# Placement for true stereo L&R subwoofers



## Phillips (Aug 12, 2011)

Hi

Can someone please advise on placement for left and right subwoofers?

I have them currently inside each main speaker.

Thanks in advance


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## AudiocRaver (Jun 6, 2012)

Sounds like a good starting place. I like the symmetry. Just curious, what is the crossover point? From your description it sounds like your main speakers are floor-standing towers, probably full range with good bass capability, so the sub crossover point would be fairly low, correct? Not a big deal, just wondering.

The symmetrical arrangement relative to the stereo field is actually of little to no importance as long as the crossover point remains low. With a 60 Hz sub crossover frequency, wavelengths being driven by the subs are mostly 5 m and longer, long enough that they will not contribute any audible directionality. That gives you some flexibility if there is a reason to arrange them elsewhere.

Any other significant factors you can share? How close to the wall? How close to corners of the room? Factors which affect how the subs couple with the room, affecting their frequency response somewhat. Have you been able to measure the frequency response of each tower/sub combo, and are you happy with it? Absent any reasons driving you to move them, I would probably leave them right where they are. That's my two cents worth.

Best of luck!


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## Phillips (Aug 12, 2011)

AudiocRaver said:


> Sounds like a good starting place. I like the symmetry. Just curious, what is the crossover point? From your description it sounds like your main speakers are floor-standing towers, probably full range with good bass capability, so the sub crossover point would be fairly low, correct? Not a big deal, just wondering.
> 
> The symmetrical arrangement relative to the stereo field is actually of little to no importance as long as the crossover point remains low. With a 60 Hz sub crossover frequency, wavelengths being driven by the subs are mostly 5 m and longer, long enough that they will not contribute any audible directionality. That gives you some flexibility if there is a reason to arrange them elsewhere.
> 
> ...



Thank you

The crossover is 80hz, have played around with 60hz. There is a room mode at 37hz. Have tried 40hz as well but the room mode still remains, not as strong though.

Yes the speakers are Energy Veritas 2.3i floorstanders with dual Velodyne DD subs.

The room is 6 meters (L) 3.8 (W) 2.8 (H).

The speakers are approx 3 feet from the side walls and also 3 feet from the front wall, these were both taken from the front middle of the drivers. The subs sit inside each speaker.

Yes i have taken measurements and not too bad, need EQ for the bass. The Velodynes coupled with REW make the subs easier. The is a null @ 80hz on the left channel for both main and sub.

The receiver is a Yamaha Z9.

Thanks again


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## primetimeguy (Jun 3, 2006)

Just to be clear, you are running a different signal (left vs right) to each sub rather than splitting the sub out connection on your receiver/amp?


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## Phillips (Aug 12, 2011)

primetimeguy said:


> Just to be clear, you are running a different signal (left vs right) to each sub rather than splitting the sub out connection on your receiver/amp?


Yes i am running a different signal L & R to each sub


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## sdurani (Oct 28, 2010)

Stereo bass isn't about directionality (since we can't localize low frequencies) but more about externalization (rather than the in-your-head effect you sometimes get from mono bass). There are a couple of papers on the topic worth reading: 

http://www.davidgriesinger.com/asa05.pdf

http://www.filmaker.com/papers/VDT23Leipz-2SW.pdf

First read the conclusion of each paper, then go back and read the details. Will help prevent MEGO. 

The upshot is that low frequency spaciousness can be detectable, but requires a couple of things: truly decorrelated (out of phase) low frequency content in recordings and a pair of subwoofers placed as far away from the listener's centre line as possible (the lower the frequency, the more the speakers have to be spread apart to hear spaciousness). 

The latter is easy, since placing the subs directly to your sides puts them at the maximum angle away from the centre line. The former is rare, since most recordings have mono bass, for compatibility with things like AM radio. 

John Eargle, for example, didn't used to sum bass to mono when making classical music recordings for the Delos International label. I doubt other music labels maintained decorrelated low frequencies as consistently in their recordings, opting instead to sum any recorded stereo bass to mono.


