Author Topic: Optimizing your speakers - taming the crossover and phase  (Read 9240 times)

Offline desray

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Preamble
This is a follow-up to my Audyssey’s thread which I have shared my knowledge and experience in getting the best out of Audyssey calibration. I have been struggling to come up with the next tutorial in HT calibration but due to work commitment last year, I have procrastinate to the extent that the whole idea just die of “natural death”…but the recent queries on how to get the crossover settings right for the speakers give me a “wake-up” call and so I guess its time for me to get into my “sharing” mode one more time.

Before I proceed any further, pls take note that the steps shown in this tutorial are gathered from various “reputable” AV websites over the years. Some of the steps listed maybe familiar to some of the members here. So this is for the benefit of those bros whom have just joined the Home Theater clan who wish to “optimized” their sound “investment”. I have put into simple terms for what I have learned and practise over the years. For those who know me will understand that whatever whenever I put up a tutorial of some sort, it is based entirely on my personal experience going through the process. So rest assured that you will get satisfactory results if you follow it. Of course I do understand that it can he hard to comprehend based on words...but I promise to make it as plain simple as possible for all.

Pre-requisites
As mentioned, this is actually the 2nd phase of calibration. I am assuming that you have completed the Audyssey calibration. And now you are moving into the 2nd phase to optimize your speakers.



Finding the right crossover settings
If you have just completed your Audyssey setting, now is the time for you to check the “crossover” values provided by the AV Receiver during the Audyssey calibration (1st phase). To do that, you will need to do some “homework”. Now is the time for you to read up the user guide of your speakers. Inside the guide/setup, you should be able to get the Frequency Response/Range readings. Some of the speaker manufacturers will give a different description such as Filtered Frequency Response etc. But fret not, the terms are the same. Of course, you can also “google” (search the internet) for the technical specs of your speakers and subwoofer(s). For demonstration, I will use my existing HT speaker setup as an example to guide you through…
Here’s an overview of my 13.2 speaker setup.

Frequency Response of my speakers:
Atmos-enabled speakers (x2): KEF R50 - 96Hz – 19.5kHz
Mains: KEF R100 - 49Hz - 45kHz
Center: KEF R200C - 52Hz - 45kHz
Surrounds: Mirage Omni 50Hz - 55Hz - 20KHz
Surround Backs: Mirage Omni FX - 80Hz to 20kHz
Wides: Dali Concept 1 - 62.5Hz - 22.5KHz
JL Audio E112 (Subwoofer) - 22Hz - 118Hz
JL Audio E110 (Subwoofer) - 25Hz - 116Hz



Now that you know the Frequency Response (factory) range and also the post-Audyssey crossover values. We are going to find out what I would call the “allowable” crossover range that you can set under the “Manual” crossover setting in your AVR. The general rule of thumb in determining the highest to the lowest crossover range can be derived from the highest frequency that your Subwoofer allows and the lowest frequency that your speaker allows. Take my main speakers (KEF R100) as an example. The speaker frequency response is set at 49Hz - 45kHz (or 45,000Hz). This tells me that the lowest frequency for these main speakers are 49Hz. Now that we have the “lowest” frequency range determined, we then look at the highest frequency of the my 2 JL Audio subwoofers. Some differences as you can see:

JL Audio E112 (Subwoofer) - 22Hz - 118Hz



JL Audio E110 (Subwoofer) - 25Hz - 116Hz



Since there is little to no value of using “118Hz” and “116Hz” for the frequency range. I simply round it off to the nearest whole number which in this case are “120Hz” for both my JL Audio subwoofers. Besides, my Denon X7200WA doesn’t allow “custom” crossover value to be set.

If we take a look at the JL Audio official website, you will find there is another set of frequency response numbers called, “Filtered Frequency Response” which have a value of 22Hz – 130Hz. You can either choose 120Hz or 130Hz in this case to be the “highest” crossover range. Now we have an “allowable” range of crossover values for my KEF R200C (center speaker) – i.e. Between 50Hz – 120/130Hz. What it means is that you are “safe” to set any crossover values between 50Hz all the way up to 130Hz. You can experiment with 50Hz, 60Hz, 70Hz, 80Hz (THX), 90Hz, 100Hz so on and forth…I set my KEF R100 at 80Hz in this case as I it sounded the “cleanest” to my ears. Yes, you need to play some of your favourite tunes/music (preferably with good amount of bass) to determine that.

