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3 Attachment(s)
Summing at crossover - LR24db/BU24db
As a continuation from this thread i want to discuss my efforts in integrating sub to midbass and midbass to tweeters.
As my phase cohesion wasn't that good, clearly to see in the aforementioned thread by not summing of 6db in my crossover regions, i decided to start from scratch. Yes, from scratch, means EQing, level matching drivers, and then adjusting time delay from my baseline (through tapemeasure) to have better summing at the crossover.
For the speakers see my sig.
This time the crossovers were chosen as follows:
Sub: Lowpass 63Hz LR24db, Level in DSP: -4.5 db
Midbass: Highpass 63Hz LR24db, Lowpass 2500Hz LR24db, Level in DSP: left 0db, right 0db
Tweeters: Highpass 2500 LR24db. Level in DSP: left -8.5db, right -6db
DSP used: Mosconi D2 100.4 DSP (DSP amplifier).
I use a custom curve made with Justins Spreadsheet.
Results from EQing and level matching are in the following screenshot.
Attachment 11117
You can see the slopes follow the LR24db alignment almost perfectly. Almost, as there is a 0.5-1db difference in some areas.
Problem: when entering the time delay values from Erins calculator (and Jazzis, but result is the same) i only had 3db summation at all crossover points for all drivers (using a screenshot where my sub-midbass xover was at 80Hz, but result is the same between both. It's just for demonstration purposes. Sub is missing in the screenshot, but it had only 3 db of summation just like the midbass to tweeters).
Attachment 11118
Now i did the following.
I entered the initial delay values for my midbass and tweeters:
Left Tweeter: 2.31ms
Left Midbass: 1.17ms
Right Tweeter: 0.83ms
Right Midbass: 0ms
Sub: 0ms
After that i added 10ms of delay to all drivers, muted the tweeters (have to do the fine adjustment for the tweeters still) and removed delay from the subs in 0.4ms steps and measured with periodic pink noise.
At one point i had a big dip in the response. At that point i stopped and added an amount of delay that equals half a wavelength of 63Hz in time (think it was around 15.87ms, so i added half of that: 7.94ms) and then i lowered the delay of all drivers uniform until the delay on the subs was at 0ms again.
This brought me to the following time delay settings and the following summation in the sub-xover:
Left Tweeter: 13,82ms
Left Midbass: 12.64ms
Right Tweeter: 12.36ms
Right Midbass: 11.56ms
Sub: 0ms
Attachment 11119
Looks a lot better, but still missing around 1db of summation.
I haven't yet measured both midbass drivers together, nor tweeters together, as i want to get each side done first as good as i can.
Now, would you go for that last db, or would you call it a day and live with it? Is this missing 1db really due to phase or can i savely eq this by minor adjustments in the xover region?
Is my way of doing all this like i'm doing it right now valid at all?
Next on my list is the midbass/tweeter crossover integration. I'll follow up with that in another post in this thread, but right now the plan is to do it like with the subwoofer, i.e. add some delay and then substract delay from midbass and sub until i have cancellation and then flip phase on the midbass back to 0db.
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Re: Summing at crossover - LR24db/BU24db
The only time I’ve ever got a full 6db of summation is while using smaart to actually set delays and phase by a mic positioned between the ears and then adjusted the delays to suit, of I do this I can sum my front midbass and get a full 6db between them, that means they are perfectly in phase
the tape measure is off by +/- 2cm and the resulting phase mismatch causes all manner of issues through the passband of the speaker to its other side counterpart and also the higher and/or lower drivers also
seeing phase live while adjusting delays is a game changer for me for tuning
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1 Attachment(s)
Re: Summing at crossover - LR24db/BU24db
On to session two.
I muted the subs and one side midbass and tweeter and linked left and right tweeter together.
Measured in 0.2ms steps first, but not matter what, i wasn't able to get the mids and tweeters to sum up to 6db when played together.
Somewhere i read that if two drivers only sum up to 3db one of the drivers is 90° out of phase. Might this be something that only an allpass filter is able to solve?
What i managed to get though was a more uniform sum between left and right.
Attachment 11120
All in all i arrived at around 0.34ms more delay for both left and right tweeter.
Might it be the reason for not fully summing that the midbass drivers are low in the doors and the tweeters up in the A-pillars?