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## bambino (Feb 21, 2010)

If you like how they sound where they are then keep them there. Either inside of the mains or outside but closer you get to the corners of the room the boom or gain you will get.


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## Phillips (Aug 12, 2011)

sdurani said:


> Stereo bass isn't about directionality (since we can't localize low frequencies) but more about externalization (rather than the in-your-head effect you sometimes get from mono bass). There are a couple of papers on the topic worth reading:
> 
> http://www.davidgriesinger.com/asa05.pdf
> 
> ...



Thanks Sanjay i will read the papers

Correct me if have done the setup incorrect for stereo

1. Crossover 80hz Z9
2. Disabled subs crossovers
3. Eq each sub seperately
4. Checked phase

All the setup was done for each L&R channel seperately

Then i measured both L&R combined, but ended up changing the left channel sub phase, this doesn't make sense, seperately the left channel was ok, but when combined the phase required reversing.


With the same setup sub positions to setup mono subs 

Do the same as stereo but measure the subs and mains as one, levels, etc?

Thanks in advance


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## Phillips (Aug 12, 2011)

bambino said:


> If you like how they sound where they are then keep them there. Either inside of the mains or outside but closer you get to the corners of the room the boom or gain you will get.



Thank you

I can't put them on the outside cause they would be close to the corners.


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## jtalden (Mar 12, 2009)

Phillips said:


> Thanks Sanjay i will read the papers
> 
> Correct me if have done the setup incorrect for stereo
> 
> ...


Per "Subs Velodynes.zip" in Post 9 and "Subs.Zip" in Post 20 of your previous thread, "Need help with Graphs", I had noticed that your 2 subs are connected with reverse polarity. 

This can be seen in the Impulse Responses of the 2 subs:









The IR initial reaction is in opposite directions as show above. It also showed up in the SPL output when the subs were measured together. 

This is the reason that there is better combined response when one of subs set for reverse polarity. There is no need to be concerned with that setting; it is the right thing to do. REW provided you the tool to identify the problem and correct it. :sn:


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## tpcurrie (Nov 27, 2012)

Have you tried the completely unsophisticated but slightly obvious method? Place one sub at the listening location, play test tone, comb the room for the loudest response using your sound meter.... wherever the 1 or 2 loudest responses are, that is your starting point. Adjust from there to taste.

Since, as others have said, lower bass is not directional, your subs do not have to be next to your speakers, you really just want to place them where they sound best, IMO


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## Phillips (Aug 12, 2011)

jtalden said:


> Per "Subs Velodynes.zip" in Post 9 and "Subs.Zip" in Post 20 of your previous thread, "Need help with Graphs", I had noticed that your 2 subs are connected with reverse polarity.
> 
> This can be seen in the Impulse Responses of the 2 subs:
> 
> ...


Thank you

Matter of interest can this way (IR graph) help in the distance setting in the Z9?

Thanks again


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## jtalden (Mar 12, 2009)

Your subs are equal distance from the LP so they don't need a delay adjustment between them. Even if they were different by 0.5 m or so that would not have a significant impact their combined response (using a 80 Hz XO freq).

Regarding the relative distance between the main speaker setting and the subs:
- Setting the distances by measurement is fine. There may be small delay in subs that underestimate the ideal distance setting, but that is usually also within the 0.5 m or so that is not significant to SPL response. 

- The other issue is to check which SW polarity provide the most output in the XO range. You have already done that in the other thread.

- After that if you want to fine tune the SW distance prior to any EQ settings you can use the REW RTA feature using Pink PN noise and fine tune the SW distance adjustment to get the maximum SPL in the XO range.

The fine tuning is not really needed for good results however.

If you are manually setting EQ that is done after these basic distance setup steps.

Yes, there are other ways to measure and set the distances, but they are more complicated and the final results are not likely to be significantly different.


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## sdurani (Oct 28, 2010)

Phillips said:


> Thanks Sanjay i will read the papers


For the moment, just read the conclusions.


Phillips said:


> Correct me if have done the setup incorrect for stereo
> 
> 1. Crossover 80hz Z9
> 2. Disabled subs crossovers
> ...