IMPT NOTE:
DO NOT lower the crossover value of a speaker if you intend to use Audyssey for the best movie experience. If you attempt to set a lower crossover value than the one determined by the Audyssey after the calibration had completed, you will inevitably create a “hole/gap” in that “frequency range” that will be omitted by Audyssey to fill in the “info” in that frequency range and that will affect the Dynamic EQ (DEQ) to perform below par. Hence, you will not want to do that! Again using my center speaker as an example, I cannot set a lower crossover value of less than 110Hz (e.g. 90Hz) for the reasons stated above. I can, however increase the crossover value to say 120Hz or a maximum of 130Hz (highest allowable crossover range).
With that in mind, I can now proceed to set my crossover values for the other speakers with confidence.
 
Allowable Crossover range for the speaker setup:



As you can see, Audyssey did quite a pretty “good” job in determining the crossover value for the speakers except for my KEF R100 speakers which it set at 40Hz while the lowest frequency range “allowable” starts from 50Hz and above…
« Last Edit: October 03, 2017, 17:34 by desray »

Offline desray

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #1 on: January 24, 2016, 19:24 »
Now that you have determined the “allowable” crossover range for your speakers. You are now ready to take it to the next step – i.e. to refine it further! This will entail fiddling with the phase control to get the “maximum SPL” at your MLP and every other seats within the MLP. For this, you will need to deploy your Audyssey mic on a tripod (DO NOT be lazy, use a camera tripod) and place it at your Main Listening Position (MLP). Now google this website, “onlinetonegenerator”. Here’s a screenshot of the website.



The website is very intuitive to use, all you need is a tablet/laptop with Bluetooth connectivity. In my case, I use my iPad Pro and connect to my Denon X7200WA via Bluetooth connection. Recall that my crossover setting for the main speakers is “110Hz”. So I will type in 110 in the text field and hit the Play button. One great thing about this website is that the tone (sine wave) will continue to play for as long as you want until you hit the Stop button. Simple? Right?

SPL Meter

Next, you will need to download an iOS app called, “Sound Meter” from the Apple’s Store (free). See below for a screenshot of the app’s interface.



Connect the 3.5mm stereo jack to your phone/tablet’s stereo input and hit the Play button.

Phase Control

For dual subwoofer setup, remember to turn off one of the subwoofers as you will want to measure the SPL from one subwoofer at a time. What you need to do here is to place the phone/tablet on top of your MLP (headrest area) so that your hand or movement will not interfere with the readings. Furthermore, you will need to be mobile as you need to go to your subwoofer’s panel to make adjustments to the Phase control. Start with ‘0’ degree and take down the SPL reading. Next turn the phase control to the max – can be ‘180’ degree or even higher depending on the make and model of your subwoofer. Take a reading as well. Now do you see any “difference” in the SPL reading? If there are indeed some difference (can be as little as +/-2db), then you are required to make finer adjustments to it. To do it correctly, you will start from adjustment from ‘0’ degree on the Phase control knob and slowly work your way in a clockwise manner until you find the highest SPL reading registered on the Sound Meter app. Next, you will place the phone/tablet (still with the app running in the background) to the other adjacent seats within the MLP and take the reading. Your task is to ensure all the seats have the same SPL readings. If one of the seat has a slightly higher SPL reading than the other one, go back to your Phase control knob and continue to make finer adjustments UNTIL all seats have more or less the same SPL reading. Repeat this cycle for the 2nd subwoofer and remember to turn off the 1st subwoofer.



After you have completed adjustments for the 2 individual subwoofers, turn on the 2 subwoofers simultaneously and concurrently take all the SPL readings. Again go through the same cycle by ensuring all seats have the same SPL readings. After you have completed the phase settings, you will need to use a professional calibration disc (e.g. Spears and Munsil Calibration Disc) which allows you to check the SPL readings for the entire speaker array (i.e. 7.1 setup) to ensure that with Audyssey engaged (at Reference level) and DEQ set to ‘On’, all speakers will produce the same SPL readings.





