Home Theater Forum and Systems banner

Another time alignment how does this look thread

10K views 54 replies 5 participants last post by  jtalden 
#1 ·
Attempting to perform t/a using a UMIK-1 & Rew. I've read probably a 100 post & spent hours researching the how's & why's. While they were extremely helpful, I'm still left a little unsure about the timing of my tweeters. So I'm attaching my file & if any one would be kind enough to take a quick glance & see if everything looks acoustically lined up per the measurements I'e achieved, I would appreciate it very much. And for a quick glance I'll attach some pics as well.
 

Attachments

See less See more
5
#2 ·
I've not seen measurements like this for time alignment. Possibly there is a method, but I can't imagine how it can be done from this data. It does suggest there is no gross timing error from the positions of the impulses.

You swept 1000-1001 Hz for the MR and 3000-3001 Hz for the TW. Normally the sweeps are full range, or at a minimum the width of the XO range for both drivers.

There is a method discussed here long ago with a narrow range sweeps centered on the acoustic XO frequency, but I have too little experience with it to be sure it will work well in all situations.

The file is labeled as 'Truck' so it may be impossible to align MR to TW using my normal method. If you want me to attempt to check your settings new measurements would be needed. I can provide detailed measurement requirements if you identify the drivers and XO's employed.
 
#3 ·
The thread I ended up following for T/A is: http://www.diymobileaudio.com/forum...g-impulse-response-ta-using-rew-umik-1-a.html

I'm attempting to align JBL components for my setup in my vehicle. There a set of 6.5" woofers located in the door panel & a 1" tweeter located in the dash. I can either run a HDMI to my headunit & send signals out that way or run rca's to my MiniDsp C-DSP. If you could provide any details I'd greatly appreciate any feedback eager to learn & if someone like yourself is willing to help. I'm all ears.
 
#5 ·
Thanks for the link. I just gave it a quick scan. The logic of this method is still not entirely clear to me. It would seem to align the timing of the MR and TW at 2 different frequencies (1000 and 3000) rather than at the acoustic XO frequency. If those 2 frequencies are chosen the middle of bandpass range of each driver I thinking the timing result may be pretty accurate. I cannot be sure how close it is. In any case, it does provide a way to assure the delays are close to the correct timing.

My normal method has not been very effective in several auto applications due to the strong early reflections so it may not be much use here. A fallback is to get a reasonably close alignment as you have done already and then either just except it or possibly see if it can be fine tuned.

> If you want me to try confirm it is good as is, or suggest an adjustment:
Sweep each of the 4 drivers individually using full range sweeps (minimum sweep range is XO frequency ±2 octaves) with REW acoustic timing activated. Leave your current XO and delay timing in place.
[So, if your XO is set to 2k, set the sweep to a minimum of 500-8000 Hz.]
Sweep:
L-W (left Woofer)
R-W
L-T
R-T

I can work from that info if you post the mdat file.
> You can confirm timing yourself with this same set of measurements along with the 2 additional ones:
L-W + L-T (left channel)
R-W + R-T

For each channel use the REW SPL overlay chart to confirm that the gap in the rolloff of the W and T (XO range) is well filled by the W + T trace.
If it isn't then increase the delay of the W in small increments (~0.03 ms for a 2K XO) and remeasure W + T. Do that for 7 increments (8 different W delays) and chose the delay that provide the best SPL fill in the XO range. It is best to chose a W delay that is the same value for both channels so there may be an compromise W delay choice needed between the 2 channels.​

Below is an example of an overlay chart showing good SPL fill in each of the 3 XO ranges:
 

Attachments

#6 ·
Perfect! Thanks for your response. I'll get back out & take some more measurements. I see what you're getting at. The method described in that thread generated anomalies when attempting to measure as well. I would get different readings almost every-other measurement requiring to take several measurements & eventually you would see a pattern.
There is also this articl published my MiniDSP, this method was unsuccessful for me as well. https://www.minidsp.com/applications/auto-eq-with-rew/measuring-time-delay
I think if a loopback was used it would work, but as an acoustical reference is being use it produced results that were inconsistent, just like mentioned above.
 
