[Hanatsu]

Here's another review which is a continuation of the APL unit I reviewed some time ago (which was planned before my little ragequit on DIYMA)
. All right, here goes:

Link here: APL-Review.

Here's a link to the official homepage: TDA - Time-Domain Analysis

TDA is a measurement software with the ability to measure how time coherent your system is with a touch of a button. Incredibly easy in other words. It can also view the IR, harmonic distortion 2nd-10th order, AFR (magnitude response). This is a great tool to evaluate phase/time coherency, to troubleshoot and optimize your system.

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The system in the example below:

*2-way + sub (10" sealed, Qtc 1.2, Fsc 58Hz)
*APL1 + MiniDSP 2x4 and subwoofer controlled directly from an Alpine CDE-175R

*Crossover points:

Mids, 120Hz LR12 HPF -- 3200Hz LR24 LPF
Tweeters, 3200Hz LR24 HPF
Sub, 100Hz LR24 LPF

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1. Full system (L+R) - No EQ - No T/A (Initial crossovers set and optimized)







2D/3D/DFR View. This is basically a mess. No coherency at all and as expected no stage at all. If we take a look at the averaged measured response you can see that the peak around 500Hz correlates with the offset in delay (group delay spike).



2. This is after I've setup T/A by ear and setup EQ for both channels (see the picture above). There's still a jump in relative delay below 200Hz and this is due to the subwoofer blending with the front stage (crossed fairly high). The system sound good/balanced and center staging is great now.

EQed response and "by-ear T/A"


To verify if the APL unit did proper corrections I saved my settings and returned the system to its initial setup with no EQ applied and let the APL software do its thing. The result below:

APL corrections with the initial settings as base


As it can be seen the delay between 60-200Hz has been greatly improved and it does the job overall very good if you compare it to my tedious tuning session. Male vocals, harmonics of drums etc now stages better with increased perceived depth in stage. The jump in delay around 50-60Hz is the inherited group delay of the sub, it got some peaking due to a fairly high Qts of ~1,2. (In LEAP (modeling software) it displayed a 9ms GD peak @ 55Hz in an anechoic space.) I later improved additionally on this but forgot to save the IR...

Here's the DFR (Delay FR) of the system. This is the same thing viewed as a normal graph if you prefer such a view.



I assume the little peak at 3,2-3,4kHz is actually the crossover between mids/tweeters. The group delay of a Linkwitz-Riley 4th order filter is 0,5ms in theory so it could be viable.

After setup I confirmed the coherency once again by doing a noise / RTA average in the listening space. See the picture below:

Correlated vs Un-correlated noise and A/B difference.


This is the full system playing. Uncorrelated noise is noise recorded in mono, since most vocals and lot of other content often is mono, this represent to a large degree how the mono-FR looks. Correlated noise is affected by incorrect settings in the time domain and large dips show up which are multiples of each other at different frequencies in the magnitude response. Uncorrelated noise is a random generated noise distributed in both channels, so uncorrelated is basically stereo. This isn't affected by standing waves/incorrect T/A settings in the same manner and most often looks far better in an initial setup. By directly comparing them, you can make a rough estimate how much interference there is in the time domain (destructive interference).

For a final test I used my best setting and offset T/A by 1ms, results below:

T/A offset by 1ms


T/A offset by 1ms - Amplitude difference (full system active)


Again a mess... this is with a perfect L/R FR. T/A is very important to get right as you all probably know.

If you want a software solution that does T/A analysis for you in an easy and efficient manner this is indeed a great program!

There are several other applications for this software too, troubleshooting incorrect polarity/phase, speaker optimization etc.

 

[BlackHHR]

Rage Quit LOL

 

[claydo]

Quick question.....does the apl unit work with this program and perform corrections, or is this software independent and just a way to visually display delay? Also, can this software be used to display left right delay, or just the image of your whole system to phase align the mids, highs, lows, and sub? Sorry, more than just a quick question, but the apl unit grabbed my attention early, with price being the only thing holding me back. Does this software apply to the apl, or is it just another offering from the same company?