It doesn’t matter at what Master Volume you want to set it – you can set at Reference level if you want for accuracy – i.e. ‘0’ db and bear with the intense “noise” pollution or you can set at a comfortable range of say “-10db” below Reference level to take the reading. As subwoofer reading can be quite a challenge to take (due to its omni-directional characteristics and its interaction with the room modes), the readings can hover quite drastically. The key here is to ensure that the subwoofer’s SPL reading is close to the readings of other speakers. I finally end up with the following Phase settings for my 2 JL Audio subwoofers:

JL Audio E112 (Subwoofer) - "230" degree (located in the front between my KEF R100 speakers)
JL Audio E110 (Subwoofer) - "255" degree (located diagonally to the back of my MLP)

Note: In my case, my subwoofer placement is fine but I am not satisfied with my subwoofer distance. Always remember when you have a dual subwoofer implementation, it will be considered good practice to place the 2 subwoofers at equidistant from each other as far as possible. This is easier to implement if you co-locate or place the 2 subwoofers in the front left and right. In my case, I chose to place my 2 subwoofers diagonally across each other (one in front and the other at the rear). This had posed a challenge for me since the MLP should be at a 70:30 or 60:40 ratio. The subwoofer at my rear will always be nearer to my MLP while the front is slightly farther away. Well, we just have to let Audyssey take over from here...

The final thing to do now is to do a 20Hz – 200Hz sine tone sweep to ensure that you get a smooth tone sweep between the main speakers and the subwoofers. Choose the one where it is located nearest to your main speakers. Make sure that you set the AVR to DIRECT or STEREO mode when doing this. If done correctly, your main speakers will blend in seamlessly with the subwoofer when the sweep tone is performed. Increase the Master volume if you have a hard time hearing it. If you are convinced that it is not well done. Repeat the whole cycle again.

Note: You can increase the “combined” subwoofer readings in the Manual “Level” settings to say +3db to get the “oomph” you are looking for…this apply to those who wanted a more aggressive house curve. YMMV…its optional. For me, I did increase my subwoofer levels to +3db.

Once you satisfied with the adjustments made. You can replay your favourite tunes/music again to test drive the tracks and see if you like it. I know I do…now its your turn to try out!  :D
« Last Edit: January 24, 2016, 19:41 by desray »

Offline Jag

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #2 on: January 24, 2016, 20:09 »
+1.

I wouldn't have that much energy to write such articles anymore. Kudos Desray.
ATMOS and Auro ready! 15 surr spkrs . Time to optimize

Offline desray

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #3 on: March 11, 2016, 11:55 »
Requests from members to make this topic sticky. Here goes...


Offline talltist84

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #4 on: November 19, 2016, 16:23 »
Not quite sure on the setup part for phase control.

Do we plug the audessy to the ipad or to the receiver?

I understand that we have to connect the ipad to the receiver via bluetooth, hence when we press play on the online tone generator website (ipad), does the sound come out from the phone or the speakers now (noting that we connect to the receiver via bluetooth)?

Quite confused on this.

Offline desray

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #5 on: November 19, 2016, 19:52 »
Not quite sure on the setup part for phase control.

Do we plug the audessy to the ipad or to the receiver?

I understand that we have to connect the ipad to the receiver via bluetooth, hence when we press play on the online tone generator website (ipad), does the sound come out from the phone or the speakers now (noting that we connect to the receiver via bluetooth)?

Quite confused on this.

Bluetooth link up. Sine tone will be generated from the web plugin through the front speakers. The Audyssey mic connect to your smart phone with the SPL app installed. Do the measurement.

Offline wechnivag

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #6 on: December 01, 2016, 12:39 »
Hi Desray, nice write up! 

I was thinking about your earlier comments that changing the Sub distance in the AVR after audyssey is not recommended. Based on my understanding, adjusting the phase in the Sub is basically equivalent to changing the distance, it allows the sound waves from sub and mains at the xo frequency to combine additively as much as possible (in phase) vs cancellation due to out of phase. However, I understand that the phase knob adjustment is typically centered on a certain frequency, ie it doesn't change the phase equally at 120hz vs 80hz. Changing the distance on the sub is basically a delay setting, it adjusts the phase at all frequency more evenly? At the end of the day, both methods allow a smoother xo integration between mains and sub at xo frequency by matching phase and avoiding cancellation.

In my experiments with REW, audyssey consistently does not set the phase correctly between sub and mains or center, causing a deep null at the selected XO frequency. However, for AVR with SubEQ, audyssey does set the phase between Sub 1 and sub 2 perfectly, nails it. I have found that when I adjust only sub 1 or sub 2 distance individually, I get a degradation in the combined sub FR. It skews the curve towards one vs the other, and some nulls appear. This is especially so if one of the subs cover Low bass, one covers midbass, like many end up doing, mine included. So I only adjust sub distance together by the same amount for sub 1 and sub 2.