#7 ·
That's a concern... I must have missed that bit. This is a problem for my normal analysis method.

The first requirement is that we should be able to remeasure a driver several times in a given setup and get the same impulse location on the chart. So, if the impulse position is moving position in repeated measurements it is a problem. You should have selected one of the 2 tweeters for the reference. If a driver's impulse moves using that reference then try using the other tweeter for the reference. If neither tweeter is stable as the reference then it is a problem for any of the common timing methods.

Can you show me several repeated measurements of the better tweeter for stability using it both as the reference and as the measurement driver? Your 'several measurements to see a pattern' method may work if there is only occasional outliers. If you have sorted through all this and are satisfied with your ability to selecting 'good' measurements for the timing analysis then we can just use those good measurements.

If we think it is too random then possibly only a loopback cable and XLR mic setup will work.

> Now thinking of the trial and error process that was the second bullet in Post-5:
That process will still work just fine so long as you feel the initial delay timing you have found is good. If those starting points (delays set) are good as shown in the final chart in Post-1 then the 8 increment process can be done with out even using the acoustic timing. We are just offsetting a known time increment from a known good starting point and checking the impact on SPL. The best XO range SPL fill is the best answer. Acoustic timing on, or off, is not an issue in this method.
 
#8 ·
@jtalden
I'm attaching my mdat file. I took measurements in the following order.
FRT as ref
FRM
FLM
FLT
I then ran a pass with the FRT+FRM & FLT+FLM.
Note: All t/a settings remained(the t/a settings I came up with using the method I posted to)
All X-over remained in place, I have the TWT's & MID's crossed at 3,000.
Please see if you can work some magic. I still have some level balancing & eq to do, but I want to get my x-overs & t/a done first.
 

Attachments

#9 ·
I analyzed this 3 kHz XO data:
> I noted that the timing is not the same as the initial charts you posted, but the difference is relatively small and probably the result of a slightly different mic position. Thinking through this, I presume that in many, if not most all, car/truck situations the midrange and tweeters are separated from each other by a significant distance. They are also often separated both vertically and horizontally and the left vs right channel geometry is very different. In this situation it takes only a small mic position difference to have a significant impact on 3 kHz XO timing. [This shows my lack of experience in car/truck setups as I am now just thinking through the impact of all this.]
> My normal timing method is completely unsuitable for this situation. The strong early reflections of the tweeter overwhelms its direct sound.
> I did adjust timing using a couple of different approaches and checked the impact on the SPL. Of course a minor SPL improvement is possible at the exact XO frequency when the timing is corrected for that exact mic location, but the improvement is not uniform over the XO range and is not likely to impact the sound quality.

So my analysis is:
> Your current timing is very good in setting the basic sound arrival time for the 4 drivers at the mic location.
> It is not helpful to fine tune the timing further due to the basic geometric considerations:
1. The 2 ear locations are significantly different from the mic locations regarding timing.
2. It takes only very small head position change to significantly change the effective timing.​

I thus conclude that I cannot suggest an alternate timing that is likely to provide a significant improvement to the current timing.
 
#12 ·
I understand correctly you are only asking if the 2 tweeters are delayed properly for sound to arrive at the mic location at the same time?

If so:
> Acoustic timing is on as it should be so this data can be used.
> You have measured 1000-1001 Hz.
[This seems a strange method and frequency for tweeters. This is below the XO frequency for most tweeters and the sweep range is too narrow.]
We can try to use this data anyway:
> For tweeter to tweeter timing alignment (2 identical drivers in different channels) we can just look at either the Impulse chart or the ETC chart.
> For car timing situation the ETC overlay is probably the easier chart to use.