 

[claydo]

Ok.....asked to quick on at least one....lol. I'm guessing you would take a snapshot of each side individually.......to align the drivers of each side at the mic position, then total system to align left to right. .......hmmmm, I think?

 

[Hanatsu]

Ok.....asked to quick on at least one....lol. I'm guessing you would take a snapshot of each side individually.......to align the drivers of each side at the mic position, then total system to align left to right. .......hmmmm, I think?

I had left and right tweeters on at the same time. Then left and right mids. Don't bother T/A the drivers to each other on each side. If I'm doing it by ear I simply pull down the highpass on tweeters to the 2kHz range, then turn everything else off. Then adjust T/A until it stages in the center. Repeat for mids till they stage at the same point. Works for me every time and it sounds coherent, the measurements also confirm it. Even though in theory it shouldn't be audible due to the range most tweeters are reproducing (well into the IID-range), it is - at least if the crossover is near or at ~3kHz.

The only problem is that it can be deceiving doing it by ear because you get very easily fooled by any level difference in the higher frequencies. EQ must be precise for my method to work properly. TDA does it without having to bother with this as it only takes the delay into account, it makes the tuning process much faster and less tedious as any proper measurement do.

 

[thehatedguy]

So looking at the results, could you (a person in general) replicate the results with other measurements/tools?

And how does the whole system go together? APL to TDA to amps?

 

[Hanatsu]

To be honest I've not looked into doing such measurements as these much until now. There are methods to adjust delay by lining up the IR to eachother for example but that won't give you a complete picture of what's going on in the entire range. I'm unsure it's possible to view the relative delay with any widely available software in this manner. Individual channels can be displayed by looking at excess group delay, I do not know how combined channels measurements would look or to be interpreted as of now. TDA is great because it's so straightforward to perform the measurements and leaves little room for misinterpretation.

Sent from my Samsung Galaxy S5 using Tapatalk

 

[Kevin K]

Hanatsu, does the TDA setup need a loopback system to work or will audio out and usb mic work?

 

[Hanatsu]

Hanatsu, does the TDA setup need a loopback system to work or will audio out and usb mic work?

No loopback required, a USB mic will work fine. The only thing you have do is to place the mic at the headrest then press "measure".

 

[JoshHefnerX]

How does this software results compare to using REW as you posted here:
http://www.diymobileaudio.com/forum.../145484-measure-time-delay-t-arta-roomeq.html

Josh

 

[thehatedguy]

I think the TDA would be more similar to stuff found in the pro world like SMAART and Systune. But those don't have the ability to export files to the APL1 to do phase correction (which I think it does).

The TDA software is a pretty unique way of visualizing delay, phasing, and even speaker resonances.

If I win the lottery, I would like to have a few APL1s.

 

[thehatedguy]

SMAART 7.4 is $900 for a new license.

TDA is anywhere from $75 to $835. Something similar to SMAART in license is about $316.

Systune is about $500 for the regular and $800 for Systune Pro.

So it's cheaper than SMAART.

 

[cajunner]

SMAART 7.4 is $900 for a new license.

TDA is anywhere from $75 to $835. Something similar to SMAART in license is about $316.

Systune is about $500 for the regular and $800 for Systune Pro.

So it's cheaper than SMAART.

is the level that Hanatsu is using to generate those images, the $835 dollar package, or the bronze level down at $75?

 

[thehatedguy]

I think the functionality is probably the same at least from the mid license to the top. Though the $75 one might be as well, but at a student discount since it is an academic license.

 

[cajunner]

well, no matter, I'm not paying even $75 for a software plus hardware commitment that doesn't tie my shoelaces...




I am pretty happy with the sound the MS-2 makes, overall... heck. I probably don't even need DSP at all, I know I enjoyed my stereo over the past 30 years, with the majority of those years going no more involved than adjusting treble and bass shelving, haha...

still, a consumer dropping $835 on software just to make pretty graphics is what I'd call hard core.