I think sub distance also gives a slightly finer control adjustment vs the phase knob.

Appreciate your thoughts on this. Thanks!



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Offline desray

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #7 on: December 19, 2016, 23:06 »
Hi Desray, nice write up! 

I was thinking about your earlier comments that changing the Sub distance in the AVR after audyssey is not recommended. Based on my understanding, adjusting the phase in the Sub is basically equivalent to changing the distance, it allows the sound waves from sub and mains at the xo frequency to combine additively as much as possible (in phase) vs cancellation due to out of phase. However, I understand that the phase knob adjustment is typically centered on a certain frequency, ie it doesn't change the phase equally at 120hz vs 80hz. Changing the distance on the sub is basically a delay setting, it adjusts the phase at all frequency more evenly? At the end of the day, both methods allow a smoother xo integration between mains and sub at xo frequency by matching phase and avoiding cancellation.

In my experiments with REW, audyssey consistently does not set the phase correctly between sub and mains or center, causing a deep null at the selected XO frequency. However, for AVR with SubEQ, audyssey does set the phase between Sub 1 and sub 2 perfectly, nails it. I have found that when I adjust only sub 1 or sub 2 distance individually, I get a degradation in the combined sub FR. It skews the curve towards one vs the other, and some nulls appear. This is especially so if one of the subs cover Low bass, one covers midbass, like many end up doing, mine included. So I only adjust sub distance together by the same amount for sub 1 and sub 2.

I think sub distance also gives a slightly finer control adjustment vs the phase knob.

Appreciate your thoughts on this. Thanks!



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Sorry for the late reply as I didn't realise that there is a post from you in this thread.

It is NOT advisable to change the distance AFTER the Audyssey calibration UNLESS you know what you are doing - i.e. proficient in the use of REW and able to fine tune the response accordingly. For everything else covered in this tutorial, the beauty of it is anyone w/o REW background can do it with certain degree of confidence that the overall bass response will be much more smoother combined with Audyssey settings.

I need to have a listen at one of the member's place who utilise REW and/or claim to have successfully integrate the subwoofer with the mains by making adjustments to the distance of the subwoofer settings in the Manual Audyssey settings. Only then, I can tell whether both methods achieve similar results. I'm more of the hands on person and I would like to witness it myself before commenting.

Offline ronildoq

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #8 on: January 01, 2017, 22:51 »
Hi Desray, nice write up! 

I was thinking about your earlier comments that changing the Sub distance in the AVR after audyssey is not recommended. Based on my understanding, adjusting the phase in the Sub is basically equivalent to changing the distance, it allows the sound waves from sub and mains at the xo frequency to combine additively as much as possible (in phase) vs cancellation due to out of phase. However, I understand that the phase knob adjustment is typically centered on a certain frequency, ie it doesn't change the phase equally at 120hz vs 80hz. Changing the distance on the sub is basically a delay setting, it adjusts the phase at all frequency more evenly? At the end of the day, both methods allow a smoother xo integration between mains and sub at xo frequency by matching phase and avoiding cancellation.

In my experiments with REW, audyssey consistently does not set the phase correctly between sub and mains or center, causing a deep null at the selected XO frequency. However, for AVR with SubEQ, audyssey does set the phase between Sub 1 and sub 2 perfectly, nails it. I have found that when I adjust only sub 1 or sub 2 distance individually, I get a degradation in the combined sub FR. It skews the curve towards one vs the other, and some nulls appear. This is especially so if one of the subs cover Low bass, one covers midbass, like many end up doing, mine included. So I only adjust sub distance together by the same amount for sub 1 and sub 2.

I think sub distance also gives a slightly finer control adjustment vs the phase knob.

Appreciate your thoughts on this. Thanks!



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If you have the subs FR flat up to the crossover point after audy and if you measured C+subs with a dip, then adjust both the subs distance equally. This means audy got the distance right. (most of the time it does), the dip is caused by cancellation of your mains and sub.
However, if after audy your subs response is not flat up to cross over region, then u can adj one of the distance of the subs, either 1 or 2, and toggle between the two. One good method is using rew's RTA feature. you will then need to mark down distance between two subs, and try with increments or subtract by 30cm until you find the best response. finer tweak with 10cm once u know the range. The goal again is to avoid any dips, as peaks can be EQed, if you have an outboard EQ device. Very effective tweak as the goal is to get as flat up to 120hz if possible.

