End Fire Subs
Experiences,  Live System Measurements

End Fire vs Stacked Subs!

End Fire Subs : It is very rare that we get a venue that allows us to opt for an End Fire Subwoofer configuration!

However, for this particular gig the moment I reached the venue and I saw the amount of depth and space available, End Fire was now definitely an option.

The width of the audience sitting area, the width of the stage, the amount of space and depth available for the PA, had me inclined towards going for either the End Fire Array or the Stacked Subs.

All those of you, who have read my previous posts or follow me on Social media would know that ‘Subs in a Line’ is my favourite configuration. However, the drop in coverage at the end of its width is something I dont like much. Obviously there’s no doubt it has great coverage across its width, but the drop at the sides is really disappointing(unless you have subs laid across the entire width of the venue).

Another common apparent worry that most of us have with trying out different configurations, is are we loosing on SPL? Are we wasting a Sub?And questions of that sort.

So, I decided to compare both the configurations.

End fire vs Stacked Subs!
End fire vs Stacked Subs!

The End Fire Array :

End Fire Subs

In an End Fire Array, the purpose is to be able to physically reproduce the wavelength by means of the length of the End Fire Array, by separating the subs by a distance. While at the same time, we have to see to it that they all come in time, which we achieve by means of delaying all the front subs to the A Sub(t=0 Sub).

Here are the individual traces of all 4 subs :

  • Sub A : Green Coloured.
  • Sub B : Blue Coloured.
  • Sub C : Dark Green Colour.
  • Sub D : Maroon Coloured.

In the next Image, I hv put all the sub traces in the same window for an easy comparison, so we can observe their phase traces.

All the 4 subs, without any delay.

The next trace is with All Subs on but without any delay. And this will be our starting point.

End Fire Array with all subs on and without any delay.

Now to get this physical array to work as a single End Fire unit, we need to make them all come in time, which we will achieve by matching their phase traces. To attain this goal I had delay at my disposal.

After I matched their phase trace using delay and then when I unmuted all subs, this is the result.

Bluish Trace : End Fire without delay.
Greenish Trace : End fire with delay.

You can clearly observe the difference between how the array behaved with no delay and now after adding proper delay timings. That is our End Fire Array.

The upside of having an End Fire Array is that we get a good amount of cancellation at the back and thus making the stage very quiet! (I forgot to take a trace of what was happening at the back, so next time will definitely add that).

Stacked Subwoofers :

There’s not much to explain about the Stacked Subs. It is as simple as just stacking them up together.

Subwoofer Stack.

Here’s a comparison of the traces of End Fire vs Stacked Subs.

End Fire vs Stacked Subs
End Fire vs Stacked Subs.

What I found is that at the front both of them are similar in terms of coverage and response, except that the stacked subs gave 2db more compared to the End Fire.

However, at the back its as good as in the front, so the stage has a huge amount of low end! And that is the downside of Stacked Subs.

End Fire Subs
End Fire vs Stacked Subs showing -2dB offset of the Stacked Subs.

That’s all about this!

To summarize, while comapring the End Fire Array with the Stacked Subs, we are trading off 2dB for a quiter stage. I would personally anyday choose a quiter stage in that deal. And so I went ahead with the End Fire Array for this particular event.

Hope this was a good read! Feel free to comment, discuss, share your experience with End Fire and if you have any advice, please do let me know.

Thank you All. 
And a Big Thanks to J Live Sound - Ahmedabad, Malvik Bhavsar,
Jitu Gehlot and the entire J Live Team for everything!
Regards,
Dr. Rajesh Khade

3 Comments

  • Bodo Felusch

    Hello Rajesh,

    thank you for sharing your work experience!

    I am missing informations about the tuning frequency, from the pics it looks like something between 1m-1,2m and should therfore be something between 70Hz-90Hz. For my taste it is a bit high because you have constructive summation one octave below. …if your goal is cancelation behind the setup.

    Also I am missing the mic positions for the meassurement and I think here is a missmatch for comparison!
    I think the +2dB for the stacked version is not enough, I guess you have about 3m difference in meassure mic position for it. …depends on were you placed the first, 3m is if you start at 1m 🙂 …hard brainfuck with a endfired setup I made a calculator and couldn ´t sleep for 2 weeks, haha.

    For my experience (calcutation and meassurement for approval) it should be +5,5dB for the stacked version in a comparable situation or better sayed equal distance mic positions!

    PN: the meassurements/comparison of unalligned endfired subs is useless because of randomized phase differences …move the mic = random values.

    Regards from cologne
    Bodo

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