Maybe i should think about adding a dedicated midrange to the system. As i had the 12 speaker shaker system before i have the cutouts in the door panel already.
Overall the setup sound really good right now (to my standards at least). Drums hit hard, no harshness anywhere, guitars sound wonderfull... don't know if i should hunt the missing few decibels in the mids/highs xover for now.
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Re: Summing at crossover - LR24db/BU24db
I'll post some measurement of my graphs for comparison shortly. For what it's worth, I've found that I only get about 3dB of summation when playing my L+R 3.5" dash speakers together, but get up to 6dB summation when I play my L+R 6x9 midbass speakers together. I say "up to 6dB" because in certain areas of the midbass frequencies, I get less (and allpass filters didn't seem to change that whatsoever). I've been told that it's rare to get 6dB summation on the higher frequencies in a car (due to waveform length or something like that).
Great thread though - I think this is a great topic that often goes unlooked at by us "novices" (not sure about your experience level, but I consider myself a novice at this).
I know one thing, I must like my midbass more than most, because my midbass speakers go up on a pretty significant slope as the frequency gets lower. :-) I also overlap my midbass and "sub" (just a small 8" underseat powered sub). Graphs coming shortly...
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1 Attachment(s)
Re: Summing at crossover - LR24db/BU24db
Oh... i'm definitely a novice, but trying to learn (to my wifes dismay i may add).
So i had my third session today...
I guess i nailed the bass now at least that's what the measurements show me.
I used "nulling" for the bass/midbass integration and left the mid/tweet integration alone for now.
Lowered the delays all around for mids and tweets though. Looks like they were a bit too high.
Attachment 11121
Tweeters will still follow. Tried a short round of nulling for them, but the dip was really hard to see in the graph.
Used bandwith limited periodic pink noise to find the null.
The sweeps afterwards showed that the Macbook Pro i use for tuning/measuring has some weird frequency response on it's headphone jack.
When using the tone generator the results were different from the periodic pink noise (same settings exported from REW) that i played via CarPlay.
So i stick to the ppn from my phone when doing frequency measurements and switch to the Macbook only for nulling/impulse responses and stuff.
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Re: Summing at crossover - LR24db/BU24db
For what it's worth, here is where I'm currently at after replacing my dash and door speakers. I now have Illusion Audio C3CX 3.5" coaxials in the dash and CDT Audio CL-69S 6x9" midbass speakers in the doors. Sub is just a JBL BassPro SL under-seat powered sub. Crossing over door/dash speakers at 450hz. Currently have sub low-passed at 55hz and door speakers high-passed at 50hz/55hz.
FIrst pic is of all of my front speakers (L=Blue, R=Red, Combined=Purple) and sub (Yellow/ish) - as well as entire front+sub (Grey):
https://uploads.tapatalk-cdn.com/202...ae2f3440b1.jpg
Second pic is of my dash and door speakers and the response of them playing together (so you can see how the crossover sums):
https://uploads.tapatalk-cdn.com/202...8dd27cfa2d.jpg
Third pic os of my door midbass speakers and the response of them playing together (so you can see how the crossover sums):
https://uploads.tapatalk-cdn.com/202...c88b2671db.jpg
Probably not done with this tune yet, but it sounds pretty good so far. Crossovers are definitely not summing perfectly - and I definitely don't get 6dB of summing on front 3.5" dash speaekrs. Only get some 6dB summing on 6x9 door speakers. You can see how I had to "shape" the individual door speakers to get the actual shape that I wanted when they play together (individual response and combined response differ due to lack of full summing in certain areas).
Not saying any of this is "good" or "bad" - just what I'm seeing - right or wrong. :-)
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
jtrosky
I'll post some measurement of my graphs for comparison shortly. For what it's worth, I've found that I only get about 3dB of summation when playing my L+R 3.5" dash speakers together, but get up to 6dB summation when I play my L+R 6x9 midbass speakers together. I say "up to 6dB" because in certain areas of the midbass frequencies, I get less (and allpass filters didn't seem to change that whatsoever). I've been told that it's rare to get 6dB summation on the higher frequencies in a car (due to waveform length or something like that).
Great thread though - I think this is a great topic that often goes unlooked at by us "novices" (not sure about your experience level, but I consider myself a novice at this).
I know one thing, I must like my midbass more than most, because my midbass speakers go up on a pretty significant slope as the frequency gets lower. :-) I also overlap my midbass and "sub" (just a small 8" underseat powered sub). Graphs coming shortly...