Looks fine, except I would set phase of each sub to match the speakers on each side rather than matching the other sub. If you left sub is getting content below 80Hz from the left channels (front, side, rear), then it should be in phase with those speakers at the crossover point. After all, that sub is acting as the bottom end of those three speakers.


Phillips said:


> Then i measured both L&R combined, but ended up changing the left channel sub phase, this doesn't make sense, seperately the left channel was ok, but when combined the phase required reversing.


When I used to run stereo subs, I wasn't concerned with the phase of the subs being aligned, since they would be receiving different and/or decorrelated signals. The Greisinger paper I linked to explains why not having the two subs phase aligned actually helps the stereo bass effect (IF that's what you're trying to accomplish).


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## Phillips (Aug 12, 2011)

tpcurrie said:


> Have you tried the completely unsophisticated but slightly obvious method? Place one sub at the listening location, play test tone, comb the room for the loudest response using your sound meter.... wherever the 1 or 2 loudest responses are, that is your starting point. Adjust from there to taste.
> 
> Since, as others have said, lower bass is not directional, your subs do not have to be next to your speakers, you really just want to place them where they sound best, IMO


Thanks for your reply

Yes i have considered that and tried to a very little extent but not many places i can place them, tried the other side of the spealers but ended up with more nulls.


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## Phillips (Aug 12, 2011)

jtalden said:


> Your subs are equal distance from the LP so they don't need a delay adjustment between them. Even if they were different by 0.5 m or so that would not have a significant impact their combined response (using a 80 Hz XO freq).



Thank you
So change the setting to 0 meters (previously 7.25 meters by the Z9) in the receiver?
If its stereo subs (each sub looks after each speaker independently) why are we looking at combined response?




jtalden said:


> Regarding the relative distance between the main speaker setting and the subs:
> - Setting the distances by measurement is fine. There may be small delay in subs that underestimate the ideal distance setting, but that is usually also within the 0.5 m or so that is not significant to SPL response.


I thought the DDs produced a delay?



jtalden said:


> - The other issue is to check which SW polarity provide the most output in the XO range. You have already done that in the other thread.



Something i don't understand (same as above) with the combined response the polarity needs reversing in the left sub, but when measureed seperately the left sub shows a null at the crossover?



Thank you


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## Phillips (Aug 12, 2011)

sdurani said:


> For the moment, just read the conclusions. Looks fine, except I would set phase of each sub to match the speakers on each side rather than matching the other sub. If you left sub is getting content below 80Hz from the left channels (front, side, rear), then it should be in phase with those speakers at the crossover point. After all, that sub is acting as the bottom end of those three speakers. When I used to run stereo subs, I wasn't concerned with the phase of the subs being aligned, since they would be receiving different and/or decorrelated signals. The Greisinger paper I linked to explains why not having the two subs phase aligned actually helps the stereo bass effect (IF that's what you're trying to accomplish).



Thank you
Absolutely that what i am trying to accomplish.
I have wondered that why if each sub is supporting its own channel (talking 2 channel muisc 95% of the time) why i am measuring combined responses?

I will get onto those papers


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## jtalden (Mar 12, 2009)

Phillips said:


> Thank you
> So change the setting to 0 meters (previously 7.25 meters by the Z9) in the receiver?
> If its stereo subs (each sub looks after each speaker independently) why are we looking at combined response?
> 
> ...


No, you missed the intent of each of the points I listed. I suggest much more reading on your part to become more familiar with the concepts.


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## sdurani (Oct 28, 2010)

Phillips said:


> Absolutely that what i am trying to accomplish.
> I have wondered that why if each sub is supporting its own channel (talking 2 channel muisc 95% of the time) why i am measuring combined responses?


Exactly. As with your subs, measuring the combined response of your main L/R speakers will also likely show a cancellation notch that you would not see when measuring each speaker individually. However, your human hearing won't notice the notch, even when you can clearly measure it (otherwise "stereo" would never have worked). 