So if you increase distance of sub 1 by 1 meter, and sub 2 by 1 meter, there is no change in time delay for the subs, so no phase shift, and hence no change in freq response. Simply because by adding 1 meter each to both subs or subtracting 1 meter each to both subs, the avr then sends both signal at the same time. In short, if u Increase/decrease both distance of subs equally, purpose is to get a smoother response at the crossover region of the Mains+Subs.

Adjusting one of the subs distance without equal distance is to phase adj the two subs for a smoother response. Quite effective. No degration on FR, there can only be improvement. Because you can always revert to original distance if u cannot find the best response. So no harm experimenting if you have the means to measure with REW.

Enjoy bro, ive completed my journey! Very tiring but satisfying after all the hard work

psychobilly

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #9 on: September 15, 2017, 14:10 »
TS, I could be wrong though:
"Take my center speaker (KEF R100) as an example. The speaker frequency response is set at 49Hz - 45kHz (or 45,000Hz). This tells me that the lowest frequency for this Center speaker is 49Hz."

do you mean the Mains?

Offline desray

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #10 on: October 03, 2017, 17:35 »
TS, I could be wrong though:
"Take my center speaker (KEF R100) as an example. The speaker frequency response is set at 49Hz - 45kHz (or 45,000Hz). This tells me that the lowest frequency for this Center speaker is 49Hz."

do you mean the Mains?


Yes, typo error...I'm referring to Mains (KEF R100). Thanks for pointing that out.


psychobilly

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #11 on: October 20, 2017, 10:19 »
The frequency response of my speakers pre-Calibration:
Front L and R: 52hz-22khz
Center: 50hz-22khz
Surrounds: 52hz-22khz
Sub: 27hz-40/140hz
Klipsch DA speakers: no specs; specs only said conformed to Dolby Atmos specs

After Audy:
Fronts: 40hz
Center: 40hz
Surrounds: 40hz
Sub: 120hz
Klipsch DA: 120hz

Post-Audy, I changed to:
Fronts: 80
Center: 80
Surrounds: 80
Sub: 120
Klipsch DA: 120

I manually adjusted the sub level setting to +3db for added oomph. I may also alternate between 80z and 120hz to determine my preferred setting. Center speaker was also adjusted to +3db for my preference as I like the dialog to "stand-out".

Based on the Post-Audy cali, are the settings ok to prevent "audio-hole"?
Audy LFC was set to OFF by default. Should I change this to ON?

Offline iMak

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Optimizing your speakers - taming the crossover and phase
« Reply #12 on: November 14, 2017, 17:49 »
@desray

For some reasons, the pictures in your posts are not shown, can you re upload them?

Edit:
I can see them now
« Last Edit: November 14, 2017, 18:45 by iMak »
2015 Nvidia Shield 16GB
Sony Bravia XBR-55HX929
Yamaha RX-A3050 AVR
Jamo C109, C103, C93, C10 CEN & J112 SUB (5.1.4) Speakers in Piano Black

Offline Bbos37

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Re: Optimizing your speakers - taming the crossover and phase
« Reply #13 on: February 17, 2018, 16:54 »
The frequency response of my speakers pre-Calibration:
Front L and R: 52hz-22khz
Center: 50hz-22khz
Surrounds: 52hz-22khz
Sub: 27hz-40/140hz
Klipsch DA speakers: no specs; specs only said conformed to Dolby Atmos specs

After Audy:
Fronts: 40hz
Center: 40hz
Surrounds: 40hz
Sub: 120hz
Klipsch DA: 120hz

Post-Audy, I changed to:
Fronts: 80
Center: 80
Surrounds: 80
Sub: 120
Klipsch DA: 120

I manually adjusted the sub level setting to +3db for added oomph. I may also alternate between 80z and 120hz to determine my preferred setting. Center speaker was also adjusted to +3db for my preference as I like the dialog to "stand-out".

Based on the Post-Audy cali, are the settings ok to prevent "audio-hole"?
Audy LFC was set to OFF by default. Should I change this to ON?
Leave the LFC to OFF.



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