So looking at the ETC chart:
It appears the ETC of L-TW is leading the R-TW by about 2.8 ms.
Text Green Line Plot Diagram


Shifting a copy of the L-TW by -2.8 ms (an additional delay) results in better alignment of the peak energy from the 2 TWs.
Text Green Line Plot Slope


> The issues here are:
  • This is at 1000 Hz and we don't know what is happening at any other frequency. The arrival at another frequency can vary greatly in this type of situation.
  • The TW peak energy arrival is influenced by all the bouncing around of the sound that occurs in a typical car application. This may be as good or better then using the Impulse to align speakers in a car application.
  • It would be more common/logical/traditional to align the initial rise of the 2 impulses instead of the 2 ETC's. Doing it that way the needed L-TW delay would be 3.1 ms.
  • Looking at the Impulse chart the polarity of the 2 tweeters appears to be reversed. That is; we would need to invert one of the TWs to agree with the polarity of the other one. The problem is again that this may only be the case at this one frequency. The other frequencies may provide a different story. The ETC chart is no help in polarity determination as it is always plotted as an absolute value.
Suggestions:
  • If the polarity is wired correctly then that is the best indicator. This data is too narrow to really determine polarity with any confidence. The polarity reverses at different frequencies due to reflected sound in the car.
  • If the geometry (difference in measured distances from the Mic to the 2 TW's supports a 2.8-3.1 ms change to the L-TW your delay settings then this is an appropriate adjustment. If not, the measured distance difference is the better method. Your notes seem to indicate the R-TW speaker is currently delayed 1.46 ms which seems backward to me. If the R-TW is reset to 0 and L-TW is delayed the 1.46 ms then that is a difference of 2.92 ms or about the same range as my recommended adjustment. Possibly you just delayed the wrong TW?

If you want to confirm the delay setting it is better to measure as:
> Acoustic timing on.
> XO set on.
> Sweep set full range (or a minimum of XO frequency to 18k Hz).
> For timing analysis it is helpful to have a reasonably smooth frequency response. It is thus helpful to do some rough EQ work on the TW response if it is currently very irregular.
 
#13 · (Edited)
Thanks jtalden!

I will try to do a full measurement of Tweeters/Mids/Woofers later. I guess part of the confusion could be that you are thinking this is a LHD car. Its a Right Hand Drive car. So the right tweeter would be delayed more then the left.

I will try to capture all the data with the reference timing on. I seem to be having issues getting it to run once I enable the option. It seems to hang after reaching 19% or I get a waiting for reference signal prompt. So I was hoping that I get a sense of how good or bad my TA is by just capturing the signal without timing reference since the plots seems rather consistent. In the meantime, thanks again.

[/LIST]
[/INDENT]
Suggestions:
  • If the polarity is wired correctly then that is the best indicator. This data is too narrow to really determine polarity with any confidence. The polarity reverses at different frequencies due to reflected sound in the car.
  • If the geometry (difference in measured distances from the Mic to the 2 TW's supports a 2.8-3.1 ms change to the L-TW your delay settings then this is an appropriate adjustment. If not, the measured distance difference is the better method. Your notes seem to indicate the R-TW speaker is currently delayed 1.46 ms which seems backward to me. If the R-TW is reset to 0 and L-TW is delayed the 1.46 ms then that is a difference of 2.92 ms or about the same range as my recommended adjustment. Possibly you just delayed the wrong TW?

If you want to confirm the delay setting it is better to measure as:
> Acoustic timing on.
> XO set on.
> Sweep set full range (or a minimum of XO frequency to 18k Hz).
> For timing analysis it is helpful to have a reasonably smooth frequency response. It is thus helpful to do some rough EQ work on the TW response if it is currently very irregular.
 
#14 ·
Not sure why. I just cant seem to get the reference timing to work. it just hangs at 19%. So I just measured my 3 way active in sequence of LW RW LM RM LT RT in my RHD car. I inverted both my tweeters just to see if it made a difference compared to yesterdays tweeter only measurement.