IF 95% of the time you're listening to a 2-speaker + 2-subwoofer configuration, then it makes things easier. I would still move the subs directly to my sides, to maximize the stereo bass effect, but I would make sure that each sub is level & phase matched to its respective main speaker at the crossover point. Keep in mind that we can't hear directionality in the low frequencies, so moving the subs away from your main L/R speakers won't be a problem (otherwise sub-sat systems would never have worked).


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## primetimeguy (Jun 3, 2006)

sdurani said:


> However, your human hearing won't notice the notch, even when you can clearly measure it (otherwise "stereo" would never have worked).


I don't want to hijack the thread, but can you expand on this more? Is this assumption it is a very narrow notch or why wouldn't we hear it?


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## sdurani (Oct 28, 2010)

primetimeguy said:


> I don't want to hijack the thread, but can you expand on this more? Is this assumption it is a very narrow notch or why wouldn't we hear it?


I should have said notches (plural), as in comb filtering. There are explanations from various sources (Toole, Blauert, etc), describing differences between what a microphone picks up vs how we humans hear. One of the better ones can be found at the Axiom Audio website: 

http://www.axiomaudio.com/blog/comb-filtering-–-popular-misconceptions/ 

It's one of the reasons why room correction systems typically measure and EQ each speaker independently, rather than a combination of speakers, even though we listen to the latter.


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## primetimeguy (Jun 3, 2006)

Thanks, I I thought it was in reference to the bass frequencies.. My bad.


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## Phillips (Aug 12, 2011)

Basically the way i am treating setup is like the sub was built into the speaker (like some speaker designs e.g. Definitive etc). 

In theory there woofers (subs) would be in phase in their individual speaker?


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## Phillips (Aug 12, 2011)

jtalden said:


> Per "Subs Velodynes.zip" in Post 9 and "Subs.Zip" in Post 20 of your previous thread, "Need help with Graphs", I had noticed that your 2 subs are connected with reverse polarity.
> 
> This can be seen in the Impulse Responses of the 2 subs:
> 
> ...



I tried to show the IR reponse like above with my graphs but is not showing.

Please can you describe how you got this?


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## jtalden (Mar 12, 2009)

Phillips said:


> I tried to show the IR reponse like above with my graphs but is not showing.
> 
> Please can you describe how you got this?


Open the "controls" panel in the "Impulse" Tab and use the "T=0 offset" on each of the two IR measurements as needed to align them to 0 ms.

You can then open the "overlays" window and "Impulse" tab to view them overlaid. 

The REW "Help" information is very well organized and well written for these basics.


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## Phillips (Aug 12, 2011)

jtalden said:


> Per "Subs Velodynes.zip" in Post 9 and "Subs.Zip" in Post 20 of your previous thread, "Need help with Graphs", I had noticed that your 2 subs are connected with reverse polarity.
> 
> This can be seen in the Impulse Responses of the 2 subs:
> 
> ...



By looking at these can i find the best distance setting with work/time?

Thank you


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## AudiocRaver (Jun 6, 2012)

This thread is a little cold, but it left off with a question. Did it get answered for you somehow? Anything more we can do to help?


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## Phillips (Aug 12, 2011)

AudiocRaver said:


> This thread is a little cold, but it left off with a question. Did it get answered for you somehow? Anything more we can do to help?


Thank you for replying.

Currently i am using Mono subs, which to be honest i still prefer the sound of stereo, seems to have more air/openness around the sound

Presently i am trying to setup the calibrated EMM-6 with the Steinberg CI-1 sound card pre with the ASIO drivers. 
Appears John is going to try some coding to make the Steinberg/Yamaha ASIO driver work, currently i have gone cold on measuring until this has been resolved, hoping Johns thoughts will do so.

I am currently using the Omnimic V2 and the laptops sound card.

One thing is with the phase. 
When i set the phase to 0 for both subs individually and measure individually this seems to give the best response, but when i measure all running (both mains and subs together) the response isn't as good, yet i reverse the the left and this improves the response for combined only, hope this makes sense?