 

[Jepalan]

Hanatsu, et al -

A lot of this is over my head, so please be patient with my questions.

I read through the APL website and even tried looking at the patent. For me, the best overall explanation of what TDA, and APL are doing is here -> Acoustic Power Lab :: SPFR

The various descriptions make it sound as if multiple measure points are being used but from what I read above, Hanatsu implies the mic is placed on the head rest and the SW does the rest.

Please clarify this. Is the measurement mic moved around when using the all-in-one APL correction box, or is it kept in one place? If it is kept in one place, then is the SW using time-gates and FIR to create a *virtual* multi-point measurement set?

Again, sorry if above is using technically incorrect terminology, I'm just trying to wrap my head around what this stuff is doing and why it is different.

*** EDIT: I see upon more careful review that I got confused between TDA and APL. Most of my questions were answered in Hanatsu's APL Review thread. ***

 

[Jepalan]

Sorry. I have some additional questions:

It seems that the APL1 device would be capable of (nearly) perfectly time-aligning a system, even if it is using passive crossovers. i.e. by using an FIR based complex power spectrum (phase & amplitude) measurement and correction, each frequency will be time-aligned by the processor, and the need to time-align individual drivers is minimized (or eliminated, or improved upon)?

Another question: In addition to aligning the primary path to the listener, it sounds like APL will correct for the major reflected paths. Is this true? If so, does it do this by cancelling those paths, or by aligning them at the listening point to sum with the main path?

*** EDIT: I see upon more careful review that I got confused between TDA and APL. Most of my questions were answered in Hanatsu's APL Review thread. ***

 

[Hanatsu]

is the level that Hanatsu is using to generate those images, the $835 dollar package, or the bronze level down at $75?

I don't think functionality is affected. It's just how you planning you use it, professionally or not.

 

[Hanatsu]

Hanatsu, et al -

A lot of this is over my head, so please be patient with my questions.

I read through the APL website and even tried looking at the patent. For me, the best overall explanation of what TDA, and APL are doing is here -> Acoustic Power Lab :: SPFR

The various descriptions make it sound as if multiple measure points are being used but from what I read above, Hanatsu implies the mic is placed on the head rest and the SW does the rest.

Please clarify this. Is the measurement mic moved around when using the all-in-one APL correction box, or is it kept in one place? If it is kept in one place, then is the SW using time-gates and FIR to create a *virtual* multi-point measurement set?

Again, sorry if above is using technically incorrect terminology, I'm just trying to wrap my head around what this stuff is doing and why it is different.

*** EDIT: I see upon more careful review that I got confused between TDA and APL. Most of my questions were answered in Hanatsu's APL Review thread. ***

Time domain can only be measured in one point in space. Corrections in the FR need to be averaged over a number of points though.

 

[Hanatsu]

Sorry. I have some additional questions:

It seems that the APL1 device would be capable of (nearly) perfectly time-aligning a system, even if it is using passive crossovers. i.e. by using an FIR based complex power spectrum (phase & amplitude) measurement and correction, each frequency will be time-aligned by the processor, and the need to time-align individual drivers is minimized (or eliminated, or improved upon)?

Another question: In addition to aligning the primary path to the listener, it sounds like APL will correct for the major reflected paths. Is this true? If so, does it do this by cancelling those paths, or by aligning them at the listening point to sum with the main path?

*** EDIT: I see upon more careful review that I got confused between TDA and APL. Most of my questions were answered in Hanatsu's APL Review thread. ***

The way APL measures and corrects for response irregularities makes it consider reflections in another way than just doing it "the usual way". What is does is basically to take samples of the power response at multiple spots that "creates" the sum at the listening position rather than measuring the sum itself. It does this by an impulse response, not by noise which cannot register any phase/delay information. It does fix most minimum phase regions. Non-minimum phase regions are modal dips for example (which can't be fixed by any type of processing). The minimum phase corrections increases coherency in staging since left and right side is corrected for indiviually, I believe this is the main cause for the increase in perceived depth and focus in the lower midrange.