All pass filters won’t work Likely because it’s a room mode, and it’s a result of the direct sound and a reflection cancelling, an all pass can’t do direct without effecting the reflection also, so the cancellation remains if that makes sense
if your dash speakers don’t sum 6db lower down then they aren’t timed correctly or you have massive reflection issues if above the dash with glass around them
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
Cathul
I use a custom curve made with Justins Spreadsheet.
Can you please share the target curve text files you are using?
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Re: Summing at crossover - LR24db/BU24db
remember, you're almost never going to get a 6db sum in the car. reflections will show up as phase discrepancies in crossover regions. Also, why delay a half wavelength when you could just flip polarity?
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1 Attachment(s)
Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
Justin Zazzi
Can you please share the target curve text files you are using?
Sure...Attachment 11161
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
Cathul
Well, looks like those were created correctly.
The three individual files also sum together correctly to the overall target.
If you use the tape measure method for time alignment then it should work out nicely.
I can only imagine you're doing something in REW or in your processor that you don't realize.
Can you upload the REW save file so we can have a look?
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
SkizeR
remember, you're almost never going to get a 6db sum in the car. reflections will show up as phase discrepancies in crossover regions. Also, why delay a half wavelength when you could just flip polarity?
Good question.
I don't know if this is true, but i've read that to have the bass and midbass in phase in the crossoverregion and account for the 360° phase shift due to LR24db (180° forward on highpass, 180° lag on lowpass) you have to add a wavelength of delay in addition to the calculated delay from distance.
One wavelength at 63Hz is around 15.8ms, so larger than the max delay i can use. So i thought it would be a good idea to add halve a wavelength of additional delay to account for the additional delay caused by the crossover and flip the polarity to get back in phase again.
If you say "screw that" i'll remove it and flip phase back to where it was.
Edit: one thing i just remembered and that bugs me now is that when i only use the calculated delays i have a deep null at the crossover. I think i have to check the polarity of the speakers again.
Also looked at the setup that the installer did after the physical installation of the equipment. He did use Butterworth 12db slopes all around with almost no eq and no polarity flip on any speakers, but some weird delay settings. Maybe instead of flipping delay as needed he just added delay until the speakers summed up.
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1 Attachment(s)
Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
Justin Zazzi
Can you upload the REW save file so we can have a look?
Sure thing... :)Attachment 11162
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
dumdum
All pass filters won’t work Likely because it’s a room mode, and it’s a result of the direct sound and a reflection cancelling, an all pass can’t do direct without effecting the reflection also, so the cancellation remains if that makes sense
if your dash speakers don’t sum 6db lower down then they aren’t timed correctly or you have massive reflection issues if above the dash with glass around them
Ok, I'm a little confused here. Earlier in this thread, you said this:
"The only time I’ve ever got a full 6db of summation is while using smaart to actually set delays and phase by a mic positioned between the ears and then adjusted the delays to suit, of I do this I can sum my front midbass and get a full 6db between them, that means they are perfectly in phase"
But now you are saying that I actually *should* be getting 6dB of summation with my dash speakers - at least "lower down" - and if I don't, then something is wrong. :-) Obviously, I'm not using smaart, so it sounds like I really *won't* be getting 6dB of summation after all.... ?
I've had multiple people tell me that 3dB to 4dB of summation for my dash speakers is actually pretty normal and has something to do with the wavelengths and the size of the car interior - or something along those lines. I've measured, re-measured and re-re-measured the distances to my dash speakers, so I know they are correct. I'm sure that there most certainly are reflections with the dash speakers since they in stock locations and point pretty much straight up into the windshield.
But what I'm trying to clarify is the 6dB summation part. From everything I've read, you'll rarely get a full 6dB of summation - especially for mid/high frequencies - and that you can sometimes get close to a full 6dB of summation with midbass frequencies (which I do get, for the most part).
Just trying to get clarification.
I'm curious to see what kind of summation @Cathul gets when he measures L+R speaker pairs.
Thank you.