The way i think is that i am trying to setup each sub with each main (stereo), so combined doesn't matter?


Thanks again, would be great to get this under way again.


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## AudiocRaver (Jun 6, 2012)

Phillips said:


> Currently i am using Mono subs, which to be honest i still prefer the sound of stereo, seems to have more air/openness around the sound


Stereo subs is the way I would try to go, too.



> ...currently i have gone cold on measuring until this has been resolved...


Not being able to measure will definitely slow you down.



> One thing is with the phase. When i set the phase to 0 for both subs individually and measure individually this seems to give the best response, but when i measure all running (both mains and subs together) the response isn't as good, yet i reverse the the left and this improves the response for combined only, hope this makes sense?
> 
> The way i think is that i am trying to setup each sub with each main (stereo), so combined doesn't matter?


With your stereo mains, if you run the same measurement signal through left and right speakers at the same time, you will get phase reinforcements and cancellations at different frequencies, and the resulting curve will look totally crazy. Move the measurement microphone a few inches and you will get a completely different crazy curve. This kind of measurement tells you nothing meaningful.

You want to get a good response curve with left sub and left main working together, and then get a good response curve with right sub and right main working together. That is the main goal you are working toward.

Some might argue with me on this next part, but here goes anyway. Running stereo subs, since most music is mixed with most or all the low frequencies to center, it turns out that your two subs will be running close to the same signal most of the time, even set up for true stereo (the main argument for mono subs in the first place). So I would want to see a response curve with just the subs, no mains, same signal to both subs, to see that the response with them working together is at least fairly good, too. (This might be what you are suggesting, apologies if I am covering ground you are already familiar with.) If it is not, then you have to decide if you're going to (1) come up with a compromise between sub+main fidelity and sub+sub fidelity that gives you good true stereo performance AND has your subs behaving nicely together - depending on factors, this might be easy or it might be impossible; OR (2) take the easier route of mono subs, put them close together so they play nice and call it good, equalizing the way you normally would with a single sub.

If it sounds like stereo subs are not worth the trouble, you might be right. The benefits of stereo subs over mono are not huge, and it might be a lot more work than setting up mono subs. That said, the perfectionist in me still says to at least give the true stereo set up a try, and see if you can get satisfactory results fairly easily, if not then back off to mono subs. A little bit of repositioning of the subs might help, but playing with sub phase will probably mess up the sub-to-main phase relationship, which would be bad (this might be what you meant in your comments, apologies again if I am covering old ground).

Someone is bound to say that the whole exercise of trying to get stereo subs working well together is silly, you have the same issues with any stereo full range speakers, and they would be right. Only with separate subs, you have some flexibility to try to do something about it, whereas with full-range mains, you do not. For that matter, you could argue that mains placement could be adjusted for optimal combined low-frequency performance, but that would surely conflict with placement for best imaging and sound stage, which are FAR more important.

Enough rambling. That is my take. Good luck, keep us posted.


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## jtalden (Mar 12, 2009)

Phillips said:


> ....
> One thing is with the phase.
> When i set the phase to 0 for both subs individually and measure individually this seems to give the best response, but when i measure all running (both mains and subs together) the response isn't as good, yet i reverse the the left and this improves the response for combined only, hope this makes sense?


Per Post 10 above:
The measurements you initially posted indicated the 2 SWs were setup with opposite polarity when you indicated they were the same polarity in your descriptions of the settings.

Polarity is different from the phase adjustment on the sub. It sounds like you have both have both polarity and phase controls on your subs. The phase can just be left a 0 degs for now as the polarity is a major issue that needs to reconfirmed first.

Regardless of the SW switch setting indication/position it is important to insure that the polarity of both subs are set the same as indicated by measurements, otherwise the SWs are working against each other. 

An IR chart as in post 10 is the best indicator of when they are set correctly:
The initial rise of the impulse needs to be in the same direction.  That is they must both be going up (SW cones both moving out first) or both going down (SW cones both moving in first). Post 10 shows that they are reversed - working against each other.

