarding terms like "Quasi-Relative-Time-Alignment"

This is just my personal terminology.

Since phenomena like sound reproduction is well-described physical phenomena, I suggest it is best to not introduce terms that sound meaningful but instead confuse. I understand your active speaker system (you have documented it completely), words like "Quasi-Relative-Time-Alignment" are not a useful description of what you have.

 

[BrokenEnglishGuy]

Hi

Im a bit confused now
What i want to say is time aligment for drivers not phase


I mean why we can’t delay these bits as a member pointed above with his system he delay the time for a frequency range, lets put a example

The typical kef r3 uniq + woofer
You can delay the uniq for match the woofer?

As i readed, you cant change the overlap crossover… but im pretty sure that solution is still better than not doing anything for time aligment driver (????)

Ty

 

[fpitas]

I don't see how that would work. For example, my SEAS need 430mm delay across all frequencies to line up temporally with the horn.

 

[mdsimon2]

Hi

Im a bit confused now
What i want to say is time aligment for drivers not phase


I mean why we can’t delay these bits as a member pointed above with his system he delay the time for a frequency range, lets put a example

The typical kef r3 uniq + woofer
You can delay the uniq for match the woofer?

As i readed, you cant change the overlap crossover… but im pretty sure that solution is still better than not doing anything for time aligment driver (????)

Ty

The only reason to care about time alignment between the drivers is to ensure that they are phase synced throughout the crossover so that they sum correctly.

Even if you have perfect time alignment and phase summation between drivers a crossover will create non-minimum phase (all pass) behavior. As mentioned previously in this thread this all pass behavior can be corrected (even for a passive speaker) on-axis using a FIR filter. However, as mentioned by @Blumlein 88 such correction is ONLY valid on-axis and will not be correct off-axis.

Michael