I am looking at my graphs now to see if it made any difference at my crossover of 3.5k
 

Attachments

#15 ·
Confused? Me? Hmm, RHD... I'll try turning around to face the other direction and see if that helps me make any better sense of this. :R

2.5 ms + 3ms would then seem to be too much. Maybe you drive a large mobile home... :)

More seriously, I agree there appears to be a problem with the acoustic timing. I will look at he new data to see if it helps us in any way. It may take a couple off day as I am tied up with other matters at the moment.

If you can't get repeatable measurements using either TW for the reference, then there may not be much we can do beyond setting the delay to the measured difference. I would expect that to be a good setting for a car application.
 
#18 ·
I am still not getting if I am using this function correctly. Please let me know if I am getting this right.

After connecting my headphone/output from my notebook via a 3.5mm to 3,5mm input on my car, I will start REW.

1. Go to Preferences > Analysis. Choose "Acoustic Timing Reference" from the drop down menu

2. Go to Preferences > Soundcard for the "Output Device" choose my soundcard in the drop down menu.

3. For the "Output" choose speaker. The drop down box that contains "Left" "Right" or "Both". I choose both. Is this correct?

4. Make sure Mic is recognized. Close Preferences

Now go to Measurement, and this is where I am also not sure what I should be doing. I can mute any of my 3 way active speakers. The furthers speaker is my left mid (RHD car) but I understand the reference speaker should be a tweeter. So Left tweeter should be the best reference.

So in the measurement, I should use 5k to 12k as the sweep? Speaker output as both and reference speaker as Left. I then mute all except both my tweeter and click on wait for reference speaker?

After this, whats my next step? How do I align say my right mid to the left tweeter and what sweep frequency should I use? I see some instructions which as that we disable all crossovers on the DSP. Is this neccessary?

Thanks!
 
#20 · (Edited)
After this, whats my next step? How do I align say my right mid to the left tweeter and what sweep frequency should I use? I see some instructions which as that we disable all crossovers on the DSP. Is this neccessary?
> All XO's should always be active or any measurements are useless. Also, the drivers may be damaged. [XO's impact the timing alignment.]
> I just sweep full range for all measurements. I know of no advantage to reducing the range.
> To time align the L-TW to the L-MR switch the reference the R-TW:
Reference channel = Right
Measurement Channel = Left
> Measure L-TW (mute the left MR and W)
> Measure L-MR (mute the left W and TW)

If one of the TWs is not repeatable as the reference then it is a little harder. We can cover that if needed.
 
#19 ·
> The Reference channel can be either channel L or R.
That channel TW has to be active - not muted. This same TW is used as reference for all measurements no matter which measurement channel or driver is being measured. Pick the TW that provides repeatable results as the reference TW. Either one should work in most cases. Assume We select L-TW for discussing below.

> The measurement channel contains the driver(s) we are measuring.

So, when are measuring the L-TW:
Reference = Left
Measurement = Left

So when are measuring the R-TW:
Reference = Left
Measurement = Right

There is never a reason to select 'Both' channel as 'measurement' when doing time alignment work. We would get the both TW's measured together if we did that in this example.
 
#22 ·
Yes, that's right. If you are checking timing between 2 drivers within a channel, use the other channel TW for the reference. Otherwise the measurement TW would also play along with the W and MR during their measurements.

I don't know what you mean by your 'default' sweep range. We set the range to whatever makes sense for the experiment. I use a 20-20k range for timing studies as that is the working range of the speaker drivers I use. 'Full range' is full range of the channel capability, not full range of the REW sweep capabilities. If the woofer is flat down to 40 Hz and the TW flat to 18 kHz Then a reasonable range is maybe 20-20k. It is not recommended to set 2-24k range for example. The woofer may not be happy with that and we don't care what happens above 20k, it out of our hearing range.