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
jtrosky
Ok, I'm a little confused here. Earlier in this thread, you said this:
"The only time I’ve ever got a full 6db of summation is while using smaart to actually set delays and phase by a mic positioned between the ears and then adjusted the delays to suit, of I do this I can sum my front midbass and get a full 6db between them, that means they are perfectly in phase"
But now you are saying that I actually *should* be getting 6dB of summation with my dash speakers - at least "lower down" - and if I don't, then something is wrong. :-) Obviously, I'm not using smaart, so it sounds like I really *won't* be getting 6dB of summation after all.... ?
I've had multiple people tell me that 3dB to 4dB of summation for my dash speakers is actually pretty normal and has something to do with the wavelengths and the size of the car interior - or something along those lines. I've measured, re-measured and re-re-measured the distances to my dash speakers, so I know they are correct. I'm sure that there most certainly are reflections with the dash speakers since they in stock locations and point pretty much straight up into the windshield.
But what I'm trying to clarify is the 6dB summation part. From everything I've read, you'll rarely get a full 6dB of summation - especially for mid/high frequencies - and that you can sometimes get close to a full 6dB of summation with midbass frequencies (which I do get, for the most part).
Just trying to get clarification.
I'm curious to see what kind of summation @Cathul gets when he measures L+R speaker pairs.
Thank you.
Smaart enables you to see live phase traces and set delays very accurately, and note what I said about the lower midrange and 6db of summation, upper midrange and treble as you say you are lucky to get 3-4db of summation
smaart is relatively new to me, so when I say the only time... it’s because it’s the only tune I’ve actually concentrated on it, I’ve not tried phase aligning mids and then summing them also, it should give a good amount of summation though... I will check the laptop later and see if I have any graphs I can utilise 👍🏼
dash speakers play into the 500hz region so I would consider it a win if I got 6db of summation at the bottom end of there register, that means reflections not withholding the bottom end at least is in phase... as you get higher the wavelengths are indeed shorter and so it’s far harder to measure them and get good phase traces, it’s far better to measure around the ears and check for the best summation at the crossover points As the brain is far less phase dependant at higher frequencys
i am about to make new a pillars and have a dashboard back for the first time in ages so I will be measuring lots of times in both smart and rew perhaps (rew has some greater functionality when it comes to averaging two measurements which smaart does have, but I’ve worked with rew for ages and i feel far more confident playing with it), I will doubtless post up lots of measurements so I will endeavour to share them in here as well as my build thread :)
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1 Attachment(s)
Re: Summing at crossover - LR24db/BU24db
I’ve just had a look and I do have a trace that illustrates 6db of summation...
it also shows a phase issue at 350 which I’ve moved to the centre of the phase trace view and the resulting dip in the response where summation sucks ass
i don’t unfortunately have the other sides response at the same input level as I adjusted the mic input for other traces, but you can clearly see I get 6db of summation at a fair few places (the reason I appear to get a little more in some places and less in others is the responses don’t perfectly match due to a static mic, but the midbass do match pretty well as a static mic is effective at those frequencys
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
jtrosky
I'm curious to see what kind of summation @Cathul gets when he measures L+R speaker pairs.
Thank you.
Up to 6db in Bass/Midbass and up to 3db for left+right in midrange/tweeters... So exactly like you.
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Re: Summing at crossover - LR24db/BU24db
I actually had a look on rew after I posted the phase trace above and I found the below...
I do get 6db through my mids in bunches with 3-4 between and the old phase issue where I get 1, but a good sign is getting at least 6db in a fair few places, if not you perhaps need to reposition drivers to make the summation better (I’ve been through 20 odd locations and aimings on top of my dash before settling on where my mids are now to get individual sides as good as they are now :pout:)
it’s not a nice task and I get that most can’t do what I’ve done (in the sense of cutting the top off a dash board and trying loads of places! Not I’m some kind of special... well I am special... but not like that lol), but sometimes it’s only 2-3” away from the screen or a different aim that can transform a stage from average to excellent 👍🏼
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Re: Summing at crossover - LR24db/BU24db
Well, my last measurement from left and right was before i redid the time delay, so i have to remeasure anyway... will do that in the next days.
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1 Attachment(s)
Re: Summing at crossover - LR24db/BU24db
5-6db from 150, phase issue at 350 the good summation after that, then a mixed bag of 3-4 after that 👍🏼 At the top end it gets hard with a moving mic to see how the summation goes, but the lower registers sub 5-700 are good to test even with mids for how well your drivers are phase aligned, that’s 1/48th octave with zero smoothing...