The combined SPL is another indicator: 
When both SW polarities measure the same, the combined SW SPL response will be higher than either of the individual SW SPL measurements over most of the SW range. The combined SW SPL in your previous measurements indicate the same thing that the IR measurement indicates i.e., one of the SWs needs to have the polarity reversed in order that they are actually same.

This is why you found better SPL results when one of the SW is set to "reverse" polarity. It is actually setting them to the same polarity.

Possibly you had previously understood and corrected this, but your comment above left me wondering.


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## Phillips (Aug 12, 2011)

Thank you, hopefully John can get the ASIO for the Steinberg/Yamaha working.

Just to confirm when setting up dual stereo subs, only thing that matters is each sub is set up with each main e.g. left main with left sub, not combined all mains and subs playing, this would be mono anyway?

I have attached some old .mdat measurements that i found.

All of these are not EQed with both subs polarity set to plus, not that probaly makes a difference with these measurements trying to set the phase

I still can't find how to set the "Impulse" to site the phase, i get two different shaped IR. I need to use "Step" to adjust to be the same as the other measurement. Help with this would be appreciated, obvoiusly missing something? 

Thanks again

View attachment Left Right Subs.zip


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## JohnM (Apr 11, 2006)

Phillips said:


> Thank you, hopefully John can get the ASIO for the Steinberg/Yamaha working.


You reported previously that the card worked fine with the Java drivers, why don't you use those to measure?


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## jtalden (Mar 12, 2009)

Phillips said:


> …
> 
> Just to confirm when setting up dual stereo subs, only thing that matters is each sub is set up with each main e.g. left main with left sub, not combined all mains and subs playing, this would be mono anyway?


Yes.
[It is normally recommended that multiple subs be set up as mono. This way a bass signal from any individual channel will have the benefit of a smoother SPL as both SWs will be operating and it is easier to achieve a smooth response with EQ when 2 or more SWs are running together. That said; some still prefer to use stereo subs and EQ them separately as you intend to do.] 



> I have attached some old .mdat measurements that i found.
> 
> All of these are not EQed with both subs polarity set to plus, not that probaly makes a difference with these measurements trying to set the phase.


In these measurements the 2 SWs are the same polarity so all is well. Possibly the earlier measurements were mislabeled or I just misread them.



> I still can't find how to set the "Impulse" to site the phase, i get two different shaped IR. I need to use "Step" to adjust to be the same as the other measurement. Help with this would be appreciated, obvoiusly missing something?


The Step Response will also show if the there is a polarity problem so that was a good workaround solution.
I do not know why you can’t see the IR. A picture of what you see would help. Is the check box at the bottom of the chart by the measurement selected? Is your scale set to show the area around 0 ms? Is the "Normalize" box checked? Below is what it looks like on my machine after I offset both SW IRs to align them nearer to 0 ms. SWR needed -37.6 ms and SWL needed -19.6 ms as shown. REW automatically offsets them to place the largest peak at 0 ms and with these two IR responses that resulted in different positions making them harder to read. My repositioning was just for clarity.


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## Phillips (Aug 12, 2011)

JohnM said:


> You reported previously that the card worked fine with the Java drivers, why don't you use those to measure?



Sorry John I thought that you were going to try possible codes because of 3rd party for the next version update which i see it has been released?

I thought ASIO would be better.


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## Phillips (Aug 12, 2011)

jtalden said:


> Yes.
> [It is normally recommended that multiple subs be set up as mono. This way a bass signal from any individual channel will have the benefit of a smoother SPL as both SWs will be operating and it is easier to achieve a smooth response with EQ when 2 or more SWs are running together. That said; some still prefer to use stereo subs and EQ them separately as you intend to do.]
> 
> 
> ...



Thanks for that.

I tried that on the mains but doesn't look the same,is there some other adjustment?

When i do the step with the right main and right sub it appears they are out of phase?

Sorry i thought that minus polarity is the same as 180 phase?

Thanks again


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## JohnM (Apr 11, 2006)

ASIO vs Java shouldn't make any difference to data quality, it is just a different software interface to the same soundcard. I included updated ASIO dlls in the V5.01 beta 12 version (latest versions from the 3rd party provider of the ASIO interface code).