When using full range sweeps we don't have to decide what setting range is needed for this or that XO timing evaluation. It saves time and reduces the mistakes.
 
#24 ·
I don't know what you mean by your 'default' sweep range. We set the range to whatever makes sense for the experiment. I use a 20-20k range for timing studies as that is the working range of the speaker drivers I use. 'Full range' is full range of the channel capability, not full range of the REW sweep capabilities. If the woofer is flat down to 40 Hz and the TW flat to 18 kHz Then a reasonable range is maybe 20-20k. It is not recommended to set 2-24k range for example. The woofer may not be happy with that and we don't care what happens above 20k, it out of our hearing range.

When using full range sweeps we don't have to decide what setting range is needed for this or that XO timing evaluation. It saves time and reduces the mistakes.

As I will be muting the drivers that I am not testing for TA, I would gather that the full sweep would then be in my case, be say 20hz to 300hz for my woofer (250hz lr24 crossover), 200-4K for my mid (lp 250hz lr24 and hp 3.5K lr24) and 3K to 20K for my tweeters (hp 3.5K lr24), Just a slight overlap at the crossover point.

Is this right?
 
#23 ·
I just took quick look at the last data:
> The TW impulse looks good in both channels so probably either TW will work fine as the reference.
> Without confidence in the timing reference there is no timing recommendation possible using this data.
> The current chosen sweep ranges are too narrow to cover the entire XO ranges. Please simplify and use full range measurements for all measurements.
> The SPL test level is higher than necessary. The same results will be found with SPL levels averaging roughly 75dB.
 
#25 ·
Got the reference timing working. It seems like using mt LT as reference, my right Tweeter and mid are around 0.06-0.08ms faster then my RT which should be within margins of error. RW is 5-6ms slower. But I think I cant do much about that.

However, if I take my RT as reference, and compare it to my left mid, it is off by 2.5ms I forgot to take my right tweeter measurement. But I am almost sure my left TMW are quite in alignment when I was checking using another tool TDA.

Let me know if I am measuring and reading this right. I will redo another measurement tomorrow. Thanks!
 

Attachments

#27 ·
Got the reference timing working. It seems like using mt LT as reference, my right Tweeter and mid are around 0.06-0.08ms faster then my RT which should be within margins of error. RW is 5-6ms slower. But I think I cant do much about that.

However, if I take my RT as reference, and compare it to my left mid, it is off by 2.5ms I forgot to take my right tweeter measurement. But I am almost sure my left TMW are quite in alignment when I was checking using another tool TDA.

Let me know if I am measuring and reading this right. I will redo another measurement tomorrow. Thanks!
> What is an mt LT? It has to be a Tweeter for the reference channel.
> How do you know the reference is repeatable? I do not really understand your comments. Let's just start over from the beginning to be sure we are doing this right.
Please follow Post 26 instructions to confirm the repeatability of the 2 TW when use as a reference.
Post the 2 overlay impulse charts, one showing the 6 L-TW impulses and one showing the 6 R-TW impulses.
I will then detail the next steps.
 
#29 ·
Well Done!
> Either TW works well as the timing reference.
> The delay that is current set between the L and R channels is very good.
> See charts below.

L-TW Impulse repeatability is excellent:
Text Green Line Font Plot


R-TW Impulse repeatability is excellent:
Text Line Font Plot Parallel


Current delay difference between the L and R channels is excellent (~0.19 ms or ~7 mm).
Text Line Font Plot Parallel


SPL chart is relatively normal with the exception that the noise level in the lower frequencies is maybe 10dB higher than I would have expected. There is an additional noise disturbance in the 35 Hz range that may be the result of an external noise or possibly it is a noise source within the measuring system. It is very unlikely to be an actual output of the TW. The general downward slope from the low to high frequencies of the noise level is common to many measuring systems. The output through the TW operating range is normal.
Text Line Plot Purple Slope


Step 2: Confirm delays between the drivers.
I will detail this next.
 