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Re: Summing at crossover - LR24db/BU24db
That’s a bit easier to read with 1/12 smoothing
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2 Attachment(s)
Re: Summing at crossover - LR24db/BU24db
Have done time alignment with impulse responses now. Distance measurements weren't that far off.
Had to add some delay to get a deep null in the sub/midbass xover and then flipped polarity. Let the TA for the sub at 0.
I think the installer wired the sub backwards, therefor the polarity flip. If i added 7.9ms to the delay on midbass/tweeters i had good summing with no polarity flip anywhere.
But for whatever reason i cannot get the midbass/tweeters to sum up fully, but as someone mentioned it might be hard to get a full summation in that area.
See for yourself.
Attachment 11303
And this is the total response left+right. Good summing in bass, but not so good in midrange/tweeters.
Attachment 11304
Center image is strong. When listening there is nothing wrong tonally.
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
Cathul
Have done time alignment with impulse responses now. Distance measurements weren't that far off.
Had to add some delay to get a deep null in the sub/midbass xover and then flipped polarity. Let the TA for the sub at 0.
I think the installer wired the sub backwards, therefor the polarity flip. If i added 7.9ms to the delay on midbass/tweeters i had good summing with no polarity flip anywhere.
But for whatever reason i cannot get the midbass/tweeters to sum up fully, but as someone mentioned it might be hard to get a full summation in that area.
See for yourself.
Attachment 11303
And this is the total response left+right. Good summing in bass, but not so good in midrange/tweeters.
Attachment 11304
Center image is strong. When listening there is nothing wrong tonally.
you may also which to try looking with 1/48 octave as you may see more detail about dips and peaks, smoothing makes a response look artificially better, so what you think is the level may actually be 2db off for example...
if you smooth a 1/48 octave response to 1/3 it can look like a straight line, taking it to an extreme if you have a wave like pattern of measured response with equal peaks and dips of 3db each you could smooth it to flat, now if the opposite side response had the exact opposite peaks and dips and you smoothed that to 1/3 octave and it looked flat if you then played the two together you would then get zero summation by looking with 1/3 octave smoothing, but with more detail in 1/48th octave you would see that dips cancelled peaks and peaks cancelled dips
sonetimes we have to look a bit deeper to find what’s actually happening, I will always measure in 1/48 octave and apply smoothing post measurement, that way you always get the bigger picture if you see what I mean
you will often get peaks and dips that are in differing frequencys on opposite sides of the car so it’s very reasonable to dummies this may be why you don’t get 6db of summation
i hope that makes sense 👍🏼
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2 Attachment(s)
Re: Summing at crossover - LR24db/BU24db
Yes, it makes sense, but, i'm talking about summation on left side midbass and left side tweeter crossover, and right side midbass and right side tweeter crossover, not summation of left and right together.
I checked polarity and couldn't find anything wrong with polarity (checked with speaker pop app on my iphone).
Here in 1/48 smoothing.
Right side:
Attachment 11305
and left side:
Attachment 11306
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
dumdum
I’ve just had a look and I do have a trace that illustrates 6db of summation...
it also shows a phase issue at 350 which I’ve moved to the centre of the phase trace view and the resulting dip in the response where summation sucks ass
i don’t unfortunately have the other sides response at the same input level as I adjusted the mic input for other traces, but you can clearly see I get 6db of summation at a fair few places (the reason I appear to get a little more in some places and less in others is the responses don’t perfectly match due to a static mic, but the midbass do match pretty well as a static mic is effective at those frequencys
If possible, it would be awesome if you could share your process on how to measure phase in SMAART. I am COMPLETELY new to it but would love to learn more and compare to what I’m seeing in REW. Any tutorials you found helpful?
Thanks!
Sent from my iPhone using Tapatalk
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Re: Summing at crossover - LR24db/BU24db
Ok, I think i got the reasons for subpar summing between midbass and tweeters.
1. i have a sharp dip of about 4-5db on both midbass drivers around 2500 Hz (and have my crossover set there).
2. below the dip in the midbass i have dips on the tweeter, mainly between 2000 and 2500 Hz of about 2-3db.
3. something is wrong with polarity.
Regarding point nr. 3: before my last remeasure i had to flip polarity on the subwoofer to get good summing from sub to midbass. Without that i have a sharp dip right at the crossover.