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## Phillips (Aug 12, 2011)

JohnM said:


> ASIO vs Java shouldn't make any difference to data quality, it is just a different software interface to the same soundcard. I included updated ASIO dlls in the V5.01 beta 12 version (latest versions from the 3rd party provider of the ASIO interface code).


Thanks John i tried beta 12 but didn't work either.


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## jtalden (Mar 12, 2009)

Phillips said:


> ...
> I tried that on the mains but doesn't look the same,is there some other adjustment?


The FL and FR mains IR’s look normal as shown below. Have you selected the “%FS” mode? If that is not it, then I need to see the settings and screen you are seeing. I am out of guesses without more help from you.












> When i do the step with the right main and right sub it appears they are out of phase?


Possibly you are seeing a room mode impacting the FR+SW? A large null in the XO frequency range is not unusual, particularly with only one SW operating.

The Step response is not a substitute for a Phase response. It is impossible to look at a step response and comment accurately on the Phase response. To accurately get the phase response is a little more complicated so it is not easy to simply explain. There are some other threads that touch on Phase in detail. For good results it is adequate to focus on achieving a smooth SPL response. SPL is the most important parameter for good sound quality.

Just set the distances using a tape measure and then adjust the SW distance as needed to get the greatest SPL response through the XO range. This can be done using the REW RTA function. Then adjust the EQ settings as needed. Do this for each main and SW and pick a good compromise setting for the SW distance.

[If you are going to use an automated setup system like Audyssey that sets distances and EQ automatically then this manual work is for naught. Sorry it’s late and I have lost track of your overall system and objectives. I hope I am not just causing more confusion than help.] 



> Sorry i thought that minus polarity is the same as 180 phase?


Well it is if we are thinking of a polarity switch and not a phase adjustment control. The phase adjustment control normally goes from 0 to 180° in increments and only impacts the phase at the frequencies near the XO point. Polarity impacts the phase equally across all frequencies (a 180° change across all frequencies). A polarity change is simply a reversal of the positive and negative wiring of the speaker regardless of whether that is done with a switch on the SW or by reversing the wiring connections at a p-amp or preamp.


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## Phillips (Aug 12, 2011)

jtalden said:


> The FL and FR mains IR’s look normal as shown below. Have you selected the “%FS” mode? If that is not it, then I need to see the settings and screen you are seeing. I am out of guesses without more help from you.
> 
> View attachment 40148
> 
> ...



The reciever is a Yamaha Z9 and i don't like what YPAO is doing with the sound, it has manual (basic).
The speakers are Veritas 2.3i (floorstanders)
The subs are dual Velodyne Digital Drive
No you aren't causing confusion, appreciate your help.






jtalden said:


> Well it is if we are thinking of a polarity switch and not a phase adjustment control. The phase adjustment control normally goes from 0 to 180° in increments and only impacts the phase at the frequencies near the XO point. Polarity impacts the phase equally across all frequencies (a 180° change across all frequencies). A polarity change is simply a reversal of the positive and negative wiring of the speaker regardless of whether that is done with a switch on the SW or by reversing the wiring connections at a p-amp or preamp.



The Velodynes have both Polarity + and - and also Phase 0-180 with 15 increments.

I have attached my IR graph with the same adjustments.

Thanks again

IR Left main


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## jtalden (Mar 12, 2009)

That looks good. All you need to do is zoom in on the time scale to to match my chart. Mine scale was set about -0.2 to +0.7 MS in order to see the detail.


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## Phillips (Aug 12, 2011)

jtalden said:


> That looks good. All you need to do is zoom in on the time scale to to match my chart. Mine scale was set about -0.2 to +0.7 MS in order to see the detail.



Thank you

Sorry still not able to get it like yours, please can you send a example like last time.

Thanks for your time


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## jtalden (Mar 12, 2009)

Your time scale is -60 to 300 ms. Zoom in or reset the scale as suggested above. See REW help.


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