#30 ·
Step 2.
General setup for all Step 2 testing:
> Protect/save/record all current driver delay settings so that delay adjustments calculated from this experimentation can be made to them.
[I will need all these current delay settings in order to confirm the analysis and provide the adjustments needed.]
> All XO's = Active
> REW acoustic timing = On
> All sweeps = 20-20k Hz

Step 2.1. Determine driver delay adjustments needed for Left Channel
> Reference Channel = Right channel
> Measurement channel = Left channel
> Mute all drivers except R-TW and L-TW
> Measure (label as L-TW)
> Mute all drivers except R-TW and L-MR
> Measure (label as L-MR)
> Mute all drivers except R-TW and L-W
> Measure (label as L-W)
> Save and Post these 3 measurements as an mdat file for analysis.

Step 2.2. Determine driver delay adjustments needed for Right Channel
> Reference Channel = Left channel
> Measurement channel = Right channel
> Mute all drivers except L-TW and R-TW
> Measure (label as R-TW)
> Mute all drivers except L-TW and R-MR
> Measure (label as R-MR)
> Mute all drivers except L-TW and R-W
> Measure (label as R-W)
> Save and Post these 3 measurements as an mdat file for analysis.

[Step 3. will set the new calculate delays based on Step 2 and then remeasure using the Step 2 series measurement plan to confirm the final settings. This concludes the XO timing phase of the setup.]

Questions?
 
#31 ·
Step 2.1

It seems like the left mid is around 2.5ms slower and the left woofer is around 6ms slower then the right tweeter and left tweeter.

However, If you look at the group delay for the left channel as a whole, it seems like the FR phase is really good and smooth. So should I disregard the phase response smoothness or just concentrate on the timing.

Thanks! You have been a great help in helping me understand TA and improving my sound.
 

Attachments

#32 ·
I intended that Step 2 be completed in it's entirety before analysis. In this car application I expect that a compromise L Vs R timing alignment may be needed due the disparate geometry. That can't be evaluated though until both channels data are available. I did an analysis of the left channel anyway to determine the best driver timing. This left channel timing may need to be changed a little when the right channel data is available. Without the current driver delays that I requested I can only offer the adjustments needed from the current settings. Since we are only adding delay in this case, this shouldn't be a point of confusion.

Recommended Delay Adjustments:
  • L-TW = None [retain current delay and polarity setting]
  • L-MR = +0.12 ms, Invert [increase the delay and invert the polarity]
  • L-W = +0.60 ms [increase the delay and retain the current polarity]

These recommended changes provides the best phase tracking and SPL support possible for this setup.

Comments:
The current TW/MR XO is timed very well. It is the 2nd best timing alignment and would perform as well for SPL support and phase tracking. The MR impulse is leading the TW impulse however by approximately 1/2 wavelength. The recommended alignment is the more conventional alignment with the initial rise of the impulse of both the TW and MR being close to the same time. To do that the MR was inverted and delayed by approximately 1/2 wavelength.

The current MR/W XO timing is also very good; almost ideal. However the relative polarity between the 2 drivers is wrong so they are working against each other causing a significant dip in the SPL response. The recommended setting has the correct relative polarity between the 2 drivers due to the MR being reversed. The delay adjustment on the L-W was already good, but the minor recommended change makes it a little better.

Selected charts:

SPL support in the 2 XO ranges.
Text Line Green Diagram Plot


Comparison of the current SPL response to the recommended settings.
Text Green Line Font Blue


Note, the L-W SPL level was reduced in this analysis for clarity. The phase tracking and effective SPL support will be retained no matter the final driver levels chosen.
 
#33 ·
Ok.The whole Step 2. I made some TA adjustment to the Left Mid as per your earlier mail. But ran out of delay for my Left Woofer. I believe then instead of adding .6ms to my left woofer, I should just add .6ms delay to all my other 5 drivers?