When i flip the sub back to normal polarity and flip the midbass instead i again have good summing from sub to midbass and better summing from midbass to tweeter as compared to normal polarity for midbass and tweeter.
Anyway... the dips are not responding to EQ at all, so i guess I have to live with that for now until i decide to upgrade the fronts from 2-way to 3-way with a dedicated midrange and higher crossover between mids and tweeters.
Only thing that puzzles me is the polarity issue. I measured polarity with a speaker pop before time aligning and eqing the drivers and got a positive on all speakers, but apparently this is wrong.
Or is there any other explanation for that? Delay settings are in the range of the measured distances plus minus a few centimeters.
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
mauian
If possible, it would be awesome if you could share your process on how to measure phase in SMAART. I am COMPLETELY new to it but would love to learn more and compare to what I’m seeing in REW. Any tutorials you found helpful?
Thanks!
Sent from my iPhone using Tapatalk
nathan lively... sound design... look him up on you tube, everything I know I e picked up from him and his videos, he covers everything from interfaces to first measurements to simple stuff, some formulas and a few simple demonstrations, he’s a cool kid... didn’t even mind when I dropped him an email about one of his formulas being incorrect, we had a bit of a chinwag
the nice thing about it is you can see phase issues and then dial in crossovers to avoid them as much as possible, it also shows up reasons why summation doesn’t happen fully or at all... see my previously posted screen shot as a demonstration
i tend to use 1/12 smoothing in phase plots and 1/12 on magnitude plots also
once you get the hang of it it really is a game changer for getting sub to midbass to midrange all in phase and timed to perfection (I use a static mic for below 300hz and timing above that frequency)
it’s a very nice setup, I use an m-audio usb mobile pre and a Dayton mic which needs a 48v phantom power preamp the model escapes me, but it’s relatively cheap and the audio interface was £35 second hand incase I didn’t get on with it
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
Cathul
Ok, I think i got the reasons for subpar summing between midbass and tweeters.
1. i have a sharp dip of about 4-5db on both midbass drivers around 2500 Hz (and have my crossover set there).
2. below the dip in the midbass i have dips on the tweeter, mainly between 2000 and 2500 Hz of about 2-3db.
3. something is wrong with polarity.
Regarding point nr. 3: before my last remeasure i had to flip polarity on the subwoofer to get good summing from sub to midbass. Without that i have a sharp dip right at the crossover.
When i flip the sub back to normal polarity and flip the midbass instead i again have good summing from sub to midbass and better summing from midbass to tweeter as compared to normal polarity for midbass and tweeter.
Anyway... the dips are not responding to EQ at all, so i guess I have to live with that for now until i decide to upgrade the fronts from 2-way to 3-way with a dedicated midrange and higher crossover between mids and tweeters.
Only thing that puzzles me is the polarity issue. I measured polarity with a speaker pop before time aligning and eqing the drivers and got a positive on all speakers, but apparently this is wrong.
Or is there any other explanation for that? Delay settings are in the range of the measured distances plus minus a few centimeters.
The actual phase of each driver isn’t as important as sometimes you will need to be reversing the phase on some drivers, for example in my pic above I have my midbass out of phase and the time alignment at some odd settings, there are always at least two ways to align drivers, and one definitely doesn’t follow a tape measure
the nathan lively video about satlive I think it is explains about the delay finder and how it sometimes works out a polarity inversion and a different delay can make the summation better than a simple distance measurement... if I can lay hands on it I will post it up, it won’t nesc be relevant if you don’t have the facility to measure phase but it illustrates how we don’t always end up with settings that are immediately obvious and they work also
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Re: Summing at crossover - LR24db/BU24db
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Re: Summing at crossover - LR24db/BU24db
And this is the one where he has two options for a polarity inversion and more delay or less delay without a phase inversion I was referring to... I would recommend watching the whole lot of videos as a learning tool, it is easier if you can play and test stuff, but you will get the idea about this powerful tool and what info it gives
https://www.youtube.com/playlist?lis...vaN7W4sl2DGTCl
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
dumdum
And this is the one where he has two options for a polarity inversion and more delay or less delay without a phase inversion I was referring to... I would recommend watching the whole lot of videos as a learning tool, it is easier if you can play and test stuff, but you will get the idea about this powerful tool and what info it gives
https://www.youtube.com/playlist?lis...vaN7W4sl2DGTCl
Awesome. Thanks for sharing
Sent from my iPhone using Tapatalk
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1 Attachment(s)
Re: Summing at crossover - LR24db/BU24db
Those links to the videos about the Smaart software are really good, but unfortunately out of reach for me right now.
