Sub Alignment with REW's 'Alignment Tool'

This video is a quick walkthrough showing how to use the "Alignment Tool" functionality to integrate multiple subwoofers together. Most videos on this topic use the alignment tool for integrating subs with mains. However, it can also be used with just subs.

Many people do this work manually. They enter a delay for one sub into the miniDSP. Then measure. Then enter a different delay. Measure again. They repeat this process until they get a good result. The "Alignment Tool" can save a ton of time and reduce the number of sweeps you need to run to get results.

I would recommend this method of sub alignment if you have a single listening position. If you have multiple listening positions, Multi Sub Optimizer (MSO) is a better choice of tools. I have a tutorial video on that as well.

[Youthman]

One of my patrons recommended this video to other patrons during our Zoom calls tonight. Excellent job. Very easy to follow and understand.

[ripleyhrgiger]

Okay THIS video is probably the single most important one regarding REW! Delays are how you align you subs so that they work together well and holy shit I've learned that I've been going about this the wrong way.

[diamond]

I've been following Steven Smiths videos on Home Theater Gurus and happened to come across your videos. I'll now be going through all your stuff, cause this video specifically helped my wrap my head around getting everything aligned using the "Alignment Tool". Using the slider and getting a visual representation of "whats going on" made a world of difference. Thank you so much !!

[shodan]

Actually, I think that the next step before applying any EQ would be to capture an actual measurement. Would like to have seen a comparison between the predicted curve and the measured curve, but otherwise, a great and very, very helpful tutorial, thanks.

[Rayman-expertsoundpro]

Jeff, great video and explanation of how to use the alignment tool. Please keep up the great work and carry on with vidoes for next steps on EQ and alignment to mains etc. There is a lot of misinformation out there. Yours is one of the best I have seen. Well done sir!

[malsmith]

Thanks so much for this fantastic tutorial. I'm wanting to get into REW this year and I'm doing as much homework as possible but I find so many people skip steps that to them are very simple but for me as someone who's not as savvy on a computer as others can leave me sort of stranded.. Really appreciate your effort to walk us through step by step. Really looking forward to seeing your videos on how to apply EQ through mini dsp and any other info you care to share. Cheers Mark.

[HereticHulk]

This is the best video I've seen on this topic. Thank you.

[ferdinandgleinser]

Three adittional tipps here:
-You should also conciser trying negative delays. It might be that the woofer you are trying to align is already too late so you cant fix it with adding delay. You will instead need to "subtract delay" (which actually means adding delay to all the woofers from the previous measurements)
-You can klick the slider and then move it with the arrow keys on your keyboard, which makes small adjustments way more convenient.

-After aligning all woofers into one "virtual" woofer and integrating it with the mains, you should definitely check out the Group delay plot i REW to see if your subs are playing "in time" with your mains. In most cases they will be A LOT too late, even if the frequency response looks good in the crossover region.

[jimmyshoes]

Great job buddy 👍 Jeff (AKA Fattire @AVS)

I was going suggest making a video about the Alignment Tool but it seem your all over it 😀
I think this will help a ton of people out as video tutorials make the process seem so much easier. I can see myself linking this video a lot 👍

I found it strange that you didn't need any inversion for the back subs, this is the same when aligning my two sub 1 front 1 back no inversion needed and little to no delay.
I would for future videos turn off the the dark mode in REW, it comes on as default for newer versions and I find myself that it is harder to see the different sub FR's
Also I found when fine tuning the delay I click the button once that moves the delay and then use the right and left on the keyboard to visually get what I want.

Again Great Job

Jim

[davidjeanpierre]

Thanks for such an informative video! I’ve been playing around with rew the last few days and using the alignment, time and SPL features I’ve increased my output significantly across the frequency spectrum with two subs. Upon eq and uploading to my MiniDSP I have a flat response with a small -3db dip at 53hz. Keep up the good work and keep the videos coming!😁 I’m subscribing now.

[mitchjrj]

Really would have liked to see that EQ’d to a curve and flat. That is amazing response.

[Audioholics]

Nice video you did there Jeff. The only problem is you're basing the alignment of your subs on a single measurement point in the room. Multiple locations should be checked and verified. It's particularly challenging when you have multiple rows of seating and the process can be speed up using a multi-mic array. Cheers.

[duroxkilo]

nice educational video.
if one sub does improve just a fq range (like the last one did in this vid) one could use a band pass filter and increase the gain so that it covers room nulls better. if the fq is high enough one could use more than 3dB gain, depending on the listening habits.. but as the video stated, just 3dB increase requires 2X the power so proceed w/ caution. it can over-stress a sub and also, the closer a speaker and amp play to their limits the more distortion is produced, exponentially...

also, if don't have the option to add delay, both the crossover point and phase settings act as delays (technically is the other way around, delay changes phase) and one can find compromises using that.
use brown or pink noise, and use RTA to monitor live the output of the combined subs. a spectrogram works even nicer as one can see color/intensity easier...

[ggliving]

Great job! I found using arrow keys vs. mouse was easier to see small delay adjustments.

[bassdabob]

Thank you! 4 subs means 4 times the power and 4 times the cone area. 1sub 90dB will redult in 2 subs 96dB and 4 subs 102dB then. 12dB extra in a perfect world. You could have added the 4 without any delay and compare to your optimzed version to show the difference between simply 4 and 4 optimized with time alignment aswell.

[dillonmaggiano]

Great video! +10 dB is usually perceived as a doubling of loudness, which is still really impressive considering you're just time aligning the subs. It beats doubling your wattage to get a 3 db increase

[erics.]

Awesome video. Always a pleasure to see a demo of a system from someone that clearly understands it.

I haven't gotten into REW yet but I appreciate the primer even though this was a more advanced video I'm a genius so... 😉

[claytondunn]

Wow just what I have been looking for years!!!

[joemarz]

Amazing video explained plainly and clearly. Thank you

[LazayLada]

You are an angel from heaven!!! Such a time saver