This is currently my TA for my 3 way active. Right Hand Drive so driver in on the Right side.

L-T = 0.67ms
L-M = 0.42ms
L-W = 0ms

R-T = 2.17ms
R-M = 1.67ms
R-W = 0.83ms

I seem to get a worse Group Delay with more spikes with the inverted Mids as you suggested. Could you let me know how you deduced from my measurements that my mids or earlier Tweeter was inverted?
 

Attachments

#34 ·
I made some TA adjustment to the Left Mid as per your earlier mail. But ran out of delay for my Left Woofer. I believe then instead of adding .6ms to my left woofer, I should just add .6ms delay to all my other 5 drivers?
No, we would reduce the delay on the other 5 drivers.

This is currently my TA for my 3 way active.
Thanks for the new current delay settings. I will use these for this analysis.

Right Hand Drive so driver in on the Right side.
I find it hard to reach over there to operate the steering wheel and peddles. :bigsmile:

I seem to get a worse Group Delay with more spikes with the inverted Mids as you suggested.
Reversing the polarity of a driver will have no impact on group delay or the number of spikes in its bandpass range. It just shifts the phase by 180°. The driver delay changes will impact the group delay.

Could you let me know how you deduced from my measurements that my mids or earlier Tweeter was inverted?
By 'invert' in this context I am referring to inverting the current polarity of the Mids from the current polarity. It would have been more clear if I used; 'reverse'. The absolute polarities the drivers that works best to integrate the speaker is depended primarily on the XO filter settings employed. All professionally aligned speakers make this decision based on modeling or measurement of the system. It is very common to have drivers in the same speaker wired with opposite polarities.

The decision as to the best relative driver polarity to use for M vs T XO for instance is based on the phase relationship of the 2 drivers through the XO range. We want the 2 drivers to work together as well as possible at each frequency within the XO range. That provides the best SPL support and the most stable sound lobe at those frequencies (see wiki 'acoustic lobing'). This is best determined by analyzing the phase tracking through the XO range. We want the phase to track as closely as possible through that range. Reversing the phase of one of the drivers and adjusting the relative delay between them are the controlling factors in optimizing phase tracking.

This link shows an example of phase tracking being optimized through the XO range. Your phase tracking will be more confusing to analyze due to all the reflections. I normally post an example of the final alignment after the analysis is completed. The impact on SPL support is an indirect indicator of the phase tracking and an easier chart to understand and hence I provided the 2 charts in Post-32.
 
#35 ·
I completed the analysis.
The following table shows the adjustments to the current delay settings or both channels. The last column represents the new delay settings.
Product Auto part Suspension part


Right channel SPL support:
Text Line Green Plot Diagram


Right channel TW and MR phase tracking in the XO range.
Text Line Plot Slope Diagram


The prior left channel charts shown in Post-32 are still valid.
Like the other car applications I have seen, the heavy reflections make this type of analysis more difficult. In this case I was still able to identify the best timing alignment for the overall system. Given proper EQ to an appropriate house curve this timing should work very well.
 
#36 ·
I completed the analysis.
The following table shows the adjustments to the current delay settings or both channels. The last column represents the new delay settings.
View attachment 138754

Right channel SPL support:
View attachment 138762

Right channel TW and MR phase tracking in the XO range.
View attachment 138770

The prior left channel charts shown in Post-32 are still valid.
Like the other car applications I have seen, the heavy reflections make this type of analysis more difficult. In this case I was still able to identify the best timing alignment for the overall system. Given proper EQ to an appropriate house curve this timing should work very well.

Thanks jtalden! You have been a great help! Imaging did seem to improve up a notch. But the biggest improvement seem to be the bass which is a little more upfront/infront nearer the bonnet then below the dash. I will run the measurements again next week after I install my APL1 for FIR EQ and upload the results here.

:T:T
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top