Remeasured system today again while shifting the acoustical xover bass to midbass up to 80 Hz from 63Hz before.
Better bass integration this way, but still have to flip the phase/polarity on the midbass to get a good summing (around 5db) between subs and midbass and decent (up to 4db) summing between midbass and tweeters.
Checked delay again with both tape measure and impulse responses and they are good as far as i can tell.
brown is left, green is right side with 1/12th octave smoothing.
Attachment 11330
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Re: Summing at crossover - LR24db/BU24db
I just had the opportunity to use smaart on my truck last night...all I can say is wow...I have never had a better sounding system. My EQ part was done, but getting the phase to line up between crossovers and speaker pairs made such a huge difference. There is now no more guess work on if each speaker is phase aligned to the best it can be..it is.
It took a little more work than anticipated after discovering my calibrated dayton umm-6 microphone seems to have an issue that needs more investigating to make sure it is the microphone and not the computer...but I am doubtful it is the computer. I was always having an issue with my door speakers and not getting them to play much below 100hz...well when measured last night with different microphones my door speakers were suprisingly fairly flat down to 20hz (peerless sls 6")...clearly I have some microphone issue...With that discovery of the microphone issue, it made more sense why my phase was off as much as it was...at least to me.
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Re: Summing at crossover - LR24db/BU24db
I believe that, but unfortunately i only have an USB mic (UMIK-1) and cannot spend that amount of money on new equipment and software only to measure my own system. SMAART is around 1000,-- € over here plus a new soundcard, mic and all the cabling.
If only i could find a hint or manual on how to do that with REW and an USB microphone. All the tutorials and videos i found didn't help in that regard... :(
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
Jdunk54nl
I just had the opportunity to use smaart on my truck last night...all I can say is wow...I have never had a better sounding system. My EQ part was done, but getting the phase to line up between crossovers and speaker pairs made such a huge difference. There is now no more guess work on if each speaker is phase aligned to the best it can be..it is.
It took a little more work than anticipated after discovering my calibrated dayton umm-6 microphone seems to have an issue that needs more investigating to make sure it is the microphone and not the computer...but I am doubtful it is the computer. I was always having an issue with my door speakers and not getting them to play much below 100hz...well when measured last night with different microphones my door speakers were suprisingly fairly flat down to 20hz (peerless sls 6")...clearly I have some microphone issue...With that discovery of the microphone issue, it made more sense why my phase was off as much as it was...at least to me.
it is a game changer, matching side to side and between sub, midbass and mids is awesome, it does indeed change how you hear (or don’t I find) the stereo as a whole
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Re: Summing at crossover - LR24db/BU24db
Doesn't the Dirac Live system handle all of this phase-related stuff for you automatically? As much as I like my Helix, I'm really starting to wonder if I should have just went with a MiniDSP DiracLive-enabled DSP. :-) Let it handle this kind of stuff. Unfortunately, the Smaart system is just too expensive for most DIY'ers - especially if a DiracLive-enabled MiniDSP (which is less expensive) will handle all of this for you automatically - and includes the DSP hardware as well. :-)
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Re: Summing at crossover - LR24db/BU24db
I was able to progress a bit more in my most recent tune and I can confirm that the method for evaluating and fixing phase issues between drivers that Skiz outlined 100% works and is awesome. (Obviously a lot of you already knew that but I wanted to show my results as an example for those that are working through it)
I found that my wideband and mid bass were out of phase on the left side (with a big negative cancellation in the crossover region) and a simple flip of polarity of the mid bass fixed it.
My sub was a bit more challenging. I have it downfiring now (thanks to one of Erin’s videos where afterwards I verified in REW that my sub had better output when downfiring) and tried my best to measure to the voicecoil for time alignment but something was a bit off still. The summation was only ~3 dB across the crossover. I thought about trying an all pass filter but I honestly don’t know how best to use those yet so I tried sliding the phase slider in the helix processor and landed at a setting of 50 degrees where when I measured I got an almost perfect 6 dB rise at the crossover with seemingly no ill effects elsewhere.
