Is this a valid way to time align Sub and monitors?

[bbizzle]

Hey all!

I'm trying my best to find a simple way to time/phase align my sub and monitors. I'm using a MiniDSP nanodigi to induce latency to line up the waveforms of a single tone that both my monitors and sub share. I figure that the most important region to get aligned would be near the crossover (80 hz in my case).

So, I've generated a short 80Hz pulse and recorded the response through just my monitors (genelec 8030c) and with a umik-1. Then I play the tone and record the output with just the sub.

But the issue is that there seems to be a "warm up" period with my monitors so I don't know what "peak" to align to. My subwoofer doesn't have this warmup period issue (the first oscillation is the largest). The other issue is that the amount of delay needed to align the sub to my monitors is dependent on the frequency of the test tone. I figure phase doesn't really matter much outside of the crossover region so I'm hoping this won't be an issue.

Is this approach just fundamentally flawed? Would aligning to an IR be a better route? Thoughts?

Thanks in advance!

 

[Keith_W]

What software are you using?

I think the issue is that you don't seem to have a timing reference. With REW, you could use it to generate a timing reference. Then you simply align both to the timing reference.

With Acourate, you generate the timing reference manually by delaying the tweeter by a known number of samples. You then look for the sub peak and align it with the tweeters.

 

[ppataki]

Hey all!

I'm trying my best to find a simple way to time/phase align my sub and monitors. I'm using a MiniDSP nanodigi to induce latency to line up the waveforms of a single tone that both my monitors and sub share. I figure that the most important region to get aligned would be near the crossover (80 hz in my case).

So, I've generated a short 80Hz pulse and recorded the response through just my monitors (genelec 8030c) and with a umik-1. Then I play the tone and record the output with just the sub.

But the issue is that there seems to be a "warm up" period with my monitors so I don't know what "peak" to align to. My subwoofer doesn't have this warmup period issue (the first oscillation is the largest). The other issue is that the amount of delay needed to align the sub to my monitors is dependent on the frequency of the test tone. I figure phase doesn't really matter much outside of the crossover region so I'm hoping this won't be an issue.

Is this approach just fundamentally flawed? Would aligning to an IR be a better route? Thoughts?

Thanks in advance!

This might help:

Manually time-aligning subwoofer(s) to mains - how to

This topic was opened several times on the forum but each time it got complicated and IMHO failed to produce simple how-to procedure to do this. So, prerequisite for this procedure is that you have a device capable of adjusting mains delay and applying high pass filtering to to them in addition...

www.audiosciencereview.com

 

[ernestcarl]

Hey all!

I'm trying my best to find a simple way to time/phase align my sub and monitors. I'm using a MiniDSP nanodigi to induce latency to line up the waveforms of a single tone that both my monitors and sub share. I figure that the most important region to get aligned would be near the crossover (80 hz in my case).

So, I've generated a short 80Hz pulse and recorded the response through just my monitors (genelec 8030c) and with a umik-1. Then I play the tone and record the output with just the sub.

But the issue is that there seems to be a "warm up" period with my monitors so I don't know what "peak" to align to. My subwoofer doesn't have this warmup period issue (the first oscillation is the largest). The other issue is that the amount of delay needed to align the sub to my monitors is dependent on the frequency of the test tone. I figure phase doesn't really matter much outside of the crossover region so I'm hoping this won't be an issue.

Is this approach just fundamentally flawed? Would aligning to an IR be a better route? Thoughts?

Thanks in advance!

Might be easier to use REW's 'alignment tool' and/or overlays window to compare the phase and magnitude slopes.

 

[Sancus]

Measuring time delay for home theater with the UMIK-1 and REW

miniDSP is a leading manufacturer of Digital Audio Signal Processors for the HomeTheater, Hifi, headphone and Automotive market. Join our large community of Audiophiles, Engineers and DIYers using our innovative products.

www.minidsp.com

 

[bbizzle]

Thanks for all the input so far! I was hoping that the method I came up with would work so that people that are more comfortable working in a digital audio workstation (home studio musicians) could use this approach instead of trying to learn another piece of complicated software like REW.

Is this concept of playing a short test tone at the crossover frequency of my monitors and sub and then recording it being played back with just the monitors and then with just the sub a valid one? Or is using REW just a better approach overall?

 

[Ellebob]

You can use a test tone (sine wave) at the crossover frequency and adjust the phase of the subwoofer until the test tone is the loudest. You can use an SPL meter or SPL app on a phone since it is a relative measurement.

 

[ernestcarl]

Since you have a UMIK-1, whatever method you choose, verify by measuring the individual speaker(s) and sub — along with its sum (sub + 8030c).

 

[DavidMcRoy]

I use the simple "manual" null test as detailed on page 19 of this Neumann user guide: https://www.canford.co.uk/ProductResources/resources/N/Neumann/Neumann KH810 Manual.pdl

This is a quick synopsis, corrections or clarifications from other ASR members welcome:

1. Adjust the frequency response and level of your subwoofer relative to the other speakers in your system
2. Feed an 80Hz (or whatever your crossover frequency is) tone to the sub and, say, the front left speaker
3. Using an SPL meter, fine-tune the levels of the sub and the FL speaker so that their output is exactly equal at the crossover frequency
4. Reverse phase on the subwoofer
5. Using the SPL meter, adjust the delay of the sub for the lowest null reading at 80Hz
6. Return the subwoofer phase switch back to the opposite position
7. Reassess frequency response

Now I have a question for those who are more knowledgeable than I: Is there anything about this procedure that's audibly inferior to any other method? Is there anything potentially important that this method fails to address?

 

[Ellebob]

Neumann's method is basically the same as what I described above except they are finding the lowest spot then changing phase 180 degrees. Either should work and using both would be a verification.

 

[DavidMcRoy]

Neumann's method is basically the same as what I described above except they are finding the lowest spot then changing phase 180 degrees. Either should work and using both would be a verification.

Yes. I’m wondering whether there may be anything to gain by using the more elaborate methods posted elsewhere in this thread.

 

[ernestcarl]

I use the simple "manual" null test as detailed on page 19 of this Neumann user guide: https://www.canford.co.uk/ProductResources/resources/N/Neumann/Neumann KH810 Manual.pdl

This is a quick synopsis, corrections or clarifications from other ASR members welcome:

1. Adjust the frequency response and level of your subwoofer relative to the other speakers in your system
2. Feed an 80Hz (or whatever your crossover frequency is) tone to the sub and, say, the front left speaker
3. Using an SPL meter, fine-tune the levels of the sub and the FL speaker so that their output is exactly equal at the crossover frequency
4. Reverse phase on the subwoofer
5. Using the SPL meter, adjust the delay of the sub for the lowest null reading at 80Hz
6. Return the subwoofer phase switch back to the opposite position
7. Reassess frequency response

Now I have a question for those who are more knowledgeable than I: Is there anything about this procedure that's audibly inferior to any other method? Is there anything potentially important that this method fails to address?

Analysis of frequency response measurements would tell you if some things might be less than ideal. For example, see what Genelec does on their Grade report.

 

[TurtlePaul]

I would think that you could run an impulse response with both connected and measure the time delay between the two peaks.