The imaging of the bass upfront is the best it’s ever been. Skiz’s video was indeed a two for one as getting this right helps so much in that regard.
Below are my measurements of the right and left individual drivers, sub, and the R and L sides each playing with the sub all together. The crossover region with my wideband and mid bass is summing nicely to ~6 dB as well.
My measurements are dropping off a bit more than my target curve above 6 kHz but I like the way it’s sounding.
My setup is an active 2-way with Audiofrog GS25 and Peerless SLS 6.5” up front and a JL 10TW3 for a sub.
https://uploads.tapatalk-cdn.com/202...6772c59a03.jpg
Still interested in learning SMAART however. If any of you can post some of your tips on using it that would be awesome...perhaps in a different thread.
Sent from my iPhone using Tapatalk
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
jtrosky
Doesn't the Dirac Live system handle all of this phase-related stuff for you automatically? As much as I like my Helix, I'm really starting to wonder if I should have just went with a MiniDSP DiracLive-enabled DSP. :-) Let it handle this kind of stuff. Unfortunately, the Smaart system is just too expensive for most DIY'ers - especially if a DiracLive-enabled MiniDSP (which is less expensive) will handle all of this for you automatically - and includes the DSP hardware as well. :-)
As far as I know you still need to setup crossovers and time alignment (That’s what smaart helps you to do with ease for mids, midbass and subs), the Dirac live can correct phase and response to a degree, but what it can’t do is fix install related phase issues with reflections, as any correction is applied to the direct and the reflected sound so the net result is still a phase issue that you can hear
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Re: Summing at crossover - LR24db/BU24db
In the past few days i tried a lot of things to get a better summing at the crossover between midbass and tweeter.
Acoustical crossover is at 2300 Hz.
I tried nulling with phase switching, impulse response and "brute force" by going 0.4ms (should be a bit more than one full cycle on the tweeters and a xover frequency at 2300Hz) up and down in the smallest steps possible with the Mosconi D2 100.4 DSP amplifier (0.02ms) from the calculated time delay values from Jazzis spreadsheet after measuring the distance again from the tip of the microphone to each speaker. After measuring i checked the polarity of the drivers with a polarity checker. Polarity was uniform on all drivers.
Never, not even once was i able to get a 6db sum on either side between midbass and tweeter. Most i could get were the current 4db i have right now.
Now i start wondering if adding a dedicated midrange would help me as the midrange is much nearer to the tweeter than the midbass.
Current locations of the drivers in my S550 Mustang are the original locations midbass down low in the doors and tweeters in the stock A-pillar location.
Don't get me wrong. It sounds great right now. Very good staging, strong bass/midbass integration and overall sound, but the missing 2db really nug me.
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Re: Summing at crossover - LR24db/BU24db
Quote:
Originally Posted by
Cathul
In the past few days i tried a lot of things to get a better summing at the crossover between midbass and tweeter.
Acoustical crossover is at 2300 Hz.
I tried nulling with phase switching, impulse response and "brute force" by going 0.4ms (should be a bit more than one full cycle on the tweeters and a xover frequency at 2300Hz) up and down in the smallest steps possible with the Mosconi D2 100.4 DSP amplifier (0.02ms) from the calculated time delay values from Jazzis spreadsheet after measuring the distance again from the tip of the microphone to each speaker. After measuring i checked the polarity of the drivers with a polarity checker. Polarity was uniform on all drivers.
Never, not even once was i able to get a 6db sum on either side between midbass and tweeter. Most i could get were the current 4db i have right now.
Now i start wondering if adding a dedicated midrange would help me as the midrange is much nearer to the tweeter than the midbass.
Current locations of the drivers in my S550 Mustang are the original locations midbass down low in the doors and tweeters in the stock A-pillar location.
Don't get me wrong. It sounds great right now. Very good staging, strong bass/midbass integration and overall sound, but the missing 2db really nug me.
polarity of drivers with a pop checking method doesn’t mean the sound they produce will be in phase with other drivers through the crossovers, for example mine are connected electrical in phase, however I then flip the phase on midbass and tweeters even though I’m using measured 24db slopes to get them to sum as best as I can
i get why you’d do it on a new install as a check, but after that point it bears little relation to actual phase in a vehicle if that makes sense... I’ve seen you say you’ve measured it a few times, but that is not important unless you are trouble shooting... in theory it’s good... but in practice it’s not really relevant if you would